xref: /linux-6.15/lib/Kconfig.debug (revision 3f1724dd)
1# SPDX-License-Identifier: GPL-2.0-only
2menu "Kernel hacking"
3
4menu "printk and dmesg options"
5
6config PRINTK_TIME
7	bool "Show timing information on printks"
8	depends on PRINTK
9	help
10	  Selecting this option causes time stamps of the printk()
11	  messages to be added to the output of the syslog() system
12	  call and at the console.
13
14	  The timestamp is always recorded internally, and exported
15	  to /dev/kmsg. This flag just specifies if the timestamp should
16	  be included, not that the timestamp is recorded.
17
18	  The behavior is also controlled by the kernel command line
19	  parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
20
21config PRINTK_CALLER
22	bool "Show caller information on printks"
23	depends on PRINTK
24	help
25	  Selecting this option causes printk() to add a caller "thread id" (if
26	  in task context) or a caller "processor id" (if not in task context)
27	  to every message.
28
29	  This option is intended for environments where multiple threads
30	  concurrently call printk() for many times, for it is difficult to
31	  interpret without knowing where these lines (or sometimes individual
32	  line which was divided into multiple lines due to race) came from.
33
34	  Since toggling after boot makes the code racy, currently there is
35	  no option to enable/disable at the kernel command line parameter or
36	  sysfs interface.
37
38config STACKTRACE_BUILD_ID
39	bool "Show build ID information in stacktraces"
40	depends on PRINTK
41	help
42	  Selecting this option adds build ID information for symbols in
43	  stacktraces printed with the printk format '%p[SR]b'.
44
45	  This option is intended for distros where debuginfo is not easily
46	  accessible but can be downloaded given the build ID of the vmlinux or
47	  kernel module where the function is located.
48
49config CONSOLE_LOGLEVEL_DEFAULT
50	int "Default console loglevel (1-15)"
51	range 1 15
52	default "7"
53	help
54	  Default loglevel to determine what will be printed on the console.
55
56	  Setting a default here is equivalent to passing in loglevel=<x> in
57	  the kernel bootargs. loglevel=<x> continues to override whatever
58	  value is specified here as well.
59
60	  Note: This does not affect the log level of un-prefixed printk()
61	  usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
62	  option.
63
64config CONSOLE_LOGLEVEL_QUIET
65	int "quiet console loglevel (1-15)"
66	range 1 15
67	default "4"
68	help
69	  loglevel to use when "quiet" is passed on the kernel commandline.
70
71	  When "quiet" is passed on the kernel commandline this loglevel
72	  will be used as the loglevel. IOW passing "quiet" will be the
73	  equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
74
75config MESSAGE_LOGLEVEL_DEFAULT
76	int "Default message log level (1-7)"
77	range 1 7
78	default "4"
79	help
80	  Default log level for printk statements with no specified priority.
81
82	  This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
83	  that are auditing their logs closely may want to set it to a lower
84	  priority.
85
86	  Note: This does not affect what message level gets printed on the console
87	  by default. To change that, use loglevel=<x> in the kernel bootargs,
88	  or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
89
90config BOOT_PRINTK_DELAY
91	bool "Delay each boot printk message by N milliseconds"
92	depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
93	help
94	  This build option allows you to read kernel boot messages
95	  by inserting a short delay after each one.  The delay is
96	  specified in milliseconds on the kernel command line,
97	  using "boot_delay=N".
98
99	  It is likely that you would also need to use "lpj=M" to preset
100	  the "loops per jiffy" value.
101	  See a previous boot log for the "lpj" value to use for your
102	  system, and then set "lpj=M" before setting "boot_delay=N".
103	  NOTE:  Using this option may adversely affect SMP systems.
104	  I.e., processors other than the first one may not boot up.
105	  BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
106	  what it believes to be lockup conditions.
107
108config DYNAMIC_DEBUG
109	bool "Enable dynamic printk() support"
110	default n
111	depends on PRINTK
112	depends on (DEBUG_FS || PROC_FS)
113	select DYNAMIC_DEBUG_CORE
114	help
115
116	  Compiles debug level messages into the kernel, which would not
117	  otherwise be available at runtime. These messages can then be
118	  enabled/disabled based on various levels of scope - per source file,
119	  function, module, format string, and line number. This mechanism
120	  implicitly compiles in all pr_debug() and dev_dbg() calls, which
121	  enlarges the kernel text size by about 2%.
122
123	  If a source file is compiled with DEBUG flag set, any
124	  pr_debug() calls in it are enabled by default, but can be
125	  disabled at runtime as below.  Note that DEBUG flag is
126	  turned on by many CONFIG_*DEBUG* options.
127
128	  Usage:
129
130	  Dynamic debugging is controlled via the 'dynamic_debug/control' file,
131	  which is contained in the 'debugfs' filesystem or procfs.
132	  Thus, the debugfs or procfs filesystem must first be mounted before
133	  making use of this feature.
134	  We refer the control file as: <debugfs>/dynamic_debug/control. This
135	  file contains a list of the debug statements that can be enabled. The
136	  format for each line of the file is:
137
138		filename:lineno [module]function flags format
139
140	  filename : source file of the debug statement
141	  lineno : line number of the debug statement
142	  module : module that contains the debug statement
143	  function : function that contains the debug statement
144	  flags : '=p' means the line is turned 'on' for printing
145	  format : the format used for the debug statement
146
147	  From a live system:
148
149		nullarbor:~ # cat <debugfs>/dynamic_debug/control
150		# filename:lineno [module]function flags format
151		fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
152		fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
153		fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
154
155	  Example usage:
156
157		// enable the message at line 1603 of file svcsock.c
158		nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
159						<debugfs>/dynamic_debug/control
160
161		// enable all the messages in file svcsock.c
162		nullarbor:~ # echo -n 'file svcsock.c +p' >
163						<debugfs>/dynamic_debug/control
164
165		// enable all the messages in the NFS server module
166		nullarbor:~ # echo -n 'module nfsd +p' >
167						<debugfs>/dynamic_debug/control
168
169		// enable all 12 messages in the function svc_process()
170		nullarbor:~ # echo -n 'func svc_process +p' >
171						<debugfs>/dynamic_debug/control
172
173		// disable all 12 messages in the function svc_process()
174		nullarbor:~ # echo -n 'func svc_process -p' >
175						<debugfs>/dynamic_debug/control
176
177	  See Documentation/admin-guide/dynamic-debug-howto.rst for additional
178	  information.
179
180config DYNAMIC_DEBUG_CORE
181	bool "Enable core function of dynamic debug support"
182	depends on PRINTK
183	depends on (DEBUG_FS || PROC_FS)
184	help
185	  Enable core functional support of dynamic debug. It is useful
186	  when you want to tie dynamic debug to your kernel modules with
187	  DYNAMIC_DEBUG_MODULE defined for each of them, especially for
188	  the case of embedded system where the kernel image size is
189	  sensitive for people.
190
191config SYMBOLIC_ERRNAME
192	bool "Support symbolic error names in printf"
193	default y if PRINTK
194	help
195	  If you say Y here, the kernel's printf implementation will
196	  be able to print symbolic error names such as ENOSPC instead
197	  of the number 28. It makes the kernel image slightly larger
198	  (about 3KB), but can make the kernel logs easier to read.
199
200config DEBUG_BUGVERBOSE
201	bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
202	depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
203	default y
204	help
205	  Say Y here to make BUG() panics output the file name and line number
206	  of the BUG call as well as the EIP and oops trace.  This aids
207	  debugging but costs about 70-100K of memory.
208
209endmenu # "printk and dmesg options"
210
211config DEBUG_KERNEL
212	bool "Kernel debugging"
213	help
214	  Say Y here if you are developing drivers or trying to debug and
215	  identify kernel problems.
216
217config DEBUG_MISC
218	bool "Miscellaneous debug code"
219	default DEBUG_KERNEL
220	depends on DEBUG_KERNEL
221	help
222	  Say Y here if you need to enable miscellaneous debug code that should
223	  be under a more specific debug option but isn't.
224
225menu "Compile-time checks and compiler options"
226
227config DEBUG_INFO
228	bool
229	help
230	  A kernel debug info option other than "None" has been selected
231	  in the "Debug information" choice below, indicating that debug
232	  information will be generated for build targets.
233
234# Clang generates .uleb128 with label differences for DWARF v5, a feature that
235# older binutils ports do not support when utilizing RISC-V style linker
236# relaxation: https://sourceware.org/bugzilla/show_bug.cgi?id=27215
237config AS_HAS_NON_CONST_ULEB128
238	def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:)
239
240choice
241	prompt "Debug information"
242	depends on DEBUG_KERNEL
243	help
244	  Selecting something other than "None" results in a kernel image
245	  that will include debugging info resulting in a larger kernel image.
246	  This adds debug symbols to the kernel and modules (gcc -g), and
247	  is needed if you intend to use kernel crashdump or binary object
248	  tools like crash, kgdb, LKCD, gdb, etc on the kernel.
249
250	  Choose which version of DWARF debug info to emit. If unsure,
251	  select "Toolchain default".
252
253config DEBUG_INFO_NONE
254	bool "Disable debug information"
255	help
256	  Do not build the kernel with debugging information, which will
257	  result in a faster and smaller build.
258
259config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
260	bool "Rely on the toolchain's implicit default DWARF version"
261	select DEBUG_INFO
262	depends on !CC_IS_CLANG || AS_IS_LLVM || CLANG_VERSION < 140000 || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128)
263	help
264	  The implicit default version of DWARF debug info produced by a
265	  toolchain changes over time.
266
267	  This can break consumers of the debug info that haven't upgraded to
268	  support newer revisions, and prevent testing newer versions, but
269	  those should be less common scenarios.
270
271config DEBUG_INFO_DWARF4
272	bool "Generate DWARF Version 4 debuginfo"
273	select DEBUG_INFO
274	depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)
275	help
276	  Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2
277	  if using clang without clang's integrated assembler, and gdb 7.0+.
278
279	  If you have consumers of DWARF debug info that are not ready for
280	  newer revisions of DWARF, you may wish to choose this or have your
281	  config select this.
282
283config DEBUG_INFO_DWARF5
284	bool "Generate DWARF Version 5 debuginfo"
285	select DEBUG_INFO
286	depends on !ARCH_HAS_BROKEN_DWARF5
287	depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128)
288	help
289	  Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
290	  5.0+ accepts the -gdwarf-5 flag but only had partial support for some
291	  draft features until 7.0), and gdb 8.0+.
292
293	  Changes to the structure of debug info in Version 5 allow for around
294	  15-18% savings in resulting image and debug info section sizes as
295	  compared to DWARF Version 4. DWARF Version 5 standardizes previous
296	  extensions such as accelerators for symbol indexing and the format
297	  for fission (.dwo/.dwp) files. Users may not want to select this
298	  config if they rely on tooling that has not yet been updated to
299	  support DWARF Version 5.
300
301endchoice # "Debug information"
302
303if DEBUG_INFO
304
305config DEBUG_INFO_REDUCED
306	bool "Reduce debugging information"
307	help
308	  If you say Y here gcc is instructed to generate less debugging
309	  information for structure types. This means that tools that
310	  need full debugging information (like kgdb or systemtap) won't
311	  be happy. But if you merely need debugging information to
312	  resolve line numbers there is no loss. Advantage is that
313	  build directory object sizes shrink dramatically over a full
314	  DEBUG_INFO build and compile times are reduced too.
315	  Only works with newer gcc versions.
316
317choice
318	prompt "Compressed Debug information"
319	help
320	  Compress the resulting debug info. Results in smaller debug info sections,
321	  but requires that consumers are able to decompress the results.
322
323	  If unsure, choose DEBUG_INFO_COMPRESSED_NONE.
324
325config DEBUG_INFO_COMPRESSED_NONE
326	bool "Don't compress debug information"
327	help
328	  Don't compress debug info sections.
329
330config DEBUG_INFO_COMPRESSED_ZLIB
331	bool "Compress debugging information with zlib"
332	depends on $(cc-option,-gz=zlib)
333	depends on $(ld-option,--compress-debug-sections=zlib)
334	help
335	  Compress the debug information using zlib.  Requires GCC 5.0+ or Clang
336	  5.0+, binutils 2.26+, and zlib.
337
338	  Users of dpkg-deb via scripts/package/builddeb may find an increase in
339	  size of their debug .deb packages with this config set, due to the
340	  debug info being compressed with zlib, then the object files being
341	  recompressed with a different compression scheme. But this is still
342	  preferable to setting $KDEB_COMPRESS to "none" which would be even
343	  larger.
344
345config DEBUG_INFO_COMPRESSED_ZSTD
346	bool "Compress debugging information with zstd"
347	depends on $(cc-option,-gz=zstd)
348	depends on $(ld-option,--compress-debug-sections=zstd)
349	help
350	  Compress the debug information using zstd.  This may provide better
351	  compression than zlib, for about the same time costs, but requires newer
352	  toolchain support.  Requires GCC 13.0+ or Clang 16.0+, binutils 2.40+, and
353	  zstd.
354
355endchoice # "Compressed Debug information"
356
357config DEBUG_INFO_SPLIT
358	bool "Produce split debuginfo in .dwo files"
359	depends on $(cc-option,-gsplit-dwarf)
360	# RISC-V linker relaxation + -gsplit-dwarf has issues with LLVM and GCC
361	# prior to 12.x:
362	# https://github.com/llvm/llvm-project/issues/56642
363	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99090
364	depends on !RISCV || GCC_VERSION >= 120000
365	help
366	  Generate debug info into separate .dwo files. This significantly
367	  reduces the build directory size for builds with DEBUG_INFO,
368	  because it stores the information only once on disk in .dwo
369	  files instead of multiple times in object files and executables.
370	  In addition the debug information is also compressed.
371
372	  Requires recent gcc (4.7+) and recent gdb/binutils.
373	  Any tool that packages or reads debug information would need
374	  to know about the .dwo files and include them.
375	  Incompatible with older versions of ccache.
376
377config DEBUG_INFO_BTF
378	bool "Generate BTF type information"
379	depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
380	depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
381	depends on BPF_SYSCALL
382	depends on PAHOLE_VERSION >= 116
383	depends on DEBUG_INFO_DWARF4 || PAHOLE_VERSION >= 121
384	# pahole uses elfutils, which does not have support for Hexagon relocations
385	depends on !HEXAGON
386	help
387	  Generate deduplicated BTF type information from DWARF debug info.
388	  Turning this on requires pahole v1.16 or later (v1.21 or later to
389	  support DWARF 5), which will convert DWARF type info into equivalent
390	  deduplicated BTF type info.
391
392config PAHOLE_HAS_SPLIT_BTF
393	def_bool PAHOLE_VERSION >= 119
394
395config PAHOLE_HAS_BTF_TAG
396	def_bool PAHOLE_VERSION >= 123
397	depends on CC_IS_CLANG
398	help
399	  Decide whether pahole emits btf_tag attributes (btf_type_tag and
400	  btf_decl_tag) or not. Currently only clang compiler implements
401	  these attributes, so make the config depend on CC_IS_CLANG.
