xref: /linux/lib/Kconfig.debug (revision f4d2ef48250ad057e4f00087967b5ff366da9f39)
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 debian/rules 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 or DPKG_DEB_COMPRESSOR_TYPE to
343	  "none" which would be even 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	help
477	  This option will install uapi headers (headers exported to user-space)
478	  into the usr/include directory for use during the kernel build.
479	  This is unneeded for building the kernel itself, but needed for some
480	  user-space program samples. It is also needed by some features such
481	  as uapi header sanity checks.
482
483config DEBUG_SECTION_MISMATCH
484	bool "Enable full Section mismatch analysis"
485	depends on CC_IS_GCC
486	help
487	  The section mismatch analysis checks if there are illegal
488	  references from one section to another section.
489	  During linktime or runtime, some sections are dropped;
490	  any use of code/data previously in these sections would
491	  most likely result in an oops.
492	  In the code, functions and variables are annotated with
493	  __init,, etc. (see the full list in include/linux/init.h),
494	  which results in the code/data being placed in specific sections.
495	  The section mismatch analysis is always performed after a full
496	  kernel build, and enabling this option causes the following
497	  additional step to occur:
498	  - Add the option -fno-inline-functions-called-once to gcc commands.
499	    When inlining a function annotated with __init in a non-init
500	    function, we would lose the section information and thus
501	    the analysis would not catch the illegal reference.
502	    This option tells gcc to inline less (but it does result in
503	    a larger kernel).
504
505config SECTION_MISMATCH_WARN_ONLY
506	bool "Make section mismatch errors non-fatal"
507	default y
508	help
509	  If you say N here, the build process will fail if there are any
510	  section mismatch, instead of just throwing warnings.
511
512	  If unsure, say Y.
513
514config DEBUG_FORCE_FUNCTION_ALIGN_64B
515	bool "Force all function address 64B aligned"
516	depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC || RISCV || S390)
517	select FUNCTION_ALIGNMENT_64B
518	help
519	  There are cases that a commit from one domain changes the function
520	  address alignment of other domains, and cause magic performance
521	  bump (regression or improvement). Enable this option will help to
522	  verify if the bump is caused by function alignment changes, while
523	  it will slightly increase the kernel size and affect icache usage.
524
525	  It is mainly for debug and performance tuning use.
526
527#
528# Select this config option from the architecture Kconfig, if it
529# is preferred to always offer frame pointers as a config
530# option on the architecture (regardless of KERNEL_DEBUG):
531#
532config ARCH_WANT_FRAME_POINTERS
533	bool
534
535config FRAME_POINTER
536	bool "Compile the kernel with frame pointers"
537	depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
538	default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
539	help
540	  If you say Y here the resulting kernel image will be slightly
541	  larger and slower, but it gives very useful debugging information
542	  in case of kernel bugs. (precise oopses/stacktraces/warnings)
543
544config OBJTOOL
545	bool
546
547config OBJTOOL_WERROR
548	bool "Upgrade objtool warnings to errors"
549	depends on OBJTOOL && !COMPILE_TEST
550	help
551	  Fail the build on objtool warnings.
552
553	  Objtool warnings can indicate kernel instability, including boot
554	  failures.  This option is highly recommended.
555
556	  If unsure, say Y.
557
558config STACK_VALIDATION
559	bool "Compile-time stack metadata validation"
560	depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
561	select OBJTOOL
562	default n
563	help
564	  Validate frame pointer rules at compile-time.  This helps ensure that
565	  runtime stack traces are more reliable.
566
567	  For more information, see
568	  tools/objtool/Documentation/objtool.txt.
569
570config NOINSTR_VALIDATION
571	bool
572	depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
573	select OBJTOOL
574	default y
575
576config VMLINUX_MAP
577	bool "Generate vmlinux.map file when linking"
578	depends on EXPERT
579	help
580	  Selecting this option will pass "-Map=vmlinux.map" to ld
581	  when linking vmlinux. That file can be useful for verifying
582	  and debugging magic section games, and for seeing which
583	  pieces of code get eliminated with
584	  CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
585
586config BUILTIN_MODULE_RANGES
587	bool "Generate address range information for builtin modules"
588	depends on !LTO
589	depends on VMLINUX_MAP
590	help
591	 When modules are built into the kernel, there will be no module name
592	 associated with its symbols in /proc/kallsyms.  Tracers may want to
593	 identify symbols by module name and symbol name regardless of whether
594	 the module is configured as loadable or not.
595
596	 This option generates modules.builtin.ranges in the build tree with
597	 offset ranges (per ELF section) for the module(s) they belong to.
598	 It also records an anchor symbol to determine the load address of the
599	 section.
600
601config DEBUG_FORCE_WEAK_PER_CPU
602	bool "Force weak per-cpu definitions"
603	depends on DEBUG_KERNEL
604	help
605	  s390 and alpha require percpu variables in modules to be
606	  defined weak to work around addressing range issue which
607	  puts the following two restrictions on percpu variable
608	  definitions.
609
610	  1. percpu symbols must be unique whether static or not
611	  2. percpu variables can't be defined inside a function
612
613	  To ensure that generic code follows the above rules, this
614	  option forces all percpu variables to be defined as weak.
615
616endmenu # "Compiler options"
617
618menu "Generic Kernel Debugging Instruments"
619
620config MAGIC_SYSRQ
621	bool "Magic SysRq key"
622	depends on !UML
623	help
624	  If you say Y here, you will have some control over the system even
625	  if the system crashes for example during kernel debugging (e.g., you
626	  will be able to flush the buffer cache to disk, reboot the system
627	  immediately or dump some status information). This is accomplished
628	  by pressing various keys while holding SysRq (Alt+PrintScreen). It
629	  also works on a serial console (on PC hardware at least), if you
630	  send a BREAK and then within 5 seconds a command keypress. The
631	  keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
632	  Don't say Y unless you really know what this hack does.
633
634config MAGIC_SYSRQ_DEFAULT_ENABLE
635	hex "Enable magic SysRq key functions by default"
636	depends on MAGIC_SYSRQ
637	default 0x1
638	help
639	  Specifies which SysRq key functions are enabled by default.
640	  This may be set to 1 or 0 to enable or disable them all, or
641	  to a bitmask as described in Documentation/admin-guide/sysrq.rst.
642
643config MAGIC_SYSRQ_SERIAL
644	bool "Enable magic SysRq key over serial"
645	depends on MAGIC_SYSRQ
646	default y
647	help
648	  Many embedded boards have a disconnected TTL level serial which can
649	  generate some garbage that can lead to spurious false sysrq detects.
650	  This option allows you to decide whether you want to enable the
651	  magic SysRq key.
652
653config MAGIC_SYSRQ_SERIAL_SEQUENCE
654	string "Char sequence that enables magic SysRq over serial"
655	depends on MAGIC_SYSRQ_SERIAL
656	default ""
657	help
658	  Specifies a sequence of characters that can follow BREAK to enable
659	  SysRq on a serial console.
660
661	  If unsure, leave an empty string and the option will not be enabled.
662
663config DEBUG_FS
664	bool "Debug Filesystem"
665	help
666	  debugfs is a virtual file system that kernel developers use to put
667	  debugging files into.  Enable this option to be able to read and
668	  write to these files.
669
670	  For detailed documentation on the debugfs API, see
671	  Documentation/filesystems/.
672
673	  If unsure, say N.
674
675choice
676	prompt "Debugfs default access"
677	depends on DEBUG_FS
678	default DEBUG_FS_ALLOW_ALL
679	help
680	  This selects the default access restrictions for debugfs.
681	  It can be overridden with kernel command line option
682	  debugfs=[on,no-mount,off]. The restrictions apply for API access
683	  and filesystem registration.
684
685config DEBUG_FS_ALLOW_ALL
686	bool "Access normal"
687	help
688	  No restrictions apply. Both API and filesystem registration
689	  is on. This is the normal default operation.
690
691config DEBUG_FS_DISALLOW_MOUNT
692	bool "Do not register debugfs as filesystem"
693	help
694	  The API is open but filesystem is not loaded. Clients can still do
695	  their work and read with debug tools that do not need
696	  debugfs filesystem.
697
698config DEBUG_FS_ALLOW_NONE
699	bool "No access"
700	help
701	  Access is off. Clients get -PERM when trying to create nodes in
702	  debugfs tree and debugfs is not registered as a filesystem.
703	  Client can then back-off or continue without debugfs access.
704
705endchoice
706
707source "lib/Kconfig.kgdb"
708source "lib/Kconfig.ubsan"
709source "lib/Kconfig.kcsan"
710
711endmenu
712
713menu "Networking Debugging"
714
715source "net/Kconfig.debug"
716
717endmenu # "Networking Debugging"
718
719menu "Memory Debugging"
720
721source "mm/Kconfig.debug"
722
723config DEBUG_OBJECTS
724	bool "Debug object operations"
725	depends on DEBUG_KERNEL
726	help
727	  If you say Y here, additional code will be inserted into the
728	  kernel to track the life time of various objects and validate
729	  the operations on those objects.
730
731config DEBUG_OBJECTS_SELFTEST
732	bool "Debug objects selftest"
733	depends on DEBUG_OBJECTS
734	help
735	  This enables the selftest of the object debug code.
736
737config DEBUG_OBJECTS_FREE
738	bool "Debug objects in freed memory"
739	depends on DEBUG_OBJECTS
740	help
741	  This enables checks whether a k/v free operation frees an area
742	  which contains an object which has not been deactivated
743	  properly. This can make kmalloc/kfree-intensive workloads
744	  much slower.
745
746config DEBUG_OBJECTS_TIMERS
747	bool "Debug timer objects"
748	depends on DEBUG_OBJECTS
749	help
750	  If you say Y here, additional code will be inserted into the
751	  timer routines to track the life time of timer objects and
752	  validate the timer operations.
753
754config DEBUG_OBJECTS_WORK
755	bool "Debug work objects"
756	depends on DEBUG_OBJECTS
757	help
758	  If you say Y here, additional code will be inserted into the
759	  work queue routines to track the life time of work objects and
760	  validate the work operations.
761
762config DEBUG_OBJECTS_RCU_HEAD
763	bool "Debug RCU callbacks objects"
764	depends on DEBUG_OBJECTS
765	help
766	  Enable this to turn on debugging of RCU list heads (call_rcu() usage).
767
768config DEBUG_OBJECTS_PERCPU_COUNTER
769	bool "Debug percpu counter objects"
770	depends on DEBUG_OBJECTS
771	help
772	  If you say Y here, additional code will be inserted into the
773	  percpu counter routines to track the life time of percpu counter
774	  objects and validate the percpu counter operations.
775
776config DEBUG_OBJECTS_ENABLE_DEFAULT
777	int "debug_objects bootup default value (0-1)"
778	range 0 1
779	default "1"
780	depends on DEBUG_OBJECTS
781	help
782	  Debug objects boot parameter default value
783
784config SHRINKER_DEBUG
785	bool "Enable shrinker debugging support"
786	depends on DEBUG_FS
787	help
788	  Say Y to enable the shrinker debugfs interface which provides
789	  visibility into the kernel memory shrinkers subsystem.
790	  Disable it to avoid an extra memory footprint.
791
792config DEBUG_STACK_USAGE
793	bool "Stack utilization instrumentation"
794	depends on DEBUG_KERNEL
795	help
796	  Enables the display of the minimum amount of free stack which each
797	  task has ever had available in the sysrq-T and sysrq-P debug output.
798	  Also emits a message to dmesg when a process exits if that process
799	  used more stack space than previously exiting processes.
800
801	  This option will slow down process creation somewhat.
802
803config SCHED_STACK_END_CHECK
804	bool "Detect stack corruption on calls to schedule()"
805	depends on DEBUG_KERNEL
806	default n
807	help
808	  This option checks for a stack overrun on calls to schedule().
809	  If the stack end location is found to be over written always panic as
810	  the content of the corrupted region can no longer be trusted.
811	  This is to ensure no erroneous behaviour occurs which could result in
812	  data corruption or a sporadic crash at a later stage once the region
813	  is examined. The runtime overhead introduced is minimal.
814
815config ARCH_HAS_DEBUG_VM_PGTABLE
816	bool
817	help
818	  An architecture should select this when it can successfully
819	  build and run DEBUG_VM_PGTABLE.
820
821config DEBUG_VFS
822	bool "Debug VFS"
823	depends on DEBUG_KERNEL
824	help
825	  Enable this to turn on extended checks in the VFS layer that may impact
826	  performance.
827
828	  If unsure, say N.
829
830config DEBUG_VM_IRQSOFF
831	def_bool DEBUG_VM && !PREEMPT_RT
832
833config DEBUG_VM
834	bool "Debug VM"
835	depends on DEBUG_KERNEL
836	help
837	  Enable this to turn on extended checks in the virtual-memory system
838	  that may impact performance.
839
840	  If unsure, say N.
841
842config DEBUG_VM_SHOOT_LAZIES
843	bool "Debug MMU_LAZY_TLB_SHOOTDOWN implementation"
844	depends on DEBUG_VM
845	depends on MMU_LAZY_TLB_SHOOTDOWN
846	help
847	  Enable additional IPIs that ensure lazy tlb mm references are removed
848	  before the mm is freed.
