xref: /linux/lib/Kconfig.debug (revision 7fc2cd2e4b398c57c9cf961cfea05eadbf34c05c)
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.  Requires GCC 5.0+ or Clang
346	  5.0+, binutils 2.26+, and zlib.
347
348	  Users of dpkg-deb via debian/rules may find an increase in
349	  size of their debug .deb packages with this config set, due to the
350	  debug info being compressed with zlib, then the object files being
351	  recompressed with a different compression scheme. But this is still
352	  preferable to setting KDEB_COMPRESS or DPKG_DEB_COMPRESSOR_TYPE to
353	  "none" which would be even larger.
354
355config DEBUG_INFO_COMPRESSED_ZSTD
356	bool "Compress debugging information with zstd"
357	depends on $(cc-option,-gz=zstd)
358	depends on $(ld-option,--compress-debug-sections=zstd)
359	help
360	  Compress the debug information using zstd.  This may provide better
361	  compression than zlib, for about the same time costs, but requires newer
362	  toolchain support.  Requires GCC 13.0+ or Clang 16.0+, binutils 2.40+, and
363	  zstd.
364
365endchoice # "Compressed Debug information"
366
367config DEBUG_INFO_SPLIT
368	bool "Produce split debuginfo in .dwo files"
369	depends on $(cc-option,-gsplit-dwarf)
370	# RISC-V linker relaxation + -gsplit-dwarf has issues with LLVM and GCC
371	# prior to 12.x:
372	# https://github.com/llvm/llvm-project/issues/56642
373	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99090
374	depends on !RISCV || GCC_VERSION >= 120000
375	help
376	  Generate debug info into separate .dwo files. This significantly
377	  reduces the build directory size for builds with DEBUG_INFO,
378	  because it stores the information only once on disk in .dwo
379	  files instead of multiple times in object files and executables.
380	  In addition the debug information is also compressed.
381
382	  Requires recent gcc (4.7+) and recent gdb/binutils.
383	  Any tool that packages or reads debug information would need
384	  to know about the .dwo files and include them.
385	  Incompatible with older versions of ccache.
386
387config DEBUG_INFO_BTF
388	bool "Generate BTF type information"
389	depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
390	depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
391	depends on BPF_SYSCALL
392	depends on PAHOLE_VERSION >= 116
393	depends on DEBUG_INFO_DWARF4 || PAHOLE_VERSION >= 121
394	# pahole uses elfutils, which does not have support for Hexagon relocations
395	depends on !HEXAGON
396	help
397	  Generate deduplicated BTF type information from DWARF debug info.
398	  Turning this on requires pahole v1.16 or later (v1.21 or later to
399	  support DWARF 5), which will convert DWARF type info into equivalent
400	  deduplicated BTF type info.
401
402config PAHOLE_HAS_SPLIT_BTF
403	def_bool PAHOLE_VERSION >= 119
404
405config PAHOLE_HAS_BTF_TAG
406	def_bool PAHOLE_VERSION >= 123
407	depends on CC_IS_CLANG
408	help
409	  Decide whether pahole emits btf_tag attributes (btf_type_tag and
410	  btf_decl_tag) or not. Currently only clang compiler implements
411	  these attributes, so make the config depend on CC_IS_CLANG.
412
413config PAHOLE_HAS_LANG_EXCLUDE
414	def_bool PAHOLE_VERSION >= 124
415	help
416	  Support for the --lang_exclude flag which makes pahole exclude
417	  compilation units from the supplied language. Used in Kbuild to
418	  omit Rust CUs which are not supported in version 1.24 of pahole,
419	  otherwise it would emit malformed kernel and module binaries when
420	  using DEBUG_INFO_BTF_MODULES.
421
422config DEBUG_INFO_BTF_MODULES
423	bool "Generate BTF type information for kernel modules"
424	default y
425	depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
426	help
427	  Generate compact split BTF type information for kernel modules.
428
429config MODULE_ALLOW_BTF_MISMATCH
430	bool "Allow loading modules with non-matching BTF type info"
431	depends on DEBUG_INFO_BTF_MODULES
432	help
433	  For modules whose split BTF does not match vmlinux, load without
434	  BTF rather than refusing to load. The default behavior with
435	  module BTF enabled is to reject modules with such mismatches;
436	  this option will still load module BTF where possible but ignore
437	  it when a mismatch is found.
438
439config GDB_SCRIPTS
440	bool "Provide GDB scripts for kernel debugging"
441	help
442	  This creates the required links to GDB helper scripts in the
443	  build directory. If you load vmlinux into gdb, the helper
444	  scripts will be automatically imported by gdb as well, and
445	  additional functions are available to analyze a Linux kernel
446	  instance. See Documentation/process/debugging/gdb-kernel-debugging.rst
447	  for further details.
448
449endif # DEBUG_INFO
450
451config FRAME_WARN
452	int "Warn for stack frames larger than"
453	range 0 8192
454	default 0 if KMSAN
455	default 2048 if GCC_PLUGIN_LATENT_ENTROPY
456	default 2048 if PARISC
457	default 1536 if (!64BIT && XTENSA)
458	default 1280 if !64BIT
459	default 2048 if 64BIT
460	help
461	  Tell the compiler to warn at build time for stack frames larger than this.
462	  Setting this too low will cause a lot of warnings.
463	  Setting it to 0 disables the warning.
464
465config STRIP_ASM_SYMS
466	bool "Strip assembler-generated symbols during link"
467	default n
468	help
469	  Strip internal assembler-generated symbols during a link (symbols
470	  that look like '.Lxxx') so they don't pollute the output of
471	  get_wchan() and suchlike.
472
473config READABLE_ASM
474	bool "Generate readable assembler code"
475	depends on DEBUG_KERNEL
476	depends on CC_IS_GCC
477	help
478	  Disable some compiler optimizations that tend to generate human unreadable
479	  assembler output. This may make the kernel slightly slower, but it helps
480	  to keep kernel developers who have to stare a lot at assembler listings
481	  sane.
482
483config HEADERS_INSTALL
484	bool "Install uapi headers to usr/include"
485	help
486	  This option will install uapi headers (headers exported to user-space)
487	  into the usr/include directory for use during the kernel build.
488	  This is unneeded for building the kernel itself, but needed for some
489	  user-space program samples. It is also needed by some features such
490	  as uapi header sanity checks.
491
492config DEBUG_SECTION_MISMATCH
493	bool "Enable full Section mismatch analysis"
494	depends on CC_IS_GCC
495	help
496	  The section mismatch analysis checks if there are illegal
497	  references from one section to another section.
498	  During linktime or runtime, some sections are dropped;
499	  any use of code/data previously in these sections would
500	  most likely result in an oops.
501	  In the code, functions and variables are annotated with
502	  __init,, etc. (see the full list in include/linux/init.h),
503	  which results in the code/data being placed in specific sections.
504	  The section mismatch analysis is always performed after a full
505	  kernel build, and enabling this option causes the following
506	  additional step to occur:
507	  - Add the option -fno-inline-functions-called-once to gcc commands.
508	    When inlining a function annotated with __init in a non-init
509	    function, we would lose the section information and thus
510	    the analysis would not catch the illegal reference.
511	    This option tells gcc to inline less (but it does result in
512	    a larger kernel).
513
514config SECTION_MISMATCH_WARN_ONLY
515	bool "Make section mismatch errors non-fatal"
516	default y
517	help
518	  If you say N here, the build process will fail if there are any
519	  section mismatch, instead of just throwing warnings.
520
521	  If unsure, say Y.
522
523config DEBUG_FORCE_FUNCTION_ALIGN_64B
524	bool "Force all function address 64B aligned"
525	depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC || RISCV || S390)
526	select FUNCTION_ALIGNMENT_64B
527	help
528	  There are cases that a commit from one domain changes the function
529	  address alignment of other domains, and cause magic performance
530	  bump (regression or improvement). Enable this option will help to
531	  verify if the bump is caused by function alignment changes, while
532	  it will slightly increase the kernel size and affect icache usage.
533
534	  It is mainly for debug and performance tuning use.
535
536#
537# Select this config option from the architecture Kconfig, if it
538# is preferred to always offer frame pointers as a config
539# option on the architecture (regardless of KERNEL_DEBUG):
540#
541config ARCH_WANT_FRAME_POINTERS
542	bool
543
544config FRAME_POINTER
545	bool "Compile the kernel with frame pointers"
546	depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
547	default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
548	help
549	  If you say Y here the resulting kernel image will be slightly
550	  larger and slower, but it gives very useful debugging information
551	  in case of kernel bugs. (precise oopses/stacktraces/warnings)
552
553config OBJTOOL
554	bool
555
556config OBJTOOL_WERROR
557	bool "Upgrade objtool warnings to errors"
558	depends on OBJTOOL && !COMPILE_TEST
559	help
560	  Fail the build on objtool warnings.
561
562	  Objtool warnings can indicate kernel instability, including boot
563	  failures.  This option is highly recommended.
564
565	  If unsure, say Y.
566
567config STACK_VALIDATION
568	bool "Compile-time stack metadata validation"
569	depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
570	select OBJTOOL
571	default n
572	help
573	  Validate frame pointer rules at compile-time.  This helps ensure that
574	  runtime stack traces are more reliable.
575
576	  For more information, see
577	  tools/objtool/Documentation/objtool.txt.
578
579config NOINSTR_VALIDATION
580	bool
581	depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
582	select OBJTOOL
583	default y
584
585config VMLINUX_MAP
586	bool "Generate vmlinux.map file when linking"
587	depends on EXPERT
588	help
589	  Selecting this option will pass "-Map=vmlinux.map" to ld
590	  when linking vmlinux. That file can be useful for verifying
591	  and debugging magic section games, and for seeing which
592	  pieces of code get eliminated with
593	  CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
594
595config BUILTIN_MODULE_RANGES
596	bool "Generate address range information for builtin modules"
597	depends on !LTO
598	depends on VMLINUX_MAP
599	help
600	 When modules are built into the kernel, there will be no module name
601	 associated with its symbols in /proc/kallsyms.  Tracers may want to
602	 identify symbols by module name and symbol name regardless of whether
603	 the module is configured as loadable or not.
604
605	 This option generates modules.builtin.ranges in the build tree with
606	 offset ranges (per ELF section) for the module(s) they belong to.
607	 It also records an anchor symbol to determine the load address of the
608	 section.
609
610config DEBUG_FORCE_WEAK_PER_CPU
611	bool "Force weak per-cpu definitions"
612	depends on DEBUG_KERNEL
613	help
614	  s390 and alpha require percpu variables in modules to be
615	  defined weak to work around addressing range issue which
616	  puts the following two restrictions on percpu variable
617	  definitions.
618
619	  1. percpu symbols must be unique whether static or not
620	  2. percpu variables can't be defined inside a function
621
622	  To ensure that generic code follows the above rules, this
623	  option forces all percpu variables to be defined as weak.
624
625endmenu # "Compiler options"
626
627menu "Generic Kernel Debugging Instruments"
628
629config MAGIC_SYSRQ
630	bool "Magic SysRq key"
631	depends on !UML
632	help
633	  If you say Y here, you will have some control over the system even
634	  if the system crashes for example during kernel debugging (e.g., you
635	  will be able to flush the buffer cache to disk, reboot the system
636	  immediately or dump some status information). This is accomplished
637	  by pressing various keys while holding SysRq (Alt+PrintScreen). It
638	  also works on a serial console (on PC hardware at least), if you
639	  send a BREAK and then within 5 seconds a command keypress. The
640	  keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
641	  Don't say Y unless you really know what this hack does.
642
643config MAGIC_SYSRQ_DEFAULT_ENABLE
644	hex "Enable magic SysRq key functions by default"
645	depends on MAGIC_SYSRQ
646	default 0x1
647	help
648	  Specifies which SysRq key functions are enabled by default.
649	  This may be set to 1 or 0 to enable or disable them all, or
650	  to a bitmask as described in Documentation/admin-guide/sysrq.rst.
651
652config MAGIC_SYSRQ_SERIAL
653	bool "Enable magic SysRq key over serial"
654	depends on MAGIC_SYSRQ
655	default y
656	help
657	  Many embedded boards have a disconnected TTL level serial which can
658	  generate some garbage that can lead to spurious false sysrq detects.
659	  This option allows you to decide whether you want to enable the
660	  magic SysRq key.
661
662config MAGIC_SYSRQ_SERIAL_SEQUENCE
663	string "Char sequence that enables magic SysRq over serial"
664	depends on MAGIC_SYSRQ_SERIAL
665	default ""
666	help
667	  Specifies a sequence of characters that can follow BREAK to enable
668	  SysRq on a serial console.
669
670	  If unsure, leave an empty string and the option will not be enabled.
671
672config DEBUG_FS
673	bool "Debug Filesystem"
674	help
675	  debugfs is a virtual file system that kernel developers use to put
676	  debugging files into.  Enable this option to be able to read and
677	  write to these files.
678
679	  For detailed documentation on the debugfs API, see
680	  Documentation/filesystems/.
681
682	  If unsure, say N.
683
684choice
685	prompt "Debugfs default access"
686	depends on DEBUG_FS
687	default DEBUG_FS_ALLOW_ALL
688	help
689	  This selects the default access restrictions for debugfs.
690	  It can be overridden with kernel command line option
691	  debugfs=[on,no-mount,off]. The restrictions apply for API access
692	  and filesystem registration.
693
694config DEBUG_FS_ALLOW_ALL
695	bool "Access normal"
696	help
697	  No restrictions apply. Both API and filesystem registration
698	  is on. This is the normal default operation.
699
700config DEBUG_FS_DISALLOW_MOUNT
701	bool "Do not register debugfs as filesystem"
702	help
703	  The API is open but filesystem is not loaded. Clients can still do
704	  their work and read with debug tools that do not need
705	  debugfs filesystem.
706
707config DEBUG_FS_ALLOW_NONE
708	bool "No access"
709	help
710	  Access is off. Clients get -PERM when trying to create nodes in
711	  debugfs tree and debugfs is not registered as a filesystem.
