xref: /linux/lib/Kconfig.debug (revision 25929dae28f528d7d74992edabd38bf3c374e485)
1# SPDX-License-Identifier: GPL-2.0-only
2menu "Kernel hacking"
3
4menu "printk and dmesg options"
5
6config PRINTK_TIME
7	bool "Show timing information on printks"
8	depends on PRINTK
9	help
10	  Selecting this option causes time stamps of the printk()
11	  messages to be added to the output of the syslog() system
12	  call and at the console.
13
14	  The timestamp is always recorded internally, and exported
15	  to /dev/kmsg. This flag just specifies if the timestamp should
16	  be included, not that the timestamp is recorded.
17
18	  The behavior is also controlled by the kernel command line
19	  parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
20
21config PRINTK_CALLER
22	bool "Show caller information on printks"
23	depends on PRINTK
24	help
25	  Selecting this option causes printk() to add a caller "thread id" (if
26	  in task context) or a caller "processor id" (if not in task context)
27	  to every message.
28
29	  This option is intended for environments where multiple threads
30	  concurrently call printk() for many times, for it is difficult to
31	  interpret without knowing where these lines (or sometimes individual
32	  line which was divided into multiple lines due to race) came from.
33
34	  Since toggling after boot makes the code racy, currently there is
35	  no option to enable/disable at the kernel command line parameter or
36	  sysfs interface.
37
38config STACKTRACE_BUILD_ID
39	bool "Show build ID information in stacktraces"
40	depends on PRINTK
41	help
42	  Selecting this option adds build ID information for symbols in
43	  stacktraces printed with the printk format '%p[SR]b'.
44
45	  This option is intended for distros where debuginfo is not easily
46	  accessible but can be downloaded given the build ID of the vmlinux or
47	  kernel module where the function is located.
48
49config CONSOLE_LOGLEVEL_DEFAULT
50	int "Default console loglevel (1-15)"
51	range 1 15
52	default "7"
53	help
54	  Default loglevel to determine what will be printed on the console.
55
56	  Setting a default here is equivalent to passing in loglevel=<x> in
57	  the kernel bootargs. loglevel=<x> continues to override whatever
58	  value is specified here as well.
59
60	  Note: This does not affect the log level of un-prefixed printk()
61	  usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
62	  option.
63
64config CONSOLE_LOGLEVEL_QUIET
65	int "quiet console loglevel (1-15)"
66	range 1 15
67	default "4"
68	help
69	  loglevel to use when "quiet" is passed on the kernel commandline.
70
71	  When "quiet" is passed on the kernel commandline this loglevel
72	  will be used as the loglevel. IOW passing "quiet" will be the
73	  equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
74
75config MESSAGE_LOGLEVEL_DEFAULT
76	int "Default message log level (1-7)"
77	range 1 7
78	default "4"
79	help
80	  Default log level for printk statements with no specified priority.
81
82	  This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
83	  that are auditing their logs closely may want to set it to a lower
84	  priority.
85
86	  Note: This does not affect what message level gets printed on the console
87	  by default. To change that, use loglevel=<x> in the kernel bootargs,
88	  or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
89
90config BOOT_PRINTK_DELAY
91	bool "Delay each boot printk message by N milliseconds"
92	depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
93	help
94	  This build option allows you to read kernel boot messages
95	  by inserting a short delay after each one.  The delay is
96	  specified in milliseconds on the kernel command line,
97	  using "boot_delay=N".
98
99	  It is likely that you would also need to use "lpj=M" to preset
100	  the "loops per jiffy" value.
101	  See a previous boot log for the "lpj" value to use for your
102	  system, and then set "lpj=M" before setting "boot_delay=N".
103	  NOTE:  Using this option may adversely affect SMP systems.
104	  I.e., processors other than the first one may not boot up.
105	  BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
106	  what it believes to be lockup conditions.
107
108config DYNAMIC_DEBUG
109	bool "Enable dynamic printk() support"
110	default n
111	depends on PRINTK
112	depends on (DEBUG_FS || PROC_FS)
113	select DYNAMIC_DEBUG_CORE
114	help
115
116	  Compiles debug level messages into the kernel, which would not
117	  otherwise be available at runtime. These messages can then be
118	  enabled/disabled based on various levels of scope - per source file,
119	  function, module, format string, and line number. This mechanism
120	  implicitly compiles in all pr_debug() and dev_dbg() calls, which
121	  enlarges the kernel text size by about 2%.
122
123	  If a source file is compiled with DEBUG flag set, any
124	  pr_debug() calls in it are enabled by default, but can be
125	  disabled at runtime as below.  Note that DEBUG flag is
126	  turned on by many CONFIG_*DEBUG* options.
127
128	  Usage:
129
130	  Dynamic debugging is controlled via the 'dynamic_debug/control' file,
131	  which is contained in the 'debugfs' filesystem or procfs.
132	  Thus, the debugfs or procfs filesystem must first be mounted before
133	  making use of this feature.
134	  We refer the control file as: <debugfs>/dynamic_debug/control. This
135	  file contains a list of the debug statements that can be enabled. The
136	  format for each line of the file is:
137
138		filename:lineno [module]function flags format
139
140	  filename : source file of the debug statement
141	  lineno : line number of the debug statement
142	  module : module that contains the debug statement
143	  function : function that contains the debug statement
144	  flags : '=p' means the line is turned 'on' for printing
145	  format : the format used for the debug statement
146
147	  From a live system:
148
149		nullarbor:~ # cat <debugfs>/dynamic_debug/control
150		# filename:lineno [module]function flags format
151		fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
152		fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
153		fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
154
155	  Example usage:
156
157		// enable the message at line 1603 of file svcsock.c
158		nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
159						<debugfs>/dynamic_debug/control
160
161		// enable all the messages in file svcsock.c
162		nullarbor:~ # echo -n 'file svcsock.c +p' >
163						<debugfs>/dynamic_debug/control
164
165		// enable all the messages in the NFS server module
166		nullarbor:~ # echo -n 'module nfsd +p' >
167						<debugfs>/dynamic_debug/control
168
169		// enable all 12 messages in the function svc_process()
170		nullarbor:~ # echo -n 'func svc_process +p' >
171						<debugfs>/dynamic_debug/control
172
173		// disable all 12 messages in the function svc_process()
174		nullarbor:~ # echo -n 'func svc_process -p' >
175						<debugfs>/dynamic_debug/control
176
177	  See Documentation/admin-guide/dynamic-debug-howto.rst for additional
178	  information.
179
180config DYNAMIC_DEBUG_CORE
181	bool "Enable core function of dynamic debug support"
182	depends on PRINTK
183	depends on (DEBUG_FS || PROC_FS)
184	help
185	  Enable core functional support of dynamic debug. It is useful
186	  when you want to tie dynamic debug to your kernel modules with
187	  DYNAMIC_DEBUG_MODULE defined for each of them, especially for
188	  the case of embedded system where the kernel image size is
189	  sensitive for people.
190
191config SYMBOLIC_ERRNAME
192	bool "Support symbolic error names in printf"
193	default y if PRINTK
194	help
195	  If you say Y here, the kernel's printf implementation will
196	  be able to print symbolic error names such as ENOSPC instead
197	  of the number 28. It makes the kernel image slightly larger
198	  (about 3KB), but can make the kernel logs easier to read.
199
200config DEBUG_BUGVERBOSE
201	bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
202	depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
203	default y
204	help
205	  Say Y here to make BUG() panics output the file name and line number
206	  of the BUG call as well as the EIP and oops trace.  This aids
207	  debugging but costs about 70-100K of memory.
208
209config DEBUG_BUGVERBOSE_DETAILED
210	bool "Verbose WARN_ON_ONCE() reporting (adds 100K)" if DEBUG_BUGVERBOSE
211	help
212	  Say Y here to make WARN_ON_ONCE() output the condition string of the
213	  warning, in addition to the file name and line number.
214	  This helps debugging, but costs about 100K of memory.
215
216	  Say N if unsure.
217
218
219endmenu # "printk and dmesg options"
220
221config DEBUG_KERNEL
222	bool "Kernel debugging"
223	help
224	  Say Y here if you are developing drivers or trying to debug and
225	  identify kernel problems.
226
227config DEBUG_MISC
228	bool "Miscellaneous debug code"
229	default DEBUG_KERNEL
230	depends on DEBUG_KERNEL
231	help
232	  Say Y here if you need to enable miscellaneous debug code that should
233	  be under a more specific debug option but isn't.
234
235menu "Compile-time checks and compiler options"
236
237config DEBUG_INFO
238	bool
239	help
240	  A kernel debug info option other than "None" has been selected
241	  in the "Debug information" choice below, indicating that debug
242	  information will be generated for build targets.
243
244# Clang generates .uleb128 with label differences for DWARF v5, a feature that
245# older binutils ports do not support when utilizing RISC-V style linker
246# relaxation: https://sourceware.org/bugzilla/show_bug.cgi?id=27215
247config AS_HAS_NON_CONST_ULEB128
248	def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:)
249
250choice
251	prompt "Debug information"
252	depends on DEBUG_KERNEL
253	help
254	  Selecting something other than "None" results in a kernel image
255	  that will include debugging info resulting in a larger kernel image.
256	  This adds debug symbols to the kernel and modules (gcc -g), and
257	  is needed if you intend to use kernel crashdump or binary object
258	  tools like crash, kgdb, LKCD, gdb, etc on the kernel.
259
260	  Choose which version of DWARF debug info to emit. If unsure,
261	  select "Toolchain default".
262
263config DEBUG_INFO_NONE
264	bool "Disable debug information"
265	help
266	  Do not build the kernel with debugging information, which will
267	  result in a faster and smaller build.
268
269config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
270	bool "Rely on the toolchain's implicit default DWARF version"
271	select DEBUG_INFO
272	depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128)
273	help
274	  The implicit default version of DWARF debug info produced by a
275	  toolchain changes over time.
276
277	  This can break consumers of the debug info that haven't upgraded to
278	  support newer revisions, and prevent testing newer versions, but
279	  those should be less common scenarios.
280
281config DEBUG_INFO_DWARF4
282	bool "Generate DWARF Version 4 debuginfo"
283	select DEBUG_INFO
284	depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)
285	help
286	  Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2
287	  if using clang without clang's integrated assembler, and gdb 7.0+.
288
289	  If you have consumers of DWARF debug info that are not ready for
290	  newer revisions of DWARF, you may wish to choose this or have your
291	  config select this.
292
293config DEBUG_INFO_DWARF5
294	bool "Generate DWARF Version 5 debuginfo"
295	select DEBUG_INFO
296	depends on !ARCH_HAS_BROKEN_DWARF5
297	depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128)
298	help
299	  Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
300	  5.0+ accepts the -gdwarf-5 flag but only had partial support for some
301	  draft features until 7.0), and gdb 8.0+.
302
303	  Changes to the structure of debug info in Version 5 allow for around
304	  15-18% savings in resulting image and debug info section sizes as
305	  compared to DWARF Version 4. DWARF Version 5 standardizes previous
306	  extensions such as accelerators for symbol indexing and the format
307	  for fission (.dwo/.dwp) files. Users may not want to select this
308	  config if they rely on tooling that has not yet been updated to
309	  support DWARF Version 5.
310
311endchoice # "Debug information"
312
313if DEBUG_INFO
314
315config DEBUG_INFO_REDUCED
316	bool "Reduce debugging information"
317	help
318	  If you say Y here gcc is instructed to generate less debugging
319	  information for structure types. This means that tools that
320	  need full debugging information (like kgdb or systemtap) won't
321	  be happy. But if you merely need debugging information to
322	  resolve line numbers there is no loss. Advantage is that
323	  build directory object sizes shrink dramatically over a full
324	  DEBUG_INFO build and compile times are reduced too.
325	  Only works with newer gcc versions.
326
327choice
328	prompt "Compressed Debug information"
329	help
330	  Compress the resulting debug info. Results in smaller debug info sections,
331	  but requires that consumers are able to decompress the results.
332
333	  If unsure, choose DEBUG_INFO_COMPRESSED_NONE.
334
335config DEBUG_INFO_COMPRESSED_NONE
336	bool "Don't compress debug information"
337	help
338	  Don't compress debug info sections.
339
340config DEBUG_INFO_COMPRESSED_ZLIB
341	bool "Compress debugging information with zlib"
342	depends on $(cc-option,-gz=zlib)
343	depends on $(ld-option,--compress-debug-sections=zlib)
344	help
345	  Compress the debug information using zlib.
346
347	  Users of dpkg-deb via debian/rules may find an increase in
348	  size of their debug .deb packages with this config set, due to the
349	  debug info being compressed with zlib, then the object files being
350	  recompressed with a different compression scheme. But this is still
351	  preferable to setting KDEB_COMPRESS or DPKG_DEB_COMPRESSOR_TYPE to
352	  "none" which would be even larger.
353
354config DEBUG_INFO_COMPRESSED_ZSTD
355	bool "Compress debugging information with zstd"
356	depends on $(cc-option,-gz=zstd)
357	depends on $(ld-option,--compress-debug-sections=zstd)
358	help
359	  Compress the debug information using zstd.  This may provide better
360	  compression than zlib, for about the same time costs, but requires newer
361	  toolchain support.  Requires GCC 13.0+ or Clang 16.0+, binutils 2.40+, and
362	  zstd.
363
364endchoice # "Compressed Debug information"
365
366config DEBUG_INFO_SPLIT
367	bool "Produce split debuginfo in .dwo files"
368	depends on $(cc-option,-gsplit-dwarf)
369	# RISC-V linker relaxation + -gsplit-dwarf has issues with LLVM and GCC
370	# prior to 12.x:
371	# https://github.com/llvm/llvm-project/issues/56642
372	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99090
373	depends on !RISCV || GCC_VERSION >= 120000
374	help
375	  Generate debug info into separate .dwo files. This significantly
376	  reduces the build directory size for builds with DEBUG_INFO,
377	  because it stores the information only once on disk in .dwo
378	  files instead of multiple times in object files and executables.
379	  In addition the debug information is also compressed.
380
381	  Requires recent gcc (4.7+) and recent gdb/binutils.
382	  Any tool that packages or reads debug information would need
383	  to know about the .dwo files and include them.
384	  Incompatible with older versions of ccache.
385
386config DEBUG_INFO_BTF
387	bool "Generate BTF type information"
388	depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
389	depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
390	depends on BPF_SYSCALL
391	depends on PAHOLE_VERSION >= 116
392	depends on DEBUG_INFO_DWARF4 || PAHOLE_VERSION >= 121
393	# pahole uses elfutils, which does not have support for Hexagon relocations
394	depends on !HEXAGON
395	help
396	  Generate deduplicated BTF type information from DWARF debug info.
397	  Turning this on requires pahole v1.16 or later (v1.21 or later to
398	  support DWARF 5), which will convert DWARF type info into equivalent
399	  deduplicated BTF type info.
400
401config PAHOLE_HAS_SPLIT_BTF
402	def_bool PAHOLE_VERSION >= 119
403
404config PAHOLE_HAS_BTF_TAG
405	def_bool PAHOLE_VERSION >= 123
406	depends on CC_IS_CLANG
407	help
408	  Decide whether pahole emits btf_tag attributes (btf_type_tag and
409	  btf_decl_tag) or not. Currently only clang compiler implements
410	  these attributes, so make the config depend on CC_IS_CLANG.
411
412config PAHOLE_HAS_LANG_EXCLUDE
413	def_bool PAHOLE_VERSION >= 124
414	help
415	  Support for the --lang_exclude flag which makes pahole exclude
416	  compilation units from the supplied language. Used in Kbuild to
417	  omit Rust CUs which are not supported in version 1.24 of pahole,
418	  otherwise it would emit malformed kernel and module binaries when
419	  using DEBUG_INFO_BTF_MODULES.
