xref: /openbmc/linux/lib/Kconfig.debug (revision 78bb17f7)
1# SPDX-License-Identifier: GPL-2.0-only
2menu "Kernel hacking"
3
4menu "printk and dmesg options"
5
6config PRINTK_TIME
7	bool "Show timing information on printks"
8	depends on PRINTK
9	help
10	  Selecting this option causes time stamps of the printk()
11	  messages to be added to the output of the syslog() system
12	  call and at the console.
13
14	  The timestamp is always recorded internally, and exported
15	  to /dev/kmsg. This flag just specifies if the timestamp should
16	  be included, not that the timestamp is recorded.
17
18	  The behavior is also controlled by the kernel command line
19	  parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
20
21config PRINTK_CALLER
22	bool "Show caller information on printks"
23	depends on PRINTK
24	help
25	  Selecting this option causes printk() to add a caller "thread id" (if
26	  in task context) or a caller "processor id" (if not in task context)
27	  to every message.
28
29	  This option is intended for environments where multiple threads
30	  concurrently call printk() for many times, for it is difficult to
31	  interpret without knowing where these lines (or sometimes individual
32	  line which was divided into multiple lines due to race) came from.
33
34	  Since toggling after boot makes the code racy, currently there is
35	  no option to enable/disable at the kernel command line parameter or
36	  sysfs interface.
37
38config CONSOLE_LOGLEVEL_DEFAULT
39	int "Default console loglevel (1-15)"
40	range 1 15
41	default "7"
42	help
43	  Default loglevel to determine what will be printed on the console.
44
45	  Setting a default here is equivalent to passing in loglevel=<x> in
46	  the kernel bootargs. loglevel=<x> continues to override whatever
47	  value is specified here as well.
48
49	  Note: This does not affect the log level of un-prefixed printk()
50	  usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
51	  option.
52
53config CONSOLE_LOGLEVEL_QUIET
54	int "quiet console loglevel (1-15)"
55	range 1 15
56	default "4"
57	help
58	  loglevel to use when "quiet" is passed on the kernel commandline.
59
60	  When "quiet" is passed on the kernel commandline this loglevel
61	  will be used as the loglevel. IOW passing "quiet" will be the
62	  equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
63
64config MESSAGE_LOGLEVEL_DEFAULT
65	int "Default message log level (1-7)"
66	range 1 7
67	default "4"
68	help
69	  Default log level for printk statements with no specified priority.
70
71	  This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
72	  that are auditing their logs closely may want to set it to a lower
73	  priority.
74
75	  Note: This does not affect what message level gets printed on the console
76	  by default. To change that, use loglevel=<x> in the kernel bootargs,
77	  or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
78
79config BOOT_PRINTK_DELAY
80	bool "Delay each boot printk message by N milliseconds"
81	depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
82	help
83	  This build option allows you to read kernel boot messages
84	  by inserting a short delay after each one.  The delay is
85	  specified in milliseconds on the kernel command line,
86	  using "boot_delay=N".
87
88	  It is likely that you would also need to use "lpj=M" to preset
89	  the "loops per jiffie" value.
90	  See a previous boot log for the "lpj" value to use for your
91	  system, and then set "lpj=M" before setting "boot_delay=N".
92	  NOTE:  Using this option may adversely affect SMP systems.
93	  I.e., processors other than the first one may not boot up.
94	  BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
95	  what it believes to be lockup conditions.
96
97config DYNAMIC_DEBUG
98	bool "Enable dynamic printk() support"
99	default n
100	depends on PRINTK
101	depends on (DEBUG_FS || PROC_FS)
102	help
103
104	  Compiles debug level messages into the kernel, which would not
105	  otherwise be available at runtime. These messages can then be
106	  enabled/disabled based on various levels of scope - per source file,
107	  function, module, format string, and line number. This mechanism
108	  implicitly compiles in all pr_debug() and dev_dbg() calls, which
109	  enlarges the kernel text size by about 2%.
110
111	  If a source file is compiled with DEBUG flag set, any
112	  pr_debug() calls in it are enabled by default, but can be
113	  disabled at runtime as below.  Note that DEBUG flag is
114	  turned on by many CONFIG_*DEBUG* options.
115
116	  Usage:
117
118	  Dynamic debugging is controlled via the 'dynamic_debug/control' file,
119	  which is contained in the 'debugfs' filesystem or procfs.
120	  Thus, the debugfs or procfs filesystem must first be mounted before
121	  making use of this feature.
122	  We refer the control file as: <debugfs>/dynamic_debug/control. This
123	  file contains a list of the debug statements that can be enabled. The
124	  format for each line of the file is:
125
126		filename:lineno [module]function flags format
127
128	  filename : source file of the debug statement
129	  lineno : line number of the debug statement
130	  module : module that contains the debug statement
131	  function : function that contains the debug statement
132	  flags : '=p' means the line is turned 'on' for printing
133	  format : the format used for the debug statement
134
135	  From a live system:
136
137		nullarbor:~ # cat <debugfs>/dynamic_debug/control
138		# filename:lineno [module]function flags format
139		fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
140		fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
141		fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
142
143	  Example usage:
144
145		// enable the message at line 1603 of file svcsock.c
146		nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
147						<debugfs>/dynamic_debug/control
148
149		// enable all the messages in file svcsock.c
150		nullarbor:~ # echo -n 'file svcsock.c +p' >
151						<debugfs>/dynamic_debug/control
152
153		// enable all the messages in the NFS server module
154		nullarbor:~ # echo -n 'module nfsd +p' >
155						<debugfs>/dynamic_debug/control
156
157		// enable all 12 messages in the function svc_process()
158		nullarbor:~ # echo -n 'func svc_process +p' >
159						<debugfs>/dynamic_debug/control
160
161		// disable all 12 messages in the function svc_process()
162		nullarbor:~ # echo -n 'func svc_process -p' >
163						<debugfs>/dynamic_debug/control
164
165	  See Documentation/admin-guide/dynamic-debug-howto.rst for additional
166	  information.
167
168config SYMBOLIC_ERRNAME
169	bool "Support symbolic error names in printf"
170	default y if PRINTK
171	help
172	  If you say Y here, the kernel's printf implementation will
173	  be able to print symbolic error names such as ENOSPC instead
174	  of the number 28. It makes the kernel image slightly larger
175	  (about 3KB), but can make the kernel logs easier to read.
176
177config DEBUG_BUGVERBOSE
178	bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
179	depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
180	default y
181	help
182	  Say Y here to make BUG() panics output the file name and line number
183	  of the BUG call as well as the EIP and oops trace.  This aids
184	  debugging but costs about 70-100K of memory.
185
186endmenu # "printk and dmesg options"
187
188menu "Compile-time checks and compiler options"
189
190config DEBUG_INFO
191	bool "Compile the kernel with debug info"
192	depends on DEBUG_KERNEL && !COMPILE_TEST
193	help
194	  If you say Y here the resulting kernel image will include
195	  debugging info resulting in a larger kernel image.
196	  This adds debug symbols to the kernel and modules (gcc -g), and
197	  is needed if you intend to use kernel crashdump or binary object
198	  tools like crash, kgdb, LKCD, gdb, etc on the kernel.
199	  Say Y here only if you plan to debug the kernel.
200
201	  If unsure, say N.
202
203config DEBUG_INFO_REDUCED
204	bool "Reduce debugging information"
205	depends on DEBUG_INFO
206	help
207	  If you say Y here gcc is instructed to generate less debugging
208	  information for structure types. This means that tools that
209	  need full debugging information (like kgdb or systemtap) won't
210	  be happy. But if you merely need debugging information to
211	  resolve line numbers there is no loss. Advantage is that
212	  build directory object sizes shrink dramatically over a full
213	  DEBUG_INFO build and compile times are reduced too.
214	  Only works with newer gcc versions.
215
216config DEBUG_INFO_SPLIT
217	bool "Produce split debuginfo in .dwo files"
218	depends on DEBUG_INFO
219	depends on $(cc-option,-gsplit-dwarf)
220	help
221	  Generate debug info into separate .dwo files. This significantly
222	  reduces the build directory size for builds with DEBUG_INFO,
223	  because it stores the information only once on disk in .dwo
224	  files instead of multiple times in object files and executables.
225	  In addition the debug information is also compressed.
226
227	  Requires recent gcc (4.7+) and recent gdb/binutils.
228	  Any tool that packages or reads debug information would need
229	  to know about the .dwo files and include them.
230	  Incompatible with older versions of ccache.
231
232config DEBUG_INFO_DWARF4
233	bool "Generate dwarf4 debuginfo"
234	depends on DEBUG_INFO
235	depends on $(cc-option,-gdwarf-4)
236	help
237	  Generate dwarf4 debug info. This requires recent versions
238	  of gcc and gdb. It makes the debug information larger.
239	  But it significantly improves the success of resolving
240	  variables in gdb on optimized code.
241
242config DEBUG_INFO_BTF
243	bool "Generate BTF typeinfo"
244	depends on DEBUG_INFO
245	depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
246	depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
247	help
248	  Generate deduplicated BTF type information from DWARF debug info.
249	  Turning this on expects presence of pahole tool, which will convert
250	  DWARF type info into equivalent deduplicated BTF type info.
251
252config GDB_SCRIPTS
253	bool "Provide GDB scripts for kernel debugging"
254	depends on DEBUG_INFO
255	help
256	  This creates the required links to GDB helper scripts in the
257	  build directory. If you load vmlinux into gdb, the helper
258	  scripts will be automatically imported by gdb as well, and
259	  additional functions are available to analyze a Linux kernel
260	  instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
261	  for further details.
262
263config ENABLE_MUST_CHECK
264	bool "Enable __must_check logic"
265	default y
266	help
267	  Enable the __must_check logic in the kernel build.  Disable this to
268	  suppress the "warning: ignoring return value of 'foo', declared with
269	  attribute warn_unused_result" messages.