849
850	  If unsure, say N.
851
852config DEBUG_VM_MAPLE_TREE
853	bool "Debug VM maple trees"
854	depends on DEBUG_VM
855	select DEBUG_MAPLE_TREE
856	help
857	  Enable VM maple tree debugging information and extra validations.
858
859	  If unsure, say N.
860
861config DEBUG_VM_RB
862	bool "Debug VM red-black trees"
863	depends on DEBUG_VM
864	help
865	  Enable VM red-black tree debugging information and extra validations.
866
867	  If unsure, say N.
868
869config DEBUG_VM_PGFLAGS
870	bool "Debug page-flags operations"
871	depends on DEBUG_VM
872	help
873	  Enables extra validation on page flags operations.
874
875	  If unsure, say N.
876
877config DEBUG_VM_PGTABLE
878	bool "Debug arch page table for semantics compliance"
879	depends on MMU
880	depends on ARCH_HAS_DEBUG_VM_PGTABLE
881	default y if DEBUG_VM
882	help
883	  This option provides a debug method which can be used to test
884	  architecture page table helper functions on various platforms in
885	  verifying if they comply with expected generic MM semantics. This
886	  will help architecture code in making sure that any changes or
887	  new additions of these helpers still conform to expected
888	  semantics of the generic MM. Platforms will have to opt in for
889	  this through ARCH_HAS_DEBUG_VM_PGTABLE.
890
891	  If unsure, say N.
892
893config ARCH_HAS_DEBUG_VIRTUAL
894	bool
895
896config DEBUG_VIRTUAL
897	bool "Debug VM translations"
898	depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
899	help
900	  Enable some costly sanity checks in virtual to page code. This can
901	  catch mistakes with virt_to_page() and friends.
902
903	  If unsure, say N.
904
905config DEBUG_NOMMU_REGIONS
906	bool "Debug the global anon/private NOMMU mapping region tree"
907	depends on DEBUG_KERNEL && !MMU
908	help
909	  This option causes the global tree of anonymous and private mapping
910	  regions to be regularly checked for invalid topology.
911
912config DEBUG_MEMORY_INIT
913	bool "Debug memory initialisation" if EXPERT
914	default !EXPERT
915	help
916	  Enable this for additional checks during memory initialisation.
917	  The sanity checks verify aspects of the VM such as the memory model
918	  and other information provided by the architecture. Verbose
919	  information will be printed at KERN_DEBUG loglevel depending
920	  on the mminit_loglevel= command-line option.
921
922	  If unsure, say Y
923
924config MEMORY_NOTIFIER_ERROR_INJECT
925	tristate "Memory hotplug notifier error injection module"
926	depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
927	help
928	  This option provides the ability to inject artificial errors to
929	  memory hotplug notifier chain callbacks.  It is controlled through
930	  debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
931
932	  If the notifier call chain should be failed with some events
933	  notified, write the error code to "actions/<notifier event>/error".
934
935	  Example: Inject memory hotplug offline error (-12 == -ENOMEM)
936
937	  # cd /sys/kernel/debug/notifier-error-inject/memory
938	  # echo -12 > actions/MEM_GOING_OFFLINE/error
939	  # echo offline > /sys/devices/system/memory/memoryXXX/state
940	  bash: echo: write error: Cannot allocate memory
941
942	  To compile this code as a module, choose M here: the module will
943	  be called memory-notifier-error-inject.
944
945	  If unsure, say N.
946
947config DEBUG_PER_CPU_MAPS
948	bool "Debug access to per_cpu maps"
949	depends on DEBUG_KERNEL
950	depends on SMP
951	help
952	  Say Y to verify that the per_cpu map being accessed has
953	  been set up. This adds a fair amount of code to kernel memory
954	  and decreases performance.
955
956	  Say N if unsure.
957
958config DEBUG_KMAP_LOCAL
959	bool "Debug kmap_local temporary mappings"
960	depends on DEBUG_KERNEL && KMAP_LOCAL
961	help
962	  This option enables additional error checking for the kmap_local
963	  infrastructure.  Disable for production use.
964
965config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
966	bool
967
968config DEBUG_KMAP_LOCAL_FORCE_MAP
969	bool "Enforce kmap_local temporary mappings"
970	depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
971	select KMAP_LOCAL
972	select DEBUG_KMAP_LOCAL
973	help
974	  This option enforces temporary mappings through the kmap_local
975	  mechanism for non-highmem pages and on non-highmem systems.
976	  Disable this for production systems!
977
978config DEBUG_HIGHMEM
979	bool "Highmem debugging"
980	depends on DEBUG_KERNEL && HIGHMEM
981	select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
982	select DEBUG_KMAP_LOCAL
983	help
984	  This option enables additional error checking for high memory
985	  systems.  Disable for production systems.
986
987config HAVE_DEBUG_STACKOVERFLOW
988	bool
989
990config DEBUG_STACKOVERFLOW
991	bool "Check for stack overflows"
992	depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
993	help
994	  Say Y here if you want to check for overflows of kernel, IRQ
995	  and exception stacks (if your architecture uses them). This
996	  option will show detailed messages if free stack space drops
997	  below a certain limit.
998
999	  These kinds of bugs usually occur when call-chains in the
1000	  kernel get too deep, especially when interrupts are
1001	  involved.
1002
1003	  Use this in cases where you see apparently random memory
1004	  corruption, especially if it appears in 'struct thread_info'
1005
1006	  If in doubt, say "N".
1007
1008config CODE_TAGGING
1009	bool
1010	select KALLSYMS
1011
1012config MEM_ALLOC_PROFILING
1013	bool "Enable memory allocation profiling"
1014	default n
1015	depends on MMU
1016	depends on PROC_FS
1017	depends on !DEBUG_FORCE_WEAK_PER_CPU
1018	select CODE_TAGGING
1019	select PAGE_EXTENSION
1020	select SLAB_OBJ_EXT
1021	help
1022	  Track allocation source code and record total allocation size
1023	  initiated at that code location. The mechanism can be used to track
1024	  memory leaks with a low performance and memory impact.
1025
1026config MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
1027	bool "Enable memory allocation profiling by default"
1028	default y
1029	depends on MEM_ALLOC_PROFILING
1030
1031config MEM_ALLOC_PROFILING_DEBUG
1032	bool "Memory allocation profiler debugging"
1033	default n
1034	depends on MEM_ALLOC_PROFILING
1035	select MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
1036	help
1037	  Adds warnings with helpful error messages for memory allocation
1038	  profiling.
1039
1040source "lib/Kconfig.kasan"
1041source "lib/Kconfig.kfence"
1042source "lib/Kconfig.kmsan"
1043
1044endmenu # "Memory Debugging"
1045
1046config DEBUG_SHIRQ
1047	bool "Debug shared IRQ handlers"
1048	depends on DEBUG_KERNEL
1049	help
1050	  Enable this to generate a spurious interrupt just before a shared
1051	  interrupt handler is deregistered (generating one when registering
1052	  is currently disabled). Drivers need to handle this correctly. Some
1053	  don't and need to be caught.
1054
1055menu "Debug Oops, Lockups and Hangs"
1056
1057config PANIC_ON_OOPS
1058	bool "Panic on Oops"
1059	help
1060	  Say Y here to enable the kernel to panic when it oopses. This
1061	  has the same effect as setting oops=panic on the kernel command
1062	  line.
1063
1064	  This feature is useful to ensure that the kernel does not do
1065	  anything erroneous after an oops which could result in data
1066	  corruption or other issues.
1067
1068	  Say N if unsure.
1069
1070config PANIC_ON_OOPS_VALUE
1071	int
1072	range 0 1
1073	default 0 if !PANIC_ON_OOPS
1074	default 1 if PANIC_ON_OOPS
1075
1076config PANIC_TIMEOUT
1077	int "panic timeout"
1078	default 0
1079	help
1080	  Set the timeout value (in seconds) until a reboot occurs when
1081	  the kernel panics. If n = 0, then we wait forever. A timeout
1082	  value n > 0 will wait n seconds before rebooting, while a timeout
1083	  value n < 0 will reboot immediately. This setting can be overridden
1084	  with the kernel command line option panic=, and from userspace via
1085	  /proc/sys/kernel/panic.
1086
1087config LOCKUP_DETECTOR
1088	bool
1089
1090config SOFTLOCKUP_DETECTOR
1091	bool "Detect Soft Lockups"
1092	depends on DEBUG_KERNEL && !S390
1093	select LOCKUP_DETECTOR
1094	help
1095	  Say Y here to enable the kernel to act as a watchdog to detect
1096	  soft lockups.
1097
1098	  Softlockups are bugs that cause the kernel to loop in kernel
1099	  mode for more than 20 seconds, without giving other tasks a
1100	  chance to run.  The current stack trace is displayed upon
1101	  detection and the system will stay locked up.
1102
1103config SOFTLOCKUP_DETECTOR_INTR_STORM
1104	bool "Detect Interrupt Storm in Soft Lockups"
1105	depends on SOFTLOCKUP_DETECTOR && IRQ_TIME_ACCOUNTING
1106	select GENERIC_IRQ_STAT_SNAPSHOT
1107	default y if NR_CPUS <= 128
1108	help
1109	  Say Y here to enable the kernel to detect interrupt storm
1110	  during "soft lockups".
1111
1112	  "soft lockups" can be caused by a variety of reasons. If one is
1113	  caused by an interrupt storm, then the storming interrupts will not
1114	  be on the callstack. To detect this case, it is necessary to report
1115	  the CPU stats and the interrupt counts during the "soft lockups".
1116
1117config BOOTPARAM_SOFTLOCKUP_PANIC
1118	bool "Panic (Reboot) On Soft Lockups"
1119	depends on SOFTLOCKUP_DETECTOR
1120	help
1121	  Say Y here to enable the kernel to panic on "soft lockups",
1122	  which are bugs that cause the kernel to loop in kernel
1123	  mode for more than 20 seconds (configurable using the watchdog_thresh
1124	  sysctl), without giving other tasks a chance to run.
1125
1126	  The panic can be used in combination with panic_timeout,
1127	  to cause the system to reboot automatically after a
1128	  lockup has been detected. This feature is useful for
1129	  high-availability systems that have uptime guarantees and
1130	  where a lockup must be resolved ASAP.
1131
1132	  Say N if unsure.
1133
1134config HAVE_HARDLOCKUP_DETECTOR_BUDDY
1135	bool
1136	depends on SMP
1137	default y
1138
1139#
1140# Global switch whether to build a hardlockup detector at all. It is available
1141# only when the architecture supports at least one implementation. There are
1142# two exceptions. The hardlockup detector is never enabled on:
1143#
1144#	s390: it reported many false positives there
1145#
1146#	sparc64: has a custom implementation which is not using the common
1147#		hardlockup command line options and sysctl interface.
1148#
1149config HARDLOCKUP_DETECTOR
1150	bool "Detect Hard Lockups"
1151	depends on DEBUG_KERNEL && !S390 && !HARDLOCKUP_DETECTOR_SPARC64
1152	depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_BUDDY || HAVE_HARDLOCKUP_DETECTOR_ARCH
1153	imply HARDLOCKUP_DETECTOR_PERF
1154	imply HARDLOCKUP_DETECTOR_BUDDY
1155	imply HARDLOCKUP_DETECTOR_ARCH
1156	select LOCKUP_DETECTOR
1157
1158	help
1159	  Say Y here to enable the kernel to act as a watchdog to detect
1160	  hard lockups.
1161
1162	  Hardlockups are bugs that cause the CPU to loop in kernel mode
1163	  for more than 10 seconds, without letting other interrupts have a
1164	  chance to run.  The current stack trace is displayed upon detection
1165	  and the system will stay locked up.
1166
1167#
1168# Note that arch-specific variants are always preferred.
1169#
1170config HARDLOCKUP_DETECTOR_PREFER_BUDDY
1171	bool "Prefer the buddy CPU hardlockup detector"
1172	depends on HARDLOCKUP_DETECTOR
1173	depends on HAVE_HARDLOCKUP_DETECTOR_PERF && HAVE_HARDLOCKUP_DETECTOR_BUDDY
1174	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1175	help
1176	  Say Y here to prefer the buddy hardlockup detector over the perf one.
1177
1178	  With the buddy detector, each CPU uses its softlockup hrtimer
1179	  to check that the next CPU is processing hrtimer interrupts by
1180	  verifying that a counter is increasing.
1181
1182	  This hardlockup detector is useful on systems that don't have
1183	  an arch-specific hardlockup detector or if resources needed
1184	  for the hardlockup detector are better used for other things.
1185
1186config HARDLOCKUP_DETECTOR_PERF
1187	bool
1188	depends on HARDLOCKUP_DETECTOR
1189	depends on HAVE_HARDLOCKUP_DETECTOR_PERF && !HARDLOCKUP_DETECTOR_PREFER_BUDDY
1190	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1191	select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1192
1193config HARDLOCKUP_DETECTOR_BUDDY
1194	bool
1195	depends on HARDLOCKUP_DETECTOR
1196	depends on HAVE_HARDLOCKUP_DETECTOR_BUDDY
1197	depends on !HAVE_HARDLOCKUP_DETECTOR_PERF || HARDLOCKUP_DETECTOR_PREFER_BUDDY
1198	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1199	select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1200
1201config HARDLOCKUP_DETECTOR_ARCH
1202	bool
1203	depends on HARDLOCKUP_DETECTOR
1204	depends on HAVE_HARDLOCKUP_DETECTOR_ARCH
1205	help
1206	  The arch-specific implementation of the hardlockup detector will
1207	  be used.