420
421config DEBUG_INFO_BTF_MODULES
422	bool "Generate BTF type information for kernel modules"
423	default y
424	depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
425	help
426	  Generate compact split BTF type information for kernel modules.
427
428config MODULE_ALLOW_BTF_MISMATCH
429	bool "Allow loading modules with non-matching BTF type info"
430	depends on DEBUG_INFO_BTF_MODULES
431	help
432	  For modules whose split BTF does not match vmlinux, load without
433	  BTF rather than refusing to load. The default behavior with
434	  module BTF enabled is to reject modules with such mismatches;
435	  this option will still load module BTF where possible but ignore
436	  it when a mismatch is found.
437
438config GDB_SCRIPTS
439	bool "Provide GDB scripts for kernel debugging"
440	help
441	  This creates the required links to GDB helper scripts in the
442	  build directory. If you load vmlinux into gdb, the helper
443	  scripts will be automatically imported by gdb as well, and
444	  additional functions are available to analyze a Linux kernel
445	  instance. See Documentation/process/debugging/gdb-kernel-debugging.rst
446	  for further details.
447
448endif # DEBUG_INFO
449
450config FRAME_WARN
451	int "Warn for stack frames larger than"
452	range 0 8192
453	default 0 if KMSAN
454	default 2048 if GCC_PLUGIN_LATENT_ENTROPY
455	default 2048 if PARISC
456	default 1536 if (!64BIT && XTENSA)
457	default 1280 if !64BIT
458	default 2048 if 64BIT
459	help
460	  Tell the compiler to warn at build time for stack frames larger than this.
461	  Setting this too low will cause a lot of warnings.
462	  Setting it to 0 disables the warning.
463
464config STRIP_ASM_SYMS
465	bool "Strip assembler-generated symbols during link"
466	default n
467	help
468	  Strip internal assembler-generated symbols during a link (symbols
469	  that look like '.Lxxx') so they don't pollute the output of
470	  get_wchan() and suchlike.
471
472config READABLE_ASM
473	bool "Generate readable assembler code"
474	depends on DEBUG_KERNEL
475	depends on CC_IS_GCC
476	help
477	  Disable some compiler optimizations that tend to generate human unreadable
478	  assembler output. This may make the kernel slightly slower, but it helps
479	  to keep kernel developers who have to stare a lot at assembler listings
480	  sane.
481
482config HEADERS_INSTALL
483	bool "Install uapi headers to usr/include"
484	help
485	  This option will install uapi headers (headers exported to user-space)
486	  into the usr/include directory for use during the kernel build.
487	  This is unneeded for building the kernel itself, but needed for some
488	  user-space program samples. It is also needed by some features such
489	  as uapi header sanity checks.
490
491config DEBUG_SECTION_MISMATCH
492	bool "Enable full Section mismatch analysis"
493	depends on CC_IS_GCC
494	help
495	  The section mismatch analysis checks if there are illegal references
496	  from one section to another. During linktime or runtime, some
497	  sections are dropped; any use of code/data previously in these
498	  sections would most likely result in an oops.
499
500	  In the code, functions and variables are annotated with __init,
501	  __initdata, and so on (see the full list in include/linux/init.h).
502	  This directs the toolchain to place code/data in specific sections.
503
504	  The section mismatch analysis is always performed after a full
505	  kernel build, and enabling this option causes the option
506	  -fno-inline-functions-called-once to be added to gcc commands.
507
508	  However, when inlining a function annotated with __init in
509	  a non-init function, we would lose the section information and thus
510	  the analysis would not catch the illegal reference.  This option
511	  tells gcc to inline less (but it does result in a larger kernel).
512
513config SECTION_MISMATCH_WARN_ONLY
514	bool "Make section mismatch errors non-fatal"
515	default y
516	help
517	  If you say N here, the build process will fail if there are any
518	  section mismatch, instead of just throwing warnings.
519
520	  If unsure, say Y.
521
522config DEBUG_FORCE_FUNCTION_ALIGN_64B
523	bool "Force all function address 64B aligned"
524	depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC || RISCV || S390)
525	select FUNCTION_ALIGNMENT_64B
526	help
527	  There are cases that a commit from one domain changes the function
528	  address alignment of other domains, and cause magic performance
529	  bump (regression or improvement). Enable this option will help to
530	  verify if the bump is caused by function alignment changes, while
531	  it will slightly increase the kernel size and affect icache usage.
532
533	  It is mainly for debug and performance tuning use.
534
535#
536# Select this config option from the architecture Kconfig, if it
537# is preferred to always offer frame pointers as a config
538# option on the architecture (regardless of KERNEL_DEBUG):
539#
540config ARCH_WANT_FRAME_POINTERS
541	bool
542
543config FRAME_POINTER
544	bool "Compile the kernel with frame pointers"
545	depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
546	default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
547	help
548	  If you say Y here the resulting kernel image will be slightly
549	  larger and slower, but it gives very useful debugging information
550	  in case of kernel bugs. (precise oopses/stacktraces/warnings)
551
552config OBJTOOL
553	bool
554
555config OBJTOOL_WERROR
556	bool "Upgrade objtool warnings to errors"
557	depends on OBJTOOL && !COMPILE_TEST
558	help
559	  Fail the build on objtool warnings.
560
561	  Objtool warnings can indicate kernel instability, including boot
562	  failures.  This option is highly recommended.
563
564	  If unsure, say Y.
565
566config STACK_VALIDATION
567	bool "Compile-time stack metadata validation"
568	depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
569	select OBJTOOL
570	default n
571	help
572	  Validate frame pointer rules at compile-time.  This helps ensure that
573	  runtime stack traces are more reliable.
574
575	  For more information, see
576	  tools/objtool/Documentation/objtool.txt.
577
578config NOINSTR_VALIDATION
579	bool
580	depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
581	select OBJTOOL
582	default y
583
584config VMLINUX_MAP
585	bool "Generate vmlinux.map file when linking"
586	depends on EXPERT
587	help
588	  Selecting this option will pass "-Map=vmlinux.map" to ld
589	  when linking vmlinux. That file can be useful for verifying
590	  and debugging magic section games, and for seeing which
591	  pieces of code get eliminated with
592	  CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
593
594config BUILTIN_MODULE_RANGES
595	bool "Generate address range information for builtin modules"
596	depends on !LTO
597	depends on VMLINUX_MAP
598	help
599	 When modules are built into the kernel, there will be no module name
600	 associated with its symbols in /proc/kallsyms.  Tracers may want to
601	 identify symbols by module name and symbol name regardless of whether
602	 the module is configured as loadable or not.
603
604	 This option generates modules.builtin.ranges in the build tree with
605	 offset ranges (per ELF section) for the module(s) they belong to.
606	 It also records an anchor symbol to determine the load address of the
607	 section.
608
609config DEBUG_FORCE_WEAK_PER_CPU
610	bool "Force weak per-cpu definitions"
611	depends on DEBUG_KERNEL
612	help
613	  s390 and alpha require percpu variables in modules to be
614	  defined weak to work around addressing range issue which
615	  puts the following two restrictions on percpu variable
616	  definitions.
617
618	  1. percpu symbols must be unique whether static or not
619	  2. percpu variables can't be defined inside a function
620
621	  To ensure that generic code follows the above rules, this
622	  option forces all percpu variables to be defined as weak.
623
624endmenu # "Compiler options"
625
626menu "Generic Kernel Debugging Instruments"
627
628config MAGIC_SYSRQ
629	bool "Magic SysRq key"
630	depends on !UML
631	help
632	  If you say Y here, you will have some control over the system even
633	  if the system crashes for example during kernel debugging (e.g., you
634	  will be able to flush the buffer cache to disk, reboot the system
635	  immediately or dump some status information). This is accomplished
636	  by pressing various keys while holding SysRq (Alt+PrintScreen). It
637	  also works on a serial console (on PC hardware at least), if you
638	  send a BREAK and then within 5 seconds a command keypress. The
639	  keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
640	  Don't say Y unless you really know what this hack does.
641
642config MAGIC_SYSRQ_DEFAULT_ENABLE
643	hex "Enable magic SysRq key functions by default"
644	depends on MAGIC_SYSRQ
645	default 0x1
646	help
647	  Specifies which SysRq key functions are enabled by default.
648	  This may be set to 1 or 0 to enable or disable them all, or
649	  to a bitmask as described in Documentation/admin-guide/sysrq.rst.
650
651config MAGIC_SYSRQ_SERIAL
652	bool "Enable magic SysRq key over serial"
653	depends on MAGIC_SYSRQ
654	default y
655	help
656	  Many embedded boards have a disconnected TTL level serial which can
657	  generate some garbage that can lead to spurious false sysrq detects.
658	  This option allows you to decide whether you want to enable the
659	  magic SysRq key.
660
661config MAGIC_SYSRQ_SERIAL_SEQUENCE
662	string "Char sequence that enables magic SysRq over serial"
663	depends on MAGIC_SYSRQ_SERIAL
664	default ""
665	help
666	  Specifies a sequence of characters that can follow BREAK to enable
667	  SysRq on a serial console.
668
669	  If unsure, leave an empty string and the option will not be enabled.
670
671config DEBUG_FS
672	bool "Debug Filesystem"
673	help
674	  debugfs is a virtual file system that kernel developers use to put
675	  debugging files into.  Enable this option to be able to read and
676	  write to these files.
677
678	  For detailed documentation on the debugfs API, see
679	  Documentation/filesystems/.
680
681	  If unsure, say N.
682
683choice
684	prompt "Debugfs default access"
685	depends on DEBUG_FS
686	default DEBUG_FS_ALLOW_ALL
687	help
688	  This selects the default access restrictions for debugfs.
689	  It can be overridden with kernel command line option
690	  debugfs=[on,off]. The restrictions apply for API access
691	  and filesystem registration.
692
693config DEBUG_FS_ALLOW_ALL
694	bool "Access normal"
695	help
696	  No restrictions apply. Both API and filesystem registration
697	  is on. This is the normal default operation.
698
699config DEBUG_FS_ALLOW_NONE
700	bool "No access"
701	help
702	  Access is off. Clients get -PERM when trying to create nodes in
703	  debugfs tree and debugfs is not registered as a filesystem.
704	  Client can then back-off or continue without debugfs access.
705
706endchoice
707
708source "lib/Kconfig.kgdb"
709source "lib/Kconfig.ubsan"
710source "lib/Kconfig.kcsan"
711
712endmenu
713
714menu "Networking Debugging"
715
716source "net/Kconfig.debug"
717
718endmenu # "Networking Debugging"
719
720menu "Memory Debugging"
721
722source "mm/Kconfig.debug"
723
724config DEBUG_OBJECTS
725	bool "Debug object operations"
726	depends on DEBUG_KERNEL
727	help
728	  If you say Y here, additional code will be inserted into the
729	  kernel to track the life time of various objects and validate
730	  the operations on those objects.
731
732config DEBUG_OBJECTS_SELFTEST
733	bool "Debug objects selftest"
734	depends on DEBUG_OBJECTS
735	help
736	  This enables the selftest of the object debug code.
737
738config DEBUG_OBJECTS_FREE
739	bool "Debug objects in freed memory"
740	depends on DEBUG_OBJECTS
741	help
742	  This enables checks whether a k/v free operation frees an area
743	  which contains an object which has not been deactivated
744	  properly. This can make kmalloc/kfree-intensive workloads
745	  much slower.
746
747config DEBUG_OBJECTS_TIMERS
748	bool "Debug timer objects"
749	depends on DEBUG_OBJECTS
750	help
751	  If you say Y here, additional code will be inserted into the
752	  timer routines to track the life time of timer objects and
753	  validate the timer operations.
754
755config DEBUG_OBJECTS_WORK
756	bool "Debug work objects"
757	depends on DEBUG_OBJECTS
758	help
759	  If you say Y here, additional code will be inserted into the
760	  work queue routines to track the life time of work objects and
761	  validate the work operations.
762
763config DEBUG_OBJECTS_RCU_HEAD
764	bool "Debug RCU callbacks objects"
765	depends on DEBUG_OBJECTS
766	help
767	  Enable this to turn on debugging of RCU list heads (call_rcu() usage).
768
769config DEBUG_OBJECTS_PERCPU_COUNTER
770	bool "Debug percpu counter objects"
771	depends on DEBUG_OBJECTS
772	help
773	  If you say Y here, additional code will be inserted into the
774	  percpu counter routines to track the life time of percpu counter
775	  objects and validate the percpu counter operations.
776
777config DEBUG_OBJECTS_ENABLE_DEFAULT
778	int "debug_objects bootup default value (0-1)"
779	range 0 1
780	default "1"
781	depends on DEBUG_OBJECTS
782	help
783	  Debug objects boot parameter default value
784
785config SHRINKER_DEBUG
786	bool "Enable shrinker debugging support"
787	depends on DEBUG_FS
788	help
789	  Say Y to enable the shrinker debugfs interface which provides
790	  visibility into the kernel memory shrinkers subsystem.
791	  Disable it to avoid an extra memory footprint.
792
793config DEBUG_STACK_USAGE
794	bool "Stack utilization instrumentation"
795	depends on DEBUG_KERNEL
796	help
797	  Enables the display of the minimum amount of free stack which each
798	  task has ever had available in the sysrq-T and sysrq-P debug output.
799	  Also emits a message to dmesg when a process exits if that process
800	  used more stack space than previously exiting processes.
801
802	  This option will slow down process creation somewhat.
803
804config SCHED_STACK_END_CHECK
805	bool "Detect stack corruption on calls to schedule()"
806	depends on DEBUG_KERNEL
807	default n
808	help
809	  This option checks for a stack overrun on calls to schedule().
810	  If the stack end location is found to be over written always panic as
811	  the content of the corrupted region can no longer be trusted.
812	  This is to ensure no erroneous behaviour occurs which could result in
813	  data corruption or a sporadic crash at a later stage once the region
814	  is examined. The runtime overhead introduced is minimal.
815
816config ARCH_HAS_DEBUG_VM_PGTABLE
817	bool
818	help
819	  An architecture should select this when it can successfully
820	  build and run DEBUG_VM_PGTABLE.
821
822config DEBUG_VFS
823	bool "Debug VFS"
824	depends on DEBUG_KERNEL
825	help
826	  Enable this to turn on extended checks in the VFS layer that may impact
827	  performance.
828
829	  If unsure, say N.
830
831config DEBUG_VM_IRQSOFF
832	def_bool DEBUG_VM && !PREEMPT_RT
833
834config DEBUG_VM
835	bool "Debug VM"
836	depends on DEBUG_KERNEL
837	help
838	  Enable this to turn on extended checks in the virtual-memory system
839	  that may impact performance.
840
841	  If unsure, say N.
842
843config DEBUG_VM_SHOOT_LAZIES
844	bool "Debug MMU_LAZY_TLB_SHOOTDOWN implementation"
845	depends on DEBUG_VM
846	depends on MMU_LAZY_TLB_SHOOTDOWN
847	help
848	  Enable additional IPIs that ensure lazy tlb mm references are removed
849	  before the mm is freed.
850
851	  If unsure, say N.
852
853config DEBUG_VM_MAPLE_TREE
854	bool "Debug VM maple trees"
855	depends on DEBUG_VM
856	select DEBUG_MAPLE_TREE
857	help
858	  Enable VM maple tree debugging information and extra validations.
859
860	  If unsure, say N.
861
862config DEBUG_VM_RB
863	bool "Debug VM red-black trees"
864	depends on DEBUG_VM
865	help
866	  Enable VM red-black tree debugging information and extra validations.
867
868	  If unsure, say N.
869
870config DEBUG_VM_PGFLAGS
871	bool "Debug page-flags operations"
872	depends on DEBUG_VM
873	help
874	  Enables extra validation on page flags operations.
875
876	  If unsure, say N.
877
878config DEBUG_VM_PGTABLE
879	bool "Debug arch page table for semantics compliance"
880	depends on MMU
881	depends on ARCH_HAS_DEBUG_VM_PGTABLE
882	default y if DEBUG_VM
883	help
884	  This option provides a debug method which can be used to test
885	  architecture page table helper functions on various platforms in
886	  verifying if they comply with expected generic MM semantics. This
887	  will help architecture code in making sure that any changes or
888	  new additions of these helpers still conform to expected
889	  semantics of the generic MM. Platforms will have to opt in for
890	  this through ARCH_HAS_DEBUG_VM_PGTABLE.