270
271config FRAME_WARN
272	int "Warn for stack frames larger than"
273	range 0 8192
274	default 2048 if GCC_PLUGIN_LATENT_ENTROPY
275	default 1280 if (!64BIT && PARISC)
276	default 1024 if (!64BIT && !PARISC)
277	default 2048 if 64BIT
278	help
279	  Tell gcc to warn at build time for stack frames larger than this.
280	  Setting this too low will cause a lot of warnings.
281	  Setting it to 0 disables the warning.
282
283config STRIP_ASM_SYMS
284	bool "Strip assembler-generated symbols during link"
285	default n
286	help
287	  Strip internal assembler-generated symbols during a link (symbols
288	  that look like '.Lxxx') so they don't pollute the output of
289	  get_wchan() and suchlike.
290
291config READABLE_ASM
292	bool "Generate readable assembler code"
293	depends on DEBUG_KERNEL
294	help
295	  Disable some compiler optimizations that tend to generate human unreadable
296	  assembler output. This may make the kernel slightly slower, but it helps
297	  to keep kernel developers who have to stare a lot at assembler listings
298	  sane.
299
300config HEADERS_INSTALL
301	bool "Install uapi headers to usr/include"
302	depends on !UML
303	help
304	  This option will install uapi headers (headers exported to user-space)
305	  into the usr/include directory for use during the kernel build.
306	  This is unneeded for building the kernel itself, but needed for some
307	  user-space program samples. It is also needed by some features such
308	  as uapi header sanity checks.
309
310config DEBUG_SECTION_MISMATCH
311	bool "Enable full Section mismatch analysis"
312	help
313	  The section mismatch analysis checks if there are illegal
314	  references from one section to another section.
315	  During linktime or runtime, some sections are dropped;
316	  any use of code/data previously in these sections would
317	  most likely result in an oops.
318	  In the code, functions and variables are annotated with
319	  __init,, etc. (see the full list in include/linux/init.h),
320	  which results in the code/data being placed in specific sections.
321	  The section mismatch analysis is always performed after a full
322	  kernel build, and enabling this option causes the following
323	  additional step to occur:
324	  - Add the option -fno-inline-functions-called-once to gcc commands.
325	    When inlining a function annotated with __init in a non-init
326	    function, we would lose the section information and thus
327	    the analysis would not catch the illegal reference.
328	    This option tells gcc to inline less (but it does result in
329	    a larger kernel).
330
331config SECTION_MISMATCH_WARN_ONLY
332	bool "Make section mismatch errors non-fatal"
333	default y
334	help
335	  If you say N here, the build process will fail if there are any
336	  section mismatch, instead of just throwing warnings.
337
338	  If unsure, say Y.
339
340#
341# Select this config option from the architecture Kconfig, if it
342# is preferred to always offer frame pointers as a config
343# option on the architecture (regardless of KERNEL_DEBUG):
344#
345config ARCH_WANT_FRAME_POINTERS
346	bool
347
348config FRAME_POINTER
349	bool "Compile the kernel with frame pointers"
350	depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
351	default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
352	help
353	  If you say Y here the resulting kernel image will be slightly
354	  larger and slower, but it gives very useful debugging information
355	  in case of kernel bugs. (precise oopses/stacktraces/warnings)
356
357config STACK_VALIDATION
358	bool "Compile-time stack metadata validation"
359	depends on HAVE_STACK_VALIDATION
360	default n
361	help
362	  Add compile-time checks to validate stack metadata, including frame
363	  pointers (if CONFIG_FRAME_POINTER is enabled).  This helps ensure
364	  that runtime stack traces are more reliable.
365
366	  This is also a prerequisite for generation of ORC unwind data, which
367	  is needed for CONFIG_UNWINDER_ORC.
368
369	  For more information, see
370	  tools/objtool/Documentation/stack-validation.txt.
371
372config DEBUG_FORCE_WEAK_PER_CPU
373	bool "Force weak per-cpu definitions"
374	depends on DEBUG_KERNEL
375	help
376	  s390 and alpha require percpu variables in modules to be
377	  defined weak to work around addressing range issue which
378	  puts the following two restrictions on percpu variable
379	  definitions.
380
381	  1. percpu symbols must be unique whether static or not
382	  2. percpu variables can't be defined inside a function
383
384	  To ensure that generic code follows the above rules, this
385	  option forces all percpu variables to be defined as weak.
386
387endmenu # "Compiler options"
388
389menu "Generic Kernel Debugging Instruments"
390
391config MAGIC_SYSRQ
392	bool "Magic SysRq key"
393	depends on !UML
394	help
395	  If you say Y here, you will have some control over the system even
396	  if the system crashes for example during kernel debugging (e.g., you
397	  will be able to flush the buffer cache to disk, reboot the system
398	  immediately or dump some status information). This is accomplished
399	  by pressing various keys while holding SysRq (Alt+PrintScreen). It
400	  also works on a serial console (on PC hardware at least), if you
401	  send a BREAK and then within 5 seconds a command keypress. The
402	  keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
403	  Don't say Y unless you really know what this hack does.
404
405config MAGIC_SYSRQ_DEFAULT_ENABLE
406	hex "Enable magic SysRq key functions by default"
407	depends on MAGIC_SYSRQ
408	default 0x1
409	help
410	  Specifies which SysRq key functions are enabled by default.
411	  This may be set to 1 or 0 to enable or disable them all, or
412	  to a bitmask as described in Documentation/admin-guide/sysrq.rst.
413
414config MAGIC_SYSRQ_SERIAL
415	bool "Enable magic SysRq key over serial"
416	depends on MAGIC_SYSRQ
417	default y
418	help
419	  Many embedded boards have a disconnected TTL level serial which can
420	  generate some garbage that can lead to spurious false sysrq detects.
421	  This option allows you to decide whether you want to enable the
422	  magic SysRq key.
423
424config MAGIC_SYSRQ_SERIAL_SEQUENCE
425	string "Char sequence that enables magic SysRq over serial"
426	depends on MAGIC_SYSRQ_SERIAL
427	default ""
428	help
429	  Specifies a sequence of characters that can follow BREAK to enable
430	  SysRq on a serial console.
431
432	  If unsure, leave an empty string and the option will not be enabled.
433
434config DEBUG_FS
435	bool "Debug Filesystem"
436	help
437	  debugfs is a virtual file system that kernel developers use to put
438	  debugging files into.  Enable this option to be able to read and
439	  write to these files.
440
441	  For detailed documentation on the debugfs API, see
442	  Documentation/filesystems/.
443
444	  If unsure, say N.
445
446source "lib/Kconfig.kgdb"
447
448source "lib/Kconfig.ubsan"
449
450endmenu
451
452config DEBUG_KERNEL
453	bool "Kernel debugging"
454	help
455	  Say Y here if you are developing drivers or trying to debug and
456	  identify kernel problems.
457
458config DEBUG_MISC
459	bool "Miscellaneous debug code"
460	default DEBUG_KERNEL
461	depends on DEBUG_KERNEL
462	help
463	  Say Y here if you need to enable miscellaneous debug code that should
464	  be under a more specific debug option but isn't.
465
466
467menu "Memory Debugging"
468
469source "mm/Kconfig.debug"
470
471config DEBUG_OBJECTS
472	bool "Debug object operations"
473	depends on DEBUG_KERNEL
474	help
475	  If you say Y here, additional code will be inserted into the
476	  kernel to track the life time of various objects and validate
477	  the operations on those objects.
478
479config DEBUG_OBJECTS_SELFTEST
480	bool "Debug objects selftest"
481	depends on DEBUG_OBJECTS
482	help
483	  This enables the selftest of the object debug code.
484
485config DEBUG_OBJECTS_FREE
486	bool "Debug objects in freed memory"
487	depends on DEBUG_OBJECTS
488	help
489	  This enables checks whether a k/v free operation frees an area
490	  which contains an object which has not been deactivated
491	  properly. This can make kmalloc/kfree-intensive workloads
492	  much slower.
493
494config DEBUG_OBJECTS_TIMERS
495	bool "Debug timer objects"
496	depends on DEBUG_OBJECTS
497	help
498	  If you say Y here, additional code will be inserted into the
499	  timer routines to track the life time of timer objects and
500	  validate the timer operations.
501
502config DEBUG_OBJECTS_WORK
503	bool "Debug work objects"
504	depends on DEBUG_OBJECTS
505	help
506	  If you say Y here, additional code will be inserted into the
507	  work queue routines to track the life time of work objects and
508	  validate the work operations.
509
510config DEBUG_OBJECTS_RCU_HEAD
511	bool "Debug RCU callbacks objects"
512	depends on DEBUG_OBJECTS
513	help
514	  Enable this to turn on debugging of RCU list heads (call_rcu() usage).
515
516config DEBUG_OBJECTS_PERCPU_COUNTER
517	bool "Debug percpu counter objects"
518	depends on DEBUG_OBJECTS
519	help
520	  If you say Y here, additional code will be inserted into the
521	  percpu counter routines to track the life time of percpu counter
522	  objects and validate the percpu counter operations.
523
524config DEBUG_OBJECTS_ENABLE_DEFAULT
525	int "debug_objects bootup default value (0-1)"
526	range 0 1
527	default "1"
528	depends on DEBUG_OBJECTS
529	help
530	  Debug objects boot parameter default value
531
532config DEBUG_SLAB
533	bool "Debug slab memory allocations"
534	depends on DEBUG_KERNEL && SLAB
535	help
536	  Say Y here to have the kernel do limited verification on memory
537	  allocation as well as poisoning memory on free to catch use of freed
538	  memory. This can make kmalloc/kfree-intensive workloads much slower.
539
540config SLUB_DEBUG_ON
541	bool "SLUB debugging on by default"
542	depends on SLUB && SLUB_DEBUG
543	default n
544	help
545	  Boot with debugging on by default. SLUB boots by default with
546	  the runtime debug capabilities switched off. Enabling this is
547	  equivalent to specifying the "slub_debug" parameter on boot.
548	  There is no support for more fine grained debug control like
549	  possible with slub_debug=xxx. SLUB debugging may be switched
550	  off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
551	  "slub_debug=-".