1208
1209#
1210# Both the "perf" and "buddy" hardlockup detectors count hrtimer
1211# interrupts. This config enables functions managing this common code.
1212#
1213config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1214	bool
1215	select SOFTLOCKUP_DETECTOR
1216
1217#
1218# Enables a timestamp based low pass filter to compensate for perf based
1219# hard lockup detection which runs too fast due to turbo modes.
1220#
1221config HARDLOCKUP_CHECK_TIMESTAMP
1222	bool
1223
1224config BOOTPARAM_HARDLOCKUP_PANIC
1225	bool "Panic (Reboot) On Hard Lockups"
1226	depends on HARDLOCKUP_DETECTOR
1227	help
1228	  Say Y here to enable the kernel to panic on "hard lockups",
1229	  which are bugs that cause the kernel to loop in kernel
1230	  mode with interrupts disabled for more than 10 seconds (configurable
1231	  using the watchdog_thresh sysctl).
1232
1233	  Say N if unsure.
1234
1235config DETECT_HUNG_TASK
1236	bool "Detect Hung Tasks"
1237	depends on DEBUG_KERNEL
1238	default SOFTLOCKUP_DETECTOR
1239	help
1240	  Say Y here to enable the kernel to detect "hung tasks",
1241	  which are bugs that cause the task to be stuck in
1242	  uninterruptible "D" state indefinitely.
1243
1244	  When a hung task is detected, the kernel will print the
1245	  current stack trace (which you should report), but the
1246	  task will stay in uninterruptible state. If lockdep is
1247	  enabled then all held locks will also be reported. This
1248	  feature has negligible overhead.
1249
1250config DEFAULT_HUNG_TASK_TIMEOUT
1251	int "Default timeout for hung task detection (in seconds)"
1252	depends on DETECT_HUNG_TASK
1253	default 120
1254	help
1255	  This option controls the default timeout (in seconds) used
1256	  to determine when a task has become non-responsive and should
1257	  be considered hung.
1258
1259	  It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1260	  sysctl or by writing a value to
1261	  /proc/sys/kernel/hung_task_timeout_secs.
1262
1263	  A timeout of 0 disables the check.  The default is two minutes.
1264	  Keeping the default should be fine in most cases.
1265
1266config BOOTPARAM_HUNG_TASK_PANIC
1267	bool "Panic (Reboot) On Hung Tasks"
1268	depends on DETECT_HUNG_TASK
1269	help
1270	  Say Y here to enable the kernel to panic on "hung tasks",
1271	  which are bugs that cause the kernel to leave a task stuck
1272	  in uninterruptible "D" state.
1273
1274	  The panic can be used in combination with panic_timeout,
1275	  to cause the system to reboot automatically after a
1276	  hung task has been detected. This feature is useful for
1277	  high-availability systems that have uptime guarantees and
1278	  where a hung tasks must be resolved ASAP.
1279
1280	  Say N if unsure.
1281
1282config DETECT_HUNG_TASK_BLOCKER
1283	bool "Dump Hung Tasks Blocker"
1284	depends on DETECT_HUNG_TASK
1285	depends on !PREEMPT_RT
1286	default y
1287	help
1288	  Say Y here to show the blocker task's stacktrace who acquires
1289	  the mutex lock which "hung tasks" are waiting.
1290	  This will add overhead a bit but shows suspicious tasks and
1291	  call trace if it comes from waiting a mutex.
1292
1293config WQ_WATCHDOG
1294	bool "Detect Workqueue Stalls"
1295	depends on DEBUG_KERNEL
1296	help
1297	  Say Y here to enable stall detection on workqueues.  If a
1298	  worker pool doesn't make forward progress on a pending work
1299	  item for over a given amount of time, 30s by default, a
1300	  warning message is printed along with dump of workqueue
1301	  state.  This can be configured through kernel parameter
1302	  "workqueue.watchdog_thresh" and its sysfs counterpart.
1303
1304config WQ_CPU_INTENSIVE_REPORT
1305	bool "Report per-cpu work items which hog CPU for too long"
1306	depends on DEBUG_KERNEL
1307	help
1308	  Say Y here to enable reporting of concurrency-managed per-cpu work
1309	  items that hog CPUs for longer than
1310	  workqueue.cpu_intensive_thresh_us. Workqueue automatically
1311	  detects and excludes them from concurrency management to prevent
1312	  them from stalling other per-cpu work items. Occassional
1313	  triggering may not necessarily indicate a problem. Repeated
1314	  triggering likely indicates that the work item should be switched
1315	  to use an unbound workqueue.
1316
1317config TEST_LOCKUP
1318	tristate "Test module to generate lockups"
1319	depends on m
1320	help
1321	  This builds the "test_lockup" module that helps to make sure
1322	  that watchdogs and lockup detectors are working properly.
1323
1324	  Depending on module parameters it could emulate soft or hard
1325	  lockup, "hung task", or locking arbitrary lock for a long time.
1326	  Also it could generate series of lockups with cooling-down periods.
1327
1328	  If unsure, say N.
1329
1330endmenu # "Debug lockups and hangs"
1331
1332menu "Scheduler Debugging"
1333
1334config SCHED_INFO
1335	bool
1336	default n
1337
1338config SCHEDSTATS
1339	bool "Collect scheduler statistics"
1340	depends on PROC_FS
1341	select SCHED_INFO
1342	help
1343	  If you say Y here, additional code will be inserted into the
1344	  scheduler and related routines to collect statistics about
1345	  scheduler behavior and provide them in /proc/schedstat.  These
1346	  stats may be useful for both tuning and debugging the scheduler
1347	  If you aren't debugging the scheduler or trying to tune a specific
1348	  application, you can say N to avoid the very slight overhead
1349	  this adds.
1350
1351endmenu
1352
1353config DEBUG_PREEMPT
1354	bool "Debug preemptible kernel"
1355	depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1356	help
1357	  If you say Y here then the kernel will use a debug variant of the
1358	  commonly used smp_processor_id() function and will print warnings
1359	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
1360	  will detect preemption count underflows.
1361
1362	  This option has potential to introduce high runtime overhead,
1363	  depending on workload as it triggers debugging routines for each
1364	  this_cpu operation. It should only be used for debugging purposes.
1365
1366menu "Lock Debugging (spinlocks, mutexes, etc...)"
1367
1368config LOCK_DEBUGGING_SUPPORT
1369	bool
1370	depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1371	default y
1372
1373config PROVE_LOCKING
1374	bool "Lock debugging: prove locking correctness"
1375	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1376	select LOCKDEP
1377	select DEBUG_SPINLOCK
1378	select DEBUG_MUTEXES if !PREEMPT_RT
1379	select DEBUG_RT_MUTEXES if RT_MUTEXES
1380	select DEBUG_RWSEMS if !PREEMPT_RT
1381	select DEBUG_WW_MUTEX_SLOWPATH
1382	select DEBUG_LOCK_ALLOC
1383	select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1384	select TRACE_IRQFLAGS
1385	default n
1386	help
1387	 This feature enables the kernel to prove that all locking
1388	 that occurs in the kernel runtime is mathematically
1389	 correct: that under no circumstance could an arbitrary (and
1390	 not yet triggered) combination of observed locking
1391	 sequences (on an arbitrary number of CPUs, running an
1392	 arbitrary number of tasks and interrupt contexts) cause a
1393	 deadlock.
1394
1395	 In short, this feature enables the kernel to report locking
1396	 related deadlocks before they actually occur.
1397
1398	 The proof does not depend on how hard and complex a
1399	 deadlock scenario would be to trigger: how many
1400	 participant CPUs, tasks and irq-contexts would be needed
1401	 for it to trigger. The proof also does not depend on
1402	 timing: if a race and a resulting deadlock is possible
1403	 theoretically (no matter how unlikely the race scenario
1404	 is), it will be proven so and will immediately be
1405	 reported by the kernel (once the event is observed that
1406	 makes the deadlock theoretically possible).
1407
1408	 If a deadlock is impossible (i.e. the locking rules, as
1409	 observed by the kernel, are mathematically correct), the
1410	 kernel reports nothing.
1411
1412	 NOTE: this feature can also be enabled for rwlocks, mutexes
1413	 and rwsems - in which case all dependencies between these
1414	 different locking variants are observed and mapped too, and
1415	 the proof of observed correctness is also maintained for an
1416	 arbitrary combination of these separate locking variants.
1417
1418	 For more details, see Documentation/locking/lockdep-design.rst.
1419
1420config PROVE_RAW_LOCK_NESTING
1421	bool "Enable raw_spinlock - spinlock nesting checks" if !ARCH_SUPPORTS_RT
1422	depends on PROVE_LOCKING
1423	default y if ARCH_SUPPORTS_RT
1424	help
1425	 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1426	 that the lock nesting rules for PREEMPT_RT enabled kernels are
1427	 not violated.
1428
1429config LOCK_STAT
1430	bool "Lock usage statistics"
1431	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1432	select LOCKDEP
1433	select DEBUG_SPINLOCK
1434	select DEBUG_MUTEXES if !PREEMPT_RT
1435	select DEBUG_RT_MUTEXES if RT_MUTEXES
1436	select DEBUG_LOCK_ALLOC
1437	default n
1438	help
1439	 This feature enables tracking lock contention points
1440
1441	 For more details, see Documentation/locking/lockstat.rst
1442
1443	 This also enables lock events required by "perf lock",
1444	 subcommand of perf.
1445	 If you want to use "perf lock", you also need to turn on
1446	 CONFIG_EVENT_TRACING.
1447
1448	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1449	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1450
1451config DEBUG_RT_MUTEXES
1452	bool "RT Mutex debugging, deadlock detection"
1453	depends on DEBUG_KERNEL && RT_MUTEXES
1454	help
1455	 This allows rt mutex semantics violations and rt mutex related
1456	 deadlocks (lockups) to be detected and reported automatically.
1457
1458config DEBUG_SPINLOCK
1459	bool "Spinlock and rw-lock debugging: basic checks"
1460	depends on DEBUG_KERNEL
1461	select UNINLINE_SPIN_UNLOCK
1462	help
1463	  Say Y here and build SMP to catch missing spinlock initialization
1464	  and certain other kinds of spinlock errors commonly made.  This is
1465	  best used in conjunction with the NMI watchdog so that spinlock
1466	  deadlocks are also debuggable.
1467
1468config DEBUG_MUTEXES
1469	bool "Mutex debugging: basic checks"
1470	depends on DEBUG_KERNEL && !PREEMPT_RT
1471	help
1472	 This feature allows mutex semantics violations to be detected and
1473	 reported.
1474
1475config DEBUG_WW_MUTEX_SLOWPATH
1476	bool "Wait/wound mutex debugging: Slowpath testing"
1477	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1478	select DEBUG_LOCK_ALLOC
1479	select DEBUG_SPINLOCK
1480	select DEBUG_MUTEXES if !PREEMPT_RT
1481	select DEBUG_RT_MUTEXES if PREEMPT_RT
1482	help
1483	 This feature enables slowpath testing for w/w mutex users by
1484	 injecting additional -EDEADLK wound/backoff cases. Together with
1485	 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1486	 will test all possible w/w mutex interface abuse with the
1487	 exception of simply not acquiring all the required locks.
1488	 Note that this feature can introduce significant overhead, so
1489	 it really should not be enabled in a production or distro kernel,
1490	 even a debug kernel.  If you are a driver writer, enable it.  If
1491	 you are a distro, do not.
1492
1493config DEBUG_RWSEMS
1494	bool "RW Semaphore debugging: basic checks"
1495	depends on DEBUG_KERNEL && !PREEMPT_RT
1496	help
1497	  This debugging feature allows mismatched rw semaphore locks
1498	  and unlocks to be detected and reported.
1499
1500config DEBUG_LOCK_ALLOC
1501	bool "Lock debugging: detect incorrect freeing of live locks"
1502	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1503	select DEBUG_SPINLOCK
1504	select DEBUG_MUTEXES if !PREEMPT_RT
1505	select DEBUG_RT_MUTEXES if RT_MUTEXES
1506	select LOCKDEP
1507	help
1508	 This feature will check whether any held lock (spinlock, rwlock,
1509	 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1510	 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1511	 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1512	 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1513	 held during task exit.
1514
1515config LOCKDEP
1516	bool
1517	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1518	select STACKTRACE
1519	select KALLSYMS
1520	select KALLSYMS_ALL
1521
1522config LOCKDEP_SMALL
1523	bool
1524
1525config LOCKDEP_BITS
1526	int "Size for MAX_LOCKDEP_ENTRIES (as Nth power of 2)"
1527	depends on LOCKDEP && !LOCKDEP_SMALL
1528	range 10 24
1529	default 15
1530	help
1531	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1532
1533config LOCKDEP_CHAINS_BITS
1534	int "Size for MAX_LOCKDEP_CHAINS (as Nth power of 2)"
1535	depends on LOCKDEP && !LOCKDEP_SMALL
1536	range 10 21
1537	default 16
1538	help
1539	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1540
1541config LOCKDEP_STACK_TRACE_BITS
1542	int "Size for MAX_STACK_TRACE_ENTRIES (as Nth power of 2)"
1543	depends on LOCKDEP && !LOCKDEP_SMALL
1544	range 10 26
1545	default 19
1546	help
1547	  Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1548
1549config LOCKDEP_STACK_TRACE_HASH_BITS
1550	int "Size for STACK_TRACE_HASH_SIZE (as Nth power of 2)"
1551	depends on LOCKDEP && !LOCKDEP_SMALL
1552	range 10 26
1553	default 14
1554	help
1555	  Try increasing this value if you need large STACK_TRACE_HASH_SIZE.
1556
1557config LOCKDEP_CIRCULAR_QUEUE_BITS
1558	int "Size for elements in circular_queue struct (as Nth power of 2)"
1559	depends on LOCKDEP
1560	range 10 26
1561	default 12
1562	help
1563	  Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1564
1565config DEBUG_LOCKDEP
1566	bool "Lock dependency engine debugging"
1567	depends on DEBUG_KERNEL && LOCKDEP
1568	select DEBUG_IRQFLAGS
1569	help
1570	  If you say Y here, the lock dependency engine will do
1571	  additional runtime checks to debug itself, at the price
1572	  of more runtime overhead.