891
892	  If unsure, say N.
893
894config ARCH_HAS_DEBUG_VIRTUAL
895	bool
896
897config DEBUG_VIRTUAL
898	bool "Debug VM translations"
899	depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
900	help
901	  Enable some costly sanity checks in virtual to page code. This can
902	  catch mistakes with virt_to_page() and friends.
903
904	  If unsure, say N.
905
906config DEBUG_NOMMU_REGIONS
907	bool "Debug the global anon/private NOMMU mapping region tree"
908	depends on DEBUG_KERNEL && !MMU
909	help
910	  This option causes the global tree of anonymous and private mapping
911	  regions to be regularly checked for invalid topology.
912
913config DEBUG_MEMORY_INIT
914	bool "Debug memory initialisation" if EXPERT
915	default !EXPERT
916	help
917	  Enable this for additional checks during memory initialisation.
918	  The sanity checks verify aspects of the VM such as the memory model
919	  and other information provided by the architecture. Verbose
920	  information will be printed at KERN_DEBUG loglevel depending
921	  on the mminit_loglevel= command-line option.
922
923	  If unsure, say Y
924
925config MEMORY_NOTIFIER_ERROR_INJECT
926	tristate "Memory hotplug notifier error injection module"
927	depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
928	help
929	  This option provides the ability to inject artificial errors to
930	  memory hotplug notifier chain callbacks.  It is controlled through
931	  debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
932
933	  If the notifier call chain should be failed with some events
934	  notified, write the error code to "actions/<notifier event>/error".
935
936	  Example: Inject memory hotplug offline error (-12 == -ENOMEM)
937
938	  # cd /sys/kernel/debug/notifier-error-inject/memory
939	  # echo -12 > actions/MEM_GOING_OFFLINE/error
940	  # echo offline > /sys/devices/system/memory/memoryXXX/state
941	  bash: echo: write error: Cannot allocate memory
942
943	  To compile this code as a module, choose M here: the module will
944	  be called memory-notifier-error-inject.
945
946	  If unsure, say N.
947
948config DEBUG_PER_CPU_MAPS
949	bool "Debug access to per_cpu maps"
950	depends on DEBUG_KERNEL
951	depends on SMP
952	help
953	  Say Y to verify that the per_cpu map being accessed has
954	  been set up. This adds a fair amount of code to kernel memory
955	  and decreases performance.
956
957	  Say N if unsure.
958
959config DEBUG_KMAP_LOCAL
960	bool "Debug kmap_local temporary mappings"
961	depends on DEBUG_KERNEL && KMAP_LOCAL
962	help
963	  This option enables additional error checking for the kmap_local
964	  infrastructure.  Disable for production use.
965
966config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
967	bool
968
969config DEBUG_KMAP_LOCAL_FORCE_MAP
970	bool "Enforce kmap_local temporary mappings"
971	depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
972	select KMAP_LOCAL
973	select DEBUG_KMAP_LOCAL
974	help
975	  This option enforces temporary mappings through the kmap_local
976	  mechanism for non-highmem pages and on non-highmem systems.
977	  Disable this for production systems!
978
979config DEBUG_HIGHMEM
980	bool "Highmem debugging"
981	depends on DEBUG_KERNEL && HIGHMEM
982	select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
983	select DEBUG_KMAP_LOCAL
984	help
985	  This option enables additional error checking for high memory
986	  systems.  Disable for production systems.
987
988config HAVE_DEBUG_STACKOVERFLOW
989	bool
990
991config DEBUG_STACKOVERFLOW
992	bool "Check for stack overflows"
993	depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
994	help
995	  Say Y here if you want to check for overflows of kernel, IRQ
996	  and exception stacks (if your architecture uses them). This
997	  option will show detailed messages if free stack space drops
998	  below a certain limit.
999
1000	  These kinds of bugs usually occur when call-chains in the
1001	  kernel get too deep, especially when interrupts are
1002	  involved.
1003
1004	  Use this in cases where you see apparently random memory
1005	  corruption, especially if it appears in 'struct thread_info'
1006
1007	  If in doubt, say "N".
1008
1009config CODE_TAGGING
1010	bool
1011	select KALLSYMS
1012
1013config MEM_ALLOC_PROFILING
1014	bool "Enable memory allocation profiling"
1015	default n
1016	depends on MMU
1017	depends on PROC_FS
1018	depends on !DEBUG_FORCE_WEAK_PER_CPU
1019	select CODE_TAGGING
1020	select PAGE_EXTENSION
1021	select SLAB_OBJ_EXT
1022	help
1023	  Track allocation source code and record total allocation size
1024	  initiated at that code location. The mechanism can be used to track
1025	  memory leaks with a low performance and memory impact.
1026
1027config MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
1028	bool "Enable memory allocation profiling by default"
1029	default y
1030	depends on MEM_ALLOC_PROFILING
1031
1032config MEM_ALLOC_PROFILING_DEBUG
1033	bool "Memory allocation profiler debugging"
1034	default n
1035	depends on MEM_ALLOC_PROFILING
1036	select MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
1037	help
1038	  Adds warnings with helpful error messages for memory allocation
1039	  profiling.
1040
1041source "lib/Kconfig.kasan"
1042source "lib/Kconfig.kfence"
1043source "lib/Kconfig.kmsan"
1044
1045endmenu # "Memory Debugging"
1046
1047config DEBUG_SHIRQ
1048	bool "Debug shared IRQ handlers"
1049	depends on DEBUG_KERNEL
1050	help
1051	  Enable this to generate a spurious interrupt just before a shared
1052	  interrupt handler is deregistered (generating one when registering
1053	  is currently disabled). Drivers need to handle this correctly. Some
1054	  don't and need to be caught.
1055
1056menu "Debug Oops, Lockups and Hangs"
1057
1058config PANIC_ON_OOPS
1059	bool "Panic on Oops"
1060	help
1061	  Say Y here to enable the kernel to panic when it oopses. This
1062	  has the same effect as setting oops=panic on the kernel command
1063	  line.
1064
1065	  This feature is useful to ensure that the kernel does not do
1066	  anything erroneous after an oops which could result in data
1067	  corruption or other issues.
1068
1069	  Say N if unsure.
1070
1071config PANIC_TIMEOUT
1072	int "panic timeout"
1073	default 0
1074	help
1075	  Set the timeout value (in seconds) until a reboot occurs when
1076	  the kernel panics. If n = 0, then we wait forever. A timeout
1077	  value n > 0 will wait n seconds before rebooting, while a timeout
1078	  value n < 0 will reboot immediately. This setting can be overridden
1079	  with the kernel command line option panic=, and from userspace via
1080	  /proc/sys/kernel/panic.
1081
1082config LOCKUP_DETECTOR
1083	bool
1084
1085config SOFTLOCKUP_DETECTOR
1086	bool "Detect Soft Lockups"
1087	depends on DEBUG_KERNEL && !S390
1088	select LOCKUP_DETECTOR
1089	help
1090	  Say Y here to enable the kernel to act as a watchdog to detect
1091	  soft lockups.
1092
1093	  Softlockups are bugs that cause the kernel to loop in kernel
1094	  mode for more than 20 seconds, without giving other tasks a
1095	  chance to run.  The current stack trace is displayed upon
1096	  detection and the system will stay locked up.
1097
1098config SOFTLOCKUP_DETECTOR_INTR_STORM
1099	bool "Detect Interrupt Storm in Soft Lockups"
1100	depends on SOFTLOCKUP_DETECTOR && IRQ_TIME_ACCOUNTING
1101	select GENERIC_IRQ_STAT_SNAPSHOT
1102	default y if NR_CPUS <= 128
1103	help
1104	  Say Y here to enable the kernel to detect interrupt storm
1105	  during "soft lockups".
1106
1107	  "soft lockups" can be caused by a variety of reasons. If one is
1108	  caused by an interrupt storm, then the storming interrupts will not
1109	  be on the callstack. To detect this case, it is necessary to report
1110	  the CPU stats and the interrupt counts during the "soft lockups".
1111
1112config BOOTPARAM_SOFTLOCKUP_PANIC
1113	int "Panic (Reboot) On Soft Lockups"
1114	depends on SOFTLOCKUP_DETECTOR
1115	default 0
1116	help
1117	  Set to a non-zero value N to enable the kernel to panic on "soft
1118	  lockups", which are bugs that cause the kernel to loop in kernel
1119	  mode for more than (N * 20 seconds) (configurable using the
1120	  watchdog_thresh sysctl), without giving other tasks a chance to run.
1121
1122	  The panic can be used in combination with panic_timeout,
1123	  to cause the system to reboot automatically after a
1124	  lockup has been detected. This feature is useful for
1125	  high-availability systems that have uptime guarantees and
1126	  where a lockup must be resolved ASAP.
1127
1128	  Say 0 if unsure.
1129
1130config HAVE_HARDLOCKUP_DETECTOR_BUDDY
1131	bool
1132	depends on SMP
1133	default y
1134
1135#
1136# Global switch whether to build a hardlockup detector at all. It is available
1137# only when the architecture supports at least one implementation. There are
1138# two exceptions. The hardlockup detector is never enabled on:
1139#
1140#	s390: it reported many false positives there
1141#
1142#	sparc64: has a custom implementation which is not using the common
1143#		hardlockup command line options and sysctl interface.
1144#
1145config HARDLOCKUP_DETECTOR
1146	bool "Detect Hard Lockups"
1147	depends on DEBUG_KERNEL && !S390 && !HARDLOCKUP_DETECTOR_SPARC64
1148	depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_BUDDY || HAVE_HARDLOCKUP_DETECTOR_ARCH
1149	imply HARDLOCKUP_DETECTOR_PERF
1150	imply HARDLOCKUP_DETECTOR_BUDDY
1151	imply HARDLOCKUP_DETECTOR_ARCH
1152	select LOCKUP_DETECTOR
1153
1154	help
1155	  Say Y here to enable the kernel to act as a watchdog to detect
1156	  hard lockups.
1157
1158	  Hardlockups are bugs that cause the CPU to loop in kernel mode
1159	  for more than 10 seconds, without letting other interrupts have a
1160	  chance to run.  The current stack trace is displayed upon detection
1161	  and the system will stay locked up.
1162
1163#
1164# Note that arch-specific variants are always preferred.
1165#
1166config HARDLOCKUP_DETECTOR_PREFER_BUDDY
1167	bool "Prefer the buddy CPU hardlockup detector"
1168	depends on HARDLOCKUP_DETECTOR
1169	depends on HAVE_HARDLOCKUP_DETECTOR_PERF && HAVE_HARDLOCKUP_DETECTOR_BUDDY
1170	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1171	help
1172	  Say Y here to prefer the buddy hardlockup detector over the perf one.
1173
1174	  With the buddy detector, each CPU uses its softlockup hrtimer
1175	  to check that the next CPU is processing hrtimer interrupts by
1176	  verifying that a counter is increasing.
1177
1178	  This hardlockup detector is useful on systems that don't have
1179	  an arch-specific hardlockup detector or if resources needed
1180	  for the hardlockup detector are better used for other things.
1181
1182config HARDLOCKUP_DETECTOR_PERF
1183	bool
1184	depends on HARDLOCKUP_DETECTOR
1185	depends on HAVE_HARDLOCKUP_DETECTOR_PERF && !HARDLOCKUP_DETECTOR_PREFER_BUDDY
1186	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1187	select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1188
1189config HARDLOCKUP_DETECTOR_BUDDY
1190	bool
1191	depends on HARDLOCKUP_DETECTOR
1192	depends on HAVE_HARDLOCKUP_DETECTOR_BUDDY
1193	depends on !HAVE_HARDLOCKUP_DETECTOR_PERF || HARDLOCKUP_DETECTOR_PREFER_BUDDY
1194	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1195	select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1196
1197config HARDLOCKUP_DETECTOR_ARCH
1198	bool
1199	depends on HARDLOCKUP_DETECTOR
1200	depends on HAVE_HARDLOCKUP_DETECTOR_ARCH
1201	help
1202	  The arch-specific implementation of the hardlockup detector will
1203	  be used.
1204
1205#
1206# Both the "perf" and "buddy" hardlockup detectors count hrtimer
1207# interrupts. This config enables functions managing this common code.
1208#
1209config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1210	bool
1211	select SOFTLOCKUP_DETECTOR
1212
1213#
1214# Enables a timestamp based low pass filter to compensate for perf based
1215# hard lockup detection which runs too fast due to turbo modes.
1216#
1217config HARDLOCKUP_CHECK_TIMESTAMP
1218	bool
1219
1220config BOOTPARAM_HARDLOCKUP_PANIC
1221	bool "Panic (Reboot) On Hard Lockups"
1222	depends on HARDLOCKUP_DETECTOR
1223	help
1224	  Say Y here to enable the kernel to panic on "hard lockups",
1225	  which are bugs that cause the kernel to loop in kernel
1226	  mode with interrupts disabled for more than 10 seconds (configurable
1227	  using the watchdog_thresh sysctl).
1228
1229	  Say N if unsure.
1230
1231config DETECT_HUNG_TASK
1232	bool "Detect Hung Tasks"
1233	depends on DEBUG_KERNEL
1234	default SOFTLOCKUP_DETECTOR
1235	help
1236	  Say Y here to enable the kernel to detect "hung tasks",
1237	  which are bugs that cause the task to be stuck in
1238	  uninterruptible "D" state indefinitely.
1239
1240	  When a hung task is detected, the kernel will print the
1241	  current stack trace (which you should report), but the
1242	  task will stay in uninterruptible state. If lockdep is
1243	  enabled then all held locks will also be reported. This
1244	  feature has negligible overhead.
1245
1246config DEFAULT_HUNG_TASK_TIMEOUT
1247	int "Default timeout for hung task detection (in seconds)"
1248	depends on DETECT_HUNG_TASK
1249	default 120
1250	help
1251	  This option controls the default timeout (in seconds) used
1252	  to determine when a task has become non-responsive and should
1253	  be considered hung.
1254
1255	  It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1256	  sysctl or by writing a value to
1257	  /proc/sys/kernel/hung_task_timeout_secs.
1258
1259	  A timeout of 0 disables the check.  The default is two minutes.
1260	  Keeping the default should be fine in most cases.
1261
1262config BOOTPARAM_HUNG_TASK_PANIC
1263	int "Number of hung tasks to trigger kernel panic"
1264	depends on DETECT_HUNG_TASK
1265	default 0
1266	help
1267	  When set to a non-zero value, a kernel panic will be triggered
1268	  if the number of hung tasks found during a single scan reaches
1269	  this value.
1270
1271	  The panic can be used in combination with panic_timeout,
1272	  to cause the system to reboot automatically after a
1273	  hung task has been detected. This feature is useful for
1274	  high-availability systems that have uptime guarantees and
1275	  where a hung tasks must be resolved ASAP.
1276
1277	  Say 0 if unsure.
1278
1279config DETECT_HUNG_TASK_BLOCKER
1280	bool "Dump Hung Tasks Blocker"
1281	depends on DETECT_HUNG_TASK
1282	depends on !PREEMPT_RT
1283	default y
1284	help
1285	  Say Y here to show the blocker task's stacktrace who acquires
1286	  the mutex lock which "hung tasks" are waiting.
1287	  This will add overhead a bit but shows suspicious tasks and
1288	  call trace if it comes from waiting a mutex.