552
553config SLUB_STATS
554	default n
555	bool "Enable SLUB performance statistics"
556	depends on SLUB && SYSFS
557	help
558	  SLUB statistics are useful to debug SLUBs allocation behavior in
559	  order find ways to optimize the allocator. This should never be
560	  enabled for production use since keeping statistics slows down
561	  the allocator by a few percentage points. The slabinfo command
562	  supports the determination of the most active slabs to figure
563	  out which slabs are relevant to a particular load.
564	  Try running: slabinfo -DA
565
566config HAVE_DEBUG_KMEMLEAK
567	bool
568
569config DEBUG_KMEMLEAK
570	bool "Kernel memory leak detector"
571	depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
572	select DEBUG_FS
573	select STACKTRACE if STACKTRACE_SUPPORT
574	select KALLSYMS
575	select CRC32
576	help
577	  Say Y here if you want to enable the memory leak
578	  detector. The memory allocation/freeing is traced in a way
579	  similar to the Boehm's conservative garbage collector, the
580	  difference being that the orphan objects are not freed but
581	  only shown in /sys/kernel/debug/kmemleak. Enabling this
582	  feature will introduce an overhead to memory
583	  allocations. See Documentation/dev-tools/kmemleak.rst for more
584	  details.
585
586	  Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
587	  of finding leaks due to the slab objects poisoning.
588
589	  In order to access the kmemleak file, debugfs needs to be
590	  mounted (usually at /sys/kernel/debug).
591
592config DEBUG_KMEMLEAK_MEM_POOL_SIZE
593	int "Kmemleak memory pool size"
594	depends on DEBUG_KMEMLEAK
595	range 200 1000000
596	default 16000
597	help
598	  Kmemleak must track all the memory allocations to avoid
599	  reporting false positives. Since memory may be allocated or
600	  freed before kmemleak is fully initialised, use a static pool
601	  of metadata objects to track such callbacks. After kmemleak is
602	  fully initialised, this memory pool acts as an emergency one
603	  if slab allocations fail.
604
605config DEBUG_KMEMLEAK_TEST
606	tristate "Simple test for the kernel memory leak detector"
607	depends on DEBUG_KMEMLEAK && m
608	help
609	  This option enables a module that explicitly leaks memory.
610
611	  If unsure, say N.
612
613config DEBUG_KMEMLEAK_DEFAULT_OFF
614	bool "Default kmemleak to off"
615	depends on DEBUG_KMEMLEAK
616	help
617	  Say Y here to disable kmemleak by default. It can then be enabled
618	  on the command line via kmemleak=on.
619
620config DEBUG_KMEMLEAK_AUTO_SCAN
621	bool "Enable kmemleak auto scan thread on boot up"
622	default y
623	depends on DEBUG_KMEMLEAK
624	help
625	  Depending on the cpu, kmemleak scan may be cpu intensive and can
626	  stall user tasks at times. This option enables/disables automatic
627	  kmemleak scan at boot up.
628
629	  Say N here to disable kmemleak auto scan thread to stop automatic
630	  scanning. Disabling this option disables automatic reporting of
631	  memory leaks.
632
633	  If unsure, say Y.
634
635config DEBUG_STACK_USAGE
636	bool "Stack utilization instrumentation"
637	depends on DEBUG_KERNEL && !IA64
638	help
639	  Enables the display of the minimum amount of free stack which each
640	  task has ever had available in the sysrq-T and sysrq-P debug output.
641
642	  This option will slow down process creation somewhat.
643
644config SCHED_STACK_END_CHECK
645	bool "Detect stack corruption on calls to schedule()"
646	depends on DEBUG_KERNEL
647	default n
648	help
649	  This option checks for a stack overrun on calls to schedule().
650	  If the stack end location is found to be over written always panic as
651	  the content of the corrupted region can no longer be trusted.
652	  This is to ensure no erroneous behaviour occurs which could result in
653	  data corruption or a sporadic crash at a later stage once the region
654	  is examined. The runtime overhead introduced is minimal.
655
656config DEBUG_VM
657	bool "Debug VM"
658	depends on DEBUG_KERNEL
659	help
660	  Enable this to turn on extended checks in the virtual-memory system
661	  that may impact performance.
662
663	  If unsure, say N.
664
665config DEBUG_VM_VMACACHE
666	bool "Debug VMA caching"
667	depends on DEBUG_VM
668	help
669	  Enable this to turn on VMA caching debug information. Doing so
670	  can cause significant overhead, so only enable it in non-production
671	  environments.
672
673	  If unsure, say N.
674
675config DEBUG_VM_RB
676	bool "Debug VM red-black trees"
677	depends on DEBUG_VM
678	help
679	  Enable VM red-black tree debugging information and extra validations.
680
681	  If unsure, say N.
682
683config DEBUG_VM_PGFLAGS
684	bool "Debug page-flags operations"
685	depends on DEBUG_VM
686	help
687	  Enables extra validation on page flags operations.
688
689	  If unsure, say N.
690
691config ARCH_HAS_DEBUG_VIRTUAL
692	bool
693
694config DEBUG_VIRTUAL
695	bool "Debug VM translations"
696	depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
697	help
698	  Enable some costly sanity checks in virtual to page code. This can
699	  catch mistakes with virt_to_page() and friends.
700
701	  If unsure, say N.
702
703config DEBUG_NOMMU_REGIONS
704	bool "Debug the global anon/private NOMMU mapping region tree"
705	depends on DEBUG_KERNEL && !MMU
706	help
707	  This option causes the global tree of anonymous and private mapping
708	  regions to be regularly checked for invalid topology.
709
710config DEBUG_MEMORY_INIT
711	bool "Debug memory initialisation" if EXPERT
712	default !EXPERT
713	help
714	  Enable this for additional checks during memory initialisation.
715	  The sanity checks verify aspects of the VM such as the memory model
716	  and other information provided by the architecture. Verbose
717	  information will be printed at KERN_DEBUG loglevel depending
718	  on the mminit_loglevel= command-line option.
719
720	  If unsure, say Y
721
722config MEMORY_NOTIFIER_ERROR_INJECT
723	tristate "Memory hotplug notifier error injection module"
724	depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
725	help
726	  This option provides the ability to inject artificial errors to
727	  memory hotplug notifier chain callbacks.  It is controlled through
728	  debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
729
730	  If the notifier call chain should be failed with some events
731	  notified, write the error code to "actions/<notifier event>/error".
732
733	  Example: Inject memory hotplug offline error (-12 == -ENOMEM)
734
735	  # cd /sys/kernel/debug/notifier-error-inject/memory
736	  # echo -12 > actions/MEM_GOING_OFFLINE/error
737	  # echo offline > /sys/devices/system/memory/memoryXXX/state
738	  bash: echo: write error: Cannot allocate memory
739
740	  To compile this code as a module, choose M here: the module will
741	  be called memory-notifier-error-inject.
742
743	  If unsure, say N.
744
745config DEBUG_PER_CPU_MAPS
746	bool "Debug access to per_cpu maps"
747	depends on DEBUG_KERNEL
748	depends on SMP
749	help
750	  Say Y to verify that the per_cpu map being accessed has
751	  been set up. This adds a fair amount of code to kernel memory
752	  and decreases performance.
753
754	  Say N if unsure.
755
756config DEBUG_HIGHMEM
757	bool "Highmem debugging"
758	depends on DEBUG_KERNEL && HIGHMEM
759	help
760	  This option enables additional error checking for high memory
761	  systems.  Disable for production systems.
762
763config HAVE_DEBUG_STACKOVERFLOW
764	bool
765
766config DEBUG_STACKOVERFLOW
767	bool "Check for stack overflows"
768	depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
769	---help---
770	  Say Y here if you want to check for overflows of kernel, IRQ
771	  and exception stacks (if your architecture uses them). This
772	  option will show detailed messages if free stack space drops
773	  below a certain limit.
774
775	  These kinds of bugs usually occur when call-chains in the
776	  kernel get too deep, especially when interrupts are
777	  involved.
778
779	  Use this in cases where you see apparently random memory
780	  corruption, especially if it appears in 'struct thread_info'
781
782	  If in doubt, say "N".
783
784source "lib/Kconfig.kasan"
785
786endmenu # "Memory Debugging"
787
788config DEBUG_SHIRQ
789	bool "Debug shared IRQ handlers"
790	depends on DEBUG_KERNEL
791	help
792	  Enable this to generate a spurious interrupt as soon as a shared
793	  interrupt handler is registered, and just before one is deregistered.
794	  Drivers ought to be able to handle interrupts coming in at those
795	  points; some don't and need to be caught.
796
797menu "Debug Oops, Lockups and Hangs"
798
799config PANIC_ON_OOPS
800	bool "Panic on Oops"
801	help
802	  Say Y here to enable the kernel to panic when it oopses. This
803	  has the same effect as setting oops=panic on the kernel command
804	  line.
805
806	  This feature is useful to ensure that the kernel does not do
807	  anything erroneous after an oops which could result in data
808	  corruption or other issues.
809
810	  Say N if unsure.
811
812config PANIC_ON_OOPS_VALUE
813	int
814	range 0 1
815	default 0 if !PANIC_ON_OOPS
816	default 1 if PANIC_ON_OOPS
817
818config PANIC_TIMEOUT
819	int "panic timeout"
820	default 0
821	help
822	  Set the timeout value (in seconds) until a reboot occurs when the
823	  the kernel panics. If n = 0, then we wait forever. A timeout
824	  value n > 0 will wait n seconds before rebooting, while a timeout
825	  value n < 0 will reboot immediately.
826
827config LOCKUP_DETECTOR
828	bool
829
830config SOFTLOCKUP_DETECTOR
831	bool "Detect Soft Lockups"
832	depends on DEBUG_KERNEL && !S390
833	select LOCKUP_DETECTOR
834	help
835	  Say Y here to enable the kernel to act as a watchdog to detect
836	  soft lockups.
837
838	  Softlockups are bugs that cause the kernel to loop in kernel
839	  mode for more than 20 seconds, without giving other tasks a
840	  chance to run.  The current stack trace is displayed upon
841	  detection and the system will stay locked up.
842
843config BOOTPARAM_SOFTLOCKUP_PANIC
844	bool "Panic (Reboot) On Soft Lockups"
845	depends on SOFTLOCKUP_DETECTOR
846	help
847	  Say Y here to enable the kernel to panic on "soft lockups",
848	  which are bugs that cause the kernel to loop in kernel
849	  mode for more than 20 seconds (configurable using the watchdog_thresh
850	  sysctl), without giving other tasks a chance to run.