402
403config PAHOLE_HAS_LANG_EXCLUDE
404	def_bool PAHOLE_VERSION >= 124
405	help
406	  Support for the --lang_exclude flag which makes pahole exclude
407	  compilation units from the supplied language. Used in Kbuild to
408	  omit Rust CUs which are not supported in version 1.24 of pahole,
409	  otherwise it would emit malformed kernel and module binaries when
410	  using DEBUG_INFO_BTF_MODULES.
411
412config DEBUG_INFO_BTF_MODULES
413	bool "Generate BTF type information for kernel modules"
414	default y
415	depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
416	help
417	  Generate compact split BTF type information for kernel modules.
418
419config MODULE_ALLOW_BTF_MISMATCH
420	bool "Allow loading modules with non-matching BTF type info"
421	depends on DEBUG_INFO_BTF_MODULES
422	help
423	  For modules whose split BTF does not match vmlinux, load without
424	  BTF rather than refusing to load. The default behavior with
425	  module BTF enabled is to reject modules with such mismatches;
426	  this option will still load module BTF where possible but ignore
427	  it when a mismatch is found.
428
429config GDB_SCRIPTS
430	bool "Provide GDB scripts for kernel debugging"
431	help
432	  This creates the required links to GDB helper scripts in the
433	  build directory. If you load vmlinux into gdb, the helper
434	  scripts will be automatically imported by gdb as well, and
435	  additional functions are available to analyze a Linux kernel
436	  instance. See Documentation/process/debugging/gdb-kernel-debugging.rst
437	  for further details.
438
439endif # DEBUG_INFO
440
441config FRAME_WARN
442	int "Warn for stack frames larger than"
443	range 0 8192
444	default 0 if KMSAN
445	default 2048 if GCC_PLUGIN_LATENT_ENTROPY
446	default 2048 if PARISC
447	default 1536 if (!64BIT && XTENSA)
448	default 1280 if KASAN && !64BIT
449	default 1024 if !64BIT
450	default 2048 if 64BIT
451	help
452	  Tell the compiler to warn at build time for stack frames larger than this.
453	  Setting this too low will cause a lot of warnings.
454	  Setting it to 0 disables the warning.
455
456config STRIP_ASM_SYMS
457	bool "Strip assembler-generated symbols during link"
458	default n
459	help
460	  Strip internal assembler-generated symbols during a link (symbols
461	  that look like '.Lxxx') so they don't pollute the output of
462	  get_wchan() and suchlike.
463
464config READABLE_ASM
465	bool "Generate readable assembler code"
466	depends on DEBUG_KERNEL
467	depends on CC_IS_GCC
468	help
469	  Disable some compiler optimizations that tend to generate human unreadable
470	  assembler output. This may make the kernel slightly slower, but it helps
471	  to keep kernel developers who have to stare a lot at assembler listings
472	  sane.
473
474config HEADERS_INSTALL
475	bool "Install uapi headers to usr/include"
476	depends on !UML
477	help
478	  This option will install uapi headers (headers exported to user-space)
479	  into the usr/include directory for use during the kernel build.
480	  This is unneeded for building the kernel itself, but needed for some
481	  user-space program samples. It is also needed by some features such
482	  as uapi header sanity checks.
483
484config DEBUG_SECTION_MISMATCH
485	bool "Enable full Section mismatch analysis"
486	depends on CC_IS_GCC
487	help
488	  The section mismatch analysis checks if there are illegal
489	  references from one section to another section.
490	  During linktime or runtime, some sections are dropped;
491	  any use of code/data previously in these sections would
492	  most likely result in an oops.
493	  In the code, functions and variables are annotated with
494	  __init,, etc. (see the full list in include/linux/init.h),
495	  which results in the code/data being placed in specific sections.
496	  The section mismatch analysis is always performed after a full
497	  kernel build, and enabling this option causes the following
498	  additional step to occur:
499	  - Add the option -fno-inline-functions-called-once to gcc commands.
500	    When inlining a function annotated with __init in a non-init
501	    function, we would lose the section information and thus
502	    the analysis would not catch the illegal reference.
503	    This option tells gcc to inline less (but it does result in
504	    a larger kernel).
505
506config SECTION_MISMATCH_WARN_ONLY
507	bool "Make section mismatch errors non-fatal"
508	default y
509	help
510	  If you say N here, the build process will fail if there are any
511	  section mismatch, instead of just throwing warnings.
512
513	  If unsure, say Y.
514
515config DEBUG_FORCE_FUNCTION_ALIGN_64B
516	bool "Force all function address 64B aligned"
517	depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC || RISCV || S390)
518	select FUNCTION_ALIGNMENT_64B
519	help
520	  There are cases that a commit from one domain changes the function
521	  address alignment of other domains, and cause magic performance
522	  bump (regression or improvement). Enable this option will help to
523	  verify if the bump is caused by function alignment changes, while
524	  it will slightly increase the kernel size and affect icache usage.
525
526	  It is mainly for debug and performance tuning use.
527
528#
529# Select this config option from the architecture Kconfig, if it
530# is preferred to always offer frame pointers as a config
531# option on the architecture (regardless of KERNEL_DEBUG):
532#
533config ARCH_WANT_FRAME_POINTERS
534	bool
535
536config FRAME_POINTER
537	bool "Compile the kernel with frame pointers"
538	depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
539	default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
540	help
541	  If you say Y here the resulting kernel image will be slightly
542	  larger and slower, but it gives very useful debugging information
543	  in case of kernel bugs. (precise oopses/stacktraces/warnings)
544
545config OBJTOOL
546	bool
547
548config STACK_VALIDATION
549	bool "Compile-time stack metadata validation"
550	depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
551	select OBJTOOL
552	default n
553	help
554	  Validate frame pointer rules at compile-time.  This helps ensure that
555	  runtime stack traces are more reliable.
556
557	  For more information, see
558	  tools/objtool/Documentation/objtool.txt.
559
560config NOINSTR_VALIDATION
561	bool
562	depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
563	select OBJTOOL
564	default y
565
566config VMLINUX_MAP
567	bool "Generate vmlinux.map file when linking"
568	depends on EXPERT
569	help
570	  Selecting this option will pass "-Map=vmlinux.map" to ld
571	  when linking vmlinux. That file can be useful for verifying
572	  and debugging magic section games, and for seeing which
573	  pieces of code get eliminated with
574	  CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
575
576config BUILTIN_MODULE_RANGES
577	bool "Generate address range information for builtin modules"
578	depends on !LTO
579	depends on VMLINUX_MAP
580	help
581	 When modules are built into the kernel, there will be no module name
582	 associated with its symbols in /proc/kallsyms.  Tracers may want to
583	 identify symbols by module name and symbol name regardless of whether
584	 the module is configured as loadable or not.
585
586	 This option generates modules.builtin.ranges in the build tree with
587	 offset ranges (per ELF section) for the module(s) they belong to.
588	 It also records an anchor symbol to determine the load address of the
589	 section.
590
591config DEBUG_FORCE_WEAK_PER_CPU
592	bool "Force weak per-cpu definitions"
593	depends on DEBUG_KERNEL
594	help
595	  s390 and alpha require percpu variables in modules to be
596	  defined weak to work around addressing range issue which
597	  puts the following two restrictions on percpu variable
598	  definitions.
599
600	  1. percpu symbols must be unique whether static or not
601	  2. percpu variables can't be defined inside a function
602
603	  To ensure that generic code follows the above rules, this
604	  option forces all percpu variables to be defined as weak.
605
606endmenu # "Compiler options"
607
608menu "Generic Kernel Debugging Instruments"
609
610config MAGIC_SYSRQ
611	bool "Magic SysRq key"
612	depends on !UML
613	help
614	  If you say Y here, you will have some control over the system even
615	  if the system crashes for example during kernel debugging (e.g., you
616	  will be able to flush the buffer cache to disk, reboot the system
617	  immediately or dump some status information). This is accomplished
618	  by pressing various keys while holding SysRq (Alt+PrintScreen). It
619	  also works on a serial console (on PC hardware at least), if you
620	  send a BREAK and then within 5 seconds a command keypress. The
621	  keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
622	  Don't say Y unless you really know what this hack does.
623
624config MAGIC_SYSRQ_DEFAULT_ENABLE
625	hex "Enable magic SysRq key functions by default"
626	depends on MAGIC_SYSRQ
627	default 0x1
628	help
629	  Specifies which SysRq key functions are enabled by default.
630	  This may be set to 1 or 0 to enable or disable them all, or
631	  to a bitmask as described in Documentation/admin-guide/sysrq.rst.
632
633config MAGIC_SYSRQ_SERIAL
634	bool "Enable magic SysRq key over serial"
635	depends on MAGIC_SYSRQ
636	default y
637	help
638	  Many embedded boards have a disconnected TTL level serial which can
639	  generate some garbage that can lead to spurious false sysrq detects.
640	  This option allows you to decide whether you want to enable the
641	  magic SysRq key.
642
643config MAGIC_SYSRQ_SERIAL_SEQUENCE
644	string "Char sequence that enables magic SysRq over serial"
645	depends on MAGIC_SYSRQ_SERIAL
646	default ""
647	help
648	  Specifies a sequence of characters that can follow BREAK to enable
649	  SysRq on a serial console.
650
651	  If unsure, leave an empty string and the option will not be enabled.
652
653config DEBUG_FS
654	bool "Debug Filesystem"
655	help
656	  debugfs is a virtual file system that kernel developers use to put
657	  debugging files into.  Enable this option to be able to read and
658	  write to these files.
659
660	  For detailed documentation on the debugfs API, see
661	  Documentation/filesystems/.
662
663	  If unsure, say N.
664
665choice
666	prompt "Debugfs default access"
667	depends on DEBUG_FS
668	default DEBUG_FS_ALLOW_ALL
669	help
670	  This selects the default access restrictions for debugfs.
671	  It can be overridden with kernel command line option
672	  debugfs=[on,no-mount,off]. The restrictions apply for API access
673	  and filesystem registration.
674
675config DEBUG_FS_ALLOW_ALL
676	bool "Access normal"
677	help
678	  No restrictions apply. Both API and filesystem registration
679	  is on. This is the normal default operation.
680
681config DEBUG_FS_DISALLOW_MOUNT
682	bool "Do not register debugfs as filesystem"
683	help
684	  The API is open but filesystem is not loaded. Clients can still do
685	  their work and read with debug tools that do not need
686	  debugfs filesystem.
687
688config DEBUG_FS_ALLOW_NONE
689	bool "No access"
690	help
691	  Access is off. Clients get -PERM when trying to create nodes in
692	  debugfs tree and debugfs is not registered as a filesystem.
693	  Client can then back-off or continue without debugfs access.
694
695endchoice
696
697source "lib/Kconfig.kgdb"
698source "lib/Kconfig.ubsan"
699source "lib/Kconfig.kcsan"
700
701endmenu
702
703menu "Networking Debugging"
704
705source "net/Kconfig.debug"
706
707endmenu # "Networking Debugging"
708
709menu "Memory Debugging"
710
711source "mm/Kconfig.debug"
712
713config DEBUG_OBJECTS
714	bool "Debug object operations"
715	depends on DEBUG_KERNEL
716	help
717	  If you say Y here, additional code will be inserted into the
718	  kernel to track the life time of various objects and validate
719	  the operations on those objects.
720
721config DEBUG_OBJECTS_SELFTEST
722	bool "Debug objects selftest"
723	depends on DEBUG_OBJECTS
724	help
725	  This enables the selftest of the object debug code.
726
727config DEBUG_OBJECTS_FREE
728	bool "Debug objects in freed memory"
729	depends on DEBUG_OBJECTS
730	help
731	  This enables checks whether a k/v free operation frees an area
732	  which contains an object which has not been deactivated
733	  properly. This can make kmalloc/kfree-intensive workloads
734	  much slower.
735
736config DEBUG_OBJECTS_TIMERS
737	bool "Debug timer objects"
738	depends on DEBUG_OBJECTS
739	help
740	  If you say Y here, additional code will be inserted into the
741	  timer routines to track the life time of timer objects and
742	  validate the timer operations.
743
744config DEBUG_OBJECTS_WORK
745	bool "Debug work objects"
746	depends on DEBUG_OBJECTS
747	help
748	  If you say Y here, additional code will be inserted into the
749	  work queue routines to track the life time of work objects and
750	  validate the work operations.
751
752config DEBUG_OBJECTS_RCU_HEAD
753	bool "Debug RCU callbacks objects"
754	depends on DEBUG_OBJECTS
755	help
756	  Enable this to turn on debugging of RCU list heads (call_rcu() usage).
757
758config DEBUG_OBJECTS_PERCPU_COUNTER
759	bool "Debug percpu counter objects"
760	depends on DEBUG_OBJECTS
761	help
762	  If you say Y here, additional code will be inserted into the
763	  percpu counter routines to track the life time of percpu counter
764	  objects and validate the percpu counter operations.
765
766config DEBUG_OBJECTS_ENABLE_DEFAULT
767	int "debug_objects bootup default value (0-1)"
768	range 0 1
769	default "1"
770	depends on DEBUG_OBJECTS
771	help
772	  Debug objects boot parameter default value
773
774config SHRINKER_DEBUG
775	bool "Enable shrinker debugging support"
776	depends on DEBUG_FS
777	help
778	  Say Y to enable the shrinker debugfs interface which provides
779	  visibility into the kernel memory shrinkers subsystem.
780	  Disable it to avoid an extra memory footprint.
781
782config DEBUG_STACK_USAGE
783	bool "Stack utilization instrumentation"
784	depends on DEBUG_KERNEL
785	help
786	  Enables the display of the minimum amount of free stack which each
787	  task has ever had available in the sysrq-T and sysrq-P debug output.
788	  Also emits a message to dmesg when a process exits if that process
789	  used more stack space than previously exiting processes.
790
791	  This option will slow down process creation somewhat.
792
793config SCHED_STACK_END_CHECK
794	bool "Detect stack corruption on calls to schedule()"
795	depends on DEBUG_KERNEL
796	default n
797	help
798	  This option checks for a stack overrun on calls to schedule().
799	  If the stack end location is found to be over written always panic as
800	  the content of the corrupted region can no longer be trusted.
801	  This is to ensure no erroneous behaviour occurs which could result in
802	  data corruption or a sporadic crash at a later stage once the region
803	  is examined. The runtime overhead introduced is minimal.
804
805config ARCH_HAS_DEBUG_VM_PGTABLE
806	bool
807	help
808	  An architecture should select this when it can successfully
809	  build and run DEBUG_VM_PGTABLE.
810
811config DEBUG_VFS
812	bool "Debug VFS"
813	depends on DEBUG_KERNEL
814	help
815	  Enable this to turn on extended checks in the VFS layer that may impact
816	  performance.
817
818	  If unsure, say N.
819
820config DEBUG_VM_IRQSOFF
821	def_bool DEBUG_VM && !PREEMPT_RT
822
823config DEBUG_VM
824	bool "Debug VM"
825	depends on DEBUG_KERNEL
826	help
827	  Enable this to turn on extended checks in the virtual-memory system
828	  that may impact performance.