1289
1290config WQ_WATCHDOG
1291	bool "Detect Workqueue Stalls"
1292	depends on DEBUG_KERNEL
1293	help
1294	  Say Y here to enable stall detection on workqueues.  If a
1295	  worker pool doesn't make forward progress on a pending work
1296	  item for over a given amount of time, 30s by default, a
1297	  warning message is printed along with dump of workqueue
1298	  state.  This can be configured through kernel parameter
1299	  "workqueue.watchdog_thresh" and its sysfs counterpart.
1300
1301config WQ_CPU_INTENSIVE_REPORT
1302	bool "Report per-cpu work items which hog CPU for too long"
1303	depends on DEBUG_KERNEL
1304	help
1305	  Say Y here to enable reporting of concurrency-managed per-cpu work
1306	  items that hog CPUs for longer than
1307	  workqueue.cpu_intensive_thresh_us. Workqueue automatically
1308	  detects and excludes them from concurrency management to prevent
1309	  them from stalling other per-cpu work items. Occassional
1310	  triggering may not necessarily indicate a problem. Repeated
1311	  triggering likely indicates that the work item should be switched
1312	  to use an unbound workqueue.
1313
1314config TEST_LOCKUP
1315	tristate "Test module to generate lockups"
1316	depends on m
1317	help
1318	  This builds the "test_lockup" module that helps to make sure
1319	  that watchdogs and lockup detectors are working properly.
1320
1321	  Depending on module parameters it could emulate soft or hard
1322	  lockup, "hung task", or locking arbitrary lock for a long time.
1323	  Also it could generate series of lockups with cooling-down periods.
1324
1325	  If unsure, say N.
1326
1327endmenu # "Debug lockups and hangs"
1328
1329menu "Scheduler Debugging"
1330
1331config SCHED_INFO
1332	bool
1333	default n
1334
1335config SCHEDSTATS
1336	bool "Collect scheduler statistics"
1337	depends on PROC_FS
1338	select SCHED_INFO
1339	help
1340	  If you say Y here, additional code will be inserted into the
1341	  scheduler and related routines to collect statistics about
1342	  scheduler behavior and provide them in /proc/schedstat.  These
1343	  stats may be useful for both tuning and debugging the scheduler
1344	  If you aren't debugging the scheduler or trying to tune a specific
1345	  application, you can say N to avoid the very slight overhead
1346	  this adds.
1347
1348endmenu
1349
1350config DEBUG_PREEMPT
1351	bool "Debug preemptible kernel"
1352	depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1353	help
1354	  If you say Y here then the kernel will use a debug variant of the
1355	  commonly used smp_processor_id() function and will print warnings
1356	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
1357	  will detect preemption count underflows.
1358
1359	  This option has potential to introduce high runtime overhead,
1360	  depending on workload as it triggers debugging routines for each
1361	  this_cpu operation. It should only be used for debugging purposes.
1362
1363menu "Lock Debugging (spinlocks, mutexes, etc...)"
1364
1365config LOCK_DEBUGGING_SUPPORT
1366	bool
1367	depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1368	default y
1369
1370config PROVE_LOCKING
1371	bool "Lock debugging: prove locking correctness"
1372	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1373	select LOCKDEP
1374	select DEBUG_SPINLOCK
1375	select DEBUG_MUTEXES if !PREEMPT_RT
1376	select DEBUG_RT_MUTEXES if RT_MUTEXES
1377	select DEBUG_RWSEMS if !PREEMPT_RT
1378	select DEBUG_WW_MUTEX_SLOWPATH
1379	select DEBUG_LOCK_ALLOC
1380	select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1381	select TRACE_IRQFLAGS
1382	default n
1383	help
1384	 This feature enables the kernel to prove that all locking
1385	 that occurs in the kernel runtime is mathematically
1386	 correct: that under no circumstance could an arbitrary (and
1387	 not yet triggered) combination of observed locking
1388	 sequences (on an arbitrary number of CPUs, running an
1389	 arbitrary number of tasks and interrupt contexts) cause a
1390	 deadlock.
1391
1392	 In short, this feature enables the kernel to report locking
1393	 related deadlocks before they actually occur.
1394
1395	 The proof does not depend on how hard and complex a
1396	 deadlock scenario would be to trigger: how many
1397	 participant CPUs, tasks and irq-contexts would be needed
1398	 for it to trigger. The proof also does not depend on
1399	 timing: if a race and a resulting deadlock is possible
1400	 theoretically (no matter how unlikely the race scenario
1401	 is), it will be proven so and will immediately be
1402	 reported by the kernel (once the event is observed that
1403	 makes the deadlock theoretically possible).
1404
1405	 If a deadlock is impossible (i.e. the locking rules, as
1406	 observed by the kernel, are mathematically correct), the
1407	 kernel reports nothing.
1408
1409	 NOTE: this feature can also be enabled for rwlocks, mutexes
1410	 and rwsems - in which case all dependencies between these
1411	 different locking variants are observed and mapped too, and
1412	 the proof of observed correctness is also maintained for an
1413	 arbitrary combination of these separate locking variants.
1414
1415	 For more details, see Documentation/locking/lockdep-design.rst.
1416
1417config PROVE_RAW_LOCK_NESTING
1418	bool "Enable raw_spinlock - spinlock nesting checks" if !ARCH_SUPPORTS_RT
1419	depends on PROVE_LOCKING
1420	default y if ARCH_SUPPORTS_RT
1421	help
1422	 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1423	 that the lock nesting rules for PREEMPT_RT enabled kernels are
1424	 not violated.
1425
1426config LOCK_STAT
1427	bool "Lock usage statistics"
1428	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1429	select LOCKDEP
1430	select DEBUG_SPINLOCK
1431	select DEBUG_MUTEXES if !PREEMPT_RT
1432	select DEBUG_RT_MUTEXES if RT_MUTEXES
1433	select DEBUG_LOCK_ALLOC
1434	default n
1435	help
1436	 This feature enables tracking lock contention points
1437
1438	 For more details, see Documentation/locking/lockstat.rst
1439
1440	 This also enables lock events required by "perf lock",
1441	 subcommand of perf.
1442	 If you want to use "perf lock", you also need to turn on
1443	 CONFIG_EVENT_TRACING.
1444
1445	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1446	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1447
1448config DEBUG_RT_MUTEXES
1449	bool "RT Mutex debugging, deadlock detection"
1450	depends on DEBUG_KERNEL && RT_MUTEXES
1451	help
1452	 This allows rt mutex semantics violations and rt mutex related
1453	 deadlocks (lockups) to be detected and reported automatically.
1454
1455config DEBUG_SPINLOCK
1456	bool "Spinlock and rw-lock debugging: basic checks"
1457	depends on DEBUG_KERNEL
1458	select UNINLINE_SPIN_UNLOCK
1459	help
1460	  Say Y here and build SMP to catch missing spinlock initialization
1461	  and certain other kinds of spinlock errors commonly made.  This is
1462	  best used in conjunction with the NMI watchdog so that spinlock
1463	  deadlocks are also debuggable.
1464
1465config DEBUG_MUTEXES
1466	bool "Mutex debugging: basic checks"
1467	depends on DEBUG_KERNEL && !PREEMPT_RT
1468	help
1469	 This feature allows mutex semantics violations to be detected and
1470	 reported.
1471
1472config DEBUG_WW_MUTEX_SLOWPATH
1473	bool "Wait/wound mutex debugging: Slowpath testing"
1474	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1475	select DEBUG_LOCK_ALLOC
1476	select DEBUG_SPINLOCK
1477	select DEBUG_MUTEXES if !PREEMPT_RT
1478	select DEBUG_RT_MUTEXES if PREEMPT_RT
1479	help
1480	 This feature enables slowpath testing for w/w mutex users by
1481	 injecting additional -EDEADLK wound/backoff cases. Together with
1482	 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1483	 will test all possible w/w mutex interface abuse with the
1484	 exception of simply not acquiring all the required locks.
1485	 Note that this feature can introduce significant overhead, so
1486	 it really should not be enabled in a production or distro kernel,
1487	 even a debug kernel.  If you are a driver writer, enable it.  If
1488	 you are a distro, do not.
1489
1490config DEBUG_RWSEMS
1491	bool "RW Semaphore debugging: basic checks"
1492	depends on DEBUG_KERNEL && !PREEMPT_RT
1493	help
1494	  This debugging feature allows mismatched rw semaphore locks
1495	  and unlocks to be detected and reported.
1496
1497config DEBUG_LOCK_ALLOC
1498	bool "Lock debugging: detect incorrect freeing of live locks"
1499	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1500	select DEBUG_SPINLOCK
1501	select DEBUG_MUTEXES if !PREEMPT_RT
1502	select DEBUG_RT_MUTEXES if RT_MUTEXES
1503	select LOCKDEP
1504	help
1505	 This feature will check whether any held lock (spinlock, rwlock,
1506	 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1507	 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1508	 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1509	 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1510	 held during task exit.
1511
1512config LOCKDEP
1513	bool
1514	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1515	select STACKTRACE
1516	select KALLSYMS
1517	select KALLSYMS_ALL
1518
1519config LOCKDEP_SMALL
1520	bool
1521
1522config LOCKDEP_BITS
1523	int "Size for MAX_LOCKDEP_ENTRIES (as Nth power of 2)"
1524	depends on LOCKDEP && !LOCKDEP_SMALL
1525	range 10 24
1526	default 15
1527	help
1528	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1529
1530config LOCKDEP_CHAINS_BITS
1531	int "Size for MAX_LOCKDEP_CHAINS (as Nth power of 2)"
1532	depends on LOCKDEP && !LOCKDEP_SMALL
1533	range 10 21
1534	default 16
1535	help
1536	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1537
1538config LOCKDEP_STACK_TRACE_BITS
1539	int "Size for MAX_STACK_TRACE_ENTRIES (as Nth power of 2)"
1540	depends on LOCKDEP && !LOCKDEP_SMALL
1541	range 10 26
1542	default 19
1543	help
1544	  Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1545
1546config LOCKDEP_STACK_TRACE_HASH_BITS
1547	int "Size for STACK_TRACE_HASH_SIZE (as Nth power of 2)"
1548	depends on LOCKDEP && !LOCKDEP_SMALL
1549	range 10 26
1550	default 14
1551	help
1552	  Try increasing this value if you need large STACK_TRACE_HASH_SIZE.
1553
1554config LOCKDEP_CIRCULAR_QUEUE_BITS
1555	int "Size for elements in circular_queue struct (as Nth power of 2)"
1556	depends on LOCKDEP
1557	range 10 26
1558	default 12
1559	help
1560	  Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1561
1562config DEBUG_LOCKDEP
1563	bool "Lock dependency engine debugging"
1564	depends on DEBUG_KERNEL && LOCKDEP
1565	select DEBUG_IRQFLAGS
1566	help
1567	  If you say Y here, the lock dependency engine will do
1568	  additional runtime checks to debug itself, at the price
1569	  of more runtime overhead.
1570
1571config DEBUG_ATOMIC_SLEEP
1572	bool "Sleep inside atomic section checking"
1573	select PREEMPT_COUNT
1574	depends on DEBUG_KERNEL
1575	depends on !ARCH_NO_PREEMPT
1576	help
1577	  If you say Y here, various routines which may sleep will become very
1578	  noisy if they are called inside atomic sections: when a spinlock is
1579	  held, inside an rcu read side critical section, inside preempt disabled
1580	  sections, inside an interrupt, etc...
1581
1582config DEBUG_LOCKING_API_SELFTESTS
1583	bool "Locking API boot-time self-tests"
1584	depends on DEBUG_KERNEL
1585	help
1586	  Say Y here if you want the kernel to run a short self-test during
1587	  bootup. The self-test checks whether common types of locking bugs
1588	  are detected by debugging mechanisms or not. (if you disable
1589	  lock debugging then those bugs won't be detected of course.)
1590	  The following locking APIs are covered: spinlocks, rwlocks,
1591	  mutexes and rwsems.
1592
1593config LOCK_TORTURE_TEST
1594	tristate "torture tests for locking"
1595	depends on DEBUG_KERNEL
1596	select TORTURE_TEST
1597	help
1598	  This option provides a kernel module that runs torture tests
1599	  on kernel locking primitives.  The kernel module may be built
1600	  after the fact on the running kernel to be tested, if desired.
1601
1602	  Say Y here if you want kernel locking-primitive torture tests
1603	  to be built into the kernel.
1604	  Say M if you want these torture tests to build as a module.
1605	  Say N if you are unsure.
1606
1607config WW_MUTEX_SELFTEST
1608	tristate "Wait/wound mutex selftests"
1609	help
1610	  This option provides a kernel module that runs tests on the
1611	  on the struct ww_mutex locking API.
1612
1613	  It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1614	  with this test harness.
1615
1616	  Say M if you want these self tests to build as a module.
1617	  Say N if you are unsure.
1618
1619config SCF_TORTURE_TEST
1620	tristate "torture tests for smp_call_function*()"
1621	depends on DEBUG_KERNEL
1622	select TORTURE_TEST
1623	help
1624	  This option provides a kernel module that runs torture tests
1625	  on the smp_call_function() family of primitives.  The kernel
1626	  module may be built after the fact on the running kernel to
1627	  be tested, if desired.
1628
1629config CSD_LOCK_WAIT_DEBUG
1630	bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1631	depends on DEBUG_KERNEL
1632	depends on SMP
1633	depends on 64BIT
1634	default n
1635	help
1636	  This option enables debug prints when CPUs are slow to respond
1637	  to the smp_call_function*() IPI wrappers.  These debug prints
1638	  include the IPI handler function currently executing (if any)
1639	  and relevant stack traces.
1640
1641config CSD_LOCK_WAIT_DEBUG_DEFAULT
1642	bool "Default csd_lock_wait() debugging on at boot time"
1643	depends on CSD_LOCK_WAIT_DEBUG
1644	depends on 64BIT
1645	default n
1646	help
1647	  This option causes the csdlock_debug= kernel boot parameter to
1648	  default to 1 (basic debugging) instead of 0 (no debugging).
1649
1650endmenu # lock debugging
1651
1652config TRACE_IRQFLAGS
1653	depends on TRACE_IRQFLAGS_SUPPORT
1654	bool
1655	help
1656	  Enables hooks to interrupt enabling and disabling for
1657	  either tracing or lock debugging.
1658
1659config TRACE_IRQFLAGS_NMI
1660	def_bool y
1661	depends on TRACE_IRQFLAGS
1662	depends on TRACE_IRQFLAGS_NMI_SUPPORT
1663
1664config NMI_CHECK_CPU
1665	bool "Debugging for CPUs failing to respond to backtrace requests"
1666	depends on DEBUG_KERNEL
1667	depends on X86
1668	default n
1669	help
1670	  Enables debug prints when a CPU fails to respond to a given
1671	  backtrace NMI.  These prints provide some reasons why a CPU
1672	  might legitimately be failing to respond, for example, if it
1673	  is offline of if ignore_nmis is set.
1674
1675config DEBUG_IRQFLAGS
1676	bool "Debug IRQ flag manipulation"
1677	help
1678	  Enables checks for potentially unsafe enabling or disabling of
1679	  interrupts, such as calling raw_local_irq_restore() when interrupts
1680	  are enabled.
1681
1682config STACKTRACE
1683	bool "Stack backtrace support"
1684	depends on STACKTRACE_SUPPORT
1685	help
1686	  This option causes the kernel to create a /proc/pid/stack for
1687	  every process, showing its current stack trace.
1688	  It is also used by various kernel debugging features that require
1689	  stack trace generation.
1690
1691config WARN_ALL_UNSEEDED_RANDOM
1692	bool "Warn for all uses of unseeded randomness"
1693	default n
1694	help
1695	  Some parts of the kernel contain bugs relating to their use of
1696	  cryptographically secure random numbers before it's actually possible
1697	  to generate those numbers securely. This setting ensures that these
1698	  flaws don't go unnoticed, by enabling a message, should this ever
1699	  occur. This will allow people with obscure setups to know when things
1700	  are going wrong, so that they might contact developers about fixing
1701	  it.
