1 # SPDX-License-Identifier: GPL-2.0-only
4 menu "printk and dmesg options"
7 bool "Show timing information on printks"
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.
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.
18 The behavior is also controlled by the kernel command line
19 parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
22 bool "Show caller information on printks"
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)
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.
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
38 config STACKTRACE_BUILD_ID
39 bool "Show build ID information in stacktraces"
42 Selecting this option adds build ID information for symbols in
43 stacktraces printed with the printk format '%p[SR]b'.
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.
49 config CONSOLE_LOGLEVEL_DEFAULT
50 int "Default console loglevel (1-15)"
54 Default loglevel to determine what will be printed on the console.
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.
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
64 config CONSOLE_LOGLEVEL_QUIET
65 int "quiet console loglevel (1-15)"
69 loglevel to use when "quiet" is passed on the kernel commandline.
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>"
75 config MESSAGE_LOGLEVEL_DEFAULT
76 int "Default message log level (1-7)"
80 Default log level for printk statements with no specified priority.
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
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.
90 config BOOT_PRINTK_DELAY
91 bool "Delay each boot printk message by N milliseconds"
92 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
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,
99 It is likely that you would also need to use "lpj=M" to preset
100 the "loops per jiffie" 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.
109 bool "Enable dynamic printk() support"
112 depends on (DEBUG_FS || PROC_FS)
113 select DYNAMIC_DEBUG_CORE
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%.
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.
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:
138 filename:lineno [module]function flags format
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
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"
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
161 // enable all the messages in file svcsock.c
162 nullarbor:~ # echo -n 'file svcsock.c +p' >
163 <debugfs>/dynamic_debug/control
165 // enable all the messages in the NFS server module
166 nullarbor:~ # echo -n 'module nfsd +p' >
167 <debugfs>/dynamic_debug/control
169 // enable all 12 messages in the function svc_process()
170 nullarbor:~ # echo -n 'func svc_process +p' >
171 <debugfs>/dynamic_debug/control
173 // disable all 12 messages in the function svc_process()
174 nullarbor:~ # echo -n 'func svc_process -p' >
175 <debugfs>/dynamic_debug/control
177 See Documentation/admin-guide/dynamic-debug-howto.rst for additional
180 config DYNAMIC_DEBUG_CORE
181 bool "Enable core function of dynamic debug support"
183 depends on (DEBUG_FS || PROC_FS)
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.
191 config SYMBOLIC_ERRNAME
192 bool "Support symbolic error names in printf"
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.
200 config DEBUG_BUGVERBOSE
201 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
202 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
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.
209 endmenu # "printk and dmesg options"
212 bool "Kernel debugging"
214 Say Y here if you are developing drivers or trying to debug and
215 identify kernel problems.
218 bool "Miscellaneous debug code"
220 depends on DEBUG_KERNEL
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.
225 menu "Compile-time checks and compiler options"
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.
235 prompt "Debug information"
236 depends on DEBUG_KERNEL
238 Selecting something other than "None" results in a kernel image
239 that will include debugging info resulting in a larger kernel image.
240 This adds debug symbols to the kernel and modules (gcc -g), and
241 is needed if you intend to use kernel crashdump or binary object
242 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
244 Choose which version of DWARF debug info to emit. If unsure,
245 select "Toolchain default".
247 config DEBUG_INFO_NONE
248 bool "Disable debug information"
250 Do not build the kernel with debugging information, which will
251 result in a faster and smaller build.
253 config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
254 bool "Rely on the toolchain's implicit default DWARF version"
257 The implicit default version of DWARF debug info produced by a
258 toolchain changes over time.
260 This can break consumers of the debug info that haven't upgraded to
261 support newer revisions, and prevent testing newer versions, but
262 those should be less common scenarios.
264 config DEBUG_INFO_DWARF4
265 bool "Generate DWARF Version 4 debuginfo"
267 depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)))
269 Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2
270 if using clang without clang's integrated assembler, and gdb 7.0+.