829
830	  If unsure, say N.
831
832config DEBUG_VM_SHOOT_LAZIES
833	bool "Debug MMU_LAZY_TLB_SHOOTDOWN implementation"
834	depends on DEBUG_VM
835	depends on MMU_LAZY_TLB_SHOOTDOWN
836	help
837	  Enable additional IPIs that ensure lazy tlb mm references are removed
838	  before the mm is freed.
839
840	  If unsure, say N.
841
842config DEBUG_VM_MAPLE_TREE
843	bool "Debug VM maple trees"
844	depends on DEBUG_VM
845	select DEBUG_MAPLE_TREE
846	help
847	  Enable VM maple tree debugging information and extra validations.
848
849	  If unsure, say N.
850
851config DEBUG_VM_RB
852	bool "Debug VM red-black trees"
853	depends on DEBUG_VM
854	help
855	  Enable VM red-black tree debugging information and extra validations.
856
857	  If unsure, say N.
858
859config DEBUG_VM_PGFLAGS
860	bool "Debug page-flags operations"
861	depends on DEBUG_VM
862	help
863	  Enables extra validation on page flags operations.
864
865	  If unsure, say N.
866
867config DEBUG_VM_PGTABLE
868	bool "Debug arch page table for semantics compliance"
869	depends on MMU
870	depends on ARCH_HAS_DEBUG_VM_PGTABLE
871	default y if DEBUG_VM
872	help
873	  This option provides a debug method which can be used to test
874	  architecture page table helper functions on various platforms in
875	  verifying if they comply with expected generic MM semantics. This
876	  will help architecture code in making sure that any changes or
877	  new additions of these helpers still conform to expected
878	  semantics of the generic MM. Platforms will have to opt in for
879	  this through ARCH_HAS_DEBUG_VM_PGTABLE.
880
881	  If unsure, say N.
882
883config ARCH_HAS_DEBUG_VIRTUAL
884	bool
885
886config DEBUG_VIRTUAL
887	bool "Debug VM translations"
888	depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
889	help
890	  Enable some costly sanity checks in virtual to page code. This can
891	  catch mistakes with virt_to_page() and friends.
892
893	  If unsure, say N.
894
895config DEBUG_NOMMU_REGIONS
896	bool "Debug the global anon/private NOMMU mapping region tree"
897	depends on DEBUG_KERNEL && !MMU
898	help
899	  This option causes the global tree of anonymous and private mapping
900	  regions to be regularly checked for invalid topology.
901
902config DEBUG_MEMORY_INIT
903	bool "Debug memory initialisation" if EXPERT
904	default !EXPERT
905	help
906	  Enable this for additional checks during memory initialisation.
907	  The sanity checks verify aspects of the VM such as the memory model
908	  and other information provided by the architecture. Verbose
909	  information will be printed at KERN_DEBUG loglevel depending
910	  on the mminit_loglevel= command-line option.
911
912	  If unsure, say Y
913
914config MEMORY_NOTIFIER_ERROR_INJECT
915	tristate "Memory hotplug notifier error injection module"
916	depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
917	help
918	  This option provides the ability to inject artificial errors to
919	  memory hotplug notifier chain callbacks.  It is controlled through
920	  debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
921
922	  If the notifier call chain should be failed with some events
923	  notified, write the error code to "actions/<notifier event>/error".
924
925	  Example: Inject memory hotplug offline error (-12 == -ENOMEM)
926
927	  # cd /sys/kernel/debug/notifier-error-inject/memory
928	  # echo -12 > actions/MEM_GOING_OFFLINE/error
929	  # echo offline > /sys/devices/system/memory/memoryXXX/state
930	  bash: echo: write error: Cannot allocate memory
931
932	  To compile this code as a module, choose M here: the module will
933	  be called memory-notifier-error-inject.
934
935	  If unsure, say N.
936
937config DEBUG_PER_CPU_MAPS
938	bool "Debug access to per_cpu maps"
939	depends on DEBUG_KERNEL
940	depends on SMP
941	help
942	  Say Y to verify that the per_cpu map being accessed has
943	  been set up. This adds a fair amount of code to kernel memory
944	  and decreases performance.
945
946	  Say N if unsure.
947
948config DEBUG_KMAP_LOCAL
949	bool "Debug kmap_local temporary mappings"
950	depends on DEBUG_KERNEL && KMAP_LOCAL
951	help
952	  This option enables additional error checking for the kmap_local
953	  infrastructure.  Disable for production use.
954
955config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
956	bool
957
958config DEBUG_KMAP_LOCAL_FORCE_MAP
959	bool "Enforce kmap_local temporary mappings"
960	depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
961	select KMAP_LOCAL
962	select DEBUG_KMAP_LOCAL
963	help
964	  This option enforces temporary mappings through the kmap_local
965	  mechanism for non-highmem pages and on non-highmem systems.
966	  Disable this for production systems!
967
968config DEBUG_HIGHMEM
969	bool "Highmem debugging"
970	depends on DEBUG_KERNEL && HIGHMEM
971	select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
972	select DEBUG_KMAP_LOCAL
973	help
974	  This option enables additional error checking for high memory
975	  systems.  Disable for production systems.
976
977config HAVE_DEBUG_STACKOVERFLOW
978	bool
979
980config DEBUG_STACKOVERFLOW
981	bool "Check for stack overflows"
982	depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
983	help
984	  Say Y here if you want to check for overflows of kernel, IRQ
985	  and exception stacks (if your architecture uses them). This
986	  option will show detailed messages if free stack space drops
987	  below a certain limit.
988
989	  These kinds of bugs usually occur when call-chains in the
990	  kernel get too deep, especially when interrupts are
991	  involved.
992
993	  Use this in cases where you see apparently random memory
994	  corruption, especially if it appears in 'struct thread_info'
995
996	  If in doubt, say "N".
997
998config CODE_TAGGING
999	bool
1000	select KALLSYMS
1001
1002config MEM_ALLOC_PROFILING
1003	bool "Enable memory allocation profiling"
1004	default n
1005	depends on MMU
1006	depends on PROC_FS
1007	depends on !DEBUG_FORCE_WEAK_PER_CPU
1008	select CODE_TAGGING
1009	select PAGE_EXTENSION
1010	select SLAB_OBJ_EXT
1011	help
1012	  Track allocation source code and record total allocation size
1013	  initiated at that code location. The mechanism can be used to track
1014	  memory leaks with a low performance and memory impact.
1015
1016config MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
1017	bool "Enable memory allocation profiling by default"
1018	default y
1019	depends on MEM_ALLOC_PROFILING
1020
1021config MEM_ALLOC_PROFILING_DEBUG
1022	bool "Memory allocation profiler debugging"
1023	default n
1024	depends on MEM_ALLOC_PROFILING
1025	select MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
1026	help
1027	  Adds warnings with helpful error messages for memory allocation
1028	  profiling.
1029
1030source "lib/Kconfig.kasan"
1031source "lib/Kconfig.kfence"
1032source "lib/Kconfig.kmsan"
1033
1034endmenu # "Memory Debugging"
1035
1036config DEBUG_SHIRQ
1037	bool "Debug shared IRQ handlers"
1038	depends on DEBUG_KERNEL
1039	help
1040	  Enable this to generate a spurious interrupt just before a shared
1041	  interrupt handler is deregistered (generating one when registering
1042	  is currently disabled). Drivers need to handle this correctly. Some
1043	  don't and need to be caught.
1044
1045menu "Debug Oops, Lockups and Hangs"
1046
1047config PANIC_ON_OOPS
1048	bool "Panic on Oops"
1049	help
1050	  Say Y here to enable the kernel to panic when it oopses. This
1051	  has the same effect as setting oops=panic on the kernel command
1052	  line.
1053
1054	  This feature is useful to ensure that the kernel does not do
1055	  anything erroneous after an oops which could result in data
1056	  corruption or other issues.
1057
1058	  Say N if unsure.
1059
1060config PANIC_ON_OOPS_VALUE
1061	int
1062	range 0 1
1063	default 0 if !PANIC_ON_OOPS
1064	default 1 if PANIC_ON_OOPS
1065
1066config PANIC_TIMEOUT
1067	int "panic timeout"
1068	default 0
1069	help
1070	  Set the timeout value (in seconds) until a reboot occurs when
1071	  the kernel panics. If n = 0, then we wait forever. A timeout
1072	  value n > 0 will wait n seconds before rebooting, while a timeout
1073	  value n < 0 will reboot immediately. This setting can be overridden
1074	  with the kernel command line option panic=, and from userspace via
1075	  /proc/sys/kernel/panic.
1076
1077config LOCKUP_DETECTOR
1078	bool
1079
1080config SOFTLOCKUP_DETECTOR
1081	bool "Detect Soft Lockups"
1082	depends on DEBUG_KERNEL && !S390
1083	select LOCKUP_DETECTOR
1084	help
1085	  Say Y here to enable the kernel to act as a watchdog to detect
1086	  soft lockups.
1087
1088	  Softlockups are bugs that cause the kernel to loop in kernel
1089	  mode for more than 20 seconds, without giving other tasks a
1090	  chance to run.  The current stack trace is displayed upon
1091	  detection and the system will stay locked up.
1092
1093config SOFTLOCKUP_DETECTOR_INTR_STORM
1094	bool "Detect Interrupt Storm in Soft Lockups"
1095	depends on SOFTLOCKUP_DETECTOR && IRQ_TIME_ACCOUNTING
1096	select GENERIC_IRQ_STAT_SNAPSHOT
1097	default y if NR_CPUS <= 128
1098	help
1099	  Say Y here to enable the kernel to detect interrupt storm
1100	  during "soft lockups".
1101
1102	  "soft lockups" can be caused by a variety of reasons. If one is
1103	  caused by an interrupt storm, then the storming interrupts will not
1104	  be on the callstack. To detect this case, it is necessary to report
1105	  the CPU stats and the interrupt counts during the "soft lockups".
1106
1107config BOOTPARAM_SOFTLOCKUP_PANIC
1108	bool "Panic (Reboot) On Soft Lockups"
1109	depends on SOFTLOCKUP_DETECTOR
1110	help
1111	  Say Y here to enable the kernel to panic on "soft lockups",
1112	  which are bugs that cause the kernel to loop in kernel
1113	  mode for more than 20 seconds (configurable using the watchdog_thresh
1114	  sysctl), without giving other tasks a chance to run.
1115
1116	  The panic can be used in combination with panic_timeout,
1117	  to cause the system to reboot automatically after a
1118	  lockup has been detected. This feature is useful for
1119	  high-availability systems that have uptime guarantees and
1120	  where a lockup must be resolved ASAP.
1121
1122	  Say N if unsure.
1123
1124config HAVE_HARDLOCKUP_DETECTOR_BUDDY
1125	bool
1126	depends on SMP
1127	default y
1128
1129#
1130# Global switch whether to build a hardlockup detector at all. It is available
1131# only when the architecture supports at least one implementation. There are
1132# two exceptions. The hardlockup detector is never enabled on:
1133#
1134#	s390: it reported many false positives there
1135#
1136#	sparc64: has a custom implementation which is not using the common
1137#		hardlockup command line options and sysctl interface.
1138#
1139config HARDLOCKUP_DETECTOR
1140	bool "Detect Hard Lockups"
1141	depends on DEBUG_KERNEL && !S390 && !HARDLOCKUP_DETECTOR_SPARC64
1142	depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_BUDDY || HAVE_HARDLOCKUP_DETECTOR_ARCH
1143	imply HARDLOCKUP_DETECTOR_PERF
1144	imply HARDLOCKUP_DETECTOR_BUDDY
1145	imply HARDLOCKUP_DETECTOR_ARCH
1146	select LOCKUP_DETECTOR
1147
1148	help
1149	  Say Y here to enable the kernel to act as a watchdog to detect
1150	  hard lockups.
1151
1152	  Hardlockups are bugs that cause the CPU to loop in kernel mode
1153	  for more than 10 seconds, without letting other interrupts have a
1154	  chance to run.  The current stack trace is displayed upon detection
1155	  and the system will stay locked up.
1156
1157#
1158# Note that arch-specific variants are always preferred.
1159#
1160config HARDLOCKUP_DETECTOR_PREFER_BUDDY
1161	bool "Prefer the buddy CPU hardlockup detector"
1162	depends on HARDLOCKUP_DETECTOR
1163	depends on HAVE_HARDLOCKUP_DETECTOR_PERF && HAVE_HARDLOCKUP_DETECTOR_BUDDY
1164	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1165	help
1166	  Say Y here to prefer the buddy hardlockup detector over the perf one.
1167
1168	  With the buddy detector, each CPU uses its softlockup hrtimer
1169	  to check that the next CPU is processing hrtimer interrupts by
1170	  verifying that a counter is increasing.
1171
1172	  This hardlockup detector is useful on systems that don't have
1173	  an arch-specific hardlockup detector or if resources needed
1174	  for the hardlockup detector are better used for other things.
1175
1176config HARDLOCKUP_DETECTOR_PERF
1177	bool
1178	depends on HARDLOCKUP_DETECTOR
1179	depends on HAVE_HARDLOCKUP_DETECTOR_PERF && !HARDLOCKUP_DETECTOR_PREFER_BUDDY
1180	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1181	select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1182
1183config HARDLOCKUP_DETECTOR_BUDDY
1184	bool
1185	depends on HARDLOCKUP_DETECTOR
1186	depends on HAVE_HARDLOCKUP_DETECTOR_BUDDY
1187	depends on !HAVE_HARDLOCKUP_DETECTOR_PERF || HARDLOCKUP_DETECTOR_PREFER_BUDDY
1188	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1189	select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1190
1191config HARDLOCKUP_DETECTOR_ARCH
1192	bool
1193	depends on HARDLOCKUP_DETECTOR
1194	depends on HAVE_HARDLOCKUP_DETECTOR_ARCH
1195	help
1196	  The arch-specific implementation of the hardlockup detector will
1197	  be used.
1198
1199#
1200# Both the "perf" and "buddy" hardlockup detectors count hrtimer
1201# interrupts. This config enables functions managing this common code.
1202#
1203config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1204	bool
1205	select SOFTLOCKUP_DETECTOR
1206
1207#
1208# Enables a timestamp based low pass filter to compensate for perf based
1209# hard lockup detection which runs too fast due to turbo modes.
1210#
1211config HARDLOCKUP_CHECK_TIMESTAMP
1212	bool
1213
1214config BOOTPARAM_HARDLOCKUP_PANIC
1215	bool "Panic (Reboot) On Hard Lockups"
1216	depends on HARDLOCKUP_DETECTOR
1217	help
1218	  Say Y here to enable the kernel to panic on "hard lockups",
1219	  which are bugs that cause the kernel to loop in kernel
1220	  mode with interrupts disabled for more than 10 seconds (configurable
1221	  using the watchdog_thresh sysctl).