1702
1703	  Unfortunately, on some models of some architectures getting
1704	  a fully seeded CRNG is extremely difficult, and so this can
1705	  result in dmesg getting spammed for a surprisingly long
1706	  time.  This is really bad from a security perspective, and
1707	  so architecture maintainers really need to do what they can
1708	  to get the CRNG seeded sooner after the system is booted.
1709	  However, since users cannot do anything actionable to
1710	  address this, by default this option is disabled.
1711
1712	  Say Y here if you want to receive warnings for all uses of
1713	  unseeded randomness.  This will be of use primarily for
1714	  those developers interested in improving the security of
1715	  Linux kernels running on their architecture (or
1716	  subarchitecture).
1717
1718config DEBUG_KOBJECT
1719	bool "kobject debugging"
1720	depends on DEBUG_KERNEL
1721	help
1722	  If you say Y here, some extra kobject debugging messages will be sent
1723	  to the syslog.
1724
1725config DEBUG_KOBJECT_RELEASE
1726	bool "kobject release debugging"
1727	depends on DEBUG_OBJECTS_TIMERS
1728	help
1729	  kobjects are reference counted objects.  This means that their
1730	  last reference count put is not predictable, and the kobject can
1731	  live on past the point at which a driver decides to drop its
1732	  initial reference to the kobject gained on allocation.  An
1733	  example of this would be a struct device which has just been
1734	  unregistered.
1735
1736	  However, some buggy drivers assume that after such an operation,
1737	  the memory backing the kobject can be immediately freed.  This
1738	  goes completely against the principles of a refcounted object.
1739
1740	  If you say Y here, the kernel will delay the release of kobjects
1741	  on the last reference count to improve the visibility of this
1742	  kind of kobject release bug.
1743
1744config HAVE_DEBUG_BUGVERBOSE
1745	bool
1746
1747menu "Debug kernel data structures"
1748
1749config DEBUG_LIST
1750	bool "Debug linked list manipulation"
1751	depends on DEBUG_KERNEL
1752	select LIST_HARDENED
1753	help
1754	  Enable this to turn on extended checks in the linked-list walking
1755	  routines.
1756
1757	  This option trades better quality error reports for performance, and
1758	  is more suitable for kernel debugging. If you care about performance,
1759	  you should only enable CONFIG_LIST_HARDENED instead.
1760
1761	  If unsure, say N.
1762
1763config DEBUG_PLIST
1764	bool "Debug priority linked list manipulation"
1765	depends on DEBUG_KERNEL
1766	help
1767	  Enable this to turn on extended checks in the priority-ordered
1768	  linked-list (plist) walking routines.  This checks the entire
1769	  list multiple times during each manipulation.
1770
1771	  If unsure, say N.
1772
1773config DEBUG_SG
1774	bool "Debug SG table operations"
1775	depends on DEBUG_KERNEL
1776	help
1777	  Enable this to turn on checks on scatter-gather tables. This can
1778	  help find problems with drivers that do not properly initialize
1779	  their sg tables.
1780
1781	  If unsure, say N.
1782
1783config DEBUG_NOTIFIERS
1784	bool "Debug notifier call chains"
1785	depends on DEBUG_KERNEL
1786	help
1787	  Enable this to turn on sanity checking for notifier call chains.
1788	  This is most useful for kernel developers to make sure that
1789	  modules properly unregister themselves from notifier chains.
1790	  This is a relatively cheap check but if you care about maximum
1791	  performance, say N.
1792
1793config DEBUG_CLOSURES
1794	bool "Debug closures (bcache async widgits)"
1795	depends on CLOSURES
1796	select DEBUG_FS
1797	help
1798	  Keeps all active closures in a linked list and provides a debugfs
1799	  interface to list them, which makes it possible to see asynchronous
1800	  operations that get stuck.
1801
1802config DEBUG_MAPLE_TREE
1803	bool "Debug maple trees"
1804	depends on DEBUG_KERNEL
1805	help
1806	  Enable maple tree debugging information and extra validations.
1807
1808	  If unsure, say N.
1809
1810endmenu
1811
1812source "kernel/rcu/Kconfig.debug"
1813
1814config DEBUG_WQ_FORCE_RR_CPU
1815	bool "Force round-robin CPU selection for unbound work items"
1816	depends on DEBUG_KERNEL
1817	default n
1818	help
1819	  Workqueue used to implicitly guarantee that work items queued
1820	  without explicit CPU specified are put on the local CPU.  This
1821	  guarantee is no longer true and while local CPU is still
1822	  preferred work items may be put on foreign CPUs.  Kernel
1823	  parameter "workqueue.debug_force_rr_cpu" is added to force
1824	  round-robin CPU selection to flush out usages which depend on the
1825	  now broken guarantee.  This config option enables the debug
1826	  feature by default.  When enabled, memory and cache locality will
1827	  be impacted.
1828
1829config CPU_HOTPLUG_STATE_CONTROL
1830	bool "Enable CPU hotplug state control"
1831	depends on DEBUG_KERNEL
1832	depends on HOTPLUG_CPU
1833	default n
1834	help
1835	  Allows to write steps between "offline" and "online" to the CPUs
1836	  sysfs target file so states can be stepped granular. This is a debug
1837	  option for now as the hotplug machinery cannot be stopped and
1838	  restarted at arbitrary points yet.
1839
1840	  Say N if your are unsure.
1841
1842config LATENCYTOP
1843	bool "Latency measuring infrastructure"
1844	depends on DEBUG_KERNEL
1845	depends on STACKTRACE_SUPPORT
1846	depends on PROC_FS
1847	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1848	select KALLSYMS
1849	select KALLSYMS_ALL
1850	select STACKTRACE
1851	select SCHEDSTATS
1852	help
1853	  Enable this option if you want to use the LatencyTOP tool
1854	  to find out which userspace is blocking on what kernel operations.
1855
1856config DEBUG_CGROUP_REF
1857	bool "Disable inlining of cgroup css reference count functions"
1858	depends on DEBUG_KERNEL
1859	depends on CGROUPS
1860	depends on KPROBES
1861	default n
1862	help
1863	  Force cgroup css reference count functions to not be inlined so
1864	  that they can be kprobed for debugging.
1865
1866source "kernel/trace/Kconfig"
1867
1868config PROVIDE_OHCI1394_DMA_INIT
1869	bool "Remote debugging over FireWire early on boot"
1870	depends on PCI && X86
1871	help
1872	  If you want to debug problems which hang or crash the kernel early
1873	  on boot and the crashing machine has a FireWire port, you can use
1874	  this feature to remotely access the memory of the crashed machine
1875	  over FireWire. This employs remote DMA as part of the OHCI1394
1876	  specification which is now the standard for FireWire controllers.
1877
1878	  With remote DMA, you can monitor the printk buffer remotely using
1879	  firescope and access all memory below 4GB using fireproxy from gdb.
1880	  Even controlling a kernel debugger is possible using remote DMA.
1881
1882	  Usage:
1883
1884	  If ohci1394_dma=early is used as boot parameter, it will initialize
1885	  all OHCI1394 controllers which are found in the PCI config space.
1886
1887	  As all changes to the FireWire bus such as enabling and disabling
1888	  devices cause a bus reset and thereby disable remote DMA for all
1889	  devices, be sure to have the cable plugged and FireWire enabled on
1890	  the debugging host before booting the debug target for debugging.
1891
1892	  This code (~1k) is freed after boot. By then, the firewire stack
1893	  in charge of the OHCI-1394 controllers should be used instead.
1894
1895	  See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1896
1897source "samples/Kconfig"
1898
1899config ARCH_HAS_DEVMEM_IS_ALLOWED
1900	bool
1901
1902config STRICT_DEVMEM
1903	bool "Filter access to /dev/mem"
1904	depends on MMU && DEVMEM
1905	depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1906	default y if PPC || X86 || ARM64 || S390
1907	help
1908	  If this option is disabled, you allow userspace (root) access to all
1909	  of memory, including kernel and userspace memory. Accidental
1910	  access to this is obviously disastrous, but specific access can
1911	  be used by people debugging the kernel. Note that with PAT support
1912	  enabled, even in this case there are restrictions on /dev/mem
1913	  use due to the cache aliasing requirements.
1914
1915	  If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1916	  file only allows userspace access to PCI space and the BIOS code and
1917	  data regions.  This is sufficient for dosemu and X and all common
1918	  users of /dev/mem.
1919
1920	  If in doubt, say Y.
1921
1922config IO_STRICT_DEVMEM
1923	bool "Filter I/O access to /dev/mem"
1924	depends on STRICT_DEVMEM
1925	help
1926	  If this option is disabled, you allow userspace (root) access to all
1927	  io-memory regardless of whether a driver is actively using that
1928	  range.  Accidental access to this is obviously disastrous, but
1929	  specific access can be used by people debugging kernel drivers.
1930
1931	  If this option is switched on, the /dev/mem file only allows
1932	  userspace access to *idle* io-memory ranges (see /proc/iomem) This
1933	  may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1934	  if the driver using a given range cannot be disabled.
1935
1936	  If in doubt, say Y.
1937
1938menu "$(SRCARCH) Debugging"
1939
1940source "arch/$(SRCARCH)/Kconfig.debug"
1941
1942endmenu
1943
1944menu "Kernel Testing and Coverage"
1945
1946source "lib/kunit/Kconfig"
1947
1948config NOTIFIER_ERROR_INJECTION
1949	tristate "Notifier error injection"
1950	depends on DEBUG_KERNEL
1951	select DEBUG_FS
1952	help
1953	  This option provides the ability to inject artificial errors to
1954	  specified notifier chain callbacks. It is useful to test the error
1955	  handling of notifier call chain failures.
1956
1957	  Say N if unsure.
1958
1959config PM_NOTIFIER_ERROR_INJECT
1960	tristate "PM notifier error injection module"
1961	depends on PM && NOTIFIER_ERROR_INJECTION
1962	default m if PM_DEBUG
1963	help
1964	  This option provides the ability to inject artificial errors to
1965	  PM notifier chain callbacks.  It is controlled through debugfs
1966	  interface /sys/kernel/debug/notifier-error-inject/pm
1967
1968	  If the notifier call chain should be failed with some events
1969	  notified, write the error code to "actions/<notifier event>/error".
1970
1971	  Example: Inject PM suspend error (-12 = -ENOMEM)
1972
1973	  # cd /sys/kernel/debug/notifier-error-inject/pm/
1974	  # echo -12 > actions/PM_SUSPEND_PREPARE/error
1975	  # echo mem > /sys/power/state
1976	  bash: echo: write error: Cannot allocate memory
1977
1978	  To compile this code as a module, choose M here: the module will
1979	  be called pm-notifier-error-inject.
1980
1981	  If unsure, say N.
1982
1983config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1984	tristate "OF reconfig notifier error injection module"
1985	depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1986	help
1987	  This option provides the ability to inject artificial errors to
1988	  OF reconfig notifier chain callbacks.  It is controlled
1989	  through debugfs interface under
1990	  /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1991
1992	  If the notifier call chain should be failed with some events
1993	  notified, write the error code to "actions/<notifier event>/error".
1994
1995	  To compile this code as a module, choose M here: the module will
1996	  be called of-reconfig-notifier-error-inject.
1997
1998	  If unsure, say N.
1999
2000config NETDEV_NOTIFIER_ERROR_INJECT
2001	tristate "Netdev notifier error injection module"
2002	depends on NET && NOTIFIER_ERROR_INJECTION
2003	help
2004	  This option provides the ability to inject artificial errors to
2005	  netdevice notifier chain callbacks.  It is controlled through debugfs
2006	  interface /sys/kernel/debug/notifier-error-inject/netdev
2007
2008	  If the notifier call chain should be failed with some events
2009	  notified, write the error code to "actions/<notifier event>/error".
2010
2011	  Example: Inject netdevice mtu change error (-22 = -EINVAL)
2012
2013	  # cd /sys/kernel/debug/notifier-error-inject/netdev
2014	  # echo -22 > actions/NETDEV_CHANGEMTU/error
2015	  # ip link set eth0 mtu 1024
2016	  RTNETLINK answers: Invalid argument
2017
2018	  To compile this code as a module, choose M here: the module will
2019	  be called netdev-notifier-error-inject.
2020
2021	  If unsure, say N.
2022
2023config FUNCTION_ERROR_INJECTION
2024	bool "Fault-injections of functions"
2025	depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
2026	help
2027	  Add fault injections into various functions that are annotated with
2028	  ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
2029	  value of these functions. This is useful to test error paths of code.
2030
2031	  If unsure, say N
2032
2033config FAULT_INJECTION
2034	bool "Fault-injection framework"
2035	depends on DEBUG_KERNEL
2036	help
2037	  Provide fault-injection framework.
2038	  For more details, see Documentation/fault-injection/.
2039
2040config FAILSLAB
2041	bool "Fault-injection capability for kmalloc"
2042	depends on FAULT_INJECTION
2043	help
2044	  Provide fault-injection capability for kmalloc.
2045
2046config FAIL_PAGE_ALLOC
2047	bool "Fault-injection capability for alloc_pages()"
2048	depends on FAULT_INJECTION
2049	help
2050	  Provide fault-injection capability for alloc_pages().
2051
2052config FAULT_INJECTION_USERCOPY
2053	bool "Fault injection capability for usercopy functions"
2054	depends on FAULT_INJECTION
2055	help
2056	  Provides fault-injection capability to inject failures
2057	  in usercopy functions (copy_from_user(), get_user(), ...).
2058
2059config FAIL_MAKE_REQUEST
2060	bool "Fault-injection capability for disk IO"
2061	depends on FAULT_INJECTION && BLOCK
2062	help
2063	  Provide fault-injection capability for disk IO.
2064
2065config FAIL_IO_TIMEOUT
2066	bool "Fault-injection capability for faking disk interrupts"
2067	depends on FAULT_INJECTION && BLOCK
2068	help
2069	  Provide fault-injection capability on end IO handling. This
2070	  will make the block layer "forget" an interrupt as configured,
2071	  thus exercising the error handling.
2072
2073	  Only works with drivers that use the generic timeout handling,
2074	  for others it won't do anything.
2075
2076config FAIL_FUTEX
2077	bool "Fault-injection capability for futexes"
2078	select DEBUG_FS
2079	depends on FAULT_INJECTION && FUTEX
2080	help
2081	  Provide fault-injection capability for futexes.
2082
2083config FAULT_INJECTION_DEBUG_FS
2084	bool "Debugfs entries for fault-injection capabilities"
2085	depends on FAULT_INJECTION && SYSFS && DEBUG_FS
2086	help
2087	  Enable configuration of fault-injection capabilities via debugfs.
2088
2089config FAIL_FUNCTION
2090	bool "Fault-injection capability for functions"
2091	depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
2092	help
2093	  Provide function-based fault-injection capability.
2094	  This will allow you to override a specific function with a return
2095	  with given return value. As a result, function caller will see
2096	  an error value and have to handle it. This is useful to test the
2097	  error handling in various subsystems.
2098
2099config FAIL_MMC_REQUEST
2100	bool "Fault-injection capability for MMC IO"
2101	depends on FAULT_INJECTION_DEBUG_FS && MMC
2102	help
2103	  Provide fault-injection capability for MMC IO.
2104	  This will make the mmc core return data errors. This is
2105	  useful to test the error handling in the mmc block device
2106	  and to test how the mmc host driver handles retries from
2107	  the block device.
2108
2109config FAIL_SUNRPC
2110	bool "Fault-injection capability for SunRPC"
2111	depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2112	help
2113	  Provide fault-injection capability for SunRPC and
2114	  its consumers.