851
852	  The panic can be used in combination with panic_timeout,
853	  to cause the system to reboot automatically after a
854	  lockup has been detected. This feature is useful for
855	  high-availability systems that have uptime guarantees and
856	  where a lockup must be resolved ASAP.
857
858	  Say N if unsure.
859
860config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
861	int
862	depends on SOFTLOCKUP_DETECTOR
863	range 0 1
864	default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
865	default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
866
867config HARDLOCKUP_DETECTOR_PERF
868	bool
869	select SOFTLOCKUP_DETECTOR
870
871#
872# Enables a timestamp based low pass filter to compensate for perf based
873# hard lockup detection which runs too fast due to turbo modes.
874#
875config HARDLOCKUP_CHECK_TIMESTAMP
876	bool
877
878#
879# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
880# lockup detector rather than the perf based detector.
881#
882config HARDLOCKUP_DETECTOR
883	bool "Detect Hard Lockups"
884	depends on DEBUG_KERNEL && !S390
885	depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
886	select LOCKUP_DETECTOR
887	select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
888	select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH
889	help
890	  Say Y here to enable the kernel to act as a watchdog to detect
891	  hard lockups.
892
893	  Hardlockups are bugs that cause the CPU to loop in kernel mode
894	  for more than 10 seconds, without letting other interrupts have a
895	  chance to run.  The current stack trace is displayed upon detection
896	  and the system will stay locked up.
897
898config BOOTPARAM_HARDLOCKUP_PANIC
899	bool "Panic (Reboot) On Hard Lockups"
900	depends on HARDLOCKUP_DETECTOR
901	help
902	  Say Y here to enable the kernel to panic on "hard lockups",
903	  which are bugs that cause the kernel to loop in kernel
904	  mode with interrupts disabled for more than 10 seconds (configurable
905	  using the watchdog_thresh sysctl).
906
907	  Say N if unsure.
908
909config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
910	int
911	depends on HARDLOCKUP_DETECTOR
912	range 0 1
913	default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
914	default 1 if BOOTPARAM_HARDLOCKUP_PANIC
915
916config DETECT_HUNG_TASK
917	bool "Detect Hung Tasks"
918	depends on DEBUG_KERNEL
919	default SOFTLOCKUP_DETECTOR
920	help
921	  Say Y here to enable the kernel to detect "hung tasks",
922	  which are bugs that cause the task to be stuck in
923	  uninterruptible "D" state indefinitely.
924
925	  When a hung task is detected, the kernel will print the
926	  current stack trace (which you should report), but the
927	  task will stay in uninterruptible state. If lockdep is
928	  enabled then all held locks will also be reported. This
929	  feature has negligible overhead.
930
931config DEFAULT_HUNG_TASK_TIMEOUT
932	int "Default timeout for hung task detection (in seconds)"
933	depends on DETECT_HUNG_TASK
934	default 120
935	help
936	  This option controls the default timeout (in seconds) used
937	  to determine when a task has become non-responsive and should
938	  be considered hung.
939
940	  It can be adjusted at runtime via the kernel.hung_task_timeout_secs
941	  sysctl or by writing a value to
942	  /proc/sys/kernel/hung_task_timeout_secs.
943
944	  A timeout of 0 disables the check.  The default is two minutes.
945	  Keeping the default should be fine in most cases.
946
947config BOOTPARAM_HUNG_TASK_PANIC
948	bool "Panic (Reboot) On Hung Tasks"
949	depends on DETECT_HUNG_TASK
950	help
951	  Say Y here to enable the kernel to panic on "hung tasks",
952	  which are bugs that cause the kernel to leave a task stuck
953	  in uninterruptible "D" state.
954
955	  The panic can be used in combination with panic_timeout,
956	  to cause the system to reboot automatically after a
957	  hung task has been detected. This feature is useful for
958	  high-availability systems that have uptime guarantees and
959	  where a hung tasks must be resolved ASAP.
960
961	  Say N if unsure.
962
963config BOOTPARAM_HUNG_TASK_PANIC_VALUE
964	int
965	depends on DETECT_HUNG_TASK
966	range 0 1
967	default 0 if !BOOTPARAM_HUNG_TASK_PANIC
968	default 1 if BOOTPARAM_HUNG_TASK_PANIC
969
970config WQ_WATCHDOG
971	bool "Detect Workqueue Stalls"
972	depends on DEBUG_KERNEL
973	help
974	  Say Y here to enable stall detection on workqueues.  If a
975	  worker pool doesn't make forward progress on a pending work
976	  item for over a given amount of time, 30s by default, a
977	  warning message is printed along with dump of workqueue
978	  state.  This can be configured through kernel parameter
979	  "workqueue.watchdog_thresh" and its sysfs counterpart.
980
981config TEST_LOCKUP
982	tristate "Test module to generate lockups"
983	help
984	  This builds the "test_lockup" module that helps to make sure
985	  that watchdogs and lockup detectors are working properly.
986
987	  Depending on module parameters it could emulate soft or hard
988	  lockup, "hung task", or locking arbitrary lock for a long time.
989	  Also it could generate series of lockups with cooling-down periods.
990
991	  If unsure, say N.
992
993endmenu # "Debug lockups and hangs"
994
995menu "Scheduler Debugging"
996
997config SCHED_DEBUG
998	bool "Collect scheduler debugging info"
999	depends on DEBUG_KERNEL && PROC_FS
1000	default y
1001	help
1002	  If you say Y here, the /proc/sched_debug file will be provided
1003	  that can help debug the scheduler. The runtime overhead of this
1004	  option is minimal.
1005
1006config SCHED_INFO
1007	bool
1008	default n
1009
1010config SCHEDSTATS
1011	bool "Collect scheduler statistics"
1012	depends on DEBUG_KERNEL && PROC_FS
1013	select SCHED_INFO
1014	help
1015	  If you say Y here, additional code will be inserted into the
1016	  scheduler and related routines to collect statistics about
1017	  scheduler behavior and provide them in /proc/schedstat.  These
1018	  stats may be useful for both tuning and debugging the scheduler
1019	  If you aren't debugging the scheduler or trying to tune a specific
1020	  application, you can say N to avoid the very slight overhead
1021	  this adds.
1022
1023endmenu
1024
1025config DEBUG_TIMEKEEPING
1026	bool "Enable extra timekeeping sanity checking"
1027	help
1028	  This option will enable additional timekeeping sanity checks
1029	  which may be helpful when diagnosing issues where timekeeping
1030	  problems are suspected.
1031
1032	  This may include checks in the timekeeping hotpaths, so this
1033	  option may have a (very small) performance impact to some
1034	  workloads.
1035
1036	  If unsure, say N.
1037
1038config DEBUG_PREEMPT
1039	bool "Debug preemptible kernel"
1040	depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1041	default y
1042	help
1043	  If you say Y here then the kernel will use a debug variant of the
1044	  commonly used smp_processor_id() function and will print warnings
1045	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
1046	  will detect preemption count underflows.
1047
1048menu "Lock Debugging (spinlocks, mutexes, etc...)"
1049
1050config LOCK_DEBUGGING_SUPPORT
1051	bool
1052	depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1053	default y
1054
1055config PROVE_LOCKING
1056	bool "Lock debugging: prove locking correctness"
1057	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1058	select LOCKDEP
1059	select DEBUG_SPINLOCK
1060	select DEBUG_MUTEXES
1061	select DEBUG_RT_MUTEXES if RT_MUTEXES
1062	select DEBUG_RWSEMS
1063	select DEBUG_WW_MUTEX_SLOWPATH
1064	select DEBUG_LOCK_ALLOC
1065	select TRACE_IRQFLAGS
1066	default n
1067	help
1068	 This feature enables the kernel to prove that all locking
1069	 that occurs in the kernel runtime is mathematically
1070	 correct: that under no circumstance could an arbitrary (and
1071	 not yet triggered) combination of observed locking
1072	 sequences (on an arbitrary number of CPUs, running an
1073	 arbitrary number of tasks and interrupt contexts) cause a
1074	 deadlock.
1075
1076	 In short, this feature enables the kernel to report locking
1077	 related deadlocks before they actually occur.
1078
1079	 The proof does not depend on how hard and complex a
1080	 deadlock scenario would be to trigger: how many
1081	 participant CPUs, tasks and irq-contexts would be needed
1082	 for it to trigger. The proof also does not depend on
1083	 timing: if a race and a resulting deadlock is possible
1084	 theoretically (no matter how unlikely the race scenario
1085	 is), it will be proven so and will immediately be
1086	 reported by the kernel (once the event is observed that
1087	 makes the deadlock theoretically possible).
1088
1089	 If a deadlock is impossible (i.e. the locking rules, as
1090	 observed by the kernel, are mathematically correct), the
1091	 kernel reports nothing.
1092
1093	 NOTE: this feature can also be enabled for rwlocks, mutexes
1094	 and rwsems - in which case all dependencies between these
1095	 different locking variants are observed and mapped too, and
1096	 the proof of observed correctness is also maintained for an
1097	 arbitrary combination of these separate locking variants.
1098
1099	 For more details, see Documentation/locking/lockdep-design.rst.
1100
1101config PROVE_RAW_LOCK_NESTING
1102	bool "Enable raw_spinlock - spinlock nesting checks"
1103	depends on PROVE_LOCKING
1104	default n
1105	help
1106	 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1107	 that the lock nesting rules for PREEMPT_RT enabled kernels are
1108	 not violated.
1109
1110	 NOTE: There are known nesting problems. So if you enable this
1111	 option expect lockdep splats until these problems have been fully
1112	 addressed which is work in progress. This config switch allows to
1113	 identify and analyze these problems. It will be removed and the
1114	 check permanentely enabled once the main issues have been fixed.