712	  Client can then back-off or continue without debugfs access.
713
714endchoice
715
716source "lib/Kconfig.kgdb"
717source "lib/Kconfig.ubsan"
718source "lib/Kconfig.kcsan"
719
720endmenu
721
722menu "Networking Debugging"
723
724source "net/Kconfig.debug"
725
726endmenu # "Networking Debugging"
727
728menu "Memory Debugging"
729
730source "mm/Kconfig.debug"
731
732config DEBUG_OBJECTS
733	bool "Debug object operations"
734	depends on DEBUG_KERNEL
735	help
736	  If you say Y here, additional code will be inserted into the
737	  kernel to track the life time of various objects and validate
738	  the operations on those objects.
739
740config DEBUG_OBJECTS_SELFTEST
741	bool "Debug objects selftest"
742	depends on DEBUG_OBJECTS
743	help
744	  This enables the selftest of the object debug code.
745
746config DEBUG_OBJECTS_FREE
747	bool "Debug objects in freed memory"
748	depends on DEBUG_OBJECTS
749	help
750	  This enables checks whether a k/v free operation frees an area
751	  which contains an object which has not been deactivated
752	  properly. This can make kmalloc/kfree-intensive workloads
753	  much slower.
754
755config DEBUG_OBJECTS_TIMERS
756	bool "Debug timer objects"
757	depends on DEBUG_OBJECTS
758	help
759	  If you say Y here, additional code will be inserted into the
760	  timer routines to track the life time of timer objects and
761	  validate the timer operations.
762
763config DEBUG_OBJECTS_WORK
764	bool "Debug work objects"
765	depends on DEBUG_OBJECTS
766	help
767	  If you say Y here, additional code will be inserted into the
768	  work queue routines to track the life time of work objects and
769	  validate the work operations.
770
771config DEBUG_OBJECTS_RCU_HEAD
772	bool "Debug RCU callbacks objects"
773	depends on DEBUG_OBJECTS
774	help
775	  Enable this to turn on debugging of RCU list heads (call_rcu() usage).
776
777config DEBUG_OBJECTS_PERCPU_COUNTER
778	bool "Debug percpu counter objects"
779	depends on DEBUG_OBJECTS
780	help
781	  If you say Y here, additional code will be inserted into the
782	  percpu counter routines to track the life time of percpu counter
783	  objects and validate the percpu counter operations.
784
785config DEBUG_OBJECTS_ENABLE_DEFAULT
786	int "debug_objects bootup default value (0-1)"
787	range 0 1
788	default "1"
789	depends on DEBUG_OBJECTS
790	help
791	  Debug objects boot parameter default value
792
793config SHRINKER_DEBUG
794	bool "Enable shrinker debugging support"
795	depends on DEBUG_FS
796	help
797	  Say Y to enable the shrinker debugfs interface which provides
798	  visibility into the kernel memory shrinkers subsystem.
799	  Disable it to avoid an extra memory footprint.
800
801config DEBUG_STACK_USAGE
802	bool "Stack utilization instrumentation"
803	depends on DEBUG_KERNEL
804	help
805	  Enables the display of the minimum amount of free stack which each
806	  task has ever had available in the sysrq-T and sysrq-P debug output.
807	  Also emits a message to dmesg when a process exits if that process
808	  used more stack space than previously exiting processes.
809
810	  This option will slow down process creation somewhat.
811
812config SCHED_STACK_END_CHECK
813	bool "Detect stack corruption on calls to schedule()"
814	depends on DEBUG_KERNEL
815	default n
816	help
817	  This option checks for a stack overrun on calls to schedule().
818	  If the stack end location is found to be over written always panic as
819	  the content of the corrupted region can no longer be trusted.
820	  This is to ensure no erroneous behaviour occurs which could result in
821	  data corruption or a sporadic crash at a later stage once the region
822	  is examined. The runtime overhead introduced is minimal.
823
824config ARCH_HAS_DEBUG_VM_PGTABLE
825	bool
826	help
827	  An architecture should select this when it can successfully
828	  build and run DEBUG_VM_PGTABLE.
829
830config DEBUG_VFS
831	bool "Debug VFS"
832	depends on DEBUG_KERNEL
833	help
834	  Enable this to turn on extended checks in the VFS layer that may impact
835	  performance.
836
837	  If unsure, say N.
838
839config DEBUG_VM_IRQSOFF
840	def_bool DEBUG_VM && !PREEMPT_RT
841
842config DEBUG_VM
843	bool "Debug VM"
844	depends on DEBUG_KERNEL
845	help
846	  Enable this to turn on extended checks in the virtual-memory system
847	  that may impact performance.
848
849	  If unsure, say N.
850
851config DEBUG_VM_SHOOT_LAZIES
852	bool "Debug MMU_LAZY_TLB_SHOOTDOWN implementation"
853	depends on DEBUG_VM
854	depends on MMU_LAZY_TLB_SHOOTDOWN
855	help
856	  Enable additional IPIs that ensure lazy tlb mm references are removed
857	  before the mm is freed.
858
859	  If unsure, say N.
860
861config DEBUG_VM_MAPLE_TREE
862	bool "Debug VM maple trees"
863	depends on DEBUG_VM
864	select DEBUG_MAPLE_TREE
865	help
866	  Enable VM maple tree debugging information and extra validations.
867
868	  If unsure, say N.
869
870config DEBUG_VM_RB
871	bool "Debug VM red-black trees"
872	depends on DEBUG_VM
873	help
874	  Enable VM red-black tree debugging information and extra validations.
875
876	  If unsure, say N.
877
878config DEBUG_VM_PGFLAGS
879	bool "Debug page-flags operations"
880	depends on DEBUG_VM
881	help
882	  Enables extra validation on page flags operations.
883
884	  If unsure, say N.
885
886config DEBUG_VM_PGTABLE
887	bool "Debug arch page table for semantics compliance"
888	depends on MMU
889	depends on ARCH_HAS_DEBUG_VM_PGTABLE
890	default y if DEBUG_VM
891	help
892	  This option provides a debug method which can be used to test
893	  architecture page table helper functions on various platforms in
894	  verifying if they comply with expected generic MM semantics. This
895	  will help architecture code in making sure that any changes or
896	  new additions of these helpers still conform to expected
897	  semantics of the generic MM. Platforms will have to opt in for
898	  this through ARCH_HAS_DEBUG_VM_PGTABLE.
899
900	  If unsure, say N.
901
902config ARCH_HAS_DEBUG_VIRTUAL
903	bool
904
905config DEBUG_VIRTUAL
906	bool "Debug VM translations"
907	depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
908	help
909	  Enable some costly sanity checks in virtual to page code. This can
910	  catch mistakes with virt_to_page() and friends.
911
912	  If unsure, say N.
913
914config DEBUG_NOMMU_REGIONS
915	bool "Debug the global anon/private NOMMU mapping region tree"
916	depends on DEBUG_KERNEL && !MMU
917	help
918	  This option causes the global tree of anonymous and private mapping
919	  regions to be regularly checked for invalid topology.
920
921config DEBUG_MEMORY_INIT
922	bool "Debug memory initialisation" if EXPERT
923	default !EXPERT
924	help
925	  Enable this for additional checks during memory initialisation.
926	  The sanity checks verify aspects of the VM such as the memory model
927	  and other information provided by the architecture. Verbose
928	  information will be printed at KERN_DEBUG loglevel depending
929	  on the mminit_loglevel= command-line option.
930
931	  If unsure, say Y
932
933config MEMORY_NOTIFIER_ERROR_INJECT
934	tristate "Memory hotplug notifier error injection module"
935	depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
936	help
937	  This option provides the ability to inject artificial errors to
938	  memory hotplug notifier chain callbacks.  It is controlled through
939	  debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
940
941	  If the notifier call chain should be failed with some events
942	  notified, write the error code to "actions/<notifier event>/error".
943
944	  Example: Inject memory hotplug offline error (-12 == -ENOMEM)
945
946	  # cd /sys/kernel/debug/notifier-error-inject/memory
947	  # echo -12 > actions/MEM_GOING_OFFLINE/error
948	  # echo offline > /sys/devices/system/memory/memoryXXX/state
949	  bash: echo: write error: Cannot allocate memory
950
951	  To compile this code as a module, choose M here: the module will
952	  be called memory-notifier-error-inject.
953
954	  If unsure, say N.
955
956config DEBUG_PER_CPU_MAPS
957	bool "Debug access to per_cpu maps"
958	depends on DEBUG_KERNEL
959	depends on SMP
960	help
961	  Say Y to verify that the per_cpu map being accessed has
962	  been set up. This adds a fair amount of code to kernel memory
963	  and decreases performance.
964
965	  Say N if unsure.
966
967config DEBUG_KMAP_LOCAL
968	bool "Debug kmap_local temporary mappings"
969	depends on DEBUG_KERNEL && KMAP_LOCAL
970	help
971	  This option enables additional error checking for the kmap_local
972	  infrastructure.  Disable for production use.
973
974config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
975	bool
976
977config DEBUG_KMAP_LOCAL_FORCE_MAP
978	bool "Enforce kmap_local temporary mappings"
979	depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
980	select KMAP_LOCAL
981	select DEBUG_KMAP_LOCAL
982	help
983	  This option enforces temporary mappings through the kmap_local
984	  mechanism for non-highmem pages and on non-highmem systems.
985	  Disable this for production systems!
986
987config DEBUG_HIGHMEM
988	bool "Highmem debugging"
989	depends on DEBUG_KERNEL && HIGHMEM
990	select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
991	select DEBUG_KMAP_LOCAL
992	help
993	  This option enables additional error checking for high memory
994	  systems.  Disable for production systems.
995
996config HAVE_DEBUG_STACKOVERFLOW
997	bool
998
999config DEBUG_STACKOVERFLOW
1000	bool "Check for stack overflows"
1001	depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
1002	help
1003	  Say Y here if you want to check for overflows of kernel, IRQ
1004	  and exception stacks (if your architecture uses them). This
1005	  option will show detailed messages if free stack space drops
1006	  below a certain limit.
1007
1008	  These kinds of bugs usually occur when call-chains in the
1009	  kernel get too deep, especially when interrupts are
1010	  involved.
1011
1012	  Use this in cases where you see apparently random memory
1013	  corruption, especially if it appears in 'struct thread_info'
1014
1015	  If in doubt, say "N".
1016
1017config CODE_TAGGING
1018	bool
1019	select KALLSYMS
1020
1021config MEM_ALLOC_PROFILING
1022	bool "Enable memory allocation profiling"
1023	default n
1024	depends on MMU
1025	depends on PROC_FS
1026	depends on !DEBUG_FORCE_WEAK_PER_CPU
1027	select CODE_TAGGING
1028	select PAGE_EXTENSION
1029	select SLAB_OBJ_EXT
1030	help
1031	  Track allocation source code and record total allocation size
1032	  initiated at that code location. The mechanism can be used to track
1033	  memory leaks with a low performance and memory impact.
1034
1035config MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
1036	bool "Enable memory allocation profiling by default"
1037	default y
1038	depends on MEM_ALLOC_PROFILING
1039
1040config MEM_ALLOC_PROFILING_DEBUG
1041	bool "Memory allocation profiler debugging"
1042	default n
1043	depends on MEM_ALLOC_PROFILING
1044	select MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
1045	help
1046	  Adds warnings with helpful error messages for memory allocation
1047	  profiling.
1048
1049source "lib/Kconfig.kasan"
1050source "lib/Kconfig.kfence"
1051source "lib/Kconfig.kmsan"
1052
1053endmenu # "Memory Debugging"
1054
1055config DEBUG_SHIRQ
1056	bool "Debug shared IRQ handlers"
1057	depends on DEBUG_KERNEL
1058	help
1059	  Enable this to generate a spurious interrupt just before a shared
1060	  interrupt handler is deregistered (generating one when registering
1061	  is currently disabled). Drivers need to handle this correctly. Some
1062	  don't and need to be caught.
1063
1064menu "Debug Oops, Lockups and Hangs"
1065
1066config PANIC_ON_OOPS
1067	bool "Panic on Oops"
1068	help
1069	  Say Y here to enable the kernel to panic when it oopses. This
1070	  has the same effect as setting oops=panic on the kernel command
1071	  line.
1072
1073	  This feature is useful to ensure that the kernel does not do
1074	  anything erroneous after an oops which could result in data
1075	  corruption or other issues.
1076
1077	  Say N if unsure.
1078
1079config PANIC_TIMEOUT
1080	int "panic timeout"
1081	default 0
1082	help
1083	  Set the timeout value (in seconds) until a reboot occurs when
1084	  the kernel panics. If n = 0, then we wait forever. A timeout
1085	  value n > 0 will wait n seconds before rebooting, while a timeout
1086	  value n < 0 will reboot immediately. This setting can be overridden
1087	  with the kernel command line option panic=, and from userspace via
1088	  /proc/sys/kernel/panic.
1089
1090config LOCKUP_DETECTOR
1091	bool
1092
1093config SOFTLOCKUP_DETECTOR
1094	bool "Detect Soft Lockups"
1095	depends on DEBUG_KERNEL && !S390
1096	select LOCKUP_DETECTOR
1097	help
1098	  Say Y here to enable the kernel to act as a watchdog to detect
1099	  soft lockups.
1100
1101	  Softlockups are bugs that cause the kernel to loop in kernel
1102	  mode for more than 20 seconds, without giving other tasks a
1103	  chance to run.  The current stack trace is displayed upon
1104	  detection and the system will stay locked up.
1105
1106config SOFTLOCKUP_DETECTOR_INTR_STORM
1107	bool "Detect Interrupt Storm in Soft Lockups"
1108	depends on SOFTLOCKUP_DETECTOR && IRQ_TIME_ACCOUNTING
1109	select GENERIC_IRQ_STAT_SNAPSHOT
1110	default y if NR_CPUS <= 128
1111	help
1112	  Say Y here to enable the kernel to detect interrupt storm
1113	  during "soft lockups".
1114
1115	  "soft lockups" can be caused by a variety of reasons. If one is
1116	  caused by an interrupt storm, then the storming interrupts will not
1117	  be on the callstack. To detect this case, it is necessary to report
1118	  the CPU stats and the interrupt counts during the "soft lockups".
1119
1120config BOOTPARAM_SOFTLOCKUP_PANIC
1121	bool "Panic (Reboot) On Soft Lockups"
1122	depends on SOFTLOCKUP_DETECTOR
1123	help
1124	  Say Y here to enable the kernel to panic on "soft lockups",
1125	  which are bugs that cause the kernel to loop in kernel
1126	  mode for more than 20 seconds (configurable using the watchdog_thresh
1127	  sysctl), without giving other tasks a chance to run.
