xref: /linux-6.15/lib/Kconfig.debug (revision 13c23cb4)
1# SPDX-License-Identifier: GPL-2.0-only
2menu "Kernel hacking"
3
4menu "printk and dmesg options"
5
6config PRINTK_TIME
7	bool "Show timing information on printks"
8	depends on PRINTK
9	help
10	  Selecting this option causes time stamps of the printk()
11	  messages to be added to the output of the syslog() system
12	  call and at the console.
13
14	  The timestamp is always recorded internally, and exported
15	  to /dev/kmsg. This flag just specifies if the timestamp should
16	  be included, not that the timestamp is recorded.
17
18	  The behavior is also controlled by the kernel command line
19	  parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
20
21config PRINTK_CALLER
22	bool "Show caller information on printks"
23	depends on PRINTK
24	help
25	  Selecting this option causes printk() to add a caller "thread id" (if
26	  in task context) or a caller "processor id" (if not in task context)
27	  to every message.
28
29	  This option is intended for environments where multiple threads
30	  concurrently call printk() for many times, for it is difficult to
31	  interpret without knowing where these lines (or sometimes individual
32	  line which was divided into multiple lines due to race) came from.
33
34	  Since toggling after boot makes the code racy, currently there is
35	  no option to enable/disable at the kernel command line parameter or
36	  sysfs interface.
37
38config STACKTRACE_BUILD_ID
39	bool "Show build ID information in stacktraces"
40	depends on PRINTK
41	help
42	  Selecting this option adds build ID information for symbols in
43	  stacktraces printed with the printk format '%p[SR]b'.
44
45	  This option is intended for distros where debuginfo is not easily
46	  accessible but can be downloaded given the build ID of the vmlinux or
47	  kernel module where the function is located.
48
49config CONSOLE_LOGLEVEL_DEFAULT
50	int "Default console loglevel (1-15)"
51	range 1 15
52	default "7"
53	help
54	  Default loglevel to determine what will be printed on the console.
55
56	  Setting a default here is equivalent to passing in loglevel=<x> in
57	  the kernel bootargs. loglevel=<x> continues to override whatever
58	  value is specified here as well.
59
60	  Note: This does not affect the log level of un-prefixed printk()
61	  usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
62	  option.
63
64config CONSOLE_LOGLEVEL_QUIET
65	int "quiet console loglevel (1-15)"
66	range 1 15
67	default "4"
68	help
69	  loglevel to use when "quiet" is passed on the kernel commandline.
70
71	  When "quiet" is passed on the kernel commandline this loglevel
72	  will be used as the loglevel. IOW passing "quiet" will be the
73	  equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
74
75config MESSAGE_LOGLEVEL_DEFAULT
76	int "Default message log level (1-7)"
77	range 1 7
78	default "4"
79	help
80	  Default log level for printk statements with no specified priority.
81
82	  This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
83	  that are auditing their logs closely may want to set it to a lower
84	  priority.
85
86	  Note: This does not affect what message level gets printed on the console
87	  by default. To change that, use loglevel=<x> in the kernel bootargs,
88	  or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
89
90config BOOT_PRINTK_DELAY
91	bool "Delay each boot printk message by N milliseconds"
92	depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
93	help
94	  This build option allows you to read kernel boot messages
95	  by inserting a short delay after each one.  The delay is
96	  specified in milliseconds on the kernel command line,
97	  using "boot_delay=N".
98
99	  It is likely that you would also need to use "lpj=M" to preset
100	  the "loops per jiffy" value.
101	  See a previous boot log for the "lpj" value to use for your
102	  system, and then set "lpj=M" before setting "boot_delay=N".
103	  NOTE:  Using this option may adversely affect SMP systems.
104	  I.e., processors other than the first one may not boot up.
105	  BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
106	  what it believes to be lockup conditions.
107
108config DYNAMIC_DEBUG
109	bool "Enable dynamic printk() support"
110	default n
111	depends on PRINTK
112	depends on (DEBUG_FS || PROC_FS)
113	select DYNAMIC_DEBUG_CORE
114	help
115
116	  Compiles debug level messages into the kernel, which would not
117	  otherwise be available at runtime. These messages can then be
118	  enabled/disabled based on various levels of scope - per source file,
119	  function, module, format string, and line number. This mechanism
120	  implicitly compiles in all pr_debug() and dev_dbg() calls, which
121	  enlarges the kernel text size by about 2%.
122
123	  If a source file is compiled with DEBUG flag set, any
124	  pr_debug() calls in it are enabled by default, but can be
125	  disabled at runtime as below.  Note that DEBUG flag is
126	  turned on by many CONFIG_*DEBUG* options.
127
128	  Usage:
129
130	  Dynamic debugging is controlled via the 'dynamic_debug/control' file,
131	  which is contained in the 'debugfs' filesystem or procfs.
132	  Thus, the debugfs or procfs filesystem must first be mounted before
133	  making use of this feature.
134	  We refer the control file as: <debugfs>/dynamic_debug/control. This
135	  file contains a list of the debug statements that can be enabled. The
136	  format for each line of the file is:
137
138		filename:lineno [module]function flags format
139
140	  filename : source file of the debug statement
141	  lineno : line number of the debug statement
142	  module : module that contains the debug statement
143	  function : function that contains the debug statement
144	  flags : '=p' means the line is turned 'on' for printing
145	  format : the format used for the debug statement
146
147	  From a live system:
148
149		nullarbor:~ # cat <debugfs>/dynamic_debug/control
150		# filename:lineno [module]function flags format
151		fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
152		fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
153		fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
154
155	  Example usage:
156
157		// enable the message at line 1603 of file svcsock.c
158		nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
159						<debugfs>/dynamic_debug/control
160
161		// enable all the messages in file svcsock.c
162		nullarbor:~ # echo -n 'file svcsock.c +p' >
163						<debugfs>/dynamic_debug/control
164
165		// enable all the messages in the NFS server module
166		nullarbor:~ # echo -n 'module nfsd +p' >
167						<debugfs>/dynamic_debug/control
168
169		// enable all 12 messages in the function svc_process()
170		nullarbor:~ # echo -n 'func svc_process +p' >
171						<debugfs>/dynamic_debug/control
172
173		// disable all 12 messages in the function svc_process()
174		nullarbor:~ # echo -n 'func svc_process -p' >
175						<debugfs>/dynamic_debug/control
176
177	  See Documentation/admin-guide/dynamic-debug-howto.rst for additional
178	  information.
179
180config DYNAMIC_DEBUG_CORE
181	bool "Enable core function of dynamic debug support"
182	depends on PRINTK
183	depends on (DEBUG_FS || PROC_FS)
184	help
185	  Enable core functional support of dynamic debug. It is useful
186	  when you want to tie dynamic debug to your kernel modules with
187	  DYNAMIC_DEBUG_MODULE defined for each of them, especially for
188	  the case of embedded system where the kernel image size is
189	  sensitive for people.
190
191config SYMBOLIC_ERRNAME
192	bool "Support symbolic error names in printf"
193	default y if PRINTK
194	help
195	  If you say Y here, the kernel's printf implementation will
196	  be able to print symbolic error names such as ENOSPC instead
197	  of the number 28. It makes the kernel image slightly larger
198	  (about 3KB), but can make the kernel logs easier to read.
199
200config DEBUG_BUGVERBOSE
201	bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
202	depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
203	default y
204	help
205	  Say Y here to make BUG() panics output the file name and line number
206	  of the BUG call as well as the EIP and oops trace.  This aids
207	  debugging but costs about 70-100K of memory.
208
209endmenu # "printk and dmesg options"
210
211config DEBUG_KERNEL
212	bool "Kernel debugging"
213	help
214	  Say Y here if you are developing drivers or trying to debug and
215	  identify kernel problems.
216
217config DEBUG_MISC
218	bool "Miscellaneous debug code"
219	default DEBUG_KERNEL
220	depends on DEBUG_KERNEL
221	help
222	  Say Y here if you need to enable miscellaneous debug code that should
223	  be under a more specific debug option but isn't.
224
225menu "Compile-time checks and compiler options"
226
227config DEBUG_INFO
228	bool
229	help
230	  A kernel debug info option other than "None" has been selected
231	  in the "Debug information" choice below, indicating that debug
232	  information will be generated for build targets.
233
234# Clang generates .uleb128 with label differences for DWARF v5, a feature that
235# older binutils ports do not support when utilizing RISC-V style linker
236# relaxation: https://sourceware.org/bugzilla/show_bug.cgi?id=27215
237config AS_HAS_NON_CONST_ULEB128
238	def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:)
239
240choice
241	prompt "Debug information"
242	depends on DEBUG_KERNEL
243	help
244	  Selecting something other than "None" results in a kernel image
245	  that will include debugging info resulting in a larger kernel image.
246	  This adds debug symbols to the kernel and modules (gcc -g), and
247	  is needed if you intend to use kernel crashdump or binary object
248	  tools like crash, kgdb, LKCD, gdb, etc on the kernel.
249
250	  Choose which version of DWARF debug info to emit. If unsure,
251	  select "Toolchain default".
252
253config DEBUG_INFO_NONE
254	bool "Disable debug information"
255	help
256	  Do not build the kernel with debugging information, which will
257	  result in a faster and smaller build.
258
259config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
260	bool "Rely on the toolchain's implicit default DWARF version"
261	select DEBUG_INFO
262	depends on !CC_IS_CLANG || AS_IS_LLVM || CLANG_VERSION < 140000 || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128)
263	help
264	  The implicit default version of DWARF debug info produced by a
265	  toolchain changes over time.
266
267	  This can break consumers of the debug info that haven't upgraded to
268	  support newer revisions, and prevent testing newer versions, but
269	  those should be less common scenarios.
270
271config DEBUG_INFO_DWARF4
272	bool "Generate DWARF Version 4 debuginfo"
273	select DEBUG_INFO
274	depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)
275	help
276	  Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2
277	  if using clang without clang's integrated assembler, and gdb 7.0+.
278
279	  If you have consumers of DWARF debug info that are not ready for
280	  newer revisions of DWARF, you may wish to choose this or have your
281	  config select this.
282
283config DEBUG_INFO_DWARF5
284	bool "Generate DWARF Version 5 debuginfo"
285	select DEBUG_INFO
286	depends on !ARCH_HAS_BROKEN_DWARF5
287	depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128)
288	help
289	  Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
290	  5.0+ accepts the -gdwarf-5 flag but only had partial support for some
291	  draft features until 7.0), and gdb 8.0+.
292
293	  Changes to the structure of debug info in Version 5 allow for around
294	  15-18% savings in resulting image and debug info section sizes as
295	  compared to DWARF Version 4. DWARF Version 5 standardizes previous
296	  extensions such as accelerators for symbol indexing and the format
297	  for fission (.dwo/.dwp) files. Users may not want to select this
298	  config if they rely on tooling that has not yet been updated to
299	  support DWARF Version 5.
300
301endchoice # "Debug information"
302
303if DEBUG_INFO
304
305config DEBUG_INFO_REDUCED
306	bool "Reduce debugging information"
307	help
308	  If you say Y here gcc is instructed to generate less debugging
309	  information for structure types. This means that tools that
310	  need full debugging information (like kgdb or systemtap) won't
311	  be happy. But if you merely need debugging information to
312	  resolve line numbers there is no loss. Advantage is that
313	  build directory object sizes shrink dramatically over a full
314	  DEBUG_INFO build and compile times are reduced too.
315	  Only works with newer gcc versions.
316
317choice
318	prompt "Compressed Debug information"
319	help
320	  Compress the resulting debug info. Results in smaller debug info sections,
321	  but requires that consumers are able to decompress the results.
322
323	  If unsure, choose DEBUG_INFO_COMPRESSED_NONE.
324
325config DEBUG_INFO_COMPRESSED_NONE
326	bool "Don't compress debug information"
327	help
328	  Don't compress debug info sections.
329
330config DEBUG_INFO_COMPRESSED_ZLIB
331	bool "Compress debugging information with zlib"
332	depends on $(cc-option,-gz=zlib)
333	depends on $(ld-option,--compress-debug-sections=zlib)
334	help
335	  Compress the debug information using zlib.  Requires GCC 5.0+ or Clang
336	  5.0+, binutils 2.26+, and zlib.
337
338	  Users of dpkg-deb via scripts/package/builddeb may find an increase in
339	  size of their debug .deb packages with this config set, due to the
340	  debug info being compressed with zlib, then the object files being
341	  recompressed with a different compression scheme. But this is still
342	  preferable to setting $KDEB_COMPRESS to "none" which would be even
343	  larger.
344
345config DEBUG_INFO_COMPRESSED_ZSTD
346	bool "Compress debugging information with zstd"
347	depends on $(cc-option,-gz=zstd)
348	depends on $(ld-option,--compress-debug-sections=zstd)
349	help
350	  Compress the debug information using zstd.  This may provide better
351	  compression than zlib, for about the same time costs, but requires newer
352	  toolchain support.  Requires GCC 13.0+ or Clang 16.0+, binutils 2.40+, and
353	  zstd.
354
355endchoice # "Compressed Debug information"
356
357config DEBUG_INFO_SPLIT
358	bool "Produce split debuginfo in .dwo files"
359	depends on $(cc-option,-gsplit-dwarf)
360	# RISC-V linker relaxation + -gsplit-dwarf has issues with LLVM and GCC
361	# prior to 12.x:
362	# https://github.com/llvm/llvm-project/issues/56642
363	# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99090
364	depends on !RISCV || GCC_VERSION >= 120000
365	help
366	  Generate debug info into separate .dwo files. This significantly
367	  reduces the build directory size for builds with DEBUG_INFO,
368	  because it stores the information only once on disk in .dwo
369	  files instead of multiple times in object files and executables.
370	  In addition the debug information is also compressed.
371
372	  Requires recent gcc (4.7+) and recent gdb/binutils.
373	  Any tool that packages or reads debug information would need
374	  to know about the .dwo files and include them.
375	  Incompatible with older versions of ccache.
376
377config DEBUG_INFO_BTF
378	bool "Generate BTF type information"
379	depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
380	depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
381	depends on BPF_SYSCALL
382	depends on PAHOLE_VERSION >= 116
383	depends on DEBUG_INFO_DWARF4 || PAHOLE_VERSION >= 121
384	# pahole uses elfutils, which does not have support for Hexagon relocations
385	depends on !HEXAGON
386	help
387	  Generate deduplicated BTF type information from DWARF debug info.
388	  Turning this on requires pahole v1.16 or later (v1.21 or later to
389	  support DWARF 5), which will convert DWARF type info into equivalent
390	  deduplicated BTF type info.
391
392config PAHOLE_HAS_SPLIT_BTF
393	def_bool PAHOLE_VERSION >= 119
394
395config PAHOLE_HAS_BTF_TAG
396	def_bool PAHOLE_VERSION >= 123
397	depends on CC_IS_CLANG
398	help
399	  Decide whether pahole emits btf_tag attributes (btf_type_tag and
400	  btf_decl_tag) or not. Currently only clang compiler implements
401	  these attributes, so make the config depend on CC_IS_CLANG.
