xref: /linux-6.15/lib/Kconfig.debug (revision 2cd5769f)
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
209endmenu # "printk and dmesg options"
210
211config DEBUG_KERNEL
212	bool "Kernel debugging"
213	help
214	  Say Y here if you are developing drivers or trying to debug and
215	  identify kernel problems.
216
217config DEBUG_MISC
218	bool "Miscellaneous debug code"
219	default DEBUG_KERNEL
220	depends on DEBUG_KERNEL
221	help
222	  Say Y here if you need to enable miscellaneous debug code that should
223	  be under a more specific debug option but isn't.
224
225menu "Compile-time checks and compiler options"
226
227config DEBUG_INFO
228	bool
229	help
230	  A kernel debug info option other than "None" has been selected
231	  in the "Debug information" choice below, indicating that debug
232	  information will be generated for build targets.
233
234# Clang generates .uleb128 with label differences for DWARF v5, a feature that
235# older binutils ports do not support when utilizing RISC-V style linker
236# relaxation: https://sourceware.org/bugzilla/show_bug.cgi?id=27215
237config AS_HAS_NON_CONST_ULEB128
238	def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:)
239
240choice
241	prompt "Debug information"
242	depends on DEBUG_KERNEL
243	help
244	  Selecting something other than "None" results in a kernel image
245	  that will include debugging info resulting in a larger kernel image.
246	  This adds debug symbols to the kernel and modules (gcc -g), and
247	  is needed if you intend to use kernel crashdump or binary object
248	  tools like crash, kgdb, LKCD, gdb, etc on the kernel.
249
250	  Choose which version of DWARF debug info to emit. If unsure,
251	  select "Toolchain default".
252
253config DEBUG_INFO_NONE
254	bool "Disable debug information"
255	help
256	  Do not build the kernel with debugging information, which will
257	  result in a faster and smaller build.
258
259config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
260	bool "Rely on the toolchain's implicit default DWARF version"
261	select DEBUG_INFO
262	depends on !CC_IS_CLANG || AS_IS_LLVM || CLANG_VERSION < 140000 || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128)
263	help
264	  The implicit default version of DWARF debug info produced by a
265	  toolchain changes over time.
266
267	  This can break consumers of the debug info that haven't upgraded to
268	  support newer revisions, and prevent testing newer versions, but
269	  those should be less common scenarios.
270
271config DEBUG_INFO_DWARF4
272	bool "Generate DWARF Version 4 debuginfo"
273	select DEBUG_INFO
274	depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)
275	help
276	  Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2
277	  if using clang without clang's integrated assembler, and gdb 7.0+.
278
279	  If you have consumers of DWARF debug info that are not ready for
280	  newer revisions of DWARF, you may wish to choose this or have your
281	  config select this.
282
283config DEBUG_INFO_DWARF5
284	bool "Generate DWARF Version 5 debuginfo"
285	select DEBUG_INFO
286	depends on !ARCH_HAS_BROKEN_DWARF5
287	depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128)
288	help
289	  Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
290	  5.0+ accepts the -gdwarf-5 flag but only had partial support for some
291	  draft features until 7.0), and gdb 8.0+.
292
293	  Changes to the structure of debug info in Version 5 allow for around
294	  15-18% savings in resulting image and debug info section sizes as
295	  compared to DWARF Version 4. DWARF Version 5 standardizes previous
296	  extensions such as accelerators for symbol indexing and the format
297	  for fission (.dwo/.dwp) files. Users may not want to select this
298	  config if they rely on tooling that has not yet been updated to
299	  support DWARF Version 5.
300
301endchoice # "Debug information"
302
303if DEBUG_INFO
304
305config DEBUG_INFO_REDUCED
306	bool "Reduce debugging information"
307	help
308	  If you say Y here gcc is instructed to generate less debugging
309	  information for structure types. This means that tools that
310	  need full debugging information (like kgdb or systemtap) won't
311	  be happy. But if you merely need debugging information to
312	  resolve line numbers there is no loss. Advantage is that
313	  build directory object sizes shrink dramatically over a full
314	  DEBUG_INFO build and compile times are reduced too.
315	  Only works with newer gcc versions.
316
317choice
318	prompt "Compressed Debug information"
319	help
320	  Compress the resulting debug info. Results in smaller debug info sections,
321	  but requires that consumers are able to decompress the results.
322
323	  If unsure, choose DEBUG_INFO_COMPRESSED_NONE.
324
325config DEBUG_INFO_COMPRESSED_NONE
326	bool "Don't compress debug information"
327	help
328	  Don't compress debug info sections.
329
330config DEBUG_INFO_COMPRESSED_ZLIB
331	bool "Compress debugging information with zlib"
332	depends on $(cc-option,-gz=zlib)
333	depends on $(ld-option,--compress-debug-sections=zlib)
334	help
335	  Compress the debug information using zlib.  Requires GCC 5.0+ or Clang
336	  5.0+, binutils 2.26+, and zlib.
337
338	  Users of dpkg-deb via scripts/package/builddeb may find an increase in
339	  size of their debug .deb packages with this config set, due to the
340	  debug info being compressed with zlib, then the object files being
341	  recompressed with a different compression scheme. But this is still
342	  preferable to setting $KDEB_COMPRESS to "none" which would be even
343	  larger.
344
345config DEBUG_INFO_COMPRESSED_ZSTD
346	bool "Compress debugging information with zstd"
347	depends on $(cc-option,-gz=zstd)
348	depends on $(ld-option,--compress-debug-sections=zstd)
349	help
350	  Compress the debug information using zstd.  This may provide better
351	  compression than zlib, for about the same time costs, but requires newer
352	  toolchain support.  Requires GCC 13.0+ or Clang 16.0+, binutils 2.40+, and
353	  zstd.
354
355endchoice # "Compressed Debug information"
356
357config DEBUG_INFO_SPLIT
358	bool "Produce split debuginfo in .dwo files"
359	depends on $(cc-option,-gsplit-dwarf)
360	# RISC-V linker relaxation + -gsplit-dwarf has issues with LLVM and GCC
361	# prior to 12.x:
362	# https://github.com/llvm/llvm-project/issues/56642
363	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99090
364	depends on !RISCV || GCC_VERSION >= 120000
365	help
366	  Generate debug info into separate .dwo files. This significantly
367	  reduces the build directory size for builds with DEBUG_INFO,
368	  because it stores the information only once on disk in .dwo
369	  files instead of multiple times in object files and executables.
370	  In addition the debug information is also compressed.
371
372	  Requires recent gcc (4.7+) and recent gdb/binutils.
373	  Any tool that packages or reads debug information would need
374	  to know about the .dwo files and include them.
375	  Incompatible with older versions of ccache.
376
377config DEBUG_INFO_BTF
378	bool "Generate BTF type information"
379	depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
380	depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
381	depends on BPF_SYSCALL
382	depends on PAHOLE_VERSION >= 116
383	depends on DEBUG_INFO_DWARF4 || PAHOLE_VERSION >= 121
384	# pahole uses elfutils, which does not have support for Hexagon relocations
385	depends on !HEXAGON
386	help
387	  Generate deduplicated BTF type information from DWARF debug info.
388	  Turning this on requires pahole v1.16 or later (v1.21 or later to
389	  support DWARF 5), which will convert DWARF type info into equivalent
390	  deduplicated BTF type info.
391
392config PAHOLE_HAS_SPLIT_BTF
393	def_bool PAHOLE_VERSION >= 119
394
395config PAHOLE_HAS_BTF_TAG
396	def_bool PAHOLE_VERSION >= 123
397	depends on CC_IS_CLANG
398	help
399	  Decide whether pahole emits btf_tag attributes (btf_type_tag and
400	  btf_decl_tag) or not. Currently only clang compiler implements
401	  these attributes, so make the config depend on CC_IS_CLANG.
402
403config PAHOLE_HAS_LANG_EXCLUDE
404	def_bool PAHOLE_VERSION >= 124
405	help
406	  Support for the --lang_exclude flag which makes pahole exclude
407	  compilation units from the supplied language. Used in Kbuild to
408	  omit Rust CUs which are not supported in version 1.24 of pahole,
409	  otherwise it would emit malformed kernel and module binaries when
410	  using DEBUG_INFO_BTF_MODULES.
411
412config DEBUG_INFO_BTF_MODULES
413	bool "Generate BTF type information for kernel modules"
414	default y
415	depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
416	help
417	  Generate compact split BTF type information for kernel modules.
418
419config MODULE_ALLOW_BTF_MISMATCH
420	bool "Allow loading modules with non-matching BTF type info"
421	depends on DEBUG_INFO_BTF_MODULES
422	help
423	  For modules whose split BTF does not match vmlinux, load without
424	  BTF rather than refusing to load. The default behavior with
425	  module BTF enabled is to reject modules with such mismatches;
426	  this option will still load module BTF where possible but ignore
427	  it when a mismatch is found.
428
429config GDB_SCRIPTS
430	bool "Provide GDB scripts for kernel debugging"
431	help
432	  This creates the required links to GDB helper scripts in the
433	  build directory. If you load vmlinux into gdb, the helper
434	  scripts will be automatically imported by gdb as well, and
435	  additional functions are available to analyze a Linux kernel
436	  instance. See Documentation/process/debugging/gdb-kernel-debugging.rst
437	  for further details.
438
439endif # DEBUG_INFO
440
441config FRAME_WARN
442	int "Warn for stack frames larger than"
443	range 0 8192
444	default 0 if KMSAN
445	default 2048 if GCC_PLUGIN_LATENT_ENTROPY
446	default 2048 if PARISC
447	default 1536 if (!64BIT && XTENSA)
448	default 1280 if KASAN && !64BIT
449	default 1024 if !64BIT
450	default 2048 if 64BIT
451	help
452	  Tell the compiler to warn at build time for stack frames larger than this.
453	  Setting this too low will cause a lot of warnings.
454	  Setting it to 0 disables the warning.
455
456config STRIP_ASM_SYMS
457	bool "Strip assembler-generated symbols during link"
458	default n
459	help
460	  Strip internal assembler-generated symbols during a link (symbols
461	  that look like '.Lxxx') so they don't pollute the output of
462	  get_wchan() and suchlike.
463
464config READABLE_ASM
465	bool "Generate readable assembler code"
466	depends on DEBUG_KERNEL
467	depends on CC_IS_GCC
468	help
469	  Disable some compiler optimizations that tend to generate human unreadable
470	  assembler output. This may make the kernel slightly slower, but it helps
471	  to keep kernel developers who have to stare a lot at assembler listings
472	  sane.
473
474config HEADERS_INSTALL
475	bool "Install uapi headers to usr/include"
476	depends on !UML
477	help
478	  This option will install uapi headers (headers exported to user-space)
479	  into the usr/include directory for use during the kernel build.
480	  This is unneeded for building the kernel itself, but needed for some
481	  user-space program samples. It is also needed by some features such
482	  as uapi header sanity checks.
483
484config DEBUG_SECTION_MISMATCH
485	bool "Enable full Section mismatch analysis"
486	depends on CC_IS_GCC
487	help
488	  The section mismatch analysis checks if there are illegal
489	  references from one section to another section.
490	  During linktime or runtime, some sections are dropped;
491	  any use of code/data previously in these sections would
492	  most likely result in an oops.
493	  In the code, functions and variables are annotated with
494	  __init,, etc. (see the full list in include/linux/init.h),
495	  which results in the code/data being placed in specific sections.
496	  The section mismatch analysis is always performed after a full
497	  kernel build, and enabling this option causes the following
498	  additional step to occur:
499	  - Add the option -fno-inline-functions-called-once to gcc commands.
500	    When inlining a function annotated with __init in a non-init
501	    function, we would lose the section information and thus
502	    the analysis would not catch the illegal reference.
503	    This option tells gcc to inline less (but it does result in
504	    a larger kernel).
505
506config SECTION_MISMATCH_WARN_ONLY
507	bool "Make section mismatch errors non-fatal"
508	default y
509	help
510	  If you say N here, the build process will fail if there are any
511	  section mismatch, instead of just throwing warnings.
512
513	  If unsure, say Y.
514
515config DEBUG_FORCE_FUNCTION_ALIGN_64B
516	bool "Force all function address 64B aligned"
517	depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC || RISCV || S390)
518	select FUNCTION_ALIGNMENT_64B
519	help
520	  There are cases that a commit from one domain changes the function
521	  address alignment of other domains, and cause magic performance
522	  bump (regression or improvement). Enable this option will help to
523	  verify if the bump is caused by function alignment changes, while
524	  it will slightly increase the kernel size and affect icache usage.
525
526	  It is mainly for debug and performance tuning use.
527
528#
529# Select this config option from the architecture Kconfig, if it
530# is preferred to always offer frame pointers as a config
531# option on the architecture (regardless of KERNEL_DEBUG):
532#
533config ARCH_WANT_FRAME_POINTERS
534	bool
535
536config FRAME_POINTER
537	bool "Compile the kernel with frame pointers"
538	depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
539	default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
540	help
541	  If you say Y here the resulting kernel image will be slightly
542	  larger and slower, but it gives very useful debugging information
543	  in case of kernel bugs. (precise oopses/stacktraces/warnings)
544
545config OBJTOOL
546	bool
547
548config OBJTOOL_WERROR
549	bool "Upgrade objtool warnings to errors"
550	depends on OBJTOOL && !COMPILE_TEST
551	help
552	  Fail the build on objtool warnings.
553
554	  Objtool warnings can indicate kernel instability, including boot
555	  failures.  This option is highly recommended.
556
557	  If unsure, say Y.
558
559config STACK_VALIDATION
560	bool "Compile-time stack metadata validation"
561	depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
562	select OBJTOOL
563	default n
564	help
565	  Validate frame pointer rules at compile-time.  This helps ensure that
566	  runtime stack traces are more reliable.
567
568	  For more information, see
569	  tools/objtool/Documentation/objtool.txt.
570
571config NOINSTR_VALIDATION
572	bool
573	depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
574	select OBJTOOL
575	default y
576
577config VMLINUX_MAP
578	bool "Generate vmlinux.map file when linking"
579	depends on EXPERT
580	help
581	  Selecting this option will pass "-Map=vmlinux.map" to ld
582	  when linking vmlinux. That file can be useful for verifying
583	  and debugging magic section games, and for seeing which
584	  pieces of code get eliminated with
585	  CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
586
587config BUILTIN_MODULE_RANGES
588	bool "Generate address range information for builtin modules"
589	depends on !LTO
590	depends on VMLINUX_MAP
591	help
592	 When modules are built into the kernel, there will be no module name
593	 associated with its symbols in /proc/kallsyms.  Tracers may want to
594	 identify symbols by module name and symbol name regardless of whether
595	 the module is configured as loadable or not.
