linux - lib/Kconfig.debug

3432 lines · 112.1 KiB

1	# SPDX-License-Identifier: GPL-2.0-only
2	menu "Kernel hacking"
3
4	menu "printk and dmesg options"
5
6	config 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
21	config 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
38	config 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
49	config 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
64	config 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
75	config 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
90	config 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
108	config 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
180	config 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
191	config 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
200	config 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
209	endmenu # "printk and dmesg options"
210
211	config 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
217	config 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
225	menu "Compile-time checks and compiler options"
226
227	config 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
237	config AS_HAS_NON_CONST_ULEB128
238	def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:)
239
240	choice
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
253	config 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
259	config 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 \|\| (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
271	config 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
283	config 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
301	endchoice # "Debug information"
302
303	if DEBUG_INFO
304
305	config 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
317	choice
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
325	config DEBUG_INFO_COMPRESSED_NONE
326	bool "Don't compress debug information"
327	help
328	Don't compress debug info sections.
329
330	config DEBUG_INFO_COMPRESSED_ZLIB
331	bool "Compress debugging information with zlib"
332	depends on $(cc-option,-gz=zlib)
333	depends on $(ld-option,--compress-debug-sections=zlib)
334	help
335	Compress the debug information using zlib. Requires GCC 5.0+ or Clang
336	5.0+, binutils 2.26+, and zlib.
337
338	Users of dpkg-deb via debian/rules may find an increase in
339	size of their debug .deb packages with this config set, due to the
340	debug info being compressed with zlib, then the object files being
341	recompressed with a different compression scheme. But this is still
342	preferable to setting KDEB_COMPRESS or DPKG_DEB_COMPRESSOR_TYPE to
343	"none" which would be even larger.
344
345	config 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
355	endchoice # "Compressed Debug information"
356
357	config 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
377	config 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
392	config PAHOLE_HAS_SPLIT_BTF
393	def_bool PAHOLE_VERSION >= 119
394
395	config 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
403	config 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
412	config 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
419	config 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
429	config 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
439	endif # DEBUG_INFO
440
441	config 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
456	config 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
464	config 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
474	config HEADERS_INSTALL
475	bool "Install uapi headers to usr/include"
476	help
477	This option will install uapi headers (headers exported to user-space)
478	into the usr/include directory for use during the kernel build.
479	This is unneeded for building the kernel itself, but needed for some
480	user-space program samples. It is also needed by some features such
481	as uapi header sanity checks.
482
483	config DEBUG_SECTION_MISMATCH
484	bool "Enable full Section mismatch analysis"
485	depends on CC_IS_GCC
486	help
487	The section mismatch analysis checks if there are illegal
488	references from one section to another section.
489	During linktime or runtime, some sections are dropped;
490	any use of code/data previously in these sections would
491	most likely result in an oops.
492	In the code, functions and variables are annotated with
493	__init,, etc. (see the full list in include/linux/init.h),
494	which results in the code/data being placed in specific sections.
495	The section mismatch analysis is always performed after a full
496	kernel build, and enabling this option causes the following
497	additional step to occur:
498	- Add the option -fno-inline-functions-called-once to gcc commands.
499	When inlining a function annotated with __init in a non-init
500	function, we would lose the section information and thus
501	the analysis would not catch the illegal reference.
502	This option tells gcc to inline less (but it does result in
503	a larger kernel).
504
505	config SECTION_MISMATCH_WARN_ONLY
506	bool "Make section mismatch errors non-fatal"
507	default y
508	help
509	If you say N here, the build process will fail if there are any
510	section mismatch, instead of just throwing warnings.
511
512	If unsure, say Y.
513
514	config DEBUG_FORCE_FUNCTION_ALIGN_64B
515	bool "Force all function address 64B aligned"
516	depends on EXPERT && (X86_64 \|\| ARM64 \|\| PPC32 \|\| PPC64 \|\| ARC \|\| RISCV \|\| S390)
517	select FUNCTION_ALIGNMENT_64B
518	help
519	There are cases that a commit from one domain changes the function
520	address alignment of other domains, and cause magic performance
521	bump (regression or improvement). Enable this option will help to
522	verify if the bump is caused by function alignment changes, while
523	it will slightly increase the kernel size and affect icache usage.
524
525	It is mainly for debug and performance tuning use.
526
527	#
528	# Select this config option from the architecture Kconfig, if it
529	# is preferred to always offer frame pointers as a config
530	# option on the architecture (regardless of KERNEL_DEBUG):
531	#
532	config ARCH_WANT_FRAME_POINTERS
533	bool
534
535	config FRAME_POINTER
536	bool "Compile the kernel with frame pointers"
537	depends on DEBUG_KERNEL && (M68K \|\| UML \|\| SUPERH) \|\| ARCH_WANT_FRAME_POINTERS
538	default y if (DEBUG_INFO && UML) \|\| ARCH_WANT_FRAME_POINTERS
539	help
540	If you say Y here the resulting kernel image will be slightly
541	larger and slower, but it gives very useful debugging information
542	in case of kernel bugs. (precise oopses/stacktraces/warnings)
543
544	config OBJTOOL
545	bool
546
547	config OBJTOOL_WERROR
548	bool "Upgrade objtool warnings to errors"
549	depends on OBJTOOL && !COMPILE_TEST
550	help
551	Fail the build on objtool warnings.
552
553	Objtool warnings can indicate kernel instability, including boot
554	failures. This option is highly recommended.
555
556	If unsure, say Y.
557
558	config STACK_VALIDATION
559	bool "Compile-time stack metadata validation"
560	depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
561	select OBJTOOL
562	default n
563	help
564	Validate frame pointer rules at compile-time. This helps ensure that
565	runtime stack traces are more reliable.
566
567	For more information, see
568	tools/objtool/Documentation/objtool.txt.
569
570	config NOINSTR_VALIDATION
571	bool
572	depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
573	select OBJTOOL
574	default y
575
576	config VMLINUX_MAP
577	bool "Generate vmlinux.map file when linking"
578	depends on EXPERT
579	help
580	Selecting this option will pass "-Map=vmlinux.map" to ld
581	when linking vmlinux. That file can be useful for verifying
582	and debugging magic section games, and for seeing which
583	pieces of code get eliminated with
584	CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
585
586	config BUILTIN_MODULE_RANGES
587	bool "Generate address range information for builtin modules"
588	depends on !LTO
589	depends on VMLINUX_MAP
590	help
591	When modules are built into the kernel, there will be no module name
592	associated with its symbols in /proc/kallsyms. Tracers may want to
593	identify symbols by module name and symbol name regardless of whether
594	the module is configured as loadable or not.
595
596	This option generates modules.builtin.ranges in the build tree with
597	offset ranges (per ELF section) for the module(s) they belong to.
598	It also records an anchor symbol to determine the load address of the
599	section.
600
601	config DEBUG_FORCE_WEAK_PER_CPU
602	bool "Force weak per-cpu definitions"
603	depends on DEBUG_KERNEL
604	help
605	s390 and alpha require percpu variables in modules to be
606	defined weak to work around addressing range issue which
607	puts the following two restrictions on percpu variable
608	definitions.
609
610	1. percpu symbols must be unique whether static or not
611	2. percpu variables can't be defined inside a function
612
613	To ensure that generic code follows the above rules, this
614	option forces all percpu variables to be defined as weak.
615
616	endmenu # "Compiler options"
617
618	menu "Generic Kernel Debugging Instruments"
619
620	config MAGIC_SYSRQ
621	bool "Magic SysRq key"
622	depends on !UML
623	help
624	If you say Y here, you will have some control over the system even
625	if the system crashes for example during kernel debugging (e.g., you
626	will be able to flush the buffer cache to disk, reboot the system
627	immediately or dump some status information). This is accomplished
628	by pressing various keys while holding SysRq (Alt+PrintScreen). It
629	also works on a serial console (on PC hardware at least), if you
630	send a BREAK and then within 5 seconds a command keypress. The
631	keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
632	Don't say Y unless you really know what this hack does.
633
634	config MAGIC_SYSRQ_DEFAULT_ENABLE
635	hex "Enable magic SysRq key functions by default"
636	depends on MAGIC_SYSRQ
637	default 0x1
638	help
639	Specifies which SysRq key functions are enabled by default.
640	This may be set to 1 or 0 to enable or disable them all, or
641	to a bitmask as described in Documentation/admin-guide/sysrq.rst.
642
643	config MAGIC_SYSRQ_SERIAL
644	bool "Enable magic SysRq key over serial"
645	depends on MAGIC_SYSRQ
646	default y
647	help
648	Many embedded boards have a disconnected TTL level serial which can
649	generate some garbage that can lead to spurious false sysrq detects.
650	This option allows you to decide whether you want to enable the
651	magic SysRq key.
652
653	config MAGIC_SYSRQ_SERIAL_SEQUENCE
654	string "Char sequence that enables magic SysRq over serial"
655	depends on MAGIC_SYSRQ_SERIAL
656	default ""
657	help
658	Specifies a sequence of characters that can follow BREAK to enable
659	SysRq on a serial console.
660
661	If unsure, leave an empty string and the option will not be enabled.
662
663	config DEBUG_FS
664	bool "Debug Filesystem"
665	help
666	debugfs is a virtual file system that kernel developers use to put
667	debugging files into. Enable this option to be able to read and
668	write to these files.
669
670	For detailed documentation on the debugfs API, see
671	Documentation/filesystems/.
672
673	If unsure, say N.
674
675	choice
676	prompt "Debugfs default access"
677	depends on DEBUG_FS
678	default DEBUG_FS_ALLOW_ALL
679	help
680	This selects the default access restrictions for debugfs.
681	It can be overridden with kernel command line option
682	debugfs=[on,no-mount,off]. The restrictions apply for API access
683	and filesystem registration.
684
685	config DEBUG_FS_ALLOW_ALL
686	bool "Access normal"
687	help
688	No restrictions apply. Both API and filesystem registration
689	is on. This is the normal default operation.
690
691	config DEBUG_FS_DISALLOW_MOUNT
692	bool "Do not register debugfs as filesystem"
693	help
694	The API is open but filesystem is not loaded. Clients can still do
695	their work and read with debug tools that do not need
696	debugfs filesystem.
697
698	config DEBUG_FS_ALLOW_NONE
699	bool "No access"
700	help
701	Access is off. Clients get -PERM when trying to create nodes in
702	debugfs tree and debugfs is not registered as a filesystem.
703	Client can then back-off or continue without debugfs access.
704
705	endchoice
706
707	source "lib/Kconfig.kgdb"
708	source "lib/Kconfig.ubsan"
709	source "lib/Kconfig.kcsan"
710
711	endmenu
712
713	menu "Networking Debugging"
714
715	source "net/Kconfig.debug"
716
717	endmenu # "Networking Debugging"
718
719	menu "Memory Debugging"
720
721	source "mm/Kconfig.debug"
722
723	config DEBUG_OBJECTS
724	bool "Debug object operations"
725	depends on DEBUG_KERNEL
726	help
727	If you say Y here, additional code will be inserted into the
728	kernel to track the life time of various objects and validate
729	the operations on those objects.
730
731	config DEBUG_OBJECTS_SELFTEST
732	bool "Debug objects selftest"
733	depends on DEBUG_OBJECTS
734	help
735	This enables the selftest of the object debug code.
736
737	config DEBUG_OBJECTS_FREE
738	bool "Debug objects in freed memory"
739	depends on DEBUG_OBJECTS
740	help
741	This enables checks whether a k/v free operation frees an area
742	which contains an object which has not been deactivated
743	properly. This can make kmalloc/kfree-intensive workloads
744	much slower.
745
746	config DEBUG_OBJECTS_TIMERS
747	bool "Debug timer objects"
748	depends on DEBUG_OBJECTS
749	help
750	If you say Y here, additional code will be inserted into the
751	timer routines to track the life time of timer objects and
752	validate the timer operations.
753
754	config DEBUG_OBJECTS_WORK
755	bool "Debug work objects"
756	depends on DEBUG_OBJECTS
757	help
758	If you say Y here, additional code will be inserted into the
759	work queue routines to track the life time of work objects and
760	validate the work operations.
761
762	config DEBUG_OBJECTS_RCU_HEAD
763	bool "Debug RCU callbacks objects"
764	depends on DEBUG_OBJECTS
765	help
766	Enable this to turn on debugging of RCU list heads (call_rcu() usage).
767
768	config DEBUG_OBJECTS_PERCPU_COUNTER
769	bool "Debug percpu counter objects"
770	depends on DEBUG_OBJECTS
771	help
772	If you say Y here, additional code will be inserted into the
773	percpu counter routines to track the life time of percpu counter
774	objects and validate the percpu counter operations.
775
776	config DEBUG_OBJECTS_ENABLE_DEFAULT
777	int "debug_objects bootup default value (0-1)"
778	range 0 1
779	default "1"
780	depends on DEBUG_OBJECTS
781	help
782	Debug objects boot parameter default value
783
784	config SHRINKER_DEBUG
785	bool "Enable shrinker debugging support"
786	depends on DEBUG_FS
787	help
788	Say Y to enable the shrinker debugfs interface which provides
789	visibility into the kernel memory shrinkers subsystem.
790	Disable it to avoid an extra memory footprint.
791
792	config DEBUG_STACK_USAGE
793	bool "Stack utilization instrumentation"
794	depends on DEBUG_KERNEL
795	help
796	Enables the display of the minimum amount of free stack which each
797	task has ever had available in the sysrq-T and sysrq-P debug output.
798	Also emits a message to dmesg when a process exits if that process
799	used more stack space than previously exiting processes.
800
801	This option will slow down process creation somewhat.
802
803	config SCHED_STACK_END_CHECK
804	bool "Detect stack corruption on calls to schedule()"
805	depends on DEBUG_KERNEL
806	default n
807	help
808	This option checks for a stack overrun on calls to schedule().
809	If the stack end location is found to be over written always panic as
810	the content of the corrupted region can no longer be trusted.