1128
1129	  The panic can be used in combination with panic_timeout,
1130	  to cause the system to reboot automatically after a
1131	  lockup has been detected. This feature is useful for
1132	  high-availability systems that have uptime guarantees and
1133	  where a lockup must be resolved ASAP.
1134
1135	  Say N if unsure.
1136
1137config HAVE_HARDLOCKUP_DETECTOR_BUDDY
1138	bool
1139	depends on SMP
1140	default y
1141
1142#
1143# Global switch whether to build a hardlockup detector at all. It is available
1144# only when the architecture supports at least one implementation. There are
1145# two exceptions. The hardlockup detector is never enabled on:
1146#
1147#	s390: it reported many false positives there
1148#
1149#	sparc64: has a custom implementation which is not using the common
1150#		hardlockup command line options and sysctl interface.
1151#
1152config HARDLOCKUP_DETECTOR
1153	bool "Detect Hard Lockups"
1154	depends on DEBUG_KERNEL && !S390 && !HARDLOCKUP_DETECTOR_SPARC64
1155	depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_BUDDY || HAVE_HARDLOCKUP_DETECTOR_ARCH
1156	imply HARDLOCKUP_DETECTOR_PERF
1157	imply HARDLOCKUP_DETECTOR_BUDDY
1158	imply HARDLOCKUP_DETECTOR_ARCH
1159	select LOCKUP_DETECTOR
1160
1161	help
1162	  Say Y here to enable the kernel to act as a watchdog to detect
1163	  hard lockups.
1164
1165	  Hardlockups are bugs that cause the CPU to loop in kernel mode
1166	  for more than 10 seconds, without letting other interrupts have a
1167	  chance to run.  The current stack trace is displayed upon detection
1168	  and the system will stay locked up.
1169
1170#
1171# Note that arch-specific variants are always preferred.
1172#
1173config HARDLOCKUP_DETECTOR_PREFER_BUDDY
1174	bool "Prefer the buddy CPU hardlockup detector"
1175	depends on HARDLOCKUP_DETECTOR
1176	depends on HAVE_HARDLOCKUP_DETECTOR_PERF && HAVE_HARDLOCKUP_DETECTOR_BUDDY
1177	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1178	help
1179	  Say Y here to prefer the buddy hardlockup detector over the perf one.
1180
1181	  With the buddy detector, each CPU uses its softlockup hrtimer
1182	  to check that the next CPU is processing hrtimer interrupts by
1183	  verifying that a counter is increasing.
1184
1185	  This hardlockup detector is useful on systems that don't have
1186	  an arch-specific hardlockup detector or if resources needed
1187	  for the hardlockup detector are better used for other things.
1188
1189config HARDLOCKUP_DETECTOR_PERF
1190	bool
1191	depends on HARDLOCKUP_DETECTOR
1192	depends on HAVE_HARDLOCKUP_DETECTOR_PERF && !HARDLOCKUP_DETECTOR_PREFER_BUDDY
1193	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1194	select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1195
1196config HARDLOCKUP_DETECTOR_BUDDY
1197	bool
1198	depends on HARDLOCKUP_DETECTOR
1199	depends on HAVE_HARDLOCKUP_DETECTOR_BUDDY
1200	depends on !HAVE_HARDLOCKUP_DETECTOR_PERF || HARDLOCKUP_DETECTOR_PREFER_BUDDY
1201	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1202	select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1203
1204config HARDLOCKUP_DETECTOR_ARCH
1205	bool
1206	depends on HARDLOCKUP_DETECTOR
1207	depends on HAVE_HARDLOCKUP_DETECTOR_ARCH
1208	help
1209	  The arch-specific implementation of the hardlockup detector will
1210	  be used.
1211
1212#
1213# Both the "perf" and "buddy" hardlockup detectors count hrtimer
1214# interrupts. This config enables functions managing this common code.
1215#
1216config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1217	bool
1218	select SOFTLOCKUP_DETECTOR
1219
1220#
1221# Enables a timestamp based low pass filter to compensate for perf based
1222# hard lockup detection which runs too fast due to turbo modes.
1223#
1224config HARDLOCKUP_CHECK_TIMESTAMP
1225	bool
1226
1227config BOOTPARAM_HARDLOCKUP_PANIC
1228	bool "Panic (Reboot) On Hard Lockups"
1229	depends on HARDLOCKUP_DETECTOR
1230	help
1231	  Say Y here to enable the kernel to panic on "hard lockups",
1232	  which are bugs that cause the kernel to loop in kernel
1233	  mode with interrupts disabled for more than 10 seconds (configurable
1234	  using the watchdog_thresh sysctl).
1235
1236	  Say N if unsure.
1237
1238config DETECT_HUNG_TASK
1239	bool "Detect Hung Tasks"
1240	depends on DEBUG_KERNEL
1241	default SOFTLOCKUP_DETECTOR
1242	help
1243	  Say Y here to enable the kernel to detect "hung tasks",
1244	  which are bugs that cause the task to be stuck in
1245	  uninterruptible "D" state indefinitely.
1246
1247	  When a hung task is detected, the kernel will print the
1248	  current stack trace (which you should report), but the
1249	  task will stay in uninterruptible state. If lockdep is
1250	  enabled then all held locks will also be reported. This
1251	  feature has negligible overhead.
1252
1253config DEFAULT_HUNG_TASK_TIMEOUT
1254	int "Default timeout for hung task detection (in seconds)"
1255	depends on DETECT_HUNG_TASK
1256	default 120
1257	help
1258	  This option controls the default timeout (in seconds) used
1259	  to determine when a task has become non-responsive and should
1260	  be considered hung.
1261
1262	  It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1263	  sysctl or by writing a value to
1264	  /proc/sys/kernel/hung_task_timeout_secs.
1265
1266	  A timeout of 0 disables the check.  The default is two minutes.
1267	  Keeping the default should be fine in most cases.
1268
1269config BOOTPARAM_HUNG_TASK_PANIC
1270	bool "Panic (Reboot) On Hung Tasks"
1271	depends on DETECT_HUNG_TASK
1272	help
1273	  Say Y here to enable the kernel to panic on "hung tasks",
1274	  which are bugs that cause the kernel to leave a task stuck
1275	  in uninterruptible "D" state.
1276
1277	  The panic can be used in combination with panic_timeout,
1278	  to cause the system to reboot automatically after a
1279	  hung task has been detected. This feature is useful for
1280	  high-availability systems that have uptime guarantees and
1281	  where a hung tasks must be resolved ASAP.
1282
1283	  Say N if unsure.
1284
1285config DETECT_HUNG_TASK_BLOCKER
1286	bool "Dump Hung Tasks Blocker"
1287	depends on DETECT_HUNG_TASK
1288	depends on !PREEMPT_RT
1289	default y
1290	help
1291	  Say Y here to show the blocker task's stacktrace who acquires
1292	  the mutex lock which "hung tasks" are waiting.
1293	  This will add overhead a bit but shows suspicious tasks and
1294	  call trace if it comes from waiting a mutex.
1295
1296config WQ_WATCHDOG
1297	bool "Detect Workqueue Stalls"
1298	depends on DEBUG_KERNEL
1299	help
1300	  Say Y here to enable stall detection on workqueues.  If a
1301	  worker pool doesn't make forward progress on a pending work
1302	  item for over a given amount of time, 30s by default, a
1303	  warning message is printed along with dump of workqueue
1304	  state.  This can be configured through kernel parameter
1305	  "workqueue.watchdog_thresh" and its sysfs counterpart.
1306
1307config WQ_CPU_INTENSIVE_REPORT
1308	bool "Report per-cpu work items which hog CPU for too long"
1309	depends on DEBUG_KERNEL
1310	help
1311	  Say Y here to enable reporting of concurrency-managed per-cpu work
1312	  items that hog CPUs for longer than
1313	  workqueue.cpu_intensive_thresh_us. Workqueue automatically
1314	  detects and excludes them from concurrency management to prevent
1315	  them from stalling other per-cpu work items. Occassional
1316	  triggering may not necessarily indicate a problem. Repeated
1317	  triggering likely indicates that the work item should be switched
1318	  to use an unbound workqueue.
1319
1320config TEST_LOCKUP
1321	tristate "Test module to generate lockups"
1322	depends on m
1323	help
1324	  This builds the "test_lockup" module that helps to make sure
1325	  that watchdogs and lockup detectors are working properly.
1326
1327	  Depending on module parameters it could emulate soft or hard
1328	  lockup, "hung task", or locking arbitrary lock for a long time.
1329	  Also it could generate series of lockups with cooling-down periods.
1330
1331	  If unsure, say N.
1332
1333endmenu # "Debug lockups and hangs"
1334
1335menu "Scheduler Debugging"
1336
1337config SCHED_INFO
1338	bool
1339	default n
1340
1341config SCHEDSTATS
1342	bool "Collect scheduler statistics"
1343	depends on PROC_FS
1344	select SCHED_INFO
1345	help
1346	  If you say Y here, additional code will be inserted into the
1347	  scheduler and related routines to collect statistics about
1348	  scheduler behavior and provide them in /proc/schedstat.  These
1349	  stats may be useful for both tuning and debugging the scheduler
1350	  If you aren't debugging the scheduler or trying to tune a specific
1351	  application, you can say N to avoid the very slight overhead
1352	  this adds.
1353
1354endmenu
1355
1356config DEBUG_PREEMPT
1357	bool "Debug preemptible kernel"
1358	depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1359	help
1360	  If you say Y here then the kernel will use a debug variant of the
1361	  commonly used smp_processor_id() function and will print warnings
1362	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
1363	  will detect preemption count underflows.
1364
1365	  This option has potential to introduce high runtime overhead,
1366	  depending on workload as it triggers debugging routines for each
1367	  this_cpu operation. It should only be used for debugging purposes.
1368
1369menu "Lock Debugging (spinlocks, mutexes, etc...)"
1370
1371config LOCK_DEBUGGING_SUPPORT
1372	bool
1373	depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1374	default y
1375
1376config PROVE_LOCKING
1377	bool "Lock debugging: prove locking correctness"
1378	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1379	select LOCKDEP
1380	select DEBUG_SPINLOCK
1381	select DEBUG_MUTEXES if !PREEMPT_RT
1382	select DEBUG_RT_MUTEXES if RT_MUTEXES
1383	select DEBUG_RWSEMS if !PREEMPT_RT
1384	select DEBUG_WW_MUTEX_SLOWPATH
1385	select DEBUG_LOCK_ALLOC
1386	select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1387	select TRACE_IRQFLAGS
1388	default n
1389	help
1390	 This feature enables the kernel to prove that all locking
1391	 that occurs in the kernel runtime is mathematically
1392	 correct: that under no circumstance could an arbitrary (and
1393	 not yet triggered) combination of observed locking
1394	 sequences (on an arbitrary number of CPUs, running an
1395	 arbitrary number of tasks and interrupt contexts) cause a
1396	 deadlock.
1397
1398	 In short, this feature enables the kernel to report locking
1399	 related deadlocks before they actually occur.
1400
1401	 The proof does not depend on how hard and complex a
1402	 deadlock scenario would be to trigger: how many
1403	 participant CPUs, tasks and irq-contexts would be needed
1404	 for it to trigger. The proof also does not depend on
1405	 timing: if a race and a resulting deadlock is possible
1406	 theoretically (no matter how unlikely the race scenario
1407	 is), it will be proven so and will immediately be
1408	 reported by the kernel (once the event is observed that
1409	 makes the deadlock theoretically possible).
1410
1411	 If a deadlock is impossible (i.e. the locking rules, as
1412	 observed by the kernel, are mathematically correct), the
1413	 kernel reports nothing.
1414
1415	 NOTE: this feature can also be enabled for rwlocks, mutexes
1416	 and rwsems - in which case all dependencies between these
1417	 different locking variants are observed and mapped too, and
1418	 the proof of observed correctness is also maintained for an
1419	 arbitrary combination of these separate locking variants.
1420
1421	 For more details, see Documentation/locking/lockdep-design.rst.
1422
1423config PROVE_RAW_LOCK_NESTING
1424	bool "Enable raw_spinlock - spinlock nesting checks" if !ARCH_SUPPORTS_RT
1425	depends on PROVE_LOCKING
1426	default y if ARCH_SUPPORTS_RT
1427	help
1428	 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1429	 that the lock nesting rules for PREEMPT_RT enabled kernels are
1430	 not violated.
1431
1432config LOCK_STAT
1433	bool "Lock usage statistics"
1434	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1435	select LOCKDEP
1436	select DEBUG_SPINLOCK
1437	select DEBUG_MUTEXES if !PREEMPT_RT
1438	select DEBUG_RT_MUTEXES if RT_MUTEXES
1439	select DEBUG_LOCK_ALLOC
1440	default n
1441	help
1442	 This feature enables tracking lock contention points
1443
1444	 For more details, see Documentation/locking/lockstat.rst
1445
1446	 This also enables lock events required by "perf lock",
1447	 subcommand of perf.
1448	 If you want to use "perf lock", you also need to turn on
1449	 CONFIG_EVENT_TRACING.
1450
1451	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1452	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1453
1454config DEBUG_RT_MUTEXES
1455	bool "RT Mutex debugging, deadlock detection"
1456	depends on DEBUG_KERNEL && RT_MUTEXES
1457	help
1458	 This allows rt mutex semantics violations and rt mutex related
1459	 deadlocks (lockups) to be detected and reported automatically.
1460
1461config DEBUG_SPINLOCK
1462	bool "Spinlock and rw-lock debugging: basic checks"
1463	depends on DEBUG_KERNEL
1464	select UNINLINE_SPIN_UNLOCK
1465	help
1466	  Say Y here and build SMP to catch missing spinlock initialization
1467	  and certain other kinds of spinlock errors commonly made.  This is
1468	  best used in conjunction with the NMI watchdog so that spinlock
1469	  deadlocks are also debuggable.
1470
1471config DEBUG_MUTEXES
1472	bool "Mutex debugging: basic checks"
1473	depends on DEBUG_KERNEL && !PREEMPT_RT
1474	help
1475	 This feature allows mutex semantics violations to be detected and
1476	 reported.