596
597	 This option generates modules.builtin.ranges in the build tree with
598	 offset ranges (per ELF section) for the module(s) they belong to.
599	 It also records an anchor symbol to determine the load address of the
600	 section.
601
602config DEBUG_FORCE_WEAK_PER_CPU
603	bool "Force weak per-cpu definitions"
604	depends on DEBUG_KERNEL
605	help
606	  s390 and alpha require percpu variables in modules to be
607	  defined weak to work around addressing range issue which
608	  puts the following two restrictions on percpu variable
609	  definitions.
610
611	  1. percpu symbols must be unique whether static or not
612	  2. percpu variables can't be defined inside a function
613
614	  To ensure that generic code follows the above rules, this
615	  option forces all percpu variables to be defined as weak.
616
617endmenu # "Compiler options"
618
619menu "Generic Kernel Debugging Instruments"
620
621config MAGIC_SYSRQ
622	bool "Magic SysRq key"
623	depends on !UML
624	help
625	  If you say Y here, you will have some control over the system even
626	  if the system crashes for example during kernel debugging (e.g., you
627	  will be able to flush the buffer cache to disk, reboot the system
628	  immediately or dump some status information). This is accomplished
629	  by pressing various keys while holding SysRq (Alt+PrintScreen). It
630	  also works on a serial console (on PC hardware at least), if you
631	  send a BREAK and then within 5 seconds a command keypress. The
632	  keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
633	  Don't say Y unless you really know what this hack does.
634
635config MAGIC_SYSRQ_DEFAULT_ENABLE
636	hex "Enable magic SysRq key functions by default"
637	depends on MAGIC_SYSRQ
638	default 0x1
639	help
640	  Specifies which SysRq key functions are enabled by default.
641	  This may be set to 1 or 0 to enable or disable them all, or
642	  to a bitmask as described in Documentation/admin-guide/sysrq.rst.
643
644config MAGIC_SYSRQ_SERIAL
645	bool "Enable magic SysRq key over serial"
646	depends on MAGIC_SYSRQ
647	default y
648	help
649	  Many embedded boards have a disconnected TTL level serial which can
650	  generate some garbage that can lead to spurious false sysrq detects.
651	  This option allows you to decide whether you want to enable the
652	  magic SysRq key.
653
654config MAGIC_SYSRQ_SERIAL_SEQUENCE
655	string "Char sequence that enables magic SysRq over serial"
656	depends on MAGIC_SYSRQ_SERIAL
657	default ""
658	help
659	  Specifies a sequence of characters that can follow BREAK to enable
660	  SysRq on a serial console.
661
662	  If unsure, leave an empty string and the option will not be enabled.
663
664config DEBUG_FS
665	bool "Debug Filesystem"
666	help
667	  debugfs is a virtual file system that kernel developers use to put
668	  debugging files into.  Enable this option to be able to read and
669	  write to these files.
670
671	  For detailed documentation on the debugfs API, see
672	  Documentation/filesystems/.
673
674	  If unsure, say N.
675
676choice
677	prompt "Debugfs default access"
678	depends on DEBUG_FS
679	default DEBUG_FS_ALLOW_ALL
680	help
681	  This selects the default access restrictions for debugfs.
682	  It can be overridden with kernel command line option
683	  debugfs=[on,no-mount,off]. The restrictions apply for API access
684	  and filesystem registration.
685
686config DEBUG_FS_ALLOW_ALL
687	bool "Access normal"
688	help
689	  No restrictions apply. Both API and filesystem registration
690	  is on. This is the normal default operation.
691
692config DEBUG_FS_DISALLOW_MOUNT
693	bool "Do not register debugfs as filesystem"
694	help
695	  The API is open but filesystem is not loaded. Clients can still do
696	  their work and read with debug tools that do not need
697	  debugfs filesystem.
698
699config DEBUG_FS_ALLOW_NONE
700	bool "No access"
701	help
702	  Access is off. Clients get -PERM when trying to create nodes in
703	  debugfs tree and debugfs is not registered as a filesystem.
704	  Client can then back-off or continue without debugfs access.
705
706endchoice
707
708source "lib/Kconfig.kgdb"
709source "lib/Kconfig.ubsan"
710source "lib/Kconfig.kcsan"
711
712endmenu
713
714menu "Networking Debugging"
715
716source "net/Kconfig.debug"
717
718endmenu # "Networking Debugging"
719
720menu "Memory Debugging"
721
722source "mm/Kconfig.debug"
723
724config DEBUG_OBJECTS
725	bool "Debug object operations"
726	depends on DEBUG_KERNEL
727	help
728	  If you say Y here, additional code will be inserted into the
729	  kernel to track the life time of various objects and validate
730	  the operations on those objects.
731
732config DEBUG_OBJECTS_SELFTEST
733	bool "Debug objects selftest"
734	depends on DEBUG_OBJECTS
735	help
736	  This enables the selftest of the object debug code.
737
738config DEBUG_OBJECTS_FREE
739	bool "Debug objects in freed memory"
740	depends on DEBUG_OBJECTS
741	help
742	  This enables checks whether a k/v free operation frees an area
743	  which contains an object which has not been deactivated
744	  properly. This can make kmalloc/kfree-intensive workloads
745	  much slower.
746
747config DEBUG_OBJECTS_TIMERS
748	bool "Debug timer objects"
749	depends on DEBUG_OBJECTS
750	help
751	  If you say Y here, additional code will be inserted into the
752	  timer routines to track the life time of timer objects and
753	  validate the timer operations.
754
755config DEBUG_OBJECTS_WORK
756	bool "Debug work objects"
757	depends on DEBUG_OBJECTS
758	help
759	  If you say Y here, additional code will be inserted into the
760	  work queue routines to track the life time of work objects and
761	  validate the work operations.
762
763config DEBUG_OBJECTS_RCU_HEAD
764	bool "Debug RCU callbacks objects"
765	depends on DEBUG_OBJECTS
766	help
767	  Enable this to turn on debugging of RCU list heads (call_rcu() usage).
768
769config DEBUG_OBJECTS_PERCPU_COUNTER
770	bool "Debug percpu counter objects"
771	depends on DEBUG_OBJECTS
772	help
773	  If you say Y here, additional code will be inserted into the
774	  percpu counter routines to track the life time of percpu counter
775	  objects and validate the percpu counter operations.
776
777config DEBUG_OBJECTS_ENABLE_DEFAULT
778	int "debug_objects bootup default value (0-1)"
779	range 0 1
780	default "1"
781	depends on DEBUG_OBJECTS
782	help
783	  Debug objects boot parameter default value
784
785config SHRINKER_DEBUG
786	bool "Enable shrinker debugging support"
787	depends on DEBUG_FS
788	help
789	  Say Y to enable the shrinker debugfs interface which provides
790	  visibility into the kernel memory shrinkers subsystem.
791	  Disable it to avoid an extra memory footprint.
792
793config DEBUG_STACK_USAGE
794	bool "Stack utilization instrumentation"
795	depends on DEBUG_KERNEL
796	help
797	  Enables the display of the minimum amount of free stack which each
798	  task has ever had available in the sysrq-T and sysrq-P debug output.
799	  Also emits a message to dmesg when a process exits if that process
800	  used more stack space than previously exiting processes.
801
802	  This option will slow down process creation somewhat.
803
804config SCHED_STACK_END_CHECK
805	bool "Detect stack corruption on calls to schedule()"
806	depends on DEBUG_KERNEL
807	default n
808	help
809	  This option checks for a stack overrun on calls to schedule().
810	  If the stack end location is found to be over written always panic as
811	  the content of the corrupted region can no longer be trusted.
812	  This is to ensure no erroneous behaviour occurs which could result in
813	  data corruption or a sporadic crash at a later stage once the region
814	  is examined. The runtime overhead introduced is minimal.
815
816config ARCH_HAS_DEBUG_VM_PGTABLE
817	bool
818	help
819	  An architecture should select this when it can successfully
820	  build and run DEBUG_VM_PGTABLE.
821
822config DEBUG_VFS
823	bool "Debug VFS"
824	depends on DEBUG_KERNEL
825	help
826	  Enable this to turn on extended checks in the VFS layer that may impact
827	  performance.
828
829	  If unsure, say N.
830
831config DEBUG_VM_IRQSOFF
832	def_bool DEBUG_VM && !PREEMPT_RT
833
834config DEBUG_VM
835	bool "Debug VM"
836	depends on DEBUG_KERNEL
837	help
838	  Enable this to turn on extended checks in the virtual-memory system
839	  that may impact performance.
840
841	  If unsure, say N.
842
843config DEBUG_VM_SHOOT_LAZIES
844	bool "Debug MMU_LAZY_TLB_SHOOTDOWN implementation"
845	depends on DEBUG_VM
846	depends on MMU_LAZY_TLB_SHOOTDOWN
847	help
848	  Enable additional IPIs that ensure lazy tlb mm references are removed
849	  before the mm is freed.
850
851	  If unsure, say N.
852
853config DEBUG_VM_MAPLE_TREE
854	bool "Debug VM maple trees"
855	depends on DEBUG_VM
856	select DEBUG_MAPLE_TREE
857	help
858	  Enable VM maple tree debugging information and extra validations.
859
860	  If unsure, say N.
861
862config DEBUG_VM_RB
863	bool "Debug VM red-black trees"
864	depends on DEBUG_VM
865	help
866	  Enable VM red-black tree debugging information and extra validations.
867
868	  If unsure, say N.
869
870config DEBUG_VM_PGFLAGS
871	bool "Debug page-flags operations"
872	depends on DEBUG_VM
873	help
874	  Enables extra validation on page flags operations.
875
876	  If unsure, say N.
877
878config DEBUG_VM_PGTABLE
879	bool "Debug arch page table for semantics compliance"
880	depends on MMU
881	depends on ARCH_HAS_DEBUG_VM_PGTABLE
882	default y if DEBUG_VM
883	help
884	  This option provides a debug method which can be used to test
885	  architecture page table helper functions on various platforms in
886	  verifying if they comply with expected generic MM semantics. This
887	  will help architecture code in making sure that any changes or
888	  new additions of these helpers still conform to expected
889	  semantics of the generic MM. Platforms will have to opt in for
890	  this through ARCH_HAS_DEBUG_VM_PGTABLE.
891
892	  If unsure, say N.
893
894config ARCH_HAS_DEBUG_VIRTUAL
895	bool
896
897config DEBUG_VIRTUAL
898	bool "Debug VM translations"
899	depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
900	help
901	  Enable some costly sanity checks in virtual to page code. This can
902	  catch mistakes with virt_to_page() and friends.
903
904	  If unsure, say N.
905
906config DEBUG_NOMMU_REGIONS
907	bool "Debug the global anon/private NOMMU mapping region tree"
908	depends on DEBUG_KERNEL && !MMU
909	help
910	  This option causes the global tree of anonymous and private mapping
911	  regions to be regularly checked for invalid topology.
912
913config DEBUG_MEMORY_INIT
914	bool "Debug memory initialisation" if EXPERT
915	default !EXPERT
916	help
917	  Enable this for additional checks during memory initialisation.
918	  The sanity checks verify aspects of the VM such as the memory model
919	  and other information provided by the architecture. Verbose
920	  information will be printed at KERN_DEBUG loglevel depending
921	  on the mminit_loglevel= command-line option.
922
923	  If unsure, say Y
924
925config MEMORY_NOTIFIER_ERROR_INJECT
926	tristate "Memory hotplug notifier error injection module"
927	depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
928	help
929	  This option provides the ability to inject artificial errors to
930	  memory hotplug notifier chain callbacks.  It is controlled through
931	  debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
932
933	  If the notifier call chain should be failed with some events
934	  notified, write the error code to "actions/<notifier event>/error".
935
936	  Example: Inject memory hotplug offline error (-12 == -ENOMEM)
937
938	  # cd /sys/kernel/debug/notifier-error-inject/memory
939	  # echo -12 > actions/MEM_GOING_OFFLINE/error
940	  # echo offline > /sys/devices/system/memory/memoryXXX/state
941	  bash: echo: write error: Cannot allocate memory
942
943	  To compile this code as a module, choose M here: the module will
944	  be called memory-notifier-error-inject.
945
946	  If unsure, say N.
947
948config DEBUG_PER_CPU_MAPS
949	bool "Debug access to per_cpu maps"
950	depends on DEBUG_KERNEL
951	depends on SMP
952	help
953	  Say Y to verify that the per_cpu map being accessed has
954	  been set up. This adds a fair amount of code to kernel memory
955	  and decreases performance.
956
957	  Say N if unsure.
958
959config DEBUG_KMAP_LOCAL
960	bool "Debug kmap_local temporary mappings"
961	depends on DEBUG_KERNEL && KMAP_LOCAL
962	help
963	  This option enables additional error checking for the kmap_local
964	  infrastructure.  Disable for production use.
965
966config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
967	bool
968
969config DEBUG_KMAP_LOCAL_FORCE_MAP
970	bool "Enforce kmap_local temporary mappings"
971	depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
972	select KMAP_LOCAL
973	select DEBUG_KMAP_LOCAL
974	help
975	  This option enforces temporary mappings through the kmap_local
976	  mechanism for non-highmem pages and on non-highmem systems.
977	  Disable this for production systems!
978
979config DEBUG_HIGHMEM
980	bool "Highmem debugging"
981	depends on DEBUG_KERNEL && HIGHMEM
982	select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
983	select DEBUG_KMAP_LOCAL
984	help
985	  This option enables additional error checking for high memory
986	  systems.  Disable for production systems.
987
988config HAVE_DEBUG_STACKOVERFLOW
989	bool
990
991config DEBUG_STACKOVERFLOW
992	bool "Check for stack overflows"
993	depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
994	help
995	  Say Y here if you want to check for overflows of kernel, IRQ
996	  and exception stacks (if your architecture uses them). This
997	  option will show detailed messages if free stack space drops
998	  below a certain limit.
999
1000	  These kinds of bugs usually occur when call-chains in the
1001	  kernel get too deep, especially when interrupts are
1002	  involved.
1003
1004	  Use this in cases where you see apparently random memory
1005	  corruption, especially if it appears in 'struct thread_info'
1006
1007	  If in doubt, say "N".
1008
1009config CODE_TAGGING
1010	bool
1011	select KALLSYMS
1012
1013config MEM_ALLOC_PROFILING
1014	bool "Enable memory allocation profiling"
1015	default n
1016	depends on MMU
1017	depends on PROC_FS
1018	depends on !DEBUG_FORCE_WEAK_PER_CPU
1019	select CODE_TAGGING
1020	select PAGE_EXTENSION
1021	select SLAB_OBJ_EXT
1022	help
1023	  Track allocation source code and record total allocation size
1024	  initiated at that code location. The mechanism can be used to track
1025	  memory leaks with a low performance and memory impact.