811	This is to ensure no erroneous behaviour occurs which could result in
812	data corruption or a sporadic crash at a later stage once the region
813	is examined. The runtime overhead introduced is minimal.
814
815	config ARCH_HAS_DEBUG_VM_PGTABLE
816	bool
817	help
818	An architecture should select this when it can successfully
819	build and run DEBUG_VM_PGTABLE.
820
821	config DEBUG_VFS
822	bool "Debug VFS"
823	depends on DEBUG_KERNEL
824	help
825	Enable this to turn on extended checks in the VFS layer that may impact
826	performance.
827
828	If unsure, say N.
829
830	config DEBUG_VM_IRQSOFF
831	def_bool DEBUG_VM && !PREEMPT_RT
832
833	config DEBUG_VM
834	bool "Debug VM"
835	depends on DEBUG_KERNEL
836	help
837	Enable this to turn on extended checks in the virtual-memory system
838	that may impact performance.
839
840	If unsure, say N.
841
842	config DEBUG_VM_SHOOT_LAZIES
843	bool "Debug MMU_LAZY_TLB_SHOOTDOWN implementation"
844	depends on DEBUG_VM
845	depends on MMU_LAZY_TLB_SHOOTDOWN
846	help
847	Enable additional IPIs that ensure lazy tlb mm references are removed
848	before the mm is freed.
849
850	If unsure, say N.
851
852	config DEBUG_VM_MAPLE_TREE
853	bool "Debug VM maple trees"
854	depends on DEBUG_VM
855	select DEBUG_MAPLE_TREE
856	help
857	Enable VM maple tree debugging information and extra validations.
858
859	If unsure, say N.
860
861	config DEBUG_VM_RB
862	bool "Debug VM red-black trees"
863	depends on DEBUG_VM
864	help
865	Enable VM red-black tree debugging information and extra validations.
866
867	If unsure, say N.
868
869	config DEBUG_VM_PGFLAGS
870	bool "Debug page-flags operations"
871	depends on DEBUG_VM
872	help
873	Enables extra validation on page flags operations.
874
875	If unsure, say N.
876
877	config DEBUG_VM_PGTABLE
878	bool "Debug arch page table for semantics compliance"
879	depends on MMU
880	depends on ARCH_HAS_DEBUG_VM_PGTABLE
881	default y if DEBUG_VM
882	help
883	This option provides a debug method which can be used to test
884	architecture page table helper functions on various platforms in
885	verifying if they comply with expected generic MM semantics. This
886	will help architecture code in making sure that any changes or
887	new additions of these helpers still conform to expected
888	semantics of the generic MM. Platforms will have to opt in for
889	this through ARCH_HAS_DEBUG_VM_PGTABLE.
890
891	If unsure, say N.
892
893	config ARCH_HAS_DEBUG_VIRTUAL
894	bool
895
896	config DEBUG_VIRTUAL
897	bool "Debug VM translations"
898	depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
899	help
900	Enable some costly sanity checks in virtual to page code. This can
901	catch mistakes with virt_to_page() and friends.
902
903	If unsure, say N.
904
905	config DEBUG_NOMMU_REGIONS
906	bool "Debug the global anon/private NOMMU mapping region tree"
907	depends on DEBUG_KERNEL && !MMU
908	help
909	This option causes the global tree of anonymous and private mapping
910	regions to be regularly checked for invalid topology.
911
912	config DEBUG_MEMORY_INIT
913	bool "Debug memory initialisation" if EXPERT
914	default !EXPERT
915	help
916	Enable this for additional checks during memory initialisation.
917	The sanity checks verify aspects of the VM such as the memory model
918	and other information provided by the architecture. Verbose
919	information will be printed at KERN_DEBUG loglevel depending
920	on the mminit_loglevel= command-line option.
921
922	If unsure, say Y
923
924	config MEMORY_NOTIFIER_ERROR_INJECT
925	tristate "Memory hotplug notifier error injection module"
926	depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
927	help
928	This option provides the ability to inject artificial errors to
929	memory hotplug notifier chain callbacks. It is controlled through
930	debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
931
932	If the notifier call chain should be failed with some events
933	notified, write the error code to "actions/<notifier event>/error".
934
935	Example: Inject memory hotplug offline error (-12 == -ENOMEM)
936
937	# cd /sys/kernel/debug/notifier-error-inject/memory
938	# echo -12 > actions/MEM_GOING_OFFLINE/error
939	# echo offline > /sys/devices/system/memory/memoryXXX/state
940	bash: echo: write error: Cannot allocate memory
941
942	To compile this code as a module, choose M here: the module will
943	be called memory-notifier-error-inject.
944
945	If unsure, say N.
946
947	config DEBUG_PER_CPU_MAPS
948	bool "Debug access to per_cpu maps"
949	depends on DEBUG_KERNEL
950	depends on SMP
951	help
952	Say Y to verify that the per_cpu map being accessed has
953	been set up. This adds a fair amount of code to kernel memory
954	and decreases performance.
955
956	Say N if unsure.
957
958	config DEBUG_KMAP_LOCAL
959	bool "Debug kmap_local temporary mappings"
960	depends on DEBUG_KERNEL && KMAP_LOCAL
961	help
962	This option enables additional error checking for the kmap_local
963	infrastructure. Disable for production use.
964
965	config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
966	bool
967
968	config DEBUG_KMAP_LOCAL_FORCE_MAP
969	bool "Enforce kmap_local temporary mappings"
970	depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
971	select KMAP_LOCAL
972	select DEBUG_KMAP_LOCAL
973	help
974	This option enforces temporary mappings through the kmap_local
975	mechanism for non-highmem pages and on non-highmem systems.
976	Disable this for production systems!
977
978	config DEBUG_HIGHMEM
979	bool "Highmem debugging"
980	depends on DEBUG_KERNEL && HIGHMEM
981	select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
982	select DEBUG_KMAP_LOCAL
983	help
984	This option enables additional error checking for high memory
985	systems. Disable for production systems.
986
987	config HAVE_DEBUG_STACKOVERFLOW
988	bool
989
990	config DEBUG_STACKOVERFLOW
991	bool "Check for stack overflows"
992	depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
993	help
994	Say Y here if you want to check for overflows of kernel, IRQ
995	and exception stacks (if your architecture uses them). This
996	option will show detailed messages if free stack space drops
997	below a certain limit.
998
999	These kinds of bugs usually occur when call-chains in the
1000	kernel get too deep, especially when interrupts are
1001	involved.
1002
1003	Use this in cases where you see apparently random memory
1004	corruption, especially if it appears in 'struct thread_info'
1005
1006	If in doubt, say "N".
1007
1008	config CODE_TAGGING
1009	bool
1010	select KALLSYMS
1011
1012	config MEM_ALLOC_PROFILING
1013	bool "Enable memory allocation profiling"
1014	default n
1015	depends on MMU
1016	depends on PROC_FS
1017	depends on !DEBUG_FORCE_WEAK_PER_CPU
1018	select CODE_TAGGING
1019	select PAGE_EXTENSION
1020	select SLAB_OBJ_EXT
1021	help
1022	Track allocation source code and record total allocation size
1023	initiated at that code location. The mechanism can be used to track
1024	memory leaks with a low performance and memory impact.
1025
1026	config MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
1027	bool "Enable memory allocation profiling by default"
1028	default y
1029	depends on MEM_ALLOC_PROFILING
1030
1031	config MEM_ALLOC_PROFILING_DEBUG
1032	bool "Memory allocation profiler debugging"
1033	default n
1034	depends on MEM_ALLOC_PROFILING
1035	select MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
1036	help
1037	Adds warnings with helpful error messages for memory allocation
1038	profiling.
1039
1040	source "lib/Kconfig.kasan"
1041	source "lib/Kconfig.kfence"
1042	source "lib/Kconfig.kmsan"
1043
1044	endmenu # "Memory Debugging"
1045
1046	config DEBUG_SHIRQ
1047	bool "Debug shared IRQ handlers"
1048	depends on DEBUG_KERNEL
1049	help
1050	Enable this to generate a spurious interrupt just before a shared
1051	interrupt handler is deregistered (generating one when registering
1052	is currently disabled). Drivers need to handle this correctly. Some
1053	don't and need to be caught.
1054
1055	menu "Debug Oops, Lockups and Hangs"
1056
1057	config PANIC_ON_OOPS
1058	bool "Panic on Oops"
1059	help
1060	Say Y here to enable the kernel to panic when it oopses. This
1061	has the same effect as setting oops=panic on the kernel command
1062	line.
1063
1064	This feature is useful to ensure that the kernel does not do
1065	anything erroneous after an oops which could result in data
1066	corruption or other issues.
1067
1068	Say N if unsure.
1069
1070	config PANIC_TIMEOUT
1071	int "panic timeout"
1072	default 0
1073	help
1074	Set the timeout value (in seconds) until a reboot occurs when
1075	the kernel panics. If n = 0, then we wait forever. A timeout
1076	value n > 0 will wait n seconds before rebooting, while a timeout
1077	value n < 0 will reboot immediately. This setting can be overridden
1078	with the kernel command line option panic=, and from userspace via
1079	/proc/sys/kernel/panic.
1080
1081	config LOCKUP_DETECTOR
1082	bool
1083
1084	config SOFTLOCKUP_DETECTOR
1085	bool "Detect Soft Lockups"
1086	depends on DEBUG_KERNEL && !S390
1087	select LOCKUP_DETECTOR
1088	help
1089	Say Y here to enable the kernel to act as a watchdog to detect
1090	soft lockups.
1091
1092	Softlockups are bugs that cause the kernel to loop in kernel
1093	mode for more than 20 seconds, without giving other tasks a
1094	chance to run. The current stack trace is displayed upon
1095	detection and the system will stay locked up.
1096
1097	config SOFTLOCKUP_DETECTOR_INTR_STORM
1098	bool "Detect Interrupt Storm in Soft Lockups"
1099	depends on SOFTLOCKUP_DETECTOR && IRQ_TIME_ACCOUNTING
1100	select GENERIC_IRQ_STAT_SNAPSHOT
1101	default y if NR_CPUS <= 128
1102	help
1103	Say Y here to enable the kernel to detect interrupt storm
1104	during "soft lockups".
1105
1106	"soft lockups" can be caused by a variety of reasons. If one is
1107	caused by an interrupt storm, then the storming interrupts will not
1108	be on the callstack. To detect this case, it is necessary to report
1109	the CPU stats and the interrupt counts during the "soft lockups".
1110
1111	config BOOTPARAM_SOFTLOCKUP_PANIC
1112	bool "Panic (Reboot) On Soft Lockups"
1113	depends on SOFTLOCKUP_DETECTOR
1114	help
1115	Say Y here to enable the kernel to panic on "soft lockups",
1116	which are bugs that cause the kernel to loop in kernel
1117	mode for more than 20 seconds (configurable using the watchdog_thresh
1118	sysctl), without giving other tasks a chance to run.
1119
1120	The panic can be used in combination with panic_timeout,
1121	to cause the system to reboot automatically after a
1122	lockup has been detected. This feature is useful for
1123	high-availability systems that have uptime guarantees and
1124	where a lockup must be resolved ASAP.
1125
1126	Say N if unsure.
1127
1128	config HAVE_HARDLOCKUP_DETECTOR_BUDDY
1129	bool
1130	depends on SMP
1131	default y
1132
1133	#
1134	# Global switch whether to build a hardlockup detector at all. It is available
1135	# only when the architecture supports at least one implementation. There are
1136	# two exceptions. The hardlockup detector is never enabled on:
1137	#
1138	# s390: it reported many false positives there
1139	#
1140	# sparc64: has a custom implementation which is not using the common
1141	# hardlockup command line options and sysctl interface.
1142	#
1143	config HARDLOCKUP_DETECTOR
1144	bool "Detect Hard Lockups"
1145	depends on DEBUG_KERNEL && !S390 && !HARDLOCKUP_DETECTOR_SPARC64
1146	depends on HAVE_HARDLOCKUP_DETECTOR_PERF \|\| HAVE_HARDLOCKUP_DETECTOR_BUDDY \|\| HAVE_HARDLOCKUP_DETECTOR_ARCH
1147	imply HARDLOCKUP_DETECTOR_PERF
1148	imply HARDLOCKUP_DETECTOR_BUDDY
1149	imply HARDLOCKUP_DETECTOR_ARCH
1150	select LOCKUP_DETECTOR
1151
1152	help
1153	Say Y here to enable the kernel to act as a watchdog to detect
1154	hard lockups.
1155
1156	Hardlockups are bugs that cause the CPU to loop in kernel mode
1157	for more than 10 seconds, without letting other interrupts have a
1158	chance to run. The current stack trace is displayed upon detection
1159	and the system will stay locked up.
1160
1161	#
1162	# Note that arch-specific variants are always preferred.
1163	#
1164	config HARDLOCKUP_DETECTOR_PREFER_BUDDY
1165	bool "Prefer the buddy CPU hardlockup detector"
1166	depends on HARDLOCKUP_DETECTOR
1167	depends on HAVE_HARDLOCKUP_DETECTOR_PERF && HAVE_HARDLOCKUP_DETECTOR_BUDDY
1168	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1169	help
1170	Say Y here to prefer the buddy hardlockup detector over the perf one.
1171
1172	With the buddy detector, each CPU uses its softlockup hrtimer
1173	to check that the next CPU is processing hrtimer interrupts by
1174	verifying that a counter is increasing.
1175
1176	This hardlockup detector is useful on systems that don't have
1177	an arch-specific hardlockup detector or if resources needed
1178	for the hardlockup detector are better used for other things.