1115
1116	 If unsure, select N.
1117
1118config LOCK_STAT
1119	bool "Lock usage statistics"
1120	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1121	select LOCKDEP
1122	select DEBUG_SPINLOCK
1123	select DEBUG_MUTEXES
1124	select DEBUG_RT_MUTEXES if RT_MUTEXES
1125	select DEBUG_LOCK_ALLOC
1126	default n
1127	help
1128	 This feature enables tracking lock contention points
1129
1130	 For more details, see Documentation/locking/lockstat.rst
1131
1132	 This also enables lock events required by "perf lock",
1133	 subcommand of perf.
1134	 If you want to use "perf lock", you also need to turn on
1135	 CONFIG_EVENT_TRACING.
1136
1137	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1138	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1139
1140config DEBUG_RT_MUTEXES
1141	bool "RT Mutex debugging, deadlock detection"
1142	depends on DEBUG_KERNEL && RT_MUTEXES
1143	help
1144	 This allows rt mutex semantics violations and rt mutex related
1145	 deadlocks (lockups) to be detected and reported automatically.
1146
1147config DEBUG_SPINLOCK
1148	bool "Spinlock and rw-lock debugging: basic checks"
1149	depends on DEBUG_KERNEL
1150	select UNINLINE_SPIN_UNLOCK
1151	help
1152	  Say Y here and build SMP to catch missing spinlock initialization
1153	  and certain other kinds of spinlock errors commonly made.  This is
1154	  best used in conjunction with the NMI watchdog so that spinlock
1155	  deadlocks are also debuggable.
1156
1157config DEBUG_MUTEXES
1158	bool "Mutex debugging: basic checks"
1159	depends on DEBUG_KERNEL
1160	help
1161	 This feature allows mutex semantics violations to be detected and
1162	 reported.
1163
1164config DEBUG_WW_MUTEX_SLOWPATH
1165	bool "Wait/wound mutex debugging: Slowpath testing"
1166	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1167	select DEBUG_LOCK_ALLOC
1168	select DEBUG_SPINLOCK
1169	select DEBUG_MUTEXES
1170	help
1171	 This feature enables slowpath testing for w/w mutex users by
1172	 injecting additional -EDEADLK wound/backoff cases. Together with
1173	 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1174	 will test all possible w/w mutex interface abuse with the
1175	 exception of simply not acquiring all the required locks.
1176	 Note that this feature can introduce significant overhead, so
1177	 it really should not be enabled in a production or distro kernel,
1178	 even a debug kernel.  If you are a driver writer, enable it.  If
1179	 you are a distro, do not.
1180
1181config DEBUG_RWSEMS
1182	bool "RW Semaphore debugging: basic checks"
1183	depends on DEBUG_KERNEL
1184	help
1185	  This debugging feature allows mismatched rw semaphore locks
1186	  and unlocks to be detected and reported.
1187
1188config DEBUG_LOCK_ALLOC
1189	bool "Lock debugging: detect incorrect freeing of live locks"
1190	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1191	select DEBUG_SPINLOCK
1192	select DEBUG_MUTEXES
1193	select DEBUG_RT_MUTEXES if RT_MUTEXES
1194	select LOCKDEP
1195	help
1196	 This feature will check whether any held lock (spinlock, rwlock,
1197	 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1198	 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1199	 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1200	 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1201	 held during task exit.
1202
1203config LOCKDEP
1204	bool
1205	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1206	select STACKTRACE
1207	select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86
1208	select KALLSYMS
1209	select KALLSYMS_ALL
1210
1211config LOCKDEP_SMALL
1212	bool
1213
1214config DEBUG_LOCKDEP
1215	bool "Lock dependency engine debugging"
1216	depends on DEBUG_KERNEL && LOCKDEP
1217	help
1218	  If you say Y here, the lock dependency engine will do
1219	  additional runtime checks to debug itself, at the price
1220	  of more runtime overhead.
1221
1222config DEBUG_ATOMIC_SLEEP
1223	bool "Sleep inside atomic section checking"
1224	select PREEMPT_COUNT
1225	depends on DEBUG_KERNEL
1226	depends on !ARCH_NO_PREEMPT
1227	help
1228	  If you say Y here, various routines which may sleep will become very
1229	  noisy if they are called inside atomic sections: when a spinlock is
1230	  held, inside an rcu read side critical section, inside preempt disabled
1231	  sections, inside an interrupt, etc...
1232
1233config DEBUG_LOCKING_API_SELFTESTS
1234	bool "Locking API boot-time self-tests"
1235	depends on DEBUG_KERNEL
1236	help
1237	  Say Y here if you want the kernel to run a short self-test during
1238	  bootup. The self-test checks whether common types of locking bugs
1239	  are detected by debugging mechanisms or not. (if you disable
1240	  lock debugging then those bugs wont be detected of course.)
1241	  The following locking APIs are covered: spinlocks, rwlocks,
1242	  mutexes and rwsems.
1243
1244config LOCK_TORTURE_TEST
1245	tristate "torture tests for locking"
1246	depends on DEBUG_KERNEL
1247	select TORTURE_TEST
1248	help
1249	  This option provides a kernel module that runs torture tests
1250	  on kernel locking primitives.  The kernel module may be built
1251	  after the fact on the running kernel to be tested, if desired.
1252
1253	  Say Y here if you want kernel locking-primitive torture tests
1254	  to be built into the kernel.
1255	  Say M if you want these torture tests to build as a module.
1256	  Say N if you are unsure.
1257
1258config WW_MUTEX_SELFTEST
1259	tristate "Wait/wound mutex selftests"
1260	help
1261	  This option provides a kernel module that runs tests on the
1262	  on the struct ww_mutex locking API.
1263
1264	  It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1265	  with this test harness.
1266
1267	  Say M if you want these self tests to build as a module.
1268	  Say N if you are unsure.
1269
1270endmenu # lock debugging
1271
1272config TRACE_IRQFLAGS
1273	bool
1274	help
1275	  Enables hooks to interrupt enabling and disabling for
1276	  either tracing or lock debugging.
1277
1278config STACKTRACE
1279	bool "Stack backtrace support"
1280	depends on STACKTRACE_SUPPORT
1281	help
1282	  This option causes the kernel to create a /proc/pid/stack for
1283	  every process, showing its current stack trace.
1284	  It is also used by various kernel debugging features that require
1285	  stack trace generation.
1286
1287config WARN_ALL_UNSEEDED_RANDOM
1288	bool "Warn for all uses of unseeded randomness"
1289	default n
1290	help
1291	  Some parts of the kernel contain bugs relating to their use of
1292	  cryptographically secure random numbers before it's actually possible
1293	  to generate those numbers securely. This setting ensures that these
1294	  flaws don't go unnoticed, by enabling a message, should this ever
1295	  occur. This will allow people with obscure setups to know when things
1296	  are going wrong, so that they might contact developers about fixing
1297	  it.
1298
1299	  Unfortunately, on some models of some architectures getting
1300	  a fully seeded CRNG is extremely difficult, and so this can
1301	  result in dmesg getting spammed for a surprisingly long
1302	  time.  This is really bad from a security perspective, and
1303	  so architecture maintainers really need to do what they can
1304	  to get the CRNG seeded sooner after the system is booted.
1305	  However, since users cannot do anything actionable to
1306	  address this, by default the kernel will issue only a single
1307	  warning for the first use of unseeded randomness.
1308
1309	  Say Y here if you want to receive warnings for all uses of
1310	  unseeded randomness.  This will be of use primarily for
1311	  those developers interested in improving the security of
1312	  Linux kernels running on their architecture (or
1313	  subarchitecture).
1314
1315config DEBUG_KOBJECT
1316	bool "kobject debugging"
1317	depends on DEBUG_KERNEL
1318	help
1319	  If you say Y here, some extra kobject debugging messages will be sent
1320	  to the syslog.
1321
1322config DEBUG_KOBJECT_RELEASE
1323	bool "kobject release debugging"
1324	depends on DEBUG_OBJECTS_TIMERS
1325	help
1326	  kobjects are reference counted objects.  This means that their
1327	  last reference count put is not predictable, and the kobject can
1328	  live on past the point at which a driver decides to drop it's
1329	  initial reference to the kobject gained on allocation.  An
1330	  example of this would be a struct device which has just been
1331	  unregistered.
1332
1333	  However, some buggy drivers assume that after such an operation,
1334	  the memory backing the kobject can be immediately freed.  This
1335	  goes completely against the principles of a refcounted object.
1336
1337	  If you say Y here, the kernel will delay the release of kobjects
1338	  on the last reference count to improve the visibility of this
1339	  kind of kobject release bug.
1340
1341config HAVE_DEBUG_BUGVERBOSE
1342	bool
1343
1344menu "Debug kernel data structures"
1345
1346config DEBUG_LIST
1347	bool "Debug linked list manipulation"
1348	depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1349	help
1350	  Enable this to turn on extended checks in the linked-list
1351	  walking routines.
1352
1353	  If unsure, say N.
1354
1355config DEBUG_PLIST
1356	bool "Debug priority linked list manipulation"
1357	depends on DEBUG_KERNEL
1358	help
1359	  Enable this to turn on extended checks in the priority-ordered
1360	  linked-list (plist) walking routines.  This checks the entire
1361	  list multiple times during each manipulation.
1362
1363	  If unsure, say N.
1364
1365config DEBUG_SG
1366	bool "Debug SG table operations"
1367	depends on DEBUG_KERNEL
1368	help
1369	  Enable this to turn on checks on scatter-gather tables. This can
1370	  help find problems with drivers that do not properly initialize
1371	  their sg tables.
1372
1373	  If unsure, say N.
1374
1375config DEBUG_NOTIFIERS
1376	bool "Debug notifier call chains"
1377	depends on DEBUG_KERNEL
1378	help
1379	  Enable this to turn on sanity checking for notifier call chains.
1380	  This is most useful for kernel developers to make sure that
1381	  modules properly unregister themselves from notifier chains.
1382	  This is a relatively cheap check but if you care about maximum
1383	  performance, say N.
1384
1385config BUG_ON_DATA_CORRUPTION
1386	bool "Trigger a BUG when data corruption is detected"
1387	select DEBUG_LIST
1388	help
1389	  Select this option if the kernel should BUG when it encounters
1390	  data corruption in kernel memory structures when they get checked
1391	  for validity.