2115
2116config FAIL_SKB_REALLOC
2117	bool "Fault-injection capability forcing skb to reallocate"
2118	depends on FAULT_INJECTION_DEBUG_FS
2119	help
2120	  Provide fault-injection capability that forces the skb to be
2121	  reallocated, catching possible invalid pointers to the skb.
2122
2123	  For more information, check
2124	  Documentation/fault-injection/fault-injection.rst
2125
2126config FAULT_INJECTION_CONFIGFS
2127	bool "Configfs interface for fault-injection capabilities"
2128	depends on FAULT_INJECTION
2129	select CONFIGFS_FS
2130	help
2131	  This option allows configfs-based drivers to dynamically configure
2132	  fault-injection via configfs.  Each parameter for driver-specific
2133	  fault-injection can be made visible as a configfs attribute in a
2134	  configfs group.
2135
2136
2137config FAULT_INJECTION_STACKTRACE_FILTER
2138	bool "stacktrace filter for fault-injection capabilities"
2139	depends on FAULT_INJECTION
2140	depends on (FAULT_INJECTION_DEBUG_FS || FAULT_INJECTION_CONFIGFS) && STACKTRACE_SUPPORT
2141	select STACKTRACE
2142	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2143	help
2144	  Provide stacktrace filter for fault-injection capabilities
2145
2146config ARCH_HAS_KCOV
2147	bool
2148	help
2149	  An architecture should select this when it can successfully
2150	  build and run with CONFIG_KCOV. This typically requires
2151	  disabling instrumentation for some early boot code.
2152
2153config KCOV
2154	bool "Code coverage for fuzzing"
2155	depends on ARCH_HAS_KCOV
2156	depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2157		   GCC_VERSION >= 120000 || CC_IS_CLANG
2158	select DEBUG_FS
2159	select OBJTOOL if HAVE_NOINSTR_HACK
2160	help
2161	  KCOV exposes kernel code coverage information in a form suitable
2162	  for coverage-guided fuzzing (randomized testing).
2163
2164	  For more details, see Documentation/dev-tools/kcov.rst.
2165
2166config KCOV_ENABLE_COMPARISONS
2167	bool "Enable comparison operands collection by KCOV"
2168	depends on KCOV
2169	depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2170	help
2171	  KCOV also exposes operands of every comparison in the instrumented
2172	  code along with operand sizes and PCs of the comparison instructions.
2173	  These operands can be used by fuzzing engines to improve the quality
2174	  of fuzzing coverage.
2175
2176config KCOV_INSTRUMENT_ALL
2177	bool "Instrument all code by default"
2178	depends on KCOV
2179	default y
2180	help
2181	  If you are doing generic system call fuzzing (like e.g. syzkaller),
2182	  then you will want to instrument the whole kernel and you should
2183	  say y here. If you are doing more targeted fuzzing (like e.g.
2184	  filesystem fuzzing with AFL) then you will want to enable coverage
2185	  for more specific subsets of files, and should say n here.
2186
2187config KCOV_IRQ_AREA_SIZE
2188	hex "Size of interrupt coverage collection area in words"
2189	depends on KCOV
2190	default 0x40000
2191	help
2192	  KCOV uses preallocated per-cpu areas to collect coverage from
2193	  soft interrupts. This specifies the size of those areas in the
2194	  number of unsigned long words.
2195
2196config KCOV_SELFTEST
2197	bool "Perform short selftests on boot"
2198	depends on KCOV
2199	help
2200	  Run short KCOV coverage collection selftests on boot.
2201	  On test failure, causes the kernel to panic. Recommended to be
2202	  enabled, ensuring critical functionality works as intended.
2203
2204menuconfig RUNTIME_TESTING_MENU
2205	bool "Runtime Testing"
2206	default y
2207
2208if RUNTIME_TESTING_MENU
2209
2210config TEST_DHRY
2211	tristate "Dhrystone benchmark test"
2212	help
2213	  Enable this to include the Dhrystone 2.1 benchmark.  This test
2214	  calculates the number of Dhrystones per second, and the number of
2215	  DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided
2216	  by 1757 (the number of Dhrystones per second obtained on the VAX
2217	  11/780, nominally a 1 MIPS machine).
2218
2219	  To run the benchmark, it needs to be enabled explicitly, either from
2220	  the kernel command line (when built-in), or from userspace (when
2221	  built-in or modular).
2222
2223	  Run once during kernel boot:
2224
2225	      test_dhry.run
2226
2227	  Set number of iterations from kernel command line:
2228
2229	      test_dhry.iterations=<n>
2230
2231	  Set number of iterations from userspace:
2232
2233	      echo <n> > /sys/module/test_dhry/parameters/iterations
2234
2235	  Trigger manual run from userspace:
2236
2237	      echo y > /sys/module/test_dhry/parameters/run
2238
2239	  If the number of iterations is <= 0, the test will devise a suitable
2240	  number of iterations (test runs for at least 2s) automatically.
2241	  This process takes ca. 4s.
2242
2243	  If unsure, say N.
2244
2245config LKDTM
2246	tristate "Linux Kernel Dump Test Tool Module"
2247	depends on DEBUG_FS
2248	help
2249	This module enables testing of the different dumping mechanisms by
2250	inducing system failures at predefined crash points.
2251	If you don't need it: say N
2252	Choose M here to compile this code as a module. The module will be
2253	called lkdtm.
2254
2255	Documentation on how to use the module can be found in
2256	Documentation/fault-injection/provoke-crashes.rst
2257
2258config CPUMASK_KUNIT_TEST
2259	tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2260	depends on KUNIT
2261	default KUNIT_ALL_TESTS
2262	help
2263	  Enable to turn on cpumask tests, running at boot or module load time.
2264
2265	  For more information on KUnit and unit tests in general, please refer
2266	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2267
2268	  If unsure, say N.
2269
2270config TEST_LIST_SORT
2271	tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2272	depends on KUNIT
2273	default KUNIT_ALL_TESTS
2274	help
2275	  Enable this to turn on 'list_sort()' function test. This test is
2276	  executed only once during system boot (so affects only boot time),
2277	  or at module load time.
2278
2279	  If unsure, say N.
2280
2281config TEST_SORT
2282	tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2283	depends on KUNIT
2284	default KUNIT_ALL_TESTS
2285	help
2286	  This option enables the self-test function of 'sort()' at boot,
2287	  or at module load time.
2288
2289	  If unsure, say N.
2290
2291config TEST_DIV64
2292	tristate "64bit/32bit division and modulo test"
2293	depends on DEBUG_KERNEL || m
2294	help
2295	  Enable this to turn on 'do_div()' function test. This test is
2296	  executed only once during system boot (so affects only boot time),
2297	  or at module load time.
2298
2299	  If unsure, say N.
2300
2301config TEST_MULDIV64
2302	tristate "mul_u64_u64_div_u64() test"
2303	depends on DEBUG_KERNEL || m
2304	help
2305	  Enable this to turn on 'mul_u64_u64_div_u64()' function test.
2306	  This test is executed only once during system boot (so affects
2307	  only boot time), or at module load time.
2308
2309	  If unsure, say N.
2310
2311config TEST_IOV_ITER
2312	tristate "Test iov_iter operation" if !KUNIT_ALL_TESTS
2313	depends on KUNIT
2314	depends on MMU
2315	default KUNIT_ALL_TESTS
2316	help
2317	  Enable this to turn on testing of the operation of the I/O iterator
2318	  (iov_iter). This test is executed only once during system boot (so
2319	  affects only boot time), or at module load time.
2320
2321	  If unsure, say N.
2322
2323config KPROBES_SANITY_TEST
2324	tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2325	depends on DEBUG_KERNEL
2326	depends on KPROBES
2327	depends on KUNIT
2328	select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2329	default KUNIT_ALL_TESTS
2330	help
2331	  This option provides for testing basic kprobes functionality on
2332	  boot. Samples of kprobe and kretprobe are inserted and
2333	  verified for functionality.
2334
2335	  Say N if you are unsure.
2336
2337config FPROBE_SANITY_TEST
2338	bool "Self test for fprobe"
2339	depends on DEBUG_KERNEL
2340	depends on FPROBE
2341	depends on KUNIT=y
2342	help
2343	  This option will enable testing the fprobe when the system boot.
2344	  A series of tests are made to verify that the fprobe is functioning
2345	  properly.
2346
2347	  Say N if you are unsure.
2348
2349config BACKTRACE_SELF_TEST
2350	tristate "Self test for the backtrace code"
2351	depends on DEBUG_KERNEL
2352	help
2353	  This option provides a kernel module that can be used to test
2354	  the kernel stack backtrace code. This option is not useful
2355	  for distributions or general kernels, but only for kernel
2356	  developers working on architecture code.
2357
2358	  Note that if you want to also test saved backtraces, you will
2359	  have to enable STACKTRACE as well.
2360
2361	  Say N if you are unsure.
2362
2363config TEST_REF_TRACKER
2364	tristate "Self test for reference tracker"
2365	depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2366	select REF_TRACKER
2367	help
2368	  This option provides a kernel module performing tests
2369	  using reference tracker infrastructure.
2370
2371	  Say N if you are unsure.
2372
2373config RBTREE_TEST
2374	tristate "Red-Black tree test"
2375	depends on DEBUG_KERNEL
2376	help
2377	  A benchmark measuring the performance of the rbtree library.
2378	  Also includes rbtree invariant checks.
2379
2380config REED_SOLOMON_TEST
2381	tristate "Reed-Solomon library test"
2382	depends on DEBUG_KERNEL || m
2383	select REED_SOLOMON
2384	select REED_SOLOMON_ENC16
2385	select REED_SOLOMON_DEC16
2386	help
2387	  This option enables the self-test function of rslib at boot,
2388	  or at module load time.
2389
2390	  If unsure, say N.
2391
2392config INTERVAL_TREE_TEST
2393	tristate "Interval tree test"
2394	depends on DEBUG_KERNEL
2395	select INTERVAL_TREE
2396	help
2397	  A benchmark measuring the performance of the interval tree library
2398
2399config PERCPU_TEST
2400	tristate "Per cpu operations test"
2401	depends on m && DEBUG_KERNEL
2402	help
2403	  Enable this option to build test module which validates per-cpu
2404	  operations.
2405
2406	  If unsure, say N.
2407
2408config ATOMIC64_SELFTEST
2409	tristate "Perform an atomic64_t self-test"
2410	help
2411	  Enable this option to test the atomic64_t functions at boot or
2412	  at module load time.
2413
2414	  If unsure, say N.
2415
2416config ASYNC_RAID6_TEST
2417	tristate "Self test for hardware accelerated raid6 recovery"
2418	depends on ASYNC_RAID6_RECOV
2419	select ASYNC_MEMCPY
2420	help
2421	  This is a one-shot self test that permutes through the
2422	  recovery of all the possible two disk failure scenarios for a
2423	  N-disk array.  Recovery is performed with the asynchronous
2424	  raid6 recovery routines, and will optionally use an offload
2425	  engine if one is available.
2426
2427	  If unsure, say N.
2428
2429config TEST_HEXDUMP
2430	tristate "Test functions located in the hexdump module at runtime"
2431
2432config PRINTF_KUNIT_TEST
2433	tristate "KUnit test printf() family of functions at runtime" if !KUNIT_ALL_TESTS
2434	depends on KUNIT
2435	default KUNIT_ALL_TESTS
2436	help
2437	  Enable this option to test the printf functions at runtime.
2438
2439	  If unsure, say N.
2440
2441config SCANF_KUNIT_TEST
2442	tristate "KUnit test scanf() family of functions at runtime" if !KUNIT_ALL_TESTS
2443	depends on KUNIT
2444	default KUNIT_ALL_TESTS
2445	help
2446	  Enable this option to test the scanf functions at runtime.
2447
2448	  If unsure, say N.
2449
2450config SEQ_BUF_KUNIT_TEST
2451	tristate "KUnit test for seq_buf" if !KUNIT_ALL_TESTS
2452	depends on KUNIT
2453	default KUNIT_ALL_TESTS
2454	help
2455	  This builds unit tests for the seq_buf library.
2456
2457	  If unsure, say N.
2458
2459config STRING_KUNIT_TEST
2460	tristate "KUnit test string functions at runtime" if !KUNIT_ALL_TESTS
2461	depends on KUNIT
2462	default KUNIT_ALL_TESTS
2463
2464config STRING_HELPERS_KUNIT_TEST
2465	tristate "KUnit test string helpers at runtime" if !KUNIT_ALL_TESTS
2466	depends on KUNIT
2467	default KUNIT_ALL_TESTS
2468
2469config FFS_KUNIT_TEST
2470	tristate "KUnit test ffs-family functions at runtime" if !KUNIT_ALL_TESTS
2471	depends on KUNIT
2472	default KUNIT_ALL_TESTS
2473	help
2474	  This builds KUnit tests for ffs-family bit manipulation functions
2475	  including ffs(), __ffs(), fls(), __fls(), fls64(), and __ffs64().
2476
2477	  These tests validate mathematical correctness, edge case handling,
2478	  and cross-architecture consistency of bit scanning functions.
2479
2480	  For more information on KUnit and unit tests in general,
2481	  please refer to Documentation/dev-tools/kunit/.
2482
2483config TEST_KSTRTOX
2484	tristate "Test kstrto*() family of functions at runtime"
2485
2486config TEST_BITMAP
2487	tristate "Test bitmap_*() family of functions at runtime"
2488	help
2489	  Enable this option to test the bitmap functions at boot.
2490
2491	  If unsure, say N.
2492
2493config TEST_XARRAY
2494	tristate "Test the XArray code at runtime"
2495
2496config TEST_MAPLE_TREE
2497	tristate "Test the Maple Tree code at runtime or module load"
2498	help
2499	  Enable this option to test the maple tree code functions at boot, or
2500	  when the module is loaded. Enable "Debug Maple Trees" will enable
2501	  more verbose output on failures.
2502
2503	  If unsure, say N.
2504
2505config TEST_RHASHTABLE
2506	tristate "Perform selftest on resizable hash table"
2507	help
2508	  Enable this option to test the rhashtable functions at boot.
2509
2510	  If unsure, say N.
2511
2512config TEST_IDA
2513	tristate "Perform selftest on IDA functions"
2514
2515config TEST_MISC_MINOR
2516	bool "miscdevice KUnit test" if !KUNIT_ALL_TESTS
2517	depends on KUNIT=y
2518	default KUNIT_ALL_TESTS
2519	help
2520	  Kunit test for miscdevice API, specially its behavior in respect to
2521	  static and dynamic minor numbers.
2522
2523	  KUnit tests run during boot and output the results to the debug log
2524	  in TAP format (https://testanything.org/). Only useful for kernel devs
2525	  running the KUnit test harness, and not intended for inclusion into a
2526	  production build.
2527
2528	  For more information on KUnit and unit tests in general please refer
2529	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2530
2531	  If unsure, say N.
2532
2533config TEST_PARMAN
2534	tristate "Perform selftest on priority array manager"
2535	depends on PARMAN
2536	help
2537	  Enable this option to test priority array manager on boot
2538	  (or module load).
2539
2540	  If unsure, say N.
2541
2542config TEST_IRQ_TIMINGS
2543	bool "IRQ timings selftest"
2544	depends on IRQ_TIMINGS
2545	help
2546	  Enable this option to test the irq timings code on boot.
2547
2548	  If unsure, say N.
2549
2550config TEST_LKM
2551	tristate "Test module loading with 'hello world' module"
2552	depends on m
2553	help
2554	  This builds the "test_module" module that emits "Hello, world"
2555	  on printk when loaded. It is designed to be used for basic
2556	  evaluation of the module loading subsystem (for example when
2557	  validating module verification). It lacks any extra dependencies,
2558	  and will not normally be loaded by the system unless explicitly
2559	  requested by name.