1179
1180	config HARDLOCKUP_DETECTOR_PERF
1181	bool
1182	depends on HARDLOCKUP_DETECTOR
1183	depends on HAVE_HARDLOCKUP_DETECTOR_PERF && !HARDLOCKUP_DETECTOR_PREFER_BUDDY
1184	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1185	select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1186
1187	config HARDLOCKUP_DETECTOR_BUDDY
1188	bool
1189	depends on HARDLOCKUP_DETECTOR
1190	depends on HAVE_HARDLOCKUP_DETECTOR_BUDDY
1191	depends on !HAVE_HARDLOCKUP_DETECTOR_PERF \|\| HARDLOCKUP_DETECTOR_PREFER_BUDDY
1192	depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1193	select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1194
1195	config HARDLOCKUP_DETECTOR_ARCH
1196	bool
1197	depends on HARDLOCKUP_DETECTOR
1198	depends on HAVE_HARDLOCKUP_DETECTOR_ARCH
1199	help
1200	The arch-specific implementation of the hardlockup detector will
1201	be used.
1202
1203	#
1204	# Both the "perf" and "buddy" hardlockup detectors count hrtimer
1205	# interrupts. This config enables functions managing this common code.
1206	#
1207	config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1208	bool
1209	select SOFTLOCKUP_DETECTOR
1210
1211	#
1212	# Enables a timestamp based low pass filter to compensate for perf based
1213	# hard lockup detection which runs too fast due to turbo modes.
1214	#
1215	config HARDLOCKUP_CHECK_TIMESTAMP
1216	bool
1217
1218	config BOOTPARAM_HARDLOCKUP_PANIC
1219	bool "Panic (Reboot) On Hard Lockups"
1220	depends on HARDLOCKUP_DETECTOR
1221	help
1222	Say Y here to enable the kernel to panic on "hard lockups",
1223	which are bugs that cause the kernel to loop in kernel
1224	mode with interrupts disabled for more than 10 seconds (configurable
1225	using the watchdog_thresh sysctl).
1226
1227	Say N if unsure.
1228
1229	config DETECT_HUNG_TASK
1230	bool "Detect Hung Tasks"
1231	depends on DEBUG_KERNEL
1232	default SOFTLOCKUP_DETECTOR
1233	help
1234	Say Y here to enable the kernel to detect "hung tasks",
1235	which are bugs that cause the task to be stuck in
1236	uninterruptible "D" state indefinitely.
1237
1238	When a hung task is detected, the kernel will print the
1239	current stack trace (which you should report), but the
1240	task will stay in uninterruptible state. If lockdep is
1241	enabled then all held locks will also be reported. This
1242	feature has negligible overhead.
1243
1244	config DEFAULT_HUNG_TASK_TIMEOUT
1245	int "Default timeout for hung task detection (in seconds)"
1246	depends on DETECT_HUNG_TASK
1247	default 120
1248	help
1249	This option controls the default timeout (in seconds) used
1250	to determine when a task has become non-responsive and should
1251	be considered hung.
1252
1253	It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1254	sysctl or by writing a value to
1255	/proc/sys/kernel/hung_task_timeout_secs.
1256
1257	A timeout of 0 disables the check. The default is two minutes.
1258	Keeping the default should be fine in most cases.
1259
1260	config BOOTPARAM_HUNG_TASK_PANIC
1261	bool "Panic (Reboot) On Hung Tasks"
1262	depends on DETECT_HUNG_TASK
1263	help
1264	Say Y here to enable the kernel to panic on "hung tasks",
1265	which are bugs that cause the kernel to leave a task stuck
1266	in uninterruptible "D" state.
1267
1268	The panic can be used in combination with panic_timeout,
1269	to cause the system to reboot automatically after a
1270	hung task has been detected. This feature is useful for
1271	high-availability systems that have uptime guarantees and
1272	where a hung tasks must be resolved ASAP.
1273
1274	Say N if unsure.
1275
1276	config DETECT_HUNG_TASK_BLOCKER
1277	bool "Dump Hung Tasks Blocker"
1278	depends on DETECT_HUNG_TASK
1279	depends on !PREEMPT_RT
1280	default y
1281	help
1282	Say Y here to show the blocker task's stacktrace who acquires
1283	the mutex lock which "hung tasks" are waiting.
1284	This will add overhead a bit but shows suspicious tasks and
1285	call trace if it comes from waiting a mutex.
1286
1287	config WQ_WATCHDOG
1288	bool "Detect Workqueue Stalls"
1289	depends on DEBUG_KERNEL
1290	help
1291	Say Y here to enable stall detection on workqueues. If a
1292	worker pool doesn't make forward progress on a pending work
1293	item for over a given amount of time, 30s by default, a
1294	warning message is printed along with dump of workqueue
1295	state. This can be configured through kernel parameter
1296	"workqueue.watchdog_thresh" and its sysfs counterpart.
1297
1298	config WQ_CPU_INTENSIVE_REPORT
1299	bool "Report per-cpu work items which hog CPU for too long"
1300	depends on DEBUG_KERNEL
1301	help
1302	Say Y here to enable reporting of concurrency-managed per-cpu work
1303	items that hog CPUs for longer than
1304	workqueue.cpu_intensive_thresh_us. Workqueue automatically
1305	detects and excludes them from concurrency management to prevent
1306	them from stalling other per-cpu work items. Occassional
1307	triggering may not necessarily indicate a problem. Repeated
1308	triggering likely indicates that the work item should be switched
1309	to use an unbound workqueue.
1310
1311	config TEST_LOCKUP
1312	tristate "Test module to generate lockups"
1313	depends on m
1314	help
1315	This builds the "test_lockup" module that helps to make sure
1316	that watchdogs and lockup detectors are working properly.
1317
1318	Depending on module parameters it could emulate soft or hard
1319	lockup, "hung task", or locking arbitrary lock for a long time.
1320	Also it could generate series of lockups with cooling-down periods.
1321
1322	If unsure, say N.
1323
1324	endmenu # "Debug lockups and hangs"
1325
1326	menu "Scheduler Debugging"
1327
1328	config SCHED_INFO
1329	bool
1330	default n
1331
1332	config SCHEDSTATS
1333	bool "Collect scheduler statistics"
1334	depends on PROC_FS
1335	select SCHED_INFO
1336	help
1337	If you say Y here, additional code will be inserted into the
1338	scheduler and related routines to collect statistics about
1339	scheduler behavior and provide them in /proc/schedstat. These
1340	stats may be useful for both tuning and debugging the scheduler
1341	If you aren't debugging the scheduler or trying to tune a specific
1342	application, you can say N to avoid the very slight overhead
1343	this adds.
1344
1345	endmenu
1346
1347	config DEBUG_PREEMPT
1348	bool "Debug preemptible kernel"
1349	depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1350	help
1351	If you say Y here then the kernel will use a debug variant of the
1352	commonly used smp_processor_id() function and will print warnings
1353	if kernel code uses it in a preemption-unsafe way. Also, the kernel
1354	will detect preemption count underflows.
1355
1356	This option has potential to introduce high runtime overhead,
1357	depending on workload as it triggers debugging routines for each
1358	this_cpu operation. It should only be used for debugging purposes.
1359
1360	menu "Lock Debugging (spinlocks, mutexes, etc...)"
1361
1362	config LOCK_DEBUGGING_SUPPORT
1363	bool
1364	depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1365	default y
1366
1367	config PROVE_LOCKING
1368	bool "Lock debugging: prove locking correctness"
1369	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1370	select LOCKDEP
1371	select DEBUG_SPINLOCK
1372	select DEBUG_MUTEXES if !PREEMPT_RT
1373	select DEBUG_RT_MUTEXES if RT_MUTEXES
1374	select DEBUG_RWSEMS if !PREEMPT_RT
1375	select DEBUG_WW_MUTEX_SLOWPATH
1376	select DEBUG_LOCK_ALLOC
1377	select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1378	select TRACE_IRQFLAGS
1379	default n
1380	help
1381	This feature enables the kernel to prove that all locking
1382	that occurs in the kernel runtime is mathematically
1383	correct: that under no circumstance could an arbitrary (and
1384	not yet triggered) combination of observed locking
1385	sequences (on an arbitrary number of CPUs, running an
1386	arbitrary number of tasks and interrupt contexts) cause a
1387	deadlock.
1388
1389	In short, this feature enables the kernel to report locking
1390	related deadlocks before they actually occur.
1391
1392	The proof does not depend on how hard and complex a
1393	deadlock scenario would be to trigger: how many
1394	participant CPUs, tasks and irq-contexts would be needed
1395	for it to trigger. The proof also does not depend on
1396	timing: if a race and a resulting deadlock is possible
1397	theoretically (no matter how unlikely the race scenario
1398	is), it will be proven so and will immediately be
1399	reported by the kernel (once the event is observed that
1400	makes the deadlock theoretically possible).
1401
1402	If a deadlock is impossible (i.e. the locking rules, as
1403	observed by the kernel, are mathematically correct), the
1404	kernel reports nothing.
1405
1406	NOTE: this feature can also be enabled for rwlocks, mutexes
1407	and rwsems - in which case all dependencies between these
1408	different locking variants are observed and mapped too, and
1409	the proof of observed correctness is also maintained for an
1410	arbitrary combination of these separate locking variants.
1411
1412	For more details, see Documentation/locking/lockdep-design.rst.
1413
1414	config PROVE_RAW_LOCK_NESTING
1415	bool "Enable raw_spinlock - spinlock nesting checks" if !ARCH_SUPPORTS_RT
1416	depends on PROVE_LOCKING
1417	default y if ARCH_SUPPORTS_RT
1418	help
1419	Enable the raw_spinlock vs. spinlock nesting checks which ensure
1420	that the lock nesting rules for PREEMPT_RT enabled kernels are
1421	not violated.
1422
1423	config LOCK_STAT
1424	bool "Lock usage statistics"
1425	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1426	select LOCKDEP
1427	select DEBUG_SPINLOCK
1428	select DEBUG_MUTEXES if !PREEMPT_RT
1429	select DEBUG_RT_MUTEXES if RT_MUTEXES
1430	select DEBUG_LOCK_ALLOC
1431	default n
1432	help
1433	This feature enables tracking lock contention points
1434
1435	For more details, see Documentation/locking/lockstat.rst
1436
1437	This also enables lock events required by "perf lock",
1438	subcommand of perf.
1439	If you want to use "perf lock", you also need to turn on
1440	CONFIG_EVENT_TRACING.
1441
1442	CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1443	(CONFIG_LOCKDEP defines "acquire" and "release" events.)
1444
1445	config DEBUG_RT_MUTEXES
1446	bool "RT Mutex debugging, deadlock detection"
1447	depends on DEBUG_KERNEL && RT_MUTEXES
1448	help
1449	This allows rt mutex semantics violations and rt mutex related
1450	deadlocks (lockups) to be detected and reported automatically.
1451
1452	config DEBUG_SPINLOCK
1453	bool "Spinlock and rw-lock debugging: basic checks"
1454	depends on DEBUG_KERNEL
1455	select UNINLINE_SPIN_UNLOCK
1456	help
1457	Say Y here and build SMP to catch missing spinlock initialization
1458	and certain other kinds of spinlock errors commonly made. This is
1459	best used in conjunction with the NMI watchdog so that spinlock
1460	deadlocks are also debuggable.
1461
1462	config DEBUG_MUTEXES
1463	bool "Mutex debugging: basic checks"
1464	depends on DEBUG_KERNEL && !PREEMPT_RT
1465	help
1466	This feature allows mutex semantics violations to be detected and
1467	reported.
1468
1469	config DEBUG_WW_MUTEX_SLOWPATH
1470	bool "Wait/wound mutex debugging: Slowpath testing"
1471	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1472	select DEBUG_LOCK_ALLOC
1473	select DEBUG_SPINLOCK
1474	select DEBUG_MUTEXES if !PREEMPT_RT
1475	select DEBUG_RT_MUTEXES if PREEMPT_RT
1476	help
1477	This feature enables slowpath testing for w/w mutex users by
1478	injecting additional -EDEADLK wound/backoff cases. Together with
1479	the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1480	will test all possible w/w mutex interface abuse with the
1481	exception of simply not acquiring all the required locks.
1482	Note that this feature can introduce significant overhead, so
1483	it really should not be enabled in a production or distro kernel,
1484	even a debug kernel. If you are a driver writer, enable it. If
1485	you are a distro, do not.
1486
1487	config DEBUG_RWSEMS
1488	bool "RW Semaphore debugging: basic checks"
1489	depends on DEBUG_KERNEL && !PREEMPT_RT
1490	help
1491	This debugging feature allows mismatched rw semaphore locks
1492	and unlocks to be detected and reported.
1493
1494	config DEBUG_LOCK_ALLOC
1495	bool "Lock debugging: detect incorrect freeing of live locks"
1496	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1497	select DEBUG_SPINLOCK
1498	select DEBUG_MUTEXES if !PREEMPT_RT
1499	select DEBUG_RT_MUTEXES if RT_MUTEXES
1500	select LOCKDEP
1501	help
1502	This feature will check whether any held lock (spinlock, rwlock,
1503	mutex or rwsem) is incorrectly freed by the kernel, via any of the
1504	memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1505	vfree(), etc.), whether a live lock is incorrectly reinitialized via
1506	spin_lock_init()/mutex_init()/etc., or whether there is any lock
1507	held during task exit.