1026
1027config MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
1028	bool "Enable memory allocation profiling by default"
1029	default y
1030	depends on MEM_ALLOC_PROFILING
1031
1032config MEM_ALLOC_PROFILING_DEBUG
1033	bool "Memory allocation profiler debugging"
1034	default n
1035	depends on MEM_ALLOC_PROFILING
1036	select MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
1037	help
1038	  Adds warnings with helpful error messages for memory allocation
1039	  profiling.
1040
1041source "lib/Kconfig.kasan"
1042source "lib/Kconfig.kfence"
1043source "lib/Kconfig.kmsan"
1044
1045endmenu # "Memory Debugging"
1046
1047config DEBUG_SHIRQ
1048	bool "Debug shared IRQ handlers"
1049	depends on DEBUG_KERNEL
1050	help
1051	  Enable this to generate a spurious interrupt just before a shared
1052	  interrupt handler is deregistered (generating one when registering
1053	  is currently disabled). Drivers need to handle this correctly. Some
1054	  don't and need to be caught.
1055
1056menu "Debug Oops, Lockups and Hangs"
1057
1058config PANIC_ON_OOPS
1059	bool "Panic on Oops"
1060	help
1061	  Say Y here to enable the kernel to panic when it oopses. This
1062	  has the same effect as setting oops=panic on the kernel command
1063	  line.
1064
1065	  This feature is useful to ensure that the kernel does not do
1066	  anything erroneous after an oops which could result in data
1067	  corruption or other issues.
1068
1069	  Say N if unsure.
1070
1071config PANIC_ON_OOPS_VALUE
1072	int
1073	range 0 1
1074	default 0 if !PANIC_ON_OOPS
1075	default 1 if PANIC_ON_OOPS
1076
1077config PANIC_TIMEOUT
1078	int "panic timeout"
1079	default 0
1080	help
1081	  Set the timeout value (in seconds) until a reboot occurs when
1082	  the kernel panics. If n = 0, then we wait forever. A timeout
1083	  value n > 0 will wait n seconds before rebooting, while a timeout
1084	  value n < 0 will reboot immediately. This setting can be overridden
1085	  with the kernel command line option panic=, and from userspace via
1086	  /proc/sys/kernel/panic.
1087
1088config LOCKUP_DETECTOR
1089	bool
1090
1091config SOFTLOCKUP_DETECTOR
1092	bool "Detect Soft Lockups"
1093	depends on DEBUG_KERNEL && !S390
1094	select LOCKUP_DETECTOR
1095	help
1096	  Say Y here to enable the kernel to act as a watchdog to detect
1097	  soft lockups.
1098
1099	  Softlockups are bugs that cause the kernel to loop in kernel
1100	  mode for more than 20 seconds, without giving other tasks a
1101	  chance to run.  The current stack trace is displayed upon
1102	  detection and the system will stay locked up.
1103
1104config SOFTLOCKUP_DETECTOR_INTR_STORM
1105	bool "Detect Interrupt Storm in Soft Lockups"
1106	depends on SOFTLOCKUP_DETECTOR && IRQ_TIME_ACCOUNTING
1107	select GENERIC_IRQ_STAT_SNAPSHOT
1108	default y if NR_CPUS <= 128
1109	help
1110	  Say Y here to enable the kernel to detect interrupt storm
1111	  during "soft lockups".
1112
1113	  "soft lockups" can be caused by a variety of reasons. If one is
1114	  caused by an interrupt storm, then the storming interrupts will not
1115	  be on the callstack. To detect this case, it is necessary to report
1116	  the CPU stats and the interrupt counts during the "soft lockups".
1117
1118config BOOTPARAM_SOFTLOCKUP_PANIC
1119	bool "Panic (Reboot) On Soft Lockups"
1120	depends on SOFTLOCKUP_DETECTOR
1121	help
1122	  Say Y here to enable the kernel to panic on "soft lockups",
1123	  which are bugs that cause the kernel to loop in kernel
1124	  mode for more than 20 seconds (configurable using the watchdog_thresh
1125	  sysctl), without giving other tasks a chance to run.
1126
1127	  The panic can be used in combination with panic_timeout,
1128	  to cause the system to reboot automatically after a
1129	  lockup has been detected. This feature is useful for
1130	  high-availability systems that have uptime guarantees and
1131	  where a lockup must be resolved ASAP.
1132
1133	  Say N if unsure.
1134
1135config HAVE_HARDLOCKUP_DETECTOR_BUDDY
1136	bool
1137	depends on SMP
1138	default y
1139
1140#
1141# Global switch whether to build a hardlockup detector at all. It is available
1142# only when the architecture supports at least one implementation. There are
1143# two exceptions. The hardlockup detector is never enabled on:
1144#
1145#	s390: it reported many false positives there
1146#
1147#	sparc64: has a custom implementation which is not using the common
1148#		hardlockup command line options and sysctl interface.
1149#
1150config HARDLOCKUP_DETECTOR
1151	bool "Detect Hard Lockups"
1152	depends on DEBUG_KERNEL && !S390 && !HARDLOCKUP_DETECTOR_SPARC64
1153	depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_BUDDY || HAVE_HARDLOCKUP_DETECTOR_ARCH
1154	imply HARDLOCKUP_DETECTOR_PERF
1155	imply HARDLOCKUP_DETECTOR_BUDDY
1156	imply HARDLOCKUP_DETECTOR_ARCH
1157	select LOCKUP_DETECTOR
1158
1159	help
1160	  Say Y here to enable the kernel to act as a watchdog to detect
1161	  hard lockups.
1162
1163	  Hardlockups are bugs that cause the CPU to loop in kernel mode
1164	  for more than 10 seconds, without letting other interrupts have a
1165	  chance to run.  The current stack trace is displayed upon detection
1166	  and the system will stay locked up.
1167
1168#
1169# Note that arch-specific variants are always preferred.
1170#
1171config HARDLOCKUP_DETECTOR_PREFER_BUDDY
1172	bool "Prefer the buddy CPU hardlockup detector"
1173	depends on HARDLOCKUP_DETECTOR
1174	depends on HAVE_HARDLOCKUP_DETECTOR_PERF && HAVE_HARDLOCKUP_DETECTOR_BUDDY
1175	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1176	help
1177	  Say Y here to prefer the buddy hardlockup detector over the perf one.
1178
1179	  With the buddy detector, each CPU uses its softlockup hrtimer
1180	  to check that the next CPU is processing hrtimer interrupts by
1181	  verifying that a counter is increasing.
1182
1183	  This hardlockup detector is useful on systems that don't have
1184	  an arch-specific hardlockup detector or if resources needed
1185	  for the hardlockup detector are better used for other things.
1186
1187config HARDLOCKUP_DETECTOR_PERF
1188	bool
1189	depends on HARDLOCKUP_DETECTOR
1190	depends on HAVE_HARDLOCKUP_DETECTOR_PERF && !HARDLOCKUP_DETECTOR_PREFER_BUDDY
1191	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1192	select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1193
1194config HARDLOCKUP_DETECTOR_BUDDY
1195	bool
1196	depends on HARDLOCKUP_DETECTOR
1197	depends on HAVE_HARDLOCKUP_DETECTOR_BUDDY
1198	depends on !HAVE_HARDLOCKUP_DETECTOR_PERF || HARDLOCKUP_DETECTOR_PREFER_BUDDY
1199	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1200	select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1201
1202config HARDLOCKUP_DETECTOR_ARCH
1203	bool
1204	depends on HARDLOCKUP_DETECTOR
1205	depends on HAVE_HARDLOCKUP_DETECTOR_ARCH
1206	help
1207	  The arch-specific implementation of the hardlockup detector will
1208	  be used.
1209
1210#
1211# Both the "perf" and "buddy" hardlockup detectors count hrtimer
1212# interrupts. This config enables functions managing this common code.
1213#
1214config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1215	bool
1216	select SOFTLOCKUP_DETECTOR
1217
1218#
1219# Enables a timestamp based low pass filter to compensate for perf based
1220# hard lockup detection which runs too fast due to turbo modes.
1221#
1222config HARDLOCKUP_CHECK_TIMESTAMP
1223	bool
1224
1225config BOOTPARAM_HARDLOCKUP_PANIC
1226	bool "Panic (Reboot) On Hard Lockups"
1227	depends on HARDLOCKUP_DETECTOR
1228	help
1229	  Say Y here to enable the kernel to panic on "hard lockups",
1230	  which are bugs that cause the kernel to loop in kernel
1231	  mode with interrupts disabled for more than 10 seconds (configurable
1232	  using the watchdog_thresh sysctl).
1233
1234	  Say N if unsure.
1235
1236config DETECT_HUNG_TASK
1237	bool "Detect Hung Tasks"
1238	depends on DEBUG_KERNEL
1239	default SOFTLOCKUP_DETECTOR
1240	help
1241	  Say Y here to enable the kernel to detect "hung tasks",
1242	  which are bugs that cause the task to be stuck in
1243	  uninterruptible "D" state indefinitely.
1244
1245	  When a hung task is detected, the kernel will print the
1246	  current stack trace (which you should report), but the
1247	  task will stay in uninterruptible state. If lockdep is
1248	  enabled then all held locks will also be reported. This
1249	  feature has negligible overhead.
1250
1251config DEFAULT_HUNG_TASK_TIMEOUT
1252	int "Default timeout for hung task detection (in seconds)"
1253	depends on DETECT_HUNG_TASK
1254	default 120
1255	help
1256	  This option controls the default timeout (in seconds) used
1257	  to determine when a task has become non-responsive and should
1258	  be considered hung.
1259
1260	  It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1261	  sysctl or by writing a value to
1262	  /proc/sys/kernel/hung_task_timeout_secs.
1263
1264	  A timeout of 0 disables the check.  The default is two minutes.
1265	  Keeping the default should be fine in most cases.
1266
1267config BOOTPARAM_HUNG_TASK_PANIC
1268	bool "Panic (Reboot) On Hung Tasks"
1269	depends on DETECT_HUNG_TASK
1270	help
1271	  Say Y here to enable the kernel to panic on "hung tasks",
1272	  which are bugs that cause the kernel to leave a task stuck
1273	  in uninterruptible "D" state.
1274
1275	  The panic can be used in combination with panic_timeout,
1276	  to cause the system to reboot automatically after a
1277	  hung task has been detected. This feature is useful for
1278	  high-availability systems that have uptime guarantees and
1279	  where a hung tasks must be resolved ASAP.
1280
1281	  Say N if unsure.
1282
1283config DETECT_HUNG_TASK_BLOCKER
1284	bool "Dump Hung Tasks Blocker"
1285	depends on DETECT_HUNG_TASK
1286	depends on !PREEMPT_RT
1287	default y
1288	help
1289	  Say Y here to show the blocker task's stacktrace who acquires
1290	  the mutex lock which "hung tasks" are waiting.
1291	  This will add overhead a bit but shows suspicious tasks and
1292	  call trace if it comes from waiting a mutex.
1293
1294config WQ_WATCHDOG
1295	bool "Detect Workqueue Stalls"
1296	depends on DEBUG_KERNEL
1297	help
1298	  Say Y here to enable stall detection on workqueues.  If a
1299	  worker pool doesn't make forward progress on a pending work
1300	  item for over a given amount of time, 30s by default, a
1301	  warning message is printed along with dump of workqueue
1302	  state.  This can be configured through kernel parameter
1303	  "workqueue.watchdog_thresh" and its sysfs counterpart.
1304
1305config WQ_CPU_INTENSIVE_REPORT
1306	bool "Report per-cpu work items which hog CPU for too long"
1307	depends on DEBUG_KERNEL
1308	help
1309	  Say Y here to enable reporting of concurrency-managed per-cpu work
1310	  items that hog CPUs for longer than
1311	  workqueue.cpu_intensive_thresh_us. Workqueue automatically
1312	  detects and excludes them from concurrency management to prevent
1313	  them from stalling other per-cpu work items. Occassional
1314	  triggering may not necessarily indicate a problem. Repeated
1315	  triggering likely indicates that the work item should be switched
1316	  to use an unbound workqueue.
1317
1318config TEST_LOCKUP
1319	tristate "Test module to generate lockups"
1320	depends on m
1321	help
1322	  This builds the "test_lockup" module that helps to make sure
1323	  that watchdogs and lockup detectors are working properly.
1324
1325	  Depending on module parameters it could emulate soft or hard
1326	  lockup, "hung task", or locking arbitrary lock for a long time.
1327	  Also it could generate series of lockups with cooling-down periods.
1328
1329	  If unsure, say N.
1330
1331endmenu # "Debug lockups and hangs"
1332
1333menu "Scheduler Debugging"
1334
1335config SCHED_INFO
1336	bool
1337	default n
1338
1339config SCHEDSTATS
1340	bool "Collect scheduler statistics"
1341	depends on PROC_FS
1342	select SCHED_INFO
1343	help
1344	  If you say Y here, additional code will be inserted into the
1345	  scheduler and related routines to collect statistics about
1346	  scheduler behavior and provide them in /proc/schedstat.  These
1347	  stats may be useful for both tuning and debugging the scheduler
1348	  If you aren't debugging the scheduler or trying to tune a specific
1349	  application, you can say N to avoid the very slight overhead
1350	  this adds.
1351
1352endmenu
1353
1354config DEBUG_PREEMPT
1355	bool "Debug preemptible kernel"
1356	depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1357	help
1358	  If you say Y here then the kernel will use a debug variant of the
1359	  commonly used smp_processor_id() function and will print warnings
1360	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
1361	  will detect preemption count underflows.
1362
1363	  This option has potential to introduce high runtime overhead,
1364	  depending on workload as it triggers debugging routines for each
1365	  this_cpu operation. It should only be used for debugging purposes.
1366
1367menu "Lock Debugging (spinlocks, mutexes, etc...)"
1368
1369config LOCK_DEBUGGING_SUPPORT
1370	bool
1371	depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1372	default y
1373
1374config PROVE_LOCKING
1375	bool "Lock debugging: prove locking correctness"
1376	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1377	select LOCKDEP
1378	select DEBUG_SPINLOCK
1379	select DEBUG_MUTEXES if !PREEMPT_RT
1380	select DEBUG_RT_MUTEXES if RT_MUTEXES
1381	select DEBUG_RWSEMS if !PREEMPT_RT
1382	select DEBUG_WW_MUTEX_SLOWPATH
1383	select DEBUG_LOCK_ALLOC
1384	select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1385	select TRACE_IRQFLAGS
1386	default n
1387	help
1388	 This feature enables the kernel to prove that all locking
1389	 that occurs in the kernel runtime is mathematically
1390	 correct: that under no circumstance could an arbitrary (and
1391	 not yet triggered) combination of observed locking
1392	 sequences (on an arbitrary number of CPUs, running an
1393	 arbitrary number of tasks and interrupt contexts) cause a
1394	 deadlock.