1573
1574config DEBUG_ATOMIC_SLEEP
1575	bool "Sleep inside atomic section checking"
1576	select PREEMPT_COUNT
1577	depends on DEBUG_KERNEL
1578	depends on !ARCH_NO_PREEMPT
1579	help
1580	  If you say Y here, various routines which may sleep will become very
1581	  noisy if they are called inside atomic sections: when a spinlock is
1582	  held, inside an rcu read side critical section, inside preempt disabled
1583	  sections, inside an interrupt, etc...
1584
1585config DEBUG_LOCKING_API_SELFTESTS
1586	bool "Locking API boot-time self-tests"
1587	depends on DEBUG_KERNEL
1588	help
1589	  Say Y here if you want the kernel to run a short self-test during
1590	  bootup. The self-test checks whether common types of locking bugs
1591	  are detected by debugging mechanisms or not. (if you disable
1592	  lock debugging then those bugs won't be detected of course.)
1593	  The following locking APIs are covered: spinlocks, rwlocks,
1594	  mutexes and rwsems.
1595
1596config LOCK_TORTURE_TEST
1597	tristate "torture tests for locking"
1598	depends on DEBUG_KERNEL
1599	select TORTURE_TEST
1600	help
1601	  This option provides a kernel module that runs torture tests
1602	  on kernel locking primitives.  The kernel module may be built
1603	  after the fact on the running kernel to be tested, if desired.
1604
1605	  Say Y here if you want kernel locking-primitive torture tests
1606	  to be built into the kernel.
1607	  Say M if you want these torture tests to build as a module.
1608	  Say N if you are unsure.
1609
1610config WW_MUTEX_SELFTEST
1611	tristate "Wait/wound mutex selftests"
1612	help
1613	  This option provides a kernel module that runs tests on the
1614	  on the struct ww_mutex locking API.
1615
1616	  It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1617	  with this test harness.
1618
1619	  Say M if you want these self tests to build as a module.
1620	  Say N if you are unsure.
1621
1622config SCF_TORTURE_TEST
1623	tristate "torture tests for smp_call_function*()"
1624	depends on DEBUG_KERNEL
1625	select TORTURE_TEST
1626	help
1627	  This option provides a kernel module that runs torture tests
1628	  on the smp_call_function() family of primitives.  The kernel
1629	  module may be built after the fact on the running kernel to
1630	  be tested, if desired.
1631
1632config CSD_LOCK_WAIT_DEBUG
1633	bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1634	depends on DEBUG_KERNEL
1635	depends on SMP
1636	depends on 64BIT
1637	default n
1638	help
1639	  This option enables debug prints when CPUs are slow to respond
1640	  to the smp_call_function*() IPI wrappers.  These debug prints
1641	  include the IPI handler function currently executing (if any)
1642	  and relevant stack traces.
1643
1644config CSD_LOCK_WAIT_DEBUG_DEFAULT
1645	bool "Default csd_lock_wait() debugging on at boot time"
1646	depends on CSD_LOCK_WAIT_DEBUG
1647	depends on 64BIT
1648	default n
1649	help
1650	  This option causes the csdlock_debug= kernel boot parameter to
1651	  default to 1 (basic debugging) instead of 0 (no debugging).
1652
1653endmenu # lock debugging
1654
1655config TRACE_IRQFLAGS
1656	depends on TRACE_IRQFLAGS_SUPPORT
1657	bool
1658	help
1659	  Enables hooks to interrupt enabling and disabling for
1660	  either tracing or lock debugging.
1661
1662config TRACE_IRQFLAGS_NMI
1663	def_bool y
1664	depends on TRACE_IRQFLAGS
1665	depends on TRACE_IRQFLAGS_NMI_SUPPORT
1666
1667config NMI_CHECK_CPU
1668	bool "Debugging for CPUs failing to respond to backtrace requests"
1669	depends on DEBUG_KERNEL
1670	depends on X86
1671	default n
1672	help
1673	  Enables debug prints when a CPU fails to respond to a given
1674	  backtrace NMI.  These prints provide some reasons why a CPU
1675	  might legitimately be failing to respond, for example, if it
1676	  is offline of if ignore_nmis is set.
1677
1678config DEBUG_IRQFLAGS
1679	bool "Debug IRQ flag manipulation"
1680	help
1681	  Enables checks for potentially unsafe enabling or disabling of
1682	  interrupts, such as calling raw_local_irq_restore() when interrupts
1683	  are enabled.
1684
1685config STACKTRACE
1686	bool "Stack backtrace support"
1687	depends on STACKTRACE_SUPPORT
1688	help
1689	  This option causes the kernel to create a /proc/pid/stack for
1690	  every process, showing its current stack trace.
1691	  It is also used by various kernel debugging features that require
1692	  stack trace generation.
1693
1694config WARN_ALL_UNSEEDED_RANDOM
1695	bool "Warn for all uses of unseeded randomness"
1696	default n
1697	help
1698	  Some parts of the kernel contain bugs relating to their use of
1699	  cryptographically secure random numbers before it's actually possible
1700	  to generate those numbers securely. This setting ensures that these
1701	  flaws don't go unnoticed, by enabling a message, should this ever
1702	  occur. This will allow people with obscure setups to know when things
1703	  are going wrong, so that they might contact developers about fixing
1704	  it.
1705
1706	  Unfortunately, on some models of some architectures getting
1707	  a fully seeded CRNG is extremely difficult, and so this can
1708	  result in dmesg getting spammed for a surprisingly long
1709	  time.  This is really bad from a security perspective, and
1710	  so architecture maintainers really need to do what they can
1711	  to get the CRNG seeded sooner after the system is booted.
1712	  However, since users cannot do anything actionable to
1713	  address this, by default this option is disabled.
1714
1715	  Say Y here if you want to receive warnings for all uses of
1716	  unseeded randomness.  This will be of use primarily for
1717	  those developers interested in improving the security of
1718	  Linux kernels running on their architecture (or
1719	  subarchitecture).
1720
1721config DEBUG_KOBJECT
1722	bool "kobject debugging"
1723	depends on DEBUG_KERNEL
1724	help
1725	  If you say Y here, some extra kobject debugging messages will be sent
1726	  to the syslog.
1727
1728config DEBUG_KOBJECT_RELEASE
1729	bool "kobject release debugging"
1730	depends on DEBUG_OBJECTS_TIMERS
1731	help
1732	  kobjects are reference counted objects.  This means that their
1733	  last reference count put is not predictable, and the kobject can
1734	  live on past the point at which a driver decides to drop its
1735	  initial reference to the kobject gained on allocation.  An
1736	  example of this would be a struct device which has just been
1737	  unregistered.
1738
1739	  However, some buggy drivers assume that after such an operation,
1740	  the memory backing the kobject can be immediately freed.  This
1741	  goes completely against the principles of a refcounted object.
1742
1743	  If you say Y here, the kernel will delay the release of kobjects
1744	  on the last reference count to improve the visibility of this
1745	  kind of kobject release bug.
1746
1747config HAVE_DEBUG_BUGVERBOSE
1748	bool
1749
1750menu "Debug kernel data structures"
1751
1752config DEBUG_LIST
1753	bool "Debug linked list manipulation"
1754	depends on DEBUG_KERNEL
1755	select LIST_HARDENED
1756	help
1757	  Enable this to turn on extended checks in the linked-list walking
1758	  routines.
1759
1760	  This option trades better quality error reports for performance, and
1761	  is more suitable for kernel debugging. If you care about performance,
1762	  you should only enable CONFIG_LIST_HARDENED instead.
1763
1764	  If unsure, say N.
1765
1766config DEBUG_PLIST
1767	bool "Debug priority linked list manipulation"
1768	depends on DEBUG_KERNEL
1769	help
1770	  Enable this to turn on extended checks in the priority-ordered
1771	  linked-list (plist) walking routines.  This checks the entire
1772	  list multiple times during each manipulation.
1773
1774	  If unsure, say N.
1775
1776config DEBUG_SG
1777	bool "Debug SG table operations"
1778	depends on DEBUG_KERNEL
1779	help
1780	  Enable this to turn on checks on scatter-gather tables. This can
1781	  help find problems with drivers that do not properly initialize
1782	  their sg tables.
1783
1784	  If unsure, say N.
1785
1786config DEBUG_NOTIFIERS
1787	bool "Debug notifier call chains"
1788	depends on DEBUG_KERNEL
1789	help
1790	  Enable this to turn on sanity checking for notifier call chains.
1791	  This is most useful for kernel developers to make sure that
1792	  modules properly unregister themselves from notifier chains.
1793	  This is a relatively cheap check but if you care about maximum
1794	  performance, say N.
1795
1796config DEBUG_CLOSURES
1797	bool "Debug closures (bcache async widgits)"
1798	depends on CLOSURES
1799	select DEBUG_FS
1800	help
1801	  Keeps all active closures in a linked list and provides a debugfs
1802	  interface to list them, which makes it possible to see asynchronous
1803	  operations that get stuck.
1804
1805config DEBUG_MAPLE_TREE
1806	bool "Debug maple trees"
1807	depends on DEBUG_KERNEL
1808	help
1809	  Enable maple tree debugging information and extra validations.
1810
1811	  If unsure, say N.
1812
1813endmenu
1814
1815source "kernel/rcu/Kconfig.debug"
1816
1817config DEBUG_WQ_FORCE_RR_CPU
1818	bool "Force round-robin CPU selection for unbound work items"
1819	depends on DEBUG_KERNEL
1820	default n
1821	help
1822	  Workqueue used to implicitly guarantee that work items queued
1823	  without explicit CPU specified are put on the local CPU.  This
1824	  guarantee is no longer true and while local CPU is still
1825	  preferred work items may be put on foreign CPUs.  Kernel
1826	  parameter "workqueue.debug_force_rr_cpu" is added to force
1827	  round-robin CPU selection to flush out usages which depend on the
1828	  now broken guarantee.  This config option enables the debug
1829	  feature by default.  When enabled, memory and cache locality will
1830	  be impacted.
1831
1832config CPU_HOTPLUG_STATE_CONTROL
1833	bool "Enable CPU hotplug state control"
1834	depends on DEBUG_KERNEL
1835	depends on HOTPLUG_CPU
1836	default n
1837	help
1838	  Allows to write steps between "offline" and "online" to the CPUs
1839	  sysfs target file so states can be stepped granular. This is a debug
1840	  option for now as the hotplug machinery cannot be stopped and
1841	  restarted at arbitrary points yet.
1842
1843	  Say N if your are unsure.
1844
1845config LATENCYTOP
1846	bool "Latency measuring infrastructure"
1847	depends on DEBUG_KERNEL
1848	depends on STACKTRACE_SUPPORT
1849	depends on PROC_FS
1850	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1851	select KALLSYMS
1852	select KALLSYMS_ALL
1853	select STACKTRACE
1854	select SCHEDSTATS
1855	help
1856	  Enable this option if you want to use the LatencyTOP tool
1857	  to find out which userspace is blocking on what kernel operations.
1858
1859config DEBUG_CGROUP_REF
1860	bool "Disable inlining of cgroup css reference count functions"
1861	depends on DEBUG_KERNEL
1862	depends on CGROUPS
1863	depends on KPROBES
1864	default n
1865	help
1866	  Force cgroup css reference count functions to not be inlined so
1867	  that they can be kprobed for debugging.
1868
1869source "kernel/trace/Kconfig"
1870
1871config PROVIDE_OHCI1394_DMA_INIT
1872	bool "Remote debugging over FireWire early on boot"
1873	depends on PCI && X86
1874	help
1875	  If you want to debug problems which hang or crash the kernel early
1876	  on boot and the crashing machine has a FireWire port, you can use
1877	  this feature to remotely access the memory of the crashed machine
1878	  over FireWire. This employs remote DMA as part of the OHCI1394
1879	  specification which is now the standard for FireWire controllers.
1880
1881	  With remote DMA, you can monitor the printk buffer remotely using
1882	  firescope and access all memory below 4GB using fireproxy from gdb.
1883	  Even controlling a kernel debugger is possible using remote DMA.
1884
1885	  Usage:
1886
1887	  If ohci1394_dma=early is used as boot parameter, it will initialize
1888	  all OHCI1394 controllers which are found in the PCI config space.
1889
1890	  As all changes to the FireWire bus such as enabling and disabling
1891	  devices cause a bus reset and thereby disable remote DMA for all
1892	  devices, be sure to have the cable plugged and FireWire enabled on
1893	  the debugging host before booting the debug target for debugging.