1508
1509	config LOCKDEP
1510	bool
1511	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1512	select STACKTRACE
1513	select KALLSYMS
1514	select KALLSYMS_ALL
1515
1516	config LOCKDEP_SMALL
1517	bool
1518
1519	config LOCKDEP_BITS
1520	int "Size for MAX_LOCKDEP_ENTRIES (as Nth power of 2)"
1521	depends on LOCKDEP && !LOCKDEP_SMALL
1522	range 10 24
1523	default 15
1524	help
1525	Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1526
1527	config LOCKDEP_CHAINS_BITS
1528	int "Size for MAX_LOCKDEP_CHAINS (as Nth power of 2)"
1529	depends on LOCKDEP && !LOCKDEP_SMALL
1530	range 10 21
1531	default 16
1532	help
1533	Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1534
1535	config LOCKDEP_STACK_TRACE_BITS
1536	int "Size for MAX_STACK_TRACE_ENTRIES (as Nth power of 2)"
1537	depends on LOCKDEP && !LOCKDEP_SMALL
1538	range 10 26
1539	default 19
1540	help
1541	Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1542
1543	config LOCKDEP_STACK_TRACE_HASH_BITS
1544	int "Size for STACK_TRACE_HASH_SIZE (as Nth power of 2)"
1545	depends on LOCKDEP && !LOCKDEP_SMALL
1546	range 10 26
1547	default 14
1548	help
1549	Try increasing this value if you need large STACK_TRACE_HASH_SIZE.
1550
1551	config LOCKDEP_CIRCULAR_QUEUE_BITS
1552	int "Size for elements in circular_queue struct (as Nth power of 2)"
1553	depends on LOCKDEP
1554	range 10 26
1555	default 12
1556	help
1557	Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1558
1559	config DEBUG_LOCKDEP
1560	bool "Lock dependency engine debugging"
1561	depends on DEBUG_KERNEL && LOCKDEP
1562	select DEBUG_IRQFLAGS
1563	help
1564	If you say Y here, the lock dependency engine will do
1565	additional runtime checks to debug itself, at the price
1566	of more runtime overhead.
1567
1568	config DEBUG_ATOMIC_SLEEP
1569	bool "Sleep inside atomic section checking"
1570	select PREEMPT_COUNT
1571	depends on DEBUG_KERNEL
1572	depends on !ARCH_NO_PREEMPT
1573	help
1574	If you say Y here, various routines which may sleep will become very
1575	noisy if they are called inside atomic sections: when a spinlock is
1576	held, inside an rcu read side critical section, inside preempt disabled
1577	sections, inside an interrupt, etc...
1578
1579	config DEBUG_LOCKING_API_SELFTESTS
1580	bool "Locking API boot-time self-tests"
1581	depends on DEBUG_KERNEL
1582	help
1583	Say Y here if you want the kernel to run a short self-test during
1584	bootup. The self-test checks whether common types of locking bugs
1585	are detected by debugging mechanisms or not. (if you disable
1586	lock debugging then those bugs won't be detected of course.)
1587	The following locking APIs are covered: spinlocks, rwlocks,
1588	mutexes and rwsems.
1589
1590	config LOCK_TORTURE_TEST
1591	tristate "torture tests for locking"
1592	depends on DEBUG_KERNEL
1593	select TORTURE_TEST
1594	help
1595	This option provides a kernel module that runs torture tests
1596	on kernel locking primitives. The kernel module may be built
1597	after the fact on the running kernel to be tested, if desired.
1598
1599	Say Y here if you want kernel locking-primitive torture tests
1600	to be built into the kernel.
1601	Say M if you want these torture tests to build as a module.
1602	Say N if you are unsure.
1603
1604	config WW_MUTEX_SELFTEST
1605	tristate "Wait/wound mutex selftests"
1606	help
1607	This option provides a kernel module that runs tests on the
1608	on the struct ww_mutex locking API.
1609
1610	It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1611	with this test harness.
1612
1613	Say M if you want these self tests to build as a module.
1614	Say N if you are unsure.
1615
1616	config SCF_TORTURE_TEST
1617	tristate "torture tests for smp_call_function*()"
1618	depends on DEBUG_KERNEL
1619	select TORTURE_TEST
1620	help
1621	This option provides a kernel module that runs torture tests
1622	on the smp_call_function() family of primitives. The kernel
1623	module may be built after the fact on the running kernel to
1624	be tested, if desired.
1625
1626	config CSD_LOCK_WAIT_DEBUG
1627	bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1628	depends on DEBUG_KERNEL
1629	depends on SMP
1630	depends on 64BIT
1631	default n
1632	help
1633	This option enables debug prints when CPUs are slow to respond
1634	to the smp_call_function*() IPI wrappers. These debug prints
1635	include the IPI handler function currently executing (if any)
1636	and relevant stack traces.
1637
1638	config CSD_LOCK_WAIT_DEBUG_DEFAULT
1639	bool "Default csd_lock_wait() debugging on at boot time"
1640	depends on CSD_LOCK_WAIT_DEBUG
1641	depends on 64BIT
1642	default n
1643	help
1644	This option causes the csdlock_debug= kernel boot parameter to
1645	default to 1 (basic debugging) instead of 0 (no debugging).
1646
1647	endmenu # lock debugging
1648
1649	config TRACE_IRQFLAGS
1650	depends on TRACE_IRQFLAGS_SUPPORT
1651	bool
1652	help
1653	Enables hooks to interrupt enabling and disabling for
1654	either tracing or lock debugging.
1655
1656	config TRACE_IRQFLAGS_NMI
1657	def_bool y
1658	depends on TRACE_IRQFLAGS
1659	depends on TRACE_IRQFLAGS_NMI_SUPPORT
1660
1661	config NMI_CHECK_CPU
1662	bool "Debugging for CPUs failing to respond to backtrace requests"
1663	depends on DEBUG_KERNEL
1664	depends on X86
1665	default n
1666	help
1667	Enables debug prints when a CPU fails to respond to a given
1668	backtrace NMI. These prints provide some reasons why a CPU
1669	might legitimately be failing to respond, for example, if it
1670	is offline of if ignore_nmis is set.
1671
1672	config DEBUG_IRQFLAGS
1673	bool "Debug IRQ flag manipulation"
1674	help
1675	Enables checks for potentially unsafe enabling or disabling of
1676	interrupts, such as calling raw_local_irq_restore() when interrupts
1677	are enabled.
1678
1679	config STACKTRACE
1680	bool "Stack backtrace support"
1681	depends on STACKTRACE_SUPPORT
1682	help
1683	This option causes the kernel to create a /proc/pid/stack for
1684	every process, showing its current stack trace.
1685	It is also used by various kernel debugging features that require
1686	stack trace generation.
1687
1688	config WARN_ALL_UNSEEDED_RANDOM
1689	bool "Warn for all uses of unseeded randomness"
1690	default n
1691	help
1692	Some parts of the kernel contain bugs relating to their use of
1693	cryptographically secure random numbers before it's actually possible
1694	to generate those numbers securely. This setting ensures that these
1695	flaws don't go unnoticed, by enabling a message, should this ever
1696	occur. This will allow people with obscure setups to know when things
1697	are going wrong, so that they might contact developers about fixing
1698	it.
1699
1700	Unfortunately, on some models of some architectures getting
1701	a fully seeded CRNG is extremely difficult, and so this can
1702	result in dmesg getting spammed for a surprisingly long
1703	time. This is really bad from a security perspective, and
1704	so architecture maintainers really need to do what they can
1705	to get the CRNG seeded sooner after the system is booted.
1706	However, since users cannot do anything actionable to
1707	address this, by default this option is disabled.
1708
1709	Say Y here if you want to receive warnings for all uses of
1710	unseeded randomness. This will be of use primarily for
1711	those developers interested in improving the security of
1712	Linux kernels running on their architecture (or
1713	subarchitecture).
1714
1715	config DEBUG_KOBJECT
1716	bool "kobject debugging"
1717	depends on DEBUG_KERNEL
1718	help
1719	If you say Y here, some extra kobject debugging messages will be sent
1720	to the syslog.
1721
1722	config DEBUG_KOBJECT_RELEASE
1723	bool "kobject release debugging"
1724	depends on DEBUG_OBJECTS_TIMERS
1725	help
1726	kobjects are reference counted objects. This means that their
1727	last reference count put is not predictable, and the kobject can
1728	live on past the point at which a driver decides to drop its
1729	initial reference to the kobject gained on allocation. An
1730	example of this would be a struct device which has just been
1731	unregistered.
1732
1733	However, some buggy drivers assume that after such an operation,
1734	the memory backing the kobject can be immediately freed. This
1735	goes completely against the principles of a refcounted object.
1736
1737	If you say Y here, the kernel will delay the release of kobjects
1738	on the last reference count to improve the visibility of this
1739	kind of kobject release bug.
1740
1741	config HAVE_DEBUG_BUGVERBOSE
1742	bool
1743
1744	menu "Debug kernel data structures"
1745
1746	config DEBUG_LIST
1747	bool "Debug linked list manipulation"
1748	depends on DEBUG_KERNEL
1749	select LIST_HARDENED
1750	help
1751	Enable this to turn on extended checks in the linked-list walking
1752	routines.
1753
1754	This option trades better quality error reports for performance, and
1755	is more suitable for kernel debugging. If you care about performance,
1756	you should only enable CONFIG_LIST_HARDENED instead.
1757
1758	If unsure, say N.
1759
1760	config DEBUG_PLIST
1761	bool "Debug priority linked list manipulation"
1762	depends on DEBUG_KERNEL
1763	help
1764	Enable this to turn on extended checks in the priority-ordered
1765	linked-list (plist) walking routines. This checks the entire
1766	list multiple times during each manipulation.
1767
1768	If unsure, say N.
1769
1770	config DEBUG_SG
1771	bool "Debug SG table operations"
1772	depends on DEBUG_KERNEL
1773	help
1774	Enable this to turn on checks on scatter-gather tables. This can
1775	help find problems with drivers that do not properly initialize
1776	their sg tables.
1777
1778	If unsure, say N.
1779
1780	config DEBUG_NOTIFIERS
1781	bool "Debug notifier call chains"
1782	depends on DEBUG_KERNEL
1783	help
1784	Enable this to turn on sanity checking for notifier call chains.
1785	This is most useful for kernel developers to make sure that
1786	modules properly unregister themselves from notifier chains.
1787	This is a relatively cheap check but if you care about maximum
1788	performance, say N.
1789
1790	config DEBUG_CLOSURES
1791	bool "Debug closures (bcache async widgits)"
1792	depends on CLOSURES
1793	select DEBUG_FS
1794	help
1795	Keeps all active closures in a linked list and provides a debugfs
1796	interface to list them, which makes it possible to see asynchronous
1797	operations that get stuck.
1798
1799	config DEBUG_MAPLE_TREE
1800	bool "Debug maple trees"
1801	depends on DEBUG_KERNEL
1802	help
1803	Enable maple tree debugging information and extra validations.
1804
1805	If unsure, say N.
1806
1807	endmenu
1808
1809	source "kernel/rcu/Kconfig.debug"
1810
1811	config DEBUG_WQ_FORCE_RR_CPU
1812	bool "Force round-robin CPU selection for unbound work items"
1813	depends on DEBUG_KERNEL
1814	default n
1815	help
1816	Workqueue used to implicitly guarantee that work items queued
1817	without explicit CPU specified are put on the local CPU. This
1818	guarantee is no longer true and while local CPU is still
1819	preferred work items may be put on foreign CPUs. Kernel
1820	parameter "workqueue.debug_force_rr_cpu" is added to force
1821	round-robin CPU selection to flush out usages which depend on the
1822	now broken guarantee. This config option enables the debug
1823	feature by default. When enabled, memory and cache locality will
1824	be impacted.
1825
1826	config CPU_HOTPLUG_STATE_CONTROL
1827	bool "Enable CPU hotplug state control"
1828	depends on DEBUG_KERNEL
1829	depends on HOTPLUG_CPU
1830	default n
1831	help
1832	Allows to write steps between "offline" and "online" to the CPUs
1833	sysfs target file so states can be stepped granular. This is a debug
1834	option for now as the hotplug machinery cannot be stopped and
1835	restarted at arbitrary points yet.
1836
1837	Say N if your are unsure.
1838
1839	config LATENCYTOP
1840	bool "Latency measuring infrastructure"
1841	depends on DEBUG_KERNEL
1842	depends on STACKTRACE_SUPPORT
1843	depends on PROC_FS
1844	depends on FRAME_POINTER \|\| MIPS \|\| PPC \|\| S390 \|\| MICROBLAZE \|\| ARM \|\| ARC \|\| X86
1845	select KALLSYMS
1846	select KALLSYMS_ALL
1847	select STACKTRACE
1848	select SCHEDSTATS
1849	help
1850	Enable this option if you want to use the LatencyTOP tool
1851	to find out which userspace is blocking on what kernel operations.
1852
1853	config DEBUG_CGROUP_REF
1854	bool "Disable inlining of cgroup css reference count functions"
1855	depends on DEBUG_KERNEL
1856	depends on CGROUPS
1857	depends on KPROBES
1858	default n
1859	help
1860	Force cgroup css reference count functions to not be inlined so
1861	that they can be kprobed for debugging.
1862
1863	source "kernel/trace/Kconfig"
1864
1865	config PROVIDE_OHCI1394_DMA_INIT
1866	bool "Remote debugging over FireWire early on boot"
1867	depends on PCI && X86
1868	help
1869	If you want to debug problems which hang or crash the kernel early
1870	on boot and the crashing machine has a FireWire port, you can use
1871	this feature to remotely access the memory of the crashed machine
1872	over FireWire. This employs remote DMA as part of the OHCI1394
1873	specification which is now the standard for FireWire controllers.
1874
1875	With remote DMA, you can monitor the printk buffer remotely using
1876	firescope and access all memory below 4GB using fireproxy from gdb.
1877	Even controlling a kernel debugger is possible using remote DMA.
1878
1879	Usage:
1880
1881	If ohci1394_dma=early is used as boot parameter, it will initialize
1882	all OHCI1394 controllers which are found in the PCI config space.
1883
1884	As all changes to the FireWire bus such as enabling and disabling
1885	devices cause a bus reset and thereby disable remote DMA for all
1886	devices, be sure to have the cable plugged and FireWire enabled on
1887	the debugging host before booting the debug target for debugging.
1888
1889	This code (~1k) is freed after boot. By then, the firewire stack
1890	in charge of the OHCI-1394 controllers should be used instead.