1395
1396	 In short, this feature enables the kernel to report locking
1397	 related deadlocks before they actually occur.
1398
1399	 The proof does not depend on how hard and complex a
1400	 deadlock scenario would be to trigger: how many
1401	 participant CPUs, tasks and irq-contexts would be needed
1402	 for it to trigger. The proof also does not depend on
1403	 timing: if a race and a resulting deadlock is possible
1404	 theoretically (no matter how unlikely the race scenario
1405	 is), it will be proven so and will immediately be
1406	 reported by the kernel (once the event is observed that
1407	 makes the deadlock theoretically possible).
1408
1409	 If a deadlock is impossible (i.e. the locking rules, as
1410	 observed by the kernel, are mathematically correct), the
1411	 kernel reports nothing.
1412
1413	 NOTE: this feature can also be enabled for rwlocks, mutexes
1414	 and rwsems - in which case all dependencies between these
1415	 different locking variants are observed and mapped too, and
1416	 the proof of observed correctness is also maintained for an
1417	 arbitrary combination of these separate locking variants.
1418
1419	 For more details, see Documentation/locking/lockdep-design.rst.
1420
1421config PROVE_RAW_LOCK_NESTING
1422	bool "Enable raw_spinlock - spinlock nesting checks" if !ARCH_SUPPORTS_RT
1423	depends on PROVE_LOCKING
1424	default y if ARCH_SUPPORTS_RT
1425	help
1426	 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1427	 that the lock nesting rules for PREEMPT_RT enabled kernels are
1428	 not violated.
1429
1430config LOCK_STAT
1431	bool "Lock usage statistics"
1432	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1433	select LOCKDEP
1434	select DEBUG_SPINLOCK
1435	select DEBUG_MUTEXES if !PREEMPT_RT
1436	select DEBUG_RT_MUTEXES if RT_MUTEXES
1437	select DEBUG_LOCK_ALLOC
1438	default n
1439	help
1440	 This feature enables tracking lock contention points
1441
1442	 For more details, see Documentation/locking/lockstat.rst
1443
1444	 This also enables lock events required by "perf lock",
1445	 subcommand of perf.
1446	 If you want to use "perf lock", you also need to turn on
1447	 CONFIG_EVENT_TRACING.
1448
1449	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1450	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1451
1452config DEBUG_RT_MUTEXES
1453	bool "RT Mutex debugging, deadlock detection"
1454	depends on DEBUG_KERNEL && RT_MUTEXES
1455	help
1456	 This allows rt mutex semantics violations and rt mutex related
1457	 deadlocks (lockups) to be detected and reported automatically.
1458
1459config DEBUG_SPINLOCK
1460	bool "Spinlock and rw-lock debugging: basic checks"
1461	depends on DEBUG_KERNEL
1462	select UNINLINE_SPIN_UNLOCK
1463	help
1464	  Say Y here and build SMP to catch missing spinlock initialization
1465	  and certain other kinds of spinlock errors commonly made.  This is
1466	  best used in conjunction with the NMI watchdog so that spinlock
1467	  deadlocks are also debuggable.
1468
1469config DEBUG_MUTEXES
1470	bool "Mutex debugging: basic checks"
1471	depends on DEBUG_KERNEL && !PREEMPT_RT
1472	help
1473	 This feature allows mutex semantics violations to be detected and
1474	 reported.
1475
1476config DEBUG_WW_MUTEX_SLOWPATH
1477	bool "Wait/wound mutex debugging: Slowpath testing"
1478	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1479	select DEBUG_LOCK_ALLOC
1480	select DEBUG_SPINLOCK
1481	select DEBUG_MUTEXES if !PREEMPT_RT
1482	select DEBUG_RT_MUTEXES if PREEMPT_RT
1483	help
1484	 This feature enables slowpath testing for w/w mutex users by
1485	 injecting additional -EDEADLK wound/backoff cases. Together with
1486	 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1487	 will test all possible w/w mutex interface abuse with the
1488	 exception of simply not acquiring all the required locks.
1489	 Note that this feature can introduce significant overhead, so
1490	 it really should not be enabled in a production or distro kernel,
1491	 even a debug kernel.  If you are a driver writer, enable it.  If
1492	 you are a distro, do not.
1493
1494config DEBUG_RWSEMS
1495	bool "RW Semaphore debugging: basic checks"
1496	depends on DEBUG_KERNEL && !PREEMPT_RT
1497	help
1498	  This debugging feature allows mismatched rw semaphore locks
1499	  and unlocks to be detected and reported.
1500
1501config DEBUG_LOCK_ALLOC
1502	bool "Lock debugging: detect incorrect freeing of live locks"
1503	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1504	select DEBUG_SPINLOCK
1505	select DEBUG_MUTEXES if !PREEMPT_RT
1506	select DEBUG_RT_MUTEXES if RT_MUTEXES
1507	select LOCKDEP
1508	help
1509	 This feature will check whether any held lock (spinlock, rwlock,
1510	 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1511	 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1512	 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1513	 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1514	 held during task exit.
1515
1516config LOCKDEP
1517	bool
1518	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1519	select STACKTRACE
1520	select KALLSYMS
1521	select KALLSYMS_ALL
1522
1523config LOCKDEP_SMALL
1524	bool
1525
1526config LOCKDEP_BITS
1527	int "Size for MAX_LOCKDEP_ENTRIES (as Nth power of 2)"
1528	depends on LOCKDEP && !LOCKDEP_SMALL
1529	range 10 24
1530	default 15
1531	help
1532	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1533
1534config LOCKDEP_CHAINS_BITS
1535	int "Size for MAX_LOCKDEP_CHAINS (as Nth power of 2)"
1536	depends on LOCKDEP && !LOCKDEP_SMALL
1537	range 10 21
1538	default 16
1539	help
1540	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1541
1542config LOCKDEP_STACK_TRACE_BITS
1543	int "Size for MAX_STACK_TRACE_ENTRIES (as Nth power of 2)"
1544	depends on LOCKDEP && !LOCKDEP_SMALL
1545	range 10 26
1546	default 19
1547	help
1548	  Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1549
1550config LOCKDEP_STACK_TRACE_HASH_BITS
1551	int "Size for STACK_TRACE_HASH_SIZE (as Nth power of 2)"
1552	depends on LOCKDEP && !LOCKDEP_SMALL
1553	range 10 26
1554	default 14
1555	help
1556	  Try increasing this value if you need large STACK_TRACE_HASH_SIZE.
1557
1558config LOCKDEP_CIRCULAR_QUEUE_BITS
1559	int "Size for elements in circular_queue struct (as Nth power of 2)"
1560	depends on LOCKDEP
1561	range 10 26
1562	default 12
1563	help
1564	  Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1565
1566config DEBUG_LOCKDEP
1567	bool "Lock dependency engine debugging"
1568	depends on DEBUG_KERNEL && LOCKDEP
1569	select DEBUG_IRQFLAGS
1570	help
1571	  If you say Y here, the lock dependency engine will do
1572	  additional runtime checks to debug itself, at the price
1573	  of more runtime overhead.
1574
1575config DEBUG_ATOMIC_SLEEP
1576	bool "Sleep inside atomic section checking"
1577	select PREEMPT_COUNT
1578	depends on DEBUG_KERNEL
1579	depends on !ARCH_NO_PREEMPT
1580	help
1581	  If you say Y here, various routines which may sleep will become very
1582	  noisy if they are called inside atomic sections: when a spinlock is
1583	  held, inside an rcu read side critical section, inside preempt disabled
1584	  sections, inside an interrupt, etc...
1585
1586config DEBUG_LOCKING_API_SELFTESTS
1587	bool "Locking API boot-time self-tests"
1588	depends on DEBUG_KERNEL
1589	help
1590	  Say Y here if you want the kernel to run a short self-test during
1591	  bootup. The self-test checks whether common types of locking bugs
1592	  are detected by debugging mechanisms or not. (if you disable
1593	  lock debugging then those bugs won't be detected of course.)
1594	  The following locking APIs are covered: spinlocks, rwlocks,
1595	  mutexes and rwsems.
1596
1597config LOCK_TORTURE_TEST
1598	tristate "torture tests for locking"
1599	depends on DEBUG_KERNEL
1600	select TORTURE_TEST
1601	help
1602	  This option provides a kernel module that runs torture tests
1603	  on kernel locking primitives.  The kernel module may be built
1604	  after the fact on the running kernel to be tested, if desired.
1605
1606	  Say Y here if you want kernel locking-primitive torture tests
1607	  to be built into the kernel.
1608	  Say M if you want these torture tests to build as a module.
1609	  Say N if you are unsure.
1610
1611config WW_MUTEX_SELFTEST
1612	tristate "Wait/wound mutex selftests"
1613	help
1614	  This option provides a kernel module that runs tests on the
1615	  on the struct ww_mutex locking API.
1616
1617	  It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1618	  with this test harness.
1619
1620	  Say M if you want these self tests to build as a module.
1621	  Say N if you are unsure.
1622
1623config SCF_TORTURE_TEST
1624	tristate "torture tests for smp_call_function*()"
1625	depends on DEBUG_KERNEL
1626	select TORTURE_TEST
1627	help
1628	  This option provides a kernel module that runs torture tests
1629	  on the smp_call_function() family of primitives.  The kernel
1630	  module may be built after the fact on the running kernel to
1631	  be tested, if desired.
1632
1633config CSD_LOCK_WAIT_DEBUG
1634	bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1635	depends on DEBUG_KERNEL
1636	depends on SMP
1637	depends on 64BIT
1638	default n
1639	help
1640	  This option enables debug prints when CPUs are slow to respond
1641	  to the smp_call_function*() IPI wrappers.  These debug prints
1642	  include the IPI handler function currently executing (if any)
1643	  and relevant stack traces.
1644
1645config CSD_LOCK_WAIT_DEBUG_DEFAULT
1646	bool "Default csd_lock_wait() debugging on at boot time"
1647	depends on CSD_LOCK_WAIT_DEBUG
1648	depends on 64BIT
1649	default n
1650	help
1651	  This option causes the csdlock_debug= kernel boot parameter to
1652	  default to 1 (basic debugging) instead of 0 (no debugging).
1653
1654endmenu # lock debugging
1655
1656config TRACE_IRQFLAGS
1657	depends on TRACE_IRQFLAGS_SUPPORT
1658	bool
1659	help
1660	  Enables hooks to interrupt enabling and disabling for
1661	  either tracing or lock debugging.
1662
1663config TRACE_IRQFLAGS_NMI
1664	def_bool y
1665	depends on TRACE_IRQFLAGS
1666	depends on TRACE_IRQFLAGS_NMI_SUPPORT
1667
1668config NMI_CHECK_CPU
1669	bool "Debugging for CPUs failing to respond to backtrace requests"
1670	depends on DEBUG_KERNEL
1671	depends on X86
1672	default n
1673	help
1674	  Enables debug prints when a CPU fails to respond to a given
1675	  backtrace NMI.  These prints provide some reasons why a CPU
1676	  might legitimately be failing to respond, for example, if it
1677	  is offline of if ignore_nmis is set.
1678
1679config DEBUG_IRQFLAGS
1680	bool "Debug IRQ flag manipulation"
1681	help
1682	  Enables checks for potentially unsafe enabling or disabling of
1683	  interrupts, such as calling raw_local_irq_restore() when interrupts
1684	  are enabled.
1685
1686config STACKTRACE
1687	bool "Stack backtrace support"
1688	depends on STACKTRACE_SUPPORT
1689	help
1690	  This option causes the kernel to create a /proc/pid/stack for
1691	  every process, showing its current stack trace.
1692	  It is also used by various kernel debugging features that require
1693	  stack trace generation.
1694
1695config WARN_ALL_UNSEEDED_RANDOM
1696	bool "Warn for all uses of unseeded randomness"
1697	default n
1698	help
1699	  Some parts of the kernel contain bugs relating to their use of
1700	  cryptographically secure random numbers before it's actually possible
1701	  to generate those numbers securely. This setting ensures that these
1702	  flaws don't go unnoticed, by enabling a message, should this ever
1703	  occur. This will allow people with obscure setups to know when things
1704	  are going wrong, so that they might contact developers about fixing
1705	  it.
1706
1707	  Unfortunately, on some models of some architectures getting
1708	  a fully seeded CRNG is extremely difficult, and so this can
1709	  result in dmesg getting spammed for a surprisingly long
1710	  time.  This is really bad from a security perspective, and
1711	  so architecture maintainers really need to do what they can
1712	  to get the CRNG seeded sooner after the system is booted.
1713	  However, since users cannot do anything actionable to
1714	  address this, by default this option is disabled.
1715
1716	  Say Y here if you want to receive warnings for all uses of
1717	  unseeded randomness.  This will be of use primarily for
1718	  those developers interested in improving the security of
1719	  Linux kernels running on their architecture (or
1720	  subarchitecture).
1721
1722config DEBUG_KOBJECT
1723	bool "kobject debugging"
1724	depends on DEBUG_KERNEL
1725	help
1726	  If you say Y here, some extra kobject debugging messages will be sent
1727	  to the syslog.
1728
1729config DEBUG_KOBJECT_RELEASE
1730	bool "kobject release debugging"
1731	depends on DEBUG_OBJECTS_TIMERS
1732	help
1733	  kobjects are reference counted objects.  This means that their
1734	  last reference count put is not predictable, and the kobject can
1735	  live on past the point at which a driver decides to drop its
1736	  initial reference to the kobject gained on allocation.  An
1737	  example of this would be a struct device which has just been
1738	  unregistered.
1739
1740	  However, some buggy drivers assume that after such an operation,
1741	  the memory backing the kobject can be immediately freed.  This
1742	  goes completely against the principles of a refcounted object.
1743
1744	  If you say Y here, the kernel will delay the release of kobjects
1745	  on the last reference count to improve the visibility of this
1746	  kind of kobject release bug.
1747
1748config HAVE_DEBUG_BUGVERBOSE
1749	bool
1750
1751menu "Debug kernel data structures"
1752
1753config DEBUG_LIST
1754	bool "Debug linked list manipulation"
1755	depends on DEBUG_KERNEL
1756	select LIST_HARDENED
1757	help
1758	  Enable this to turn on extended checks in the linked-list walking
1759	  routines.