1894
1895	  This code (~1k) is freed after boot. By then, the firewire stack
1896	  in charge of the OHCI-1394 controllers should be used instead.
1897
1898	  See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1899
1900source "samples/Kconfig"
1901
1902config ARCH_HAS_DEVMEM_IS_ALLOWED
1903	bool
1904
1905config STRICT_DEVMEM
1906	bool "Filter access to /dev/mem"
1907	depends on MMU && DEVMEM
1908	depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1909	default y if PPC || X86 || ARM64 || S390
1910	help
1911	  If this option is disabled, you allow userspace (root) access to all
1912	  of memory, including kernel and userspace memory. Accidental
1913	  access to this is obviously disastrous, but specific access can
1914	  be used by people debugging the kernel. Note that with PAT support
1915	  enabled, even in this case there are restrictions on /dev/mem
1916	  use due to the cache aliasing requirements.
1917
1918	  If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1919	  file only allows userspace access to PCI space and the BIOS code and
1920	  data regions.  This is sufficient for dosemu and X and all common
1921	  users of /dev/mem.
1922
1923	  If in doubt, say Y.
1924
1925config IO_STRICT_DEVMEM
1926	bool "Filter I/O access to /dev/mem"
1927	depends on STRICT_DEVMEM
1928	help
1929	  If this option is disabled, you allow userspace (root) access to all
1930	  io-memory regardless of whether a driver is actively using that
1931	  range.  Accidental access to this is obviously disastrous, but
1932	  specific access can be used by people debugging kernel drivers.
1933
1934	  If this option is switched on, the /dev/mem file only allows
1935	  userspace access to *idle* io-memory ranges (see /proc/iomem) This
1936	  may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1937	  if the driver using a given range cannot be disabled.
1938
1939	  If in doubt, say Y.
1940
1941menu "$(SRCARCH) Debugging"
1942
1943source "arch/$(SRCARCH)/Kconfig.debug"
1944
1945endmenu
1946
1947menu "Kernel Testing and Coverage"
1948
1949source "lib/kunit/Kconfig"
1950
1951config NOTIFIER_ERROR_INJECTION
1952	tristate "Notifier error injection"
1953	depends on DEBUG_KERNEL
1954	select DEBUG_FS
1955	help
1956	  This option provides the ability to inject artificial errors to
1957	  specified notifier chain callbacks. It is useful to test the error
1958	  handling of notifier call chain failures.
1959
1960	  Say N if unsure.
1961
1962config PM_NOTIFIER_ERROR_INJECT
1963	tristate "PM notifier error injection module"
1964	depends on PM && NOTIFIER_ERROR_INJECTION
1965	default m if PM_DEBUG
1966	help
1967	  This option provides the ability to inject artificial errors to
1968	  PM notifier chain callbacks.  It is controlled through debugfs
1969	  interface /sys/kernel/debug/notifier-error-inject/pm
1970
1971	  If the notifier call chain should be failed with some events
1972	  notified, write the error code to "actions/<notifier event>/error".
1973
1974	  Example: Inject PM suspend error (-12 = -ENOMEM)
1975
1976	  # cd /sys/kernel/debug/notifier-error-inject/pm/
1977	  # echo -12 > actions/PM_SUSPEND_PREPARE/error
1978	  # echo mem > /sys/power/state
1979	  bash: echo: write error: Cannot allocate memory
1980
1981	  To compile this code as a module, choose M here: the module will
1982	  be called pm-notifier-error-inject.
1983
1984	  If unsure, say N.
1985
1986config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1987	tristate "OF reconfig notifier error injection module"
1988	depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1989	help
1990	  This option provides the ability to inject artificial errors to
1991	  OF reconfig notifier chain callbacks.  It is controlled
1992	  through debugfs interface under
1993	  /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1994
1995	  If the notifier call chain should be failed with some events
1996	  notified, write the error code to "actions/<notifier event>/error".
1997
1998	  To compile this code as a module, choose M here: the module will
1999	  be called of-reconfig-notifier-error-inject.
2000
2001	  If unsure, say N.
2002
2003config NETDEV_NOTIFIER_ERROR_INJECT
2004	tristate "Netdev notifier error injection module"
2005	depends on NET && NOTIFIER_ERROR_INJECTION
2006	help
2007	  This option provides the ability to inject artificial errors to
2008	  netdevice notifier chain callbacks.  It is controlled through debugfs
2009	  interface /sys/kernel/debug/notifier-error-inject/netdev
2010
2011	  If the notifier call chain should be failed with some events
2012	  notified, write the error code to "actions/<notifier event>/error".
2013
2014	  Example: Inject netdevice mtu change error (-22 = -EINVAL)
2015
2016	  # cd /sys/kernel/debug/notifier-error-inject/netdev
2017	  # echo -22 > actions/NETDEV_CHANGEMTU/error
2018	  # ip link set eth0 mtu 1024
2019	  RTNETLINK answers: Invalid argument
2020
2021	  To compile this code as a module, choose M here: the module will
2022	  be called netdev-notifier-error-inject.
2023
2024	  If unsure, say N.
2025
2026config FUNCTION_ERROR_INJECTION
2027	bool "Fault-injections of functions"
2028	depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
2029	help
2030	  Add fault injections into various functions that are annotated with
2031	  ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
2032	  value of these functions. This is useful to test error paths of code.
2033
2034	  If unsure, say N
2035
2036config FAULT_INJECTION
2037	bool "Fault-injection framework"
2038	depends on DEBUG_KERNEL
2039	help
2040	  Provide fault-injection framework.
2041	  For more details, see Documentation/fault-injection/.
2042
2043config FAILSLAB
2044	bool "Fault-injection capability for kmalloc"
2045	depends on FAULT_INJECTION
2046	help
2047	  Provide fault-injection capability for kmalloc.
2048
2049config FAIL_PAGE_ALLOC
2050	bool "Fault-injection capability for alloc_pages()"
2051	depends on FAULT_INJECTION
2052	help
2053	  Provide fault-injection capability for alloc_pages().
2054
2055config FAULT_INJECTION_USERCOPY
2056	bool "Fault injection capability for usercopy functions"
2057	depends on FAULT_INJECTION
2058	help
2059	  Provides fault-injection capability to inject failures
2060	  in usercopy functions (copy_from_user(), get_user(), ...).
2061
2062config FAIL_MAKE_REQUEST
2063	bool "Fault-injection capability for disk IO"
2064	depends on FAULT_INJECTION && BLOCK
2065	help
2066	  Provide fault-injection capability for disk IO.
2067
2068config FAIL_IO_TIMEOUT
2069	bool "Fault-injection capability for faking disk interrupts"
2070	depends on FAULT_INJECTION && BLOCK
2071	help
2072	  Provide fault-injection capability on end IO handling. This
2073	  will make the block layer "forget" an interrupt as configured,
2074	  thus exercising the error handling.
2075
2076	  Only works with drivers that use the generic timeout handling,
2077	  for others it won't do anything.
2078
2079config FAIL_FUTEX
2080	bool "Fault-injection capability for futexes"
2081	select DEBUG_FS
2082	depends on FAULT_INJECTION && FUTEX
2083	help
2084	  Provide fault-injection capability for futexes.
2085
2086config FAULT_INJECTION_DEBUG_FS
2087	bool "Debugfs entries for fault-injection capabilities"
2088	depends on FAULT_INJECTION && SYSFS && DEBUG_FS
2089	help
2090	  Enable configuration of fault-injection capabilities via debugfs.
2091
2092config FAIL_FUNCTION
2093	bool "Fault-injection capability for functions"
2094	depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
2095	help
2096	  Provide function-based fault-injection capability.
2097	  This will allow you to override a specific function with a return
2098	  with given return value. As a result, function caller will see
2099	  an error value and have to handle it. This is useful to test the
2100	  error handling in various subsystems.
2101
2102config FAIL_MMC_REQUEST
2103	bool "Fault-injection capability for MMC IO"
2104	depends on FAULT_INJECTION_DEBUG_FS && MMC
2105	help
2106	  Provide fault-injection capability for MMC IO.
2107	  This will make the mmc core return data errors. This is
2108	  useful to test the error handling in the mmc block device
2109	  and to test how the mmc host driver handles retries from
2110	  the block device.
2111
2112config FAIL_SUNRPC
2113	bool "Fault-injection capability for SunRPC"
2114	depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2115	help
2116	  Provide fault-injection capability for SunRPC and
2117	  its consumers.
2118
2119config FAIL_SKB_REALLOC
2120	bool "Fault-injection capability forcing skb to reallocate"
2121	depends on FAULT_INJECTION_DEBUG_FS
2122	help
2123	  Provide fault-injection capability that forces the skb to be
2124	  reallocated, catching possible invalid pointers to the skb.
2125
2126	  For more information, check
2127	  Documentation/fault-injection/fault-injection.rst
2128
2129config FAULT_INJECTION_CONFIGFS
2130	bool "Configfs interface for fault-injection capabilities"
2131	depends on FAULT_INJECTION
2132	select CONFIGFS_FS
2133	help
2134	  This option allows configfs-based drivers to dynamically configure
2135	  fault-injection via configfs.  Each parameter for driver-specific
2136	  fault-injection can be made visible as a configfs attribute in a
2137	  configfs group.
2138
2139
2140config FAULT_INJECTION_STACKTRACE_FILTER
2141	bool "stacktrace filter for fault-injection capabilities"
2142	depends on FAULT_INJECTION
2143	depends on (FAULT_INJECTION_DEBUG_FS || FAULT_INJECTION_CONFIGFS) && STACKTRACE_SUPPORT
2144	select STACKTRACE
2145	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2146	help
2147	  Provide stacktrace filter for fault-injection capabilities
2148
2149config ARCH_HAS_KCOV
2150	bool
2151	help
2152	  An architecture should select this when it can successfully
2153	  build and run with CONFIG_KCOV. This typically requires
2154	  disabling instrumentation for some early boot code.
2155
2156config CC_HAS_SANCOV_TRACE_PC
2157	def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2158
2159
2160config KCOV
2161	bool "Code coverage for fuzzing"
2162	depends on ARCH_HAS_KCOV
2163	depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2164	depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2165		   GCC_VERSION >= 120000 || CC_IS_CLANG
2166	select DEBUG_FS
2167	select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2168	select OBJTOOL if HAVE_NOINSTR_HACK
2169	help
2170	  KCOV exposes kernel code coverage information in a form suitable
2171	  for coverage-guided fuzzing (randomized testing).
2172
2173	  For more details, see Documentation/dev-tools/kcov.rst.
2174
2175config KCOV_ENABLE_COMPARISONS
2176	bool "Enable comparison operands collection by KCOV"
2177	depends on KCOV
2178	depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2179	help
2180	  KCOV also exposes operands of every comparison in the instrumented
2181	  code along with operand sizes and PCs of the comparison instructions.
2182	  These operands can be used by fuzzing engines to improve the quality
2183	  of fuzzing coverage.
2184
2185config KCOV_INSTRUMENT_ALL
2186	bool "Instrument all code by default"
2187	depends on KCOV
2188	default y
2189	help
2190	  If you are doing generic system call fuzzing (like e.g. syzkaller),
2191	  then you will want to instrument the whole kernel and you should
2192	  say y here. If you are doing more targeted fuzzing (like e.g.
2193	  filesystem fuzzing with AFL) then you will want to enable coverage
2194	  for more specific subsets of files, and should say n here.
2195
2196config KCOV_IRQ_AREA_SIZE
2197	hex "Size of interrupt coverage collection area in words"
2198	depends on KCOV
2199	default 0x40000
2200	help
2201	  KCOV uses preallocated per-cpu areas to collect coverage from
2202	  soft interrupts. This specifies the size of those areas in the
2203	  number of unsigned long words.
2204
2205config KCOV_SELFTEST
2206	bool "Perform short selftests on boot"
2207	depends on KCOV
2208	help
2209	  Run short KCOV coverage collection selftests on boot.
2210	  On test failure, causes the kernel to panic. Recommended to be
2211	  enabled, ensuring critical functionality works as intended.
2212
2213menuconfig RUNTIME_TESTING_MENU
2214	bool "Runtime Testing"
2215	default y
2216
2217if RUNTIME_TESTING_MENU
2218
2219config TEST_DHRY
2220	tristate "Dhrystone benchmark test"
2221	help
2222	  Enable this to include the Dhrystone 2.1 benchmark.  This test
2223	  calculates the number of Dhrystones per second, and the number of
2224	  DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided
2225	  by 1757 (the number of Dhrystones per second obtained on the VAX
2226	  11/780, nominally a 1 MIPS machine).
2227
2228	  To run the benchmark, it needs to be enabled explicitly, either from
2229	  the kernel command line (when built-in), or from userspace (when
2230	  built-in or modular).
2231
2232	  Run once during kernel boot:
2233
2234	      test_dhry.run
2235
2236	  Set number of iterations from kernel command line:
2237
2238	      test_dhry.iterations=<n>
2239
2240	  Set number of iterations from userspace:
2241
2242	      echo <n> > /sys/module/test_dhry/parameters/iterations
2243
2244	  Trigger manual run from userspace:
2245
2246	      echo y > /sys/module/test_dhry/parameters/run
2247
2248	  If the number of iterations is <= 0, the test will devise a suitable
2249	  number of iterations (test runs for at least 2s) automatically.