1891
1892	See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1893
1894	source "samples/Kconfig"
1895
1896	config ARCH_HAS_DEVMEM_IS_ALLOWED
1897	bool
1898
1899	config STRICT_DEVMEM
1900	bool "Filter access to /dev/mem"
1901	depends on MMU && DEVMEM
1902	depends on ARCH_HAS_DEVMEM_IS_ALLOWED \|\| GENERIC_LIB_DEVMEM_IS_ALLOWED
1903	default y if PPC \|\| X86 \|\| ARM64 \|\| S390
1904	help
1905	If this option is disabled, you allow userspace (root) access to all
1906	of memory, including kernel and userspace memory. Accidental
1907	access to this is obviously disastrous, but specific access can
1908	be used by people debugging the kernel. Note that with PAT support
1909	enabled, even in this case there are restrictions on /dev/mem
1910	use due to the cache aliasing requirements.
1911
1912	If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1913	file only allows userspace access to PCI space and the BIOS code and
1914	data regions. This is sufficient for dosemu and X and all common
1915	users of /dev/mem.
1916
1917	If in doubt, say Y.
1918
1919	config IO_STRICT_DEVMEM
1920	bool "Filter I/O access to /dev/mem"
1921	depends on STRICT_DEVMEM
1922	help
1923	If this option is disabled, you allow userspace (root) access to all
1924	io-memory regardless of whether a driver is actively using that
1925	range. Accidental access to this is obviously disastrous, but
1926	specific access can be used by people debugging kernel drivers.
1927
1928	If this option is switched on, the /dev/mem file only allows
1929	userspace access to idle io-memory ranges (see /proc/iomem) This
1930	may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1931	if the driver using a given range cannot be disabled.
1932
1933	If in doubt, say Y.
1934
1935	menu "$(SRCARCH) Debugging"
1936
1937	source "arch/$(SRCARCH)/Kconfig.debug"
1938
1939	endmenu
1940
1941	menu "Kernel Testing and Coverage"
1942
1943	source "lib/kunit/Kconfig"
1944
1945	config NOTIFIER_ERROR_INJECTION
1946	tristate "Notifier error injection"
1947	depends on DEBUG_KERNEL
1948	select DEBUG_FS
1949	help
1950	This option provides the ability to inject artificial errors to
1951	specified notifier chain callbacks. It is useful to test the error
1952	handling of notifier call chain failures.
1953
1954	Say N if unsure.
1955
1956	config PM_NOTIFIER_ERROR_INJECT
1957	tristate "PM notifier error injection module"
1958	depends on PM && NOTIFIER_ERROR_INJECTION
1959	default m if PM_DEBUG
1960	help
1961	This option provides the ability to inject artificial errors to
1962	PM notifier chain callbacks. It is controlled through debugfs
1963	interface /sys/kernel/debug/notifier-error-inject/pm
1964
1965	If the notifier call chain should be failed with some events
1966	notified, write the error code to "actions/<notifier event>/error".
1967
1968	Example: Inject PM suspend error (-12 = -ENOMEM)
1969
1970	# cd /sys/kernel/debug/notifier-error-inject/pm/
1971	# echo -12 > actions/PM_SUSPEND_PREPARE/error
1972	# echo mem > /sys/power/state
1973	bash: echo: write error: Cannot allocate memory
1974
1975	To compile this code as a module, choose M here: the module will
1976	be called pm-notifier-error-inject.
1977
1978	If unsure, say N.
1979
1980	config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1981	tristate "OF reconfig notifier error injection module"
1982	depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1983	help
1984	This option provides the ability to inject artificial errors to
1985	OF reconfig notifier chain callbacks. It is controlled
1986	through debugfs interface under
1987	/sys/kernel/debug/notifier-error-inject/OF-reconfig/
1988
1989	If the notifier call chain should be failed with some events
1990	notified, write the error code to "actions/<notifier event>/error".
1991
1992	To compile this code as a module, choose M here: the module will
1993	be called of-reconfig-notifier-error-inject.
1994
1995	If unsure, say N.
1996
1997	config NETDEV_NOTIFIER_ERROR_INJECT
1998	tristate "Netdev notifier error injection module"
1999	depends on NET && NOTIFIER_ERROR_INJECTION
2000	help
2001	This option provides the ability to inject artificial errors to
2002	netdevice notifier chain callbacks. It is controlled through debugfs
2003	interface /sys/kernel/debug/notifier-error-inject/netdev
2004
2005	If the notifier call chain should be failed with some events
2006	notified, write the error code to "actions/<notifier event>/error".
2007
2008	Example: Inject netdevice mtu change error (-22 = -EINVAL)
2009
2010	# cd /sys/kernel/debug/notifier-error-inject/netdev
2011	# echo -22 > actions/NETDEV_CHANGEMTU/error
2012	# ip link set eth0 mtu 1024
2013	RTNETLINK answers: Invalid argument
2014
2015	To compile this code as a module, choose M here: the module will
2016	be called netdev-notifier-error-inject.
2017
2018	If unsure, say N.
2019
2020	config FUNCTION_ERROR_INJECTION
2021	bool "Fault-injections of functions"
2022	depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
2023	help
2024	Add fault injections into various functions that are annotated with
2025	ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
2026	value of these functions. This is useful to test error paths of code.
2027
2028	If unsure, say N
2029
2030	config FAULT_INJECTION
2031	bool "Fault-injection framework"
2032	depends on DEBUG_KERNEL
2033	help
2034	Provide fault-injection framework.
2035	For more details, see Documentation/fault-injection/.
2036
2037	config FAILSLAB
2038	bool "Fault-injection capability for kmalloc"
2039	depends on FAULT_INJECTION
2040	help
2041	Provide fault-injection capability for kmalloc.
2042
2043	config FAIL_PAGE_ALLOC
2044	bool "Fault-injection capability for alloc_pages()"
2045	depends on FAULT_INJECTION
2046	help
2047	Provide fault-injection capability for alloc_pages().
2048
2049	config FAULT_INJECTION_USERCOPY
2050	bool "Fault injection capability for usercopy functions"
2051	depends on FAULT_INJECTION
2052	help
2053	Provides fault-injection capability to inject failures
2054	in usercopy functions (copy_from_user(), get_user(), ...).
2055
2056	config FAIL_MAKE_REQUEST
2057	bool "Fault-injection capability for disk IO"
2058	depends on FAULT_INJECTION && BLOCK
2059	help
2060	Provide fault-injection capability for disk IO.
2061
2062	config FAIL_IO_TIMEOUT
2063	bool "Fault-injection capability for faking disk interrupts"
2064	depends on FAULT_INJECTION && BLOCK
2065	help
2066	Provide fault-injection capability on end IO handling. This
2067	will make the block layer "forget" an interrupt as configured,
2068	thus exercising the error handling.
2069
2070	Only works with drivers that use the generic timeout handling,
2071	for others it won't do anything.
2072
2073	config FAIL_FUTEX
2074	bool "Fault-injection capability for futexes"
2075	select DEBUG_FS
2076	depends on FAULT_INJECTION && FUTEX
2077	help
2078	Provide fault-injection capability for futexes.
2079
2080	config FAULT_INJECTION_DEBUG_FS
2081	bool "Debugfs entries for fault-injection capabilities"
2082	depends on FAULT_INJECTION && SYSFS && DEBUG_FS
2083	help
2084	Enable configuration of fault-injection capabilities via debugfs.
2085
2086	config FAIL_FUNCTION
2087	bool "Fault-injection capability for functions"
2088	depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
2089	help
2090	Provide function-based fault-injection capability.
2091	This will allow you to override a specific function with a return
2092	with given return value. As a result, function caller will see
2093	an error value and have to handle it. This is useful to test the
2094	error handling in various subsystems.
2095
2096	config FAIL_MMC_REQUEST
2097	bool "Fault-injection capability for MMC IO"
2098	depends on FAULT_INJECTION_DEBUG_FS && MMC
2099	help
2100	Provide fault-injection capability for MMC IO.
2101	This will make the mmc core return data errors. This is
2102	useful to test the error handling in the mmc block device
2103	and to test how the mmc host driver handles retries from
2104	the block device.
2105
2106	config FAIL_SUNRPC
2107	bool "Fault-injection capability for SunRPC"
2108	depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2109	help
2110	Provide fault-injection capability for SunRPC and
2111	its consumers.
2112
2113	config FAIL_SKB_REALLOC
2114	bool "Fault-injection capability forcing skb to reallocate"
2115	depends on FAULT_INJECTION_DEBUG_FS
2116	help
2117	Provide fault-injection capability that forces the skb to be
2118	reallocated, catching possible invalid pointers to the skb.
2119
2120	For more information, check
2121	Documentation/fault-injection/fault-injection.rst
2122
2123	config FAULT_INJECTION_CONFIGFS
2124	bool "Configfs interface for fault-injection capabilities"
2125	depends on FAULT_INJECTION
2126	select CONFIGFS_FS
2127	help
2128	This option allows configfs-based drivers to dynamically configure
2129	fault-injection via configfs. Each parameter for driver-specific
2130	fault-injection can be made visible as a configfs attribute in a
2131	configfs group.
2132
2133
2134	config FAULT_INJECTION_STACKTRACE_FILTER
2135	bool "stacktrace filter for fault-injection capabilities"
2136	depends on FAULT_INJECTION
2137	depends on (FAULT_INJECTION_DEBUG_FS \|\| FAULT_INJECTION_CONFIGFS) && STACKTRACE_SUPPORT
2138	select STACKTRACE
2139	depends on FRAME_POINTER \|\| MIPS \|\| PPC \|\| S390 \|\| MICROBLAZE \|\| ARM \|\| ARC \|\| X86
2140	help
2141	Provide stacktrace filter for fault-injection capabilities
2142
2143	config ARCH_HAS_KCOV
2144	bool
2145	help
2146	An architecture should select this when it can successfully
2147	build and run with CONFIG_KCOV. This typically requires
2148	disabling instrumentation for some early boot code.
2149
2150	config KCOV
2151	bool "Code coverage for fuzzing"
2152	depends on ARCH_HAS_KCOV
2153	depends on !ARCH_WANTS_NO_INSTR \|\| HAVE_NOINSTR_HACK \|\| \
2154	GCC_VERSION >= 120000 \|\| CC_IS_CLANG
2155	select DEBUG_FS
2156	select OBJTOOL if HAVE_NOINSTR_HACK
2157	help
2158	KCOV exposes kernel code coverage information in a form suitable
2159	for coverage-guided fuzzing (randomized testing).
2160
2161	For more details, see Documentation/dev-tools/kcov.rst.
2162
2163	config KCOV_ENABLE_COMPARISONS
2164	bool "Enable comparison operands collection by KCOV"
2165	depends on KCOV
2166	depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2167	help
2168	KCOV also exposes operands of every comparison in the instrumented
2169	code along with operand sizes and PCs of the comparison instructions.
2170	These operands can be used by fuzzing engines to improve the quality
2171	of fuzzing coverage.
2172
2173	config KCOV_INSTRUMENT_ALL
2174	bool "Instrument all code by default"
2175	depends on KCOV
2176	default y
2177	help
2178	If you are doing generic system call fuzzing (like e.g. syzkaller),
2179	then you will want to instrument the whole kernel and you should
2180	say y here. If you are doing more targeted fuzzing (like e.g.
2181	filesystem fuzzing with AFL) then you will want to enable coverage
2182	for more specific subsets of files, and should say n here.
2183
2184	config KCOV_IRQ_AREA_SIZE
2185	hex "Size of interrupt coverage collection area in words"
2186	depends on KCOV
2187	default 0x40000
2188	help
2189	KCOV uses preallocated per-cpu areas to collect coverage from
2190	soft interrupts. This specifies the size of those areas in the
2191	number of unsigned long words.
2192
2193	config KCOV_SELFTEST
2194	bool "Perform short selftests on boot"
2195	depends on KCOV
2196	help
2197	Run short KCOV coverage collection selftests on boot.
2198	On test failure, causes the kernel to panic. Recommended to be
2199	enabled, ensuring critical functionality works as intended.
2200
2201	menuconfig RUNTIME_TESTING_MENU
2202	bool "Runtime Testing"
2203	default y
2204
2205	if RUNTIME_TESTING_MENU
2206
2207	config TEST_DHRY
2208	tristate "Dhrystone benchmark test"
2209	help
2210	Enable this to include the Dhrystone 2.1 benchmark. This test
2211	calculates the number of Dhrystones per second, and the number of
2212	DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided
2213	by 1757 (the number of Dhrystones per second obtained on the VAX
2214	11/780, nominally a 1 MIPS machine).
2215
2216	To run the benchmark, it needs to be enabled explicitly, either from
2217	the kernel command line (when built-in), or from userspace (when
2218	built-in or modular).
2219
2220	Run once during kernel boot:
2221
2222	test_dhry.run
2223
2224	Set number of iterations from kernel command line:
2225
2226	test_dhry.iterations=<n>
2227
2228	Set number of iterations from userspace:
2229
2230	echo <n> > /sys/module/test_dhry/parameters/iterations
2231
2232	Trigger manual run from userspace:
2233
2234	echo y > /sys/module/test_dhry/parameters/run
2235
2236	If the number of iterations is <= 0, the test will devise a suitable
2237	number of iterations (test runs for at least 2s) automatically.
2238	This process takes ca. 4s.
2239
2240	If unsure, say N.
2241
2242	config LKDTM
2243	tristate "Linux Kernel Dump Test Tool Module"
2244	depends on DEBUG_FS
2245	help
2246	This module enables testing of the different dumping mechanisms by
2247	inducing system failures at predefined crash points.
2248	If you don't need it: say N
2249	Choose M here to compile this code as a module. The module will be
2250	called lkdtm.
2251
2252	Documentation on how to use the module can be found in
2253	Documentation/fault-injection/provoke-crashes.rst
2254
2255	config CPUMASK_KUNIT_TEST
2256	tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2257	depends on KUNIT
2258	default KUNIT_ALL_TESTS
2259	help
2260	Enable to turn on cpumask tests, running at boot or module load time.
2261
2262	For more information on KUnit and unit tests in general, please refer
2263	to the KUnit documentation in Documentation/dev-tools/kunit/.
2264
2265	If unsure, say N.
2266
2267	config TEST_LIST_SORT
2268	tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2269	depends on KUNIT
2270	default KUNIT_ALL_TESTS
2271	help
2272	Enable this to turn on 'list_sort()' function test. This test is
2273	executed only once during system boot (so affects only boot time),
2274	or at module load time.