1477
1478config DEBUG_WW_MUTEX_SLOWPATH
1479	bool "Wait/wound mutex debugging: Slowpath testing"
1480	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1481	select DEBUG_LOCK_ALLOC
1482	select DEBUG_SPINLOCK
1483	select DEBUG_MUTEXES if !PREEMPT_RT
1484	select DEBUG_RT_MUTEXES if PREEMPT_RT
1485	help
1486	 This feature enables slowpath testing for w/w mutex users by
1487	 injecting additional -EDEADLK wound/backoff cases. Together with
1488	 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1489	 will test all possible w/w mutex interface abuse with the
1490	 exception of simply not acquiring all the required locks.
1491	 Note that this feature can introduce significant overhead, so
1492	 it really should not be enabled in a production or distro kernel,
1493	 even a debug kernel.  If you are a driver writer, enable it.  If
1494	 you are a distro, do not.
1495
1496config DEBUG_RWSEMS
1497	bool "RW Semaphore debugging: basic checks"
1498	depends on DEBUG_KERNEL && !PREEMPT_RT
1499	help
1500	  This debugging feature allows mismatched rw semaphore locks
1501	  and unlocks to be detected and reported.
1502
1503config DEBUG_LOCK_ALLOC
1504	bool "Lock debugging: detect incorrect freeing of live locks"
1505	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1506	select DEBUG_SPINLOCK
1507	select DEBUG_MUTEXES if !PREEMPT_RT
1508	select DEBUG_RT_MUTEXES if RT_MUTEXES
1509	select LOCKDEP
1510	help
1511	 This feature will check whether any held lock (spinlock, rwlock,
1512	 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1513	 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1514	 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1515	 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1516	 held during task exit.
1517
1518config LOCKDEP
1519	bool
1520	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1521	select STACKTRACE
1522	select KALLSYMS
1523	select KALLSYMS_ALL
1524
1525config LOCKDEP_SMALL
1526	bool
1527
1528config LOCKDEP_BITS
1529	int "Size for MAX_LOCKDEP_ENTRIES (as Nth power of 2)"
1530	depends on LOCKDEP && !LOCKDEP_SMALL
1531	range 10 24
1532	default 15
1533	help
1534	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1535
1536config LOCKDEP_CHAINS_BITS
1537	int "Size for MAX_LOCKDEP_CHAINS (as Nth power of 2)"
1538	depends on LOCKDEP && !LOCKDEP_SMALL
1539	range 10 21
1540	default 16
1541	help
1542	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1543
1544config LOCKDEP_STACK_TRACE_BITS
1545	int "Size for MAX_STACK_TRACE_ENTRIES (as Nth power of 2)"
1546	depends on LOCKDEP && !LOCKDEP_SMALL
1547	range 10 26
1548	default 19
1549	help
1550	  Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1551
1552config LOCKDEP_STACK_TRACE_HASH_BITS
1553	int "Size for STACK_TRACE_HASH_SIZE (as Nth power of 2)"
1554	depends on LOCKDEP && !LOCKDEP_SMALL
1555	range 10 26
1556	default 14
1557	help
1558	  Try increasing this value if you need large STACK_TRACE_HASH_SIZE.
1559
1560config LOCKDEP_CIRCULAR_QUEUE_BITS
1561	int "Size for elements in circular_queue struct (as Nth power of 2)"
1562	depends on LOCKDEP
1563	range 10 26
1564	default 12
1565	help
1566	  Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1567
1568config DEBUG_LOCKDEP
1569	bool "Lock dependency engine debugging"
1570	depends on DEBUG_KERNEL && LOCKDEP
1571	select DEBUG_IRQFLAGS
1572	help
1573	  If you say Y here, the lock dependency engine will do
1574	  additional runtime checks to debug itself, at the price
1575	  of more runtime overhead.
1576
1577config DEBUG_ATOMIC_SLEEP
1578	bool "Sleep inside atomic section checking"
1579	select PREEMPT_COUNT
1580	depends on DEBUG_KERNEL
1581	depends on !ARCH_NO_PREEMPT
1582	help
1583	  If you say Y here, various routines which may sleep will become very
1584	  noisy if they are called inside atomic sections: when a spinlock is
1585	  held, inside an rcu read side critical section, inside preempt disabled
1586	  sections, inside an interrupt, etc...
1587
1588config DEBUG_LOCKING_API_SELFTESTS
1589	bool "Locking API boot-time self-tests"
1590	depends on DEBUG_KERNEL
1591	help
1592	  Say Y here if you want the kernel to run a short self-test during
1593	  bootup. The self-test checks whether common types of locking bugs
1594	  are detected by debugging mechanisms or not. (if you disable
1595	  lock debugging then those bugs won't be detected of course.)
1596	  The following locking APIs are covered: spinlocks, rwlocks,
1597	  mutexes and rwsems.
1598
1599config LOCK_TORTURE_TEST
1600	tristate "torture tests for locking"
1601	depends on DEBUG_KERNEL
1602	select TORTURE_TEST
1603	help
1604	  This option provides a kernel module that runs torture tests
1605	  on kernel locking primitives.  The kernel module may be built
1606	  after the fact on the running kernel to be tested, if desired.
1607
1608	  Say Y here if you want kernel locking-primitive torture tests
1609	  to be built into the kernel.
1610	  Say M if you want these torture tests to build as a module.
1611	  Say N if you are unsure.
1612
1613config WW_MUTEX_SELFTEST
1614	tristate "Wait/wound mutex selftests"
1615	help
1616	  This option provides a kernel module that runs tests on the
1617	  on the struct ww_mutex locking API.
1618
1619	  It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1620	  with this test harness.
1621
1622	  Say M if you want these self tests to build as a module.
1623	  Say N if you are unsure.
1624
1625config SCF_TORTURE_TEST
1626	tristate "torture tests for smp_call_function*()"
1627	depends on DEBUG_KERNEL
1628	select TORTURE_TEST
1629	help
1630	  This option provides a kernel module that runs torture tests
1631	  on the smp_call_function() family of primitives.  The kernel
1632	  module may be built after the fact on the running kernel to
1633	  be tested, if desired.
1634
1635config CSD_LOCK_WAIT_DEBUG
1636	bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1637	depends on DEBUG_KERNEL
1638	depends on SMP
1639	depends on 64BIT
1640	default n
1641	help
1642	  This option enables debug prints when CPUs are slow to respond
1643	  to the smp_call_function*() IPI wrappers.  These debug prints
1644	  include the IPI handler function currently executing (if any)
1645	  and relevant stack traces.
1646
1647config CSD_LOCK_WAIT_DEBUG_DEFAULT
1648	bool "Default csd_lock_wait() debugging on at boot time"
1649	depends on CSD_LOCK_WAIT_DEBUG
1650	depends on 64BIT
1651	default n
1652	help
1653	  This option causes the csdlock_debug= kernel boot parameter to
1654	  default to 1 (basic debugging) instead of 0 (no debugging).
1655
1656endmenu # lock debugging
1657
1658config TRACE_IRQFLAGS
1659	depends on TRACE_IRQFLAGS_SUPPORT
1660	bool
1661	help
1662	  Enables hooks to interrupt enabling and disabling for
1663	  either tracing or lock debugging.
1664
1665config TRACE_IRQFLAGS_NMI
1666	def_bool y
1667	depends on TRACE_IRQFLAGS
1668	depends on TRACE_IRQFLAGS_NMI_SUPPORT
1669
1670config NMI_CHECK_CPU
1671	bool "Debugging for CPUs failing to respond to backtrace requests"
1672	depends on DEBUG_KERNEL
1673	depends on X86
1674	default n
1675	help
1676	  Enables debug prints when a CPU fails to respond to a given
1677	  backtrace NMI.  These prints provide some reasons why a CPU
1678	  might legitimately be failing to respond, for example, if it
1679	  is offline of if ignore_nmis is set.
1680
1681config DEBUG_IRQFLAGS
1682	bool "Debug IRQ flag manipulation"
1683	help
1684	  Enables checks for potentially unsafe enabling or disabling of
1685	  interrupts, such as calling raw_local_irq_restore() when interrupts
1686	  are enabled.
1687
1688config STACKTRACE
1689	bool "Stack backtrace support"
1690	depends on STACKTRACE_SUPPORT
1691	help
1692	  This option causes the kernel to create a /proc/pid/stack for
1693	  every process, showing its current stack trace.
1694	  It is also used by various kernel debugging features that require
1695	  stack trace generation.
1696
1697config WARN_ALL_UNSEEDED_RANDOM
1698	bool "Warn for all uses of unseeded randomness"
1699	default n
1700	help
1701	  Some parts of the kernel contain bugs relating to their use of
1702	  cryptographically secure random numbers before it's actually possible
1703	  to generate those numbers securely. This setting ensures that these
1704	  flaws don't go unnoticed, by enabling a message, should this ever
1705	  occur. This will allow people with obscure setups to know when things
1706	  are going wrong, so that they might contact developers about fixing
1707	  it.
1708
1709	  Unfortunately, on some models of some architectures getting
1710	  a fully seeded CRNG is extremely difficult, and so this can
1711	  result in dmesg getting spammed for a surprisingly long
1712	  time.  This is really bad from a security perspective, and
1713	  so architecture maintainers really need to do what they can
1714	  to get the CRNG seeded sooner after the system is booted.
1715	  However, since users cannot do anything actionable to
1716	  address this, by default this option is disabled.
1717
1718	  Say Y here if you want to receive warnings for all uses of
1719	  unseeded randomness.  This will be of use primarily for
1720	  those developers interested in improving the security of
1721	  Linux kernels running on their architecture (or
1722	  subarchitecture).
1723
1724config DEBUG_KOBJECT
1725	bool "kobject debugging"
1726	depends on DEBUG_KERNEL
1727	help
1728	  If you say Y here, some extra kobject debugging messages will be sent
1729	  to the syslog.
1730
1731config DEBUG_KOBJECT_RELEASE
1732	bool "kobject release debugging"
1733	depends on DEBUG_OBJECTS_TIMERS
1734	help
1735	  kobjects are reference counted objects.  This means that their
1736	  last reference count put is not predictable, and the kobject can
1737	  live on past the point at which a driver decides to drop its
1738	  initial reference to the kobject gained on allocation.  An
1739	  example of this would be a struct device which has just been
1740	  unregistered.
1741
1742	  However, some buggy drivers assume that after such an operation,
1743	  the memory backing the kobject can be immediately freed.  This
1744	  goes completely against the principles of a refcounted object.
1745
1746	  If you say Y here, the kernel will delay the release of kobjects
1747	  on the last reference count to improve the visibility of this
1748	  kind of kobject release bug.
1749
1750config HAVE_DEBUG_BUGVERBOSE
1751	bool
1752
1753menu "Debug kernel data structures"
1754
1755config DEBUG_LIST
1756	bool "Debug linked list manipulation"
1757	depends on DEBUG_KERNEL
1758	select LIST_HARDENED
1759	help
1760	  Enable this to turn on extended checks in the linked-list walking
1761	  routines.
1762
1763	  This option trades better quality error reports for performance, and
1764	  is more suitable for kernel debugging. If you care about performance,
1765	  you should only enable CONFIG_LIST_HARDENED instead.
1766
1767	  If unsure, say N.
1768
1769config DEBUG_PLIST
1770	bool "Debug priority linked list manipulation"
1771	depends on DEBUG_KERNEL
1772	help
1773	  Enable this to turn on extended checks in the priority-ordered
1774	  linked-list (plist) walking routines.  This checks the entire
1775	  list multiple times during each manipulation.
1776
1777	  If unsure, say N.
1778
1779config DEBUG_SG
1780	bool "Debug SG table operations"
1781	depends on DEBUG_KERNEL
1782	help
1783	  Enable this to turn on checks on scatter-gather tables. This can
1784	  help find problems with drivers that do not properly initialize
1785	  their sg tables.
1786
1787	  If unsure, say N.
1788
1789config DEBUG_NOTIFIERS
1790	bool "Debug notifier call chains"
1791	depends on DEBUG_KERNEL
1792	help
1793	  Enable this to turn on sanity checking for notifier call chains.
1794	  This is most useful for kernel developers to make sure that
1795	  modules properly unregister themselves from notifier chains.
1796	  This is a relatively cheap check but if you care about maximum
1797	  performance, say N.
1798
1799config DEBUG_CLOSURES
1800	bool "Debug closures (bcache async widgits)"
1801	depends on CLOSURES
1802	select DEBUG_FS
1803	help
1804	  Keeps all active closures in a linked list and provides a debugfs
1805	  interface to list them, which makes it possible to see asynchronous
1806	  operations that get stuck.
1807
1808config DEBUG_MAPLE_TREE
1809	bool "Debug maple trees"
1810	depends on DEBUG_KERNEL
1811	help
1812	  Enable maple tree debugging information and extra validations.
1813
1814	  If unsure, say N.
1815
1816endmenu
1817
1818source "kernel/rcu/Kconfig.debug"
1819
1820config DEBUG_WQ_FORCE_RR_CPU
1821	bool "Force round-robin CPU selection for unbound work items"
1822	depends on DEBUG_KERNEL
1823	default n
1824	help
1825	  Workqueue used to implicitly guarantee that work items queued
1826	  without explicit CPU specified are put on the local CPU.  This
1827	  guarantee is no longer true and while local CPU is still
1828	  preferred work items may be put on foreign CPUs.  Kernel
1829	  parameter "workqueue.debug_force_rr_cpu" is added to force
1830	  round-robin CPU selection to flush out usages which depend on the
1831	  now broken guarantee.  This config option enables the debug
1832	  feature by default.  When enabled, memory and cache locality will
1833	  be impacted.
1834
1835config CPU_HOTPLUG_STATE_CONTROL
1836	bool "Enable CPU hotplug state control"
1837	depends on DEBUG_KERNEL
1838	depends on HOTPLUG_CPU
1839	default n
1840	help
1841	  Allows to write steps between "offline" and "online" to the CPUs
1842	  sysfs target file so states can be stepped granular. This is a debug
1843	  option for now as the hotplug machinery cannot be stopped and
1844	  restarted at arbitrary points yet.
1845
1846	  Say N if your are unsure.
1847
1848config LATENCYTOP
1849	bool "Latency measuring infrastructure"
1850	depends on DEBUG_KERNEL
1851	depends on STACKTRACE_SUPPORT
1852	depends on PROC_FS
1853	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1854	select KALLSYMS
1855	select KALLSYMS_ALL
1856	select STACKTRACE
1857	select SCHEDSTATS
1858	help
1859	  Enable this option if you want to use the LatencyTOP tool
1860	  to find out which userspace is blocking on what kernel operations.