402
403config PAHOLE_HAS_LANG_EXCLUDE
404	def_bool PAHOLE_VERSION >= 124
405	help
406	  Support for the --lang_exclude flag which makes pahole exclude
407	  compilation units from the supplied language. Used in Kbuild to
408	  omit Rust CUs which are not supported in version 1.24 of pahole,
409	  otherwise it would emit malformed kernel and module binaries when
410	  using DEBUG_INFO_BTF_MODULES.
411
412config DEBUG_INFO_BTF_MODULES
413	bool "Generate BTF type information for kernel modules"
414	default y
415	depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
416	help
417	  Generate compact split BTF type information for kernel modules.
418
419config MODULE_ALLOW_BTF_MISMATCH
420	bool "Allow loading modules with non-matching BTF type info"
421	depends on DEBUG_INFO_BTF_MODULES
422	help
423	  For modules whose split BTF does not match vmlinux, load without
424	  BTF rather than refusing to load. The default behavior with
425	  module BTF enabled is to reject modules with such mismatches;
426	  this option will still load module BTF where possible but ignore
427	  it when a mismatch is found.
428
429config GDB_SCRIPTS
430	bool "Provide GDB scripts for kernel debugging"
431	help
432	  This creates the required links to GDB helper scripts in the
433	  build directory. If you load vmlinux into gdb, the helper
434	  scripts will be automatically imported by gdb as well, and
435	  additional functions are available to analyze a Linux kernel
436	  instance. See Documentation/process/debugging/gdb-kernel-debugging.rst
437	  for further details.
438
439endif # DEBUG_INFO
440
441config FRAME_WARN
442	int "Warn for stack frames larger than"
443	range 0 8192
444	default 0 if KMSAN
445	default 2048 if GCC_PLUGIN_LATENT_ENTROPY
446	default 2048 if PARISC
447	default 1536 if (!64BIT && XTENSA)
448	default 1280 if KASAN && !64BIT
449	default 1024 if !64BIT
450	default 2048 if 64BIT
451	help
452	  Tell the compiler to warn at build time for stack frames larger than this.
453	  Setting this too low will cause a lot of warnings.
454	  Setting it to 0 disables the warning.
455
456config STRIP_ASM_SYMS
457	bool "Strip assembler-generated symbols during link"
458	default n
459	help
460	  Strip internal assembler-generated symbols during a link (symbols
461	  that look like '.Lxxx') so they don't pollute the output of
462	  get_wchan() and suchlike.
463
464config READABLE_ASM
465	bool "Generate readable assembler code"
466	depends on DEBUG_KERNEL
467	depends on CC_IS_GCC
468	help
469	  Disable some compiler optimizations that tend to generate human unreadable
470	  assembler output. This may make the kernel slightly slower, but it helps
471	  to keep kernel developers who have to stare a lot at assembler listings
472	  sane.
473
474config HEADERS_INSTALL
475	bool "Install uapi headers to usr/include"
476	depends on !UML
477	help
478	  This option will install uapi headers (headers exported to user-space)
479	  into the usr/include directory for use during the kernel build.
480	  This is unneeded for building the kernel itself, but needed for some
481	  user-space program samples. It is also needed by some features such
482	  as uapi header sanity checks.
483
484config DEBUG_SECTION_MISMATCH
485	bool "Enable full Section mismatch analysis"
486	depends on CC_IS_GCC
487	help
488	  The section mismatch analysis checks if there are illegal
489	  references from one section to another section.
490	  During linktime or runtime, some sections are dropped;
491	  any use of code/data previously in these sections would
492	  most likely result in an oops.
493	  In the code, functions and variables are annotated with
494	  __init,, etc. (see the full list in include/linux/init.h),
495	  which results in the code/data being placed in specific sections.
496	  The section mismatch analysis is always performed after a full
497	  kernel build, and enabling this option causes the following
498	  additional step to occur:
499	  - Add the option -fno-inline-functions-called-once to gcc commands.
500	    When inlining a function annotated with __init in a non-init
501	    function, we would lose the section information and thus
502	    the analysis would not catch the illegal reference.
503	    This option tells gcc to inline less (but it does result in
504	    a larger kernel).
505
506config SECTION_MISMATCH_WARN_ONLY
507	bool "Make section mismatch errors non-fatal"
508	default y
509	help
510	  If you say N here, the build process will fail if there are any
511	  section mismatch, instead of just throwing warnings.
512
513	  If unsure, say Y.
514
515config DEBUG_FORCE_FUNCTION_ALIGN_64B
516	bool "Force all function address 64B aligned"
517	depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC || RISCV || S390)
518	select FUNCTION_ALIGNMENT_64B
519	help
520	  There are cases that a commit from one domain changes the function
521	  address alignment of other domains, and cause magic performance
522	  bump (regression or improvement). Enable this option will help to
523	  verify if the bump is caused by function alignment changes, while
524	  it will slightly increase the kernel size and affect icache usage.
525
526	  It is mainly for debug and performance tuning use.
527
528#
529# Select this config option from the architecture Kconfig, if it
530# is preferred to always offer frame pointers as a config
531# option on the architecture (regardless of KERNEL_DEBUG):
532#
533config ARCH_WANT_FRAME_POINTERS
534	bool
535
536config FRAME_POINTER
537	bool "Compile the kernel with frame pointers"
538	depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
539	default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
540	help
541	  If you say Y here the resulting kernel image will be slightly
542	  larger and slower, but it gives very useful debugging information
543	  in case of kernel bugs. (precise oopses/stacktraces/warnings)
544
545config OBJTOOL
546	bool
547
548config OBJTOOL_WERROR
549	bool "Upgrade objtool warnings to errors"
550	depends on OBJTOOL && !COMPILE_TEST
551	help
552	  Fail the build on objtool warnings.
553
554	  Objtool warnings can indicate kernel instability, including boot
555	  failures.  This option is highly recommended.
556
557	  If unsure, say Y.
558
559config STACK_VALIDATION
560	bool "Compile-time stack metadata validation"
561	depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
562	select OBJTOOL
563	default n
564	help
565	  Validate frame pointer rules at compile-time.  This helps ensure that
566	  runtime stack traces are more reliable.
567
568	  For more information, see
569	  tools/objtool/Documentation/objtool.txt.
570
571config NOINSTR_VALIDATION
572	bool
573	depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
574	select OBJTOOL
575	default y
576
577config VMLINUX_MAP
578	bool "Generate vmlinux.map file when linking"
579	depends on EXPERT
580	help
581	  Selecting this option will pass "-Map=vmlinux.map" to ld
582	  when linking vmlinux. That file can be useful for verifying
583	  and debugging magic section games, and for seeing which
584	  pieces of code get eliminated with
585	  CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
586
587config BUILTIN_MODULE_RANGES
588	bool "Generate address range information for builtin modules"
589	depends on !LTO
590	depends on VMLINUX_MAP
591	help
592	 When modules are built into the kernel, there will be no module name
593	 associated with its symbols in /proc/kallsyms.  Tracers may want to
594	 identify symbols by module name and symbol name regardless of whether
595	 the module is configured as loadable or not.
596
597	 This option generates modules.builtin.ranges in the build tree with
598	 offset ranges (per ELF section) for the module(s) they belong to.
599	 It also records an anchor symbol to determine the load address of the
600	 section.
601
602config DEBUG_FORCE_WEAK_PER_CPU
603	bool "Force weak per-cpu definitions"
604	depends on DEBUG_KERNEL
605	help
606	  s390 and alpha require percpu variables in modules to be
607	  defined weak to work around addressing range issue which
608	  puts the following two restrictions on percpu variable
609	  definitions.
610
611	  1. percpu symbols must be unique whether static or not
612	  2. percpu variables can't be defined inside a function
613
614	  To ensure that generic code follows the above rules, this
615	  option forces all percpu variables to be defined as weak.
616
617endmenu # "Compiler options"
618
619menu "Generic Kernel Debugging Instruments"
620
621config MAGIC_SYSRQ
622	bool "Magic SysRq key"
623	depends on !UML
624	help
625	  If you say Y here, you will have some control over the system even
626	  if the system crashes for example during kernel debugging (e.g., you
627	  will be able to flush the buffer cache to disk, reboot the system
628	  immediately or dump some status information). This is accomplished
629	  by pressing various keys while holding SysRq (Alt+PrintScreen). It
630	  also works on a serial console (on PC hardware at least), if you
631	  send a BREAK and then within 5 seconds a command keypress. The
632	  keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
633	  Don't say Y unless you really know what this hack does.
634
635config MAGIC_SYSRQ_DEFAULT_ENABLE
636	hex "Enable magic SysRq key functions by default"
637	depends on MAGIC_SYSRQ
638	default 0x1
639	help
640	  Specifies which SysRq key functions are enabled by default.
641	  This may be set to 1 or 0 to enable or disable them all, or
642	  to a bitmask as described in Documentation/admin-guide/sysrq.rst.
643
644config MAGIC_SYSRQ_SERIAL
645	bool "Enable magic SysRq key over serial"
646	depends on MAGIC_SYSRQ
647	default y
648	help
649	  Many embedded boards have a disconnected TTL level serial which can
650	  generate some garbage that can lead to spurious false sysrq detects.
651	  This option allows you to decide whether you want to enable the
652	  magic SysRq key.
653
654config MAGIC_SYSRQ_SERIAL_SEQUENCE
655	string "Char sequence that enables magic SysRq over serial"
656	depends on MAGIC_SYSRQ_SERIAL
657	default ""
658	help
659	  Specifies a sequence of characters that can follow BREAK to enable
660	  SysRq on a serial console.
661
662	  If unsure, leave an empty string and the option will not be enabled.
663
664config DEBUG_FS
665	bool "Debug Filesystem"
666	help
667	  debugfs is a virtual file system that kernel developers use to put
668	  debugging files into.  Enable this option to be able to read and
669	  write to these files.
670
671	  For detailed documentation on the debugfs API, see
672	  Documentation/filesystems/.
673
674	  If unsure, say N.
675
676choice
677	prompt "Debugfs default access"
678	depends on DEBUG_FS
679	default DEBUG_FS_ALLOW_ALL
680	help
681	  This selects the default access restrictions for debugfs.
682	  It can be overridden with kernel command line option
683	  debugfs=[on,no-mount,off]. The restrictions apply for API access
684	  and filesystem registration.
685
686config DEBUG_FS_ALLOW_ALL
687	bool "Access normal"
688	help
689	  No restrictions apply. Both API and filesystem registration
690	  is on. This is the normal default operation.
691
692config DEBUG_FS_DISALLOW_MOUNT
693	bool "Do not register debugfs as filesystem"
694	help
695	  The API is open but filesystem is not loaded. Clients can still do
696	  their work and read with debug tools that do not need
697	  debugfs filesystem.
698
699config DEBUG_FS_ALLOW_NONE
700	bool "No access"
701	help
702	  Access is off. Clients get -PERM when trying to create nodes in
703	  debugfs tree and debugfs is not registered as a filesystem.
704	  Client can then back-off or continue without debugfs access.
705
706endchoice
707
708source "lib/Kconfig.kgdb"
709source "lib/Kconfig.ubsan"
710source "lib/Kconfig.kcsan"
711
712endmenu
713
714menu "Networking Debugging"
715
716source "net/Kconfig.debug"
717
718endmenu # "Networking Debugging"
719
720menu "Memory Debugging"
721
722source "mm/Kconfig.debug"
723
724config DEBUG_OBJECTS
725	bool "Debug object operations"
726	depends on DEBUG_KERNEL
727	help
728	  If you say Y here, additional code will be inserted into the
729	  kernel to track the life time of various objects and validate
730	  the operations on those objects.
731
732config DEBUG_OBJECTS_SELFTEST
733	bool "Debug objects selftest"
734	depends on DEBUG_OBJECTS
735	help
736	  This enables the selftest of the object debug code.
737
738config DEBUG_OBJECTS_FREE
739	bool "Debug objects in freed memory"
740	depends on DEBUG_OBJECTS
741	help
742	  This enables checks whether a k/v free operation frees an area
743	  which contains an object which has not been deactivated
744	  properly. This can make kmalloc/kfree-intensive workloads
745	  much slower.
746
747config DEBUG_OBJECTS_TIMERS
748	bool "Debug timer objects"
749	depends on DEBUG_OBJECTS
750	help
751	  If you say Y here, additional code will be inserted into the
752	  timer routines to track the life time of timer objects and
753	  validate the timer operations.
754
755config DEBUG_OBJECTS_WORK
756	bool "Debug work objects"
757	depends on DEBUG_OBJECTS
758	help
759	  If you say Y here, additional code will be inserted into the
760	  work queue routines to track the life time of work objects and
761	  validate the work operations.
762
763config DEBUG_OBJECTS_RCU_HEAD
764	bool "Debug RCU callbacks objects"
765	depends on DEBUG_OBJECTS
766	help
767	  Enable this to turn on debugging of RCU list heads (call_rcu() usage).
768
769config DEBUG_OBJECTS_PERCPU_COUNTER
770	bool "Debug percpu counter objects"
771	depends on DEBUG_OBJECTS
772	help
773	  If you say Y here, additional code will be inserted into the
774	  percpu counter routines to track the life time of percpu counter
775	  objects and validate the percpu counter operations.
776
777config DEBUG_OBJECTS_ENABLE_DEFAULT
778	int "debug_objects bootup default value (0-1)"
779	range 0 1
780	default "1"
781	depends on DEBUG_OBJECTS
782	help
783	  Debug objects boot parameter default value
784
785config SHRINKER_DEBUG
786	bool "Enable shrinker debugging support"
787	depends on DEBUG_FS
788	help
789	  Say Y to enable the shrinker debugfs interface which provides
790	  visibility into the kernel memory shrinkers subsystem.
791	  Disable it to avoid an extra memory footprint.
792
793config DEBUG_STACK_USAGE
794	bool "Stack utilization instrumentation"
795	depends on DEBUG_KERNEL
796	help
797	  Enables the display of the minimum amount of free stack which each
798	  task has ever had available in the sysrq-T and sysrq-P debug output.
799	  Also emits a message to dmesg when a process exits if that process
800	  used more stack space than previously exiting processes.
801
802	  This option will slow down process creation somewhat.
803
804config SCHED_STACK_END_CHECK
805	bool "Detect stack corruption on calls to schedule()"
806	depends on DEBUG_KERNEL
807	default n
808	help
809	  This option checks for a stack overrun on calls to schedule().
810	  If the stack end location is found to be over written always panic as
811	  the content of the corrupted region can no longer be trusted.
812	  This is to ensure no erroneous behaviour occurs which could result in
813	  data corruption or a sporadic crash at a later stage once the region
814	  is examined. The runtime overhead introduced is minimal.
815
816config ARCH_HAS_DEBUG_VM_PGTABLE
817	bool
818	help
819	  An architecture should select this when it can successfully
820	  build and run DEBUG_VM_PGTABLE.
821
822config DEBUG_VM_IRQSOFF
823	def_bool DEBUG_VM && !PREEMPT_RT
824
825config DEBUG_VM
826	bool "Debug VM"
827	depends on DEBUG_KERNEL
828	help
829	  Enable this to turn on extended checks in the virtual-memory system
830	  that may impact performance.