2275
2276	If unsure, say N.
2277
2278	config TEST_MIN_HEAP
2279	tristate "Min heap test"
2280	depends on DEBUG_KERNEL \|\| m
2281	help
2282	Enable this to turn on min heap function tests. This test is
2283	executed only once during system boot (so affects only boot time),
2284	or at module load time.
2285
2286	If unsure, say N.
2287
2288	config TEST_SORT
2289	tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2290	depends on KUNIT
2291	default KUNIT_ALL_TESTS
2292	help
2293	This option enables the self-test function of 'sort()' at boot,
2294	or at module load time.
2295
2296	If unsure, say N.
2297
2298	config TEST_DIV64
2299	tristate "64bit/32bit division and modulo test"
2300	depends on DEBUG_KERNEL \|\| m
2301	help
2302	Enable this to turn on 'do_div()' function test. This test is
2303	executed only once during system boot (so affects only boot time),
2304	or at module load time.
2305
2306	If unsure, say N.
2307
2308	config TEST_MULDIV64
2309	tristate "mul_u64_u64_div_u64() test"
2310	depends on DEBUG_KERNEL \|\| m
2311	help
2312	Enable this to turn on 'mul_u64_u64_div_u64()' function test.
2313	This test is executed only once during system boot (so affects
2314	only boot time), or at module load time.
2315
2316	If unsure, say N.
2317
2318	config TEST_IOV_ITER
2319	tristate "Test iov_iter operation" if !KUNIT_ALL_TESTS
2320	depends on KUNIT
2321	depends on MMU
2322	default KUNIT_ALL_TESTS
2323	help
2324	Enable this to turn on testing of the operation of the I/O iterator
2325	(iov_iter). This test is executed only once during system boot (so
2326	affects only boot time), or at module load time.
2327
2328	If unsure, say N.
2329
2330	config KPROBES_SANITY_TEST
2331	tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2332	depends on DEBUG_KERNEL
2333	depends on KPROBES
2334	depends on KUNIT
2335	select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2336	default KUNIT_ALL_TESTS
2337	help
2338	This option provides for testing basic kprobes functionality on
2339	boot. Samples of kprobe and kretprobe are inserted and
2340	verified for functionality.
2341
2342	Say N if you are unsure.
2343
2344	config FPROBE_SANITY_TEST
2345	bool "Self test for fprobe"
2346	depends on DEBUG_KERNEL
2347	depends on FPROBE
2348	depends on KUNIT=y
2349	help
2350	This option will enable testing the fprobe when the system boot.
2351	A series of tests are made to verify that the fprobe is functioning
2352	properly.
2353
2354	Say N if you are unsure.
2355
2356	config BACKTRACE_SELF_TEST
2357	tristate "Self test for the backtrace code"
2358	depends on DEBUG_KERNEL
2359	help
2360	This option provides a kernel module that can be used to test
2361	the kernel stack backtrace code. This option is not useful
2362	for distributions or general kernels, but only for kernel
2363	developers working on architecture code.
2364
2365	Note that if you want to also test saved backtraces, you will
2366	have to enable STACKTRACE as well.
2367
2368	Say N if you are unsure.
2369
2370	config TEST_REF_TRACKER
2371	tristate "Self test for reference tracker"
2372	depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2373	select REF_TRACKER
2374	help
2375	This option provides a kernel module performing tests
2376	using reference tracker infrastructure.
2377
2378	Say N if you are unsure.
2379
2380	config RBTREE_TEST
2381	tristate "Red-Black tree test"
2382	depends on DEBUG_KERNEL
2383	help
2384	A benchmark measuring the performance of the rbtree library.
2385	Also includes rbtree invariant checks.
2386
2387	config REED_SOLOMON_TEST
2388	tristate "Reed-Solomon library test"
2389	depends on DEBUG_KERNEL \|\| m
2390	select REED_SOLOMON
2391	select REED_SOLOMON_ENC16
2392	select REED_SOLOMON_DEC16
2393	help
2394	This option enables the self-test function of rslib at boot,
2395	or at module load time.
2396
2397	If unsure, say N.
2398
2399	config INTERVAL_TREE_TEST
2400	tristate "Interval tree test"
2401	depends on DEBUG_KERNEL
2402	select INTERVAL_TREE
2403	help
2404	A benchmark measuring the performance of the interval tree library
2405
2406	config PERCPU_TEST
2407	tristate "Per cpu operations test"
2408	depends on m && DEBUG_KERNEL
2409	help
2410	Enable this option to build test module which validates per-cpu
2411	operations.
2412
2413	If unsure, say N.
2414
2415	config ATOMIC64_SELFTEST
2416	tristate "Perform an atomic64_t self-test"
2417	help
2418	Enable this option to test the atomic64_t functions at boot or
2419	at module load time.
2420
2421	If unsure, say N.
2422
2423	config ASYNC_RAID6_TEST
2424	tristate "Self test for hardware accelerated raid6 recovery"
2425	depends on ASYNC_RAID6_RECOV
2426	select ASYNC_MEMCPY
2427	help
2428	This is a one-shot self test that permutes through the
2429	recovery of all the possible two disk failure scenarios for a
2430	N-disk array. Recovery is performed with the asynchronous
2431	raid6 recovery routines, and will optionally use an offload
2432	engine if one is available.
2433
2434	If unsure, say N.
2435
2436	config TEST_HEXDUMP
2437	tristate "Test functions located in the hexdump module at runtime"
2438
2439	config PRINTF_KUNIT_TEST
2440	tristate "KUnit test printf() family of functions at runtime" if !KUNIT_ALL_TESTS
2441	depends on KUNIT
2442	default KUNIT_ALL_TESTS
2443	help
2444	Enable this option to test the printf functions at runtime.
2445
2446	If unsure, say N.
2447
2448	config SCANF_KUNIT_TEST
2449	tristate "KUnit test scanf() family of functions at runtime" if !KUNIT_ALL_TESTS
2450	depends on KUNIT
2451	default KUNIT_ALL_TESTS
2452	help
2453	Enable this option to test the scanf functions at runtime.
2454
2455	If unsure, say N.
2456
2457	config SEQ_BUF_KUNIT_TEST
2458	tristate "KUnit test for seq_buf" if !KUNIT_ALL_TESTS
2459	depends on KUNIT
2460	default KUNIT_ALL_TESTS
2461	help
2462	This builds unit tests for the seq_buf library.
2463
2464	If unsure, say N.
2465
2466	config STRING_KUNIT_TEST
2467	tristate "KUnit test string functions at runtime" if !KUNIT_ALL_TESTS
2468	depends on KUNIT
2469	default KUNIT_ALL_TESTS
2470
2471	config STRING_HELPERS_KUNIT_TEST
2472	tristate "KUnit test string helpers at runtime" if !KUNIT_ALL_TESTS
2473	depends on KUNIT
2474	default KUNIT_ALL_TESTS
2475
2476	config FFS_KUNIT_TEST
2477	tristate "KUnit test ffs-family functions at runtime" if !KUNIT_ALL_TESTS
2478	depends on KUNIT
2479	default KUNIT_ALL_TESTS
2480	help
2481	This builds KUnit tests for ffs-family bit manipulation functions
2482	including ffs(), __ffs(), fls(), __fls(), fls64(), and __ffs64().
2483
2484	These tests validate mathematical correctness, edge case handling,
2485	and cross-architecture consistency of bit scanning functions.
2486
2487	For more information on KUnit and unit tests in general,
2488	please refer to Documentation/dev-tools/kunit/.
2489
2490	config TEST_KSTRTOX
2491	tristate "Test kstrto*() family of functions at runtime"
2492
2493	config TEST_BITMAP
2494	tristate "Test bitmap_*() family of functions at runtime"
2495	help
2496	Enable this option to test the bitmap functions at boot.
2497
2498	If unsure, say N.
2499
2500	config TEST_UUID
2501	tristate "Test functions located in the uuid module at runtime"
2502
2503	config TEST_XARRAY
2504	tristate "Test the XArray code at runtime"
2505
2506	config TEST_MAPLE_TREE
2507	tristate "Test the Maple Tree code at runtime or module load"
2508	help
2509	Enable this option to test the maple tree code functions at boot, or
2510	when the module is loaded. Enable "Debug Maple Trees" will enable
2511	more verbose output on failures.
2512
2513	If unsure, say N.
2514
2515	config TEST_RHASHTABLE
2516	tristate "Perform selftest on resizable hash table"
2517	help
2518	Enable this option to test the rhashtable functions at boot.
2519
2520	If unsure, say N.
2521
2522	config TEST_IDA
2523	tristate "Perform selftest on IDA functions"
2524
2525	config TEST_MISC_MINOR
2526	bool "miscdevice KUnit test" if !KUNIT_ALL_TESTS
2527	depends on KUNIT=y
2528	default KUNIT_ALL_TESTS
2529	help
2530	Kunit test for miscdevice API, specially its behavior in respect to
2531	static and dynamic minor numbers.
2532
2533	KUnit tests run during boot and output the results to the debug log
2534	in TAP format (https://testanything.org/). Only useful for kernel devs
2535	running the KUnit test harness, and not intended for inclusion into a
2536	production build.
2537
2538	For more information on KUnit and unit tests in general please refer
2539	to the KUnit documentation in Documentation/dev-tools/kunit/.
2540
2541	If unsure, say N.
2542
2543	config TEST_PARMAN
2544	tristate "Perform selftest on priority array manager"
2545	depends on PARMAN
2546	help
2547	Enable this option to test priority array manager on boot
2548	(or module load).
2549
2550	If unsure, say N.
2551
2552	config TEST_IRQ_TIMINGS
2553	bool "IRQ timings selftest"
2554	depends on IRQ_TIMINGS
2555	help
2556	Enable this option to test the irq timings code on boot.
2557
2558	If unsure, say N.
2559
2560	config TEST_LKM
2561	tristate "Test module loading with 'hello world' module"
2562	depends on m
2563	help
2564	This builds the "test_module" module that emits "Hello, world"
2565	on printk when loaded. It is designed to be used for basic
2566	evaluation of the module loading subsystem (for example when
2567	validating module verification). It lacks any extra dependencies,
2568	and will not normally be loaded by the system unless explicitly
2569	requested by name.
2570
2571	If unsure, say N.
2572
2573	config TEST_BITOPS
2574	tristate "Test module for compilation of bitops operations"
2575	help
2576	This builds the "test_bitops" module that is much like the
2577	TEST_LKM module except that it does a basic exercise of the
2578	set/clear_bit macros and get_count_order/long to make sure there are
2579	no compiler warnings from C=1 sparse checker or -Wextra
2580	compilations. It has no dependencies and doesn't run or load unless
2581	explicitly requested by name. for example: modprobe test_bitops.
2582
2583	If unsure, say N.
2584
2585	config TEST_VMALLOC
2586	tristate "Test module for stress/performance analysis of vmalloc allocator"
2587	default n
2588	depends on MMU
2589	help
2590	This builds the "test_vmalloc" module that should be used for
2591	stress and performance analysis. So, any new change for vmalloc
2592	subsystem can be evaluated from performance and stability point
2593	of view.
2594
2595	If unsure, say N.
2596
2597	config TEST_BPF
2598	tristate "Test BPF filter functionality"
2599	depends on m && NET
2600	help
2601	This builds the "test_bpf" module that runs various test vectors
2602	against the BPF interpreter or BPF JIT compiler depending on the
2603	current setting. This is in particular useful for BPF JIT compiler
2604	development, but also to run regression tests against changes in
2605	the interpreter code. It also enables test stubs for eBPF maps and
2606	verifier used by user space verifier testsuite.
2607
2608	If unsure, say N.
2609
2610	config FIND_BIT_BENCHMARK
2611	tristate "Test find_bit functions"
2612	help
2613	This builds the "test_find_bit" module that measure find_*_bit()
2614	functions performance.
2615
2616	If unsure, say N.
2617
2618	config FIND_BIT_BENCHMARK_RUST
2619	tristate "Test find_bit functions in Rust"
2620	depends on RUST
2621	help
2622	This builds the "find_bit_benchmark_rust" module. It is a micro
2623	benchmark that measures the performance of Rust functions that
2624	correspond to the find_*_bit() operations in C. It follows the
2625	FIND_BIT_BENCHMARK closely but will in general not yield same
2626	numbers due to extra bounds checks and overhead of foreign
2627	function calls.
2628
2629	If unsure, say N.
2630
2631	config TEST_FIRMWARE
2632	tristate "Test firmware loading via userspace interface"
2633	depends on FW_LOADER
2634	help
2635	This builds the "test_firmware" module that creates a userspace
2636	interface for testing firmware loading. This can be used to
2637	control the triggering of firmware loading without needing an
2638	actual firmware-using device. The contents can be rechecked by
2639	userspace.
2640
2641	If unsure, say N.
2642
2643	config TEST_SYSCTL
2644	tristate "sysctl test driver"
2645	depends on PROC_SYSCTL
2646	help
2647	This builds the "test_sysctl" module. This driver enables to test the
2648	proc sysctl interfaces available to drivers safely without affecting
2649	production knobs which might alter system functionality.
2650
2651	If unsure, say N.
2652
2653	config BITFIELD_KUNIT
2654	tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2655	depends on KUNIT
2656	default KUNIT_ALL_TESTS
2657	help
2658	Enable this option to test the bitfield functions at boot.
2659
2660	KUnit tests run during boot and output the results to the debug log
2661	in TAP format (http://testanything.org/). Only useful for kernel devs
2662	running the KUnit test harness, and not intended for inclusion into a
2663	production build.
2664
2665	For more information on KUnit and unit tests in general please refer
2666	to the KUnit documentation in Documentation/dev-tools/kunit/.