1222
1223	  Say N if unsure.
1224
1225config DETECT_HUNG_TASK
1226	bool "Detect Hung Tasks"
1227	depends on DEBUG_KERNEL
1228	default SOFTLOCKUP_DETECTOR
1229	help
1230	  Say Y here to enable the kernel to detect "hung tasks",
1231	  which are bugs that cause the task to be stuck in
1232	  uninterruptible "D" state indefinitely.
1233
1234	  When a hung task is detected, the kernel will print the
1235	  current stack trace (which you should report), but the
1236	  task will stay in uninterruptible state. If lockdep is
1237	  enabled then all held locks will also be reported. This
1238	  feature has negligible overhead.
1239
1240config DEFAULT_HUNG_TASK_TIMEOUT
1241	int "Default timeout for hung task detection (in seconds)"
1242	depends on DETECT_HUNG_TASK
1243	default 120
1244	help
1245	  This option controls the default timeout (in seconds) used
1246	  to determine when a task has become non-responsive and should
1247	  be considered hung.
1248
1249	  It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1250	  sysctl or by writing a value to
1251	  /proc/sys/kernel/hung_task_timeout_secs.
1252
1253	  A timeout of 0 disables the check.  The default is two minutes.
1254	  Keeping the default should be fine in most cases.
1255
1256config BOOTPARAM_HUNG_TASK_PANIC
1257	bool "Panic (Reboot) On Hung Tasks"
1258	depends on DETECT_HUNG_TASK
1259	help
1260	  Say Y here to enable the kernel to panic on "hung tasks",
1261	  which are bugs that cause the kernel to leave a task stuck
1262	  in uninterruptible "D" state.
1263
1264	  The panic can be used in combination with panic_timeout,
1265	  to cause the system to reboot automatically after a
1266	  hung task has been detected. This feature is useful for
1267	  high-availability systems that have uptime guarantees and
1268	  where a hung tasks must be resolved ASAP.
1269
1270	  Say N if unsure.
1271
1272config WQ_WATCHDOG
1273	bool "Detect Workqueue Stalls"
1274	depends on DEBUG_KERNEL
1275	help
1276	  Say Y here to enable stall detection on workqueues.  If a
1277	  worker pool doesn't make forward progress on a pending work
1278	  item for over a given amount of time, 30s by default, a
1279	  warning message is printed along with dump of workqueue
1280	  state.  This can be configured through kernel parameter
1281	  "workqueue.watchdog_thresh" and its sysfs counterpart.
1282
1283config WQ_CPU_INTENSIVE_REPORT
1284	bool "Report per-cpu work items which hog CPU for too long"
1285	depends on DEBUG_KERNEL
1286	help
1287	  Say Y here to enable reporting of concurrency-managed per-cpu work
1288	  items that hog CPUs for longer than
1289	  workqueue.cpu_intensive_thresh_us. Workqueue automatically
1290	  detects and excludes them from concurrency management to prevent
1291	  them from stalling other per-cpu work items. Occassional
1292	  triggering may not necessarily indicate a problem. Repeated
1293	  triggering likely indicates that the work item should be switched
1294	  to use an unbound workqueue.
1295
1296config TEST_LOCKUP
1297	tristate "Test module to generate lockups"
1298	depends on m
1299	help
1300	  This builds the "test_lockup" module that helps to make sure
1301	  that watchdogs and lockup detectors are working properly.
1302
1303	  Depending on module parameters it could emulate soft or hard
1304	  lockup, "hung task", or locking arbitrary lock for a long time.
1305	  Also it could generate series of lockups with cooling-down periods.
1306
1307	  If unsure, say N.
1308
1309endmenu # "Debug lockups and hangs"
1310
1311menu "Scheduler Debugging"
1312
1313config SCHED_DEBUG
1314	bool "Collect scheduler debugging info"
1315	depends on DEBUG_KERNEL && DEBUG_FS
1316	default y
1317	help
1318	  If you say Y here, the /sys/kernel/debug/sched file will be provided
1319	  that can help debug the scheduler. The runtime overhead of this
1320	  option is minimal.
1321
1322config SCHED_INFO
1323	bool
1324	default n
1325
1326config SCHEDSTATS
1327	bool "Collect scheduler statistics"
1328	depends on PROC_FS
1329	select SCHED_INFO
1330	help
1331	  If you say Y here, additional code will be inserted into the
1332	  scheduler and related routines to collect statistics about
1333	  scheduler behavior and provide them in /proc/schedstat.  These
1334	  stats may be useful for both tuning and debugging the scheduler
1335	  If you aren't debugging the scheduler or trying to tune a specific
1336	  application, you can say N to avoid the very slight overhead
1337	  this adds.
1338
1339endmenu
1340
1341config DEBUG_PREEMPT
1342	bool "Debug preemptible kernel"
1343	depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1344	help
1345	  If you say Y here then the kernel will use a debug variant of the
1346	  commonly used smp_processor_id() function and will print warnings
1347	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
1348	  will detect preemption count underflows.
1349
1350	  This option has potential to introduce high runtime overhead,
1351	  depending on workload as it triggers debugging routines for each
1352	  this_cpu operation. It should only be used for debugging purposes.
1353
1354menu "Lock Debugging (spinlocks, mutexes, etc...)"
1355
1356config LOCK_DEBUGGING_SUPPORT
1357	bool
1358	depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1359	default y
1360
1361config PROVE_LOCKING
1362	bool "Lock debugging: prove locking correctness"
1363	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1364	select LOCKDEP
1365	select DEBUG_SPINLOCK
1366	select DEBUG_MUTEXES if !PREEMPT_RT
1367	select DEBUG_RT_MUTEXES if RT_MUTEXES
1368	select DEBUG_RWSEMS if !PREEMPT_RT
1369	select DEBUG_WW_MUTEX_SLOWPATH
1370	select DEBUG_LOCK_ALLOC
1371	select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1372	select TRACE_IRQFLAGS
1373	default n
1374	help
1375	 This feature enables the kernel to prove that all locking
1376	 that occurs in the kernel runtime is mathematically
1377	 correct: that under no circumstance could an arbitrary (and
1378	 not yet triggered) combination of observed locking
1379	 sequences (on an arbitrary number of CPUs, running an
1380	 arbitrary number of tasks and interrupt contexts) cause a
1381	 deadlock.
1382
1383	 In short, this feature enables the kernel to report locking
1384	 related deadlocks before they actually occur.
1385
1386	 The proof does not depend on how hard and complex a
1387	 deadlock scenario would be to trigger: how many
1388	 participant CPUs, tasks and irq-contexts would be needed
1389	 for it to trigger. The proof also does not depend on
1390	 timing: if a race and a resulting deadlock is possible
1391	 theoretically (no matter how unlikely the race scenario
1392	 is), it will be proven so and will immediately be
1393	 reported by the kernel (once the event is observed that
1394	 makes the deadlock theoretically possible).
1395
1396	 If a deadlock is impossible (i.e. the locking rules, as
1397	 observed by the kernel, are mathematically correct), the
1398	 kernel reports nothing.
1399
1400	 NOTE: this feature can also be enabled for rwlocks, mutexes
1401	 and rwsems - in which case all dependencies between these
1402	 different locking variants are observed and mapped too, and
1403	 the proof of observed correctness is also maintained for an
1404	 arbitrary combination of these separate locking variants.
1405
1406	 For more details, see Documentation/locking/lockdep-design.rst.
1407
1408config PROVE_RAW_LOCK_NESTING
1409	bool "Enable raw_spinlock - spinlock nesting checks" if !ARCH_SUPPORTS_RT
1410	depends on PROVE_LOCKING
1411	default y if ARCH_SUPPORTS_RT
1412	help
1413	 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1414	 that the lock nesting rules for PREEMPT_RT enabled kernels are
1415	 not violated.
1416
1417config LOCK_STAT
1418	bool "Lock usage statistics"
1419	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1420	select LOCKDEP
1421	select DEBUG_SPINLOCK
1422	select DEBUG_MUTEXES if !PREEMPT_RT
1423	select DEBUG_RT_MUTEXES if RT_MUTEXES
1424	select DEBUG_LOCK_ALLOC
1425	default n
1426	help
1427	 This feature enables tracking lock contention points
1428
1429	 For more details, see Documentation/locking/lockstat.rst
1430
1431	 This also enables lock events required by "perf lock",
1432	 subcommand of perf.
1433	 If you want to use "perf lock", you also need to turn on
1434	 CONFIG_EVENT_TRACING.
1435
1436	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1437	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1438
1439config DEBUG_RT_MUTEXES
1440	bool "RT Mutex debugging, deadlock detection"
1441	depends on DEBUG_KERNEL && RT_MUTEXES
1442	help
1443	 This allows rt mutex semantics violations and rt mutex related
1444	 deadlocks (lockups) to be detected and reported automatically.
1445
1446config DEBUG_SPINLOCK
1447	bool "Spinlock and rw-lock debugging: basic checks"
1448	depends on DEBUG_KERNEL
1449	select UNINLINE_SPIN_UNLOCK
1450	help
1451	  Say Y here and build SMP to catch missing spinlock initialization
1452	  and certain other kinds of spinlock errors commonly made.  This is
1453	  best used in conjunction with the NMI watchdog so that spinlock
1454	  deadlocks are also debuggable.
1455
1456config DEBUG_MUTEXES
1457	bool "Mutex debugging: basic checks"
1458	depends on DEBUG_KERNEL && !PREEMPT_RT
1459	help
1460	 This feature allows mutex semantics violations to be detected and
1461	 reported.
1462
1463config DEBUG_WW_MUTEX_SLOWPATH
1464	bool "Wait/wound mutex debugging: Slowpath testing"
1465	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1466	select DEBUG_LOCK_ALLOC
1467	select DEBUG_SPINLOCK
1468	select DEBUG_MUTEXES if !PREEMPT_RT
1469	select DEBUG_RT_MUTEXES if PREEMPT_RT
1470	help
1471	 This feature enables slowpath testing for w/w mutex users by
1472	 injecting additional -EDEADLK wound/backoff cases. Together with
1473	 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1474	 will test all possible w/w mutex interface abuse with the
1475	 exception of simply not acquiring all the required locks.
1476	 Note that this feature can introduce significant overhead, so
1477	 it really should not be enabled in a production or distro kernel,
1478	 even a debug kernel.  If you are a driver writer, enable it.  If
1479	 you are a distro, do not.
1480
1481config DEBUG_RWSEMS
1482	bool "RW Semaphore debugging: basic checks"
1483	depends on DEBUG_KERNEL && !PREEMPT_RT
1484	help
1485	  This debugging feature allows mismatched rw semaphore locks
1486	  and unlocks to be detected and reported.
1487
1488config DEBUG_LOCK_ALLOC
1489	bool "Lock debugging: detect incorrect freeing of live locks"
1490	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1491	select DEBUG_SPINLOCK
1492	select DEBUG_MUTEXES if !PREEMPT_RT
1493	select DEBUG_RT_MUTEXES if RT_MUTEXES
1494	select LOCKDEP
1495	help
1496	 This feature will check whether any held lock (spinlock, rwlock,
1497	 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1498	 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1499	 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1500	 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1501	 held during task exit.
1502
1503config LOCKDEP
1504	bool
1505	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1506	select STACKTRACE
1507	select KALLSYMS
1508	select KALLSYMS_ALL
1509
1510config LOCKDEP_SMALL
1511	bool
1512
1513config LOCKDEP_BITS
1514	int "Size for MAX_LOCKDEP_ENTRIES (as Nth power of 2)"
1515	depends on LOCKDEP && !LOCKDEP_SMALL
1516	range 10 24
1517	default 15
1518	help
1519	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1520
1521config LOCKDEP_CHAINS_BITS
1522	int "Size for MAX_LOCKDEP_CHAINS (as Nth power of 2)"
1523	depends on LOCKDEP && !LOCKDEP_SMALL
1524	range 10 21
1525	default 16
1526	help
1527	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1528
1529config LOCKDEP_STACK_TRACE_BITS
1530	int "Size for MAX_STACK_TRACE_ENTRIES (as Nth power of 2)"
1531	depends on LOCKDEP && !LOCKDEP_SMALL
1532	range 10 26
1533	default 19
1534	help
1535	  Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1536
1537config LOCKDEP_STACK_TRACE_HASH_BITS
1538	int "Size for STACK_TRACE_HASH_SIZE (as Nth power of 2)"
1539	depends on LOCKDEP && !LOCKDEP_SMALL
1540	range 10 26
1541	default 14
1542	help
1543	  Try increasing this value if you need large STACK_TRACE_HASH_SIZE.
1544
1545config LOCKDEP_CIRCULAR_QUEUE_BITS
1546	int "Size for elements in circular_queue struct (as Nth power of 2)"
1547	depends on LOCKDEP
1548	range 10 26
1549	default 12
1550	help
1551	  Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1552
1553config DEBUG_LOCKDEP
1554	bool "Lock dependency engine debugging"
1555	depends on DEBUG_KERNEL && LOCKDEP
1556	select DEBUG_IRQFLAGS
1557	help
1558	  If you say Y here, the lock dependency engine will do
1559	  additional runtime checks to debug itself, at the price
1560	  of more runtime overhead.
1561
1562config DEBUG_ATOMIC_SLEEP
1563	bool "Sleep inside atomic section checking"
1564	select PREEMPT_COUNT
1565	depends on DEBUG_KERNEL
1566	depends on !ARCH_NO_PREEMPT
1567	help
1568	  If you say Y here, various routines which may sleep will become very
1569	  noisy if they are called inside atomic sections: when a spinlock is
1570	  held, inside an rcu read side critical section, inside preempt disabled
1571	  sections, inside an interrupt, etc...
1572
1573config DEBUG_LOCKING_API_SELFTESTS
1574	bool "Locking API boot-time self-tests"
1575	depends on DEBUG_KERNEL
1576	help
1577	  Say Y here if you want the kernel to run a short self-test during
1578	  bootup. The self-test checks whether common types of locking bugs
1579	  are detected by debugging mechanisms or not. (if you disable
1580	  lock debugging then those bugs won't be detected of course.)
1581	  The following locking APIs are covered: spinlocks, rwlocks,
1582	  mutexes and rwsems.
1583
1584config LOCK_TORTURE_TEST
1585	tristate "torture tests for locking"
1586	depends on DEBUG_KERNEL
1587	select TORTURE_TEST
1588	help
1589	  This option provides a kernel module that runs torture tests
1590	  on kernel locking primitives.  The kernel module may be built
1591	  after the fact on the running kernel to be tested, if desired.
1592
1593	  Say Y here if you want kernel locking-primitive torture tests
1594	  to be built into the kernel.
1595	  Say M if you want these torture tests to build as a module.
1596	  Say N if you are unsure.
1597
1598config WW_MUTEX_SELFTEST
1599	tristate "Wait/wound mutex selftests"
1600	help
1601	  This option provides a kernel module that runs tests on the
1602	  on the struct ww_mutex locking API.
1603
1604	  It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1605	  with this test harness.
1606
1607	  Say M if you want these self tests to build as a module.
1608	  Say N if you are unsure.
1609
1610config SCF_TORTURE_TEST
1611	tristate "torture tests for smp_call_function*()"
1612	depends on DEBUG_KERNEL
1613	select TORTURE_TEST
1614	help
1615	  This option provides a kernel module that runs torture tests
1616	  on the smp_call_function() family of primitives.  The kernel
1617	  module may be built after the fact on the running kernel to
1618	  be tested, if desired.