1760
1761	  This option trades better quality error reports for performance, and
1762	  is more suitable for kernel debugging. If you care about performance,
1763	  you should only enable CONFIG_LIST_HARDENED instead.
1764
1765	  If unsure, say N.
1766
1767config DEBUG_PLIST
1768	bool "Debug priority linked list manipulation"
1769	depends on DEBUG_KERNEL
1770	help
1771	  Enable this to turn on extended checks in the priority-ordered
1772	  linked-list (plist) walking routines.  This checks the entire
1773	  list multiple times during each manipulation.
1774
1775	  If unsure, say N.
1776
1777config DEBUG_SG
1778	bool "Debug SG table operations"
1779	depends on DEBUG_KERNEL
1780	help
1781	  Enable this to turn on checks on scatter-gather tables. This can
1782	  help find problems with drivers that do not properly initialize
1783	  their sg tables.
1784
1785	  If unsure, say N.
1786
1787config DEBUG_NOTIFIERS
1788	bool "Debug notifier call chains"
1789	depends on DEBUG_KERNEL
1790	help
1791	  Enable this to turn on sanity checking for notifier call chains.
1792	  This is most useful for kernel developers to make sure that
1793	  modules properly unregister themselves from notifier chains.
1794	  This is a relatively cheap check but if you care about maximum
1795	  performance, say N.
1796
1797config DEBUG_CLOSURES
1798	bool "Debug closures (bcache async widgits)"
1799	depends on CLOSURES
1800	select DEBUG_FS
1801	help
1802	  Keeps all active closures in a linked list and provides a debugfs
1803	  interface to list them, which makes it possible to see asynchronous
1804	  operations that get stuck.
1805
1806config DEBUG_MAPLE_TREE
1807	bool "Debug maple trees"
1808	depends on DEBUG_KERNEL
1809	help
1810	  Enable maple tree debugging information and extra validations.
1811
1812	  If unsure, say N.
1813
1814endmenu
1815
1816source "kernel/rcu/Kconfig.debug"
1817
1818config DEBUG_WQ_FORCE_RR_CPU
1819	bool "Force round-robin CPU selection for unbound work items"
1820	depends on DEBUG_KERNEL
1821	default n
1822	help
1823	  Workqueue used to implicitly guarantee that work items queued
1824	  without explicit CPU specified are put on the local CPU.  This
1825	  guarantee is no longer true and while local CPU is still
1826	  preferred work items may be put on foreign CPUs.  Kernel
1827	  parameter "workqueue.debug_force_rr_cpu" is added to force
1828	  round-robin CPU selection to flush out usages which depend on the
1829	  now broken guarantee.  This config option enables the debug
1830	  feature by default.  When enabled, memory and cache locality will
1831	  be impacted.
1832
1833config CPU_HOTPLUG_STATE_CONTROL
1834	bool "Enable CPU hotplug state control"
1835	depends on DEBUG_KERNEL
1836	depends on HOTPLUG_CPU
1837	default n
1838	help
1839	  Allows to write steps between "offline" and "online" to the CPUs
1840	  sysfs target file so states can be stepped granular. This is a debug
1841	  option for now as the hotplug machinery cannot be stopped and
1842	  restarted at arbitrary points yet.
1843
1844	  Say N if your are unsure.
1845
1846config LATENCYTOP
1847	bool "Latency measuring infrastructure"
1848	depends on DEBUG_KERNEL
1849	depends on STACKTRACE_SUPPORT
1850	depends on PROC_FS
1851	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1852	select KALLSYMS
1853	select KALLSYMS_ALL
1854	select STACKTRACE
1855	select SCHEDSTATS
1856	help
1857	  Enable this option if you want to use the LatencyTOP tool
1858	  to find out which userspace is blocking on what kernel operations.
1859
1860config DEBUG_CGROUP_REF
1861	bool "Disable inlining of cgroup css reference count functions"
1862	depends on DEBUG_KERNEL
1863	depends on CGROUPS
1864	depends on KPROBES
1865	default n
1866	help
1867	  Force cgroup css reference count functions to not be inlined so
1868	  that they can be kprobed for debugging.
1869
1870source "kernel/trace/Kconfig"
1871
1872config PROVIDE_OHCI1394_DMA_INIT
1873	bool "Remote debugging over FireWire early on boot"
1874	depends on PCI && X86
1875	help
1876	  If you want to debug problems which hang or crash the kernel early
1877	  on boot and the crashing machine has a FireWire port, you can use
1878	  this feature to remotely access the memory of the crashed machine
1879	  over FireWire. This employs remote DMA as part of the OHCI1394
1880	  specification which is now the standard for FireWire controllers.
1881
1882	  With remote DMA, you can monitor the printk buffer remotely using
1883	  firescope and access all memory below 4GB using fireproxy from gdb.
1884	  Even controlling a kernel debugger is possible using remote DMA.
1885
1886	  Usage:
1887
1888	  If ohci1394_dma=early is used as boot parameter, it will initialize
1889	  all OHCI1394 controllers which are found in the PCI config space.
1890
1891	  As all changes to the FireWire bus such as enabling and disabling
1892	  devices cause a bus reset and thereby disable remote DMA for all
1893	  devices, be sure to have the cable plugged and FireWire enabled on
1894	  the debugging host before booting the debug target for debugging.
1895
1896	  This code (~1k) is freed after boot. By then, the firewire stack
1897	  in charge of the OHCI-1394 controllers should be used instead.
1898
1899	  See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1900
1901source "samples/Kconfig"
1902
1903config ARCH_HAS_DEVMEM_IS_ALLOWED
1904	bool
1905
1906config STRICT_DEVMEM
1907	bool "Filter access to /dev/mem"
1908	depends on MMU && DEVMEM
1909	depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1910	default y if PPC || X86 || ARM64 || S390
1911	help
1912	  If this option is disabled, you allow userspace (root) access to all
1913	  of memory, including kernel and userspace memory. Accidental
1914	  access to this is obviously disastrous, but specific access can
1915	  be used by people debugging the kernel. Note that with PAT support
1916	  enabled, even in this case there are restrictions on /dev/mem
1917	  use due to the cache aliasing requirements.
1918
1919	  If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1920	  file only allows userspace access to PCI space and the BIOS code and
1921	  data regions.  This is sufficient for dosemu and X and all common
1922	  users of /dev/mem.
1923
1924	  If in doubt, say Y.
1925
1926config IO_STRICT_DEVMEM
1927	bool "Filter I/O access to /dev/mem"
1928	depends on STRICT_DEVMEM
1929	help
1930	  If this option is disabled, you allow userspace (root) access to all
1931	  io-memory regardless of whether a driver is actively using that
1932	  range.  Accidental access to this is obviously disastrous, but
1933	  specific access can be used by people debugging kernel drivers.
1934
1935	  If this option is switched on, the /dev/mem file only allows
1936	  userspace access to *idle* io-memory ranges (see /proc/iomem) This
1937	  may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1938	  if the driver using a given range cannot be disabled.
1939
1940	  If in doubt, say Y.
1941
1942menu "$(SRCARCH) Debugging"
1943
1944source "arch/$(SRCARCH)/Kconfig.debug"
1945
1946endmenu
1947
1948menu "Kernel Testing and Coverage"
1949
1950source "lib/kunit/Kconfig"
1951
1952config NOTIFIER_ERROR_INJECTION
1953	tristate "Notifier error injection"
1954	depends on DEBUG_KERNEL
1955	select DEBUG_FS
1956	help
1957	  This option provides the ability to inject artificial errors to
1958	  specified notifier chain callbacks. It is useful to test the error
1959	  handling of notifier call chain failures.
1960
1961	  Say N if unsure.
1962
1963config PM_NOTIFIER_ERROR_INJECT
1964	tristate "PM notifier error injection module"
1965	depends on PM && NOTIFIER_ERROR_INJECTION
1966	default m if PM_DEBUG
1967	help
1968	  This option provides the ability to inject artificial errors to
1969	  PM notifier chain callbacks.  It is controlled through debugfs
1970	  interface /sys/kernel/debug/notifier-error-inject/pm
1971
1972	  If the notifier call chain should be failed with some events
1973	  notified, write the error code to "actions/<notifier event>/error".
1974
1975	  Example: Inject PM suspend error (-12 = -ENOMEM)
1976
1977	  # cd /sys/kernel/debug/notifier-error-inject/pm/
1978	  # echo -12 > actions/PM_SUSPEND_PREPARE/error
1979	  # echo mem > /sys/power/state
1980	  bash: echo: write error: Cannot allocate memory
1981
1982	  To compile this code as a module, choose M here: the module will
1983	  be called pm-notifier-error-inject.
1984
1985	  If unsure, say N.
1986
1987config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1988	tristate "OF reconfig notifier error injection module"
1989	depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1990	help
1991	  This option provides the ability to inject artificial errors to
1992	  OF reconfig notifier chain callbacks.  It is controlled
1993	  through debugfs interface under
1994	  /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1995
1996	  If the notifier call chain should be failed with some events
1997	  notified, write the error code to "actions/<notifier event>/error".
1998
1999	  To compile this code as a module, choose M here: the module will
2000	  be called of-reconfig-notifier-error-inject.
2001
2002	  If unsure, say N.
2003
2004config NETDEV_NOTIFIER_ERROR_INJECT
2005	tristate "Netdev notifier error injection module"
2006	depends on NET && NOTIFIER_ERROR_INJECTION
2007	help
2008	  This option provides the ability to inject artificial errors to
2009	  netdevice notifier chain callbacks.  It is controlled through debugfs
2010	  interface /sys/kernel/debug/notifier-error-inject/netdev
2011
2012	  If the notifier call chain should be failed with some events
2013	  notified, write the error code to "actions/<notifier event>/error".
2014
2015	  Example: Inject netdevice mtu change error (-22 = -EINVAL)
2016
2017	  # cd /sys/kernel/debug/notifier-error-inject/netdev
2018	  # echo -22 > actions/NETDEV_CHANGEMTU/error
2019	  # ip link set eth0 mtu 1024
2020	  RTNETLINK answers: Invalid argument
2021
2022	  To compile this code as a module, choose M here: the module will
2023	  be called netdev-notifier-error-inject.
2024
2025	  If unsure, say N.
2026
2027config FUNCTION_ERROR_INJECTION
2028	bool "Fault-injections of functions"
2029	depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
2030	help
2031	  Add fault injections into various functions that are annotated with
2032	  ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
2033	  value of these functions. This is useful to test error paths of code.
2034
2035	  If unsure, say N
2036
2037config FAULT_INJECTION
2038	bool "Fault-injection framework"
2039	depends on DEBUG_KERNEL
2040	help
2041	  Provide fault-injection framework.
2042	  For more details, see Documentation/fault-injection/.
2043
2044config FAILSLAB
2045	bool "Fault-injection capability for kmalloc"
2046	depends on FAULT_INJECTION
2047	help
2048	  Provide fault-injection capability for kmalloc.
2049
2050config FAIL_PAGE_ALLOC
2051	bool "Fault-injection capability for alloc_pages()"
2052	depends on FAULT_INJECTION
2053	help
2054	  Provide fault-injection capability for alloc_pages().
2055
2056config FAULT_INJECTION_USERCOPY
2057	bool "Fault injection capability for usercopy functions"
2058	depends on FAULT_INJECTION
2059	help
2060	  Provides fault-injection capability to inject failures
2061	  in usercopy functions (copy_from_user(), get_user(), ...).
2062
2063config FAIL_MAKE_REQUEST
2064	bool "Fault-injection capability for disk IO"
2065	depends on FAULT_INJECTION && BLOCK
2066	help
2067	  Provide fault-injection capability for disk IO.
2068
2069config FAIL_IO_TIMEOUT
2070	bool "Fault-injection capability for faking disk interrupts"
2071	depends on FAULT_INJECTION && BLOCK
2072	help
2073	  Provide fault-injection capability on end IO handling. This
2074	  will make the block layer "forget" an interrupt as configured,
2075	  thus exercising the error handling.
2076
2077	  Only works with drivers that use the generic timeout handling,
2078	  for others it won't do anything.
2079
2080config FAIL_FUTEX
2081	bool "Fault-injection capability for futexes"
2082	select DEBUG_FS
2083	depends on FAULT_INJECTION && FUTEX
2084	help
2085	  Provide fault-injection capability for futexes.
2086
2087config FAULT_INJECTION_DEBUG_FS
2088	bool "Debugfs entries for fault-injection capabilities"
2089	depends on FAULT_INJECTION && SYSFS && DEBUG_FS
2090	help
2091	  Enable configuration of fault-injection capabilities via debugfs.
2092
2093config FAIL_FUNCTION
2094	bool "Fault-injection capability for functions"
2095	depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
2096	help
2097	  Provide function-based fault-injection capability.
2098	  This will allow you to override a specific function with a return
2099	  with given return value. As a result, function caller will see
2100	  an error value and have to handle it. This is useful to test the
2101	  error handling in various subsystems.
2102
2103config FAIL_MMC_REQUEST
2104	bool "Fault-injection capability for MMC IO"
2105	depends on FAULT_INJECTION_DEBUG_FS && MMC
2106	help
2107	  Provide fault-injection capability for MMC IO.
2108	  This will make the mmc core return data errors. This is
2109	  useful to test the error handling in the mmc block device
2110	  and to test how the mmc host driver handles retries from
2111	  the block device.
2112
2113config FAIL_SUNRPC
2114	bool "Fault-injection capability for SunRPC"
2115	depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2116	help
2117	  Provide fault-injection capability for SunRPC and
2118	  its consumers.
2119
2120config FAIL_SKB_REALLOC
2121	bool "Fault-injection capability forcing skb to reallocate"
2122	depends on FAULT_INJECTION_DEBUG_FS
2123	help
2124	  Provide fault-injection capability that forces the skb to be
2125	  reallocated, catching possible invalid pointers to the skb.
2126
2127	  For more information, check
2128	  Documentation/fault-injection/fault-injection.rst
2129
2130config FAULT_INJECTION_CONFIGFS
2131	bool "Configfs interface for fault-injection capabilities"
2132	depends on FAULT_INJECTION
2133	select CONFIGFS_FS
2134	help
2135	  This option allows configfs-based drivers to dynamically configure
2136	  fault-injection via configfs.  Each parameter for driver-specific
2137	  fault-injection can be made visible as a configfs attribute in a
2138	  configfs group.