831
832	  If unsure, say N.
833
834config DEBUG_VM_SHOOT_LAZIES
835	bool "Debug MMU_LAZY_TLB_SHOOTDOWN implementation"
836	depends on DEBUG_VM
837	depends on MMU_LAZY_TLB_SHOOTDOWN
838	help
839	  Enable additional IPIs that ensure lazy tlb mm references are removed
840	  before the mm is freed.
841
842	  If unsure, say N.
843
844config DEBUG_VM_MAPLE_TREE
845	bool "Debug VM maple trees"
846	depends on DEBUG_VM
847	select DEBUG_MAPLE_TREE
848	help
849	  Enable VM maple tree debugging information and extra validations.
850
851	  If unsure, say N.
852
853config DEBUG_VM_RB
854	bool "Debug VM red-black trees"
855	depends on DEBUG_VM
856	help
857	  Enable VM red-black tree debugging information and extra validations.
858
859	  If unsure, say N.
860
861config DEBUG_VM_PGFLAGS
862	bool "Debug page-flags operations"
863	depends on DEBUG_VM
864	help
865	  Enables extra validation on page flags operations.
866
867	  If unsure, say N.
868
869config DEBUG_VM_PGTABLE
870	bool "Debug arch page table for semantics compliance"
871	depends on MMU
872	depends on ARCH_HAS_DEBUG_VM_PGTABLE
873	default y if DEBUG_VM
874	help
875	  This option provides a debug method which can be used to test
876	  architecture page table helper functions on various platforms in
877	  verifying if they comply with expected generic MM semantics. This
878	  will help architecture code in making sure that any changes or
879	  new additions of these helpers still conform to expected
880	  semantics of the generic MM. Platforms will have to opt in for
881	  this through ARCH_HAS_DEBUG_VM_PGTABLE.
882
883	  If unsure, say N.
884
885config ARCH_HAS_DEBUG_VIRTUAL
886	bool
887
888config DEBUG_VIRTUAL
889	bool "Debug VM translations"
890	depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
891	help
892	  Enable some costly sanity checks in virtual to page code. This can
893	  catch mistakes with virt_to_page() and friends.
894
895	  If unsure, say N.
896
897config DEBUG_NOMMU_REGIONS
898	bool "Debug the global anon/private NOMMU mapping region tree"
899	depends on DEBUG_KERNEL && !MMU
900	help
901	  This option causes the global tree of anonymous and private mapping
902	  regions to be regularly checked for invalid topology.
903
904config DEBUG_MEMORY_INIT
905	bool "Debug memory initialisation" if EXPERT
906	default !EXPERT
907	help
908	  Enable this for additional checks during memory initialisation.
909	  The sanity checks verify aspects of the VM such as the memory model
910	  and other information provided by the architecture. Verbose
911	  information will be printed at KERN_DEBUG loglevel depending
912	  on the mminit_loglevel= command-line option.
913
914	  If unsure, say Y
915
916config MEMORY_NOTIFIER_ERROR_INJECT
917	tristate "Memory hotplug notifier error injection module"
918	depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
919	help
920	  This option provides the ability to inject artificial errors to
921	  memory hotplug notifier chain callbacks.  It is controlled through
922	  debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
923
924	  If the notifier call chain should be failed with some events
925	  notified, write the error code to "actions/<notifier event>/error".
926
927	  Example: Inject memory hotplug offline error (-12 == -ENOMEM)
928
929	  # cd /sys/kernel/debug/notifier-error-inject/memory
930	  # echo -12 > actions/MEM_GOING_OFFLINE/error
931	  # echo offline > /sys/devices/system/memory/memoryXXX/state
932	  bash: echo: write error: Cannot allocate memory
933
934	  To compile this code as a module, choose M here: the module will
935	  be called memory-notifier-error-inject.
936
937	  If unsure, say N.
938
939config DEBUG_PER_CPU_MAPS
940	bool "Debug access to per_cpu maps"
941	depends on DEBUG_KERNEL
942	depends on SMP
943	help
944	  Say Y to verify that the per_cpu map being accessed has
945	  been set up. This adds a fair amount of code to kernel memory
946	  and decreases performance.
947
948	  Say N if unsure.
949
950config DEBUG_KMAP_LOCAL
951	bool "Debug kmap_local temporary mappings"
952	depends on DEBUG_KERNEL && KMAP_LOCAL
953	help
954	  This option enables additional error checking for the kmap_local
955	  infrastructure.  Disable for production use.
956
957config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
958	bool
959
960config DEBUG_KMAP_LOCAL_FORCE_MAP
961	bool "Enforce kmap_local temporary mappings"
962	depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
963	select KMAP_LOCAL
964	select DEBUG_KMAP_LOCAL
965	help
966	  This option enforces temporary mappings through the kmap_local
967	  mechanism for non-highmem pages and on non-highmem systems.
968	  Disable this for production systems!
969
970config DEBUG_HIGHMEM
971	bool "Highmem debugging"
972	depends on DEBUG_KERNEL && HIGHMEM
973	select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
974	select DEBUG_KMAP_LOCAL
975	help
976	  This option enables additional error checking for high memory
977	  systems.  Disable for production systems.
978
979config HAVE_DEBUG_STACKOVERFLOW
980	bool
981
982config DEBUG_STACKOVERFLOW
983	bool "Check for stack overflows"
984	depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
985	help
986	  Say Y here if you want to check for overflows of kernel, IRQ
987	  and exception stacks (if your architecture uses them). This
988	  option will show detailed messages if free stack space drops
989	  below a certain limit.
990
991	  These kinds of bugs usually occur when call-chains in the
992	  kernel get too deep, especially when interrupts are
993	  involved.
994
995	  Use this in cases where you see apparently random memory
996	  corruption, especially if it appears in 'struct thread_info'
997
998	  If in doubt, say "N".
999
1000config CODE_TAGGING
1001	bool
1002	select KALLSYMS
1003
1004config MEM_ALLOC_PROFILING
1005	bool "Enable memory allocation profiling"
1006	default n
1007	depends on MMU
1008	depends on PROC_FS
1009	depends on !DEBUG_FORCE_WEAK_PER_CPU
1010	select CODE_TAGGING
1011	select PAGE_EXTENSION
1012	select SLAB_OBJ_EXT
1013	help
1014	  Track allocation source code and record total allocation size
1015	  initiated at that code location. The mechanism can be used to track
1016	  memory leaks with a low performance and memory impact.
1017
1018config MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
1019	bool "Enable memory allocation profiling by default"
1020	default y
1021	depends on MEM_ALLOC_PROFILING
1022
1023config MEM_ALLOC_PROFILING_DEBUG
1024	bool "Memory allocation profiler debugging"
1025	default n
1026	depends on MEM_ALLOC_PROFILING
1027	select MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
1028	help
1029	  Adds warnings with helpful error messages for memory allocation
1030	  profiling.
1031
1032source "lib/Kconfig.kasan"
1033source "lib/Kconfig.kfence"
1034source "lib/Kconfig.kmsan"
1035
1036endmenu # "Memory Debugging"
1037
1038config DEBUG_SHIRQ
1039	bool "Debug shared IRQ handlers"
1040	depends on DEBUG_KERNEL
1041	help
1042	  Enable this to generate a spurious interrupt just before a shared
1043	  interrupt handler is deregistered (generating one when registering
1044	  is currently disabled). Drivers need to handle this correctly. Some
1045	  don't and need to be caught.
1046
1047menu "Debug Oops, Lockups and Hangs"
1048
1049config PANIC_ON_OOPS
1050	bool "Panic on Oops"
1051	help
1052	  Say Y here to enable the kernel to panic when it oopses. This
1053	  has the same effect as setting oops=panic on the kernel command
1054	  line.
1055
1056	  This feature is useful to ensure that the kernel does not do
1057	  anything erroneous after an oops which could result in data
1058	  corruption or other issues.
1059
1060	  Say N if unsure.
1061
1062config PANIC_ON_OOPS_VALUE
1063	int
1064	range 0 1
1065	default 0 if !PANIC_ON_OOPS
1066	default 1 if PANIC_ON_OOPS
1067
1068config PANIC_TIMEOUT
1069	int "panic timeout"
1070	default 0
1071	help
1072	  Set the timeout value (in seconds) until a reboot occurs when
1073	  the kernel panics. If n = 0, then we wait forever. A timeout
1074	  value n > 0 will wait n seconds before rebooting, while a timeout
1075	  value n < 0 will reboot immediately. This setting can be overridden
1076	  with the kernel command line option panic=, and from userspace via
1077	  /proc/sys/kernel/panic.
1078
1079config LOCKUP_DETECTOR
1080	bool
1081
1082config SOFTLOCKUP_DETECTOR
1083	bool "Detect Soft Lockups"
1084	depends on DEBUG_KERNEL && !S390
1085	select LOCKUP_DETECTOR
1086	help
1087	  Say Y here to enable the kernel to act as a watchdog to detect
1088	  soft lockups.
1089
1090	  Softlockups are bugs that cause the kernel to loop in kernel
1091	  mode for more than 20 seconds, without giving other tasks a
1092	  chance to run.  The current stack trace is displayed upon
1093	  detection and the system will stay locked up.
1094
1095config SOFTLOCKUP_DETECTOR_INTR_STORM
1096	bool "Detect Interrupt Storm in Soft Lockups"
1097	depends on SOFTLOCKUP_DETECTOR && IRQ_TIME_ACCOUNTING
1098	select GENERIC_IRQ_STAT_SNAPSHOT
1099	default y if NR_CPUS <= 128
1100	help
1101	  Say Y here to enable the kernel to detect interrupt storm
1102	  during "soft lockups".
1103
1104	  "soft lockups" can be caused by a variety of reasons. If one is
1105	  caused by an interrupt storm, then the storming interrupts will not
1106	  be on the callstack. To detect this case, it is necessary to report
1107	  the CPU stats and the interrupt counts during the "soft lockups".
1108
1109config BOOTPARAM_SOFTLOCKUP_PANIC
1110	bool "Panic (Reboot) On Soft Lockups"
1111	depends on SOFTLOCKUP_DETECTOR
1112	help
1113	  Say Y here to enable the kernel to panic on "soft lockups",
1114	  which are bugs that cause the kernel to loop in kernel
1115	  mode for more than 20 seconds (configurable using the watchdog_thresh
1116	  sysctl), without giving other tasks a chance to run.
1117
1118	  The panic can be used in combination with panic_timeout,
1119	  to cause the system to reboot automatically after a
1120	  lockup has been detected. This feature is useful for
1121	  high-availability systems that have uptime guarantees and
1122	  where a lockup must be resolved ASAP.
1123
1124	  Say N if unsure.
1125
1126config HAVE_HARDLOCKUP_DETECTOR_BUDDY
1127	bool
1128	depends on SMP
1129	default y
1130
1131#
1132# Global switch whether to build a hardlockup detector at all. It is available
1133# only when the architecture supports at least one implementation. There are
1134# two exceptions. The hardlockup detector is never enabled on:
1135#
1136#	s390: it reported many false positives there
1137#
1138#	sparc64: has a custom implementation which is not using the common
1139#		hardlockup command line options and sysctl interface.
1140#
1141config HARDLOCKUP_DETECTOR
1142	bool "Detect Hard Lockups"
1143	depends on DEBUG_KERNEL && !S390 && !HARDLOCKUP_DETECTOR_SPARC64
1144	depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_BUDDY || HAVE_HARDLOCKUP_DETECTOR_ARCH
1145	imply HARDLOCKUP_DETECTOR_PERF
1146	imply HARDLOCKUP_DETECTOR_BUDDY
1147	imply HARDLOCKUP_DETECTOR_ARCH
1148	select LOCKUP_DETECTOR
1149
1150	help
1151	  Say Y here to enable the kernel to act as a watchdog to detect
1152	  hard lockups.
1153
1154	  Hardlockups are bugs that cause the CPU to loop in kernel mode
1155	  for more than 10 seconds, without letting other interrupts have a
1156	  chance to run.  The current stack trace is displayed upon detection
1157	  and the system will stay locked up.
1158
1159#
1160# Note that arch-specific variants are always preferred.
1161#
1162config HARDLOCKUP_DETECTOR_PREFER_BUDDY
1163	bool "Prefer the buddy CPU hardlockup detector"
1164	depends on HARDLOCKUP_DETECTOR
1165	depends on HAVE_HARDLOCKUP_DETECTOR_PERF && HAVE_HARDLOCKUP_DETECTOR_BUDDY
1166	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1167	help
1168	  Say Y here to prefer the buddy hardlockup detector over the perf one.
1169
1170	  With the buddy detector, each CPU uses its softlockup hrtimer
1171	  to check that the next CPU is processing hrtimer interrupts by
1172	  verifying that a counter is increasing.
1173
1174	  This hardlockup detector is useful on systems that don't have
1175	  an arch-specific hardlockup detector or if resources needed
1176	  for the hardlockup detector are better used for other things.
1177
1178config HARDLOCKUP_DETECTOR_PERF
1179	bool
1180	depends on HARDLOCKUP_DETECTOR
1181	depends on HAVE_HARDLOCKUP_DETECTOR_PERF && !HARDLOCKUP_DETECTOR_PREFER_BUDDY
1182	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1183	select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1184
1185config HARDLOCKUP_DETECTOR_BUDDY
1186	bool
1187	depends on HARDLOCKUP_DETECTOR
1188	depends on HAVE_HARDLOCKUP_DETECTOR_BUDDY
1189	depends on !HAVE_HARDLOCKUP_DETECTOR_PERF || HARDLOCKUP_DETECTOR_PREFER_BUDDY
1190	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1191	select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1192
1193config HARDLOCKUP_DETECTOR_ARCH
1194	bool
1195	depends on HARDLOCKUP_DETECTOR
1196	depends on HAVE_HARDLOCKUP_DETECTOR_ARCH
1197	help
1198	  The arch-specific implementation of the hardlockup detector will
1199	  be used.
1200
1201#
1202# Both the "perf" and "buddy" hardlockup detectors count hrtimer
1203# interrupts. This config enables functions managing this common code.
1204#
1205config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1206	bool
1207	select SOFTLOCKUP_DETECTOR
1208
1209#
1210# Enables a timestamp based low pass filter to compensate for perf based
1211# hard lockup detection which runs too fast due to turbo modes.
1212#
1213config HARDLOCKUP_CHECK_TIMESTAMP
1214	bool
1215
1216config BOOTPARAM_HARDLOCKUP_PANIC
1217	bool "Panic (Reboot) On Hard Lockups"
1218	depends on HARDLOCKUP_DETECTOR
1219	help
1220	  Say Y here to enable the kernel to panic on "hard lockups",
1221	  which are bugs that cause the kernel to loop in kernel
1222	  mode with interrupts disabled for more than 10 seconds (configurable
1223	  using the watchdog_thresh sysctl).
1224
1225	  Say N if unsure.
1226
1227config DETECT_HUNG_TASK
1228	bool "Detect Hung Tasks"
1229	depends on DEBUG_KERNEL
1230	default SOFTLOCKUP_DETECTOR
1231	help
1232	  Say Y here to enable the kernel to detect "hung tasks",
1233	  which are bugs that cause the task to be stuck in
1234	  uninterruptible "D" state indefinitely.