1619
1620config CSD_LOCK_WAIT_DEBUG
1621	bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1622	depends on DEBUG_KERNEL
1623	depends on SMP
1624	depends on 64BIT
1625	default n
1626	help
1627	  This option enables debug prints when CPUs are slow to respond
1628	  to the smp_call_function*() IPI wrappers.  These debug prints
1629	  include the IPI handler function currently executing (if any)
1630	  and relevant stack traces.
1631
1632config CSD_LOCK_WAIT_DEBUG_DEFAULT
1633	bool "Default csd_lock_wait() debugging on at boot time"
1634	depends on CSD_LOCK_WAIT_DEBUG
1635	depends on 64BIT
1636	default n
1637	help
1638	  This option causes the csdlock_debug= kernel boot parameter to
1639	  default to 1 (basic debugging) instead of 0 (no debugging).
1640
1641endmenu # lock debugging
1642
1643config TRACE_IRQFLAGS
1644	depends on TRACE_IRQFLAGS_SUPPORT
1645	bool
1646	help
1647	  Enables hooks to interrupt enabling and disabling for
1648	  either tracing or lock debugging.
1649
1650config TRACE_IRQFLAGS_NMI
1651	def_bool y
1652	depends on TRACE_IRQFLAGS
1653	depends on TRACE_IRQFLAGS_NMI_SUPPORT
1654
1655config NMI_CHECK_CPU
1656	bool "Debugging for CPUs failing to respond to backtrace requests"
1657	depends on DEBUG_KERNEL
1658	depends on X86
1659	default n
1660	help
1661	  Enables debug prints when a CPU fails to respond to a given
1662	  backtrace NMI.  These prints provide some reasons why a CPU
1663	  might legitimately be failing to respond, for example, if it
1664	  is offline of if ignore_nmis is set.
1665
1666config DEBUG_IRQFLAGS
1667	bool "Debug IRQ flag manipulation"
1668	help
1669	  Enables checks for potentially unsafe enabling or disabling of
1670	  interrupts, such as calling raw_local_irq_restore() when interrupts
1671	  are enabled.
1672
1673config STACKTRACE
1674	bool "Stack backtrace support"
1675	depends on STACKTRACE_SUPPORT
1676	help
1677	  This option causes the kernel to create a /proc/pid/stack for
1678	  every process, showing its current stack trace.
1679	  It is also used by various kernel debugging features that require
1680	  stack trace generation.
1681
1682config WARN_ALL_UNSEEDED_RANDOM
1683	bool "Warn for all uses of unseeded randomness"
1684	default n
1685	help
1686	  Some parts of the kernel contain bugs relating to their use of
1687	  cryptographically secure random numbers before it's actually possible
1688	  to generate those numbers securely. This setting ensures that these
1689	  flaws don't go unnoticed, by enabling a message, should this ever
1690	  occur. This will allow people with obscure setups to know when things
1691	  are going wrong, so that they might contact developers about fixing
1692	  it.
1693
1694	  Unfortunately, on some models of some architectures getting
1695	  a fully seeded CRNG is extremely difficult, and so this can
1696	  result in dmesg getting spammed for a surprisingly long
1697	  time.  This is really bad from a security perspective, and
1698	  so architecture maintainers really need to do what they can
1699	  to get the CRNG seeded sooner after the system is booted.
1700	  However, since users cannot do anything actionable to
1701	  address this, by default this option is disabled.
1702
1703	  Say Y here if you want to receive warnings for all uses of
1704	  unseeded randomness.  This will be of use primarily for
1705	  those developers interested in improving the security of
1706	  Linux kernels running on their architecture (or
1707	  subarchitecture).
1708
1709config DEBUG_KOBJECT
1710	bool "kobject debugging"
1711	depends on DEBUG_KERNEL
1712	help
1713	  If you say Y here, some extra kobject debugging messages will be sent
1714	  to the syslog.
1715
1716config DEBUG_KOBJECT_RELEASE
1717	bool "kobject release debugging"
1718	depends on DEBUG_OBJECTS_TIMERS
1719	help
1720	  kobjects are reference counted objects.  This means that their
1721	  last reference count put is not predictable, and the kobject can
1722	  live on past the point at which a driver decides to drop its
1723	  initial reference to the kobject gained on allocation.  An
1724	  example of this would be a struct device which has just been
1725	  unregistered.
1726
1727	  However, some buggy drivers assume that after such an operation,
1728	  the memory backing the kobject can be immediately freed.  This
1729	  goes completely against the principles of a refcounted object.
1730
1731	  If you say Y here, the kernel will delay the release of kobjects
1732	  on the last reference count to improve the visibility of this
1733	  kind of kobject release bug.
1734
1735config HAVE_DEBUG_BUGVERBOSE
1736	bool
1737
1738menu "Debug kernel data structures"
1739
1740config DEBUG_LIST
1741	bool "Debug linked list manipulation"
1742	depends on DEBUG_KERNEL
1743	select LIST_HARDENED
1744	help
1745	  Enable this to turn on extended checks in the linked-list walking
1746	  routines.
1747
1748	  This option trades better quality error reports for performance, and
1749	  is more suitable for kernel debugging. If you care about performance,
1750	  you should only enable CONFIG_LIST_HARDENED instead.
1751
1752	  If unsure, say N.
1753
1754config DEBUG_PLIST
1755	bool "Debug priority linked list manipulation"
1756	depends on DEBUG_KERNEL
1757	help
1758	  Enable this to turn on extended checks in the priority-ordered
1759	  linked-list (plist) walking routines.  This checks the entire
1760	  list multiple times during each manipulation.
1761
1762	  If unsure, say N.
1763
1764config DEBUG_SG
1765	bool "Debug SG table operations"
1766	depends on DEBUG_KERNEL
1767	help
1768	  Enable this to turn on checks on scatter-gather tables. This can
1769	  help find problems with drivers that do not properly initialize
1770	  their sg tables.
1771
1772	  If unsure, say N.
1773
1774config DEBUG_NOTIFIERS
1775	bool "Debug notifier call chains"
1776	depends on DEBUG_KERNEL
1777	help
1778	  Enable this to turn on sanity checking for notifier call chains.
1779	  This is most useful for kernel developers to make sure that
1780	  modules properly unregister themselves from notifier chains.
1781	  This is a relatively cheap check but if you care about maximum
1782	  performance, say N.
1783
1784config DEBUG_CLOSURES
1785	bool "Debug closures (bcache async widgits)"
1786	depends on CLOSURES
1787	select DEBUG_FS
1788	help
1789	  Keeps all active closures in a linked list and provides a debugfs
1790	  interface to list them, which makes it possible to see asynchronous
1791	  operations that get stuck.
1792
1793config DEBUG_MAPLE_TREE
1794	bool "Debug maple trees"
1795	depends on DEBUG_KERNEL
1796	help
1797	  Enable maple tree debugging information and extra validations.
1798
1799	  If unsure, say N.
1800
1801endmenu
1802
1803source "kernel/rcu/Kconfig.debug"
1804
1805config DEBUG_WQ_FORCE_RR_CPU
1806	bool "Force round-robin CPU selection for unbound work items"
1807	depends on DEBUG_KERNEL
1808	default n
1809	help
1810	  Workqueue used to implicitly guarantee that work items queued
1811	  without explicit CPU specified are put on the local CPU.  This
1812	  guarantee is no longer true and while local CPU is still
1813	  preferred work items may be put on foreign CPUs.  Kernel
1814	  parameter "workqueue.debug_force_rr_cpu" is added to force
1815	  round-robin CPU selection to flush out usages which depend on the
1816	  now broken guarantee.  This config option enables the debug
1817	  feature by default.  When enabled, memory and cache locality will
1818	  be impacted.
1819
1820config CPU_HOTPLUG_STATE_CONTROL
1821	bool "Enable CPU hotplug state control"
1822	depends on DEBUG_KERNEL
1823	depends on HOTPLUG_CPU
1824	default n
1825	help
1826	  Allows to write steps between "offline" and "online" to the CPUs
1827	  sysfs target file so states can be stepped granular. This is a debug
1828	  option for now as the hotplug machinery cannot be stopped and
1829	  restarted at arbitrary points yet.
1830
1831	  Say N if your are unsure.
1832
1833config LATENCYTOP
1834	bool "Latency measuring infrastructure"
1835	depends on DEBUG_KERNEL
1836	depends on STACKTRACE_SUPPORT
1837	depends on PROC_FS
1838	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1839	select KALLSYMS
1840	select KALLSYMS_ALL
1841	select STACKTRACE
1842	select SCHEDSTATS
1843	help
1844	  Enable this option if you want to use the LatencyTOP tool
1845	  to find out which userspace is blocking on what kernel operations.
1846
1847config DEBUG_CGROUP_REF
1848	bool "Disable inlining of cgroup css reference count functions"
1849	depends on DEBUG_KERNEL
1850	depends on CGROUPS
1851	depends on KPROBES
1852	default n
1853	help
1854	  Force cgroup css reference count functions to not be inlined so
1855	  that they can be kprobed for debugging.
1856
1857source "kernel/trace/Kconfig"
1858
1859config PROVIDE_OHCI1394_DMA_INIT
1860	bool "Remote debugging over FireWire early on boot"
1861	depends on PCI && X86
1862	help
1863	  If you want to debug problems which hang or crash the kernel early
1864	  on boot and the crashing machine has a FireWire port, you can use
1865	  this feature to remotely access the memory of the crashed machine
1866	  over FireWire. This employs remote DMA as part of the OHCI1394
1867	  specification which is now the standard for FireWire controllers.
1868
1869	  With remote DMA, you can monitor the printk buffer remotely using
1870	  firescope and access all memory below 4GB using fireproxy from gdb.
1871	  Even controlling a kernel debugger is possible using remote DMA.
1872
1873	  Usage:
1874
1875	  If ohci1394_dma=early is used as boot parameter, it will initialize
1876	  all OHCI1394 controllers which are found in the PCI config space.
1877
1878	  As all changes to the FireWire bus such as enabling and disabling
1879	  devices cause a bus reset and thereby disable remote DMA for all
1880	  devices, be sure to have the cable plugged and FireWire enabled on
1881	  the debugging host before booting the debug target for debugging.
1882
1883	  This code (~1k) is freed after boot. By then, the firewire stack
1884	  in charge of the OHCI-1394 controllers should be used instead.
1885
1886	  See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1887
1888source "samples/Kconfig"
1889
1890config ARCH_HAS_DEVMEM_IS_ALLOWED
1891	bool
1892
1893config STRICT_DEVMEM
1894	bool "Filter access to /dev/mem"
1895	depends on MMU && DEVMEM
1896	depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1897	default y if PPC || X86 || ARM64 || S390
1898	help
1899	  If this option is disabled, you allow userspace (root) access to all
1900	  of memory, including kernel and userspace memory. Accidental
1901	  access to this is obviously disastrous, but specific access can
1902	  be used by people debugging the kernel. Note that with PAT support
1903	  enabled, even in this case there are restrictions on /dev/mem
1904	  use due to the cache aliasing requirements.
1905
1906	  If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1907	  file only allows userspace access to PCI space and the BIOS code and
1908	  data regions.  This is sufficient for dosemu and X and all common
1909	  users of /dev/mem.
1910
1911	  If in doubt, say Y.
1912
1913config IO_STRICT_DEVMEM
1914	bool "Filter I/O access to /dev/mem"
1915	depends on STRICT_DEVMEM
1916	help
1917	  If this option is disabled, you allow userspace (root) access to all
1918	  io-memory regardless of whether a driver is actively using that
1919	  range.  Accidental access to this is obviously disastrous, but
1920	  specific access can be used by people debugging kernel drivers.
1921
1922	  If this option is switched on, the /dev/mem file only allows
1923	  userspace access to *idle* io-memory ranges (see /proc/iomem) This
1924	  may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1925	  if the driver using a given range cannot be disabled.
1926
1927	  If in doubt, say Y.
1928
1929menu "$(SRCARCH) Debugging"
1930
1931source "arch/$(SRCARCH)/Kconfig.debug"
1932
1933endmenu
1934
1935menu "Kernel Testing and Coverage"
1936
1937source "lib/kunit/Kconfig"
1938
1939config NOTIFIER_ERROR_INJECTION
1940	tristate "Notifier error injection"
1941	depends on DEBUG_KERNEL
1942	select DEBUG_FS
1943	help
1944	  This option provides the ability to inject artificial errors to
1945	  specified notifier chain callbacks. It is useful to test the error
1946	  handling of notifier call chain failures.
1947
1948	  Say N if unsure.
1949
1950config PM_NOTIFIER_ERROR_INJECT
1951	tristate "PM notifier error injection module"
1952	depends on PM && NOTIFIER_ERROR_INJECTION
1953	default m if PM_DEBUG
1954	help
1955	  This option provides the ability to inject artificial errors to
1956	  PM notifier chain callbacks.  It is controlled through debugfs
1957	  interface /sys/kernel/debug/notifier-error-inject/pm
1958
1959	  If the notifier call chain should be failed with some events
1960	  notified, write the error code to "actions/<notifier event>/error".
1961
1962	  Example: Inject PM suspend error (-12 = -ENOMEM)
1963
1964	  # cd /sys/kernel/debug/notifier-error-inject/pm/
1965	  # echo -12 > actions/PM_SUSPEND_PREPARE/error
1966	  # echo mem > /sys/power/state
1967	  bash: echo: write error: Cannot allocate memory
1968
1969	  To compile this code as a module, choose M here: the module will
1970	  be called pm-notifier-error-inject.
1971
1972	  If unsure, say N.
1973
1974config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1975	tristate "OF reconfig notifier error injection module"
1976	depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1977	help
1978	  This option provides the ability to inject artificial errors to
1979	  OF reconfig notifier chain callbacks.  It is controlled
1980	  through debugfs interface under
1981	  /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1982
1983	  If the notifier call chain should be failed with some events
1984	  notified, write the error code to "actions/<notifier event>/error".
1985
1986	  To compile this code as a module, choose M here: the module will
1987	  be called of-reconfig-notifier-error-inject.
1988
1989	  If unsure, say N.
1990
1991config NETDEV_NOTIFIER_ERROR_INJECT
1992	tristate "Netdev notifier error injection module"
1993	depends on NET && NOTIFIER_ERROR_INJECTION
1994	help
1995	  This option provides the ability to inject artificial errors to
1996	  netdevice notifier chain callbacks.  It is controlled through debugfs
1997	  interface /sys/kernel/debug/notifier-error-inject/netdev
1998
1999	  If the notifier call chain should be failed with some events
2000	  notified, write the error code to "actions/<notifier event>/error".
2001
2002	  Example: Inject netdevice mtu change error (-22 = -EINVAL)
2003
2004	  # cd /sys/kernel/debug/notifier-error-inject/netdev
2005	  # echo -22 > actions/NETDEV_CHANGEMTU/error
2006	  # ip link set eth0 mtu 1024
2007	  RTNETLINK answers: Invalid argument
2008
2009	  To compile this code as a module, choose M here: the module will
2010	  be called netdev-notifier-error-inject.