2667
2668	If unsure, say N.
2669
2670	config CHECKSUM_KUNIT
2671	tristate "KUnit test checksum functions at runtime" if !KUNIT_ALL_TESTS
2672	depends on KUNIT
2673	default KUNIT_ALL_TESTS
2674	help
2675	Enable this option to test the checksum functions at boot.
2676
2677	KUnit tests run during boot and output the results to the debug log
2678	in TAP format (http://testanything.org/). Only useful for kernel devs
2679	running the KUnit test harness, and not intended for inclusion into a
2680	production build.
2681
2682	For more information on KUnit and unit tests in general please refer
2683	to the KUnit documentation in Documentation/dev-tools/kunit/.
2684
2685	If unsure, say N.
2686
2687	config UTIL_MACROS_KUNIT
2688	tristate "KUnit test util_macros.h functions at runtime" if !KUNIT_ALL_TESTS
2689	depends on KUNIT
2690	default KUNIT_ALL_TESTS
2691	help
2692	Enable this option to test the util_macros.h function at boot.
2693
2694	KUnit tests run during boot and output the results to the debug log
2695	in TAP format (http://testanything.org/). Only useful for kernel devs
2696	running the KUnit test harness, and not intended for inclusion into a
2697	production build.
2698
2699	For more information on KUnit and unit tests in general please refer
2700	to the KUnit documentation in Documentation/dev-tools/kunit/.
2701
2702	If unsure, say N.
2703
2704	config HASH_KUNIT_TEST
2705	tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2706	depends on KUNIT
2707	default KUNIT_ALL_TESTS
2708	help
2709	Enable this option to test the kernel's string (<linux/stringhash.h>), and
2710	integer (<linux/hash.h>) hash functions on boot.
2711
2712	KUnit tests run during boot and output the results to the debug log
2713	in TAP format (https://testanything.org/). Only useful for kernel devs
2714	running the KUnit test harness, and not intended for inclusion into a
2715	production build.
2716
2717	For more information on KUnit and unit tests in general please refer
2718	to the KUnit documentation in Documentation/dev-tools/kunit/.
2719
2720	This is intended to help people writing architecture-specific
2721	optimized versions. If unsure, say N.
2722
2723	config RESOURCE_KUNIT_TEST
2724	tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2725	depends on KUNIT
2726	default KUNIT_ALL_TESTS
2727	select GET_FREE_REGION
2728	help
2729	This builds the resource API unit test.
2730	Tests the logic of API provided by resource.c and ioport.h.
2731	For more information on KUnit and unit tests in general please refer
2732	to the KUnit documentation in Documentation/dev-tools/kunit/.
2733
2734	If unsure, say N.
2735
2736	config SYSCTL_KUNIT_TEST
2737	tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2738	depends on KUNIT
2739	default KUNIT_ALL_TESTS
2740	help
2741	This builds the proc sysctl unit test, which runs on boot.
2742	Tests the API contract and implementation correctness of sysctl.
2743	For more information on KUnit and unit tests in general please refer
2744	to the KUnit documentation in Documentation/dev-tools/kunit/.
2745
2746	If unsure, say N.
2747
2748	config KFIFO_KUNIT_TEST
2749	tristate "KUnit Test for the generic kernel FIFO implementation" if !KUNIT_ALL_TESTS
2750	depends on KUNIT
2751	default KUNIT_ALL_TESTS
2752	help
2753	This builds the generic FIFO implementation KUnit test suite.
2754	It tests that the API and basic functionality of the kfifo type
2755	and associated macros.
2756
2757	For more information on KUnit and unit tests in general please refer
2758	to the KUnit documentation in Documentation/dev-tools/kunit/.
2759
2760	If unsure, say N.
2761
2762	config LIST_KUNIT_TEST
2763	tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2764	depends on KUNIT
2765	default KUNIT_ALL_TESTS
2766	help
2767	This builds the linked list KUnit test suite.
2768	It tests that the API and basic functionality of the list_head type
2769	and associated macros.
2770
2771	KUnit tests run during boot and output the results to the debug log
2772	in TAP format (https://testanything.org/). Only useful for kernel devs
2773	running the KUnit test harness, and not intended for inclusion into a
2774	production build.
2775
2776	For more information on KUnit and unit tests in general please refer
2777	to the KUnit documentation in Documentation/dev-tools/kunit/.
2778
2779	If unsure, say N.
2780
2781	config HASHTABLE_KUNIT_TEST
2782	tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS
2783	depends on KUNIT
2784	default KUNIT_ALL_TESTS
2785	help
2786	This builds the hashtable KUnit test suite.
2787	It tests the basic functionality of the API defined in
2788	include/linux/hashtable.h. For more information on KUnit and
2789	unit tests in general please refer to the KUnit documentation
2790	in Documentation/dev-tools/kunit/.
2791
2792	If unsure, say N.
2793
2794	config LINEAR_RANGES_TEST
2795	tristate "KUnit test for linear_ranges"
2796	depends on KUNIT
2797	select LINEAR_RANGES
2798	help
2799	This builds the linear_ranges unit test, which runs on boot.
2800	Tests the linear_ranges logic correctness.
2801	For more information on KUnit and unit tests in general please refer
2802	to the KUnit documentation in Documentation/dev-tools/kunit/.
2803
2804	If unsure, say N.
2805
2806	config CMDLINE_KUNIT_TEST
2807	tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2808	depends on KUNIT
2809	default KUNIT_ALL_TESTS
2810	help
2811	This builds the cmdline API unit test.
2812	Tests the logic of API provided by cmdline.c.
2813	For more information on KUnit and unit tests in general please refer
2814	to the KUnit documentation in Documentation/dev-tools/kunit/.
2815
2816	If unsure, say N.
2817
2818	config BITS_TEST
2819	tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2820	depends on KUNIT
2821	default KUNIT_ALL_TESTS
2822	help
2823	This builds the bits unit test.
2824	Tests the logic of macros defined in bits.h.
2825	For more information on KUnit and unit tests in general please refer
2826	to the KUnit documentation in Documentation/dev-tools/kunit/.
2827
2828	If unsure, say N.
2829
2830	config SLUB_KUNIT_TEST
2831	tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2832	depends on SLUB_DEBUG && KUNIT
2833	default KUNIT_ALL_TESTS
2834	help
2835	This builds SLUB allocator unit test.
2836	Tests SLUB cache debugging functionality.
2837	For more information on KUnit and unit tests in general please refer
2838	to the KUnit documentation in Documentation/dev-tools/kunit/.
2839
2840	If unsure, say N.
2841
2842	config RATIONAL_KUNIT_TEST
2843	tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2844	depends on KUNIT && RATIONAL
2845	default KUNIT_ALL_TESTS
2846	help
2847	This builds the rational math unit test.
2848	For more information on KUnit and unit tests in general please refer
2849	to the KUnit documentation in Documentation/dev-tools/kunit/.
2850
2851	If unsure, say N.
2852
2853	config MEMCPY_KUNIT_TEST
2854	tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2855	depends on KUNIT
2856	default KUNIT_ALL_TESTS
2857	help
2858	Builds unit tests for memcpy(), memmove(), and memset() functions.
2859	For more information on KUnit and unit tests in general please refer
2860	to the KUnit documentation in Documentation/dev-tools/kunit/.
2861
2862	If unsure, say N.
2863
2864	config IS_SIGNED_TYPE_KUNIT_TEST
2865	tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2866	depends on KUNIT
2867	default KUNIT_ALL_TESTS
2868	help
2869	Builds unit tests for the is_signed_type() macro.
2870
2871	For more information on KUnit and unit tests in general please refer
2872	to the KUnit documentation in Documentation/dev-tools/kunit/.
2873
2874	If unsure, say N.
2875
2876	config OVERFLOW_KUNIT_TEST
2877	tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2878	depends on KUNIT
2879	default KUNIT_ALL_TESTS
2880	help
2881	Builds unit tests for the check__overflow(), size_(), allocation, and
2882	related functions.
2883
2884	For more information on KUnit and unit tests in general please refer
2885	to the KUnit documentation in Documentation/dev-tools/kunit/.
2886
2887	If unsure, say N.
2888
2889	config RANDSTRUCT_KUNIT_TEST
2890	tristate "Test randstruct structure layout randomization at runtime" if !KUNIT_ALL_TESTS
2891	depends on KUNIT
2892	default KUNIT_ALL_TESTS
2893	help
2894	Builds unit tests for the checking CONFIG_RANDSTRUCT=y, which
2895	randomizes structure layouts.
2896
2897	config STACKINIT_KUNIT_TEST
2898	tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2899	depends on KUNIT
2900	default KUNIT_ALL_TESTS
2901	help
2902	Test if the kernel is zero-initializing stack variables and
2903	padding. Coverage is controlled by compiler flags,
2904	CONFIG_INIT_STACK_ALL_PATTERN or CONFIG_INIT_STACK_ALL_ZERO.
2905
2906	config FORTIFY_KUNIT_TEST
2907	tristate "Test fortified str() and mem() function internals at runtime" if !KUNIT_ALL_TESTS
2908	depends on KUNIT
2909	default KUNIT_ALL_TESTS
2910	help
2911	Builds unit tests for checking internals of FORTIFY_SOURCE as used
2912	by the str() and mem() family of functions. For testing runtime
2913	traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2914
2915	config LONGEST_SYM_KUNIT_TEST
2916	tristate "Test the longest symbol possible" if !KUNIT_ALL_TESTS
2917	depends on KUNIT && KPROBES
2918	depends on !PREFIX_SYMBOLS && !CFI && !GCOV_KERNEL
2919	default KUNIT_ALL_TESTS
2920	help
2921	Tests the longest symbol possible
2922
2923	If unsure, say N.
2924
2925	config HW_BREAKPOINT_KUNIT_TEST
2926	bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2927	depends on HAVE_HW_BREAKPOINT
2928	depends on KUNIT=y
2929	default KUNIT_ALL_TESTS
2930	help
2931	Tests for hw_breakpoint constraints accounting.
2932
2933	If unsure, say N.
2934
2935	config SIPHASH_KUNIT_TEST
2936	tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2937	depends on KUNIT
2938	default KUNIT_ALL_TESTS
2939	help
2940	Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2941	functions on boot (or module load).
2942
2943	This is intended to help people writing architecture-specific
2944	optimized versions. If unsure, say N.
2945
2946	config USERCOPY_KUNIT_TEST
2947	tristate "KUnit Test for user/kernel boundary protections"
2948	depends on KUNIT
2949	default KUNIT_ALL_TESTS
2950	help
2951	This builds the "usercopy_kunit" module that runs sanity checks
2952	on the copy_to/from_user infrastructure, making sure basic
2953	user/kernel boundary testing is working.
2954
2955	config BLACKHOLE_DEV_KUNIT_TEST
2956	tristate "Test blackhole netdev functionality" if !KUNIT_ALL_TESTS
2957	depends on NET
2958	depends on KUNIT
2959	default KUNIT_ALL_TESTS
2960	help
2961	This builds the "blackhole_dev_kunit" module that validates the
2962	data path through this blackhole netdev.
2963
2964	If unsure, say N.
2965
2966	config TEST_UDELAY
2967	tristate "udelay test driver"
2968	help
2969	This builds the "udelay_test" module that helps to make sure
2970	that udelay() is working properly.
2971
2972	If unsure, say N.
2973
2974	config TEST_STATIC_KEYS
2975	tristate "Test static keys"
2976	depends on m
2977	help
2978	Test the static key interfaces.
2979
2980	If unsure, say N.
2981
2982	config TEST_DYNAMIC_DEBUG
2983	tristate "Test DYNAMIC_DEBUG"
2984	depends on DYNAMIC_DEBUG
2985	help
2986	This module registers a tracer callback to count enabled
2987	pr_debugs in a 'do_debugging' function, then alters their
2988	enablements, calls the function, and compares counts.
2989
2990	If unsure, say N.
2991
2992	config TEST_KMOD
2993	tristate "kmod stress tester"
2994	depends on m
2995	select TEST_LKM
2996	help
2997	Test the kernel's module loading mechanism: kmod. kmod implements
2998	support to load modules using the Linux kernel's usermode helper.
2999	This test provides a series of tests against kmod.
3000
3001	Although technically you can either build test_kmod as a module or
3002	into the kernel we disallow building it into the kernel since
3003	it stress tests request_module() and this will very likely cause
3004	some issues by taking over precious threads available from other
3005	module load requests, ultimately this could be fatal.
3006
3007	To run tests run:
3008
3009	tools/testing/selftests/kmod/kmod.sh --help
3010
3011	If unsure, say N.
3012
3013	config TEST_RUNTIME
3014	bool
3015
3016	config TEST_RUNTIME_MODULE
3017	bool
3018
3019	config TEST_KALLSYMS
3020	tristate "module kallsyms find_symbol() test"
3021	depends on m
3022	select TEST_RUNTIME
3023	select TEST_RUNTIME_MODULE
3024	select TEST_KALLSYMS_A
3025	select TEST_KALLSYMS_B
3026	select TEST_KALLSYMS_C
3027	select TEST_KALLSYMS_D
3028	help
3029	This allows us to stress test find_symbol() through the kallsyms
3030	used to place symbols on the kernel ELF kallsyms and modules kallsyms
3031	where we place kernel symbols such as exported symbols.
3032
3033	We have four test modules:
3034
3035	A: has KALLSYSMS_NUMSYMS exported symbols
3036	B: uses one of A's symbols
3037	C: adds KALLSYMS_SCALE_FACTOR * KALLSYSMS_NUMSYMS exported
3038	D: adds 2 * the symbols than C
3039
3040	We stress test find_symbol() through two means:
3041
3042	1) Upon load of B it will trigger simplify_symbols() to look for the
3043	one symbol it uses from the module A with tons of symbols. This is an
3044	indirect way for us to have B call resolve_symbol_wait() upon module
3045	load. This will eventually call find_symbol() which will eventually
3046	try to find the symbols used with find_exported_symbol_in_section().
3047	find_exported_symbol_in_section() uses bsearch() so a binary search
3048	for each symbol. Binary search will at worst be O(log(n)) so the
3049	larger TEST_MODULE_KALLSYSMS the worse the search.