272 If you have consumers of DWARF debug info that are not ready for
273 newer revisions of DWARF, you may wish to choose this or have your
276 config DEBUG_INFO_DWARF5
277 bool "Generate DWARF Version 5 debuginfo"
279 depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)))
281 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
282 5.0+ accepts the -gdwarf-5 flag but only had partial support for some
283 draft features until 7.0), and gdb 8.0+.
285 Changes to the structure of debug info in Version 5 allow for around
286 15-18% savings in resulting image and debug info section sizes as
287 compared to DWARF Version 4. DWARF Version 5 standardizes previous
288 extensions such as accelerators for symbol indexing and the format
289 for fission (.dwo/.dwp) files. Users may not want to select this
290 config if they rely on tooling that has not yet been updated to
291 support DWARF Version 5.
293 endchoice # "Debug information"
297 config DEBUG_INFO_REDUCED
298 bool "Reduce debugging information"
300 If you say Y here gcc is instructed to generate less debugging
301 information for structure types. This means that tools that
302 need full debugging information (like kgdb or systemtap) won't
303 be happy. But if you merely need debugging information to
304 resolve line numbers there is no loss. Advantage is that
305 build directory object sizes shrink dramatically over a full
306 DEBUG_INFO build and compile times are reduced too.
307 Only works with newer gcc versions.
309 config DEBUG_INFO_COMPRESSED
310 bool "Compressed debugging information"
311 depends on $(cc-option,-gz=zlib)
312 depends on $(ld-option,--compress-debug-sections=zlib)
314 Compress the debug information using zlib. Requires GCC 5.0+ or Clang
315 5.0+, binutils 2.26+, and zlib.
317 Users of dpkg-deb via scripts/package/builddeb may find an increase in
318 size of their debug .deb packages with this config set, due to the
319 debug info being compressed with zlib, then the object files being
320 recompressed with a different compression scheme. But this is still
321 preferable to setting $KDEB_COMPRESS to "none" which would be even
324 config DEBUG_INFO_SPLIT
325 bool "Produce split debuginfo in .dwo files"
326 depends on $(cc-option,-gsplit-dwarf)
328 Generate debug info into separate .dwo files. This significantly
329 reduces the build directory size for builds with DEBUG_INFO,
330 because it stores the information only once on disk in .dwo
331 files instead of multiple times in object files and executables.
332 In addition the debug information is also compressed.
334 Requires recent gcc (4.7+) and recent gdb/binutils.
335 Any tool that packages or reads debug information would need
336 to know about the .dwo files and include them.
337 Incompatible with older versions of ccache.
339 config DEBUG_INFO_BTF
340 bool "Generate BTF typeinfo"
341 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
342 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
343 depends on BPF_SYSCALL
344 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121
346 Generate deduplicated BTF type information from DWARF debug info.
347 Turning this on expects presence of pahole tool, which will convert
348 DWARF type info into equivalent deduplicated BTF type info.
350 config PAHOLE_HAS_SPLIT_BTF
351 def_bool PAHOLE_VERSION >= 119
353 config PAHOLE_HAS_BTF_TAG
354 def_bool PAHOLE_VERSION >= 123
355 depends on CC_IS_CLANG
357 Decide whether pahole emits btf_tag attributes (btf_type_tag and
358 btf_decl_tag) or not. Currently only clang compiler implements
359 these attributes, so make the config depend on CC_IS_CLANG.
361 config DEBUG_INFO_BTF_MODULES
363 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
365 Generate compact split BTF type information for kernel modules.
367 config MODULE_ALLOW_BTF_MISMATCH
368 bool "Allow loading modules with non-matching BTF type info"
369 depends on DEBUG_INFO_BTF_MODULES
371 For modules whose split BTF does not match vmlinux, load without
372 BTF rather than refusing to load. The default behavior with
373 module BTF enabled is to reject modules with such mismatches;
374 this option will still load module BTF where possible but ignore
375 it when a mismatch is found.