1235
1236	  When a hung task is detected, the kernel will print the
1237	  current stack trace (which you should report), but the
1238	  task will stay in uninterruptible state. If lockdep is
1239	  enabled then all held locks will also be reported. This
1240	  feature has negligible overhead.
1241
1242config DEFAULT_HUNG_TASK_TIMEOUT
1243	int "Default timeout for hung task detection (in seconds)"
1244	depends on DETECT_HUNG_TASK
1245	default 120
1246	help
1247	  This option controls the default timeout (in seconds) used
1248	  to determine when a task has become non-responsive and should
1249	  be considered hung.
1250
1251	  It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1252	  sysctl or by writing a value to
1253	  /proc/sys/kernel/hung_task_timeout_secs.
1254
1255	  A timeout of 0 disables the check.  The default is two minutes.
1256	  Keeping the default should be fine in most cases.
1257
1258config BOOTPARAM_HUNG_TASK_PANIC
1259	bool "Panic (Reboot) On Hung Tasks"
1260	depends on DETECT_HUNG_TASK
1261	help
1262	  Say Y here to enable the kernel to panic on "hung tasks",
1263	  which are bugs that cause the kernel to leave a task stuck
1264	  in uninterruptible "D" state.
1265
1266	  The panic can be used in combination with panic_timeout,
1267	  to cause the system to reboot automatically after a
1268	  hung task has been detected. This feature is useful for
1269	  high-availability systems that have uptime guarantees and
1270	  where a hung tasks must be resolved ASAP.
1271
1272	  Say N if unsure.
1273
1274config WQ_WATCHDOG
1275	bool "Detect Workqueue Stalls"
1276	depends on DEBUG_KERNEL
1277	help
1278	  Say Y here to enable stall detection on workqueues.  If a
1279	  worker pool doesn't make forward progress on a pending work
1280	  item for over a given amount of time, 30s by default, a
1281	  warning message is printed along with dump of workqueue
1282	  state.  This can be configured through kernel parameter
1283	  "workqueue.watchdog_thresh" and its sysfs counterpart.
1284
1285config WQ_CPU_INTENSIVE_REPORT
1286	bool "Report per-cpu work items which hog CPU for too long"
1287	depends on DEBUG_KERNEL
1288	help
1289	  Say Y here to enable reporting of concurrency-managed per-cpu work
1290	  items that hog CPUs for longer than
1291	  workqueue.cpu_intensive_thresh_us. Workqueue automatically
1292	  detects and excludes them from concurrency management to prevent
1293	  them from stalling other per-cpu work items. Occassional
1294	  triggering may not necessarily indicate a problem. Repeated
1295	  triggering likely indicates that the work item should be switched
1296	  to use an unbound workqueue.
1297
1298config TEST_LOCKUP
1299	tristate "Test module to generate lockups"
1300	depends on m
1301	help
1302	  This builds the "test_lockup" module that helps to make sure
1303	  that watchdogs and lockup detectors are working properly.
1304
1305	  Depending on module parameters it could emulate soft or hard
1306	  lockup, "hung task", or locking arbitrary lock for a long time.
1307	  Also it could generate series of lockups with cooling-down periods.
1308
1309	  If unsure, say N.
1310
1311endmenu # "Debug lockups and hangs"
1312
1313menu "Scheduler Debugging"
1314
1315config SCHED_DEBUG
1316	bool "Collect scheduler debugging info"
1317	depends on DEBUG_KERNEL && DEBUG_FS
1318	default y
1319	help
1320	  If you say Y here, the /sys/kernel/debug/sched file will be provided
1321	  that can help debug the scheduler. The runtime overhead of this
1322	  option is minimal.
1323
1324config SCHED_INFO
1325	bool
1326	default n
1327
1328config SCHEDSTATS
1329	bool "Collect scheduler statistics"
1330	depends on PROC_FS
1331	select SCHED_INFO
1332	help
1333	  If you say Y here, additional code will be inserted into the
1334	  scheduler and related routines to collect statistics about
1335	  scheduler behavior and provide them in /proc/schedstat.  These
1336	  stats may be useful for both tuning and debugging the scheduler
1337	  If you aren't debugging the scheduler or trying to tune a specific
1338	  application, you can say N to avoid the very slight overhead
1339	  this adds.
1340
1341endmenu
1342
1343config DEBUG_PREEMPT
1344	bool "Debug preemptible kernel"
1345	depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1346	help
1347	  If you say Y here then the kernel will use a debug variant of the
1348	  commonly used smp_processor_id() function and will print warnings
1349	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
1350	  will detect preemption count underflows.
1351
1352	  This option has potential to introduce high runtime overhead,
1353	  depending on workload as it triggers debugging routines for each
1354	  this_cpu operation. It should only be used for debugging purposes.
1355
1356menu "Lock Debugging (spinlocks, mutexes, etc...)"
1357
1358config LOCK_DEBUGGING_SUPPORT
1359	bool
1360	depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1361	default y
1362
1363config PROVE_LOCKING
1364	bool "Lock debugging: prove locking correctness"
1365	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1366	select LOCKDEP
1367	select DEBUG_SPINLOCK
1368	select DEBUG_MUTEXES if !PREEMPT_RT
1369	select DEBUG_RT_MUTEXES if RT_MUTEXES
1370	select DEBUG_RWSEMS if !PREEMPT_RT
1371	select DEBUG_WW_MUTEX_SLOWPATH
1372	select DEBUG_LOCK_ALLOC
1373	select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1374	select TRACE_IRQFLAGS
1375	default n
1376	help
1377	 This feature enables the kernel to prove that all locking
1378	 that occurs in the kernel runtime is mathematically
1379	 correct: that under no circumstance could an arbitrary (and
1380	 not yet triggered) combination of observed locking
1381	 sequences (on an arbitrary number of CPUs, running an
1382	 arbitrary number of tasks and interrupt contexts) cause a
1383	 deadlock.
1384
1385	 In short, this feature enables the kernel to report locking
1386	 related deadlocks before they actually occur.
1387
1388	 The proof does not depend on how hard and complex a
1389	 deadlock scenario would be to trigger: how many
1390	 participant CPUs, tasks and irq-contexts would be needed
1391	 for it to trigger. The proof also does not depend on
1392	 timing: if a race and a resulting deadlock is possible
1393	 theoretically (no matter how unlikely the race scenario
1394	 is), it will be proven so and will immediately be
1395	 reported by the kernel (once the event is observed that
1396	 makes the deadlock theoretically possible).
1397
1398	 If a deadlock is impossible (i.e. the locking rules, as
1399	 observed by the kernel, are mathematically correct), the
1400	 kernel reports nothing.
1401
1402	 NOTE: this feature can also be enabled for rwlocks, mutexes
1403	 and rwsems - in which case all dependencies between these
1404	 different locking variants are observed and mapped too, and
1405	 the proof of observed correctness is also maintained for an
1406	 arbitrary combination of these separate locking variants.
1407
1408	 For more details, see Documentation/locking/lockdep-design.rst.
1409
1410config PROVE_RAW_LOCK_NESTING
1411	bool "Enable raw_spinlock - spinlock nesting checks" if !ARCH_SUPPORTS_RT
1412	depends on PROVE_LOCKING
1413	default y if ARCH_SUPPORTS_RT
1414	help
1415	 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1416	 that the lock nesting rules for PREEMPT_RT enabled kernels are
1417	 not violated.
1418
1419config LOCK_STAT
1420	bool "Lock usage statistics"
1421	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1422	select LOCKDEP
1423	select DEBUG_SPINLOCK
1424	select DEBUG_MUTEXES if !PREEMPT_RT
1425	select DEBUG_RT_MUTEXES if RT_MUTEXES
1426	select DEBUG_LOCK_ALLOC
1427	default n
1428	help
1429	 This feature enables tracking lock contention points
1430
1431	 For more details, see Documentation/locking/lockstat.rst
1432
1433	 This also enables lock events required by "perf lock",
1434	 subcommand of perf.
1435	 If you want to use "perf lock", you also need to turn on
1436	 CONFIG_EVENT_TRACING.
1437
1438	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1439	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1440
1441config DEBUG_RT_MUTEXES
1442	bool "RT Mutex debugging, deadlock detection"
1443	depends on DEBUG_KERNEL && RT_MUTEXES
1444	help
1445	 This allows rt mutex semantics violations and rt mutex related
1446	 deadlocks (lockups) to be detected and reported automatically.
1447
1448config DEBUG_SPINLOCK
1449	bool "Spinlock and rw-lock debugging: basic checks"
1450	depends on DEBUG_KERNEL
1451	select UNINLINE_SPIN_UNLOCK
1452	help
1453	  Say Y here and build SMP to catch missing spinlock initialization
1454	  and certain other kinds of spinlock errors commonly made.  This is
1455	  best used in conjunction with the NMI watchdog so that spinlock
1456	  deadlocks are also debuggable.
1457
1458config DEBUG_MUTEXES
1459	bool "Mutex debugging: basic checks"
1460	depends on DEBUG_KERNEL && !PREEMPT_RT
1461	help
1462	 This feature allows mutex semantics violations to be detected and
1463	 reported.
1464
1465config DEBUG_WW_MUTEX_SLOWPATH
1466	bool "Wait/wound mutex debugging: Slowpath testing"
1467	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1468	select DEBUG_LOCK_ALLOC
1469	select DEBUG_SPINLOCK
1470	select DEBUG_MUTEXES if !PREEMPT_RT
1471	select DEBUG_RT_MUTEXES if PREEMPT_RT
1472	help
1473	 This feature enables slowpath testing for w/w mutex users by
1474	 injecting additional -EDEADLK wound/backoff cases. Together with
1475	 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1476	 will test all possible w/w mutex interface abuse with the
1477	 exception of simply not acquiring all the required locks.
1478	 Note that this feature can introduce significant overhead, so
1479	 it really should not be enabled in a production or distro kernel,
1480	 even a debug kernel.  If you are a driver writer, enable it.  If
1481	 you are a distro, do not.
1482
1483config DEBUG_RWSEMS
1484	bool "RW Semaphore debugging: basic checks"
1485	depends on DEBUG_KERNEL && !PREEMPT_RT
1486	help
1487	  This debugging feature allows mismatched rw semaphore locks
1488	  and unlocks to be detected and reported.
1489
1490config DEBUG_LOCK_ALLOC
1491	bool "Lock debugging: detect incorrect freeing of live locks"
1492	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1493	select DEBUG_SPINLOCK
1494	select DEBUG_MUTEXES if !PREEMPT_RT
1495	select DEBUG_RT_MUTEXES if RT_MUTEXES
1496	select LOCKDEP
1497	help
1498	 This feature will check whether any held lock (spinlock, rwlock,
1499	 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1500	 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1501	 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1502	 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1503	 held during task exit.
1504
1505config LOCKDEP
1506	bool
1507	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1508	select STACKTRACE
1509	select KALLSYMS
1510	select KALLSYMS_ALL
1511
1512config LOCKDEP_SMALL
1513	bool
1514
1515config LOCKDEP_BITS
1516	int "Size for MAX_LOCKDEP_ENTRIES (as Nth power of 2)"
1517	depends on LOCKDEP && !LOCKDEP_SMALL
1518	range 10 24
1519	default 15
1520	help
1521	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1522
1523config LOCKDEP_CHAINS_BITS
1524	int "Size for MAX_LOCKDEP_CHAINS (as Nth power of 2)"
1525	depends on LOCKDEP && !LOCKDEP_SMALL
1526	range 10 21
1527	default 16
1528	help
1529	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1530
1531config LOCKDEP_STACK_TRACE_BITS
1532	int "Size for MAX_STACK_TRACE_ENTRIES (as Nth power of 2)"
1533	depends on LOCKDEP && !LOCKDEP_SMALL
1534	range 10 26
1535	default 19
1536	help
1537	  Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1538
1539config LOCKDEP_STACK_TRACE_HASH_BITS
1540	int "Size for STACK_TRACE_HASH_SIZE (as Nth power of 2)"
1541	depends on LOCKDEP && !LOCKDEP_SMALL
1542	range 10 26
1543	default 14
1544	help
1545	  Try increasing this value if you need large STACK_TRACE_HASH_SIZE.
1546
1547config LOCKDEP_CIRCULAR_QUEUE_BITS
1548	int "Size for elements in circular_queue struct (as Nth power of 2)"
1549	depends on LOCKDEP
1550	range 10 26
1551	default 12
1552	help
1553	  Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1554
1555config DEBUG_LOCKDEP
1556	bool "Lock dependency engine debugging"
1557	depends on DEBUG_KERNEL && LOCKDEP
1558	select DEBUG_IRQFLAGS
1559	help
1560	  If you say Y here, the lock dependency engine will do
1561	  additional runtime checks to debug itself, at the price
1562	  of more runtime overhead.
1563
1564config DEBUG_ATOMIC_SLEEP
1565	bool "Sleep inside atomic section checking"
1566	select PREEMPT_COUNT
1567	depends on DEBUG_KERNEL
1568	depends on !ARCH_NO_PREEMPT
1569	help
1570	  If you say Y here, various routines which may sleep will become very
1571	  noisy if they are called inside atomic sections: when a spinlock is
1572	  held, inside an rcu read side critical section, inside preempt disabled
1573	  sections, inside an interrupt, etc...
1574
1575config DEBUG_LOCKING_API_SELFTESTS
1576	bool "Locking API boot-time self-tests"
1577	depends on DEBUG_KERNEL
1578	help
1579	  Say Y here if you want the kernel to run a short self-test during
1580	  bootup. The self-test checks whether common types of locking bugs
1581	  are detected by debugging mechanisms or not. (if you disable
1582	  lock debugging then those bugs won't be detected of course.)
1583	  The following locking APIs are covered: spinlocks, rwlocks,
1584	  mutexes and rwsems.
1585
1586config LOCK_TORTURE_TEST
1587	tristate "torture tests for locking"
1588	depends on DEBUG_KERNEL
1589	select TORTURE_TEST
1590	help
1591	  This option provides a kernel module that runs torture tests
1592	  on kernel locking primitives.  The kernel module may be built
1593	  after the fact on the running kernel to be tested, if desired.
1594
1595	  Say Y here if you want kernel locking-primitive torture tests
1596	  to be built into the kernel.
1597	  Say M if you want these torture tests to build as a module.
1598	  Say N if you are unsure.
1599
1600config WW_MUTEX_SELFTEST
1601	tristate "Wait/wound mutex selftests"
1602	help
1603	  This option provides a kernel module that runs tests on the
1604	  on the struct ww_mutex locking API.
1605
1606	  It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1607	  with this test harness.
1608
1609	  Say M if you want these self tests to build as a module.
1610	  Say N if you are unsure.
1611
1612config SCF_TORTURE_TEST
1613	tristate "torture tests for smp_call_function*()"
1614	depends on DEBUG_KERNEL
1615	select TORTURE_TEST
1616	help
1617	  This option provides a kernel module that runs torture tests
1618	  on the smp_call_function() family of primitives.  The kernel
1619	  module may be built after the fact on the running kernel to
1620	  be tested, if desired.