2011
2012	  If unsure, say N.
2013
2014config FUNCTION_ERROR_INJECTION
2015	bool "Fault-injections of functions"
2016	depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
2017	help
2018	  Add fault injections into various functions that are annotated with
2019	  ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
2020	  value of these functions. This is useful to test error paths of code.
2021
2022	  If unsure, say N
2023
2024config FAULT_INJECTION
2025	bool "Fault-injection framework"
2026	depends on DEBUG_KERNEL
2027	help
2028	  Provide fault-injection framework.
2029	  For more details, see Documentation/fault-injection/.
2030
2031config FAILSLAB
2032	bool "Fault-injection capability for kmalloc"
2033	depends on FAULT_INJECTION
2034	help
2035	  Provide fault-injection capability for kmalloc.
2036
2037config FAIL_PAGE_ALLOC
2038	bool "Fault-injection capability for alloc_pages()"
2039	depends on FAULT_INJECTION
2040	help
2041	  Provide fault-injection capability for alloc_pages().
2042
2043config FAULT_INJECTION_USERCOPY
2044	bool "Fault injection capability for usercopy functions"
2045	depends on FAULT_INJECTION
2046	help
2047	  Provides fault-injection capability to inject failures
2048	  in usercopy functions (copy_from_user(), get_user(), ...).
2049
2050config FAIL_MAKE_REQUEST
2051	bool "Fault-injection capability for disk IO"
2052	depends on FAULT_INJECTION && BLOCK
2053	help
2054	  Provide fault-injection capability for disk IO.
2055
2056config FAIL_IO_TIMEOUT
2057	bool "Fault-injection capability for faking disk interrupts"
2058	depends on FAULT_INJECTION && BLOCK
2059	help
2060	  Provide fault-injection capability on end IO handling. This
2061	  will make the block layer "forget" an interrupt as configured,
2062	  thus exercising the error handling.
2063
2064	  Only works with drivers that use the generic timeout handling,
2065	  for others it won't do anything.
2066
2067config FAIL_FUTEX
2068	bool "Fault-injection capability for futexes"
2069	select DEBUG_FS
2070	depends on FAULT_INJECTION && FUTEX
2071	help
2072	  Provide fault-injection capability for futexes.
2073
2074config FAULT_INJECTION_DEBUG_FS
2075	bool "Debugfs entries for fault-injection capabilities"
2076	depends on FAULT_INJECTION && SYSFS && DEBUG_FS
2077	help
2078	  Enable configuration of fault-injection capabilities via debugfs.
2079
2080config FAIL_FUNCTION
2081	bool "Fault-injection capability for functions"
2082	depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
2083	help
2084	  Provide function-based fault-injection capability.
2085	  This will allow you to override a specific function with a return
2086	  with given return value. As a result, function caller will see
2087	  an error value and have to handle it. This is useful to test the
2088	  error handling in various subsystems.
2089
2090config FAIL_MMC_REQUEST
2091	bool "Fault-injection capability for MMC IO"
2092	depends on FAULT_INJECTION_DEBUG_FS && MMC
2093	help
2094	  Provide fault-injection capability for MMC IO.
2095	  This will make the mmc core return data errors. This is
2096	  useful to test the error handling in the mmc block device
2097	  and to test how the mmc host driver handles retries from
2098	  the block device.
2099
2100config FAIL_SUNRPC
2101	bool "Fault-injection capability for SunRPC"
2102	depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2103	help
2104	  Provide fault-injection capability for SunRPC and
2105	  its consumers.
2106
2107config FAIL_SKB_REALLOC
2108	bool "Fault-injection capability forcing skb to reallocate"
2109	depends on FAULT_INJECTION_DEBUG_FS
2110	help
2111	  Provide fault-injection capability that forces the skb to be
2112	  reallocated, catching possible invalid pointers to the skb.
2113
2114	  For more information, check
2115	  Documentation/dev-tools/fault-injection/fault-injection.rst
2116
2117config FAULT_INJECTION_CONFIGFS
2118	bool "Configfs interface for fault-injection capabilities"
2119	depends on FAULT_INJECTION
2120	select CONFIGFS_FS
2121	help
2122	  This option allows configfs-based drivers to dynamically configure
2123	  fault-injection via configfs.  Each parameter for driver-specific
2124	  fault-injection can be made visible as a configfs attribute in a
2125	  configfs group.
2126
2127
2128config FAULT_INJECTION_STACKTRACE_FILTER
2129	bool "stacktrace filter for fault-injection capabilities"
2130	depends on FAULT_INJECTION
2131	depends on (FAULT_INJECTION_DEBUG_FS || FAULT_INJECTION_CONFIGFS) && STACKTRACE_SUPPORT
2132	select STACKTRACE
2133	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2134	help
2135	  Provide stacktrace filter for fault-injection capabilities
2136
2137config ARCH_HAS_KCOV
2138	bool
2139	help
2140	  An architecture should select this when it can successfully
2141	  build and run with CONFIG_KCOV. This typically requires
2142	  disabling instrumentation for some early boot code.
2143
2144config CC_HAS_SANCOV_TRACE_PC
2145	def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2146
2147
2148config KCOV
2149	bool "Code coverage for fuzzing"
2150	depends on ARCH_HAS_KCOV
2151	depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2152	depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2153		   GCC_VERSION >= 120000 || CC_IS_CLANG
2154	select DEBUG_FS
2155	select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2156	select OBJTOOL if HAVE_NOINSTR_HACK
2157	help
2158	  KCOV exposes kernel code coverage information in a form suitable
2159	  for coverage-guided fuzzing (randomized testing).
2160
2161	  For more details, see Documentation/dev-tools/kcov.rst.
2162
2163config KCOV_ENABLE_COMPARISONS
2164	bool "Enable comparison operands collection by KCOV"
2165	depends on KCOV
2166	depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2167	help
2168	  KCOV also exposes operands of every comparison in the instrumented
2169	  code along with operand sizes and PCs of the comparison instructions.
2170	  These operands can be used by fuzzing engines to improve the quality
2171	  of fuzzing coverage.
2172
2173config KCOV_INSTRUMENT_ALL
2174	bool "Instrument all code by default"
2175	depends on KCOV
2176	default y
2177	help
2178	  If you are doing generic system call fuzzing (like e.g. syzkaller),
2179	  then you will want to instrument the whole kernel and you should
2180	  say y here. If you are doing more targeted fuzzing (like e.g.
2181	  filesystem fuzzing with AFL) then you will want to enable coverage
2182	  for more specific subsets of files, and should say n here.
2183
2184config KCOV_IRQ_AREA_SIZE
2185	hex "Size of interrupt coverage collection area in words"
2186	depends on KCOV
2187	default 0x40000
2188	help
2189	  KCOV uses preallocated per-cpu areas to collect coverage from
2190	  soft interrupts. This specifies the size of those areas in the
2191	  number of unsigned long words.
2192
2193config KCOV_SELFTEST
2194	bool "Perform short selftests on boot"
2195	depends on KCOV
2196	help
2197	  Run short KCOV coverage collection selftests on boot.
2198	  On test failure, causes the kernel to panic. Recommended to be
2199	  enabled, ensuring critical functionality works as intended.
2200
2201menuconfig RUNTIME_TESTING_MENU
2202	bool "Runtime Testing"
2203	default y
2204
2205if RUNTIME_TESTING_MENU
2206
2207config TEST_DHRY
2208	tristate "Dhrystone benchmark test"
2209	help
2210	  Enable this to include the Dhrystone 2.1 benchmark.  This test
2211	  calculates the number of Dhrystones per second, and the number of
2212	  DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided
2213	  by 1757 (the number of Dhrystones per second obtained on the VAX
2214	  11/780, nominally a 1 MIPS machine).
2215
2216	  To run the benchmark, it needs to be enabled explicitly, either from
2217	  the kernel command line (when built-in), or from userspace (when
2218	  built-in or modular).
2219
2220	  Run once during kernel boot:
2221
2222	      test_dhry.run
2223
2224	  Set number of iterations from kernel command line:
2225
2226	      test_dhry.iterations=<n>
2227
2228	  Set number of iterations from userspace:
2229
2230	      echo <n> > /sys/module/test_dhry/parameters/iterations
2231
2232	  Trigger manual run from userspace:
2233
2234	      echo y > /sys/module/test_dhry/parameters/run
2235
2236	  If the number of iterations is <= 0, the test will devise a suitable
2237	  number of iterations (test runs for at least 2s) automatically.
2238	  This process takes ca. 4s.
2239
2240	  If unsure, say N.
2241
2242config LKDTM
2243	tristate "Linux Kernel Dump Test Tool Module"
2244	depends on DEBUG_FS
2245	help
2246	This module enables testing of the different dumping mechanisms by
2247	inducing system failures at predefined crash points.
2248	If you don't need it: say N
2249	Choose M here to compile this code as a module. The module will be
2250	called lkdtm.
2251
2252	Documentation on how to use the module can be found in
2253	Documentation/fault-injection/provoke-crashes.rst
2254
2255config CPUMASK_KUNIT_TEST
2256	tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2257	depends on KUNIT
2258	default KUNIT_ALL_TESTS
2259	help
2260	  Enable to turn on cpumask tests, running at boot or module load time.
2261
2262	  For more information on KUnit and unit tests in general, please refer
2263	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2264
2265	  If unsure, say N.
2266
2267config TEST_LIST_SORT
2268	tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2269	depends on KUNIT
2270	default KUNIT_ALL_TESTS
2271	help
2272	  Enable this to turn on 'list_sort()' function test. This test is
2273	  executed only once during system boot (so affects only boot time),
2274	  or at module load time.
2275
2276	  If unsure, say N.
2277
2278config TEST_MIN_HEAP
2279	tristate "Min heap test"
2280	depends on DEBUG_KERNEL || m
2281	help
2282	  Enable this to turn on min heap function tests. This test is
2283	  executed only once during system boot (so affects only boot time),
2284	  or at module load time.
2285
2286	  If unsure, say N.
2287
2288config TEST_SORT
2289	tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2290	depends on KUNIT
2291	default KUNIT_ALL_TESTS
2292	help
2293	  This option enables the self-test function of 'sort()' at boot,
2294	  or at module load time.
2295
2296	  If unsure, say N.
2297
2298config TEST_DIV64
2299	tristate "64bit/32bit division and modulo test"
2300	depends on DEBUG_KERNEL || m
2301	help
2302	  Enable this to turn on 'do_div()' function test. This test is
2303	  executed only once during system boot (so affects only boot time),
2304	  or at module load time.
2305
2306	  If unsure, say N.
2307
2308config TEST_MULDIV64
2309	tristate "mul_u64_u64_div_u64() test"
2310	depends on DEBUG_KERNEL || m
2311	help
2312	  Enable this to turn on 'mul_u64_u64_div_u64()' function test.
2313	  This test is executed only once during system boot (so affects
2314	  only boot time), or at module load time.
2315
2316	  If unsure, say N.
2317
2318config TEST_IOV_ITER
2319	tristate "Test iov_iter operation" if !KUNIT_ALL_TESTS
2320	depends on KUNIT
2321	depends on MMU
2322	default KUNIT_ALL_TESTS
2323	help
2324	  Enable this to turn on testing of the operation of the I/O iterator
2325	  (iov_iter). This test is executed only once during system boot (so
2326	  affects only boot time), or at module load time.
2327
2328	  If unsure, say N.
2329
2330config KPROBES_SANITY_TEST
2331	tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2332	depends on DEBUG_KERNEL
2333	depends on KPROBES
2334	depends on KUNIT
2335	select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2336	default KUNIT_ALL_TESTS
2337	help
2338	  This option provides for testing basic kprobes functionality on
2339	  boot. Samples of kprobe and kretprobe are inserted and
2340	  verified for functionality.
2341
2342	  Say N if you are unsure.
2343
2344config FPROBE_SANITY_TEST
2345	bool "Self test for fprobe"
2346	depends on DEBUG_KERNEL
2347	depends on FPROBE
2348	depends on KUNIT=y
2349	help
2350	  This option will enable testing the fprobe when the system boot.
2351	  A series of tests are made to verify that the fprobe is functioning
2352	  properly.
2353
2354	  Say N if you are unsure.
2355
2356config BACKTRACE_SELF_TEST
2357	tristate "Self test for the backtrace code"
2358	depends on DEBUG_KERNEL
2359	help
2360	  This option provides a kernel module that can be used to test
2361	  the kernel stack backtrace code. This option is not useful
2362	  for distributions or general kernels, but only for kernel
2363	  developers working on architecture code.
2364
2365	  Note that if you want to also test saved backtraces, you will
2366	  have to enable STACKTRACE as well.
2367
2368	  Say N if you are unsure.
2369
2370config TEST_REF_TRACKER
2371	tristate "Self test for reference tracker"
2372	depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2373	select REF_TRACKER
2374	help
2375	  This option provides a kernel module performing tests
2376	  using reference tracker infrastructure.
2377
2378	  Say N if you are unsure.
2379
2380config RBTREE_TEST
2381	tristate "Red-Black tree test"
2382	depends on DEBUG_KERNEL
2383	help
2384	  A benchmark measuring the performance of the rbtree library.
2385	  Also includes rbtree invariant checks.
2386
2387config REED_SOLOMON_TEST
2388	tristate "Reed-Solomon library test"
2389	depends on DEBUG_KERNEL || m
2390	select REED_SOLOMON
2391	select REED_SOLOMON_ENC16
2392	select REED_SOLOMON_DEC16
2393	help
2394	  This option enables the self-test function of rslib at boot,
2395	  or at module load time.
2396
2397	  If unsure, say N.
2398
2399config INTERVAL_TREE_TEST
2400	tristate "Interval tree test"
2401	depends on DEBUG_KERNEL
2402	select INTERVAL_TREE
2403	help
2404	  A benchmark measuring the performance of the interval tree library
2405
2406config PERCPU_TEST
2407	tristate "Per cpu operations test"
2408	depends on m && DEBUG_KERNEL
2409	help
2410	  Enable this option to build test module which validates per-cpu
2411	  operations.
2412
2413	  If unsure, say N.
2414
2415config ATOMIC64_SELFTEST
2416	tristate "Perform an atomic64_t self-test"
2417	help
2418	  Enable this option to test the atomic64_t functions at boot or
2419	  at module load time.
2420
2421	  If unsure, say N.
2422
2423config ASYNC_RAID6_TEST
2424	tristate "Self test for hardware accelerated raid6 recovery"
2425	depends on ASYNC_RAID6_RECOV
2426	select ASYNC_MEMCPY
2427	help
2428	  This is a one-shot self test that permutes through the
2429	  recovery of all the possible two disk failure scenarios for a
2430	  N-disk array.  Recovery is performed with the asynchronous
2431	  raid6 recovery routines, and will optionally use an offload
2432	  engine if one is available.