378 bool "Provide GDB scripts for kernel debugging"
380 This creates the required links to GDB helper scripts in the
381 build directory. If you load vmlinux into gdb, the helper
382 scripts will be automatically imported by gdb as well, and
383 additional functions are available to analyze a Linux kernel
384 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
390 int "Warn for stack frames larger than"
392 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
393 default 2048 if PARISC
394 default 1536 if (!64BIT && XTENSA)
395 default 1024 if !64BIT
396 default 2048 if 64BIT
398 Tell gcc to warn at build time for stack frames larger than this.
399 Setting this too low will cause a lot of warnings.
400 Setting it to 0 disables the warning.
402 config STRIP_ASM_SYMS
403 bool "Strip assembler-generated symbols during link"
406 Strip internal assembler-generated symbols during a link (symbols
407 that look like '.Lxxx') so they don't pollute the output of
408 get_wchan() and suchlike.
411 bool "Generate readable assembler code"
412 depends on DEBUG_KERNEL
415 Disable some compiler optimizations that tend to generate human unreadable
416 assembler output. This may make the kernel slightly slower, but it helps
417 to keep kernel developers who have to stare a lot at assembler listings
420 config HEADERS_INSTALL
421 bool "Install uapi headers to usr/include"
424 This option will install uapi headers (headers exported to user-space)
425 into the usr/include directory for use during the kernel build.
426 This is unneeded for building the kernel itself, but needed for some
427 user-space program samples. It is also needed by some features such
428 as uapi header sanity checks.
430 config DEBUG_SECTION_MISMATCH
431 bool "Enable full Section mismatch analysis"
434 The section mismatch analysis checks if there are illegal
435 references from one section to another section.
436 During linktime or runtime, some sections are dropped;
437 any use of code/data previously in these sections would
438 most likely result in an oops.
439 In the code, functions and variables are annotated with
440 __init,, etc. (see the full list in include/linux/init.h),
441 which results in the code/data being placed in specific sections.
442 The section mismatch analysis is always performed after a full
443 kernel build, and enabling this option causes the following
444 additional step to occur:
445 - Add the option -fno-inline-functions-called-once to gcc commands.
446 When inlining a function annotated with __init in a non-init
447 function, we would lose the section information and thus
448 the analysis would not catch the illegal reference.
449 This option tells gcc to inline less (but it does result in
452 config SECTION_MISMATCH_WARN_ONLY
453 bool "Make section mismatch errors non-fatal"
456 If you say N here, the build process will fail if there are any
457 section mismatch, instead of just throwing warnings.
461 config DEBUG_FORCE_FUNCTION_ALIGN_64B
462 bool "Force all function address 64B aligned"
463 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC)
465 There are cases that a commit from one domain changes the function
466 address alignment of other domains, and cause magic performance
467 bump (regression or improvement). Enable this option will help to
468 verify if the bump is caused by function alignment changes, while
469 it will slightly increase the kernel size and affect icache usage.
471 It is mainly for debug and performance tuning use.
474 # Select this config option from the architecture Kconfig, if it
475 # is preferred to always offer frame pointers as a config
476 # option on the architecture (regardless of KERNEL_DEBUG):
478 config ARCH_WANT_FRAME_POINTERS
482 bool "Compile the kernel with frame pointers"
483 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
484 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
486 If you say Y here the resulting kernel image will be slightly
487 larger and slower, but it gives very useful debugging information
488 in case of kernel bugs. (precise oopses/stacktraces/warnings)
493 config STACK_VALIDATION
494 bool "Compile-time stack metadata validation"
495 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
499 Validate frame pointer rules at compile-time. This helps ensure that
500 runtime stack traces are more reliable.
502 For more information, see
503 tools/objtool/Documentation/stack-validation.txt.
505 config NOINSTR_VALIDATION
507 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
512 bool "Generate vmlinux.map file when linking"
515 Selecting this option will pass "-Map=vmlinux.map" to ld
516 when linking vmlinux. That file can be useful for verifying
517 and debugging magic section games, and for seeing which
518 pieces of code get eliminated with
519 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
521 config DEBUG_FORCE_WEAK_PER_CPU
522 bool "Force weak per-cpu definitions"
523 depends on DEBUG_KERNEL
525 s390 and alpha require percpu variables in modules to be
526 defined weak to work around addressing range issue which
527 puts the following two restrictions on percpu variable
530 1. percpu symbols must be unique whether static or not
531 2. percpu variables can't be defined inside a function
533 To ensure that generic code follows the above rules, this
534 option forces all percpu variables to be defined as weak.