2139
2140
2141config FAULT_INJECTION_STACKTRACE_FILTER
2142	bool "stacktrace filter for fault-injection capabilities"
2143	depends on FAULT_INJECTION
2144	depends on (FAULT_INJECTION_DEBUG_FS || FAULT_INJECTION_CONFIGFS) && STACKTRACE_SUPPORT
2145	select STACKTRACE
2146	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2147	help
2148	  Provide stacktrace filter for fault-injection capabilities
2149
2150config ARCH_HAS_KCOV
2151	bool
2152	help
2153	  An architecture should select this when it can successfully
2154	  build and run with CONFIG_KCOV. This typically requires
2155	  disabling instrumentation for some early boot code.
2156
2157config CC_HAS_SANCOV_TRACE_PC
2158	def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2159
2160
2161config KCOV
2162	bool "Code coverage for fuzzing"
2163	depends on ARCH_HAS_KCOV
2164	depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2165	depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2166		   GCC_VERSION >= 120000 || CC_IS_CLANG
2167	select DEBUG_FS
2168	select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2169	select OBJTOOL if HAVE_NOINSTR_HACK
2170	help
2171	  KCOV exposes kernel code coverage information in a form suitable
2172	  for coverage-guided fuzzing (randomized testing).
2173
2174	  For more details, see Documentation/dev-tools/kcov.rst.
2175
2176config KCOV_ENABLE_COMPARISONS
2177	bool "Enable comparison operands collection by KCOV"
2178	depends on KCOV
2179	depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2180	help
2181	  KCOV also exposes operands of every comparison in the instrumented
2182	  code along with operand sizes and PCs of the comparison instructions.
2183	  These operands can be used by fuzzing engines to improve the quality
2184	  of fuzzing coverage.
2185
2186config KCOV_INSTRUMENT_ALL
2187	bool "Instrument all code by default"
2188	depends on KCOV
2189	default y
2190	help
2191	  If you are doing generic system call fuzzing (like e.g. syzkaller),
2192	  then you will want to instrument the whole kernel and you should
2193	  say y here. If you are doing more targeted fuzzing (like e.g.
2194	  filesystem fuzzing with AFL) then you will want to enable coverage
2195	  for more specific subsets of files, and should say n here.
2196
2197config KCOV_IRQ_AREA_SIZE
2198	hex "Size of interrupt coverage collection area in words"
2199	depends on KCOV
2200	default 0x40000
2201	help
2202	  KCOV uses preallocated per-cpu areas to collect coverage from
2203	  soft interrupts. This specifies the size of those areas in the
2204	  number of unsigned long words.
2205
2206config KCOV_SELFTEST
2207	bool "Perform short selftests on boot"
2208	depends on KCOV
2209	help
2210	  Run short KCOV coverage collection selftests on boot.
2211	  On test failure, causes the kernel to panic. Recommended to be
2212	  enabled, ensuring critical functionality works as intended.
2213
2214menuconfig RUNTIME_TESTING_MENU
2215	bool "Runtime Testing"
2216	default y
2217
2218if RUNTIME_TESTING_MENU
2219
2220config TEST_DHRY
2221	tristate "Dhrystone benchmark test"
2222	help
2223	  Enable this to include the Dhrystone 2.1 benchmark.  This test
2224	  calculates the number of Dhrystones per second, and the number of
2225	  DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided
2226	  by 1757 (the number of Dhrystones per second obtained on the VAX
2227	  11/780, nominally a 1 MIPS machine).
2228
2229	  To run the benchmark, it needs to be enabled explicitly, either from
2230	  the kernel command line (when built-in), or from userspace (when
2231	  built-in or modular).
2232
2233	  Run once during kernel boot:
2234
2235	      test_dhry.run
2236
2237	  Set number of iterations from kernel command line:
2238
2239	      test_dhry.iterations=<n>
2240
2241	  Set number of iterations from userspace:
2242
2243	      echo <n> > /sys/module/test_dhry/parameters/iterations
2244
2245	  Trigger manual run from userspace:
2246
2247	      echo y > /sys/module/test_dhry/parameters/run
2248
2249	  If the number of iterations is <= 0, the test will devise a suitable
2250	  number of iterations (test runs for at least 2s) automatically.
2251	  This process takes ca. 4s.
2252
2253	  If unsure, say N.
2254
2255config LKDTM
2256	tristate "Linux Kernel Dump Test Tool Module"
2257	depends on DEBUG_FS
2258	help
2259	This module enables testing of the different dumping mechanisms by
2260	inducing system failures at predefined crash points.
2261	If you don't need it: say N
2262	Choose M here to compile this code as a module. The module will be
2263	called lkdtm.
2264
2265	Documentation on how to use the module can be found in
2266	Documentation/fault-injection/provoke-crashes.rst
2267
2268config CPUMASK_KUNIT_TEST
2269	tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2270	depends on KUNIT
2271	default KUNIT_ALL_TESTS
2272	help
2273	  Enable to turn on cpumask tests, running at boot or module load time.
2274
2275	  For more information on KUnit and unit tests in general, please refer
2276	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2277
2278	  If unsure, say N.
2279
2280config TEST_LIST_SORT
2281	tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2282	depends on KUNIT
2283	default KUNIT_ALL_TESTS
2284	help
2285	  Enable this to turn on 'list_sort()' function test. This test is
2286	  executed only once during system boot (so affects only boot time),
2287	  or at module load time.
2288
2289	  If unsure, say N.
2290
2291config TEST_MIN_HEAP
2292	tristate "Min heap test"
2293	depends on DEBUG_KERNEL || m
2294	help
2295	  Enable this to turn on min heap function tests. This test is
2296	  executed only once during system boot (so affects only boot time),
2297	  or at module load time.
2298
2299	  If unsure, say N.
2300
2301config TEST_SORT
2302	tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2303	depends on KUNIT
2304	default KUNIT_ALL_TESTS
2305	help
2306	  This option enables the self-test function of 'sort()' at boot,
2307	  or at module load time.
2308
2309	  If unsure, say N.
2310
2311config TEST_DIV64
2312	tristate "64bit/32bit division and modulo test"
2313	depends on DEBUG_KERNEL || m
2314	help
2315	  Enable this to turn on 'do_div()' function test. This test is
2316	  executed only once during system boot (so affects only boot time),
2317	  or at module load time.
2318
2319	  If unsure, say N.
2320
2321config TEST_MULDIV64
2322	tristate "mul_u64_u64_div_u64() test"
2323	depends on DEBUG_KERNEL || m
2324	help
2325	  Enable this to turn on 'mul_u64_u64_div_u64()' function test.
2326	  This test is executed only once during system boot (so affects
2327	  only boot time), or at module load time.
2328
2329	  If unsure, say N.
2330
2331config TEST_IOV_ITER
2332	tristate "Test iov_iter operation" if !KUNIT_ALL_TESTS
2333	depends on KUNIT
2334	depends on MMU
2335	default KUNIT_ALL_TESTS
2336	help
2337	  Enable this to turn on testing of the operation of the I/O iterator
2338	  (iov_iter). This test is executed only once during system boot (so
2339	  affects only boot time), or at module load time.
2340
2341	  If unsure, say N.
2342
2343config KPROBES_SANITY_TEST
2344	tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2345	depends on DEBUG_KERNEL
2346	depends on KPROBES
2347	depends on KUNIT
2348	select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2349	default KUNIT_ALL_TESTS
2350	help
2351	  This option provides for testing basic kprobes functionality on
2352	  boot. Samples of kprobe and kretprobe are inserted and
2353	  verified for functionality.
2354
2355	  Say N if you are unsure.
2356
2357config FPROBE_SANITY_TEST
2358	bool "Self test for fprobe"
2359	depends on DEBUG_KERNEL
2360	depends on FPROBE
2361	depends on KUNIT=y
2362	help
2363	  This option will enable testing the fprobe when the system boot.
2364	  A series of tests are made to verify that the fprobe is functioning
2365	  properly.
2366
2367	  Say N if you are unsure.
2368
2369config BACKTRACE_SELF_TEST
2370	tristate "Self test for the backtrace code"
2371	depends on DEBUG_KERNEL
2372	help
2373	  This option provides a kernel module that can be used to test
2374	  the kernel stack backtrace code. This option is not useful
2375	  for distributions or general kernels, but only for kernel
2376	  developers working on architecture code.
2377
2378	  Note that if you want to also test saved backtraces, you will
2379	  have to enable STACKTRACE as well.
2380
2381	  Say N if you are unsure.
2382
2383config TEST_REF_TRACKER
2384	tristate "Self test for reference tracker"
2385	depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2386	select REF_TRACKER
2387	help
2388	  This option provides a kernel module performing tests
2389	  using reference tracker infrastructure.
2390
2391	  Say N if you are unsure.
2392
2393config RBTREE_TEST
2394	tristate "Red-Black tree test"
2395	depends on DEBUG_KERNEL
2396	help
2397	  A benchmark measuring the performance of the rbtree library.
2398	  Also includes rbtree invariant checks.
2399
2400config REED_SOLOMON_TEST
2401	tristate "Reed-Solomon library test"
2402	depends on DEBUG_KERNEL || m
2403	select REED_SOLOMON
2404	select REED_SOLOMON_ENC16
2405	select REED_SOLOMON_DEC16
2406	help
2407	  This option enables the self-test function of rslib at boot,
2408	  or at module load time.
2409
2410	  If unsure, say N.
2411
2412config INTERVAL_TREE_TEST
2413	tristate "Interval tree test"
2414	depends on DEBUG_KERNEL
2415	select INTERVAL_TREE
2416	help
2417	  A benchmark measuring the performance of the interval tree library
2418
2419config PERCPU_TEST
2420	tristate "Per cpu operations test"
2421	depends on m && DEBUG_KERNEL
2422	help
2423	  Enable this option to build test module which validates per-cpu
2424	  operations.
2425
2426	  If unsure, say N.
2427
2428config ATOMIC64_SELFTEST
2429	tristate "Perform an atomic64_t self-test"
2430	help
2431	  Enable this option to test the atomic64_t functions at boot or
2432	  at module load time.
2433
2434	  If unsure, say N.
2435
2436config ASYNC_RAID6_TEST
2437	tristate "Self test for hardware accelerated raid6 recovery"
2438	depends on ASYNC_RAID6_RECOV
2439	select ASYNC_MEMCPY
2440	help
2441	  This is a one-shot self test that permutes through the
2442	  recovery of all the possible two disk failure scenarios for a
2443	  N-disk array.  Recovery is performed with the asynchronous
2444	  raid6 recovery routines, and will optionally use an offload
2445	  engine if one is available.
2446
2447	  If unsure, say N.
2448
2449config TEST_HEXDUMP
2450	tristate "Test functions located in the hexdump module at runtime"
2451
2452config PRINTF_KUNIT_TEST
2453	tristate "KUnit test printf() family of functions at runtime" if !KUNIT_ALL_TESTS
2454	depends on KUNIT
2455	default KUNIT_ALL_TESTS
2456	help
2457	  Enable this option to test the printf functions at runtime.
2458
2459	  If unsure, say N.
2460
2461config SCANF_KUNIT_TEST
2462	tristate "KUnit test scanf() family of functions at runtime" if !KUNIT_ALL_TESTS
2463	depends on KUNIT
2464	default KUNIT_ALL_TESTS
2465	help
2466	  Enable this option to test the scanf functions at runtime.
2467
2468	  If unsure, say N.
2469
2470config STRING_KUNIT_TEST
2471	tristate "KUnit test string functions at runtime" if !KUNIT_ALL_TESTS
2472	depends on KUNIT
2473	default KUNIT_ALL_TESTS
2474
2475config STRING_HELPERS_KUNIT_TEST
2476	tristate "KUnit test string helpers at runtime" if !KUNIT_ALL_TESTS
2477	depends on KUNIT
2478	default KUNIT_ALL_TESTS
2479
2480config TEST_KSTRTOX
2481	tristate "Test kstrto*() family of functions at runtime"
2482
2483config TEST_BITMAP
2484	tristate "Test bitmap_*() family of functions at runtime"
2485	help
2486	  Enable this option to test the bitmap functions at boot.
2487
2488	  If unsure, say N.
2489
2490config TEST_UUID
2491	tristate "Test functions located in the uuid module at runtime"
2492
2493config TEST_XARRAY
2494	tristate "Test the XArray code at runtime"
2495
2496config TEST_MAPLE_TREE
2497	tristate "Test the Maple Tree code at runtime or module load"
2498	help
2499	  Enable this option to test the maple tree code functions at boot, or
2500	  when the module is loaded. Enable "Debug Maple Trees" will enable
2501	  more verbose output on failures.
2502
2503	  If unsure, say N.
2504
2505config TEST_RHASHTABLE
2506	tristate "Perform selftest on resizable hash table"
2507	help
2508	  Enable this option to test the rhashtable functions at boot.
2509
2510	  If unsure, say N.
2511
2512config TEST_IDA
2513	tristate "Perform selftest on IDA functions"
2514
2515config TEST_MISC_MINOR
2516	tristate "Basic misc minor Kunit test" if !KUNIT_ALL_TESTS
2517	depends on KUNIT
2518	default KUNIT_ALL_TESTS
2519	help
2520	  Kunit test for the misc minor.
2521	  It tests misc minor functions for dynamic and misc dynamic minor.
2522	  This include misc_xxx functions
2523
2524	  If unsure, say N.
2525
2526config TEST_PARMAN
2527	tristate "Perform selftest on priority array manager"
2528	depends on PARMAN
2529	help
2530	  Enable this option to test priority array manager on boot
2531	  (or module load).
2532
2533	  If unsure, say N.
2534
2535config TEST_IRQ_TIMINGS
2536	bool "IRQ timings selftest"
2537	depends on IRQ_TIMINGS
2538	help
2539	  Enable this option to test the irq timings code on boot.
2540
2541	  If unsure, say N.
2542
2543config TEST_LKM
2544	tristate "Test module loading with 'hello world' module"
2545	depends on m
2546	help
2547	  This builds the "test_module" module that emits "Hello, world"
2548	  on printk when loaded. It is designed to be used for basic
2549	  evaluation of the module loading subsystem (for example when
2550	  validating module verification). It lacks any extra dependencies,
2551	  and will not normally be loaded by the system unless explicitly
2552	  requested by name.
2553
2554	  If unsure, say N.
2555
2556config TEST_BITOPS
2557	tristate "Test module for compilation of bitops operations"
2558	help
2559	  This builds the "test_bitops" module that is much like the
2560	  TEST_LKM module except that it does a basic exercise of the
2561	  set/clear_bit macros and get_count_order/long to make sure there are
2562	  no compiler warnings from C=1 sparse checker or -Wextra
2563	  compilations. It has no dependencies and doesn't run or load unless
2564	  explicitly requested by name.  for example: modprobe test_bitops.