1621
1622config CSD_LOCK_WAIT_DEBUG
1623	bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1624	depends on DEBUG_KERNEL
1625	depends on SMP
1626	depends on 64BIT
1627	default n
1628	help
1629	  This option enables debug prints when CPUs are slow to respond
1630	  to the smp_call_function*() IPI wrappers.  These debug prints
1631	  include the IPI handler function currently executing (if any)
1632	  and relevant stack traces.
1633
1634config CSD_LOCK_WAIT_DEBUG_DEFAULT
1635	bool "Default csd_lock_wait() debugging on at boot time"
1636	depends on CSD_LOCK_WAIT_DEBUG
1637	depends on 64BIT
1638	default n
1639	help
1640	  This option causes the csdlock_debug= kernel boot parameter to
1641	  default to 1 (basic debugging) instead of 0 (no debugging).
1642
1643endmenu # lock debugging
1644
1645config TRACE_IRQFLAGS
1646	depends on TRACE_IRQFLAGS_SUPPORT
1647	bool
1648	help
1649	  Enables hooks to interrupt enabling and disabling for
1650	  either tracing or lock debugging.
1651
1652config TRACE_IRQFLAGS_NMI
1653	def_bool y
1654	depends on TRACE_IRQFLAGS
1655	depends on TRACE_IRQFLAGS_NMI_SUPPORT
1656
1657config NMI_CHECK_CPU
1658	bool "Debugging for CPUs failing to respond to backtrace requests"
1659	depends on DEBUG_KERNEL
1660	depends on X86
1661	default n
1662	help
1663	  Enables debug prints when a CPU fails to respond to a given
1664	  backtrace NMI.  These prints provide some reasons why a CPU
1665	  might legitimately be failing to respond, for example, if it
1666	  is offline of if ignore_nmis is set.
1667
1668config DEBUG_IRQFLAGS
1669	bool "Debug IRQ flag manipulation"
1670	help
1671	  Enables checks for potentially unsafe enabling or disabling of
1672	  interrupts, such as calling raw_local_irq_restore() when interrupts
1673	  are enabled.
1674
1675config STACKTRACE
1676	bool "Stack backtrace support"
1677	depends on STACKTRACE_SUPPORT
1678	help
1679	  This option causes the kernel to create a /proc/pid/stack for
1680	  every process, showing its current stack trace.
1681	  It is also used by various kernel debugging features that require
1682	  stack trace generation.
1683
1684config WARN_ALL_UNSEEDED_RANDOM
1685	bool "Warn for all uses of unseeded randomness"
1686	default n
1687	help
1688	  Some parts of the kernel contain bugs relating to their use of
1689	  cryptographically secure random numbers before it's actually possible
1690	  to generate those numbers securely. This setting ensures that these
1691	  flaws don't go unnoticed, by enabling a message, should this ever
1692	  occur. This will allow people with obscure setups to know when things
1693	  are going wrong, so that they might contact developers about fixing
1694	  it.
1695
1696	  Unfortunately, on some models of some architectures getting
1697	  a fully seeded CRNG is extremely difficult, and so this can
1698	  result in dmesg getting spammed for a surprisingly long
1699	  time.  This is really bad from a security perspective, and
1700	  so architecture maintainers really need to do what they can
1701	  to get the CRNG seeded sooner after the system is booted.
1702	  However, since users cannot do anything actionable to
1703	  address this, by default this option is disabled.
1704
1705	  Say Y here if you want to receive warnings for all uses of
1706	  unseeded randomness.  This will be of use primarily for
1707	  those developers interested in improving the security of
1708	  Linux kernels running on their architecture (or
1709	  subarchitecture).
1710
1711config DEBUG_KOBJECT
1712	bool "kobject debugging"
1713	depends on DEBUG_KERNEL
1714	help
1715	  If you say Y here, some extra kobject debugging messages will be sent
1716	  to the syslog.
1717
1718config DEBUG_KOBJECT_RELEASE
1719	bool "kobject release debugging"
1720	depends on DEBUG_OBJECTS_TIMERS
1721	help
1722	  kobjects are reference counted objects.  This means that their
1723	  last reference count put is not predictable, and the kobject can
1724	  live on past the point at which a driver decides to drop its
1725	  initial reference to the kobject gained on allocation.  An
1726	  example of this would be a struct device which has just been
1727	  unregistered.
1728
1729	  However, some buggy drivers assume that after such an operation,
1730	  the memory backing the kobject can be immediately freed.  This
1731	  goes completely against the principles of a refcounted object.
1732
1733	  If you say Y here, the kernel will delay the release of kobjects
1734	  on the last reference count to improve the visibility of this
1735	  kind of kobject release bug.
1736
1737config HAVE_DEBUG_BUGVERBOSE
1738	bool
1739
1740menu "Debug kernel data structures"
1741
1742config DEBUG_LIST
1743	bool "Debug linked list manipulation"
1744	depends on DEBUG_KERNEL
1745	select LIST_HARDENED
1746	help
1747	  Enable this to turn on extended checks in the linked-list walking
1748	  routines.
1749
1750	  This option trades better quality error reports for performance, and
1751	  is more suitable for kernel debugging. If you care about performance,
1752	  you should only enable CONFIG_LIST_HARDENED instead.
1753
1754	  If unsure, say N.
1755
1756config DEBUG_PLIST
1757	bool "Debug priority linked list manipulation"
1758	depends on DEBUG_KERNEL
1759	help
1760	  Enable this to turn on extended checks in the priority-ordered
1761	  linked-list (plist) walking routines.  This checks the entire
1762	  list multiple times during each manipulation.
1763
1764	  If unsure, say N.
1765
1766config DEBUG_SG
1767	bool "Debug SG table operations"
1768	depends on DEBUG_KERNEL
1769	help
1770	  Enable this to turn on checks on scatter-gather tables. This can
1771	  help find problems with drivers that do not properly initialize
1772	  their sg tables.
1773
1774	  If unsure, say N.
1775
1776config DEBUG_NOTIFIERS
1777	bool "Debug notifier call chains"
1778	depends on DEBUG_KERNEL
1779	help
1780	  Enable this to turn on sanity checking for notifier call chains.
1781	  This is most useful for kernel developers to make sure that
1782	  modules properly unregister themselves from notifier chains.
1783	  This is a relatively cheap check but if you care about maximum
1784	  performance, say N.
1785
1786config DEBUG_CLOSURES
1787	bool "Debug closures (bcache async widgits)"
1788	depends on CLOSURES
1789	select DEBUG_FS
1790	help
1791	  Keeps all active closures in a linked list and provides a debugfs
1792	  interface to list them, which makes it possible to see asynchronous
1793	  operations that get stuck.
1794
1795config DEBUG_MAPLE_TREE
1796	bool "Debug maple trees"
1797	depends on DEBUG_KERNEL
1798	help
1799	  Enable maple tree debugging information and extra validations.
1800
1801	  If unsure, say N.
1802
1803endmenu
1804
1805source "kernel/rcu/Kconfig.debug"
1806
1807config DEBUG_WQ_FORCE_RR_CPU
1808	bool "Force round-robin CPU selection for unbound work items"
1809	depends on DEBUG_KERNEL
1810	default n
1811	help
1812	  Workqueue used to implicitly guarantee that work items queued
1813	  without explicit CPU specified are put on the local CPU.  This
1814	  guarantee is no longer true and while local CPU is still
1815	  preferred work items may be put on foreign CPUs.  Kernel
1816	  parameter "workqueue.debug_force_rr_cpu" is added to force
1817	  round-robin CPU selection to flush out usages which depend on the
1818	  now broken guarantee.  This config option enables the debug
1819	  feature by default.  When enabled, memory and cache locality will
1820	  be impacted.
1821
1822config CPU_HOTPLUG_STATE_CONTROL
1823	bool "Enable CPU hotplug state control"
1824	depends on DEBUG_KERNEL
1825	depends on HOTPLUG_CPU
1826	default n
1827	help
1828	  Allows to write steps between "offline" and "online" to the CPUs
1829	  sysfs target file so states can be stepped granular. This is a debug
1830	  option for now as the hotplug machinery cannot be stopped and
1831	  restarted at arbitrary points yet.
1832
1833	  Say N if your are unsure.
1834
1835config LATENCYTOP
1836	bool "Latency measuring infrastructure"
1837	depends on DEBUG_KERNEL
1838	depends on STACKTRACE_SUPPORT
1839	depends on PROC_FS
1840	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1841	select KALLSYMS
1842	select KALLSYMS_ALL
1843	select STACKTRACE
1844	select SCHEDSTATS
1845	help
1846	  Enable this option if you want to use the LatencyTOP tool
1847	  to find out which userspace is blocking on what kernel operations.
1848
1849config DEBUG_CGROUP_REF
1850	bool "Disable inlining of cgroup css reference count functions"
1851	depends on DEBUG_KERNEL
1852	depends on CGROUPS
1853	depends on KPROBES
1854	default n
1855	help
1856	  Force cgroup css reference count functions to not be inlined so
1857	  that they can be kprobed for debugging.
1858
1859source "kernel/trace/Kconfig"
1860
1861config PROVIDE_OHCI1394_DMA_INIT
1862	bool "Remote debugging over FireWire early on boot"
1863	depends on PCI && X86
1864	help
1865	  If you want to debug problems which hang or crash the kernel early
1866	  on boot and the crashing machine has a FireWire port, you can use
1867	  this feature to remotely access the memory of the crashed machine
1868	  over FireWire. This employs remote DMA as part of the OHCI1394
1869	  specification which is now the standard for FireWire controllers.
1870
1871	  With remote DMA, you can monitor the printk buffer remotely using
1872	  firescope and access all memory below 4GB using fireproxy from gdb.
1873	  Even controlling a kernel debugger is possible using remote DMA.
1874
1875	  Usage:
1876
1877	  If ohci1394_dma=early is used as boot parameter, it will initialize
1878	  all OHCI1394 controllers which are found in the PCI config space.
1879
1880	  As all changes to the FireWire bus such as enabling and disabling
1881	  devices cause a bus reset and thereby disable remote DMA for all
1882	  devices, be sure to have the cable plugged and FireWire enabled on
1883	  the debugging host before booting the debug target for debugging.
1884
1885	  This code (~1k) is freed after boot. By then, the firewire stack
1886	  in charge of the OHCI-1394 controllers should be used instead.
1887
1888	  See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1889
1890source "samples/Kconfig"
1891
1892config ARCH_HAS_DEVMEM_IS_ALLOWED
1893	bool
1894
1895config STRICT_DEVMEM
1896	bool "Filter access to /dev/mem"
1897	depends on MMU && DEVMEM
1898	depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1899	default y if PPC || X86 || ARM64 || S390
1900	help
1901	  If this option is disabled, you allow userspace (root) access to all
1902	  of memory, including kernel and userspace memory. Accidental
1903	  access to this is obviously disastrous, but specific access can
1904	  be used by people debugging the kernel. Note that with PAT support
1905	  enabled, even in this case there are restrictions on /dev/mem
1906	  use due to the cache aliasing requirements.
1907
1908	  If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1909	  file only allows userspace access to PCI space and the BIOS code and
1910	  data regions.  This is sufficient for dosemu and X and all common
1911	  users of /dev/mem.
1912
1913	  If in doubt, say Y.
1914
1915config IO_STRICT_DEVMEM
1916	bool "Filter I/O access to /dev/mem"
1917	depends on STRICT_DEVMEM
1918	help
1919	  If this option is disabled, you allow userspace (root) access to all
1920	  io-memory regardless of whether a driver is actively using that
1921	  range.  Accidental access to this is obviously disastrous, but
1922	  specific access can be used by people debugging kernel drivers.
1923
1924	  If this option is switched on, the /dev/mem file only allows
1925	  userspace access to *idle* io-memory ranges (see /proc/iomem) This
1926	  may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1927	  if the driver using a given range cannot be disabled.
1928
1929	  If in doubt, say Y.
1930
1931menu "$(SRCARCH) Debugging"
1932
1933source "arch/$(SRCARCH)/Kconfig.debug"
1934
1935endmenu
1936
1937menu "Kernel Testing and Coverage"
1938
1939source "lib/kunit/Kconfig"
1940
1941config NOTIFIER_ERROR_INJECTION
1942	tristate "Notifier error injection"
1943	depends on DEBUG_KERNEL
1944	select DEBUG_FS
1945	help
1946	  This option provides the ability to inject artificial errors to
1947	  specified notifier chain callbacks. It is useful to test the error
1948	  handling of notifier call chain failures.
1949
1950	  Say N if unsure.
1951
1952config PM_NOTIFIER_ERROR_INJECT
1953	tristate "PM notifier error injection module"
1954	depends on PM && NOTIFIER_ERROR_INJECTION
1955	default m if PM_DEBUG
1956	help
1957	  This option provides the ability to inject artificial errors to
1958	  PM notifier chain callbacks.  It is controlled through debugfs
1959	  interface /sys/kernel/debug/notifier-error-inject/pm
1960
1961	  If the notifier call chain should be failed with some events
1962	  notified, write the error code to "actions/<notifier event>/error".
1963
1964	  Example: Inject PM suspend error (-12 = -ENOMEM)
1965
1966	  # cd /sys/kernel/debug/notifier-error-inject/pm/
1967	  # echo -12 > actions/PM_SUSPEND_PREPARE/error
1968	  # echo mem > /sys/power/state
1969	  bash: echo: write error: Cannot allocate memory
1970
1971	  To compile this code as a module, choose M here: the module will
1972	  be called pm-notifier-error-inject.
1973
1974	  If unsure, say N.
1975
1976config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1977	tristate "OF reconfig notifier error injection module"
1978	depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1979	help
1980	  This option provides the ability to inject artificial errors to
1981	  OF reconfig notifier chain callbacks.  It is controlled
1982	  through debugfs interface under
1983	  /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1984
1985	  If the notifier call chain should be failed with some events
1986	  notified, write the error code to "actions/<notifier event>/error".
1987
1988	  To compile this code as a module, choose M here: the module will
1989	  be called of-reconfig-notifier-error-inject.
1990
1991	  If unsure, say N.
1992
1993config NETDEV_NOTIFIER_ERROR_INJECT
1994	tristate "Netdev notifier error injection module"
1995	depends on NET && NOTIFIER_ERROR_INJECTION
1996	help
1997	  This option provides the ability to inject artificial errors to
1998	  netdevice notifier chain callbacks.  It is controlled through debugfs
1999	  interface /sys/kernel/debug/notifier-error-inject/netdev
2000
2001	  If the notifier call chain should be failed with some events
2002	  notified, write the error code to "actions/<notifier event>/error".
2003
2004	  Example: Inject netdevice mtu change error (-22 = -EINVAL)
2005
2006	  # cd /sys/kernel/debug/notifier-error-inject/netdev
2007	  # echo -22 > actions/NETDEV_CHANGEMTU/error
2008	  # ip link set eth0 mtu 1024
2009	  RTNETLINK answers: Invalid argument
2010
2011	  To compile this code as a module, choose M here: the module will
2012	  be called netdev-notifier-error-inject.