536 endmenu # "Compiler options"
538 menu "Generic Kernel Debugging Instruments"
541 bool "Magic SysRq key"
544 If you say Y here, you will have some control over the system even
545 if the system crashes for example during kernel debugging (e.g., you
546 will be able to flush the buffer cache to disk, reboot the system
547 immediately or dump some status information). This is accomplished
548 by pressing various keys while holding SysRq (Alt+PrintScreen). It
549 also works on a serial console (on PC hardware at least), if you
550 send a BREAK and then within 5 seconds a command keypress. The
551 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
552 Don't say Y unless you really know what this hack does.
554 config MAGIC_SYSRQ_DEFAULT_ENABLE
555 hex "Enable magic SysRq key functions by default"
556 depends on MAGIC_SYSRQ
559 Specifies which SysRq key functions are enabled by default.
560 This may be set to 1 or 0 to enable or disable them all, or
561 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
563 config MAGIC_SYSRQ_SERIAL
564 bool "Enable magic SysRq key over serial"
565 depends on MAGIC_SYSRQ
568 Many embedded boards have a disconnected TTL level serial which can
569 generate some garbage that can lead to spurious false sysrq detects.
570 This option allows you to decide whether you want to enable the
573 config MAGIC_SYSRQ_SERIAL_SEQUENCE
574 string "Char sequence that enables magic SysRq over serial"
575 depends on MAGIC_SYSRQ_SERIAL
578 Specifies a sequence of characters that can follow BREAK to enable
579 SysRq on a serial console.
581 If unsure, leave an empty string and the option will not be enabled.
584 bool "Debug Filesystem"
586 debugfs is a virtual file system that kernel developers use to put
587 debugging files into. Enable this option to be able to read and
588 write to these files.
590 For detailed documentation on the debugfs API, see
591 Documentation/filesystems/.
596 prompt "Debugfs default access"
598 default DEBUG_FS_ALLOW_ALL
600 This selects the default access restrictions for debugfs.
601 It can be overridden with kernel command line option
602 debugfs=[on,no-mount,off]. The restrictions apply for API access
603 and filesystem registration.
605 config DEBUG_FS_ALLOW_ALL
608 No restrictions apply. Both API and filesystem registration
609 is on. This is the normal default operation.
611 config DEBUG_FS_DISALLOW_MOUNT
612 bool "Do not register debugfs as filesystem"
614 The API is open but filesystem is not loaded. Clients can still do
615 their work and read with debug tools that do not need
618 config DEBUG_FS_ALLOW_NONE
621 Access is off. Clients get -PERM when trying to create nodes in
622 debugfs tree and debugfs is not registered as a filesystem.
623 Client can then back-off or continue without debugfs access.
627 source "lib/Kconfig.kgdb"
628 source "lib/Kconfig.ubsan"
629 source "lib/Kconfig.kcsan"
633 menu "Networking Debugging"
635 source "net/Kconfig.debug"
637 endmenu # "Networking Debugging"
639 menu "Memory Debugging"
641 source "mm/Kconfig.debug"
644 bool "Debug object operations"
645 depends on DEBUG_KERNEL
647 If you say Y here, additional code will be inserted into the
648 kernel to track the life time of various objects and validate
649 the operations on those objects.
651 config DEBUG_OBJECTS_SELFTEST
652 bool "Debug objects selftest"
653 depends on DEBUG_OBJECTS
655 This enables the selftest of the object debug code.
657 config DEBUG_OBJECTS_FREE
658 bool "Debug objects in freed memory"
659 depends on DEBUG_OBJECTS
661 This enables checks whether a k/v free operation frees an area
662 which contains an object which has not been deactivated
663 properly. This can make kmalloc/kfree-intensive workloads
666 config DEBUG_OBJECTS_TIMERS
667 bool "Debug timer objects"
668 depends on DEBUG_OBJECTS
670 If you say Y here, additional code will be inserted into the
671 timer routines to track the life time of timer objects and
672 validate the timer operations.