1861
1862config DEBUG_CGROUP_REF
1863	bool "Disable inlining of cgroup css reference count functions"
1864	depends on DEBUG_KERNEL
1865	depends on CGROUPS
1866	depends on KPROBES
1867	default n
1868	help
1869	  Force cgroup css reference count functions to not be inlined so
1870	  that they can be kprobed for debugging.
1871
1872source "kernel/trace/Kconfig"
1873
1874config PROVIDE_OHCI1394_DMA_INIT
1875	bool "Remote debugging over FireWire early on boot"
1876	depends on PCI && X86
1877	help
1878	  If you want to debug problems which hang or crash the kernel early
1879	  on boot and the crashing machine has a FireWire port, you can use
1880	  this feature to remotely access the memory of the crashed machine
1881	  over FireWire. This employs remote DMA as part of the OHCI1394
1882	  specification which is now the standard for FireWire controllers.
1883
1884	  With remote DMA, you can monitor the printk buffer remotely using
1885	  firescope and access all memory below 4GB using fireproxy from gdb.
1886	  Even controlling a kernel debugger is possible using remote DMA.
1887
1888	  Usage:
1889
1890	  If ohci1394_dma=early is used as boot parameter, it will initialize
1891	  all OHCI1394 controllers which are found in the PCI config space.
1892
1893	  As all changes to the FireWire bus such as enabling and disabling
1894	  devices cause a bus reset and thereby disable remote DMA for all
1895	  devices, be sure to have the cable plugged and FireWire enabled on
1896	  the debugging host before booting the debug target for debugging.
1897
1898	  This code (~1k) is freed after boot. By then, the firewire stack
1899	  in charge of the OHCI-1394 controllers should be used instead.
1900
1901	  See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1902
1903source "samples/Kconfig"
1904
1905config ARCH_HAS_DEVMEM_IS_ALLOWED
1906	bool
1907
1908config STRICT_DEVMEM
1909	bool "Filter access to /dev/mem"
1910	depends on MMU && DEVMEM
1911	depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1912	default y if PPC || X86 || ARM64 || S390
1913	help
1914	  If this option is disabled, you allow userspace (root) access to all
1915	  of memory, including kernel and userspace memory. Accidental
1916	  access to this is obviously disastrous, but specific access can
1917	  be used by people debugging the kernel. Note that with PAT support
1918	  enabled, even in this case there are restrictions on /dev/mem
1919	  use due to the cache aliasing requirements.
1920
1921	  If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1922	  file only allows userspace access to PCI space and the BIOS code and
1923	  data regions.  This is sufficient for dosemu and X and all common
1924	  users of /dev/mem.
1925
1926	  If in doubt, say Y.
1927
1928config IO_STRICT_DEVMEM
1929	bool "Filter I/O access to /dev/mem"
1930	depends on STRICT_DEVMEM
1931	help
1932	  If this option is disabled, you allow userspace (root) access to all
1933	  io-memory regardless of whether a driver is actively using that
1934	  range.  Accidental access to this is obviously disastrous, but
1935	  specific access can be used by people debugging kernel drivers.
1936
1937	  If this option is switched on, the /dev/mem file only allows
1938	  userspace access to *idle* io-memory ranges (see /proc/iomem) This
1939	  may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1940	  if the driver using a given range cannot be disabled.
1941
1942	  If in doubt, say Y.
1943
1944menu "$(SRCARCH) Debugging"
1945
1946source "arch/$(SRCARCH)/Kconfig.debug"
1947
1948endmenu
1949
1950menu "Kernel Testing and Coverage"
1951
1952source "lib/kunit/Kconfig"
1953
1954config NOTIFIER_ERROR_INJECTION
1955	tristate "Notifier error injection"
1956	depends on DEBUG_KERNEL
1957	select DEBUG_FS
1958	help
1959	  This option provides the ability to inject artificial errors to
1960	  specified notifier chain callbacks. It is useful to test the error
1961	  handling of notifier call chain failures.
1962
1963	  Say N if unsure.
1964
1965config PM_NOTIFIER_ERROR_INJECT
1966	tristate "PM notifier error injection module"
1967	depends on PM && NOTIFIER_ERROR_INJECTION
1968	default m if PM_DEBUG
1969	help
1970	  This option provides the ability to inject artificial errors to
1971	  PM notifier chain callbacks.  It is controlled through debugfs
1972	  interface /sys/kernel/debug/notifier-error-inject/pm
1973
1974	  If the notifier call chain should be failed with some events
1975	  notified, write the error code to "actions/<notifier event>/error".
1976
1977	  Example: Inject PM suspend error (-12 = -ENOMEM)
1978
1979	  # cd /sys/kernel/debug/notifier-error-inject/pm/
1980	  # echo -12 > actions/PM_SUSPEND_PREPARE/error
1981	  # echo mem > /sys/power/state
1982	  bash: echo: write error: Cannot allocate memory
1983
1984	  To compile this code as a module, choose M here: the module will
1985	  be called pm-notifier-error-inject.
1986
1987	  If unsure, say N.
1988
1989config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1990	tristate "OF reconfig notifier error injection module"
1991	depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1992	help
1993	  This option provides the ability to inject artificial errors to
1994	  OF reconfig notifier chain callbacks.  It is controlled
1995	  through debugfs interface under
1996	  /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1997
1998	  If the notifier call chain should be failed with some events
1999	  notified, write the error code to "actions/<notifier event>/error".
2000
2001	  To compile this code as a module, choose M here: the module will
2002	  be called of-reconfig-notifier-error-inject.
2003
2004	  If unsure, say N.
2005
2006config NETDEV_NOTIFIER_ERROR_INJECT
2007	tristate "Netdev notifier error injection module"
2008	depends on NET && NOTIFIER_ERROR_INJECTION
2009	help
2010	  This option provides the ability to inject artificial errors to
2011	  netdevice notifier chain callbacks.  It is controlled through debugfs
2012	  interface /sys/kernel/debug/notifier-error-inject/netdev
2013
2014	  If the notifier call chain should be failed with some events
2015	  notified, write the error code to "actions/<notifier event>/error".
2016
2017	  Example: Inject netdevice mtu change error (-22 = -EINVAL)
2018
2019	  # cd /sys/kernel/debug/notifier-error-inject/netdev
2020	  # echo -22 > actions/NETDEV_CHANGEMTU/error
2021	  # ip link set eth0 mtu 1024
2022	  RTNETLINK answers: Invalid argument
2023
2024	  To compile this code as a module, choose M here: the module will
2025	  be called netdev-notifier-error-inject.
2026
2027	  If unsure, say N.
2028
2029config FUNCTION_ERROR_INJECTION
2030	bool "Fault-injections of functions"
2031	depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
2032	help
2033	  Add fault injections into various functions that are annotated with
2034	  ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
2035	  value of these functions. This is useful to test error paths of code.
2036
2037	  If unsure, say N
2038
2039config FAULT_INJECTION
2040	bool "Fault-injection framework"
2041	depends on DEBUG_KERNEL
2042	help
2043	  Provide fault-injection framework.
2044	  For more details, see Documentation/fault-injection/.
2045
2046config FAILSLAB
2047	bool "Fault-injection capability for kmalloc"
2048	depends on FAULT_INJECTION
2049	help
2050	  Provide fault-injection capability for kmalloc.
2051
2052config FAIL_PAGE_ALLOC
2053	bool "Fault-injection capability for alloc_pages()"
2054	depends on FAULT_INJECTION
2055	help
2056	  Provide fault-injection capability for alloc_pages().
2057
2058config FAULT_INJECTION_USERCOPY
2059	bool "Fault injection capability for usercopy functions"
2060	depends on FAULT_INJECTION
2061	help
2062	  Provides fault-injection capability to inject failures
2063	  in usercopy functions (copy_from_user(), get_user(), ...).
2064
2065config FAIL_MAKE_REQUEST
2066	bool "Fault-injection capability for disk IO"
2067	depends on FAULT_INJECTION && BLOCK
2068	help
2069	  Provide fault-injection capability for disk IO.
2070
2071config FAIL_IO_TIMEOUT
2072	bool "Fault-injection capability for faking disk interrupts"
2073	depends on FAULT_INJECTION && BLOCK
2074	help
2075	  Provide fault-injection capability on end IO handling. This
2076	  will make the block layer "forget" an interrupt as configured,
2077	  thus exercising the error handling.
2078
2079	  Only works with drivers that use the generic timeout handling,
2080	  for others it won't do anything.
2081
2082config FAIL_FUTEX
2083	bool "Fault-injection capability for futexes"
2084	select DEBUG_FS
2085	depends on FAULT_INJECTION && FUTEX
2086	help
2087	  Provide fault-injection capability for futexes.
2088
2089config FAULT_INJECTION_DEBUG_FS
2090	bool "Debugfs entries for fault-injection capabilities"
2091	depends on FAULT_INJECTION && SYSFS && DEBUG_FS
2092	help
2093	  Enable configuration of fault-injection capabilities via debugfs.
2094
2095config FAIL_FUNCTION
2096	bool "Fault-injection capability for functions"
2097	depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
2098	help
2099	  Provide function-based fault-injection capability.
2100	  This will allow you to override a specific function with a return
2101	  with given return value. As a result, function caller will see
2102	  an error value and have to handle it. This is useful to test the
2103	  error handling in various subsystems.
2104
2105config FAIL_MMC_REQUEST
2106	bool "Fault-injection capability for MMC IO"
2107	depends on FAULT_INJECTION_DEBUG_FS && MMC
2108	help
2109	  Provide fault-injection capability for MMC IO.
2110	  This will make the mmc core return data errors. This is
2111	  useful to test the error handling in the mmc block device
2112	  and to test how the mmc host driver handles retries from
2113	  the block device.
2114
2115config FAIL_SUNRPC
2116	bool "Fault-injection capability for SunRPC"
2117	depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2118	help
2119	  Provide fault-injection capability for SunRPC and
2120	  its consumers.
2121
2122config FAIL_SKB_REALLOC
2123	bool "Fault-injection capability forcing skb to reallocate"
2124	depends on FAULT_INJECTION_DEBUG_FS
2125	help
2126	  Provide fault-injection capability that forces the skb to be
2127	  reallocated, catching possible invalid pointers to the skb.
2128
2129	  For more information, check
2130	  Documentation/fault-injection/fault-injection.rst
2131
2132config FAULT_INJECTION_CONFIGFS
2133	bool "Configfs interface for fault-injection capabilities"
2134	depends on FAULT_INJECTION
2135	select CONFIGFS_FS
2136	help
2137	  This option allows configfs-based drivers to dynamically configure
2138	  fault-injection via configfs.  Each parameter for driver-specific
2139	  fault-injection can be made visible as a configfs attribute in a
2140	  configfs group.
2141
2142
2143config FAULT_INJECTION_STACKTRACE_FILTER
2144	bool "stacktrace filter for fault-injection capabilities"
2145	depends on FAULT_INJECTION
2146	depends on (FAULT_INJECTION_DEBUG_FS || FAULT_INJECTION_CONFIGFS) && STACKTRACE_SUPPORT
2147	select STACKTRACE
2148	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2149	help
2150	  Provide stacktrace filter for fault-injection capabilities
2151
2152config ARCH_HAS_KCOV
2153	bool
2154	help
2155	  An architecture should select this when it can successfully
2156	  build and run with CONFIG_KCOV. This typically requires
2157	  disabling instrumentation for some early boot code.
2158
2159config KCOV
2160	bool "Code coverage for fuzzing"
2161	depends on ARCH_HAS_KCOV
2162	depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2163		   GCC_VERSION >= 120000 || CC_IS_CLANG
2164	select DEBUG_FS
2165	select OBJTOOL if HAVE_NOINSTR_HACK
2166	help
2167	  KCOV exposes kernel code coverage information in a form suitable
2168	  for coverage-guided fuzzing (randomized testing).
2169
2170	  For more details, see Documentation/dev-tools/kcov.rst.
2171
2172config KCOV_ENABLE_COMPARISONS
2173	bool "Enable comparison operands collection by KCOV"
2174	depends on KCOV
2175	depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2176	help
2177	  KCOV also exposes operands of every comparison in the instrumented
2178	  code along with operand sizes and PCs of the comparison instructions.
2179	  These operands can be used by fuzzing engines to improve the quality
2180	  of fuzzing coverage.
2181
2182config KCOV_INSTRUMENT_ALL
2183	bool "Instrument all code by default"
2184	depends on KCOV
2185	default y
2186	help
2187	  If you are doing generic system call fuzzing (like e.g. syzkaller),
2188	  then you will want to instrument the whole kernel and you should
2189	  say y here. If you are doing more targeted fuzzing (like e.g.
2190	  filesystem fuzzing with AFL) then you will want to enable coverage
2191	  for more specific subsets of files, and should say n here.
2192
2193config KCOV_IRQ_AREA_SIZE
2194	hex "Size of interrupt coverage collection area in words"
2195	depends on KCOV
2196	default 0x40000
2197	help
2198	  KCOV uses preallocated per-cpu areas to collect coverage from
2199	  soft interrupts. This specifies the size of those areas in the
2200	  number of unsigned long words.
2201
2202config KCOV_SELFTEST
2203	bool "Perform short selftests on boot"
2204	depends on KCOV
2205	help
2206	  Run short KCOV coverage collection selftests on boot.
2207	  On test failure, causes the kernel to panic. Recommended to be
2208	  enabled, ensuring critical functionality works as intended.
2209
2210menuconfig RUNTIME_TESTING_MENU
2211	bool "Runtime Testing"
2212	default y
2213
2214if RUNTIME_TESTING_MENU
2215
2216config TEST_DHRY
2217	tristate "Dhrystone benchmark test"
2218	help
2219	  Enable this to include the Dhrystone 2.1 benchmark.  This test
2220	  calculates the number of Dhrystones per second, and the number of
2221	  DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided
2222	  by 1757 (the number of Dhrystones per second obtained on the VAX
2223	  11/780, nominally a 1 MIPS machine).
2224
2225	  To run the benchmark, it needs to be enabled explicitly, either from
2226	  the kernel command line (when built-in), or from userspace (when
2227	  built-in or modular).