2560
2561	  If unsure, say N.
2562
2563config TEST_BITOPS
2564	tristate "Test module for compilation of bitops operations"
2565	help
2566	  This builds the "test_bitops" module that is much like the
2567	  TEST_LKM module except that it does a basic exercise of the
2568	  set/clear_bit macros and get_count_order/long to make sure there are
2569	  no compiler warnings from C=1 sparse checker or -Wextra
2570	  compilations. It has no dependencies and doesn't run or load unless
2571	  explicitly requested by name.  for example: modprobe test_bitops.
2572
2573	  If unsure, say N.
2574
2575config TEST_VMALLOC
2576	tristate "Test module for stress/performance analysis of vmalloc allocator"
2577	default n
2578	depends on MMU
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 FIND_BIT_BENCHMARK_RUST
2609	tristate "Test find_bit functions in Rust"
2610	depends on RUST
2611	help
2612	  This builds the "find_bit_benchmark_rust" module. It is a micro
2613          benchmark that measures the performance of Rust functions that
2614          correspond to the find_*_bit() operations in C. It follows the
2615          FIND_BIT_BENCHMARK closely but will in general not yield same
2616          numbers due to extra bounds checks and overhead of foreign
2617          function calls.
2618
2619	  If unsure, say N.
2620
2621config TEST_FIRMWARE
2622	tristate "Test firmware loading via userspace interface"
2623	depends on FW_LOADER
2624	help
2625	  This builds the "test_firmware" module that creates a userspace
2626	  interface for testing firmware loading. This can be used to
2627	  control the triggering of firmware loading without needing an
2628	  actual firmware-using device. The contents can be rechecked by
2629	  userspace.
2630
2631	  If unsure, say N.
2632
2633config TEST_SYSCTL
2634	tristate "sysctl test driver"
2635	depends on PROC_SYSCTL
2636	help
2637	  This builds the "test_sysctl" module. This driver enables to test the
2638	  proc sysctl interfaces available to drivers safely without affecting
2639	  production knobs which might alter system functionality.
2640
2641	  If unsure, say N.
2642
2643config BITFIELD_KUNIT
2644	tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2645	depends on KUNIT
2646	default KUNIT_ALL_TESTS
2647	help
2648	  Enable this option to test the bitfield functions at boot.
2649
2650	  KUnit tests run during boot and output the results to the debug log
2651	  in TAP format (http://testanything.org/). Only useful for kernel devs
2652	  running the KUnit test harness, and not intended for inclusion into a
2653	  production build.
2654
2655	  For more information on KUnit and unit tests in general please refer
2656	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2657
2658	  If unsure, say N.
2659
2660config CHECKSUM_KUNIT
2661	tristate "KUnit test checksum functions at runtime" if !KUNIT_ALL_TESTS
2662	depends on KUNIT
2663	default KUNIT_ALL_TESTS
2664	help
2665	  Enable this option to test the checksum functions at boot.
2666
2667	  KUnit tests run during boot and output the results to the debug log
2668	  in TAP format (http://testanything.org/). Only useful for kernel devs
2669	  running the KUnit test harness, and not intended for inclusion into a
2670	  production build.
2671
2672	  For more information on KUnit and unit tests in general please refer
2673	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2674
2675	  If unsure, say N.
2676
2677config UTIL_MACROS_KUNIT
2678	tristate "KUnit test util_macros.h functions at runtime" if !KUNIT_ALL_TESTS
2679	depends on KUNIT
2680	default KUNIT_ALL_TESTS
2681	help
2682	  Enable this option to test the util_macros.h function at boot.
2683
2684	  KUnit tests run during boot and output the results to the debug log
2685	  in TAP format (http://testanything.org/). Only useful for kernel devs
2686	  running the KUnit test harness, and not intended for inclusion into a
2687	  production build.
2688
2689	  For more information on KUnit and unit tests in general please refer
2690	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2691
2692	  If unsure, say N.
2693
2694config HASH_KUNIT_TEST
2695	tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2696	depends on KUNIT
2697	default KUNIT_ALL_TESTS
2698	help
2699	  Enable this option to test the kernel's string (<linux/stringhash.h>), and
2700	  integer (<linux/hash.h>) hash functions on boot.
2701
2702	  KUnit tests run during boot and output the results to the debug log
2703	  in TAP format (https://testanything.org/). Only useful for kernel devs
2704	  running the KUnit test harness, and not intended for inclusion into a
2705	  production build.
2706
2707	  For more information on KUnit and unit tests in general please refer
2708	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2709
2710	  This is intended to help people writing architecture-specific
2711	  optimized versions. If unsure, say N.
2712
2713config RESOURCE_KUNIT_TEST
2714	tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2715	depends on KUNIT
2716	default KUNIT_ALL_TESTS
2717	select GET_FREE_REGION
2718	help
2719	  This builds the resource API unit test.
2720	  Tests the logic of API provided by resource.c and ioport.h.
2721	  For more information on KUnit and unit tests in general please refer
2722	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2723
2724	  If unsure, say N.
2725
2726config SYSCTL_KUNIT_TEST
2727	tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2728	depends on KUNIT
2729	default KUNIT_ALL_TESTS
2730	help
2731	  This builds the proc sysctl unit test, which runs on boot.
2732	  Tests the API contract and implementation correctness of sysctl.
2733	  For more information on KUnit and unit tests in general please refer
2734	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2735
2736	  If unsure, say N.
2737
2738config KFIFO_KUNIT_TEST
2739	tristate "KUnit Test for the generic kernel FIFO implementation" if !KUNIT_ALL_TESTS
2740	depends on KUNIT
2741	default KUNIT_ALL_TESTS
2742	help
2743	  This builds the generic FIFO implementation KUnit test suite.
2744	  It tests that the API and basic functionality of the kfifo type
2745	  and associated macros.
2746
2747	  For more information on KUnit and unit tests in general please refer
2748	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2749
2750	  If unsure, say N.
2751
2752config LIST_KUNIT_TEST
2753	tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2754	depends on KUNIT
2755	default KUNIT_ALL_TESTS
2756	help
2757	  This builds the linked list KUnit test suite.
2758	  It tests that the API and basic functionality of the list_head type
2759	  and associated macros.
2760
2761	  KUnit tests run during boot and output the results to the debug log
2762	  in TAP format (https://testanything.org/). Only useful for kernel devs
2763	  running the KUnit test harness, and not intended for inclusion into a
2764	  production build.
2765
2766	  For more information on KUnit and unit tests in general please refer
2767	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2768
2769	  If unsure, say N.
2770
2771config HASHTABLE_KUNIT_TEST
2772	tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS
2773	depends on KUNIT
2774	default KUNIT_ALL_TESTS
2775	help
2776	  This builds the hashtable KUnit test suite.
2777	  It tests the basic functionality of the API defined in
2778	  include/linux/hashtable.h. For more information on KUnit and
2779	  unit tests in general please refer to the KUnit documentation
2780	  in Documentation/dev-tools/kunit/.
2781
2782	  If unsure, say N.
2783
2784config LINEAR_RANGES_TEST
2785	tristate "KUnit test for linear_ranges"
2786	depends on KUNIT
2787	select LINEAR_RANGES
2788	help
2789	  This builds the linear_ranges unit test, which runs on boot.
2790	  Tests the linear_ranges logic correctness.
2791	  For more information on KUnit and unit tests in general please refer
2792	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2793
2794	  If unsure, say N.
2795
2796config CMDLINE_KUNIT_TEST
2797	tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2798	depends on KUNIT
2799	default KUNIT_ALL_TESTS
2800	help
2801	  This builds the cmdline API unit test.
2802	  Tests the logic of API provided by cmdline.c.
2803	  For more information on KUnit and unit tests in general please refer
2804	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2805
2806	  If unsure, say N.
2807
2808config BASE64_KUNIT
2809	tristate "KUnit test for base64 decoding and encoding" if !KUNIT_ALL_TESTS
2810	depends on KUNIT
2811	default KUNIT_ALL_TESTS
2812	help
2813	  This builds the base64 unit tests.
2814
2815	  The tests cover the encoding and decoding logic of Base64 functions
2816	  in the kernel.
2817	  In addition to correctness checks, simple performance benchmarks
2818	  for both encoding and decoding are also included.
2819
2820	  For more information on KUnit and unit tests in general please refer
2821	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2822
2823	  If unsure, say N.
2824
2825config BITS_TEST
2826	tristate "KUnit test for bit functions and macros" if !KUNIT_ALL_TESTS
2827	depends on KUNIT
2828	default KUNIT_ALL_TESTS
2829	help
2830	  This builds the bits unit test.
2831	  Tests the logic of macros defined in bits.h.
2832	  For more information on KUnit and unit tests in general please refer
2833	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2834
2835	  If unsure, say N.
2836
2837config SLUB_KUNIT_TEST
2838	tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2839	depends on SLUB_DEBUG && KUNIT
2840	default KUNIT_ALL_TESTS
2841	help
2842	  This builds SLUB allocator unit test.
2843	  Tests SLUB cache debugging functionality.
2844	  For more information on KUnit and unit tests in general please refer
2845	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2846
2847	  If unsure, say N.
2848
2849config RATIONAL_KUNIT_TEST
2850	tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2851	depends on KUNIT && RATIONAL
2852	default KUNIT_ALL_TESTS
2853	help
2854	  This builds the rational math unit test.
2855	  For more information on KUnit and unit tests in general please refer
2856	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2857
2858	  If unsure, say N.
2859
2860config MEMCPY_KUNIT_TEST
2861	tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2862	depends on KUNIT
2863	default KUNIT_ALL_TESTS
2864	help
2865	  Builds unit tests for memcpy(), memmove(), and memset() functions.
2866	  For more information on KUnit and unit tests in general please refer
2867	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2868
2869	  If unsure, say N.
2870
2871config MIN_HEAP_KUNIT_TEST
2872	tristate "Min heap test" if !KUNIT_ALL_TESTS
2873	depends on KUNIT
2874	default KUNIT_ALL_TESTS
2875	help
2876	  This option enables the KUnit test suite for the min heap library
2877	  which provides functions for creating and managing min heaps.
2878	  The test suite checks the functionality of the min heap library.
2879
2880	  If unsure, say N
2881
2882config IS_SIGNED_TYPE_KUNIT_TEST
2883	tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2884	depends on KUNIT
2885	default KUNIT_ALL_TESTS
2886	help
2887	  Builds unit tests for the is_signed_type() macro.
2888
2889	  For more information on KUnit and unit tests in general please refer
2890	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2891
2892	  If unsure, say N.
2893
2894config OVERFLOW_KUNIT_TEST
2895	tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2896	depends on KUNIT
2897	default KUNIT_ALL_TESTS
2898	help
2899	  Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2900	  related functions.
2901
2902	  For more information on KUnit and unit tests in general please refer
2903	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2904
2905	  If unsure, say N.
2906
2907config RANDSTRUCT_KUNIT_TEST
2908	tristate "Test randstruct structure layout randomization at runtime" if !KUNIT_ALL_TESTS
2909	depends on KUNIT
2910	default KUNIT_ALL_TESTS
2911	help
2912	  Builds unit tests for the checking CONFIG_RANDSTRUCT=y, which
2913	  randomizes structure layouts.
2914
2915config STACKINIT_KUNIT_TEST
2916	tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2917	depends on KUNIT
2918	default KUNIT_ALL_TESTS
2919	help
2920	  Test if the kernel is zero-initializing stack variables and
2921	  padding. Coverage is controlled by compiler flags,
2922	  CONFIG_INIT_STACK_ALL_PATTERN or CONFIG_INIT_STACK_ALL_ZERO.
2923
2924config FORTIFY_KUNIT_TEST
2925	tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2926	depends on KUNIT
2927	default KUNIT_ALL_TESTS
2928	help
2929	  Builds unit tests for checking internals of FORTIFY_SOURCE as used
2930	  by the str*() and mem*() family of functions. For testing runtime
2931	  traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2932
2933config LONGEST_SYM_KUNIT_TEST
2934	tristate "Test the longest symbol possible" if !KUNIT_ALL_TESTS
2935	depends on KUNIT && KPROBES
2936	depends on !PREFIX_SYMBOLS && !CFI && !GCOV_KERNEL
2937	default KUNIT_ALL_TESTS
2938	help
2939	  Tests the longest symbol possible
2940
2941	  If unsure, say N.
2942
2943config HW_BREAKPOINT_KUNIT_TEST
2944	bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2945	depends on HAVE_HW_BREAKPOINT
2946	depends on KUNIT=y
2947	default KUNIT_ALL_TESTS
2948	help
2949	  Tests for hw_breakpoint constraints accounting.
2950
2951	  If unsure, say N.
2952
2953config SIPHASH_KUNIT_TEST
2954	tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2955	depends on KUNIT
2956	default KUNIT_ALL_TESTS
2957	help
2958	  Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2959	  functions on boot (or module load).
2960
2961	  This is intended to help people writing architecture-specific
2962	  optimized versions.  If unsure, say N.
2963
2964config USERCOPY_KUNIT_TEST
2965	tristate "KUnit Test for user/kernel boundary protections"
2966	depends on KUNIT
2967	default KUNIT_ALL_TESTS
2968	help
2969	  This builds the "usercopy_kunit" module that runs sanity checks
2970	  on the copy_to/from_user infrastructure, making sure basic
2971	  user/kernel boundary testing is working.
2972
2973config BLACKHOLE_DEV_KUNIT_TEST
2974	tristate "Test blackhole netdev functionality" if !KUNIT_ALL_TESTS
2975	depends on NET
2976	depends on KUNIT
2977	default KUNIT_ALL_TESTS
2978	help
2979	  This builds the "blackhole_dev_kunit" module that validates the
2980	  data path through this blackhole netdev.
2981
2982	  If unsure, say N.
2983
2984config TEST_UDELAY
2985	tristate "udelay test driver"
2986	help
2987	  This builds the "udelay_test" module that helps to make sure
2988	  that udelay() is working properly.
2989
2990	  If unsure, say N.
2991
2992config TEST_STATIC_KEYS
2993	tristate "Test static keys"
2994	depends on m
2995	help
2996	  Test the static key interfaces.
2997
2998	  If unsure, say N.
2999
3000config TEST_DYNAMIC_DEBUG
3001	tristate "Test DYNAMIC_DEBUG"
3002	depends on DYNAMIC_DEBUG
3003	help
3004	  This module registers a tracer callback to count enabled
3005	  pr_debugs in a 'do_debugging' function, then alters their
3006	  enablements, calls the function, and compares counts.
3007
3008	  If unsure, say N.
3009
3010config TEST_KMOD
3011	tristate "kmod stress tester"
3012	depends on m
3013	select TEST_LKM
3014	help
3015	  Test the kernel's module loading mechanism: kmod. kmod implements
3016	  support to load modules using the Linux kernel's usermode helper.
3017	  This test provides a series of tests against kmod.
3018
3019	  Although technically you can either build test_kmod as a module or
3020	  into the kernel we disallow building it into the kernel since
3021	  it stress tests request_module() and this will very likely cause
3022	  some issues by taking over precious threads available from other
3023	  module load requests, ultimately this could be fatal.
3024
3025	  To run tests run:
3026
3027	  tools/testing/selftests/kmod/kmod.sh --help
3028
3029	  If unsure, say N.
3030
3031config TEST_RUNTIME
3032	bool
3033
3034config TEST_RUNTIME_MODULE
3035	bool
3036
3037config TEST_KALLSYMS
3038	tristate "module kallsyms find_symbol() test"
3039	depends on m
3040	select TEST_RUNTIME
3041	select TEST_RUNTIME_MODULE
3042	select TEST_KALLSYMS_A
3043	select TEST_KALLSYMS_B
3044	select TEST_KALLSYMS_C
3045	select TEST_KALLSYMS_D
3046	help
3047	  This allows us to stress test find_symbol() through the kallsyms
3048	  used to place symbols on the kernel ELF kallsyms and modules kallsyms
3049	  where we place kernel symbols such as exported symbols.