674 config DEBUG_OBJECTS_WORK
675 bool "Debug work objects"
676 depends on DEBUG_OBJECTS
678 If you say Y here, additional code will be inserted into the
679 work queue routines to track the life time of work objects and
680 validate the work operations.
682 config DEBUG_OBJECTS_RCU_HEAD
683 bool "Debug RCU callbacks objects"
684 depends on DEBUG_OBJECTS
686 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
688 config DEBUG_OBJECTS_PERCPU_COUNTER
689 bool "Debug percpu counter objects"
690 depends on DEBUG_OBJECTS
692 If you say Y here, additional code will be inserted into the
693 percpu counter routines to track the life time of percpu counter
694 objects and validate the percpu counter operations.
696 config DEBUG_OBJECTS_ENABLE_DEFAULT
697 int "debug_objects bootup default value (0-1)"
700 depends on DEBUG_OBJECTS
702 Debug objects boot parameter default value
704 config HAVE_DEBUG_KMEMLEAK
707 config DEBUG_KMEMLEAK
708 bool "Kernel memory leak detector"
709 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
711 select STACKTRACE if STACKTRACE_SUPPORT
715 Say Y here if you want to enable the memory leak
716 detector. The memory allocation/freeing is traced in a way
717 similar to the Boehm's conservative garbage collector, the
718 difference being that the orphan objects are not freed but
719 only shown in /sys/kernel/debug/kmemleak. Enabling this
720 feature will introduce an overhead to memory
721 allocations. See Documentation/dev-tools/kmemleak.rst for more
724 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
725 of finding leaks due to the slab objects poisoning.
727 In order to access the kmemleak file, debugfs needs to be
728 mounted (usually at /sys/kernel/debug).
730 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
731 int "Kmemleak memory pool size"
732 depends on DEBUG_KMEMLEAK
736 Kmemleak must track all the memory allocations to avoid
737 reporting false positives. Since memory may be allocated or
738 freed before kmemleak is fully initialised, use a static pool
739 of metadata objects to track such callbacks. After kmemleak is
740 fully initialised, this memory pool acts as an emergency one
741 if slab allocations fail.
743 config DEBUG_KMEMLEAK_TEST
744 tristate "Simple test for the kernel memory leak detector"
745 depends on DEBUG_KMEMLEAK && m
747 This option enables a module that explicitly leaks memory.
751 config DEBUG_KMEMLEAK_DEFAULT_OFF
752 bool "Default kmemleak to off"
753 depends on DEBUG_KMEMLEAK
755 Say Y here to disable kmemleak by default. It can then be enabled
756 on the command line via kmemleak=on.
758 config DEBUG_KMEMLEAK_AUTO_SCAN
759 bool "Enable kmemleak auto scan thread on boot up"
761 depends on DEBUG_KMEMLEAK
763 Depending on the cpu, kmemleak scan may be cpu intensive and can
764 stall user tasks at times. This option enables/disables automatic
765 kmemleak scan at boot up.
767 Say N here to disable kmemleak auto scan thread to stop automatic
768 scanning. Disabling this option disables automatic reporting of
773 config DEBUG_STACK_USAGE
774 bool "Stack utilization instrumentation"
775 depends on DEBUG_KERNEL && !IA64
777 Enables the display of the minimum amount of free stack which each
778 task has ever had available in the sysrq-T and sysrq-P debug output.
780 This option will slow down process creation somewhat.
782 config SCHED_STACK_END_CHECK
783 bool "Detect stack corruption on calls to schedule()"
784 depends on DEBUG_KERNEL
787 This option checks for a stack overrun on calls to schedule().
788 If the stack end location is found to be over written always panic as
789 the content of the corrupted region can no longer be trusted.
790 This is to ensure no erroneous behaviour occurs which could result in
791 data corruption or a sporadic crash at a later stage once the region
792 is examined. The runtime overhead introduced is minimal.
794 config ARCH_HAS_DEBUG_VM_PGTABLE
797 An architecture should select this when it can successfully
798 build and run DEBUG_VM_PGTABLE.