2228
2229	  Run once during kernel boot:
2230
2231	      test_dhry.run
2232
2233	  Set number of iterations from kernel command line:
2234
2235	      test_dhry.iterations=<n>
2236
2237	  Set number of iterations from userspace:
2238
2239	      echo <n> > /sys/module/test_dhry/parameters/iterations
2240
2241	  Trigger manual run from userspace:
2242
2243	      echo y > /sys/module/test_dhry/parameters/run
2244
2245	  If the number of iterations is <= 0, the test will devise a suitable
2246	  number of iterations (test runs for at least 2s) automatically.
2247	  This process takes ca. 4s.
2248
2249	  If unsure, say N.
2250
2251config LKDTM
2252	tristate "Linux Kernel Dump Test Tool Module"
2253	depends on DEBUG_FS
2254	help
2255	This module enables testing of the different dumping mechanisms by
2256	inducing system failures at predefined crash points.
2257	If you don't need it: say N
2258	Choose M here to compile this code as a module. The module will be
2259	called lkdtm.
2260
2261	Documentation on how to use the module can be found in
2262	Documentation/fault-injection/provoke-crashes.rst
2263
2264config CPUMASK_KUNIT_TEST
2265	tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2266	depends on KUNIT
2267	default KUNIT_ALL_TESTS
2268	help
2269	  Enable to turn on cpumask tests, running at boot or module load time.
2270
2271	  For more information on KUnit and unit tests in general, please refer
2272	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2273
2274	  If unsure, say N.
2275
2276config TEST_LIST_SORT
2277	tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2278	depends on KUNIT
2279	default KUNIT_ALL_TESTS
2280	help
2281	  Enable this to turn on 'list_sort()' function test. This test is
2282	  executed only once during system boot (so affects only boot time),
2283	  or at module load time.
2284
2285	  If unsure, say N.
2286
2287config TEST_MIN_HEAP
2288	tristate "Min heap test"
2289	depends on DEBUG_KERNEL || m
2290	help
2291	  Enable this to turn on min heap function tests. This test is
2292	  executed only once during system boot (so affects only boot time),
2293	  or at module load time.
2294
2295	  If unsure, say N.
2296
2297config TEST_SORT
2298	tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2299	depends on KUNIT
2300	default KUNIT_ALL_TESTS
2301	help
2302	  This option enables the self-test function of 'sort()' at boot,
2303	  or at module load time.
2304
2305	  If unsure, say N.
2306
2307config TEST_DIV64
2308	tristate "64bit/32bit division and modulo test"
2309	depends on DEBUG_KERNEL || m
2310	help
2311	  Enable this to turn on 'do_div()' function test. This test is
2312	  executed only once during system boot (so affects only boot time),
2313	  or at module load time.
2314
2315	  If unsure, say N.
2316
2317config TEST_MULDIV64
2318	tristate "mul_u64_u64_div_u64() test"
2319	depends on DEBUG_KERNEL || m
2320	help
2321	  Enable this to turn on 'mul_u64_u64_div_u64()' function test.
2322	  This test is executed only once during system boot (so affects
2323	  only boot time), or at module load time.
2324
2325	  If unsure, say N.
2326
2327config TEST_IOV_ITER
2328	tristate "Test iov_iter operation" if !KUNIT_ALL_TESTS
2329	depends on KUNIT
2330	depends on MMU
2331	default KUNIT_ALL_TESTS
2332	help
2333	  Enable this to turn on testing of the operation of the I/O iterator
2334	  (iov_iter). This test is executed only once during system boot (so
2335	  affects only boot time), or at module load time.
2336
2337	  If unsure, say N.
2338
2339config KPROBES_SANITY_TEST
2340	tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2341	depends on DEBUG_KERNEL
2342	depends on KPROBES
2343	depends on KUNIT
2344	select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2345	default KUNIT_ALL_TESTS
2346	help
2347	  This option provides for testing basic kprobes functionality on
2348	  boot. Samples of kprobe and kretprobe are inserted and
2349	  verified for functionality.
2350
2351	  Say N if you are unsure.
2352
2353config FPROBE_SANITY_TEST
2354	bool "Self test for fprobe"
2355	depends on DEBUG_KERNEL
2356	depends on FPROBE
2357	depends on KUNIT=y
2358	help
2359	  This option will enable testing the fprobe when the system boot.
2360	  A series of tests are made to verify that the fprobe is functioning
2361	  properly.
2362
2363	  Say N if you are unsure.
2364
2365config BACKTRACE_SELF_TEST
2366	tristate "Self test for the backtrace code"
2367	depends on DEBUG_KERNEL
2368	help
2369	  This option provides a kernel module that can be used to test
2370	  the kernel stack backtrace code. This option is not useful
2371	  for distributions or general kernels, but only for kernel
2372	  developers working on architecture code.
2373
2374	  Note that if you want to also test saved backtraces, you will
2375	  have to enable STACKTRACE as well.
2376
2377	  Say N if you are unsure.
2378
2379config TEST_REF_TRACKER
2380	tristate "Self test for reference tracker"
2381	depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2382	select REF_TRACKER
2383	help
2384	  This option provides a kernel module performing tests
2385	  using reference tracker infrastructure.
2386
2387	  Say N if you are unsure.
2388
2389config RBTREE_TEST
2390	tristate "Red-Black tree test"
2391	depends on DEBUG_KERNEL
2392	help
2393	  A benchmark measuring the performance of the rbtree library.
2394	  Also includes rbtree invariant checks.
2395
2396config REED_SOLOMON_TEST
2397	tristate "Reed-Solomon library test"
2398	depends on DEBUG_KERNEL || m
2399	select REED_SOLOMON
2400	select REED_SOLOMON_ENC16
2401	select REED_SOLOMON_DEC16
2402	help
2403	  This option enables the self-test function of rslib at boot,
2404	  or at module load time.
2405
2406	  If unsure, say N.
2407
2408config INTERVAL_TREE_TEST
2409	tristate "Interval tree test"
2410	depends on DEBUG_KERNEL
2411	select INTERVAL_TREE
2412	help
2413	  A benchmark measuring the performance of the interval tree library
2414
2415config PERCPU_TEST
2416	tristate "Per cpu operations test"
2417	depends on m && DEBUG_KERNEL
2418	help
2419	  Enable this option to build test module which validates per-cpu
2420	  operations.
2421
2422	  If unsure, say N.
2423
2424config ATOMIC64_SELFTEST
2425	tristate "Perform an atomic64_t self-test"
2426	help
2427	  Enable this option to test the atomic64_t functions at boot or
2428	  at module load time.
2429
2430	  If unsure, say N.
2431
2432config ASYNC_RAID6_TEST
2433	tristate "Self test for hardware accelerated raid6 recovery"
2434	depends on ASYNC_RAID6_RECOV
2435	select ASYNC_MEMCPY
2436	help
2437	  This is a one-shot self test that permutes through the
2438	  recovery of all the possible two disk failure scenarios for a
2439	  N-disk array.  Recovery is performed with the asynchronous
2440	  raid6 recovery routines, and will optionally use an offload
2441	  engine if one is available.
2442
2443	  If unsure, say N.
2444
2445config TEST_HEXDUMP
2446	tristate "Test functions located in the hexdump module at runtime"
2447
2448config PRINTF_KUNIT_TEST
2449	tristate "KUnit test printf() family of functions at runtime" if !KUNIT_ALL_TESTS
2450	depends on KUNIT
2451	default KUNIT_ALL_TESTS
2452	help
2453	  Enable this option to test the printf functions at runtime.
2454
2455	  If unsure, say N.
2456
2457config SCANF_KUNIT_TEST
2458	tristate "KUnit test scanf() family of functions at runtime" if !KUNIT_ALL_TESTS
2459	depends on KUNIT
2460	default KUNIT_ALL_TESTS
2461	help
2462	  Enable this option to test the scanf functions at runtime.
2463
2464	  If unsure, say N.
2465
2466config SEQ_BUF_KUNIT_TEST
2467	tristate "KUnit test for seq_buf" if !KUNIT_ALL_TESTS
2468	depends on KUNIT
2469	default KUNIT_ALL_TESTS
2470	help
2471	  This builds unit tests for the seq_buf library.
2472
2473	  If unsure, say N.
2474
2475config STRING_KUNIT_TEST
2476	tristate "KUnit test string functions at runtime" if !KUNIT_ALL_TESTS
2477	depends on KUNIT
2478	default KUNIT_ALL_TESTS
2479
2480config STRING_HELPERS_KUNIT_TEST
2481	tristate "KUnit test string helpers at runtime" if !KUNIT_ALL_TESTS
2482	depends on KUNIT
2483	default KUNIT_ALL_TESTS
2484
2485config FFS_KUNIT_TEST
2486	tristate "KUnit test ffs-family functions at runtime" if !KUNIT_ALL_TESTS
2487	depends on KUNIT
2488	default KUNIT_ALL_TESTS
2489	help
2490	  This builds KUnit tests for ffs-family bit manipulation functions
2491	  including ffs(), __ffs(), fls(), __fls(), fls64(), and __ffs64().
2492
2493	  These tests validate mathematical correctness, edge case handling,
2494	  and cross-architecture consistency of bit scanning functions.
2495
2496	  For more information on KUnit and unit tests in general,
2497	  please refer to Documentation/dev-tools/kunit/.
2498
2499config TEST_KSTRTOX
2500	tristate "Test kstrto*() family of functions at runtime"
2501
2502config TEST_BITMAP
2503	tristate "Test bitmap_*() family of functions at runtime"
2504	help
2505	  Enable this option to test the bitmap functions at boot.
2506
2507	  If unsure, say N.
2508
2509config TEST_UUID
2510	tristate "Test functions located in the uuid module at runtime"
2511
2512config TEST_XARRAY
2513	tristate "Test the XArray code at runtime"
2514
2515config TEST_MAPLE_TREE
2516	tristate "Test the Maple Tree code at runtime or module load"
2517	help
2518	  Enable this option to test the maple tree code functions at boot, or
2519	  when the module is loaded. Enable "Debug Maple Trees" will enable
2520	  more verbose output on failures.
2521
2522	  If unsure, say N.
2523
2524config TEST_RHASHTABLE
2525	tristate "Perform selftest on resizable hash table"
2526	help
2527	  Enable this option to test the rhashtable functions at boot.
2528
2529	  If unsure, say N.
2530
2531config TEST_IDA
2532	tristate "Perform selftest on IDA functions"
2533
2534config TEST_MISC_MINOR
2535	bool "miscdevice KUnit test" if !KUNIT_ALL_TESTS
2536	depends on KUNIT=y
2537	default KUNIT_ALL_TESTS
2538	help
2539	  Kunit test for miscdevice API, specially its behavior in respect to
2540	  static and dynamic minor numbers.
2541
2542	  KUnit tests run during boot and output the results to the debug log
2543	  in TAP format (https://testanything.org/). Only useful for kernel devs
2544	  running the KUnit test harness, and not intended for inclusion into a
2545	  production build.
2546
2547	  For more information on KUnit and unit tests in general please refer
2548	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2549
2550	  If unsure, say N.
2551
2552config TEST_PARMAN
2553	tristate "Perform selftest on priority array manager"
2554	depends on PARMAN
2555	help
2556	  Enable this option to test priority array manager on boot
2557	  (or module load).
2558
2559	  If unsure, say N.
2560
2561config TEST_IRQ_TIMINGS
2562	bool "IRQ timings selftest"
2563	depends on IRQ_TIMINGS
2564	help
2565	  Enable this option to test the irq timings code on boot.
2566
2567	  If unsure, say N.
2568
2569config TEST_LKM
2570	tristate "Test module loading with 'hello world' module"
2571	depends on m
2572	help
2573	  This builds the "test_module" module that emits "Hello, world"
2574	  on printk when loaded. It is designed to be used for basic
2575	  evaluation of the module loading subsystem (for example when
2576	  validating module verification). It lacks any extra dependencies,
2577	  and will not normally be loaded by the system unless explicitly
2578	  requested by name.
2579
2580	  If unsure, say N.
2581
2582config TEST_BITOPS
2583	tristate "Test module for compilation of bitops operations"
2584	help
2585	  This builds the "test_bitops" module that is much like the
2586	  TEST_LKM module except that it does a basic exercise of the
2587	  set/clear_bit macros and get_count_order/long to make sure there are
2588	  no compiler warnings from C=1 sparse checker or -Wextra
2589	  compilations. It has no dependencies and doesn't run or load unless
2590	  explicitly requested by name.  for example: modprobe test_bitops.
2591
2592	  If unsure, say N.
2593
2594config TEST_VMALLOC
2595	tristate "Test module for stress/performance analysis of vmalloc allocator"
2596	default n
2597	depends on MMU
2598	help
2599	  This builds the "test_vmalloc" module that should be used for
2600	  stress and performance analysis. So, any new change for vmalloc
2601	  subsystem can be evaluated from performance and stability point
2602	  of view.
2603
2604	  If unsure, say N.
2605
2606config TEST_BPF
2607	tristate "Test BPF filter functionality"
2608	depends on m && NET
2609	help
2610	  This builds the "test_bpf" module that runs various test vectors
2611	  against the BPF interpreter or BPF JIT compiler depending on the
2612	  current setting. This is in particular useful for BPF JIT compiler
2613	  development, but also to run regression tests against changes in
2614	  the interpreter code. It also enables test stubs for eBPF maps and
2615	  verifier used by user space verifier testsuite.
2616
2617	  If unsure, say N.
2618
2619config FIND_BIT_BENCHMARK
2620	tristate "Test find_bit functions"
2621	help
2622	  This builds the "test_find_bit" module that measure find_*_bit()
2623	  functions performance.
2624
2625	  If unsure, say N.
2626
2627config FIND_BIT_BENCHMARK_RUST
2628	tristate "Test find_bit functions in Rust"
2629	depends on RUST
2630	help
2631	  This builds the "find_bit_benchmark_rust" module. It is a micro
2632          benchmark that measures the performance of Rust functions that
2633          correspond to the find_*_bit() operations in C. It follows the
2634          FIND_BIT_BENCHMARK closely but will in general not yield same
2635          numbers due to extra bounds checks and overhead of foreign
2636          function calls.