2250	  This process takes ca. 4s.
2251
2252	  If unsure, say N.
2253
2254config LKDTM
2255	tristate "Linux Kernel Dump Test Tool Module"
2256	depends on DEBUG_FS
2257	help
2258	This module enables testing of the different dumping mechanisms by
2259	inducing system failures at predefined crash points.
2260	If you don't need it: say N
2261	Choose M here to compile this code as a module. The module will be
2262	called lkdtm.
2263
2264	Documentation on how to use the module can be found in
2265	Documentation/fault-injection/provoke-crashes.rst
2266
2267config CPUMASK_KUNIT_TEST
2268	tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2269	depends on KUNIT
2270	default KUNIT_ALL_TESTS
2271	help
2272	  Enable to turn on cpumask tests, running at boot or module load time.
2273
2274	  For more information on KUnit and unit tests in general, please refer
2275	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2276
2277	  If unsure, say N.
2278
2279config TEST_LIST_SORT
2280	tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2281	depends on KUNIT
2282	default KUNIT_ALL_TESTS
2283	help
2284	  Enable this to turn on 'list_sort()' function test. This test is
2285	  executed only once during system boot (so affects only boot time),
2286	  or at module load time.
2287
2288	  If unsure, say N.
2289
2290config TEST_MIN_HEAP
2291	tristate "Min heap test"
2292	depends on DEBUG_KERNEL || m
2293	help
2294	  Enable this to turn on min heap function tests. This test is
2295	  executed only once during system boot (so affects only boot time),
2296	  or at module load time.
2297
2298	  If unsure, say N.
2299
2300config TEST_SORT
2301	tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2302	depends on KUNIT
2303	default KUNIT_ALL_TESTS
2304	help
2305	  This option enables the self-test function of 'sort()' at boot,
2306	  or at module load time.
2307
2308	  If unsure, say N.
2309
2310config TEST_DIV64
2311	tristate "64bit/32bit division and modulo test"
2312	depends on DEBUG_KERNEL || m
2313	help
2314	  Enable this to turn on 'do_div()' function test. This test is
2315	  executed only once during system boot (so affects only boot time),
2316	  or at module load time.
2317
2318	  If unsure, say N.
2319
2320config TEST_MULDIV64
2321	tristate "mul_u64_u64_div_u64() test"
2322	depends on DEBUG_KERNEL || m
2323	help
2324	  Enable this to turn on 'mul_u64_u64_div_u64()' function test.
2325	  This test is executed only once during system boot (so affects
2326	  only boot time), or at module load time.
2327
2328	  If unsure, say N.
2329
2330config TEST_IOV_ITER
2331	tristate "Test iov_iter operation" if !KUNIT_ALL_TESTS
2332	depends on KUNIT
2333	depends on MMU
2334	default KUNIT_ALL_TESTS
2335	help
2336	  Enable this to turn on testing of the operation of the I/O iterator
2337	  (iov_iter). This test is executed only once during system boot (so
2338	  affects only boot time), or at module load time.
2339
2340	  If unsure, say N.
2341
2342config KPROBES_SANITY_TEST
2343	tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2344	depends on DEBUG_KERNEL
2345	depends on KPROBES
2346	depends on KUNIT
2347	select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2348	default KUNIT_ALL_TESTS
2349	help
2350	  This option provides for testing basic kprobes functionality on
2351	  boot. Samples of kprobe and kretprobe are inserted and
2352	  verified for functionality.
2353
2354	  Say N if you are unsure.
2355
2356config FPROBE_SANITY_TEST
2357	bool "Self test for fprobe"
2358	depends on DEBUG_KERNEL
2359	depends on FPROBE
2360	depends on KUNIT=y
2361	help
2362	  This option will enable testing the fprobe when the system boot.
2363	  A series of tests are made to verify that the fprobe is functioning
2364	  properly.
2365
2366	  Say N if you are unsure.
2367
2368config BACKTRACE_SELF_TEST
2369	tristate "Self test for the backtrace code"
2370	depends on DEBUG_KERNEL
2371	help
2372	  This option provides a kernel module that can be used to test
2373	  the kernel stack backtrace code. This option is not useful
2374	  for distributions or general kernels, but only for kernel
2375	  developers working on architecture code.
2376
2377	  Note that if you want to also test saved backtraces, you will
2378	  have to enable STACKTRACE as well.
2379
2380	  Say N if you are unsure.
2381
2382config TEST_REF_TRACKER
2383	tristate "Self test for reference tracker"
2384	depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2385	select REF_TRACKER
2386	help
2387	  This option provides a kernel module performing tests
2388	  using reference tracker infrastructure.
2389
2390	  Say N if you are unsure.
2391
2392config RBTREE_TEST
2393	tristate "Red-Black tree test"
2394	depends on DEBUG_KERNEL
2395	help
2396	  A benchmark measuring the performance of the rbtree library.
2397	  Also includes rbtree invariant checks.
2398
2399config REED_SOLOMON_TEST
2400	tristate "Reed-Solomon library test"
2401	depends on DEBUG_KERNEL || m
2402	select REED_SOLOMON
2403	select REED_SOLOMON_ENC16
2404	select REED_SOLOMON_DEC16
2405	help
2406	  This option enables the self-test function of rslib at boot,
2407	  or at module load time.
2408
2409	  If unsure, say N.
2410
2411config INTERVAL_TREE_TEST
2412	tristate "Interval tree test"
2413	depends on DEBUG_KERNEL
2414	select INTERVAL_TREE
2415	help
2416	  A benchmark measuring the performance of the interval tree library
2417
2418config PERCPU_TEST
2419	tristate "Per cpu operations test"
2420	depends on m && DEBUG_KERNEL
2421	help
2422	  Enable this option to build test module which validates per-cpu
2423	  operations.
2424
2425	  If unsure, say N.
2426
2427config ATOMIC64_SELFTEST
2428	tristate "Perform an atomic64_t self-test"
2429	help
2430	  Enable this option to test the atomic64_t functions at boot or
2431	  at module load time.
2432
2433	  If unsure, say N.
2434
2435config ASYNC_RAID6_TEST
2436	tristate "Self test for hardware accelerated raid6 recovery"
2437	depends on ASYNC_RAID6_RECOV
2438	select ASYNC_MEMCPY
2439	help
2440	  This is a one-shot self test that permutes through the
2441	  recovery of all the possible two disk failure scenarios for a
2442	  N-disk array.  Recovery is performed with the asynchronous
2443	  raid6 recovery routines, and will optionally use an offload
2444	  engine if one is available.
2445
2446	  If unsure, say N.
2447
2448config TEST_HEXDUMP
2449	tristate "Test functions located in the hexdump module at runtime"
2450
2451config PRINTF_KUNIT_TEST
2452	tristate "KUnit test printf() family of functions at runtime" if !KUNIT_ALL_TESTS
2453	depends on KUNIT
2454	default KUNIT_ALL_TESTS
2455	help
2456	  Enable this option to test the printf functions at runtime.
2457
2458	  If unsure, say N.
2459
2460config SCANF_KUNIT_TEST
2461	tristate "KUnit test scanf() family of functions at runtime" if !KUNIT_ALL_TESTS
2462	depends on KUNIT
2463	default KUNIT_ALL_TESTS
2464	help
2465	  Enable this option to test the scanf functions at runtime.
2466
2467	  If unsure, say N.
2468
2469config STRING_KUNIT_TEST
2470	tristate "KUnit test string functions at runtime" if !KUNIT_ALL_TESTS
2471	depends on KUNIT
2472	default KUNIT_ALL_TESTS
2473
2474config STRING_HELPERS_KUNIT_TEST
2475	tristate "KUnit test string helpers at runtime" if !KUNIT_ALL_TESTS
2476	depends on KUNIT
2477	default KUNIT_ALL_TESTS
2478
2479config TEST_KSTRTOX
2480	tristate "Test kstrto*() family of functions at runtime"
2481
2482config TEST_BITMAP
2483	tristate "Test bitmap_*() family of functions at runtime"
2484	help
2485	  Enable this option to test the bitmap functions at boot.
2486
2487	  If unsure, say N.
2488
2489config TEST_UUID
2490	tristate "Test functions located in the uuid module at runtime"
2491
2492config TEST_XARRAY
2493	tristate "Test the XArray code at runtime"
2494
2495config TEST_MAPLE_TREE
2496	tristate "Test the Maple Tree code at runtime or module load"
2497	help
2498	  Enable this option to test the maple tree code functions at boot, or
2499	  when the module is loaded. Enable "Debug Maple Trees" will enable
2500	  more verbose output on failures.
2501
2502	  If unsure, say N.
2503
2504config TEST_RHASHTABLE
2505	tristate "Perform selftest on resizable hash table"
2506	help
2507	  Enable this option to test the rhashtable functions at boot.
2508
2509	  If unsure, say N.
2510
2511config TEST_IDA
2512	tristate "Perform selftest on IDA functions"
2513
2514config TEST_MISC_MINOR
2515	tristate "miscdevice KUnit test" if !KUNIT_ALL_TESTS
2516	depends on KUNIT
2517	default KUNIT_ALL_TESTS
2518	help
2519	  Kunit test for miscdevice API, specially its behavior in respect to
2520	  static and dynamic minor numbers.
2521
2522	  KUnit tests run during boot and output the results to the debug log
2523	  in TAP format (https://testanything.org/). Only useful for kernel devs
2524	  running the KUnit test harness, and not intended for inclusion into a
2525	  production build.
2526
2527	  For more information on KUnit and unit tests in general please refer
2528	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2529
2530	  If unsure, say N.
2531
2532config TEST_PARMAN
2533	tristate "Perform selftest on priority array manager"
2534	depends on PARMAN
2535	help
2536	  Enable this option to test priority array manager on boot
2537	  (or module load).
2538
2539	  If unsure, say N.
2540
2541config TEST_IRQ_TIMINGS
2542	bool "IRQ timings selftest"
2543	depends on IRQ_TIMINGS
2544	help
2545	  Enable this option to test the irq timings code on boot.
2546
2547	  If unsure, say N.
2548
2549config TEST_LKM
2550	tristate "Test module loading with 'hello world' module"
2551	depends on m
2552	help
2553	  This builds the "test_module" module that emits "Hello, world"
2554	  on printk when loaded. It is designed to be used for basic
2555	  evaluation of the module loading subsystem (for example when
2556	  validating module verification). It lacks any extra dependencies,
2557	  and will not normally be loaded by the system unless explicitly
2558	  requested by name.
2559
2560	  If unsure, say N.
2561
2562config TEST_BITOPS
2563	tristate "Test module for compilation of bitops operations"
2564	help
2565	  This builds the "test_bitops" module that is much like the
2566	  TEST_LKM module except that it does a basic exercise of the
2567	  set/clear_bit macros and get_count_order/long to make sure there are
2568	  no compiler warnings from C=1 sparse checker or -Wextra
2569	  compilations. It has no dependencies and doesn't run or load unless
2570	  explicitly requested by name.  for example: modprobe test_bitops.
2571
2572	  If unsure, say N.
2573
2574config TEST_VMALLOC
2575	tristate "Test module for stress/performance analysis of vmalloc allocator"
2576	default n
2577       depends on MMU
2578	depends on m
2579	help
2580	  This builds the "test_vmalloc" module that should be used for
2581	  stress and performance analysis. So, any new change for vmalloc
2582	  subsystem can be evaluated from performance and stability point
2583	  of view.
2584
2585	  If unsure, say N.
2586
2587config TEST_BPF
2588	tristate "Test BPF filter functionality"
2589	depends on m && NET
2590	help
2591	  This builds the "test_bpf" module that runs various test vectors
2592	  against the BPF interpreter or BPF JIT compiler depending on the
2593	  current setting. This is in particular useful for BPF JIT compiler
2594	  development, but also to run regression tests against changes in
2595	  the interpreter code. It also enables test stubs for eBPF maps and
2596	  verifier used by user space verifier testsuite.
2597
2598	  If unsure, say N.
2599
2600config FIND_BIT_BENCHMARK
2601	tristate "Test find_bit functions"
2602	help
2603	  This builds the "test_find_bit" module that measure find_*_bit()
2604	  functions performance.
2605
2606	  If unsure, say N.
2607
2608config TEST_FIRMWARE
2609	tristate "Test firmware loading via userspace interface"
2610	depends on FW_LOADER
2611	help
2612	  This builds the "test_firmware" module that creates a userspace
2613	  interface for testing firmware loading. This can be used to
2614	  control the triggering of firmware loading without needing an
2615	  actual firmware-using device. The contents can be rechecked by
2616	  userspace.
2617
2618	  If unsure, say N.
2619
2620config TEST_SYSCTL
2621	tristate "sysctl test driver"
2622	depends on PROC_SYSCTL
2623	help
2624	  This builds the "test_sysctl" module. This driver enables to test the
2625	  proc sysctl interfaces available to drivers safely without affecting
2626	  production knobs which might alter system functionality.
2627
2628	  If unsure, say N.
2629
2630config BITFIELD_KUNIT
2631	tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2632	depends on KUNIT
2633	default KUNIT_ALL_TESTS
2634	help
2635	  Enable this option to test the bitfield functions at boot.
2636
2637	  KUnit tests run during boot and output the results to the debug log
2638	  in TAP format (http://testanything.org/). Only useful for kernel devs
2639	  running the KUnit test harness, and not intended for inclusion into a
2640	  production build.