1392
1393	  If unsure, say N.
1394
1395endmenu
1396
1397config DEBUG_CREDENTIALS
1398	bool "Debug credential management"
1399	depends on DEBUG_KERNEL
1400	help
1401	  Enable this to turn on some debug checking for credential
1402	  management.  The additional code keeps track of the number of
1403	  pointers from task_structs to any given cred struct, and checks to
1404	  see that this number never exceeds the usage count of the cred
1405	  struct.
1406
1407	  Furthermore, if SELinux is enabled, this also checks that the
1408	  security pointer in the cred struct is never seen to be invalid.
1409
1410	  If unsure, say N.
1411
1412source "kernel/rcu/Kconfig.debug"
1413
1414config DEBUG_WQ_FORCE_RR_CPU
1415	bool "Force round-robin CPU selection for unbound work items"
1416	depends on DEBUG_KERNEL
1417	default n
1418	help
1419	  Workqueue used to implicitly guarantee that work items queued
1420	  without explicit CPU specified are put on the local CPU.  This
1421	  guarantee is no longer true and while local CPU is still
1422	  preferred work items may be put on foreign CPUs.  Kernel
1423	  parameter "workqueue.debug_force_rr_cpu" is added to force
1424	  round-robin CPU selection to flush out usages which depend on the
1425	  now broken guarantee.  This config option enables the debug
1426	  feature by default.  When enabled, memory and cache locality will
1427	  be impacted.
1428
1429config DEBUG_BLOCK_EXT_DEVT
1430	bool "Force extended block device numbers and spread them"
1431	depends on DEBUG_KERNEL
1432	depends on BLOCK
1433	default n
1434	help
1435	  BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1436	  SOME DISTRIBUTIONS.  DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1437	  YOU ARE DOING.  Distros, please enable this and fix whatever
1438	  is broken.
1439
1440	  Conventionally, block device numbers are allocated from
1441	  predetermined contiguous area.  However, extended block area
1442	  may introduce non-contiguous block device numbers.  This
1443	  option forces most block device numbers to be allocated from
1444	  the extended space and spreads them to discover kernel or
1445	  userland code paths which assume predetermined contiguous
1446	  device number allocation.
1447
1448	  Note that turning on this debug option shuffles all the
1449	  device numbers for all IDE and SCSI devices including libata
1450	  ones, so root partition specified using device number
1451	  directly (via rdev or root=MAJ:MIN) won't work anymore.
1452	  Textual device names (root=/dev/sdXn) will continue to work.
1453
1454	  Say N if you are unsure.
1455
1456config CPU_HOTPLUG_STATE_CONTROL
1457	bool "Enable CPU hotplug state control"
1458	depends on DEBUG_KERNEL
1459	depends on HOTPLUG_CPU
1460	default n
1461	help
1462	  Allows to write steps between "offline" and "online" to the CPUs
1463	  sysfs target file so states can be stepped granular. This is a debug
1464	  option for now as the hotplug machinery cannot be stopped and
1465	  restarted at arbitrary points yet.
1466
1467	  Say N if your are unsure.
1468
1469config LATENCYTOP
1470	bool "Latency measuring infrastructure"
1471	depends on DEBUG_KERNEL
1472	depends on STACKTRACE_SUPPORT
1473	depends on PROC_FS
1474	select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
1475	select KALLSYMS
1476	select KALLSYMS_ALL
1477	select STACKTRACE
1478	select SCHEDSTATS
1479	select SCHED_DEBUG
1480	help
1481	  Enable this option if you want to use the LatencyTOP tool
1482	  to find out which userspace is blocking on what kernel operations.
1483
1484source "kernel/trace/Kconfig"
1485
1486config PROVIDE_OHCI1394_DMA_INIT
1487	bool "Remote debugging over FireWire early on boot"
1488	depends on PCI && X86
1489	help
1490	  If you want to debug problems which hang or crash the kernel early
1491	  on boot and the crashing machine has a FireWire port, you can use
1492	  this feature to remotely access the memory of the crashed machine
1493	  over FireWire. This employs remote DMA as part of the OHCI1394
1494	  specification which is now the standard for FireWire controllers.
1495
1496	  With remote DMA, you can monitor the printk buffer remotely using
1497	  firescope and access all memory below 4GB using fireproxy from gdb.
1498	  Even controlling a kernel debugger is possible using remote DMA.
1499
1500	  Usage:
1501
1502	  If ohci1394_dma=early is used as boot parameter, it will initialize
1503	  all OHCI1394 controllers which are found in the PCI config space.
1504
1505	  As all changes to the FireWire bus such as enabling and disabling
1506	  devices cause a bus reset and thereby disable remote DMA for all
1507	  devices, be sure to have the cable plugged and FireWire enabled on
1508	  the debugging host before booting the debug target for debugging.
1509
1510	  This code (~1k) is freed after boot. By then, the firewire stack
1511	  in charge of the OHCI-1394 controllers should be used instead.
1512
1513	  See Documentation/debugging-via-ohci1394.txt for more information.
1514
1515source "samples/Kconfig"
1516
1517config ARCH_HAS_DEVMEM_IS_ALLOWED
1518	bool
1519
1520config STRICT_DEVMEM
1521	bool "Filter access to /dev/mem"
1522	depends on MMU && DEVMEM
1523	depends on ARCH_HAS_DEVMEM_IS_ALLOWED
1524	default y if PPC || X86 || ARM64
1525	help
1526	  If this option is disabled, you allow userspace (root) access to all
1527	  of memory, including kernel and userspace memory. Accidental
1528	  access to this is obviously disastrous, but specific access can
1529	  be used by people debugging the kernel. Note that with PAT support
1530	  enabled, even in this case there are restrictions on /dev/mem
1531	  use due to the cache aliasing requirements.
1532
1533	  If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1534	  file only allows userspace access to PCI space and the BIOS code and
1535	  data regions.  This is sufficient for dosemu and X and all common
1536	  users of /dev/mem.
1537
1538	  If in doubt, say Y.
1539
1540config IO_STRICT_DEVMEM
1541	bool "Filter I/O access to /dev/mem"
1542	depends on STRICT_DEVMEM
1543	help
1544	  If this option is disabled, you allow userspace (root) access to all
1545	  io-memory regardless of whether a driver is actively using that
1546	  range.  Accidental access to this is obviously disastrous, but
1547	  specific access can be used by people debugging kernel drivers.
1548
1549	  If this option is switched on, the /dev/mem file only allows
1550	  userspace access to *idle* io-memory ranges (see /proc/iomem) This
1551	  may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1552	  if the driver using a given range cannot be disabled.
1553
1554	  If in doubt, say Y.
1555
1556menu "$(SRCARCH) Debugging"
1557
1558source "arch/$(SRCARCH)/Kconfig.debug"
1559
1560endmenu
1561
1562menu "Kernel Testing and Coverage"
1563
1564source "lib/kunit/Kconfig"
1565
1566config NOTIFIER_ERROR_INJECTION
1567	tristate "Notifier error injection"
1568	depends on DEBUG_KERNEL
1569	select DEBUG_FS
1570	help
1571	  This option provides the ability to inject artificial errors to
1572	  specified notifier chain callbacks. It is useful to test the error
1573	  handling of notifier call chain failures.
1574
1575	  Say N if unsure.
1576
1577config PM_NOTIFIER_ERROR_INJECT
1578	tristate "PM notifier error injection module"
1579	depends on PM && NOTIFIER_ERROR_INJECTION
1580	default m if PM_DEBUG
1581	help
1582	  This option provides the ability to inject artificial errors to
1583	  PM notifier chain callbacks.  It is controlled through debugfs
1584	  interface /sys/kernel/debug/notifier-error-inject/pm
1585
1586	  If the notifier call chain should be failed with some events
1587	  notified, write the error code to "actions/<notifier event>/error".
1588
1589	  Example: Inject PM suspend error (-12 = -ENOMEM)
1590
1591	  # cd /sys/kernel/debug/notifier-error-inject/pm/
1592	  # echo -12 > actions/PM_SUSPEND_PREPARE/error
1593	  # echo mem > /sys/power/state
1594	  bash: echo: write error: Cannot allocate memory
1595
1596	  To compile this code as a module, choose M here: the module will
1597	  be called pm-notifier-error-inject.
1598
1599	  If unsure, say N.
1600
1601config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1602	tristate "OF reconfig notifier error injection module"
1603	depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1604	help
1605	  This option provides the ability to inject artificial errors to
1606	  OF reconfig notifier chain callbacks.  It is controlled
1607	  through debugfs interface under
1608	  /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1609
1610	  If the notifier call chain should be failed with some events
1611	  notified, write the error code to "actions/<notifier event>/error".
1612
1613	  To compile this code as a module, choose M here: the module will
1614	  be called of-reconfig-notifier-error-inject.
1615
1616	  If unsure, say N.
1617
1618config NETDEV_NOTIFIER_ERROR_INJECT
1619	tristate "Netdev notifier error injection module"
1620	depends on NET && NOTIFIER_ERROR_INJECTION
1621	help
1622	  This option provides the ability to inject artificial errors to
1623	  netdevice notifier chain callbacks.  It is controlled through debugfs
1624	  interface /sys/kernel/debug/notifier-error-inject/netdev
1625
1626	  If the notifier call chain should be failed with some events
1627	  notified, write the error code to "actions/<notifier event>/error".
1628
1629	  Example: Inject netdevice mtu change error (-22 = -EINVAL)
1630
1631	  # cd /sys/kernel/debug/notifier-error-inject/netdev
1632	  # echo -22 > actions/NETDEV_CHANGEMTU/error
1633	  # ip link set eth0 mtu 1024
1634	  RTNETLINK answers: Invalid argument
1635
1636	  To compile this code as a module, choose M here: the module will
1637	  be called netdev-notifier-error-inject.