2637
2638	  If unsure, say N.
2639
2640config TEST_FIRMWARE
2641	tristate "Test firmware loading via userspace interface"
2642	depends on FW_LOADER
2643	help
2644	  This builds the "test_firmware" module that creates a userspace
2645	  interface for testing firmware loading. This can be used to
2646	  control the triggering of firmware loading without needing an
2647	  actual firmware-using device. The contents can be rechecked by
2648	  userspace.
2649
2650	  If unsure, say N.
2651
2652config TEST_SYSCTL
2653	tristate "sysctl test driver"
2654	depends on PROC_SYSCTL
2655	help
2656	  This builds the "test_sysctl" module. This driver enables to test the
2657	  proc sysctl interfaces available to drivers safely without affecting
2658	  production knobs which might alter system functionality.
2659
2660	  If unsure, say N.
2661
2662config BITFIELD_KUNIT
2663	tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2664	depends on KUNIT
2665	default KUNIT_ALL_TESTS
2666	help
2667	  Enable this option to test the bitfield functions at boot.
2668
2669	  KUnit tests run during boot and output the results to the debug log
2670	  in TAP format (http://testanything.org/). Only useful for kernel devs
2671	  running the KUnit test harness, and not intended for inclusion into a
2672	  production build.
2673
2674	  For more information on KUnit and unit tests in general please refer
2675	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2676
2677	  If unsure, say N.
2678
2679config CHECKSUM_KUNIT
2680	tristate "KUnit test checksum functions at runtime" if !KUNIT_ALL_TESTS
2681	depends on KUNIT
2682	default KUNIT_ALL_TESTS
2683	help
2684	  Enable this option to test the checksum functions at boot.
2685
2686	  KUnit tests run during boot and output the results to the debug log
2687	  in TAP format (http://testanything.org/). Only useful for kernel devs
2688	  running the KUnit test harness, and not intended for inclusion into a
2689	  production build.
2690
2691	  For more information on KUnit and unit tests in general please refer
2692	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2693
2694	  If unsure, say N.
2695
2696config UTIL_MACROS_KUNIT
2697	tristate "KUnit test util_macros.h functions at runtime" if !KUNIT_ALL_TESTS
2698	depends on KUNIT
2699	default KUNIT_ALL_TESTS
2700	help
2701	  Enable this option to test the util_macros.h function at boot.
2702
2703	  KUnit tests run during boot and output the results to the debug log
2704	  in TAP format (http://testanything.org/). Only useful for kernel devs
2705	  running the KUnit test harness, and not intended for inclusion into a
2706	  production build.
2707
2708	  For more information on KUnit and unit tests in general please refer
2709	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2710
2711	  If unsure, say N.
2712
2713config HASH_KUNIT_TEST
2714	tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2715	depends on KUNIT
2716	default KUNIT_ALL_TESTS
2717	help
2718	  Enable this option to test the kernel's string (<linux/stringhash.h>), and
2719	  integer (<linux/hash.h>) hash functions on boot.
2720
2721	  KUnit tests run during boot and output the results to the debug log
2722	  in TAP format (https://testanything.org/). Only useful for kernel devs
2723	  running the KUnit test harness, and not intended for inclusion into a
2724	  production build.
2725
2726	  For more information on KUnit and unit tests in general please refer
2727	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2728
2729	  This is intended to help people writing architecture-specific
2730	  optimized versions. If unsure, say N.
2731
2732config RESOURCE_KUNIT_TEST
2733	tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2734	depends on KUNIT
2735	default KUNIT_ALL_TESTS
2736	select GET_FREE_REGION
2737	help
2738	  This builds the resource API unit test.
2739	  Tests the logic of API provided by resource.c and ioport.h.
2740	  For more information on KUnit and unit tests in general please refer
2741	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2742
2743	  If unsure, say N.
2744
2745config SYSCTL_KUNIT_TEST
2746	tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2747	depends on KUNIT
2748	default KUNIT_ALL_TESTS
2749	help
2750	  This builds the proc sysctl unit test, which runs on boot.
2751	  Tests the API contract and implementation correctness of sysctl.
2752	  For more information on KUnit and unit tests in general please refer
2753	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2754
2755	  If unsure, say N.
2756
2757config KFIFO_KUNIT_TEST
2758	tristate "KUnit Test for the generic kernel FIFO implementation" if !KUNIT_ALL_TESTS
2759	depends on KUNIT
2760	default KUNIT_ALL_TESTS
2761	help
2762	  This builds the generic FIFO implementation KUnit test suite.
2763	  It tests that the API and basic functionality of the kfifo type
2764	  and associated macros.
2765
2766	  For more information on KUnit and unit tests in general please refer
2767	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2768
2769	  If unsure, say N.
2770
2771config LIST_KUNIT_TEST
2772	tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2773	depends on KUNIT
2774	default KUNIT_ALL_TESTS
2775	help
2776	  This builds the linked list KUnit test suite.
2777	  It tests that the API and basic functionality of the list_head type
2778	  and associated macros.
2779
2780	  KUnit tests run during boot and output the results to the debug log
2781	  in TAP format (https://testanything.org/). Only useful for kernel devs
2782	  running the KUnit test harness, and not intended for inclusion into a
2783	  production build.
2784
2785	  For more information on KUnit and unit tests in general please refer
2786	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2787
2788	  If unsure, say N.
2789
2790config HASHTABLE_KUNIT_TEST
2791	tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS
2792	depends on KUNIT
2793	default KUNIT_ALL_TESTS
2794	help
2795	  This builds the hashtable KUnit test suite.
2796	  It tests the basic functionality of the API defined in
2797	  include/linux/hashtable.h. For more information on KUnit and
2798	  unit tests in general please refer to the KUnit documentation
2799	  in Documentation/dev-tools/kunit/.
2800
2801	  If unsure, say N.
2802
2803config LINEAR_RANGES_TEST
2804	tristate "KUnit test for linear_ranges"
2805	depends on KUNIT
2806	select LINEAR_RANGES
2807	help
2808	  This builds the linear_ranges unit test, which runs on boot.
2809	  Tests the linear_ranges logic correctness.
2810	  For more information on KUnit and unit tests in general please refer
2811	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2812
2813	  If unsure, say N.
2814
2815config CMDLINE_KUNIT_TEST
2816	tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2817	depends on KUNIT
2818	default KUNIT_ALL_TESTS
2819	help
2820	  This builds the cmdline API unit test.
2821	  Tests the logic of API provided by cmdline.c.
2822	  For more information on KUnit and unit tests in general please refer
2823	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2824
2825	  If unsure, say N.
2826
2827config BITS_TEST
2828	tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2829	depends on KUNIT
2830	default KUNIT_ALL_TESTS
2831	help
2832	  This builds the bits unit test.
2833	  Tests the logic of macros defined in bits.h.
2834	  For more information on KUnit and unit tests in general please refer
2835	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2836
2837	  If unsure, say N.
2838
2839config SLUB_KUNIT_TEST
2840	tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2841	depends on SLUB_DEBUG && KUNIT
2842	default KUNIT_ALL_TESTS
2843	help
2844	  This builds SLUB allocator unit test.
2845	  Tests SLUB cache debugging functionality.
2846	  For more information on KUnit and unit tests in general please refer
2847	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2848
2849	  If unsure, say N.
2850
2851config RATIONAL_KUNIT_TEST
2852	tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2853	depends on KUNIT && RATIONAL
2854	default KUNIT_ALL_TESTS
2855	help
2856	  This builds the rational math unit test.
2857	  For more information on KUnit and unit tests in general please refer
2858	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2859
2860	  If unsure, say N.
2861
2862config MEMCPY_KUNIT_TEST
2863	tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2864	depends on KUNIT
2865	default KUNIT_ALL_TESTS
2866	help
2867	  Builds unit tests for memcpy(), memmove(), and memset() functions.
2868	  For more information on KUnit and unit tests in general please refer
2869	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2870
2871	  If unsure, say N.
2872
2873config IS_SIGNED_TYPE_KUNIT_TEST
2874	tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2875	depends on KUNIT
2876	default KUNIT_ALL_TESTS
2877	help
2878	  Builds unit tests for the is_signed_type() macro.
2879
2880	  For more information on KUnit and unit tests in general please refer
2881	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2882
2883	  If unsure, say N.
2884
2885config OVERFLOW_KUNIT_TEST
2886	tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2887	depends on KUNIT
2888	default KUNIT_ALL_TESTS
2889	help
2890	  Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2891	  related functions.
2892
2893	  For more information on KUnit and unit tests in general please refer
2894	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2895
2896	  If unsure, say N.
2897
2898config RANDSTRUCT_KUNIT_TEST
2899	tristate "Test randstruct structure layout randomization at runtime" if !KUNIT_ALL_TESTS
2900	depends on KUNIT
2901	default KUNIT_ALL_TESTS
2902	help
2903	  Builds unit tests for the checking CONFIG_RANDSTRUCT=y, which
2904	  randomizes structure layouts.
2905
2906config STACKINIT_KUNIT_TEST
2907	tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2908	depends on KUNIT
2909	default KUNIT_ALL_TESTS
2910	help
2911	  Test if the kernel is zero-initializing stack variables and
2912	  padding. Coverage is controlled by compiler flags,
2913	  CONFIG_INIT_STACK_ALL_PATTERN or CONFIG_INIT_STACK_ALL_ZERO.
2914
2915config FORTIFY_KUNIT_TEST
2916	tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2917	depends on KUNIT
2918	default KUNIT_ALL_TESTS
2919	help
2920	  Builds unit tests for checking internals of FORTIFY_SOURCE as used
2921	  by the str*() and mem*() family of functions. For testing runtime
2922	  traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2923
2924config LONGEST_SYM_KUNIT_TEST
2925	tristate "Test the longest symbol possible" if !KUNIT_ALL_TESTS
2926	depends on KUNIT && KPROBES
2927	depends on !PREFIX_SYMBOLS && !CFI && !GCOV_KERNEL
2928	default KUNIT_ALL_TESTS
2929	help
2930	  Tests the longest symbol possible
2931
2932	  If unsure, say N.
2933
2934config HW_BREAKPOINT_KUNIT_TEST
2935	bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2936	depends on HAVE_HW_BREAKPOINT
2937	depends on KUNIT=y
2938	default KUNIT_ALL_TESTS
2939	help
2940	  Tests for hw_breakpoint constraints accounting.
2941
2942	  If unsure, say N.
2943
2944config SIPHASH_KUNIT_TEST
2945	tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2946	depends on KUNIT
2947	default KUNIT_ALL_TESTS
2948	help
2949	  Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2950	  functions on boot (or module load).
2951
2952	  This is intended to help people writing architecture-specific
2953	  optimized versions.  If unsure, say N.
2954
2955config USERCOPY_KUNIT_TEST
2956	tristate "KUnit Test for user/kernel boundary protections"
2957	depends on KUNIT
2958	default KUNIT_ALL_TESTS
2959	help
2960	  This builds the "usercopy_kunit" module that runs sanity checks
2961	  on the copy_to/from_user infrastructure, making sure basic
2962	  user/kernel boundary testing is working.
2963
2964config BLACKHOLE_DEV_KUNIT_TEST
2965	tristate "Test blackhole netdev functionality" if !KUNIT_ALL_TESTS
2966	depends on NET
2967	depends on KUNIT
2968	default KUNIT_ALL_TESTS
2969	help
2970	  This builds the "blackhole_dev_kunit" module that validates the
2971	  data path through this blackhole netdev.
2972
2973	  If unsure, say N.
2974
2975config TEST_UDELAY
2976	tristate "udelay test driver"
2977	help
2978	  This builds the "udelay_test" module that helps to make sure
2979	  that udelay() is working properly.
2980
2981	  If unsure, say N.
2982
2983config TEST_STATIC_KEYS
2984	tristate "Test static keys"
2985	depends on m
2986	help
2987	  Test the static key interfaces.
2988
2989	  If unsure, say N.
2990
2991config TEST_DYNAMIC_DEBUG
2992	tristate "Test DYNAMIC_DEBUG"
2993	depends on DYNAMIC_DEBUG
2994	help
2995	  This module registers a tracer callback to count enabled
2996	  pr_debugs in a 'do_debugging' function, then alters their
2997	  enablements, calls the function, and compares counts.
2998
2999	  If unsure, say N.
3000
3001config TEST_KMOD
3002	tristate "kmod stress tester"
3003	depends on m
3004	select TEST_LKM
3005	help
3006	  Test the kernel's module loading mechanism: kmod. kmod implements
3007	  support to load modules using the Linux kernel's usermode helper.
3008	  This test provides a series of tests against kmod.
3009
3010	  Although technically you can either build test_kmod as a module or
3011	  into the kernel we disallow building it into the kernel since
3012	  it stress tests request_module() and this will very likely cause
3013	  some issues by taking over precious threads available from other
3014	  module load requests, ultimately this could be fatal.
3015
3016	  To run tests run:
3017
3018	  tools/testing/selftests/kmod/kmod.sh --help
3019
3020	  If unsure, say N.
3021
3022config TEST_RUNTIME
3023	bool
3024
3025config TEST_RUNTIME_MODULE
3026	bool
3027
3028config TEST_KALLSYMS
3029	tristate "module kallsyms find_symbol() test"
3030	depends on m
3031	select TEST_RUNTIME
3032	select TEST_RUNTIME_MODULE
3033	select TEST_KALLSYMS_A
3034	select TEST_KALLSYMS_B
3035	select TEST_KALLSYMS_C
3036	select TEST_KALLSYMS_D
3037	help
3038	  This allows us to stress test find_symbol() through the kallsyms
3039	  used to place symbols on the kernel ELF kallsyms and modules kallsyms
3040	  where we place kernel symbols such as exported symbols.
3041
3042	  We have four test modules:
3043
3044	  A: has KALLSYSMS_NUMSYMS exported symbols
3045	  B: uses one of A's symbols
3046	  C: adds KALLSYMS_SCALE_FACTOR * KALLSYSMS_NUMSYMS exported
3047	  D: adds 2 * the symbols than C
3048
3049	  We stress test find_symbol() through two means:
3050
3051	  1) Upon load of B it will trigger simplify_symbols() to look for the
3052	  one symbol it uses from the module A with tons of symbols. This is an
3053	  indirect way for us to have B call resolve_symbol_wait() upon module
3054	  load. This will eventually call find_symbol() which will eventually
3055	  try to find the symbols used with find_exported_symbol_in_section().