2641
2642	  For more information on KUnit and unit tests in general please refer
2643	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2644
2645	  If unsure, say N.
2646
2647config CHECKSUM_KUNIT
2648	tristate "KUnit test checksum functions at runtime" if !KUNIT_ALL_TESTS
2649	depends on KUNIT
2650	default KUNIT_ALL_TESTS
2651	help
2652	  Enable this option to test the checksum functions at boot.
2653
2654	  KUnit tests run during boot and output the results to the debug log
2655	  in TAP format (http://testanything.org/). Only useful for kernel devs
2656	  running the KUnit test harness, and not intended for inclusion into a
2657	  production build.
2658
2659	  For more information on KUnit and unit tests in general please refer
2660	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2661
2662	  If unsure, say N.
2663
2664config UTIL_MACROS_KUNIT
2665	tristate "KUnit test util_macros.h functions at runtime" if !KUNIT_ALL_TESTS
2666	depends on KUNIT
2667	default KUNIT_ALL_TESTS
2668	help
2669	  Enable this option to test the util_macros.h function at boot.
2670
2671	  KUnit tests run during boot and output the results to the debug log
2672	  in TAP format (http://testanything.org/). Only useful for kernel devs
2673	  running the KUnit test harness, and not intended for inclusion into a
2674	  production build.
2675
2676	  For more information on KUnit and unit tests in general please refer
2677	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2678
2679	  If unsure, say N.
2680
2681config HASH_KUNIT_TEST
2682	tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2683	depends on KUNIT
2684	default KUNIT_ALL_TESTS
2685	help
2686	  Enable this option to test the kernel's string (<linux/stringhash.h>), and
2687	  integer (<linux/hash.h>) hash functions on boot.
2688
2689	  KUnit tests run during boot and output the results to the debug log
2690	  in TAP format (https://testanything.org/). Only useful for kernel devs
2691	  running the KUnit test harness, and not intended for inclusion into a
2692	  production build.
2693
2694	  For more information on KUnit and unit tests in general please refer
2695	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2696
2697	  This is intended to help people writing architecture-specific
2698	  optimized versions. If unsure, say N.
2699
2700config RESOURCE_KUNIT_TEST
2701	tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2702	depends on KUNIT
2703	default KUNIT_ALL_TESTS
2704	select GET_FREE_REGION
2705	help
2706	  This builds the resource API unit test.
2707	  Tests the logic of API provided by resource.c and ioport.h.
2708	  For more information on KUnit and unit tests in general please refer
2709	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2710
2711	  If unsure, say N.
2712
2713config SYSCTL_KUNIT_TEST
2714	tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2715	depends on KUNIT
2716	default KUNIT_ALL_TESTS
2717	help
2718	  This builds the proc sysctl unit test, which runs on boot.
2719	  Tests the API contract and implementation correctness of sysctl.
2720	  For more information on KUnit and unit tests in general please refer
2721	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2722
2723	  If unsure, say N.
2724
2725config KFIFO_KUNIT_TEST
2726	tristate "KUnit Test for the generic kernel FIFO implementation" if !KUNIT_ALL_TESTS
2727	depends on KUNIT
2728	default KUNIT_ALL_TESTS
2729	help
2730	  This builds the generic FIFO implementation KUnit test suite.
2731	  It tests that the API and basic functionality of the kfifo type
2732	  and associated macros.
2733
2734	  For more information on KUnit and unit tests in general please refer
2735	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2736
2737	  If unsure, say N.
2738
2739config LIST_KUNIT_TEST
2740	tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2741	depends on KUNIT
2742	default KUNIT_ALL_TESTS
2743	help
2744	  This builds the linked list KUnit test suite.
2745	  It tests that the API and basic functionality of the list_head type
2746	  and associated macros.
2747
2748	  KUnit tests run during boot and output the results to the debug log
2749	  in TAP format (https://testanything.org/). Only useful for kernel devs
2750	  running the KUnit test harness, and not intended for inclusion into a
2751	  production build.
2752
2753	  For more information on KUnit and unit tests in general please refer
2754	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2755
2756	  If unsure, say N.
2757
2758config HASHTABLE_KUNIT_TEST
2759	tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS
2760	depends on KUNIT
2761	default KUNIT_ALL_TESTS
2762	help
2763	  This builds the hashtable KUnit test suite.
2764	  It tests the basic functionality of the API defined in
2765	  include/linux/hashtable.h. For more information on KUnit and
2766	  unit tests in general please refer to the KUnit documentation
2767	  in Documentation/dev-tools/kunit/.
2768
2769	  If unsure, say N.
2770
2771config LINEAR_RANGES_TEST
2772	tristate "KUnit test for linear_ranges"
2773	depends on KUNIT
2774	select LINEAR_RANGES
2775	help
2776	  This builds the linear_ranges unit test, which runs on boot.
2777	  Tests the linear_ranges logic correctness.
2778	  For more information on KUnit and unit tests in general please refer
2779	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2780
2781	  If unsure, say N.
2782
2783config CMDLINE_KUNIT_TEST
2784	tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2785	depends on KUNIT
2786	default KUNIT_ALL_TESTS
2787	help
2788	  This builds the cmdline API unit test.
2789	  Tests the logic of API provided by cmdline.c.
2790	  For more information on KUnit and unit tests in general please refer
2791	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2792
2793	  If unsure, say N.
2794
2795config BITS_TEST
2796	tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2797	depends on KUNIT
2798	default KUNIT_ALL_TESTS
2799	help
2800	  This builds the bits unit test.
2801	  Tests the logic of macros defined in bits.h.
2802	  For more information on KUnit and unit tests in general please refer
2803	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2804
2805	  If unsure, say N.
2806
2807config SLUB_KUNIT_TEST
2808	tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2809	depends on SLUB_DEBUG && KUNIT
2810	default KUNIT_ALL_TESTS
2811	help
2812	  This builds SLUB allocator unit test.
2813	  Tests SLUB cache debugging functionality.
2814	  For more information on KUnit and unit tests in general please refer
2815	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2816
2817	  If unsure, say N.
2818
2819config RATIONAL_KUNIT_TEST
2820	tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2821	depends on KUNIT && RATIONAL
2822	default KUNIT_ALL_TESTS
2823	help
2824	  This builds the rational math unit test.
2825	  For more information on KUnit and unit tests in general please refer
2826	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2827
2828	  If unsure, say N.
2829
2830config MEMCPY_KUNIT_TEST
2831	tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2832	depends on KUNIT
2833	default KUNIT_ALL_TESTS
2834	help
2835	  Builds unit tests for memcpy(), memmove(), and memset() functions.
2836	  For more information on KUnit and unit tests in general please refer
2837	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2838
2839	  If unsure, say N.
2840
2841config IS_SIGNED_TYPE_KUNIT_TEST
2842	tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2843	depends on KUNIT
2844	default KUNIT_ALL_TESTS
2845	help
2846	  Builds unit tests for the is_signed_type() macro.
2847
2848	  For more information on KUnit and unit tests in general please refer
2849	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2850
2851	  If unsure, say N.
2852
2853config OVERFLOW_KUNIT_TEST
2854	tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2855	depends on KUNIT
2856	default KUNIT_ALL_TESTS
2857	help
2858	  Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2859	  related functions.
2860
2861	  For more information on KUnit and unit tests in general please refer
2862	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2863
2864	  If unsure, say N.
2865
2866config STACKINIT_KUNIT_TEST
2867	tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2868	depends on KUNIT
2869	default KUNIT_ALL_TESTS
2870	help
2871	  Test if the kernel is zero-initializing stack variables and
2872	  padding. Coverage is controlled by compiler flags,
2873	  CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2874	  CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2875	  or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2876
2877config FORTIFY_KUNIT_TEST
2878	tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2879	depends on KUNIT
2880	default KUNIT_ALL_TESTS
2881	help
2882	  Builds unit tests for checking internals of FORTIFY_SOURCE as used
2883	  by the str*() and mem*() family of functions. For testing runtime
2884	  traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2885
2886config LONGEST_SYM_KUNIT_TEST
2887	tristate "Test the longest symbol possible" if !KUNIT_ALL_TESTS
2888	depends on KUNIT && KPROBES
2889	default KUNIT_ALL_TESTS
2890	help
2891	  Tests the longest symbol possible
2892
2893	  If unsure, say N.
2894
2895config HW_BREAKPOINT_KUNIT_TEST
2896	bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2897	depends on HAVE_HW_BREAKPOINT
2898	depends on KUNIT=y
2899	default KUNIT_ALL_TESTS
2900	help
2901	  Tests for hw_breakpoint constraints accounting.
2902
2903	  If unsure, say N.
2904
2905config CRC_KUNIT_TEST
2906	tristate "KUnit tests for CRC functions" if !KUNIT_ALL_TESTS
2907	depends on KUNIT
2908	default KUNIT_ALL_TESTS
2909	select CRC7
2910	select CRC16
2911	select CRC_T10DIF
2912	select CRC32
2913	select CRC64
2914	help
2915	  Unit tests for the CRC library functions.
2916
2917	  This is intended to help people writing architecture-specific
2918	  optimized versions.  If unsure, say N.
2919
2920config CRC_BENCHMARK
2921	bool "Benchmark for the CRC functions"
2922	depends on CRC_KUNIT_TEST
2923	help
2924	  Include benchmarks in the KUnit test suite for the CRC functions.
2925
2926config SIPHASH_KUNIT_TEST
2927	tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2928	depends on KUNIT
2929	default KUNIT_ALL_TESTS
2930	help
2931	  Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2932	  functions on boot (or module load).
2933
2934	  This is intended to help people writing architecture-specific
2935	  optimized versions.  If unsure, say N.
2936
2937config USERCOPY_KUNIT_TEST
2938	tristate "KUnit Test for user/kernel boundary protections"
2939	depends on KUNIT
2940	default KUNIT_ALL_TESTS
2941	help
2942	  This builds the "usercopy_kunit" module that runs sanity checks
2943	  on the copy_to/from_user infrastructure, making sure basic
2944	  user/kernel boundary testing is working.
2945
2946config BLACKHOLE_DEV_KUNIT_TEST
2947	tristate "Test blackhole netdev functionality" if !KUNIT_ALL_TESTS
2948	depends on NET
2949	depends on KUNIT
2950	default KUNIT_ALL_TESTS
2951	help
2952	  This builds the "blackhole_dev_kunit" module that validates the
2953	  data path through this blackhole netdev.
2954
2955	  If unsure, say N.
2956
2957config TEST_UDELAY
2958	tristate "udelay test driver"
2959	help
2960	  This builds the "udelay_test" module that helps to make sure
2961	  that udelay() is working properly.
2962
2963	  If unsure, say N.
2964
2965config TEST_STATIC_KEYS
2966	tristate "Test static keys"
2967	depends on m
2968	help
2969	  Test the static key interfaces.
2970
2971	  If unsure, say N.
2972
2973config TEST_DYNAMIC_DEBUG
2974	tristate "Test DYNAMIC_DEBUG"
2975	depends on DYNAMIC_DEBUG
2976	help
2977	  This module registers a tracer callback to count enabled
2978	  pr_debugs in a 'do_debugging' function, then alters their
2979	  enablements, calls the function, and compares counts.
2980
2981	  If unsure, say N.
2982
2983config TEST_KMOD
2984	tristate "kmod stress tester"
2985	depends on m
2986	depends on NETDEVICES && NET_CORE && INET # for TUN
2987	depends on BLOCK
2988	depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2989	select TEST_LKM
2990	select XFS_FS
2991	select TUN
2992	select BTRFS_FS
2993	help
2994	  Test the kernel's module loading mechanism: kmod. kmod implements
2995	  support to load modules using the Linux kernel's usermode helper.
2996	  This test provides a series of tests against kmod.
2997
2998	  Although technically you can either build test_kmod as a module or
2999	  into the kernel we disallow building it into the kernel since
3000	  it stress tests request_module() and this will very likely cause
3001	  some issues by taking over precious threads available from other
3002	  module load requests, ultimately this could be fatal.
3003
3004	  To run tests run:
3005
3006	  tools/testing/selftests/kmod/kmod.sh --help
3007
3008	  If unsure, say N.
3009
3010config TEST_RUNTIME
3011	bool
3012
3013config TEST_RUNTIME_MODULE
3014	bool
3015
3016config TEST_KALLSYMS
3017	tristate "module kallsyms find_symbol() test"
3018	depends on m
3019	select TEST_RUNTIME
3020	select TEST_RUNTIME_MODULE
3021	select TEST_KALLSYMS_A
3022	select TEST_KALLSYMS_B
3023	select TEST_KALLSYMS_C
3024	select TEST_KALLSYMS_D
3025	help
3026	  This allows us to stress test find_symbol() through the kallsyms
3027	  used to place symbols on the kernel ELF kallsyms and modules kallsyms
3028	  where we place kernel symbols such as exported symbols.
3029
3030	  We have four test modules:
3031
3032	  A: has KALLSYSMS_NUMSYMS exported symbols
3033	  B: uses one of A's symbols
3034	  C: adds KALLSYMS_SCALE_FACTOR * KALLSYSMS_NUMSYMS exported
3035	  D: adds 2 * the symbols than C
3036
3037	  We stress test find_symbol() through two means:
3038
3039	  1) Upon load of B it will trigger simplify_symbols() to look for the
3040	  one symbol it uses from the module A with tons of symbols. This is an
3041	  indirect way for us to have B call resolve_symbol_wait() upon module
3042	  load. This will eventually call find_symbol() which will eventually
3043	  try to find the symbols used with find_exported_symbol_in_section().