2565
2566	  If unsure, say N.
2567
2568config TEST_VMALLOC
2569	tristate "Test module for stress/performance analysis of vmalloc allocator"
2570	default n
2571       depends on MMU
2572	depends on m
2573	help
2574	  This builds the "test_vmalloc" module that should be used for
2575	  stress and performance analysis. So, any new change for vmalloc
2576	  subsystem can be evaluated from performance and stability point
2577	  of view.
2578
2579	  If unsure, say N.
2580
2581config TEST_BPF
2582	tristate "Test BPF filter functionality"
2583	depends on m && NET
2584	help
2585	  This builds the "test_bpf" module that runs various test vectors
2586	  against the BPF interpreter or BPF JIT compiler depending on the
2587	  current setting. This is in particular useful for BPF JIT compiler
2588	  development, but also to run regression tests against changes in
2589	  the interpreter code. It also enables test stubs for eBPF maps and
2590	  verifier used by user space verifier testsuite.
2591
2592	  If unsure, say N.
2593
2594config FIND_BIT_BENCHMARK
2595	tristate "Test find_bit functions"
2596	help
2597	  This builds the "test_find_bit" module that measure find_*_bit()
2598	  functions performance.
2599
2600	  If unsure, say N.
2601
2602config TEST_FIRMWARE
2603	tristate "Test firmware loading via userspace interface"
2604	depends on FW_LOADER
2605	help
2606	  This builds the "test_firmware" module that creates a userspace
2607	  interface for testing firmware loading. This can be used to
2608	  control the triggering of firmware loading without needing an
2609	  actual firmware-using device. The contents can be rechecked by
2610	  userspace.
2611
2612	  If unsure, say N.
2613
2614config TEST_SYSCTL
2615	tristate "sysctl test driver"
2616	depends on PROC_SYSCTL
2617	help
2618	  This builds the "test_sysctl" module. This driver enables to test the
2619	  proc sysctl interfaces available to drivers safely without affecting
2620	  production knobs which might alter system functionality.
2621
2622	  If unsure, say N.
2623
2624config BITFIELD_KUNIT
2625	tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2626	depends on KUNIT
2627	default KUNIT_ALL_TESTS
2628	help
2629	  Enable this option to test the bitfield functions at boot.
2630
2631	  KUnit tests run during boot and output the results to the debug log
2632	  in TAP format (http://testanything.org/). Only useful for kernel devs
2633	  running the KUnit test harness, and not intended for inclusion into a
2634	  production build.
2635
2636	  For more information on KUnit and unit tests in general please refer
2637	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2638
2639	  If unsure, say N.
2640
2641config CHECKSUM_KUNIT
2642	tristate "KUnit test checksum functions at runtime" if !KUNIT_ALL_TESTS
2643	depends on KUNIT
2644	default KUNIT_ALL_TESTS
2645	help
2646	  Enable this option to test the checksum functions at boot.
2647
2648	  KUnit tests run during boot and output the results to the debug log
2649	  in TAP format (http://testanything.org/). Only useful for kernel devs
2650	  running the KUnit test harness, and not intended for inclusion into a
2651	  production build.
2652
2653	  For more information on KUnit and unit tests in general please refer
2654	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2655
2656	  If unsure, say N.
2657
2658config UTIL_MACROS_KUNIT
2659	tristate "KUnit test util_macros.h functions at runtime" if !KUNIT_ALL_TESTS
2660	depends on KUNIT
2661	default KUNIT_ALL_TESTS
2662	help
2663	  Enable this option to test the util_macros.h function at boot.
2664
2665	  KUnit tests run during boot and output the results to the debug log
2666	  in TAP format (http://testanything.org/). Only useful for kernel devs
2667	  running the KUnit test harness, and not intended for inclusion into a
2668	  production build.
2669
2670	  For more information on KUnit and unit tests in general please refer
2671	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2672
2673	  If unsure, say N.
2674
2675config HASH_KUNIT_TEST
2676	tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2677	depends on KUNIT
2678	default KUNIT_ALL_TESTS
2679	help
2680	  Enable this option to test the kernel's string (<linux/stringhash.h>), and
2681	  integer (<linux/hash.h>) hash functions on boot.
2682
2683	  KUnit tests run during boot and output the results to the debug log
2684	  in TAP format (https://testanything.org/). Only useful for kernel devs
2685	  running the KUnit test harness, and not intended for inclusion into a
2686	  production build.
2687
2688	  For more information on KUnit and unit tests in general please refer
2689	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2690
2691	  This is intended to help people writing architecture-specific
2692	  optimized versions. If unsure, say N.
2693
2694config RESOURCE_KUNIT_TEST
2695	tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2696	depends on KUNIT
2697	default KUNIT_ALL_TESTS
2698	select GET_FREE_REGION
2699	help
2700	  This builds the resource API unit test.
2701	  Tests the logic of API provided by resource.c and ioport.h.
2702	  For more information on KUnit and unit tests in general please refer
2703	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2704
2705	  If unsure, say N.
2706
2707config SYSCTL_KUNIT_TEST
2708	tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2709	depends on KUNIT
2710	default KUNIT_ALL_TESTS
2711	help
2712	  This builds the proc sysctl unit test, which runs on boot.
2713	  Tests the API contract and implementation correctness of sysctl.
2714	  For more information on KUnit and unit tests in general please refer
2715	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2716
2717	  If unsure, say N.
2718
2719config KFIFO_KUNIT_TEST
2720	tristate "KUnit Test for the generic kernel FIFO implementation" if !KUNIT_ALL_TESTS
2721	depends on KUNIT
2722	default KUNIT_ALL_TESTS
2723	help
2724	  This builds the generic FIFO implementation KUnit test suite.
2725	  It tests that the API and basic functionality of the kfifo type
2726	  and associated macros.
2727
2728	  For more information on KUnit and unit tests in general please refer
2729	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2730
2731	  If unsure, say N.
2732
2733config LIST_KUNIT_TEST
2734	tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2735	depends on KUNIT
2736	default KUNIT_ALL_TESTS
2737	help
2738	  This builds the linked list KUnit test suite.
2739	  It tests that the API and basic functionality of the list_head type
2740	  and associated macros.
2741
2742	  KUnit tests run during boot and output the results to the debug log
2743	  in TAP format (https://testanything.org/). Only useful for kernel devs
2744	  running the KUnit test harness, and not intended for inclusion into a
2745	  production build.
2746
2747	  For more information on KUnit and unit tests in general please refer
2748	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2749
2750	  If unsure, say N.
2751
2752config HASHTABLE_KUNIT_TEST
2753	tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS
2754	depends on KUNIT
2755	default KUNIT_ALL_TESTS
2756	help
2757	  This builds the hashtable KUnit test suite.
2758	  It tests the basic functionality of the API defined in
2759	  include/linux/hashtable.h. For more information on KUnit and
2760	  unit tests in general please refer to the KUnit documentation
2761	  in Documentation/dev-tools/kunit/.
2762
2763	  If unsure, say N.
2764
2765config LINEAR_RANGES_TEST
2766	tristate "KUnit test for linear_ranges"
2767	depends on KUNIT
2768	select LINEAR_RANGES
2769	help
2770	  This builds the linear_ranges unit test, which runs on boot.
2771	  Tests the linear_ranges logic correctness.
2772	  For more information on KUnit and unit tests in general please refer
2773	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2774
2775	  If unsure, say N.
2776
2777config CMDLINE_KUNIT_TEST
2778	tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2779	depends on KUNIT
2780	default KUNIT_ALL_TESTS
2781	help
2782	  This builds the cmdline API unit test.
2783	  Tests the logic of API provided by cmdline.c.
2784	  For more information on KUnit and unit tests in general please refer
2785	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2786
2787	  If unsure, say N.
2788
2789config BITS_TEST
2790	tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2791	depends on KUNIT
2792	default KUNIT_ALL_TESTS
2793	help
2794	  This builds the bits unit test.
2795	  Tests the logic of macros defined in bits.h.
2796	  For more information on KUnit and unit tests in general please refer
2797	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2798
2799	  If unsure, say N.
2800
2801config SLUB_KUNIT_TEST
2802	tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2803	depends on SLUB_DEBUG && KUNIT
2804	default KUNIT_ALL_TESTS
2805	help
2806	  This builds SLUB allocator unit test.
2807	  Tests SLUB cache debugging functionality.
2808	  For more information on KUnit and unit tests in general please refer
2809	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2810
2811	  If unsure, say N.
2812
2813config RATIONAL_KUNIT_TEST
2814	tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2815	depends on KUNIT && RATIONAL
2816	default KUNIT_ALL_TESTS
2817	help
2818	  This builds the rational math unit test.
2819	  For more information on KUnit and unit tests in general please refer
2820	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2821
2822	  If unsure, say N.
2823
2824config MEMCPY_KUNIT_TEST
2825	tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2826	depends on KUNIT
2827	default KUNIT_ALL_TESTS
2828	help
2829	  Builds unit tests for memcpy(), memmove(), and memset() functions.
2830	  For more information on KUnit and unit tests in general please refer
2831	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2832
2833	  If unsure, say N.
2834
2835config IS_SIGNED_TYPE_KUNIT_TEST
2836	tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2837	depends on KUNIT
2838	default KUNIT_ALL_TESTS
2839	help
2840	  Builds unit tests for the is_signed_type() macro.
2841
2842	  For more information on KUnit and unit tests in general please refer
2843	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2844
2845	  If unsure, say N.
2846
2847config OVERFLOW_KUNIT_TEST
2848	tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2849	depends on KUNIT
2850	default KUNIT_ALL_TESTS
2851	help
2852	  Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2853	  related functions.
2854
2855	  For more information on KUnit and unit tests in general please refer
2856	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2857
2858	  If unsure, say N.
2859
2860config STACKINIT_KUNIT_TEST
2861	tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2862	depends on KUNIT
2863	default KUNIT_ALL_TESTS
2864	help
2865	  Test if the kernel is zero-initializing stack variables and
2866	  padding. Coverage is controlled by compiler flags,
2867	  CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2868	  CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2869	  or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2870
2871config FORTIFY_KUNIT_TEST
2872	tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2873	depends on KUNIT
2874	default KUNIT_ALL_TESTS
2875	help
2876	  Builds unit tests for checking internals of FORTIFY_SOURCE as used
2877	  by the str*() and mem*() family of functions. For testing runtime
2878	  traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2879
2880config LONGEST_SYM_KUNIT_TEST
2881	tristate "Test the longest symbol possible" if !KUNIT_ALL_TESTS
2882	depends on KUNIT && KPROBES
2883	default KUNIT_ALL_TESTS
2884	help
2885	  Tests the longest symbol possible
2886
2887	  If unsure, say N.
2888
2889config HW_BREAKPOINT_KUNIT_TEST
2890	bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2891	depends on HAVE_HW_BREAKPOINT
2892	depends on KUNIT=y
2893	default KUNIT_ALL_TESTS
2894	help
2895	  Tests for hw_breakpoint constraints accounting.
2896
2897	  If unsure, say N.
2898
2899config CRC_KUNIT_TEST
2900	tristate "KUnit tests for CRC functions" if !KUNIT_ALL_TESTS
2901	depends on KUNIT
2902	default KUNIT_ALL_TESTS
2903	select CRC7
2904	select CRC16
2905	select CRC_T10DIF
2906	select CRC32
2907	select CRC64
2908	help
2909	  Unit tests for the CRC library functions.
2910
2911	  This is intended to help people writing architecture-specific
2912	  optimized versions.  If unsure, say N.
2913
2914config CRC_BENCHMARK
2915	bool "Benchmark for the CRC functions"
2916	depends on CRC_KUNIT_TEST
2917	help
2918	  Include benchmarks in the KUnit test suite for the CRC functions.
2919
2920config SIPHASH_KUNIT_TEST
2921	tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2922	depends on KUNIT
2923	default KUNIT_ALL_TESTS
2924	help
2925	  Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2926	  functions on boot (or module load).
2927
2928	  This is intended to help people writing architecture-specific
2929	  optimized versions.  If unsure, say N.
2930
2931config USERCOPY_KUNIT_TEST
2932	tristate "KUnit Test for user/kernel boundary protections"
2933	depends on KUNIT
2934	default KUNIT_ALL_TESTS
2935	help
2936	  This builds the "usercopy_kunit" module that runs sanity checks
2937	  on the copy_to/from_user infrastructure, making sure basic
2938	  user/kernel boundary testing is working.
2939
2940config BLACKHOLE_DEV_KUNIT_TEST
2941	tristate "Test blackhole netdev functionality" if !KUNIT_ALL_TESTS
2942	depends on NET
2943	depends on KUNIT
2944	default KUNIT_ALL_TESTS
2945	help
2946	  This builds the "blackhole_dev_kunit" module that validates the
2947	  data path through this blackhole netdev.
2948
2949	  If unsure, say N.
2950
2951config TEST_UDELAY
2952	tristate "udelay test driver"
2953	help
2954	  This builds the "udelay_test" module that helps to make sure
2955	  that udelay() is working properly.
2956
2957	  If unsure, say N.
2958
2959config TEST_STATIC_KEYS
2960	tristate "Test static keys"
2961	depends on m
2962	help
2963	  Test the static key interfaces.
2964
2965	  If unsure, say N.
2966
2967config TEST_DYNAMIC_DEBUG
2968	tristate "Test DYNAMIC_DEBUG"
2969	depends on DYNAMIC_DEBUG
2970	help
2971	  This module registers a tracer callback to count enabled
2972	  pr_debugs in a 'do_debugging' function, then alters their
2973	  enablements, calls the function, and compares counts.
2974
2975	  If unsure, say N.
2976
2977config TEST_KMOD
2978	tristate "kmod stress tester"
2979	depends on m
2980	depends on NETDEVICES && NET_CORE && INET # for TUN
2981	depends on BLOCK
2982	depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2983	select TEST_LKM
2984	select XFS_FS
2985	select TUN
2986	select BTRFS_FS
2987	help
2988	  Test the kernel's module loading mechanism: kmod. kmod implements
2989	  support to load modules using the Linux kernel's usermode helper.
2990	  This test provides a series of tests against kmod.
2991
2992	  Although technically you can either build test_kmod as a module or
2993	  into the kernel we disallow building it into the kernel since
2994	  it stress tests request_module() and this will very likely cause
2995	  some issues by taking over precious threads available from other
2996	  module load requests, ultimately this could be fatal.