3056	  find_exported_symbol_in_section() uses bsearch() so a binary search
3057	  for each symbol. Binary search will at worst be O(log(n)) so the
3058	  larger TEST_MODULE_KALLSYSMS the worse the search.
3059
3060	  2) The selftests should load C first, before B. Upon B's load towards
3061	  the end right before we call module B's init routine we get
3062	  complete_formation() called on the module. That will first check
3063	  for duplicate symbols with the call to verify_exported_symbols().
3064	  That is when we'll force iteration on module C's insane symbol list.
3065	  Since it has 10 * KALLSYMS_NUMSYMS it means we can first test
3066	  just loading B without C. The amount of time it takes to load C Vs
3067	  B can give us an idea of the impact growth of the symbol space and
3068	  give us projection. Module A only uses one symbol from B so to allow
3069	  this scaling in module C to be proportional, if it used more symbols
3070	  then the first test would be doing more and increasing just the
3071	  search space would be slightly different. The last module, module D
3072	  will just increase the search space by twice the number of symbols in
3073	  C so to allow for full projects.
3074
3075	  tools/testing/selftests/module/find_symbol.sh
3076
3077	  The current defaults will incur a build delay of about 7 minutes
3078	  on an x86_64 with only 8 cores. Enable this only if you want to
3079	  stress test find_symbol() with thousands of symbols. At the same
3080	  time this is also useful to test building modules with thousands of
3081	  symbols, and if BTF is enabled this also stress tests adding BTF
3082	  information for each module. Currently enabling many more symbols
3083	  will segfault the build system.
3084
3085	  If unsure, say N.
3086
3087if TEST_KALLSYMS
3088
3089config TEST_KALLSYMS_A
3090	tristate
3091	depends on m
3092
3093config TEST_KALLSYMS_B
3094	tristate
3095	depends on m
3096
3097config TEST_KALLSYMS_C
3098	tristate
3099	depends on m
3100
3101config TEST_KALLSYMS_D
3102	tristate
3103	depends on m
3104
3105choice
3106	prompt "Kallsym test range"
3107	default TEST_KALLSYMS_LARGE
3108	help
3109	  Selecting something other than "Fast" will enable tests which slow
3110	  down the build and may crash your build.
3111
3112config TEST_KALLSYMS_FAST
3113	bool "Fast builds"
3114	help
3115	  You won't really be testing kallsysms, so this just helps fast builds
3116	  when allmodconfig is used..
3117
3118config TEST_KALLSYMS_LARGE
3119	bool "Enable testing kallsyms with large exports"
3120	help
3121	  This will enable larger number of symbols. This will slow down
3122	  your build considerably.
3123
3124config TEST_KALLSYMS_MAX
3125	bool "Known kallsysms limits"
3126	help
3127	  This will enable exports to the point we know we'll start crashing
3128	  builds.
3129
3130endchoice
3131
3132config TEST_KALLSYMS_NUMSYMS
3133	int "test kallsyms number of symbols"
3134	range 2 10000
3135	default 2 if TEST_KALLSYMS_FAST
3136	default 100 if TEST_KALLSYMS_LARGE
3137	default 10000 if TEST_KALLSYMS_MAX
3138	help
3139	  The number of symbols to create on TEST_KALLSYMS_A, only one of which
3140	  module TEST_KALLSYMS_B will use. This also will be used
3141	  for how many symbols TEST_KALLSYMS_C will have, scaled up by
3142	  TEST_KALLSYMS_SCALE_FACTOR. Note that setting this to 10,000 will
3143	  trigger a segfault today, don't use anything close to it unless
3144	  you are aware that this should not be used for automated build tests.
3145
3146config TEST_KALLSYMS_SCALE_FACTOR
3147	int "test kallsyms scale factor"
3148	default 8
3149	help
3150	  How many more unusued symbols will TEST_KALLSYSMS_C have than
3151	  TEST_KALLSYMS_A. If 8, then module C will have 8 * syms
3152	  than module A. Then TEST_KALLSYMS_D will have double the amount
3153	  of symbols than C so to allow projections.
3154
3155endif # TEST_KALLSYMS
3156
3157config TEST_DEBUG_VIRTUAL
3158	tristate "Test CONFIG_DEBUG_VIRTUAL feature"
3159	depends on DEBUG_VIRTUAL
3160	help
3161	  Test the kernel's ability to detect incorrect calls to
3162	  virt_to_phys() done against the non-linear part of the
3163	  kernel's virtual address map.
3164
3165	  If unsure, say N.
3166
3167config TEST_MEMCAT_P
3168	tristate "Test memcat_p() helper function"
3169	help
3170	  Test the memcat_p() helper for correctly merging two
3171	  pointer arrays together.
3172
3173	  If unsure, say N.
3174
3175config TEST_OBJAGG
3176	tristate "Perform selftest on object aggreration manager"
3177	default n
3178	depends on OBJAGG
3179	help
3180	  Enable this option to test object aggregation manager on boot
3181	  (or module load).
3182
3183config TEST_MEMINIT
3184	tristate "Test heap/page initialization"
3185	help
3186	  Test if the kernel is zero-initializing heap and page allocations.
3187	  This can be useful to test init_on_alloc and init_on_free features.
3188
3189	  If unsure, say N.
3190
3191config TEST_HMM
3192	tristate "Test HMM (Heterogeneous Memory Management)"
3193	depends on TRANSPARENT_HUGEPAGE
3194	depends on DEVICE_PRIVATE
3195	select HMM_MIRROR
3196	select MMU_NOTIFIER
3197	help
3198	  This is a pseudo device driver solely for testing HMM.
3199	  Say M here if you want to build the HMM test module.
3200	  Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
3201
3202	  If unsure, say N.
3203
3204config TEST_FREE_PAGES
3205	tristate "Test freeing pages"
3206	help
3207	  Test that a memory leak does not occur due to a race between
3208	  freeing a block of pages and a speculative page reference.
3209	  Loading this module is safe if your kernel has the bug fixed.
3210	  If the bug is not fixed, it will leak gigabytes of memory and
3211	  probably OOM your system.
3212
3213config TEST_FPU
3214	tristate "Test floating point operations in kernel space"
3215	depends on ARCH_HAS_KERNEL_FPU_SUPPORT && !KCOV_INSTRUMENT_ALL
3216	help
3217	  Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
3218	  which will trigger a sequence of floating point operations. This is used
3219	  for self-testing floating point control register setting in
3220	  kernel_fpu_begin().
3221
3222	  If unsure, say N.
3223
3224config TEST_CLOCKSOURCE_WATCHDOG
3225	tristate "Test clocksource watchdog in kernel space"
3226	depends on CLOCKSOURCE_WATCHDOG
3227	help
3228	  Enable this option to create a kernel module that will trigger
3229	  a test of the clocksource watchdog.  This module may be loaded
3230	  via modprobe or insmod in which case it will run upon being
3231	  loaded, or it may be built in, in which case it will run
3232	  shortly after boot.
3233
3234	  If unsure, say N.
3235
3236config TEST_OBJPOOL
3237	tristate "Test module for correctness and stress of objpool"
3238	default n
3239	depends on m && DEBUG_KERNEL
3240	help
3241	  This builds the "test_objpool" module that should be used for
3242	  correctness verification and concurrent testings of objects
3243	  allocation and reclamation.
3244
3245	  If unsure, say N.
3246
3247config TEST_KEXEC_HANDOVER
3248	bool "Test for Kexec HandOver"
3249	default n
3250	depends on KEXEC_HANDOVER
3251	help
3252	  This option enables test for Kexec HandOver (KHO).
3253	  The test consists of two parts: saving kernel data before kexec and
3254	  restoring the data after kexec and verifying that it was properly
3255	  handed over. This test module creates and saves data on the boot of
3256	  the first kernel and restores and verifies the data on the boot of
3257	  kexec'ed kernel.
3258
3259	  For detailed documentation about KHO, see Documentation/core-api/kho.
3260
3261	  To run the test run:
3262
3263	  tools/testing/selftests/kho/vmtest.sh -h
3264
3265	  If unsure, say N.
3266
3267config RATELIMIT_KUNIT_TEST
3268	tristate "KUnit Test for correctness and stress of ratelimit" if !KUNIT_ALL_TESTS
3269	depends on KUNIT
3270	default KUNIT_ALL_TESTS
3271	help
3272	  This builds the "test_ratelimit" module that should be used
3273	  for correctness verification and concurrent testings of rate
3274	  limiting.
3275
3276	  If unsure, say N.
3277
3278config INT_POW_KUNIT_TEST
3279	tristate "Integer exponentiation (int_pow) test" if !KUNIT_ALL_TESTS
3280	depends on KUNIT
3281	default KUNIT_ALL_TESTS
3282	help
3283	  This option enables the KUnit test suite for the int_pow function,
3284	  which performs integer exponentiation. The test suite is designed to
3285	  verify that the implementation of int_pow correctly computes the power
3286	  of a given base raised to a given exponent.
3287
3288	  Enabling this option will include tests that check various scenarios
3289	  and edge cases to ensure the accuracy and reliability of the exponentiation
3290	  function.
3291
3292	  If unsure, say N
3293
3294config INT_SQRT_KUNIT_TEST
3295	tristate "Integer square root test" if !KUNIT_ALL_TESTS
3296	depends on KUNIT
3297	default KUNIT_ALL_TESTS
3298	help
3299	  This option enables the KUnit test suite for the int_sqrt() function,
3300	  which performs square root calculation. The test suite checks
3301	  various scenarios, including edge cases, to ensure correctness.
3302
3303	  Enabling this option will include tests that check various scenarios
3304	  and edge cases to ensure the accuracy and reliability of the square root
3305	  function.
3306
3307	  If unsure, say N
3308
3309config INT_LOG_KUNIT_TEST
3310        tristate "Integer log (int_log) test" if !KUNIT_ALL_TESTS
3311        depends on KUNIT
3312        default KUNIT_ALL_TESTS
3313        help
3314          This option enables the KUnit test suite for the int_log library, which
3315          provides two functions to compute the integer logarithm in base 2 and
3316          base 10, called respectively as intlog2 and intlog10.
3317
3318          If unsure, say N
3319
3320config GCD_KUNIT_TEST
3321	tristate "Greatest common divisor test" if !KUNIT_ALL_TESTS
3322	depends on KUNIT
3323	default KUNIT_ALL_TESTS
3324	help
3325	  This option enables the KUnit test suite for the gcd() function,
3326	  which computes the greatest common divisor of two numbers.
3327
3328	  This test suite verifies the correctness of gcd() across various
3329	  scenarios, including edge cases.
3330
3331	  If unsure, say N
3332
3333config PRIME_NUMBERS_KUNIT_TEST
3334	tristate "Prime number generator test" if !KUNIT_ALL_TESTS
3335	depends on KUNIT
3336	depends on PRIME_NUMBERS
3337	default KUNIT_ALL_TESTS
3338	help
3339	  This option enables the KUnit test suite for the {is,next}_prime_number
3340	  functions.
3341
3342	  Enabling this option will include tests that compare the prime number
3343	  generator functions against a brute force implementation.
3344
3345	  If unsure, say N
3346
3347endif # RUNTIME_TESTING_MENU
3348
3349config ARCH_USE_MEMTEST
3350	bool
3351	help
3352	  An architecture should select this when it uses early_memtest()
3353	  during boot process.
3354
3355config MEMTEST
3356	bool "Memtest"
3357	depends on ARCH_USE_MEMTEST
3358	help
3359	  This option adds a kernel parameter 'memtest', which allows memtest
3360	  to be set and executed.
3361	        memtest=0, mean disabled; -- default
3362	        memtest=1, mean do 1 test pattern;
3363	        ...
3364	        memtest=17, mean do 17 test patterns.
3365	  If you are unsure how to answer this question, answer N.
3366
3367
3368
3369config HYPERV_TESTING
3370	bool "Microsoft Hyper-V driver testing"
3371	default n
3372	depends on HYPERV && DEBUG_FS
3373	help
3374	  Select this option to enable Hyper-V vmbus testing.
3375
3376endmenu # "Kernel Testing and Coverage"
3377
3378menu "Rust hacking"
3379
3380config RUST_DEBUG_ASSERTIONS
3381	bool "Debug assertions"
3382	depends on RUST
3383	help
3384	  Enables rustc's `-Cdebug-assertions` codegen option.
3385
3386	  This flag lets you turn `cfg(debug_assertions)` conditional
3387	  compilation on or off. This can be used to enable extra debugging
3388	  code in development but not in production. For example, it controls
3389	  the behavior of the standard library's `debug_assert!` macro.
3390
3391	  Note that this will apply to all Rust code, including `core`.
3392
3393	  If unsure, say N.
3394
3395config RUST_OVERFLOW_CHECKS
3396	bool "Overflow checks"
3397	default y
3398	depends on RUST
3399	help
3400	  Enables rustc's `-Coverflow-checks` codegen option.
3401
3402	  This flag allows you to control the behavior of runtime integer
3403	  overflow. When overflow-checks are enabled, a Rust panic will occur
3404	  on overflow.
3405
3406	  Note that this will apply to all Rust code, including `core`.
3407
3408	  If unsure, say Y.
3409
3410config RUST_BUILD_ASSERT_ALLOW
3411	bool "Allow unoptimized build-time assertions"
3412	depends on RUST
3413	help
3414	  Controls how `build_error!` and `build_assert!` are handled during the build.
3415
3416	  If calls to them exist in the binary, it may indicate a violated invariant
3417	  or that the optimizer failed to verify the invariant during compilation.
3418
3419	  This should not happen, thus by default the build is aborted. However,
3420	  as an escape hatch, you can choose Y here to ignore them during build
3421	  and let the check be carried at runtime (with `panic!` being called if
3422	  the check fails).
3423
3424	  If unsure, say N.
3425
3426config RUST_KERNEL_DOCTESTS
3427	bool "Doctests for the `kernel` crate" if !KUNIT_ALL_TESTS
3428	depends on RUST && KUNIT=y
3429	default KUNIT_ALL_TESTS
3430	help
3431	  This builds the documentation tests of the `kernel` crate
3432	  as KUnit tests.
3433
3434	  For more information on KUnit and unit tests in general,
3435	  please refer to the KUnit documentation in Documentation/dev-tools/kunit/.
3436
3437	  If unsure, say N.
3438
3439endmenu # "Rust"
3440
3441endmenu # Kernel hacking
3442