3050
3051	  We have four test modules:
3052
3053	  A: has KALLSYSMS_NUMSYMS exported symbols
3054	  B: uses one of A's symbols
3055	  C: adds KALLSYMS_SCALE_FACTOR * KALLSYSMS_NUMSYMS exported
3056	  D: adds 2 * the symbols than C
3057
3058	  We stress test find_symbol() through two means:
3059
3060	  1) Upon load of B it will trigger simplify_symbols() to look for the
3061	  one symbol it uses from the module A with tons of symbols. This is an
3062	  indirect way for us to have B call resolve_symbol_wait() upon module
3063	  load. This will eventually call find_symbol() which will eventually
3064	  try to find the symbols used with find_exported_symbol_in_section().
3065	  find_exported_symbol_in_section() uses bsearch() so a binary search
3066	  for each symbol. Binary search will at worst be O(log(n)) so the
3067	  larger TEST_MODULE_KALLSYSMS the worse the search.
3068
3069	  2) The selftests should load C first, before B. Upon B's load towards
3070	  the end right before we call module B's init routine we get
3071	  complete_formation() called on the module. That will first check
3072	  for duplicate symbols with the call to verify_exported_symbols().
3073	  That is when we'll force iteration on module C's insane symbol list.
3074	  Since it has 10 * KALLSYMS_NUMSYMS it means we can first test
3075	  just loading B without C. The amount of time it takes to load C Vs
3076	  B can give us an idea of the impact growth of the symbol space and
3077	  give us projection. Module A only uses one symbol from B so to allow
3078	  this scaling in module C to be proportional, if it used more symbols
3079	  then the first test would be doing more and increasing just the
3080	  search space would be slightly different. The last module, module D
3081	  will just increase the search space by twice the number of symbols in
3082	  C so to allow for full projects.
3083
3084	  tools/testing/selftests/module/find_symbol.sh
3085
3086	  The current defaults will incur a build delay of about 7 minutes
3087	  on an x86_64 with only 8 cores. Enable this only if you want to
3088	  stress test find_symbol() with thousands of symbols. At the same
3089	  time this is also useful to test building modules with thousands of
3090	  symbols, and if BTF is enabled this also stress tests adding BTF
3091	  information for each module. Currently enabling many more symbols
3092	  will segfault the build system.
3093
3094	  If unsure, say N.
3095
3096if TEST_KALLSYMS
3097
3098config TEST_KALLSYMS_A
3099	tristate
3100	depends on m
3101
3102config TEST_KALLSYMS_B
3103	tristate
3104	depends on m
3105
3106config TEST_KALLSYMS_C
3107	tristate
3108	depends on m
3109
3110config TEST_KALLSYMS_D
3111	tristate
3112	depends on m
3113
3114choice
3115	prompt "Kallsym test range"
3116	default TEST_KALLSYMS_LARGE
3117	help
3118	  Selecting something other than "Fast" will enable tests which slow
3119	  down the build and may crash your build.
3120
3121config TEST_KALLSYMS_FAST
3122	bool "Fast builds"
3123	help
3124	  You won't really be testing kallsysms, so this just helps fast builds
3125	  when allmodconfig is used..
3126
3127config TEST_KALLSYMS_LARGE
3128	bool "Enable testing kallsyms with large exports"
3129	help
3130	  This will enable larger number of symbols. This will slow down
3131	  your build considerably.
3132
3133config TEST_KALLSYMS_MAX
3134	bool "Known kallsysms limits"
3135	help
3136	  This will enable exports to the point we know we'll start crashing
3137	  builds.
3138
3139endchoice
3140
3141config TEST_KALLSYMS_NUMSYMS
3142	int "test kallsyms number of symbols"
3143	range 2 10000
3144	default 2 if TEST_KALLSYMS_FAST
3145	default 100 if TEST_KALLSYMS_LARGE
3146	default 10000 if TEST_KALLSYMS_MAX
3147	help
3148	  The number of symbols to create on TEST_KALLSYMS_A, only one of which
3149	  module TEST_KALLSYMS_B will use. This also will be used
3150	  for how many symbols TEST_KALLSYMS_C will have, scaled up by
3151	  TEST_KALLSYMS_SCALE_FACTOR. Note that setting this to 10,000 will
3152	  trigger a segfault today, don't use anything close to it unless
3153	  you are aware that this should not be used for automated build tests.
3154
3155config TEST_KALLSYMS_SCALE_FACTOR
3156	int "test kallsyms scale factor"
3157	default 8
3158	help
3159	  How many more unusued symbols will TEST_KALLSYSMS_C have than
3160	  TEST_KALLSYMS_A. If 8, then module C will have 8 * syms
3161	  than module A. Then TEST_KALLSYMS_D will have double the amount
3162	  of symbols than C so to allow projections.
3163
3164endif # TEST_KALLSYMS
3165
3166config TEST_DEBUG_VIRTUAL
3167	tristate "Test CONFIG_DEBUG_VIRTUAL feature"
3168	depends on DEBUG_VIRTUAL
3169	help
3170	  Test the kernel's ability to detect incorrect calls to
3171	  virt_to_phys() done against the non-linear part of the
3172	  kernel's virtual address map.
3173
3174	  If unsure, say N.
3175
3176config TEST_MEMCAT_P
3177	tristate "Test memcat_p() helper function"
3178	help
3179	  Test the memcat_p() helper for correctly merging two
3180	  pointer arrays together.
3181
3182	  If unsure, say N.
3183
3184config TEST_OBJAGG
3185	tristate "Perform selftest on object aggreration manager"
3186	default n
3187	depends on OBJAGG
3188	help
3189	  Enable this option to test object aggregation manager on boot
3190	  (or module load).
3191
3192config TEST_MEMINIT
3193	tristate "Test heap/page initialization"
3194	help
3195	  Test if the kernel is zero-initializing heap and page allocations.
3196	  This can be useful to test init_on_alloc and init_on_free features.
3197
3198	  If unsure, say N.
3199
3200config TEST_HMM
3201	tristate "Test HMM (Heterogeneous Memory Management)"
3202	depends on TRANSPARENT_HUGEPAGE
3203	depends on DEVICE_PRIVATE
3204	select HMM_MIRROR
3205	select MMU_NOTIFIER
3206	help
3207	  This is a pseudo device driver solely for testing HMM.
3208	  Say M here if you want to build the HMM test module.
3209	  Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
3210
3211	  If unsure, say N.
3212
3213config TEST_FREE_PAGES
3214	tristate "Test freeing pages"
3215	help
3216	  Test that a memory leak does not occur due to a race between
3217	  freeing a block of pages and a speculative page reference.
3218	  Loading this module is safe if your kernel has the bug fixed.
3219	  If the bug is not fixed, it will leak gigabytes of memory and
3220	  probably OOM your system.
3221
3222config TEST_FPU
3223	tristate "Test floating point operations in kernel space"
3224	depends on ARCH_HAS_KERNEL_FPU_SUPPORT && !KCOV_INSTRUMENT_ALL
3225	help
3226	  Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
3227	  which will trigger a sequence of floating point operations. This is used
3228	  for self-testing floating point control register setting in
3229	  kernel_fpu_begin().
3230
3231	  If unsure, say N.
3232
3233config TEST_CLOCKSOURCE_WATCHDOG
3234	tristate "Test clocksource watchdog in kernel space"
3235	depends on CLOCKSOURCE_WATCHDOG
3236	help
3237	  Enable this option to create a kernel module that will trigger
3238	  a test of the clocksource watchdog.  This module may be loaded
3239	  via modprobe or insmod in which case it will run upon being
3240	  loaded, or it may be built in, in which case it will run
3241	  shortly after boot.
3242
3243	  If unsure, say N.
3244
3245config TEST_OBJPOOL
3246	tristate "Test module for correctness and stress of objpool"
3247	default n
3248	depends on m && DEBUG_KERNEL
3249	help
3250	  This builds the "test_objpool" module that should be used for
3251	  correctness verification and concurrent testings of objects
3252	  allocation and reclamation.
3253
3254	  If unsure, say N.
3255
3256config TEST_KEXEC_HANDOVER
3257	bool "Test for Kexec HandOver"
3258	default n
3259	depends on KEXEC_HANDOVER
3260	help
3261	  This option enables test for Kexec HandOver (KHO).
3262	  The test consists of two parts: saving kernel data before kexec and
3263	  restoring the data after kexec and verifying that it was properly
3264	  handed over. This test module creates and saves data on the boot of
3265	  the first kernel and restores and verifies the data on the boot of
3266	  kexec'ed kernel.
3267
3268	  For detailed documentation about KHO, see Documentation/core-api/kho.
3269
3270	  To run the test run:
3271
3272	  tools/testing/selftests/kho/vmtest.sh -h
3273
3274	  If unsure, say N.
3275
3276config RATELIMIT_KUNIT_TEST
3277	tristate "KUnit Test for correctness and stress of ratelimit" if !KUNIT_ALL_TESTS
3278	depends on KUNIT
3279	default KUNIT_ALL_TESTS
3280	help
3281	  This builds the "test_ratelimit" module that should be used
3282	  for correctness verification and concurrent testings of rate
3283	  limiting.
3284
3285	  If unsure, say N.
3286
3287config UUID_KUNIT_TEST
3288	tristate "KUnit test for UUID" if !KUNIT_ALL_TESTS
3289	depends on KUNIT
3290	default KUNIT_ALL_TESTS
3291	help
3292	  This option enables the KUnit test suite for the uuid library,
3293	  which provides functions for generating and parsing UUID and GUID.
3294	  The test suite checks parsing of UUID and GUID strings.
3295
3296	  If unsure, say N.
3297
3298config INT_POW_KUNIT_TEST
3299	tristate "Integer exponentiation (int_pow) test" if !KUNIT_ALL_TESTS
3300	depends on KUNIT
3301	default KUNIT_ALL_TESTS
3302	help
3303	  This option enables the KUnit test suite for the int_pow function,
3304	  which performs integer exponentiation. The test suite is designed to
3305	  verify that the implementation of int_pow correctly computes the power
3306	  of a given base raised to a given exponent.
3307
3308	  Enabling this option will include tests that check various scenarios
3309	  and edge cases to ensure the accuracy and reliability of the exponentiation
3310	  function.
3311
3312	  If unsure, say N
3313
3314config INT_SQRT_KUNIT_TEST
3315	tristate "Integer square root test" if !KUNIT_ALL_TESTS
3316	depends on KUNIT
3317	default KUNIT_ALL_TESTS
3318	help
3319	  This option enables the KUnit test suite for the int_sqrt() function,
3320	  which performs square root calculation. The test suite checks
3321	  various scenarios, including edge cases, to ensure correctness.
3322
3323	  Enabling this option will include tests that check various scenarios
3324	  and edge cases to ensure the accuracy and reliability of the square root
3325	  function.
3326
3327	  If unsure, say N
3328
3329config INT_LOG_KUNIT_TEST
3330        tristate "Integer log (int_log) test" if !KUNIT_ALL_TESTS
3331        depends on KUNIT
3332        default KUNIT_ALL_TESTS
3333        help
3334          This option enables the KUnit test suite for the int_log library, which
3335          provides two functions to compute the integer logarithm in base 2 and
3336          base 10, called respectively as intlog2 and intlog10.
3337
3338          If unsure, say N
3339
3340config GCD_KUNIT_TEST
3341	tristate "Greatest common divisor test" if !KUNIT_ALL_TESTS
3342	depends on KUNIT
3343	default KUNIT_ALL_TESTS
3344	help
3345	  This option enables the KUnit test suite for the gcd() function,
3346	  which computes the greatest common divisor of two numbers.
3347
3348	  This test suite verifies the correctness of gcd() across various
3349	  scenarios, including edge cases.
3350
3351	  If unsure, say N
3352
3353config PRIME_NUMBERS_KUNIT_TEST
3354	tristate "Prime number generator test" if !KUNIT_ALL_TESTS
3355	depends on KUNIT
3356	depends on PRIME_NUMBERS
3357	default KUNIT_ALL_TESTS
3358	help
3359	  This option enables the KUnit test suite for the {is,next}_prime_number
3360	  functions.
3361
3362	  Enabling this option will include tests that compare the prime number
3363	  generator functions against a brute force implementation.
3364
3365	  If unsure, say N
3366
3367config GLOB_KUNIT_TEST
3368	tristate "Glob matching test" if !KUNIT_ALL_TESTS
3369	depends on GLOB
3370	depends on KUNIT
3371	default KUNIT_ALL_TESTS
3372	help
3373	  Enable this option to test the glob functions at runtime.
3374
3375	  This test suite verifies the correctness of glob_match() across various
3376	  scenarios, including edge cases.
3377
3378	  If unsure, say N
3379
3380endif # RUNTIME_TESTING_MENU
3381
3382config ARCH_USE_MEMTEST
3383	bool
3384	help
3385	  An architecture should select this when it uses early_memtest()
3386	  during boot process.
3387
3388config MEMTEST
3389	bool "Memtest"
3390	depends on ARCH_USE_MEMTEST
3391	help
3392	  This option adds a kernel parameter 'memtest', which allows memtest
3393	  to be set and executed.
3394	        memtest=0, mean disabled; -- default
3395	        memtest=1, mean do 1 test pattern;
3396	        ...
3397	        memtest=17, mean do 17 test patterns.
3398	  If you are unsure how to answer this question, answer N.
3399
3400
3401
3402config HYPERV_TESTING
3403	bool "Microsoft Hyper-V driver testing"
3404	default n
3405	depends on HYPERV && DEBUG_FS
3406	help
3407	  Select this option to enable Hyper-V vmbus testing.
3408
3409endmenu # "Kernel Testing and Coverage"
3410
3411menu "Rust hacking"
3412
3413config RUST_DEBUG_ASSERTIONS
3414	bool "Debug assertions"
3415	depends on RUST
3416	help
3417	  Enables rustc's `-Cdebug-assertions` codegen option.
3418
3419	  This flag lets you turn `cfg(debug_assertions)` conditional
3420	  compilation on or off. This can be used to enable extra debugging
3421	  code in development but not in production. For example, it controls
3422	  the behavior of the standard library's `debug_assert!` macro.
3423
3424	  Note that this will apply to all Rust code, including `core`.
3425
3426	  If unsure, say N.
3427
3428config RUST_OVERFLOW_CHECKS
3429	bool "Overflow checks"
3430	default y
3431	depends on RUST
3432	help
3433	  Enables rustc's `-Coverflow-checks` codegen option.
3434
3435	  This flag allows you to control the behavior of runtime integer
3436	  overflow. When overflow-checks are enabled, a Rust panic will occur
3437	  on overflow.
3438
3439	  Note that this will apply to all Rust code, including `core`.
3440
3441	  If unsure, say Y.
3442
3443config RUST_BUILD_ASSERT_ALLOW
3444	bool "Allow unoptimized build-time assertions"
3445	depends on RUST
3446	help
3447	  Controls how `build_error!` and `build_assert!` are handled during the build.
3448
3449	  If calls to them exist in the binary, it may indicate a violated invariant
3450	  or that the optimizer failed to verify the invariant during compilation.
3451
3452	  This should not happen, thus by default the build is aborted. However,
3453	  as an escape hatch, you can choose Y here to ignore them during build
3454	  and let the check be carried at runtime (with `panic!` being called if
3455	  the check fails).
3456
3457	  If unsure, say N.
3458
3459config RUST_KERNEL_DOCTESTS
3460	bool "Doctests for the `kernel` crate" if !KUNIT_ALL_TESTS
3461	depends on RUST && KUNIT=y
3462	default KUNIT_ALL_TESTS
3463	help
3464	  This builds the documentation tests of the `kernel` crate
3465	  as KUnit tests.
3466
3467	  For more information on KUnit and unit tests in general,
3468	  please refer to the KUnit documentation in Documentation/dev-tools/kunit/.
3469
3470	  If unsure, say N.
3471
3472endmenu # "Rust"
3473
3474endmenu # Kernel hacking
3475