2997
2998	  To run tests run:
2999
3000	  tools/testing/selftests/kmod/kmod.sh --help
3001
3002	  If unsure, say N.
3003
3004config TEST_RUNTIME
3005	bool
3006
3007config TEST_RUNTIME_MODULE
3008	bool
3009
3010config TEST_KALLSYMS
3011	tristate "module kallsyms find_symbol() test"
3012	depends on m
3013	select TEST_RUNTIME
3014	select TEST_RUNTIME_MODULE
3015	select TEST_KALLSYMS_A
3016	select TEST_KALLSYMS_B
3017	select TEST_KALLSYMS_C
3018	select TEST_KALLSYMS_D
3019	help
3020	  This allows us to stress test find_symbol() through the kallsyms
3021	  used to place symbols on the kernel ELF kallsyms and modules kallsyms
3022	  where we place kernel symbols such as exported symbols.
3023
3024	  We have four test modules:
3025
3026	  A: has KALLSYSMS_NUMSYMS exported symbols
3027	  B: uses one of A's symbols
3028	  C: adds KALLSYMS_SCALE_FACTOR * KALLSYSMS_NUMSYMS exported
3029	  D: adds 2 * the symbols than C
3030
3031	  We stress test find_symbol() through two means:
3032
3033	  1) Upon load of B it will trigger simplify_symbols() to look for the
3034	  one symbol it uses from the module A with tons of symbols. This is an
3035	  indirect way for us to have B call resolve_symbol_wait() upon module
3036	  load. This will eventually call find_symbol() which will eventually
3037	  try to find the symbols used with find_exported_symbol_in_section().
3038	  find_exported_symbol_in_section() uses bsearch() so a binary search
3039	  for each symbol. Binary search will at worst be O(log(n)) so the
3040	  larger TEST_MODULE_KALLSYSMS the worse the search.
3041
3042	  2) The selftests should load C first, before B. Upon B's load towards
3043	  the end right before we call module B's init routine we get
3044	  complete_formation() called on the module. That will first check
3045	  for duplicate symbols with the call to verify_exported_symbols().
3046	  That is when we'll force iteration on module C's insane symbol list.
3047	  Since it has 10 * KALLSYMS_NUMSYMS it means we can first test
3048	  just loading B without C. The amount of time it takes to load C Vs
3049	  B can give us an idea of the impact growth of the symbol space and
3050	  give us projection. Module A only uses one symbol from B so to allow
3051	  this scaling in module C to be proportional, if it used more symbols
3052	  then the first test would be doing more and increasing just the
3053	  search space would be slightly different. The last module, module D
3054	  will just increase the search space by twice the number of symbols in
3055	  C so to allow for full projects.
3056
3057	  tools/testing/selftests/module/find_symbol.sh
3058
3059	  The current defaults will incur a build delay of about 7 minutes
3060	  on an x86_64 with only 8 cores. Enable this only if you want to
3061	  stress test find_symbol() with thousands of symbols. At the same
3062	  time this is also useful to test building modules with thousands of
3063	  symbols, and if BTF is enabled this also stress tests adding BTF
3064	  information for each module. Currently enabling many more symbols
3065	  will segfault the build system.
3066
3067	  If unsure, say N.
3068
3069if TEST_KALLSYMS
3070
3071config TEST_KALLSYMS_A
3072	tristate
3073	depends on m
3074
3075config TEST_KALLSYMS_B
3076	tristate
3077	depends on m
3078
3079config TEST_KALLSYMS_C
3080	tristate
3081	depends on m
3082
3083config TEST_KALLSYMS_D
3084	tristate
3085	depends on m
3086
3087choice
3088	prompt "Kallsym test range"
3089	default TEST_KALLSYMS_LARGE
3090	help
3091	  Selecting something other than "Fast" will enable tests which slow
3092	  down the build and may crash your build.
3093
3094config TEST_KALLSYMS_FAST
3095	bool "Fast builds"
3096	help
3097	  You won't really be testing kallsysms, so this just helps fast builds
3098	  when allmodconfig is used..
3099
3100config TEST_KALLSYMS_LARGE
3101	bool "Enable testing kallsyms with large exports"
3102	help
3103	  This will enable larger number of symbols. This will slow down
3104	  your build considerably.
3105
3106config TEST_KALLSYMS_MAX
3107	bool "Known kallsysms limits"
3108	help
3109	  This will enable exports to the point we know we'll start crashing
3110	  builds.
3111
3112endchoice
3113
3114config TEST_KALLSYMS_NUMSYMS
3115	int "test kallsyms number of symbols"
3116	range 2 10000
3117	default 2 if TEST_KALLSYMS_FAST
3118	default 100 if TEST_KALLSYMS_LARGE
3119	default 10000 if TEST_KALLSYMS_MAX
3120	help
3121	  The number of symbols to create on TEST_KALLSYMS_A, only one of which
3122	  module TEST_KALLSYMS_B will use. This also will be used
3123	  for how many symbols TEST_KALLSYMS_C will have, scaled up by
3124	  TEST_KALLSYMS_SCALE_FACTOR. Note that setting this to 10,000 will
3125	  trigger a segfault today, don't use anything close to it unless
3126	  you are aware that this should not be used for automated build tests.
3127
3128config TEST_KALLSYMS_SCALE_FACTOR
3129	int "test kallsyms scale factor"
3130	default 8
3131	help
3132	  How many more unusued symbols will TEST_KALLSYSMS_C have than
3133	  TEST_KALLSYMS_A. If 8, then module C will have 8 * syms
3134	  than module A. Then TEST_KALLSYMS_D will have double the amount
3135	  of symbols than C so to allow projections.
3136
3137endif # TEST_KALLSYMS
3138
3139config TEST_DEBUG_VIRTUAL
3140	tristate "Test CONFIG_DEBUG_VIRTUAL feature"
3141	depends on DEBUG_VIRTUAL
3142	help
3143	  Test the kernel's ability to detect incorrect calls to
3144	  virt_to_phys() done against the non-linear part of the
3145	  kernel's virtual address map.
3146
3147	  If unsure, say N.
3148
3149config TEST_MEMCAT_P
3150	tristate "Test memcat_p() helper function"
3151	help
3152	  Test the memcat_p() helper for correctly merging two
3153	  pointer arrays together.
3154
3155	  If unsure, say N.
3156
3157config TEST_OBJAGG
3158	tristate "Perform selftest on object aggreration manager"
3159	default n
3160	depends on OBJAGG
3161	help
3162	  Enable this option to test object aggregation manager on boot
3163	  (or module load).
3164
3165config TEST_MEMINIT
3166	tristate "Test heap/page initialization"
3167	help
3168	  Test if the kernel is zero-initializing heap and page allocations.
3169	  This can be useful to test init_on_alloc and init_on_free features.
3170
3171	  If unsure, say N.
3172
3173config TEST_HMM
3174	tristate "Test HMM (Heterogeneous Memory Management)"
3175	depends on TRANSPARENT_HUGEPAGE
3176	depends on DEVICE_PRIVATE
3177	select HMM_MIRROR
3178	select MMU_NOTIFIER
3179	help
3180	  This is a pseudo device driver solely for testing HMM.
3181	  Say M here if you want to build the HMM test module.
3182	  Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
3183
3184	  If unsure, say N.
3185
3186config TEST_FREE_PAGES
3187	tristate "Test freeing pages"
3188	help
3189	  Test that a memory leak does not occur due to a race between
3190	  freeing a block of pages and a speculative page reference.
3191	  Loading this module is safe if your kernel has the bug fixed.
3192	  If the bug is not fixed, it will leak gigabytes of memory and
3193	  probably OOM your system.
3194
3195config TEST_FPU
3196	tristate "Test floating point operations in kernel space"
3197	depends on ARCH_HAS_KERNEL_FPU_SUPPORT && !KCOV_INSTRUMENT_ALL
3198	help
3199	  Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
3200	  which will trigger a sequence of floating point operations. This is used
3201	  for self-testing floating point control register setting in
3202	  kernel_fpu_begin().
3203
3204	  If unsure, say N.
3205
3206config TEST_CLOCKSOURCE_WATCHDOG
3207	tristate "Test clocksource watchdog in kernel space"
3208	depends on CLOCKSOURCE_WATCHDOG
3209	help
3210	  Enable this option to create a kernel module that will trigger
3211	  a test of the clocksource watchdog.  This module may be loaded
3212	  via modprobe or insmod in which case it will run upon being
3213	  loaded, or it may be built in, in which case it will run
3214	  shortly after boot.
3215
3216	  If unsure, say N.
3217
3218config TEST_OBJPOOL
3219	tristate "Test module for correctness and stress of objpool"
3220	default n
3221	depends on m && DEBUG_KERNEL
3222	help
3223	  This builds the "test_objpool" module that should be used for
3224	  correctness verification and concurrent testings of objects
3225	  allocation and reclamation.
3226
3227	  If unsure, say N.
3228
3229config INT_POW_KUNIT_TEST
3230	tristate "Integer exponentiation (int_pow) test" if !KUNIT_ALL_TESTS
3231	depends on KUNIT
3232	default KUNIT_ALL_TESTS
3233	help
3234	  This option enables the KUnit test suite for the int_pow function,
3235	  which performs integer exponentiation. The test suite is designed to
3236	  verify that the implementation of int_pow correctly computes the power
3237	  of a given base raised to a given exponent.
3238
3239	  Enabling this option will include tests that check various scenarios
3240	  and edge cases to ensure the accuracy and reliability of the exponentiation
3241	  function.
3242
3243	  If unsure, say N
3244
3245config INT_SQRT_KUNIT_TEST
3246	tristate "Integer square root test" if !KUNIT_ALL_TESTS
3247	depends on KUNIT
3248	default KUNIT_ALL_TESTS
3249	help
3250	  This option enables the KUnit test suite for the int_sqrt() function,
3251	  which performs square root calculation. The test suite checks
3252	  various scenarios, including edge cases, to ensure correctness.
3253
3254	  Enabling this option will include tests that check various scenarios
3255	  and edge cases to ensure the accuracy and reliability of the square root
3256	  function.
3257
3258	  If unsure, say N
3259
3260config INT_LOG_KUNIT_TEST
3261        tristate "Integer log (int_log) test" if !KUNIT_ALL_TESTS
3262        depends on KUNIT
3263        default KUNIT_ALL_TESTS
3264        help
3265          This option enables the KUnit test suite for the int_log library, which
3266          provides two functions to compute the integer logarithm in base 2 and
3267          base 10, called respectively as intlog2 and intlog10.
3268
3269          If unsure, say N
3270
3271config GCD_KUNIT_TEST
3272	tristate "Greatest common divisor test" if !KUNIT_ALL_TESTS
3273	depends on KUNIT
3274	default KUNIT_ALL_TESTS
3275	help
3276	  This option enables the KUnit test suite for the gcd() function,
3277	  which computes the greatest common divisor of two numbers.
3278
3279	  This test suite verifies the correctness of gcd() across various
3280	  scenarios, including edge cases.
3281
3282	  If unsure, say N
3283
3284config PRIME_NUMBERS_KUNIT_TEST
3285	tristate "Prime number generator test" if !KUNIT_ALL_TESTS
3286	depends on KUNIT
3287	select PRIME_NUMBERS
3288	default KUNIT_ALL_TESTS
3289	help
3290	  This option enables the KUnit test suite for the {is,next}_prime_number
3291	  functions.
3292
3293	  Enabling this option will include tests that compare the prime number
3294	  generator functions against a brute force implementation.
3295
3296	  If unsure, say N
3297
3298endif # RUNTIME_TESTING_MENU
3299
3300config ARCH_USE_MEMTEST
3301	bool
3302	help
3303	  An architecture should select this when it uses early_memtest()
3304	  during boot process.
3305
3306config MEMTEST
3307	bool "Memtest"
3308	depends on ARCH_USE_MEMTEST
3309	help
3310	  This option adds a kernel parameter 'memtest', which allows memtest
3311	  to be set and executed.
3312	        memtest=0, mean disabled; -- default
3313	        memtest=1, mean do 1 test pattern;
3314	        ...
3315	        memtest=17, mean do 17 test patterns.
3316	  If you are unsure how to answer this question, answer N.
3317
3318
3319
3320config HYPERV_TESTING
3321	bool "Microsoft Hyper-V driver testing"
3322	default n
3323	depends on HYPERV && DEBUG_FS
3324	help
3325	  Select this option to enable Hyper-V vmbus testing.
3326
3327endmenu # "Kernel Testing and Coverage"
3328
3329menu "Rust hacking"
3330
3331config RUST_DEBUG_ASSERTIONS
3332	bool "Debug assertions"
3333	depends on RUST
3334	help
3335	  Enables rustc's `-Cdebug-assertions` codegen option.
3336
3337	  This flag lets you turn `cfg(debug_assertions)` conditional
3338	  compilation on or off. This can be used to enable extra debugging
3339	  code in development but not in production. For example, it controls
3340	  the behavior of the standard library's `debug_assert!` macro.
3341
3342	  Note that this will apply to all Rust code, including `core`.
3343
3344	  If unsure, say N.
3345
3346config RUST_OVERFLOW_CHECKS
3347	bool "Overflow checks"
3348	default y
3349	depends on RUST
3350	help
3351	  Enables rustc's `-Coverflow-checks` codegen option.
3352
3353	  This flag allows you to control the behavior of runtime integer
3354	  overflow. When overflow-checks are enabled, a Rust panic will occur
3355	  on overflow.
3356
3357	  Note that this will apply to all Rust code, including `core`.
3358
3359	  If unsure, say Y.
3360
3361config RUST_BUILD_ASSERT_ALLOW
3362	bool "Allow unoptimized build-time assertions"
3363	depends on RUST
3364	help
3365	  Controls how `build_error!` and `build_assert!` are handled during the build.
3366
3367	  If calls to them exist in the binary, it may indicate a violated invariant
3368	  or that the optimizer failed to verify the invariant during compilation.
3369
3370	  This should not happen, thus by default the build is aborted. However,
3371	  as an escape hatch, you can choose Y here to ignore them during build
3372	  and let the check be carried at runtime (with `panic!` being called if
3373	  the check fails).
3374
3375	  If unsure, say N.
3376
3377config RUST_KERNEL_DOCTESTS
3378	bool "Doctests for the `kernel` crate" if !KUNIT_ALL_TESTS
3379	depends on RUST && KUNIT=y
3380	default KUNIT_ALL_TESTS
3381	help
3382	  This builds the documentation tests of the `kernel` crate
3383	  as KUnit tests.
3384
3385	  For more information on KUnit and unit tests in general,
3386	  please refer to the KUnit documentation in Documentation/dev-tools/kunit/.
3387
3388	  If unsure, say N.
3389
3390endmenu # "Rust"
3391
3392endmenu # Kernel hacking
3393