3044	  find_exported_symbol_in_section() uses bsearch() so a binary search
3045	  for each symbol. Binary search will at worst be O(log(n)) so the
3046	  larger TEST_MODULE_KALLSYSMS the worse the search.
3047
3048	  2) The selftests should load C first, before B. Upon B's load towards
3049	  the end right before we call module B's init routine we get
3050	  complete_formation() called on the module. That will first check
3051	  for duplicate symbols with the call to verify_exported_symbols().
3052	  That is when we'll force iteration on module C's insane symbol list.
3053	  Since it has 10 * KALLSYMS_NUMSYMS it means we can first test
3054	  just loading B without C. The amount of time it takes to load C Vs
3055	  B can give us an idea of the impact growth of the symbol space and
3056	  give us projection. Module A only uses one symbol from B so to allow
3057	  this scaling in module C to be proportional, if it used more symbols
3058	  then the first test would be doing more and increasing just the
3059	  search space would be slightly different. The last module, module D
3060	  will just increase the search space by twice the number of symbols in
3061	  C so to allow for full projects.
3062
3063	  tools/testing/selftests/module/find_symbol.sh
3064
3065	  The current defaults will incur a build delay of about 7 minutes
3066	  on an x86_64 with only 8 cores. Enable this only if you want to
3067	  stress test find_symbol() with thousands of symbols. At the same
3068	  time this is also useful to test building modules with thousands of
3069	  symbols, and if BTF is enabled this also stress tests adding BTF
3070	  information for each module. Currently enabling many more symbols
3071	  will segfault the build system.
3072
3073	  If unsure, say N.
3074
3075if TEST_KALLSYMS
3076
3077config TEST_KALLSYMS_A
3078	tristate
3079	depends on m
3080
3081config TEST_KALLSYMS_B
3082	tristate
3083	depends on m
3084
3085config TEST_KALLSYMS_C
3086	tristate
3087	depends on m
3088
3089config TEST_KALLSYMS_D
3090	tristate
3091	depends on m
3092
3093choice
3094	prompt "Kallsym test range"
3095	default TEST_KALLSYMS_LARGE
3096	help
3097	  Selecting something other than "Fast" will enable tests which slow
3098	  down the build and may crash your build.
3099
3100config TEST_KALLSYMS_FAST
3101	bool "Fast builds"
3102	help
3103	  You won't really be testing kallsysms, so this just helps fast builds
3104	  when allmodconfig is used..
3105
3106config TEST_KALLSYMS_LARGE
3107	bool "Enable testing kallsyms with large exports"
3108	help
3109	  This will enable larger number of symbols. This will slow down
3110	  your build considerably.
3111
3112config TEST_KALLSYMS_MAX
3113	bool "Known kallsysms limits"
3114	help
3115	  This will enable exports to the point we know we'll start crashing
3116	  builds.
3117
3118endchoice
3119
3120config TEST_KALLSYMS_NUMSYMS
3121	int "test kallsyms number of symbols"
3122	range 2 10000
3123	default 2 if TEST_KALLSYMS_FAST
3124	default 100 if TEST_KALLSYMS_LARGE
3125	default 10000 if TEST_KALLSYMS_MAX
3126	help
3127	  The number of symbols to create on TEST_KALLSYMS_A, only one of which
3128	  module TEST_KALLSYMS_B will use. This also will be used
3129	  for how many symbols TEST_KALLSYMS_C will have, scaled up by
3130	  TEST_KALLSYMS_SCALE_FACTOR. Note that setting this to 10,000 will
3131	  trigger a segfault today, don't use anything close to it unless
3132	  you are aware that this should not be used for automated build tests.
3133
3134config TEST_KALLSYMS_SCALE_FACTOR
3135	int "test kallsyms scale factor"
3136	default 8
3137	help
3138	  How many more unusued symbols will TEST_KALLSYSMS_C have than
3139	  TEST_KALLSYMS_A. If 8, then module C will have 8 * syms
3140	  than module A. Then TEST_KALLSYMS_D will have double the amount
3141	  of symbols than C so to allow projections.
3142
3143endif # TEST_KALLSYMS
3144
3145config TEST_DEBUG_VIRTUAL
3146	tristate "Test CONFIG_DEBUG_VIRTUAL feature"
3147	depends on DEBUG_VIRTUAL
3148	help
3149	  Test the kernel's ability to detect incorrect calls to
3150	  virt_to_phys() done against the non-linear part of the
3151	  kernel's virtual address map.
3152
3153	  If unsure, say N.
3154
3155config TEST_MEMCAT_P
3156	tristate "Test memcat_p() helper function"
3157	help
3158	  Test the memcat_p() helper for correctly merging two
3159	  pointer arrays together.
3160
3161	  If unsure, say N.
3162
3163config TEST_OBJAGG
3164	tristate "Perform selftest on object aggreration manager"
3165	default n
3166	depends on OBJAGG
3167	help
3168	  Enable this option to test object aggregation manager on boot
3169	  (or module load).
3170
3171config TEST_MEMINIT
3172	tristate "Test heap/page initialization"
3173	help
3174	  Test if the kernel is zero-initializing heap and page allocations.
3175	  This can be useful to test init_on_alloc and init_on_free features.
3176
3177	  If unsure, say N.
3178
3179config TEST_HMM
3180	tristate "Test HMM (Heterogeneous Memory Management)"
3181	depends on TRANSPARENT_HUGEPAGE
3182	depends on DEVICE_PRIVATE
3183	select HMM_MIRROR
3184	select MMU_NOTIFIER
3185	help
3186	  This is a pseudo device driver solely for testing HMM.
3187	  Say M here if you want to build the HMM test module.
3188	  Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
3189
3190	  If unsure, say N.
3191
3192config TEST_FREE_PAGES
3193	tristate "Test freeing pages"
3194	help
3195	  Test that a memory leak does not occur due to a race between
3196	  freeing a block of pages and a speculative page reference.
3197	  Loading this module is safe if your kernel has the bug fixed.
3198	  If the bug is not fixed, it will leak gigabytes of memory and
3199	  probably OOM your system.
3200
3201config TEST_FPU
3202	tristate "Test floating point operations in kernel space"
3203	depends on ARCH_HAS_KERNEL_FPU_SUPPORT && !KCOV_INSTRUMENT_ALL
3204	help
3205	  Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
3206	  which will trigger a sequence of floating point operations. This is used
3207	  for self-testing floating point control register setting in
3208	  kernel_fpu_begin().
3209
3210	  If unsure, say N.
3211
3212config TEST_CLOCKSOURCE_WATCHDOG
3213	tristate "Test clocksource watchdog in kernel space"
3214	depends on CLOCKSOURCE_WATCHDOG
3215	help
3216	  Enable this option to create a kernel module that will trigger
3217	  a test of the clocksource watchdog.  This module may be loaded
3218	  via modprobe or insmod in which case it will run upon being
3219	  loaded, or it may be built in, in which case it will run
3220	  shortly after boot.
3221
3222	  If unsure, say N.
3223
3224config TEST_OBJPOOL
3225	tristate "Test module for correctness and stress of objpool"
3226	default n
3227	depends on m && DEBUG_KERNEL
3228	help
3229	  This builds the "test_objpool" module that should be used for
3230	  correctness verification and concurrent testings of objects
3231	  allocation and reclamation.
3232
3233	  If unsure, say N.
3234
3235config INT_POW_KUNIT_TEST
3236	tristate "Integer exponentiation (int_pow) test" if !KUNIT_ALL_TESTS
3237	depends on KUNIT
3238	default KUNIT_ALL_TESTS
3239	help
3240	  This option enables the KUnit test suite for the int_pow function,
3241	  which performs integer exponentiation. The test suite is designed to
3242	  verify that the implementation of int_pow correctly computes the power
3243	  of a given base raised to a given exponent.
3244
3245	  Enabling this option will include tests that check various scenarios
3246	  and edge cases to ensure the accuracy and reliability of the exponentiation
3247	  function.
3248
3249	  If unsure, say N
3250
3251config INT_SQRT_KUNIT_TEST
3252	tristate "Integer square root test" if !KUNIT_ALL_TESTS
3253	depends on KUNIT
3254	default KUNIT_ALL_TESTS
3255	help
3256	  This option enables the KUnit test suite for the int_sqrt() function,
3257	  which performs square root calculation. The test suite checks
3258	  various scenarios, including edge cases, to ensure correctness.
3259
3260	  Enabling this option will include tests that check various scenarios
3261	  and edge cases to ensure the accuracy and reliability of the square root
3262	  function.
3263
3264	  If unsure, say N
3265
3266config INT_LOG_KUNIT_TEST
3267        tristate "Integer log (int_log) test" if !KUNIT_ALL_TESTS
3268        depends on KUNIT
3269        default KUNIT_ALL_TESTS
3270        help
3271          This option enables the KUnit test suite for the int_log library, which
3272          provides two functions to compute the integer logarithm in base 2 and
3273          base 10, called respectively as intlog2 and intlog10.
3274
3275          If unsure, say N
3276
3277config GCD_KUNIT_TEST
3278	tristate "Greatest common divisor test" if !KUNIT_ALL_TESTS
3279	depends on KUNIT
3280	default KUNIT_ALL_TESTS
3281	help
3282	  This option enables the KUnit test suite for the gcd() function,
3283	  which computes the greatest common divisor of two numbers.
3284
3285	  This test suite verifies the correctness of gcd() across various
3286	  scenarios, including edge cases.
3287
3288	  If unsure, say N
3289
3290config PRIME_NUMBERS_KUNIT_TEST
3291	tristate "Prime number generator test" if !KUNIT_ALL_TESTS
3292	depends on KUNIT
3293	select PRIME_NUMBERS
3294	default KUNIT_ALL_TESTS
3295	help
3296	  This option enables the KUnit test suite for the {is,next}_prime_number
3297	  functions.
3298
3299	  Enabling this option will include tests that compare the prime number
3300	  generator functions against a brute force implementation.
3301
3302	  If unsure, say N
3303
3304endif # RUNTIME_TESTING_MENU
3305
3306config ARCH_USE_MEMTEST
3307	bool
3308	help
3309	  An architecture should select this when it uses early_memtest()
3310	  during boot process.
3311
3312config MEMTEST
3313	bool "Memtest"
3314	depends on ARCH_USE_MEMTEST
3315	help
3316	  This option adds a kernel parameter 'memtest', which allows memtest
3317	  to be set and executed.
3318	        memtest=0, mean disabled; -- default
3319	        memtest=1, mean do 1 test pattern;
3320	        ...
3321	        memtest=17, mean do 17 test patterns.
3322	  If you are unsure how to answer this question, answer N.
3323
3324
3325
3326config HYPERV_TESTING
3327	bool "Microsoft Hyper-V driver testing"
3328	default n
3329	depends on HYPERV && DEBUG_FS
3330	help
3331	  Select this option to enable Hyper-V vmbus testing.
3332
3333endmenu # "Kernel Testing and Coverage"
3334
3335menu "Rust hacking"
3336
3337config RUST_DEBUG_ASSERTIONS
3338	bool "Debug assertions"
3339	depends on RUST
3340	help
3341	  Enables rustc's `-Cdebug-assertions` codegen option.
3342
3343	  This flag lets you turn `cfg(debug_assertions)` conditional
3344	  compilation on or off. This can be used to enable extra debugging
3345	  code in development but not in production. For example, it controls
3346	  the behavior of the standard library's `debug_assert!` macro.
3347
3348	  Note that this will apply to all Rust code, including `core`.
3349
3350	  If unsure, say N.
3351
3352config RUST_OVERFLOW_CHECKS
3353	bool "Overflow checks"
3354	default y
3355	depends on RUST
3356	help
3357	  Enables rustc's `-Coverflow-checks` codegen option.
3358
3359	  This flag allows you to control the behavior of runtime integer
3360	  overflow. When overflow-checks are enabled, a Rust panic will occur
3361	  on overflow.
3362
3363	  Note that this will apply to all Rust code, including `core`.
3364
3365	  If unsure, say Y.
3366
3367config RUST_BUILD_ASSERT_ALLOW
3368	bool "Allow unoptimized build-time assertions"
3369	depends on RUST
3370	help
3371	  Controls how `build_error!` and `build_assert!` are handled during the build.
3372
3373	  If calls to them exist in the binary, it may indicate a violated invariant
3374	  or that the optimizer failed to verify the invariant during compilation.
3375
3376	  This should not happen, thus by default the build is aborted. However,
3377	  as an escape hatch, you can choose Y here to ignore them during build
3378	  and let the check be carried at runtime (with `panic!` being called if
3379	  the check fails).
3380
3381	  If unsure, say N.
3382
3383config RUST_KERNEL_DOCTESTS
3384	bool "Doctests for the `kernel` crate" if !KUNIT_ALL_TESTS
3385	depends on RUST && KUNIT=y
3386	default KUNIT_ALL_TESTS
3387	help
3388	  This builds the documentation tests of the `kernel` crate
3389	  as KUnit tests.
3390
3391	  For more information on KUnit and unit tests in general,
3392	  please refer to the KUnit documentation in Documentation/dev-tools/kunit/.
3393
3394	  If unsure, say N.
3395
3396endmenu # "Rust"
3397
3398endmenu # Kernel hacking
3399