2433
2434	  If unsure, say N.
2435
2436config TEST_HEXDUMP
2437	tristate "Test functions located in the hexdump module at runtime"
2438
2439config STRING_KUNIT_TEST
2440	tristate "KUnit test string functions at runtime" if !KUNIT_ALL_TESTS
2441	depends on KUNIT
2442	default KUNIT_ALL_TESTS
2443
2444config STRING_HELPERS_KUNIT_TEST
2445	tristate "KUnit test string helpers at runtime" if !KUNIT_ALL_TESTS
2446	depends on KUNIT
2447	default KUNIT_ALL_TESTS
2448
2449config TEST_KSTRTOX
2450	tristate "Test kstrto*() family of functions at runtime"
2451
2452config TEST_PRINTF
2453	tristate "Test printf() family of functions at runtime"
2454
2455config TEST_SCANF
2456	tristate "Test scanf() family of functions at runtime"
2457
2458config TEST_BITMAP
2459	tristate "Test bitmap_*() family of functions at runtime"
2460	help
2461	  Enable this option to test the bitmap functions at boot.
2462
2463	  If unsure, say N.
2464
2465config TEST_UUID
2466	tristate "Test functions located in the uuid module at runtime"
2467
2468config TEST_XARRAY
2469	tristate "Test the XArray code at runtime"
2470
2471config TEST_MAPLE_TREE
2472	tristate "Test the Maple Tree code at runtime or module load"
2473	help
2474	  Enable this option to test the maple tree code functions at boot, or
2475	  when the module is loaded. Enable "Debug Maple Trees" will enable
2476	  more verbose output on failures.
2477
2478	  If unsure, say N.
2479
2480config TEST_RHASHTABLE
2481	tristate "Perform selftest on resizable hash table"
2482	help
2483	  Enable this option to test the rhashtable functions at boot.
2484
2485	  If unsure, say N.
2486
2487config TEST_IDA
2488	tristate "Perform selftest on IDA functions"
2489
2490config TEST_MISC_MINOR
2491	tristate "Basic misc minor Kunit test" if !KUNIT_ALL_TESTS
2492	depends on KUNIT
2493	default KUNIT_ALL_TESTS
2494	help
2495	  Kunit test for the misc minor.
2496	  It tests misc minor functions for dynamic and misc dynamic minor.
2497	  This include misc_xxx functions
2498
2499	  If unsure, say N.
2500
2501config TEST_PARMAN
2502	tristate "Perform selftest on priority array manager"
2503	depends on PARMAN
2504	help
2505	  Enable this option to test priority array manager on boot
2506	  (or module load).
2507
2508	  If unsure, say N.
2509
2510config TEST_IRQ_TIMINGS
2511	bool "IRQ timings selftest"
2512	depends on IRQ_TIMINGS
2513	help
2514	  Enable this option to test the irq timings code on boot.
2515
2516	  If unsure, say N.
2517
2518config TEST_LKM
2519	tristate "Test module loading with 'hello world' module"
2520	depends on m
2521	help
2522	  This builds the "test_module" module that emits "Hello, world"
2523	  on printk when loaded. It is designed to be used for basic
2524	  evaluation of the module loading subsystem (for example when
2525	  validating module verification). It lacks any extra dependencies,
2526	  and will not normally be loaded by the system unless explicitly
2527	  requested by name.
2528
2529	  If unsure, say N.
2530
2531config TEST_BITOPS
2532	tristate "Test module for compilation of bitops operations"
2533	help
2534	  This builds the "test_bitops" module that is much like the
2535	  TEST_LKM module except that it does a basic exercise of the
2536	  set/clear_bit macros and get_count_order/long to make sure there are
2537	  no compiler warnings from C=1 sparse checker or -Wextra
2538	  compilations. It has no dependencies and doesn't run or load unless
2539	  explicitly requested by name.  for example: modprobe test_bitops.
2540
2541	  If unsure, say N.
2542
2543config TEST_VMALLOC
2544	tristate "Test module for stress/performance analysis of vmalloc allocator"
2545	default n
2546       depends on MMU
2547	depends on m
2548	help
2549	  This builds the "test_vmalloc" module that should be used for
2550	  stress and performance analysis. So, any new change for vmalloc
2551	  subsystem can be evaluated from performance and stability point
2552	  of view.
2553
2554	  If unsure, say N.
2555
2556config TEST_BPF
2557	tristate "Test BPF filter functionality"
2558	depends on m && NET
2559	help
2560	  This builds the "test_bpf" module that runs various test vectors
2561	  against the BPF interpreter or BPF JIT compiler depending on the
2562	  current setting. This is in particular useful for BPF JIT compiler
2563	  development, but also to run regression tests against changes in
2564	  the interpreter code. It also enables test stubs for eBPF maps and
2565	  verifier used by user space verifier testsuite.
2566
2567	  If unsure, say N.
2568
2569config TEST_BLACKHOLE_DEV
2570	tristate "Test blackhole netdev functionality"
2571	depends on m && NET
2572	help
2573	  This builds the "test_blackhole_dev" module that validates the
2574	  data path through this blackhole netdev.
2575
2576	  If unsure, say N.
2577
2578config FIND_BIT_BENCHMARK
2579	tristate "Test find_bit functions"
2580	help
2581	  This builds the "test_find_bit" module that measure find_*_bit()
2582	  functions performance.
2583
2584	  If unsure, say N.
2585
2586config TEST_FIRMWARE
2587	tristate "Test firmware loading via userspace interface"
2588	depends on FW_LOADER
2589	help
2590	  This builds the "test_firmware" module that creates a userspace
2591	  interface for testing firmware loading. This can be used to
2592	  control the triggering of firmware loading without needing an
2593	  actual firmware-using device. The contents can be rechecked by
2594	  userspace.
2595
2596	  If unsure, say N.
2597
2598config TEST_SYSCTL
2599	tristate "sysctl test driver"
2600	depends on PROC_SYSCTL
2601	help
2602	  This builds the "test_sysctl" module. This driver enables to test the
2603	  proc sysctl interfaces available to drivers safely without affecting
2604	  production knobs which might alter system functionality.
2605
2606	  If unsure, say N.
2607
2608config BITFIELD_KUNIT
2609	tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2610	depends on KUNIT
2611	default KUNIT_ALL_TESTS
2612	help
2613	  Enable this option to test the bitfield functions at boot.
2614
2615	  KUnit tests run during boot and output the results to the debug log
2616	  in TAP format (http://testanything.org/). Only useful for kernel devs
2617	  running the KUnit test harness, and not intended for inclusion into a
2618	  production build.
2619
2620	  For more information on KUnit and unit tests in general please refer
2621	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2622
2623	  If unsure, say N.
2624
2625config CHECKSUM_KUNIT
2626	tristate "KUnit test checksum functions at runtime" if !KUNIT_ALL_TESTS
2627	depends on KUNIT
2628	default KUNIT_ALL_TESTS
2629	help
2630	  Enable this option to test the checksum functions at boot.
2631
2632	  KUnit tests run during boot and output the results to the debug log
2633	  in TAP format (http://testanything.org/). Only useful for kernel devs
2634	  running the KUnit test harness, and not intended for inclusion into a
2635	  production build.
2636
2637	  For more information on KUnit and unit tests in general please refer
2638	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2639
2640	  If unsure, say N.
2641
2642config UTIL_MACROS_KUNIT
2643	tristate "KUnit test util_macros.h functions at runtime" if !KUNIT_ALL_TESTS
2644	depends on KUNIT
2645	default KUNIT_ALL_TESTS
2646	help
2647	  Enable this option to test the util_macros.h function at boot.
2648
2649	  KUnit tests run during boot and output the results to the debug log
2650	  in TAP format (http://testanything.org/). Only useful for kernel devs
2651	  running the KUnit test harness, and not intended for inclusion into a
2652	  production build.
2653
2654	  For more information on KUnit and unit tests in general please refer
2655	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2656
2657	  If unsure, say N.
2658
2659config HASH_KUNIT_TEST
2660	tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2661	depends on KUNIT
2662	default KUNIT_ALL_TESTS
2663	help
2664	  Enable this option to test the kernel's string (<linux/stringhash.h>), and
2665	  integer (<linux/hash.h>) hash functions on boot.
2666
2667	  KUnit tests run during boot and output the results to the debug log
2668	  in TAP format (https://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	  This is intended to help people writing architecture-specific
2676	  optimized versions. If unsure, say N.
2677
2678config RESOURCE_KUNIT_TEST
2679	tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2680	depends on KUNIT
2681	default KUNIT_ALL_TESTS
2682	select GET_FREE_REGION
2683	help
2684	  This builds the resource API unit test.
2685	  Tests the logic of API provided by resource.c and ioport.h.
2686	  For more information on KUnit and unit tests in general please refer
2687	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2688
2689	  If unsure, say N.
2690
2691config SYSCTL_KUNIT_TEST
2692	tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2693	depends on KUNIT
2694	default KUNIT_ALL_TESTS
2695	help
2696	  This builds the proc sysctl unit test, which runs on boot.
2697	  Tests the API contract and implementation correctness of sysctl.
2698	  For more information on KUnit and unit tests in general please refer
2699	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2700
2701	  If unsure, say N.
2702
2703config LIST_KUNIT_TEST
2704	tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2705	depends on KUNIT
2706	default KUNIT_ALL_TESTS
2707	help
2708	  This builds the linked list KUnit test suite.
2709	  It tests that the API and basic functionality of the list_head type
2710	  and associated macros.
2711
2712	  KUnit tests run during boot and output the results to the debug log
2713	  in TAP format (https://testanything.org/). Only useful for kernel devs
2714	  running the KUnit test harness, and not intended for inclusion into a
2715	  production build.
2716
2717	  For more information on KUnit and unit tests in general please refer
2718	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2719
2720	  If unsure, say N.
2721
2722config HASHTABLE_KUNIT_TEST
2723	tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS
2724	depends on KUNIT
2725	default KUNIT_ALL_TESTS
2726	help
2727	  This builds the hashtable KUnit test suite.
2728	  It tests the basic functionality of the API defined in
2729	  include/linux/hashtable.h. For more information on KUnit and
2730	  unit tests in general please refer to the KUnit documentation
2731	  in Documentation/dev-tools/kunit/.
2732
2733	  If unsure, say N.
2734
2735config LINEAR_RANGES_TEST
2736	tristate "KUnit test for linear_ranges"
2737	depends on KUNIT
2738	select LINEAR_RANGES
2739	help
2740	  This builds the linear_ranges unit test, which runs on boot.
2741	  Tests the linear_ranges logic correctness.
2742	  For more information on KUnit and unit tests in general please refer
2743	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2744
2745	  If unsure, say N.
2746
2747config CMDLINE_KUNIT_TEST
2748	tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2749	depends on KUNIT
2750	default KUNIT_ALL_TESTS
2751	help
2752	  This builds the cmdline API unit test.
2753	  Tests the logic of API provided by cmdline.c.
2754	  For more information on KUnit and unit tests in general please refer
2755	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2756
2757	  If unsure, say N.
2758
2759config BITS_TEST
2760	tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2761	depends on KUNIT
2762	default KUNIT_ALL_TESTS
2763	help
2764	  This builds the bits unit test.
2765	  Tests the logic of macros defined in bits.h.
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 SLUB_KUNIT_TEST
2772	tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2773	depends on SLUB_DEBUG && KUNIT
2774	default KUNIT_ALL_TESTS
2775	help
2776	  This builds SLUB allocator unit test.
2777	  Tests SLUB cache debugging functionality.
2778	  For more information on KUnit and unit tests in general please refer
2779	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2780
2781	  If unsure, say N.
2782
2783config RATIONAL_KUNIT_TEST
2784	tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2785	depends on KUNIT && RATIONAL
2786	default KUNIT_ALL_TESTS
2787	help
2788	  This builds the rational math unit test.
2789	  For more information on KUnit and unit tests in general please refer
2790	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2791
2792	  If unsure, say N.
2793
2794config MEMCPY_KUNIT_TEST
2795	tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2796	depends on KUNIT
2797	default KUNIT_ALL_TESTS
2798	help
2799	  Builds unit tests for memcpy(), memmove(), and memset() functions.
2800	  For more information on KUnit and unit tests in general please refer
2801	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2802
2803	  If unsure, say N.
2804
2805config IS_SIGNED_TYPE_KUNIT_TEST
2806	tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2807	depends on KUNIT
2808	default KUNIT_ALL_TESTS
2809	help
2810	  Builds unit tests for the is_signed_type() macro.
2811
2812	  For more information on KUnit and unit tests in general please refer
2813	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2814
2815	  If unsure, say N.
2816
2817config OVERFLOW_KUNIT_TEST
2818	tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2819	depends on KUNIT
2820	default KUNIT_ALL_TESTS
2821	help
2822	  Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2823	  related functions.
2824
2825	  For more information on KUnit and unit tests in general please refer
2826	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2827
2828	  If unsure, say N.
2829
2830config STACKINIT_KUNIT_TEST
2831	tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2832	depends on KUNIT
2833	default KUNIT_ALL_TESTS
2834	help
2835	  Test if the kernel is zero-initializing stack variables and
2836	  padding. Coverage is controlled by compiler flags,
2837	  CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2838	  CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2839	  or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2840
2841config FORTIFY_KUNIT_TEST
2842	tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2843	depends on KUNIT
2844	default KUNIT_ALL_TESTS
2845	help
2846	  Builds unit tests for checking internals of FORTIFY_SOURCE as used
2847	  by the str*() and mem*() family of functions. For testing runtime
2848	  traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2849
2850config HW_BREAKPOINT_KUNIT_TEST
2851	bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2852	depends on HAVE_HW_BREAKPOINT
2853	depends on KUNIT=y
2854	default KUNIT_ALL_TESTS
2855	help
2856	  Tests for hw_breakpoint constraints accounting.
2857
2858	  If unsure, say N.
2859
2860config CRC_KUNIT_TEST
2861	tristate "KUnit tests for CRC functions" if !KUNIT_ALL_TESTS
2862	depends on KUNIT
2863	default KUNIT_ALL_TESTS
2864	select CRC16
2865	select CRC_T10DIF
2866	select CRC32
2867	select CRC64
2868	help
2869	  Unit tests for the CRC library functions.
2870
2871	  This is intended to help people writing architecture-specific
2872	  optimized versions.  If unsure, say N.
2873
2874config CRC_BENCHMARK
2875	bool "Benchmark for the CRC functions"
2876	depends on CRC_KUNIT_TEST
2877	help
2878	  Include benchmarks in the KUnit test suite for the CRC functions.
2879
2880config SIPHASH_KUNIT_TEST
2881	tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2882	depends on KUNIT
2883	default KUNIT_ALL_TESTS
2884	help
2885	  Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2886	  functions on boot (or module load).
2887
2888	  This is intended to help people writing architecture-specific
2889	  optimized versions.  If unsure, say N.
2890
2891config USERCOPY_KUNIT_TEST
2892	tristate "KUnit Test for user/kernel boundary protections"
2893	depends on KUNIT
2894	default KUNIT_ALL_TESTS
2895	help
2896	  This builds the "usercopy_kunit" module that runs sanity checks
2897	  on the copy_to/from_user infrastructure, making sure basic
2898	  user/kernel boundary testing is working.