2013
2014	  If unsure, say N.
2015
2016config FUNCTION_ERROR_INJECTION
2017	bool "Fault-injections of functions"
2018	depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
2019	help
2020	  Add fault injections into various functions that are annotated with
2021	  ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
2022	  value of these functions. This is useful to test error paths of code.
2023
2024	  If unsure, say N
2025
2026config FAULT_INJECTION
2027	bool "Fault-injection framework"
2028	depends on DEBUG_KERNEL
2029	help
2030	  Provide fault-injection framework.
2031	  For more details, see Documentation/fault-injection/.
2032
2033config FAILSLAB
2034	bool "Fault-injection capability for kmalloc"
2035	depends on FAULT_INJECTION
2036	help
2037	  Provide fault-injection capability for kmalloc.
2038
2039config FAIL_PAGE_ALLOC
2040	bool "Fault-injection capability for alloc_pages()"
2041	depends on FAULT_INJECTION
2042	help
2043	  Provide fault-injection capability for alloc_pages().
2044
2045config FAULT_INJECTION_USERCOPY
2046	bool "Fault injection capability for usercopy functions"
2047	depends on FAULT_INJECTION
2048	help
2049	  Provides fault-injection capability to inject failures
2050	  in usercopy functions (copy_from_user(), get_user(), ...).
2051
2052config FAIL_MAKE_REQUEST
2053	bool "Fault-injection capability for disk IO"
2054	depends on FAULT_INJECTION && BLOCK
2055	help
2056	  Provide fault-injection capability for disk IO.
2057
2058config FAIL_IO_TIMEOUT
2059	bool "Fault-injection capability for faking disk interrupts"
2060	depends on FAULT_INJECTION && BLOCK
2061	help
2062	  Provide fault-injection capability on end IO handling. This
2063	  will make the block layer "forget" an interrupt as configured,
2064	  thus exercising the error handling.
2065
2066	  Only works with drivers that use the generic timeout handling,
2067	  for others it won't do anything.
2068
2069config FAIL_FUTEX
2070	bool "Fault-injection capability for futexes"
2071	select DEBUG_FS
2072	depends on FAULT_INJECTION && FUTEX
2073	help
2074	  Provide fault-injection capability for futexes.
2075
2076config FAULT_INJECTION_DEBUG_FS
2077	bool "Debugfs entries for fault-injection capabilities"
2078	depends on FAULT_INJECTION && SYSFS && DEBUG_FS
2079	help
2080	  Enable configuration of fault-injection capabilities via debugfs.
2081
2082config FAIL_FUNCTION
2083	bool "Fault-injection capability for functions"
2084	depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
2085	help
2086	  Provide function-based fault-injection capability.
2087	  This will allow you to override a specific function with a return
2088	  with given return value. As a result, function caller will see
2089	  an error value and have to handle it. This is useful to test the
2090	  error handling in various subsystems.
2091
2092config FAIL_MMC_REQUEST
2093	bool "Fault-injection capability for MMC IO"
2094	depends on FAULT_INJECTION_DEBUG_FS && MMC
2095	help
2096	  Provide fault-injection capability for MMC IO.
2097	  This will make the mmc core return data errors. This is
2098	  useful to test the error handling in the mmc block device
2099	  and to test how the mmc host driver handles retries from
2100	  the block device.
2101
2102config FAIL_SUNRPC
2103	bool "Fault-injection capability for SunRPC"
2104	depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2105	help
2106	  Provide fault-injection capability for SunRPC and
2107	  its consumers.
2108
2109config FAIL_SKB_REALLOC
2110	bool "Fault-injection capability forcing skb to reallocate"
2111	depends on FAULT_INJECTION_DEBUG_FS
2112	help
2113	  Provide fault-injection capability that forces the skb to be
2114	  reallocated, catching possible invalid pointers to the skb.
2115
2116	  For more information, check
2117	  Documentation/fault-injection/fault-injection.rst
2118
2119config FAULT_INJECTION_CONFIGFS
2120	bool "Configfs interface for fault-injection capabilities"
2121	depends on FAULT_INJECTION
2122	select CONFIGFS_FS
2123	help
2124	  This option allows configfs-based drivers to dynamically configure
2125	  fault-injection via configfs.  Each parameter for driver-specific
2126	  fault-injection can be made visible as a configfs attribute in a
2127	  configfs group.
2128
2129
2130config FAULT_INJECTION_STACKTRACE_FILTER
2131	bool "stacktrace filter for fault-injection capabilities"
2132	depends on FAULT_INJECTION
2133	depends on (FAULT_INJECTION_DEBUG_FS || FAULT_INJECTION_CONFIGFS) && STACKTRACE_SUPPORT
2134	select STACKTRACE
2135	depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2136	help
2137	  Provide stacktrace filter for fault-injection capabilities
2138
2139config ARCH_HAS_KCOV
2140	bool
2141	help
2142	  An architecture should select this when it can successfully
2143	  build and run with CONFIG_KCOV. This typically requires
2144	  disabling instrumentation for some early boot code.
2145
2146config CC_HAS_SANCOV_TRACE_PC
2147	def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2148
2149
2150config KCOV
2151	bool "Code coverage for fuzzing"
2152	depends on ARCH_HAS_KCOV
2153	depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2154	depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2155		   GCC_VERSION >= 120000 || CC_IS_CLANG
2156	select DEBUG_FS
2157	select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2158	select OBJTOOL if HAVE_NOINSTR_HACK
2159	help
2160	  KCOV exposes kernel code coverage information in a form suitable
2161	  for coverage-guided fuzzing (randomized testing).
2162
2163	  For more details, see Documentation/dev-tools/kcov.rst.
2164
2165config KCOV_ENABLE_COMPARISONS
2166	bool "Enable comparison operands collection by KCOV"
2167	depends on KCOV
2168	depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2169	help
2170	  KCOV also exposes operands of every comparison in the instrumented
2171	  code along with operand sizes and PCs of the comparison instructions.
2172	  These operands can be used by fuzzing engines to improve the quality
2173	  of fuzzing coverage.
2174
2175config KCOV_INSTRUMENT_ALL
2176	bool "Instrument all code by default"
2177	depends on KCOV
2178	default y
2179	help
2180	  If you are doing generic system call fuzzing (like e.g. syzkaller),
2181	  then you will want to instrument the whole kernel and you should
2182	  say y here. If you are doing more targeted fuzzing (like e.g.
2183	  filesystem fuzzing with AFL) then you will want to enable coverage
2184	  for more specific subsets of files, and should say n here.
2185
2186config KCOV_IRQ_AREA_SIZE
2187	hex "Size of interrupt coverage collection area in words"
2188	depends on KCOV
2189	default 0x40000
2190	help
2191	  KCOV uses preallocated per-cpu areas to collect coverage from
2192	  soft interrupts. This specifies the size of those areas in the
2193	  number of unsigned long words.
2194
2195config KCOV_SELFTEST
2196	bool "Perform short selftests on boot"
2197	depends on KCOV
2198	help
2199	  Run short KCOV coverage collection selftests on boot.
2200	  On test failure, causes the kernel to panic. Recommended to be
2201	  enabled, ensuring critical functionality works as intended.
2202
2203menuconfig RUNTIME_TESTING_MENU
2204	bool "Runtime Testing"
2205	default y
2206
2207if RUNTIME_TESTING_MENU
2208
2209config TEST_DHRY
2210	tristate "Dhrystone benchmark test"
2211	help
2212	  Enable this to include the Dhrystone 2.1 benchmark.  This test
2213	  calculates the number of Dhrystones per second, and the number of
2214	  DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided
2215	  by 1757 (the number of Dhrystones per second obtained on the VAX
2216	  11/780, nominally a 1 MIPS machine).
2217
2218	  To run the benchmark, it needs to be enabled explicitly, either from
2219	  the kernel command line (when built-in), or from userspace (when
2220	  built-in or modular).
2221
2222	  Run once during kernel boot:
2223
2224	      test_dhry.run
2225
2226	  Set number of iterations from kernel command line:
2227
2228	      test_dhry.iterations=<n>
2229
2230	  Set number of iterations from userspace:
2231
2232	      echo <n> > /sys/module/test_dhry/parameters/iterations
2233
2234	  Trigger manual run from userspace:
2235
2236	      echo y > /sys/module/test_dhry/parameters/run
2237
2238	  If the number of iterations is <= 0, the test will devise a suitable
2239	  number of iterations (test runs for at least 2s) automatically.
2240	  This process takes ca. 4s.
2241
2242	  If unsure, say N.
2243
2244config LKDTM
2245	tristate "Linux Kernel Dump Test Tool Module"
2246	depends on DEBUG_FS
2247	help
2248	This module enables testing of the different dumping mechanisms by
2249	inducing system failures at predefined crash points.
2250	If you don't need it: say N
2251	Choose M here to compile this code as a module. The module will be
2252	called lkdtm.
2253
2254	Documentation on how to use the module can be found in
2255	Documentation/fault-injection/provoke-crashes.rst
2256
2257config CPUMASK_KUNIT_TEST
2258	tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2259	depends on KUNIT
2260	default KUNIT_ALL_TESTS
2261	help
2262	  Enable to turn on cpumask tests, running at boot or module load time.
2263
2264	  For more information on KUnit and unit tests in general, please refer
2265	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2266
2267	  If unsure, say N.
2268
2269config TEST_LIST_SORT
2270	tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2271	depends on KUNIT
2272	default KUNIT_ALL_TESTS
2273	help
2274	  Enable this to turn on 'list_sort()' function test. This test is
2275	  executed only once during system boot (so affects only boot time),
2276	  or at module load time.
2277
2278	  If unsure, say N.
2279
2280config TEST_MIN_HEAP
2281	tristate "Min heap test"
2282	depends on DEBUG_KERNEL || m
2283	help
2284	  Enable this to turn on min heap function tests. This test is
2285	  executed only once during system boot (so affects only boot time),
2286	  or at module load time.
2287
2288	  If unsure, say N.
2289
2290config TEST_SORT
2291	tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2292	depends on KUNIT
2293	default KUNIT_ALL_TESTS
2294	help
2295	  This option enables the self-test function of 'sort()' at boot,
2296	  or at module load time.
2297
2298	  If unsure, say N.
2299
2300config TEST_DIV64
2301	tristate "64bit/32bit division and modulo test"
2302	depends on DEBUG_KERNEL || m
2303	help
2304	  Enable this to turn on 'do_div()' function test. This test is
2305	  executed only once during system boot (so affects only boot time),
2306	  or at module load time.
2307
2308	  If unsure, say N.
2309
2310config TEST_MULDIV64
2311	tristate "mul_u64_u64_div_u64() test"
2312	depends on DEBUG_KERNEL || m
2313	help
2314	  Enable this to turn on 'mul_u64_u64_div_u64()' function test.
2315	  This test is executed only once during system boot (so affects
2316	  only boot time), or at module load time.
2317
2318	  If unsure, say N.
2319
2320config TEST_IOV_ITER
2321	tristate "Test iov_iter operation" if !KUNIT_ALL_TESTS
2322	depends on KUNIT
2323	depends on MMU
2324	default KUNIT_ALL_TESTS
2325	help
2326	  Enable this to turn on testing of the operation of the I/O iterator
2327	  (iov_iter). This test is executed only once during system boot (so
2328	  affects only boot time), or at module load time.
2329
2330	  If unsure, say N.
2331
2332config KPROBES_SANITY_TEST
2333	tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2334	depends on DEBUG_KERNEL
2335	depends on KPROBES
2336	depends on KUNIT
2337	select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2338	default KUNIT_ALL_TESTS
2339	help
2340	  This option provides for testing basic kprobes functionality on
2341	  boot. Samples of kprobe and kretprobe are inserted and
2342	  verified for functionality.
2343
2344	  Say N if you are unsure.
2345
2346config FPROBE_SANITY_TEST
2347	bool "Self test for fprobe"
2348	depends on DEBUG_KERNEL
2349	depends on FPROBE
2350	depends on KUNIT=y
2351	help
2352	  This option will enable testing the fprobe when the system boot.
2353	  A series of tests are made to verify that the fprobe is functioning
2354	  properly.
2355
2356	  Say N if you are unsure.
2357
2358config BACKTRACE_SELF_TEST
2359	tristate "Self test for the backtrace code"
2360	depends on DEBUG_KERNEL
2361	help
2362	  This option provides a kernel module that can be used to test
2363	  the kernel stack backtrace code. This option is not useful
2364	  for distributions or general kernels, but only for kernel
2365	  developers working on architecture code.
2366
2367	  Note that if you want to also test saved backtraces, you will
2368	  have to enable STACKTRACE as well.
2369
2370	  Say N if you are unsure.
2371
2372config TEST_REF_TRACKER
2373	tristate "Self test for reference tracker"
2374	depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2375	select REF_TRACKER
2376	help
2377	  This option provides a kernel module performing tests
2378	  using reference tracker infrastructure.
2379
2380	  Say N if you are unsure.
2381
2382config RBTREE_TEST
2383	tristate "Red-Black tree test"
2384	depends on DEBUG_KERNEL
2385	help
2386	  A benchmark measuring the performance of the rbtree library.
2387	  Also includes rbtree invariant checks.
2388
2389config REED_SOLOMON_TEST
2390	tristate "Reed-Solomon library test"
2391	depends on DEBUG_KERNEL || m
2392	select REED_SOLOMON
2393	select REED_SOLOMON_ENC16
2394	select REED_SOLOMON_DEC16
2395	help
2396	  This option enables the self-test function of rslib at boot,
2397	  or at module load time.
2398
2399	  If unsure, say N.
2400
2401config INTERVAL_TREE_TEST
2402	tristate "Interval tree test"
2403	depends on DEBUG_KERNEL
2404	select INTERVAL_TREE
2405	help
2406	  A benchmark measuring the performance of the interval tree library
2407
2408config PERCPU_TEST
2409	tristate "Per cpu operations test"
2410	depends on m && DEBUG_KERNEL
2411	help
2412	  Enable this option to build test module which validates per-cpu
2413	  operations.
2414
2415	  If unsure, say N.
2416
2417config ATOMIC64_SELFTEST
2418	tristate "Perform an atomic64_t self-test"
2419	help
2420	  Enable this option to test the atomic64_t functions at boot or
2421	  at module load time.
2422
2423	  If unsure, say N.
2424
2425config ASYNC_RAID6_TEST
2426	tristate "Self test for hardware accelerated raid6 recovery"
2427	depends on ASYNC_RAID6_RECOV
2428	select ASYNC_MEMCPY
2429	help
2430	  This is a one-shot self test that permutes through the
2431	  recovery of all the possible two disk failure scenarios for a
2432	  N-disk array.  Recovery is performed with the asynchronous
2433	  raid6 recovery routines, and will optionally use an offload
2434	  engine if one is available.