1638
1639	  If unsure, say N.
1640
1641config FUNCTION_ERROR_INJECTION
1642	def_bool y
1643	depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1644
1645config FAULT_INJECTION
1646	bool "Fault-injection framework"
1647	depends on DEBUG_KERNEL
1648	help
1649	  Provide fault-injection framework.
1650	  For more details, see Documentation/fault-injection/.
1651
1652config FAILSLAB
1653	bool "Fault-injection capability for kmalloc"
1654	depends on FAULT_INJECTION
1655	depends on SLAB || SLUB
1656	help
1657	  Provide fault-injection capability for kmalloc.
1658
1659config FAIL_PAGE_ALLOC
1660	bool "Fault-injection capability for alloc_pages()"
1661	depends on FAULT_INJECTION
1662	help
1663	  Provide fault-injection capability for alloc_pages().
1664
1665config FAIL_MAKE_REQUEST
1666	bool "Fault-injection capability for disk IO"
1667	depends on FAULT_INJECTION && BLOCK
1668	help
1669	  Provide fault-injection capability for disk IO.
1670
1671config FAIL_IO_TIMEOUT
1672	bool "Fault-injection capability for faking disk interrupts"
1673	depends on FAULT_INJECTION && BLOCK
1674	help
1675	  Provide fault-injection capability on end IO handling. This
1676	  will make the block layer "forget" an interrupt as configured,
1677	  thus exercising the error handling.
1678
1679	  Only works with drivers that use the generic timeout handling,
1680	  for others it wont do anything.
1681
1682config FAIL_FUTEX
1683	bool "Fault-injection capability for futexes"
1684	select DEBUG_FS
1685	depends on FAULT_INJECTION && FUTEX
1686	help
1687	  Provide fault-injection capability for futexes.
1688
1689config FAULT_INJECTION_DEBUG_FS
1690	bool "Debugfs entries for fault-injection capabilities"
1691	depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1692	help
1693	  Enable configuration of fault-injection capabilities via debugfs.
1694
1695config FAIL_FUNCTION
1696	bool "Fault-injection capability for functions"
1697	depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1698	help
1699	  Provide function-based fault-injection capability.
1700	  This will allow you to override a specific function with a return
1701	  with given return value. As a result, function caller will see
1702	  an error value and have to handle it. This is useful to test the
1703	  error handling in various subsystems.
1704
1705config FAIL_MMC_REQUEST
1706	bool "Fault-injection capability for MMC IO"
1707	depends on FAULT_INJECTION_DEBUG_FS && MMC
1708	help
1709	  Provide fault-injection capability for MMC IO.
1710	  This will make the mmc core return data errors. This is
1711	  useful to test the error handling in the mmc block device
1712	  and to test how the mmc host driver handles retries from
1713	  the block device.
1714
1715config FAULT_INJECTION_STACKTRACE_FILTER
1716	bool "stacktrace filter for fault-injection capabilities"
1717	depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1718	depends on !X86_64
1719	select STACKTRACE
1720	select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
1721	help
1722	  Provide stacktrace filter for fault-injection capabilities
1723
1724config ARCH_HAS_KCOV
1725	bool
1726	help
1727	  An architecture should select this when it can successfully
1728	  build and run with CONFIG_KCOV. This typically requires
1729	  disabling instrumentation for some early boot code.
1730
1731config CC_HAS_SANCOV_TRACE_PC
1732	def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1733
1734
1735config KCOV
1736	bool "Code coverage for fuzzing"
1737	depends on ARCH_HAS_KCOV
1738	depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1739	select DEBUG_FS
1740	select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1741	help
1742	  KCOV exposes kernel code coverage information in a form suitable
1743	  for coverage-guided fuzzing (randomized testing).
1744
1745	  If RANDOMIZE_BASE is enabled, PC values will not be stable across
1746	  different machines and across reboots. If you need stable PC values,
1747	  disable RANDOMIZE_BASE.
1748
1749	  For more details, see Documentation/dev-tools/kcov.rst.
1750
1751config KCOV_ENABLE_COMPARISONS
1752	bool "Enable comparison operands collection by KCOV"
1753	depends on KCOV
1754	depends on $(cc-option,-fsanitize-coverage=trace-cmp)
1755	help
1756	  KCOV also exposes operands of every comparison in the instrumented
1757	  code along with operand sizes and PCs of the comparison instructions.
1758	  These operands can be used by fuzzing engines to improve the quality
1759	  of fuzzing coverage.
1760
1761config KCOV_INSTRUMENT_ALL
1762	bool "Instrument all code by default"
1763	depends on KCOV
1764	default y
1765	help
1766	  If you are doing generic system call fuzzing (like e.g. syzkaller),
1767	  then you will want to instrument the whole kernel and you should
1768	  say y here. If you are doing more targeted fuzzing (like e.g.
1769	  filesystem fuzzing with AFL) then you will want to enable coverage
1770	  for more specific subsets of files, and should say n here.
1771
1772menuconfig RUNTIME_TESTING_MENU
1773	bool "Runtime Testing"
1774	def_bool y
1775
1776if RUNTIME_TESTING_MENU
1777
1778config LKDTM
1779	tristate "Linux Kernel Dump Test Tool Module"
1780	depends on DEBUG_FS
1781	help
1782	This module enables testing of the different dumping mechanisms by
1783	inducing system failures at predefined crash points.
1784	If you don't need it: say N
1785	Choose M here to compile this code as a module. The module will be
1786	called lkdtm.
1787
1788	Documentation on how to use the module can be found in
1789	Documentation/fault-injection/provoke-crashes.rst
1790
1791config TEST_LIST_SORT
1792	tristate "Linked list sorting test"
1793	depends on DEBUG_KERNEL || m
1794	help
1795	  Enable this to turn on 'list_sort()' function test. This test is
1796	  executed only once during system boot (so affects only boot time),
1797	  or at module load time.
1798
1799	  If unsure, say N.
1800
1801config TEST_MIN_HEAP
1802	tristate "Min heap test"
1803	depends on DEBUG_KERNEL || m
1804	help
1805	  Enable this to turn on min heap function tests. This test is
1806	  executed only once during system boot (so affects only boot time),
1807	  or at module load time.
1808
1809	  If unsure, say N.
1810
1811config TEST_SORT
1812	tristate "Array-based sort test"
1813	depends on DEBUG_KERNEL || m
1814	help
1815	  This option enables the self-test function of 'sort()' at boot,
1816	  or at module load time.
1817
1818	  If unsure, say N.
1819
1820config KPROBES_SANITY_TEST
1821	bool "Kprobes sanity tests"
1822	depends on DEBUG_KERNEL
1823	depends on KPROBES
1824	help
1825	  This option provides for testing basic kprobes functionality on
1826	  boot. Samples of kprobe and kretprobe are inserted and
1827	  verified for functionality.
1828
1829	  Say N if you are unsure.
1830
1831config BACKTRACE_SELF_TEST
1832	tristate "Self test for the backtrace code"
1833	depends on DEBUG_KERNEL
1834	help
1835	  This option provides a kernel module that can be used to test
1836	  the kernel stack backtrace code. This option is not useful
1837	  for distributions or general kernels, but only for kernel
1838	  developers working on architecture code.
1839
1840	  Note that if you want to also test saved backtraces, you will
1841	  have to enable STACKTRACE as well.
1842
1843	  Say N if you are unsure.
1844
1845config RBTREE_TEST
1846	tristate "Red-Black tree test"
1847	depends on DEBUG_KERNEL
1848	help
1849	  A benchmark measuring the performance of the rbtree library.
1850	  Also includes rbtree invariant checks.
1851
1852config REED_SOLOMON_TEST
1853	tristate "Reed-Solomon library test"
1854	depends on DEBUG_KERNEL || m
1855	select REED_SOLOMON
1856	select REED_SOLOMON_ENC16
1857	select REED_SOLOMON_DEC16
1858	help
1859	  This option enables the self-test function of rslib at boot,
1860	  or at module load time.
1861
1862	  If unsure, say N.
1863
1864config INTERVAL_TREE_TEST
1865	tristate "Interval tree test"
1866	depends on DEBUG_KERNEL
1867	select INTERVAL_TREE
1868	help
1869	  A benchmark measuring the performance of the interval tree library
1870
1871config PERCPU_TEST
1872	tristate "Per cpu operations test"
1873	depends on m && DEBUG_KERNEL
1874	help
1875	  Enable this option to build test module which validates per-cpu
1876	  operations.
1877
1878	  If unsure, say N.
1879
1880config ATOMIC64_SELFTEST
1881	tristate "Perform an atomic64_t self-test"
1882	help
1883	  Enable this option to test the atomic64_t functions at boot or
1884	  at module load time.
1885
1886	  If unsure, say N.
1887
1888config ASYNC_RAID6_TEST
1889	tristate "Self test for hardware accelerated raid6 recovery"
1890	depends on ASYNC_RAID6_RECOV
1891	select ASYNC_MEMCPY
1892	---help---
1893	  This is a one-shot self test that permutes through the
1894	  recovery of all the possible two disk failure scenarios for a
1895	  N-disk array.  Recovery is performed with the asynchronous
1896	  raid6 recovery routines, and will optionally use an offload
1897	  engine if one is available.
1898
1899	  If unsure, say N.
1900
1901config TEST_HEXDUMP
1902	tristate "Test functions located in the hexdump module at runtime"
1903
1904config TEST_STRING_HELPERS
1905	tristate "Test functions located in the string_helpers module at runtime"
1906
1907config TEST_STRSCPY
1908	tristate "Test strscpy*() family of functions at runtime"
1909
1910config TEST_KSTRTOX
1911	tristate "Test kstrto*() family of functions at runtime"
1912
1913config TEST_PRINTF
1914	tristate "Test printf() family of functions at runtime"
1915
1916config TEST_BITMAP
1917	tristate "Test bitmap_*() family of functions at runtime"
1918	help
1919	  Enable this option to test the bitmap functions at boot.
1920
1921	  If unsure, say N.
1922
1923config TEST_BITFIELD
1924	tristate "Test bitfield functions at runtime"
1925	help
1926	  Enable this option to test the bitfield functions at boot.
1927
1928	  If unsure, say N.
1929
1930config TEST_UUID
1931	tristate "Test functions located in the uuid module at runtime"
1932
1933config TEST_XARRAY
1934	tristate "Test the XArray code at runtime"
1935
1936config TEST_OVERFLOW
1937	tristate "Test check_*_overflow() functions at runtime"
1938
1939config TEST_RHASHTABLE
1940	tristate "Perform selftest on resizable hash table"
1941	help
1942	  Enable this option to test the rhashtable functions at boot.
1943
1944	  If unsure, say N.
1945
1946config TEST_HASH
1947	tristate "Perform selftest on hash functions"
1948	help
1949	  Enable this option to test the kernel's integer (<linux/hash.h>),
1950	  string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
1951	  hash functions on boot (or module load).