3050
3051	2) The selftests should load C first, before B. Upon B's load towards
3052	the end right before we call module B's init routine we get
3053	complete_formation() called on the module. That will first check
3054	for duplicate symbols with the call to verify_exported_symbols().
3055	That is when we'll force iteration on module C's insane symbol list.
3056	Since it has 10 * KALLSYMS_NUMSYMS it means we can first test
3057	just loading B without C. The amount of time it takes to load C Vs
3058	B can give us an idea of the impact growth of the symbol space and
3059	give us projection. Module A only uses one symbol from B so to allow
3060	this scaling in module C to be proportional, if it used more symbols
3061	then the first test would be doing more and increasing just the
3062	search space would be slightly different. The last module, module D
3063	will just increase the search space by twice the number of symbols in
3064	C so to allow for full projects.
3065
3066	tools/testing/selftests/module/find_symbol.sh
3067
3068	The current defaults will incur a build delay of about 7 minutes
3069	on an x86_64 with only 8 cores. Enable this only if you want to
3070	stress test find_symbol() with thousands of symbols. At the same
3071	time this is also useful to test building modules with thousands of
3072	symbols, and if BTF is enabled this also stress tests adding BTF
3073	information for each module. Currently enabling many more symbols
3074	will segfault the build system.
3075
3076	If unsure, say N.
3077
3078	if TEST_KALLSYMS
3079
3080	config TEST_KALLSYMS_A
3081	tristate
3082	depends on m
3083
3084	config TEST_KALLSYMS_B
3085	tristate
3086	depends on m
3087
3088	config TEST_KALLSYMS_C
3089	tristate
3090	depends on m
3091
3092	config TEST_KALLSYMS_D
3093	tristate
3094	depends on m
3095
3096	choice
3097	prompt "Kallsym test range"
3098	default TEST_KALLSYMS_LARGE
3099	help
3100	Selecting something other than "Fast" will enable tests which slow
3101	down the build and may crash your build.
3102
3103	config TEST_KALLSYMS_FAST
3104	bool "Fast builds"
3105	help
3106	You won't really be testing kallsysms, so this just helps fast builds
3107	when allmodconfig is used..
3108
3109	config TEST_KALLSYMS_LARGE
3110	bool "Enable testing kallsyms with large exports"
3111	help
3112	This will enable larger number of symbols. This will slow down
3113	your build considerably.
3114
3115	config TEST_KALLSYMS_MAX
3116	bool "Known kallsysms limits"
3117	help
3118	This will enable exports to the point we know we'll start crashing
3119	builds.
3120
3121	endchoice
3122
3123	config TEST_KALLSYMS_NUMSYMS
3124	int "test kallsyms number of symbols"
3125	range 2 10000
3126	default 2 if TEST_KALLSYMS_FAST
3127	default 100 if TEST_KALLSYMS_LARGE
3128	default 10000 if TEST_KALLSYMS_MAX
3129	help
3130	The number of symbols to create on TEST_KALLSYMS_A, only one of which
3131	module TEST_KALLSYMS_B will use. This also will be used
3132	for how many symbols TEST_KALLSYMS_C will have, scaled up by
3133	TEST_KALLSYMS_SCALE_FACTOR. Note that setting this to 10,000 will
3134	trigger a segfault today, don't use anything close to it unless
3135	you are aware that this should not be used for automated build tests.
3136
3137	config TEST_KALLSYMS_SCALE_FACTOR
3138	int "test kallsyms scale factor"
3139	default 8
3140	help
3141	How many more unusued symbols will TEST_KALLSYSMS_C have than
3142	TEST_KALLSYMS_A. If 8, then module C will have 8 * syms
3143	than module A. Then TEST_KALLSYMS_D will have double the amount
3144	of symbols than C so to allow projections.
3145
3146	endif # TEST_KALLSYMS
3147
3148	config TEST_DEBUG_VIRTUAL
3149	tristate "Test CONFIG_DEBUG_VIRTUAL feature"
3150	depends on DEBUG_VIRTUAL
3151	help
3152	Test the kernel's ability to detect incorrect calls to
3153	virt_to_phys() done against the non-linear part of the
3154	kernel's virtual address map.
3155
3156	If unsure, say N.
3157
3158	config TEST_MEMCAT_P
3159	tristate "Test memcat_p() helper function"
3160	help
3161	Test the memcat_p() helper for correctly merging two
3162	pointer arrays together.
3163
3164	If unsure, say N.
3165
3166	config TEST_OBJAGG
3167	tristate "Perform selftest on object aggreration manager"
3168	default n
3169	depends on OBJAGG
3170	help
3171	Enable this option to test object aggregation manager on boot
3172	(or module load).
3173
3174	config TEST_MEMINIT
3175	tristate "Test heap/page initialization"
3176	help
3177	Test if the kernel is zero-initializing heap and page allocations.
3178	This can be useful to test init_on_alloc and init_on_free features.
3179
3180	If unsure, say N.
3181
3182	config TEST_HMM
3183	tristate "Test HMM (Heterogeneous Memory Management)"
3184	depends on TRANSPARENT_HUGEPAGE
3185	depends on DEVICE_PRIVATE
3186	select HMM_MIRROR
3187	select MMU_NOTIFIER
3188	help
3189	This is a pseudo device driver solely for testing HMM.
3190	Say M here if you want to build the HMM test module.
3191	Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
3192
3193	If unsure, say N.
3194
3195	config TEST_FREE_PAGES
3196	tristate "Test freeing pages"
3197	help
3198	Test that a memory leak does not occur due to a race between
3199	freeing a block of pages and a speculative page reference.
3200	Loading this module is safe if your kernel has the bug fixed.
3201	If the bug is not fixed, it will leak gigabytes of memory and
3202	probably OOM your system.
3203
3204	config TEST_FPU
3205	tristate "Test floating point operations in kernel space"
3206	depends on ARCH_HAS_KERNEL_FPU_SUPPORT && !KCOV_INSTRUMENT_ALL
3207	help
3208	Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
3209	which will trigger a sequence of floating point operations. This is used
3210	for self-testing floating point control register setting in
3211	kernel_fpu_begin().
3212
3213	If unsure, say N.
3214
3215	config TEST_CLOCKSOURCE_WATCHDOG
3216	tristate "Test clocksource watchdog in kernel space"
3217	depends on CLOCKSOURCE_WATCHDOG
3218	help
3219	Enable this option to create a kernel module that will trigger
3220	a test of the clocksource watchdog. This module may be loaded
3221	via modprobe or insmod in which case it will run upon being
3222	loaded, or it may be built in, in which case it will run
3223	shortly after boot.
3224
3225	If unsure, say N.
3226
3227	config TEST_OBJPOOL
3228	tristate "Test module for correctness and stress of objpool"
3229	default n
3230	depends on m && DEBUG_KERNEL
3231	help
3232	This builds the "test_objpool" module that should be used for
3233	correctness verification and concurrent testings of objects
3234	allocation and reclamation.
3235
3236	If unsure, say N.
3237
3238	config TEST_KEXEC_HANDOVER
3239	bool "Test for Kexec HandOver"
3240	default n
3241	depends on KEXEC_HANDOVER
3242	help
3243	This option enables test for Kexec HandOver (KHO).
3244	The test consists of two parts: saving kernel data before kexec and
3245	restoring the data after kexec and verifying that it was properly
3246	handed over. This test module creates and saves data on the boot of
3247	the first kernel and restores and verifies the data on the boot of
3248	kexec'ed kernel.
3249
3250	For detailed documentation about KHO, see Documentation/core-api/kho.
3251
3252	To run the test run:
3253
3254	tools/testing/selftests/kho/vmtest.sh -h
3255
3256	If unsure, say N.
3257
3258	config RATELIMIT_KUNIT_TEST
3259	tristate "KUnit Test for correctness and stress of ratelimit" if !KUNIT_ALL_TESTS
3260	depends on KUNIT
3261	default KUNIT_ALL_TESTS
3262	help
3263	This builds the "test_ratelimit" module that should be used
3264	for correctness verification and concurrent testings of rate
3265	limiting.
3266
3267	If unsure, say N.
3268
3269	config INT_POW_KUNIT_TEST
3270	tristate "Integer exponentiation (int_pow) test" if !KUNIT_ALL_TESTS
3271	depends on KUNIT
3272	default KUNIT_ALL_TESTS
3273	help
3274	This option enables the KUnit test suite for the int_pow function,
3275	which performs integer exponentiation. The test suite is designed to
3276	verify that the implementation of int_pow correctly computes the power
3277	of a given base raised to a given exponent.
3278
3279	Enabling this option will include tests that check various scenarios
3280	and edge cases to ensure the accuracy and reliability of the exponentiation
3281	function.
3282
3283	If unsure, say N
3284
3285	config INT_SQRT_KUNIT_TEST
3286	tristate "Integer square root test" if !KUNIT_ALL_TESTS
3287	depends on KUNIT
3288	default KUNIT_ALL_TESTS
3289	help
3290	This option enables the KUnit test suite for the int_sqrt() function,
3291	which performs square root calculation. The test suite checks
3292	various scenarios, including edge cases, to ensure correctness.
3293
3294	Enabling this option will include tests that check various scenarios
3295	and edge cases to ensure the accuracy and reliability of the square root
3296	function.
3297
3298	If unsure, say N
3299
3300	config INT_LOG_KUNIT_TEST
3301	tristate "Integer log (int_log) test" if !KUNIT_ALL_TESTS
3302	depends on KUNIT
3303	default KUNIT_ALL_TESTS
3304	help
3305	This option enables the KUnit test suite for the int_log library, which
3306	provides two functions to compute the integer logarithm in base 2 and
3307	base 10, called respectively as intlog2 and intlog10.
3308
3309	If unsure, say N
3310
3311	config GCD_KUNIT_TEST
3312	tristate "Greatest common divisor test" if !KUNIT_ALL_TESTS
3313	depends on KUNIT
3314	default KUNIT_ALL_TESTS
3315	help
3316	This option enables the KUnit test suite for the gcd() function,
3317	which computes the greatest common divisor of two numbers.
3318
3319	This test suite verifies the correctness of gcd() across various
3320	scenarios, including edge cases.
3321
3322	If unsure, say N
3323
3324	config PRIME_NUMBERS_KUNIT_TEST
3325	tristate "Prime number generator test" if !KUNIT_ALL_TESTS
3326	depends on KUNIT
3327	depends on PRIME_NUMBERS
3328	default KUNIT_ALL_TESTS
3329	help
3330	This option enables the KUnit test suite for the {is,next}_prime_number
3331	functions.
3332
3333	Enabling this option will include tests that compare the prime number
3334	generator functions against a brute force implementation.
3335
3336	If unsure, say N
3337
3338	endif # RUNTIME_TESTING_MENU
3339
3340	config ARCH_USE_MEMTEST
3341	bool
3342	help
3343	An architecture should select this when it uses early_memtest()
3344	during boot process.
3345
3346	config MEMTEST
3347	bool "Memtest"
3348	depends on ARCH_USE_MEMTEST
3349	help
3350	This option adds a kernel parameter 'memtest', which allows memtest
3351	to be set and executed.
3352	memtest=0, mean disabled; -- default
3353	memtest=1, mean do 1 test pattern;
3354	...
3355	memtest=17, mean do 17 test patterns.
3356	If you are unsure how to answer this question, answer N.
3357
3358
3359
3360	config HYPERV_TESTING
3361	bool "Microsoft Hyper-V driver testing"
3362	default n
3363	depends on HYPERV && DEBUG_FS
3364	help
3365	Select this option to enable Hyper-V vmbus testing.
3366
3367	endmenu # "Kernel Testing and Coverage"
3368
3369	menu "Rust hacking"
3370
3371	config RUST_DEBUG_ASSERTIONS
3372	bool "Debug assertions"
3373	depends on RUST
3374	help
3375	Enables rustc's `-Cdebug-assertions` codegen option.
3376
3377	This flag lets you turn `cfg(debug_assertions)` conditional
3378	compilation on or off. This can be used to enable extra debugging
3379	code in development but not in production. For example, it controls
3380	the behavior of the standard library's `debug_assert!` macro.
3381
3382	Note that this will apply to all Rust code, including `core`.
3383
3384	If unsure, say N.
3385
3386	config RUST_OVERFLOW_CHECKS
3387	bool "Overflow checks"
3388	default y
3389	depends on RUST
3390	help
3391	Enables rustc's `-Coverflow-checks` codegen option.
3392
3393	This flag allows you to control the behavior of runtime integer
3394	overflow. When overflow-checks are enabled, a Rust panic will occur
3395	on overflow.
3396
3397	Note that this will apply to all Rust code, including `core`.
3398
3399	If unsure, say Y.
3400
3401	config RUST_BUILD_ASSERT_ALLOW
3402	bool "Allow unoptimized build-time assertions"
3403	depends on RUST
3404	help
3405	Controls how `build_error!` and `build_assert!` are handled during the build.
3406
3407	If calls to them exist in the binary, it may indicate a violated invariant
3408	or that the optimizer failed to verify the invariant during compilation.
3409
3410	This should not happen, thus by default the build is aborted. However,
3411	as an escape hatch, you can choose Y here to ignore them during build
3412	and let the check be carried at runtime (with `panic!` being called if
3413	the check fails).
3414
3415	If unsure, say N.
3416
3417	config RUST_KERNEL_DOCTESTS
3418	bool "Doctests for the `kernel` crate" if !KUNIT_ALL_TESTS
3419	depends on RUST && KUNIT=y
3420	default KUNIT_ALL_TESTS
3421	help
3422	This builds the documentation tests of the `kernel` crate
3423	as KUnit tests.
3424
3425	For more information on KUnit and unit tests in general,
3426	please refer to the KUnit documentation in Documentation/dev-tools/kunit/.
3427
3428	If unsure, say N.
3429
3430	endmenu # "Rust"
3431
3432	endmenu # Kernel hacking