2435
2436	  If unsure, say N.
2437
2438config TEST_HEXDUMP
2439	tristate "Test functions located in the hexdump module at runtime"
2440
2441config STRING_KUNIT_TEST
2442	tristate "KUnit test string functions at runtime" if !KUNIT_ALL_TESTS
2443	depends on KUNIT
2444	default KUNIT_ALL_TESTS
2445
2446config STRING_HELPERS_KUNIT_TEST
2447	tristate "KUnit test string helpers at runtime" if !KUNIT_ALL_TESTS
2448	depends on KUNIT
2449	default KUNIT_ALL_TESTS
2450
2451config TEST_KSTRTOX
2452	tristate "Test kstrto*() family of functions at runtime"
2453
2454config TEST_PRINTF
2455	tristate "Test printf() family of functions at runtime"
2456
2457config TEST_SCANF
2458	tristate "Test scanf() family of functions at runtime"
2459
2460config TEST_BITMAP
2461	tristate "Test bitmap_*() family of functions at runtime"
2462	help
2463	  Enable this option to test the bitmap functions at boot.
2464
2465	  If unsure, say N.
2466
2467config TEST_UUID
2468	tristate "Test functions located in the uuid module at runtime"
2469
2470config TEST_XARRAY
2471	tristate "Test the XArray code at runtime"
2472
2473config TEST_MAPLE_TREE
2474	tristate "Test the Maple Tree code at runtime or module load"
2475	help
2476	  Enable this option to test the maple tree code functions at boot, or
2477	  when the module is loaded. Enable "Debug Maple Trees" will enable
2478	  more verbose output on failures.
2479
2480	  If unsure, say N.
2481
2482config TEST_RHASHTABLE
2483	tristate "Perform selftest on resizable hash table"
2484	help
2485	  Enable this option to test the rhashtable functions at boot.
2486
2487	  If unsure, say N.
2488
2489config TEST_IDA
2490	tristate "Perform selftest on IDA functions"
2491
2492config TEST_MISC_MINOR
2493	tristate "Basic misc minor Kunit test" if !KUNIT_ALL_TESTS
2494	depends on KUNIT
2495	default KUNIT_ALL_TESTS
2496	help
2497	  Kunit test for the misc minor.
2498	  It tests misc minor functions for dynamic and misc dynamic minor.
2499	  This include misc_xxx functions
2500
2501	  If unsure, say N.
2502
2503config TEST_PARMAN
2504	tristate "Perform selftest on priority array manager"
2505	depends on PARMAN
2506	help
2507	  Enable this option to test priority array manager on boot
2508	  (or module load).
2509
2510	  If unsure, say N.
2511
2512config TEST_IRQ_TIMINGS
2513	bool "IRQ timings selftest"
2514	depends on IRQ_TIMINGS
2515	help
2516	  Enable this option to test the irq timings code on boot.
2517
2518	  If unsure, say N.
2519
2520config TEST_LKM
2521	tristate "Test module loading with 'hello world' module"
2522	depends on m
2523	help
2524	  This builds the "test_module" module that emits "Hello, world"
2525	  on printk when loaded. It is designed to be used for basic
2526	  evaluation of the module loading subsystem (for example when
2527	  validating module verification). It lacks any extra dependencies,
2528	  and will not normally be loaded by the system unless explicitly
2529	  requested by name.
2530
2531	  If unsure, say N.
2532
2533config TEST_BITOPS
2534	tristate "Test module for compilation of bitops operations"
2535	help
2536	  This builds the "test_bitops" module that is much like the
2537	  TEST_LKM module except that it does a basic exercise of the
2538	  set/clear_bit macros and get_count_order/long to make sure there are
2539	  no compiler warnings from C=1 sparse checker or -Wextra
2540	  compilations. It has no dependencies and doesn't run or load unless
2541	  explicitly requested by name.  for example: modprobe test_bitops.
2542
2543	  If unsure, say N.
2544
2545config TEST_VMALLOC
2546	tristate "Test module for stress/performance analysis of vmalloc allocator"
2547	default n
2548       depends on MMU
2549	depends on m
2550	help
2551	  This builds the "test_vmalloc" module that should be used for
2552	  stress and performance analysis. So, any new change for vmalloc
2553	  subsystem can be evaluated from performance and stability point
2554	  of view.
2555
2556	  If unsure, say N.
2557
2558config TEST_BPF
2559	tristate "Test BPF filter functionality"
2560	depends on m && NET
2561	help
2562	  This builds the "test_bpf" module that runs various test vectors
2563	  against the BPF interpreter or BPF JIT compiler depending on the
2564	  current setting. This is in particular useful for BPF JIT compiler
2565	  development, but also to run regression tests against changes in
2566	  the interpreter code. It also enables test stubs for eBPF maps and
2567	  verifier used by user space verifier testsuite.
2568
2569	  If unsure, say N.
2570
2571config TEST_BLACKHOLE_DEV
2572	tristate "Test blackhole netdev functionality"
2573	depends on m && NET
2574	help
2575	  This builds the "test_blackhole_dev" module that validates the
2576	  data path through this blackhole netdev.
2577
2578	  If unsure, say N.
2579
2580config FIND_BIT_BENCHMARK
2581	tristate "Test find_bit functions"
2582	help
2583	  This builds the "test_find_bit" module that measure find_*_bit()
2584	  functions performance.
2585
2586	  If unsure, say N.
2587
2588config TEST_FIRMWARE
2589	tristate "Test firmware loading via userspace interface"
2590	depends on FW_LOADER
2591	help
2592	  This builds the "test_firmware" module that creates a userspace
2593	  interface for testing firmware loading. This can be used to
2594	  control the triggering of firmware loading without needing an
2595	  actual firmware-using device. The contents can be rechecked by
2596	  userspace.
2597
2598	  If unsure, say N.
2599
2600config TEST_SYSCTL
2601	tristate "sysctl test driver"
2602	depends on PROC_SYSCTL
2603	help
2604	  This builds the "test_sysctl" module. This driver enables to test the
2605	  proc sysctl interfaces available to drivers safely without affecting
2606	  production knobs which might alter system functionality.
2607
2608	  If unsure, say N.
2609
2610config BITFIELD_KUNIT
2611	tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2612	depends on KUNIT
2613	default KUNIT_ALL_TESTS
2614	help
2615	  Enable this option to test the bitfield functions at boot.
2616
2617	  KUnit tests run during boot and output the results to the debug log
2618	  in TAP format (http://testanything.org/). Only useful for kernel devs
2619	  running the KUnit test harness, and not intended for inclusion into a
2620	  production build.
2621
2622	  For more information on KUnit and unit tests in general please refer
2623	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2624
2625	  If unsure, say N.
2626
2627config CHECKSUM_KUNIT
2628	tristate "KUnit test checksum functions at runtime" if !KUNIT_ALL_TESTS
2629	depends on KUNIT
2630	default KUNIT_ALL_TESTS
2631	help
2632	  Enable this option to test the checksum functions at boot.
2633
2634	  KUnit tests run during boot and output the results to the debug log
2635	  in TAP format (http://testanything.org/). Only useful for kernel devs
2636	  running the KUnit test harness, and not intended for inclusion into a
2637	  production build.
2638
2639	  For more information on KUnit and unit tests in general please refer
2640	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2641
2642	  If unsure, say N.
2643
2644config UTIL_MACROS_KUNIT
2645	tristate "KUnit test util_macros.h functions at runtime" if !KUNIT_ALL_TESTS
2646	depends on KUNIT
2647	default KUNIT_ALL_TESTS
2648	help
2649	  Enable this option to test the util_macros.h function at boot.
2650
2651	  KUnit tests run during boot and output the results to the debug log
2652	  in TAP format (http://testanything.org/). Only useful for kernel devs
2653	  running the KUnit test harness, and not intended for inclusion into a
2654	  production build.
2655
2656	  For more information on KUnit and unit tests in general please refer
2657	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2658
2659	  If unsure, say N.
2660
2661config HASH_KUNIT_TEST
2662	tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2663	depends on KUNIT
2664	default KUNIT_ALL_TESTS
2665	help
2666	  Enable this option to test the kernel's string (<linux/stringhash.h>), and
2667	  integer (<linux/hash.h>) hash functions on boot.
2668
2669	  KUnit tests run during boot and output the results to the debug log
2670	  in TAP format (https://testanything.org/). Only useful for kernel devs
2671	  running the KUnit test harness, and not intended for inclusion into a
2672	  production build.
2673
2674	  For more information on KUnit and unit tests in general please refer
2675	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2676
2677	  This is intended to help people writing architecture-specific
2678	  optimized versions. If unsure, say N.
2679
2680config RESOURCE_KUNIT_TEST
2681	tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2682	depends on KUNIT
2683	default KUNIT_ALL_TESTS
2684	select GET_FREE_REGION
2685	help
2686	  This builds the resource API unit test.
2687	  Tests the logic of API provided by resource.c and ioport.h.
2688	  For more information on KUnit and unit tests in general please refer
2689	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2690
2691	  If unsure, say N.
2692
2693config SYSCTL_KUNIT_TEST
2694	tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2695	depends on KUNIT
2696	default KUNIT_ALL_TESTS
2697	help
2698	  This builds the proc sysctl unit test, which runs on boot.
2699	  Tests the API contract and implementation correctness of sysctl.
2700	  For more information on KUnit and unit tests in general please refer
2701	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2702
2703	  If unsure, say N.
2704
2705config LIST_KUNIT_TEST
2706	tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2707	depends on KUNIT
2708	default KUNIT_ALL_TESTS
2709	help
2710	  This builds the linked list KUnit test suite.
2711	  It tests that the API and basic functionality of the list_head type
2712	  and associated macros.
2713
2714	  KUnit tests run during boot and output the results to the debug log
2715	  in TAP format (https://testanything.org/). Only useful for kernel devs
2716	  running the KUnit test harness, and not intended for inclusion into a
2717	  production build.
2718
2719	  For more information on KUnit and unit tests in general please refer
2720	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2721
2722	  If unsure, say N.
2723
2724config HASHTABLE_KUNIT_TEST
2725	tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS
2726	depends on KUNIT
2727	default KUNIT_ALL_TESTS
2728	help
2729	  This builds the hashtable KUnit test suite.
2730	  It tests the basic functionality of the API defined in
2731	  include/linux/hashtable.h. For more information on KUnit and
2732	  unit tests in general please refer to the KUnit documentation
2733	  in Documentation/dev-tools/kunit/.
2734
2735	  If unsure, say N.
2736
2737config LINEAR_RANGES_TEST
2738	tristate "KUnit test for linear_ranges"
2739	depends on KUNIT
2740	select LINEAR_RANGES
2741	help
2742	  This builds the linear_ranges unit test, which runs on boot.
2743	  Tests the linear_ranges logic correctness.
2744	  For more information on KUnit and unit tests in general please refer
2745	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2746
2747	  If unsure, say N.
2748
2749config CMDLINE_KUNIT_TEST
2750	tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2751	depends on KUNIT
2752	default KUNIT_ALL_TESTS
2753	help
2754	  This builds the cmdline API unit test.
2755	  Tests the logic of API provided by cmdline.c.
2756	  For more information on KUnit and unit tests in general please refer
2757	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2758
2759	  If unsure, say N.
2760
2761config BITS_TEST
2762	tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2763	depends on KUNIT
2764	default KUNIT_ALL_TESTS
2765	help
2766	  This builds the bits unit test.
2767	  Tests the logic of macros defined in bits.h.
2768	  For more information on KUnit and unit tests in general please refer
2769	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2770
2771	  If unsure, say N.
2772
2773config SLUB_KUNIT_TEST
2774	tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2775	depends on SLUB_DEBUG && KUNIT
2776	default KUNIT_ALL_TESTS
2777	help
2778	  This builds SLUB allocator unit test.
2779	  Tests SLUB cache debugging functionality.
2780	  For more information on KUnit and unit tests in general please refer
2781	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2782
2783	  If unsure, say N.
2784
2785config RATIONAL_KUNIT_TEST
2786	tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2787	depends on KUNIT && RATIONAL
2788	default KUNIT_ALL_TESTS
2789	help
2790	  This builds the rational math unit test.
2791	  For more information on KUnit and unit tests in general please refer
2792	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2793
2794	  If unsure, say N.
2795
2796config MEMCPY_KUNIT_TEST
2797	tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2798	depends on KUNIT
2799	default KUNIT_ALL_TESTS
2800	help
2801	  Builds unit tests for memcpy(), memmove(), and memset() functions.
2802	  For more information on KUnit and unit tests in general please refer
2803	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2804
2805	  If unsure, say N.
2806
2807config IS_SIGNED_TYPE_KUNIT_TEST
2808	tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2809	depends on KUNIT
2810	default KUNIT_ALL_TESTS
2811	help
2812	  Builds unit tests for the is_signed_type() macro.
2813
2814	  For more information on KUnit and unit tests in general please refer
2815	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2816
2817	  If unsure, say N.
2818
2819config OVERFLOW_KUNIT_TEST
2820	tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2821	depends on KUNIT
2822	default KUNIT_ALL_TESTS
2823	help
2824	  Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2825	  related functions.
2826
2827	  For more information on KUnit and unit tests in general please refer
2828	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2829
2830	  If unsure, say N.
2831
2832config STACKINIT_KUNIT_TEST
2833	tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2834	depends on KUNIT
2835	default KUNIT_ALL_TESTS
2836	help
2837	  Test if the kernel is zero-initializing stack variables and
2838	  padding. Coverage is controlled by compiler flags,
2839	  CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2840	  CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2841	  or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2842
2843config FORTIFY_KUNIT_TEST
2844	tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2845	depends on KUNIT
2846	default KUNIT_ALL_TESTS
2847	help
2848	  Builds unit tests for checking internals of FORTIFY_SOURCE as used
2849	  by the str*() and mem*() family of functions. For testing runtime
2850	  traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2851
2852config HW_BREAKPOINT_KUNIT_TEST
2853	bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2854	depends on HAVE_HW_BREAKPOINT
2855	depends on KUNIT=y
2856	default KUNIT_ALL_TESTS
2857	help
2858	  Tests for hw_breakpoint constraints accounting.
2859
2860	  If unsure, say N.
2861
2862config CRC_KUNIT_TEST
2863	tristate "KUnit tests for CRC functions" if !KUNIT_ALL_TESTS
2864	depends on KUNIT
2865	default KUNIT_ALL_TESTS
2866	select CRC16
2867	select CRC_T10DIF
2868	select CRC32
2869	select CRC64
2870	help
2871	  Unit tests for the CRC library functions.
2872
2873	  This is intended to help people writing architecture-specific
2874	  optimized versions.  If unsure, say N.
2875
2876config CRC_BENCHMARK
2877	bool "Benchmark for the CRC functions"
2878	depends on CRC_KUNIT_TEST
2879	help
2880	  Include benchmarks in the KUnit test suite for the CRC functions.
2881
2882config SIPHASH_KUNIT_TEST
2883	tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2884	depends on KUNIT
2885	default KUNIT_ALL_TESTS
2886	help
2887	  Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2888	  functions on boot (or module load).
2889
2890	  This is intended to help people writing architecture-specific
2891	  optimized versions.  If unsure, say N.