2899
2900config TEST_UDELAY
2901	tristate "udelay test driver"
2902	help
2903	  This builds the "udelay_test" module that helps to make sure
2904	  that udelay() is working properly.
2905
2906	  If unsure, say N.
2907
2908config TEST_STATIC_KEYS
2909	tristate "Test static keys"
2910	depends on m
2911	help
2912	  Test the static key interfaces.
2913
2914	  If unsure, say N.
2915
2916config TEST_DYNAMIC_DEBUG
2917	tristate "Test DYNAMIC_DEBUG"
2918	depends on DYNAMIC_DEBUG
2919	help
2920	  This module registers a tracer callback to count enabled
2921	  pr_debugs in a 'do_debugging' function, then alters their
2922	  enablements, calls the function, and compares counts.
2923
2924	  If unsure, say N.
2925
2926config TEST_KMOD
2927	tristate "kmod stress tester"
2928	depends on m
2929	depends on NETDEVICES && NET_CORE && INET # for TUN
2930	depends on BLOCK
2931	depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2932	select TEST_LKM
2933	select XFS_FS
2934	select TUN
2935	select BTRFS_FS
2936	help
2937	  Test the kernel's module loading mechanism: kmod. kmod implements
2938	  support to load modules using the Linux kernel's usermode helper.
2939	  This test provides a series of tests against kmod.
2940
2941	  Although technically you can either build test_kmod as a module or
2942	  into the kernel we disallow building it into the kernel since
2943	  it stress tests request_module() and this will very likely cause
2944	  some issues by taking over precious threads available from other
2945	  module load requests, ultimately this could be fatal.
2946
2947	  To run tests run:
2948
2949	  tools/testing/selftests/kmod/kmod.sh --help
2950
2951	  If unsure, say N.
2952
2953config TEST_RUNTIME
2954	bool
2955
2956config TEST_RUNTIME_MODULE
2957	bool
2958
2959config TEST_KALLSYMS
2960	tristate "module kallsyms find_symbol() test"
2961	depends on m
2962	select TEST_RUNTIME
2963	select TEST_RUNTIME_MODULE
2964	select TEST_KALLSYMS_A
2965	select TEST_KALLSYMS_B
2966	select TEST_KALLSYMS_C
2967	select TEST_KALLSYMS_D
2968	help
2969	  This allows us to stress test find_symbol() through the kallsyms
2970	  used to place symbols on the kernel ELF kallsyms and modules kallsyms
2971	  where we place kernel symbols such as exported symbols.
2972
2973	  We have four test modules:
2974
2975	  A: has KALLSYSMS_NUMSYMS exported symbols
2976	  B: uses one of A's symbols
2977	  C: adds KALLSYMS_SCALE_FACTOR * KALLSYSMS_NUMSYMS exported
2978	  D: adds 2 * the symbols than C
2979
2980	  We stress test find_symbol() through two means:
2981
2982	  1) Upon load of B it will trigger simplify_symbols() to look for the
2983	  one symbol it uses from the module A with tons of symbols. This is an
2984	  indirect way for us to have B call resolve_symbol_wait() upon module
2985	  load. This will eventually call find_symbol() which will eventually
2986	  try to find the symbols used with find_exported_symbol_in_section().
2987	  find_exported_symbol_in_section() uses bsearch() so a binary search
2988	  for each symbol. Binary search will at worst be O(log(n)) so the
2989	  larger TEST_MODULE_KALLSYSMS the worse the search.
2990
2991	  2) The selftests should load C first, before B. Upon B's load towards
2992	  the end right before we call module B's init routine we get
2993	  complete_formation() called on the module. That will first check
2994	  for duplicate symbols with the call to verify_exported_symbols().
2995	  That is when we'll force iteration on module C's insane symbol list.
2996	  Since it has 10 * KALLSYMS_NUMSYMS it means we can first test
2997	  just loading B without C. The amount of time it takes to load C Vs
2998	  B can give us an idea of the impact growth of the symbol space and
2999	  give us projection. Module A only uses one symbol from B so to allow
3000	  this scaling in module C to be proportional, if it used more symbols
3001	  then the first test would be doing more and increasing just the
3002	  search space would be slightly different. The last module, module D
3003	  will just increase the search space by twice the number of symbols in
3004	  C so to allow for full projects.
3005
3006	  tools/testing/selftests/module/find_symbol.sh
3007
3008	  The current defaults will incur a build delay of about 7 minutes
3009	  on an x86_64 with only 8 cores. Enable this only if you want to
3010	  stress test find_symbol() with thousands of symbols. At the same
3011	  time this is also useful to test building modules with thousands of
3012	  symbols, and if BTF is enabled this also stress tests adding BTF
3013	  information for each module. Currently enabling many more symbols
3014	  will segfault the build system.
3015
3016	  If unsure, say N.
3017
3018if TEST_KALLSYMS
3019
3020config TEST_KALLSYMS_A
3021	tristate
3022	depends on m
3023
3024config TEST_KALLSYMS_B
3025	tristate
3026	depends on m
3027
3028config TEST_KALLSYMS_C
3029	tristate
3030	depends on m
3031
3032config TEST_KALLSYMS_D
3033	tristate
3034	depends on m
3035
3036choice
3037	prompt "Kallsym test range"
3038	default TEST_KALLSYMS_LARGE
3039	help
3040	  Selecting something other than "Fast" will enable tests which slow
3041	  down the build and may crash your build.
3042
3043config TEST_KALLSYMS_FAST
3044	bool "Fast builds"
3045	help
3046	  You won't really be testing kallsysms, so this just helps fast builds
3047	  when allmodconfig is used..
3048
3049config TEST_KALLSYMS_LARGE
3050	bool "Enable testing kallsyms with large exports"
3051	help
3052	  This will enable larger number of symbols. This will slow down
3053	  your build considerably.
3054
3055config TEST_KALLSYMS_MAX
3056	bool "Known kallsysms limits"
3057	help
3058	  This will enable exports to the point we know we'll start crashing
3059	  builds.
3060
3061endchoice
3062
3063config TEST_KALLSYMS_NUMSYMS
3064	int "test kallsyms number of symbols"
3065	range 2 10000
3066	default 2 if TEST_KALLSYMS_FAST
3067	default 100 if TEST_KALLSYMS_LARGE
3068	default 10000 if TEST_KALLSYMS_MAX
3069	help
3070	  The number of symbols to create on TEST_KALLSYMS_A, only one of which
3071	  module TEST_KALLSYMS_B will use. This also will be used
3072	  for how many symbols TEST_KALLSYMS_C will have, scaled up by
3073	  TEST_KALLSYMS_SCALE_FACTOR. Note that setting this to 10,000 will
3074	  trigger a segfault today, don't use anything close to it unless
3075	  you are aware that this should not be used for automated build tests.
3076
3077config TEST_KALLSYMS_SCALE_FACTOR
3078	int "test kallsyms scale factor"
3079	default 8
3080	help
3081	  How many more unusued symbols will TEST_KALLSYSMS_C have than
3082	  TEST_KALLSYMS_A. If 8, then module C will have 8 * syms
3083	  than module A. Then TEST_KALLSYMS_D will have double the amount
3084	  of symbols than C so to allow projections.
3085
3086endif # TEST_KALLSYMS
3087
3088config TEST_DEBUG_VIRTUAL
3089	tristate "Test CONFIG_DEBUG_VIRTUAL feature"
3090	depends on DEBUG_VIRTUAL
3091	help
3092	  Test the kernel's ability to detect incorrect calls to
3093	  virt_to_phys() done against the non-linear part of the
3094	  kernel's virtual address map.
3095
3096	  If unsure, say N.
3097
3098config TEST_MEMCAT_P
3099	tristate "Test memcat_p() helper function"
3100	help
3101	  Test the memcat_p() helper for correctly merging two
3102	  pointer arrays together.
3103
3104	  If unsure, say N.
3105
3106config TEST_OBJAGG
3107	tristate "Perform selftest on object aggreration manager"
3108	default n
3109	depends on OBJAGG
3110	help
3111	  Enable this option to test object aggregation manager on boot
3112	  (or module load).
3113
3114config TEST_MEMINIT
3115	tristate "Test heap/page initialization"
3116	help
3117	  Test if the kernel is zero-initializing heap and page allocations.
3118	  This can be useful to test init_on_alloc and init_on_free features.
3119
3120	  If unsure, say N.
3121
3122config TEST_HMM
3123	tristate "Test HMM (Heterogeneous Memory Management)"
3124	depends on TRANSPARENT_HUGEPAGE
3125	depends on DEVICE_PRIVATE
3126	select HMM_MIRROR
3127	select MMU_NOTIFIER
3128	help
3129	  This is a pseudo device driver solely for testing HMM.
3130	  Say M here if you want to build the HMM test module.
3131	  Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
3132
3133	  If unsure, say N.
3134
3135config TEST_FREE_PAGES
3136	tristate "Test freeing pages"
3137	help
3138	  Test that a memory leak does not occur due to a race between
3139	  freeing a block of pages and a speculative page reference.
3140	  Loading this module is safe if your kernel has the bug fixed.
3141	  If the bug is not fixed, it will leak gigabytes of memory and
3142	  probably OOM your system.
3143
3144config TEST_FPU
3145	tristate "Test floating point operations in kernel space"
3146	depends on ARCH_HAS_KERNEL_FPU_SUPPORT && !KCOV_INSTRUMENT_ALL
3147	help
3148	  Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
3149	  which will trigger a sequence of floating point operations. This is used
3150	  for self-testing floating point control register setting in
3151	  kernel_fpu_begin().
3152
3153	  If unsure, say N.
3154
3155config TEST_CLOCKSOURCE_WATCHDOG
3156	tristate "Test clocksource watchdog in kernel space"
3157	depends on CLOCKSOURCE_WATCHDOG
3158	help
3159	  Enable this option to create a kernel module that will trigger
3160	  a test of the clocksource watchdog.  This module may be loaded
3161	  via modprobe or insmod in which case it will run upon being
3162	  loaded, or it may be built in, in which case it will run
3163	  shortly after boot.
3164
3165	  If unsure, say N.
3166
3167config TEST_OBJPOOL
3168	tristate "Test module for correctness and stress of objpool"
3169	default n
3170	depends on m && DEBUG_KERNEL
3171	help
3172	  This builds the "test_objpool" module that should be used for
3173	  correctness verification and concurrent testings of objects
3174	  allocation and reclamation.
3175
3176	  If unsure, say N.
3177
3178config INT_POW_TEST
3179	tristate "Integer exponentiation (int_pow) test" if !KUNIT_ALL_TESTS
3180	depends on KUNIT
3181	default KUNIT_ALL_TESTS
3182	help
3183	  This option enables the KUnit test suite for the int_pow function,
3184	  which performs integer exponentiation. The test suite is designed to
3185	  verify that the implementation of int_pow correctly computes the power
3186	  of a given base raised to a given exponent.
3187
3188	  Enabling this option will include tests that check various scenarios
3189	  and edge cases to ensure the accuracy and reliability of the exponentiation
3190	  function.
3191
3192	  If unsure, say N
3193
3194config INT_SQRT_KUNIT_TEST
3195	tristate "Integer square root test" if !KUNIT_ALL_TESTS
3196	depends on KUNIT
3197	default KUNIT_ALL_TESTS
3198	help
3199	  This option enables the KUnit test suite for the int_sqrt() function,
3200	  which performs square root calculation. The test suite checks
3201	  various scenarios, including edge cases, to ensure correctness.
3202
3203	  Enabling this option will include tests that check various scenarios
3204	  and edge cases to ensure the accuracy and reliability of the square root
3205	  function.
3206
3207	  If unsure, say N
3208
3209endif # RUNTIME_TESTING_MENU
3210
3211config ARCH_USE_MEMTEST
3212	bool
3213	help
3214	  An architecture should select this when it uses early_memtest()
3215	  during boot process.
3216
3217config MEMTEST
3218	bool "Memtest"
3219	depends on ARCH_USE_MEMTEST
3220	help
3221	  This option adds a kernel parameter 'memtest', which allows memtest
3222	  to be set and executed.
3223	        memtest=0, mean disabled; -- default
3224	        memtest=1, mean do 1 test pattern;
3225	        ...
3226	        memtest=17, mean do 17 test patterns.
3227	  If you are unsure how to answer this question, answer N.
3228
3229
3230
3231config HYPERV_TESTING
3232	bool "Microsoft Hyper-V driver testing"
3233	default n
3234	depends on HYPERV && DEBUG_FS
3235	help
3236	  Select this option to enable Hyper-V vmbus testing.
3237
3238endmenu # "Kernel Testing and Coverage"
3239
3240menu "Rust hacking"
3241
3242config RUST_DEBUG_ASSERTIONS
3243	bool "Debug assertions"
3244	depends on RUST
3245	help
3246	  Enables rustc's `-Cdebug-assertions` codegen option.
3247
3248	  This flag lets you turn `cfg(debug_assertions)` conditional
3249	  compilation on or off. This can be used to enable extra debugging
3250	  code in development but not in production. For example, it controls
3251	  the behavior of the standard library's `debug_assert!` macro.
3252
3253	  Note that this will apply to all Rust code, including `core`.
3254
3255	  If unsure, say N.
3256
3257config RUST_OVERFLOW_CHECKS
3258	bool "Overflow checks"
3259	default y
3260	depends on RUST
3261	help
3262	  Enables rustc's `-Coverflow-checks` codegen option.
3263
3264	  This flag allows you to control the behavior of runtime integer
3265	  overflow. When overflow-checks are enabled, a Rust panic will occur
3266	  on overflow.
3267
3268	  Note that this will apply to all Rust code, including `core`.
3269
3270	  If unsure, say Y.
3271
3272config RUST_BUILD_ASSERT_ALLOW
3273	bool "Allow unoptimized build-time assertions"
3274	depends on RUST
3275	help
3276	  Controls how `build_error!` and `build_assert!` are handled during the build.
3277
3278	  If calls to them exist in the binary, it may indicate a violated invariant
3279	  or that the optimizer failed to verify the invariant during compilation.
3280
3281	  This should not happen, thus by default the build is aborted. However,
3282	  as an escape hatch, you can choose Y here to ignore them during build
3283	  and let the check be carried at runtime (with `panic!` being called if
3284	  the check fails).
3285
3286	  If unsure, say N.
3287
3288config RUST_KERNEL_DOCTESTS
3289	bool "Doctests for the `kernel` crate" if !KUNIT_ALL_TESTS
3290	depends on RUST && KUNIT=y
3291	default KUNIT_ALL_TESTS
3292	help
3293	  This builds the documentation tests of the `kernel` crate
3294	  as KUnit tests.
3295
3296	  For more information on KUnit and unit tests in general,
3297	  please refer to the KUnit documentation in Documentation/dev-tools/kunit/.
3298
3299	  If unsure, say N.
3300
3301endmenu # "Rust"
3302
3303endmenu # Kernel hacking
3304