1952
1953	  This is intended to help people writing architecture-specific
1954	  optimized versions.  If unsure, say N.
1955
1956config TEST_IDA
1957	tristate "Perform selftest on IDA functions"
1958
1959config TEST_PARMAN
1960	tristate "Perform selftest on priority array manager"
1961	depends on PARMAN
1962	help
1963	  Enable this option to test priority array manager on boot
1964	  (or module load).
1965
1966	  If unsure, say N.
1967
1968config TEST_IRQ_TIMINGS
1969	bool "IRQ timings selftest"
1970	depends on IRQ_TIMINGS
1971	help
1972	  Enable this option to test the irq timings code on boot.
1973
1974	  If unsure, say N.
1975
1976config TEST_LKM
1977	tristate "Test module loading with 'hello world' module"
1978	depends on m
1979	help
1980	  This builds the "test_module" module that emits "Hello, world"
1981	  on printk when loaded. It is designed to be used for basic
1982	  evaluation of the module loading subsystem (for example when
1983	  validating module verification). It lacks any extra dependencies,
1984	  and will not normally be loaded by the system unless explicitly
1985	  requested by name.
1986
1987	  If unsure, say N.
1988
1989config TEST_VMALLOC
1990	tristate "Test module for stress/performance analysis of vmalloc allocator"
1991	default n
1992       depends on MMU
1993	depends on m
1994	help
1995	  This builds the "test_vmalloc" module that should be used for
1996	  stress and performance analysis. So, any new change for vmalloc
1997	  subsystem can be evaluated from performance and stability point
1998	  of view.
1999
2000	  If unsure, say N.
2001
2002config TEST_USER_COPY
2003	tristate "Test user/kernel boundary protections"
2004	depends on m
2005	help
2006	  This builds the "test_user_copy" module that runs sanity checks
2007	  on the copy_to/from_user infrastructure, making sure basic
2008	  user/kernel boundary testing is working. If it fails to load,
2009	  a regression has been detected in the user/kernel memory boundary
2010	  protections.
2011
2012	  If unsure, say N.
2013
2014config TEST_BPF
2015	tristate "Test BPF filter functionality"
2016	depends on m && NET
2017	help
2018	  This builds the "test_bpf" module that runs various test vectors
2019	  against the BPF interpreter or BPF JIT compiler depending on the
2020	  current setting. This is in particular useful for BPF JIT compiler
2021	  development, but also to run regression tests against changes in
2022	  the interpreter code. It also enables test stubs for eBPF maps and
2023	  verifier used by user space verifier testsuite.
2024
2025	  If unsure, say N.
2026
2027config TEST_BLACKHOLE_DEV
2028	tristate "Test blackhole netdev functionality"
2029	depends on m && NET
2030	help
2031	  This builds the "test_blackhole_dev" module that validates the
2032	  data path through this blackhole netdev.
2033
2034	  If unsure, say N.
2035
2036config FIND_BIT_BENCHMARK
2037	tristate "Test find_bit functions"
2038	help
2039	  This builds the "test_find_bit" module that measure find_*_bit()
2040	  functions performance.
2041
2042	  If unsure, say N.
2043
2044config TEST_FIRMWARE
2045	tristate "Test firmware loading via userspace interface"
2046	depends on FW_LOADER
2047	help
2048	  This builds the "test_firmware" module that creates a userspace
2049	  interface for testing firmware loading. This can be used to
2050	  control the triggering of firmware loading without needing an
2051	  actual firmware-using device. The contents can be rechecked by
2052	  userspace.
2053
2054	  If unsure, say N.
2055
2056config TEST_SYSCTL
2057	tristate "sysctl test driver"
2058	depends on PROC_SYSCTL
2059	help
2060	  This builds the "test_sysctl" module. This driver enables to test the
2061	  proc sysctl interfaces available to drivers safely without affecting
2062	  production knobs which might alter system functionality.
2063
2064	  If unsure, say N.
2065
2066config SYSCTL_KUNIT_TEST
2067	tristate "KUnit test for sysctl"
2068	depends on KUNIT
2069	help
2070	  This builds the proc sysctl unit test, which runs on boot.
2071	  Tests the API contract and implementation correctness of sysctl.
2072	  For more information on KUnit and unit tests in general please refer
2073	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2074
2075	  If unsure, say N.
2076
2077config LIST_KUNIT_TEST
2078	tristate "KUnit Test for Kernel Linked-list structures"
2079	depends on KUNIT
2080	help
2081	  This builds the linked list KUnit test suite.
2082	  It tests that the API and basic functionality of the list_head type
2083	  and associated macros.
2084
2085	  KUnit tests run during boot and output the results to the debug log
2086	  in TAP format (http://testanything.org/). Only useful for kernel devs
2087	  running the KUnit test harness, and not intended for inclusion into a
2088	  production build.
2089
2090	  For more information on KUnit and unit tests in general please refer
2091	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2092
2093	  If unsure, say N.
2094
2095config LINEAR_RANGES_TEST
2096	tristate "KUnit test for linear_ranges"
2097	depends on KUNIT
2098	select LINEAR_RANGES
2099	help
2100	  This builds the linear_ranges unit test, which runs on boot.
2101	  Tests the linear_ranges logic correctness.
2102	  For more information on KUnit and unit tests in general please refer
2103	  to the KUnit documentation in Documentation/dev-tools/kunit/.
2104
2105	  If unsure, say N.
2106
2107config TEST_UDELAY
2108	tristate "udelay test driver"
2109	help
2110	  This builds the "udelay_test" module that helps to make sure
2111	  that udelay() is working properly.
2112
2113	  If unsure, say N.
2114
2115config TEST_STATIC_KEYS
2116	tristate "Test static keys"
2117	depends on m
2118	help
2119	  Test the static key interfaces.
2120
2121	  If unsure, say N.
2122
2123config TEST_KMOD
2124	tristate "kmod stress tester"
2125	depends on m
2126	depends on NETDEVICES && NET_CORE && INET # for TUN
2127	depends on BLOCK
2128	select TEST_LKM
2129	select XFS_FS
2130	select TUN
2131	select BTRFS_FS
2132	help
2133	  Test the kernel's module loading mechanism: kmod. kmod implements
2134	  support to load modules using the Linux kernel's usermode helper.
2135	  This test provides a series of tests against kmod.
2136
2137	  Although technically you can either build test_kmod as a module or
2138	  into the kernel we disallow building it into the kernel since
2139	  it stress tests request_module() and this will very likely cause
2140	  some issues by taking over precious threads available from other
2141	  module load requests, ultimately this could be fatal.
2142
2143	  To run tests run:
2144
2145	  tools/testing/selftests/kmod/kmod.sh --help
2146
2147	  If unsure, say N.
2148
2149config TEST_DEBUG_VIRTUAL
2150	tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2151	depends on DEBUG_VIRTUAL
2152	help
2153	  Test the kernel's ability to detect incorrect calls to
2154	  virt_to_phys() done against the non-linear part of the
2155	  kernel's virtual address map.
2156
2157	  If unsure, say N.
2158
2159config TEST_MEMCAT_P
2160	tristate "Test memcat_p() helper function"
2161	help
2162	  Test the memcat_p() helper for correctly merging two
2163	  pointer arrays together.
2164
2165	  If unsure, say N.
2166
2167config TEST_LIVEPATCH
2168	tristate "Test livepatching"
2169	default n
2170	depends on DYNAMIC_DEBUG
2171	depends on LIVEPATCH
2172	depends on m
2173	help
2174	  Test kernel livepatching features for correctness.  The tests will
2175	  load test modules that will be livepatched in various scenarios.
2176
2177	  To run all the livepatching tests:
2178
2179	  make -C tools/testing/selftests TARGETS=livepatch run_tests
2180
2181	  Alternatively, individual tests may be invoked:
2182
2183	  tools/testing/selftests/livepatch/test-callbacks.sh
2184	  tools/testing/selftests/livepatch/test-livepatch.sh
2185	  tools/testing/selftests/livepatch/test-shadow-vars.sh
2186
2187	  If unsure, say N.
2188
2189config TEST_OBJAGG
2190	tristate "Perform selftest on object aggreration manager"
2191	default n
2192	depends on OBJAGG
2193	help
2194	  Enable this option to test object aggregation manager on boot
2195	  (or module load).
2196
2197
2198config TEST_STACKINIT
2199	tristate "Test level of stack variable initialization"
2200	help
2201	  Test if the kernel is zero-initializing stack variables and
2202	  padding. Coverage is controlled by compiler flags,
2203	  CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2204	  or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2205
2206	  If unsure, say N.
2207
2208config TEST_MEMINIT
2209	tristate "Test heap/page initialization"
2210	help
2211	  Test if the kernel is zero-initializing heap and page allocations.
2212	  This can be useful to test init_on_alloc and init_on_free features.
2213
2214	  If unsure, say N.
2215
2216endif # RUNTIME_TESTING_MENU
2217
2218config MEMTEST
2219	bool "Memtest"
2220	---help---
2221	  This option adds a kernel parameter 'memtest', which allows memtest
2222	  to be set.
2223	        memtest=0, mean disabled; -- default
2224	        memtest=1, mean do 1 test pattern;
2225	        ...
2226	        memtest=17, mean do 17 test patterns.
2227	  If you are unsure how to answer this question, answer N.
2228
2229
2230
2231config HYPERV_TESTING
2232	bool "Microsoft Hyper-V driver testing"
2233	default n
2234	depends on HYPERV && DEBUG_FS
2235	help
2236	  Select this option to enable Hyper-V vmbus testing.
2237
2238endmenu # "Kernel Testing and Coverage"
2239
2240endmenu # Kernel hacking
2241