2892
2893config USERCOPY_KUNIT_TEST
2894	tristate "KUnit Test for user/kernel boundary protections"
2895	depends on KUNIT
2896	default KUNIT_ALL_TESTS
2897	help
2898	  This builds the "usercopy_kunit" module that runs sanity checks
2899	  on the copy_to/from_user infrastructure, making sure basic
2900	  user/kernel boundary testing is working.
2901
2902config TEST_UDELAY
2903	tristate "udelay test driver"
2904	help
2905	  This builds the "udelay_test" module that helps to make sure
2906	  that udelay() is working properly.
2907
2908	  If unsure, say N.
2909
2910config TEST_STATIC_KEYS
2911	tristate "Test static keys"
2912	depends on m
2913	help
2914	  Test the static key interfaces.
2915
2916	  If unsure, say N.
2917
2918config TEST_DYNAMIC_DEBUG
2919	tristate "Test DYNAMIC_DEBUG"
2920	depends on DYNAMIC_DEBUG
2921	help
2922	  This module registers a tracer callback to count enabled
2923	  pr_debugs in a 'do_debugging' function, then alters their
2924	  enablements, calls the function, and compares counts.
2925
2926	  If unsure, say N.
2927
2928config TEST_KMOD
2929	tristate "kmod stress tester"
2930	depends on m
2931	depends on NETDEVICES && NET_CORE && INET # for TUN
2932	depends on BLOCK
2933	depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2934	select TEST_LKM
2935	select XFS_FS
2936	select TUN
2937	select BTRFS_FS
2938	help
2939	  Test the kernel's module loading mechanism: kmod. kmod implements
2940	  support to load modules using the Linux kernel's usermode helper.
2941	  This test provides a series of tests against kmod.
2942
2943	  Although technically you can either build test_kmod as a module or
2944	  into the kernel we disallow building it into the kernel since
2945	  it stress tests request_module() and this will very likely cause
2946	  some issues by taking over precious threads available from other
2947	  module load requests, ultimately this could be fatal.
2948
2949	  To run tests run:
2950
2951	  tools/testing/selftests/kmod/kmod.sh --help
2952
2953	  If unsure, say N.
2954
2955config TEST_RUNTIME
2956	bool
2957
2958config TEST_RUNTIME_MODULE
2959	bool
2960
2961config TEST_KALLSYMS
2962	tristate "module kallsyms find_symbol() test"
2963	depends on m
2964	select TEST_RUNTIME
2965	select TEST_RUNTIME_MODULE
2966	select TEST_KALLSYMS_A
2967	select TEST_KALLSYMS_B
2968	select TEST_KALLSYMS_C
2969	select TEST_KALLSYMS_D
2970	help
2971	  This allows us to stress test find_symbol() through the kallsyms
2972	  used to place symbols on the kernel ELF kallsyms and modules kallsyms
2973	  where we place kernel symbols such as exported symbols.
2974
2975	  We have four test modules:
2976
2977	  A: has KALLSYSMS_NUMSYMS exported symbols
2978	  B: uses one of A's symbols
2979	  C: adds KALLSYMS_SCALE_FACTOR * KALLSYSMS_NUMSYMS exported
2980	  D: adds 2 * the symbols than C
2981
2982	  We stress test find_symbol() through two means:
2983
2984	  1) Upon load of B it will trigger simplify_symbols() to look for the
2985	  one symbol it uses from the module A with tons of symbols. This is an
2986	  indirect way for us to have B call resolve_symbol_wait() upon module
2987	  load. This will eventually call find_symbol() which will eventually
2988	  try to find the symbols used with find_exported_symbol_in_section().
2989	  find_exported_symbol_in_section() uses bsearch() so a binary search
2990	  for each symbol. Binary search will at worst be O(log(n)) so the
2991	  larger TEST_MODULE_KALLSYSMS the worse the search.
2992
2993	  2) The selftests should load C first, before B. Upon B's load towards
2994	  the end right before we call module B's init routine we get
2995	  complete_formation() called on the module. That will first check
2996	  for duplicate symbols with the call to verify_exported_symbols().
2997	  That is when we'll force iteration on module C's insane symbol list.
2998	  Since it has 10 * KALLSYMS_NUMSYMS it means we can first test
2999	  just loading B without C. The amount of time it takes to load C Vs
3000	  B can give us an idea of the impact growth of the symbol space and
3001	  give us projection. Module A only uses one symbol from B so to allow
3002	  this scaling in module C to be proportional, if it used more symbols
3003	  then the first test would be doing more and increasing just the
3004	  search space would be slightly different. The last module, module D
3005	  will just increase the search space by twice the number of symbols in
3006	  C so to allow for full projects.
3007
3008	  tools/testing/selftests/module/find_symbol.sh
3009
3010	  The current defaults will incur a build delay of about 7 minutes
3011	  on an x86_64 with only 8 cores. Enable this only if you want to
3012	  stress test find_symbol() with thousands of symbols. At the same
3013	  time this is also useful to test building modules with thousands of
3014	  symbols, and if BTF is enabled this also stress tests adding BTF
3015	  information for each module. Currently enabling many more symbols
3016	  will segfault the build system.
3017
3018	  If unsure, say N.
3019
3020if TEST_KALLSYMS
3021
3022config TEST_KALLSYMS_A
3023	tristate
3024	depends on m
3025
3026config TEST_KALLSYMS_B
3027	tristate
3028	depends on m
3029
3030config TEST_KALLSYMS_C
3031	tristate
3032	depends on m
3033
3034config TEST_KALLSYMS_D
3035	tristate
3036	depends on m
3037
3038choice
3039	prompt "Kallsym test range"
3040	default TEST_KALLSYMS_LARGE
3041	help
3042	  Selecting something other than "Fast" will enable tests which slow
3043	  down the build and may crash your build.
3044
3045config TEST_KALLSYMS_FAST
3046	bool "Fast builds"
3047	help
3048	  You won't really be testing kallsysms, so this just helps fast builds
3049	  when allmodconfig is used..
3050
3051config TEST_KALLSYMS_LARGE
3052	bool "Enable testing kallsyms with large exports"
3053	help
3054	  This will enable larger number of symbols. This will slow down
3055	  your build considerably.
3056
3057config TEST_KALLSYMS_MAX
3058	bool "Known kallsysms limits"
3059	help
3060	  This will enable exports to the point we know we'll start crashing
3061	  builds.
3062
3063endchoice
3064
3065config TEST_KALLSYMS_NUMSYMS
3066	int "test kallsyms number of symbols"
3067	range 2 10000
3068	default 2 if TEST_KALLSYMS_FAST
3069	default 100 if TEST_KALLSYMS_LARGE
3070	default 10000 if TEST_KALLSYMS_MAX
3071	help
3072	  The number of symbols to create on TEST_KALLSYMS_A, only one of which
3073	  module TEST_KALLSYMS_B will use. This also will be used
3074	  for how many symbols TEST_KALLSYMS_C will have, scaled up by
3075	  TEST_KALLSYMS_SCALE_FACTOR. Note that setting this to 10,000 will
3076	  trigger a segfault today, don't use anything close to it unless
3077	  you are aware that this should not be used for automated build tests.
3078
3079config TEST_KALLSYMS_SCALE_FACTOR
3080	int "test kallsyms scale factor"
3081	default 8
3082	help
3083	  How many more unusued symbols will TEST_KALLSYSMS_C have than
3084	  TEST_KALLSYMS_A. If 8, then module C will have 8 * syms
3085	  than module A. Then TEST_KALLSYMS_D will have double the amount
3086	  of symbols than C so to allow projections.
3087
3088endif # TEST_KALLSYMS
3089
3090config TEST_DEBUG_VIRTUAL
3091	tristate "Test CONFIG_DEBUG_VIRTUAL feature"
3092	depends on DEBUG_VIRTUAL
3093	help
3094	  Test the kernel's ability to detect incorrect calls to
3095	  virt_to_phys() done against the non-linear part of the
3096	  kernel's virtual address map.
3097
3098	  If unsure, say N.
3099
3100config TEST_MEMCAT_P
3101	tristate "Test memcat_p() helper function"
3102	help
3103	  Test the memcat_p() helper for correctly merging two
3104	  pointer arrays together.
3105
3106	  If unsure, say N.
3107
3108config TEST_OBJAGG
3109	tristate "Perform selftest on object aggreration manager"
3110	default n
3111	depends on OBJAGG
3112	help
3113	  Enable this option to test object aggregation manager on boot
3114	  (or module load).
3115
3116config TEST_MEMINIT
3117	tristate "Test heap/page initialization"
3118	help
3119	  Test if the kernel is zero-initializing heap and page allocations.
3120	  This can be useful to test init_on_alloc and init_on_free features.
3121
3122	  If unsure, say N.
3123
3124config TEST_HMM
3125	tristate "Test HMM (Heterogeneous Memory Management)"
3126	depends on TRANSPARENT_HUGEPAGE
3127	depends on DEVICE_PRIVATE
3128	select HMM_MIRROR
3129	select MMU_NOTIFIER
3130	help
3131	  This is a pseudo device driver solely for testing HMM.
3132	  Say M here if you want to build the HMM test module.
3133	  Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
3134
3135	  If unsure, say N.
3136
3137config TEST_FREE_PAGES
3138	tristate "Test freeing pages"
3139	help
3140	  Test that a memory leak does not occur due to a race between
3141	  freeing a block of pages and a speculative page reference.
3142	  Loading this module is safe if your kernel has the bug fixed.
3143	  If the bug is not fixed, it will leak gigabytes of memory and
3144	  probably OOM your system.
3145
3146config TEST_FPU
3147	tristate "Test floating point operations in kernel space"
3148	depends on ARCH_HAS_KERNEL_FPU_SUPPORT && !KCOV_INSTRUMENT_ALL
3149	help
3150	  Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
3151	  which will trigger a sequence of floating point operations. This is used
3152	  for self-testing floating point control register setting in
3153	  kernel_fpu_begin().
3154
3155	  If unsure, say N.
3156
3157config TEST_CLOCKSOURCE_WATCHDOG
3158	tristate "Test clocksource watchdog in kernel space"
3159	depends on CLOCKSOURCE_WATCHDOG
3160	help
3161	  Enable this option to create a kernel module that will trigger
3162	  a test of the clocksource watchdog.  This module may be loaded
3163	  via modprobe or insmod in which case it will run upon being
3164	  loaded, or it may be built in, in which case it will run
3165	  shortly after boot.
3166
3167	  If unsure, say N.
3168
3169config TEST_OBJPOOL
3170	tristate "Test module for correctness and stress of objpool"
3171	default n
3172	depends on m && DEBUG_KERNEL
3173	help
3174	  This builds the "test_objpool" module that should be used for
3175	  correctness verification and concurrent testings of objects
3176	  allocation and reclamation.
3177
3178	  If unsure, say N.
3179
3180config INT_POW_TEST
3181	tristate "Integer exponentiation (int_pow) test" if !KUNIT_ALL_TESTS
3182	depends on KUNIT
3183	default KUNIT_ALL_TESTS
3184	help
3185	  This option enables the KUnit test suite for the int_pow function,
3186	  which performs integer exponentiation. The test suite is designed to
3187	  verify that the implementation of int_pow correctly computes the power
3188	  of a given base raised to a given exponent.
3189
3190	  Enabling this option will include tests that check various scenarios
3191	  and edge cases to ensure the accuracy and reliability of the exponentiation
3192	  function.
3193
3194	  If unsure, say N
3195
3196config INT_SQRT_KUNIT_TEST
3197	tristate "Integer square root test" if !KUNIT_ALL_TESTS
3198	depends on KUNIT
3199	default KUNIT_ALL_TESTS
3200	help
3201	  This option enables the KUnit test suite for the int_sqrt() function,
3202	  which performs square root calculation. The test suite checks
3203	  various scenarios, including edge cases, to ensure correctness.
3204
3205	  Enabling this option will include tests that check various scenarios
3206	  and edge cases to ensure the accuracy and reliability of the square root
3207	  function.
3208
3209	  If unsure, say N
3210
3211endif # RUNTIME_TESTING_MENU
3212
3213config ARCH_USE_MEMTEST
3214	bool
3215	help
3216	  An architecture should select this when it uses early_memtest()
3217	  during boot process.
3218
3219config MEMTEST
3220	bool "Memtest"
3221	depends on ARCH_USE_MEMTEST
3222	help
3223	  This option adds a kernel parameter 'memtest', which allows memtest
3224	  to be set and executed.
3225	        memtest=0, mean disabled; -- default
3226	        memtest=1, mean do 1 test pattern;
3227	        ...
3228	        memtest=17, mean do 17 test patterns.
3229	  If you are unsure how to answer this question, answer N.
3230
3231
3232
3233config HYPERV_TESTING
3234	bool "Microsoft Hyper-V driver testing"
3235	default n
3236	depends on HYPERV && DEBUG_FS
3237	help
3238	  Select this option to enable Hyper-V vmbus testing.
3239
3240endmenu # "Kernel Testing and Coverage"
3241
3242menu "Rust hacking"
3243
3244config RUST_DEBUG_ASSERTIONS
3245	bool "Debug assertions"
3246	depends on RUST
3247	help
3248	  Enables rustc's `-Cdebug-assertions` codegen option.
3249
3250	  This flag lets you turn `cfg(debug_assertions)` conditional
3251	  compilation on or off. This can be used to enable extra debugging
3252	  code in development but not in production. For example, it controls
3253	  the behavior of the standard library's `debug_assert!` macro.
3254
3255	  Note that this will apply to all Rust code, including `core`.
3256
3257	  If unsure, say N.
3258
3259config RUST_OVERFLOW_CHECKS
3260	bool "Overflow checks"
3261	default y
3262	depends on RUST
3263	help
3264	  Enables rustc's `-Coverflow-checks` codegen option.
3265
3266	  This flag allows you to control the behavior of runtime integer
3267	  overflow. When overflow-checks are enabled, a Rust panic will occur
3268	  on overflow.
3269
3270	  Note that this will apply to all Rust code, including `core`.
3271
3272	  If unsure, say Y.
3273
3274config RUST_BUILD_ASSERT_ALLOW
3275	bool "Allow unoptimized build-time assertions"
3276	depends on RUST
3277	help
3278	  Controls how `build_error!` and `build_assert!` are handled during the build.
3279
3280	  If calls to them exist in the binary, it may indicate a violated invariant
3281	  or that the optimizer failed to verify the invariant during compilation.
3282
3283	  This should not happen, thus by default the build is aborted. However,
3284	  as an escape hatch, you can choose Y here to ignore them during build
3285	  and let the check be carried at runtime (with `panic!` being called if
3286	  the check fails).
3287
3288	  If unsure, say N.
3289
3290config RUST_KERNEL_DOCTESTS
3291	bool "Doctests for the `kernel` crate" if !KUNIT_ALL_TESTS
3292	depends on RUST && KUNIT=y
3293	default KUNIT_ALL_TESTS
3294	help
3295	  This builds the documentation tests of the `kernel` crate
3296	  as KUnit tests.
3297
3298	  For more information on KUnit and unit tests in general,
3299	  please refer to the KUnit documentation in Documentation/dev-tools/kunit/.
3300
3301	  If unsure, say N.
3302
3303endmenu # "Rust"
3304
3305endmenu # Kernel hacking
3306