802 depends on DEBUG_KERNEL
804 Enable this to turn on extended checks in the virtual-memory system
805 that may impact performance.
809 config DEBUG_VM_VMACACHE
810 bool "Debug VMA caching"
813 Enable this to turn on VMA caching debug information. Doing so
814 can cause significant overhead, so only enable it in non-production
820 bool "Debug VM red-black trees"
823 Enable VM red-black tree debugging information and extra validations.
827 config DEBUG_VM_PGFLAGS
828 bool "Debug page-flags operations"
831 Enables extra validation on page flags operations.
835 config DEBUG_VM_PGTABLE
836 bool "Debug arch page table for semantics compliance"
838 depends on ARCH_HAS_DEBUG_VM_PGTABLE
839 default y if DEBUG_VM
841 This option provides a debug method which can be used to test
842 architecture page table helper functions on various platforms in
843 verifying if they comply with expected generic MM semantics. This
844 will help architecture code in making sure that any changes or
845 new additions of these helpers still conform to expected
846 semantics of the generic MM. Platforms will have to opt in for
847 this through ARCH_HAS_DEBUG_VM_PGTABLE.
851 config ARCH_HAS_DEBUG_VIRTUAL
855 bool "Debug VM translations"
856 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
858 Enable some costly sanity checks in virtual to page code. This can
859 catch mistakes with virt_to_page() and friends.
863 config DEBUG_NOMMU_REGIONS
864 bool "Debug the global anon/private NOMMU mapping region tree"
865 depends on DEBUG_KERNEL && !MMU
867 This option causes the global tree of anonymous and private mapping
868 regions to be regularly checked for invalid topology.
870 config DEBUG_MEMORY_INIT
871 bool "Debug memory initialisation" if EXPERT
874 Enable this for additional checks during memory initialisation.
875 The sanity checks verify aspects of the VM such as the memory model
876 and other information provided by the architecture. Verbose
877 information will be printed at KERN_DEBUG loglevel depending
878 on the mminit_loglevel= command-line option.
882 config MEMORY_NOTIFIER_ERROR_INJECT
883 tristate "Memory hotplug notifier error injection module"
884 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
886 This option provides the ability to inject artificial errors to
887 memory hotplug notifier chain callbacks. It is controlled through
888 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
890 If the notifier call chain should be failed with some events
891 notified, write the error code to "actions/<notifier event>/error".
893 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
895 # cd /sys/kernel/debug/notifier-error-inject/memory
896 # echo -12 > actions/MEM_GOING_OFFLINE/error
897 # echo offline > /sys/devices/system/memory/memoryXXX/state
898 bash: echo: write error: Cannot allocate memory
900 To compile this code as a module, choose M here: the module will
901 be called memory-notifier-error-inject.
905 config DEBUG_PER_CPU_MAPS
906 bool "Debug access to per_cpu maps"
907 depends on DEBUG_KERNEL
910 Say Y to verify that the per_cpu map being accessed has
911 been set up. This adds a fair amount of code to kernel memory
912 and decreases performance.
916 config DEBUG_KMAP_LOCAL
917 bool "Debug kmap_local temporary mappings"
918 depends on DEBUG_KERNEL && KMAP_LOCAL
920 This option enables additional error checking for the kmap_local
921 infrastructure. Disable for production use.
923 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
926 config DEBUG_KMAP_LOCAL_FORCE_MAP
927 bool "Enforce kmap_local temporary mappings"
928 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
930 select DEBUG_KMAP_LOCAL
932 This option enforces temporary mappings through the kmap_local
933 mechanism for non-highmem pages and on non-highmem systems.
934 Disable this for production systems!
937 bool "Highmem debugging"
938 depends on DEBUG_KERNEL && HIGHMEM
939 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
940 select DEBUG_KMAP_LOCAL
942 This option enables additional error checking for high memory
943 systems. Disable for production systems.
945 config HAVE_DEBUG_STACKOVERFLOW
948 config DEBUG_STACKOVERFLOW
949 bool "Check for stack overflows"
950 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
952 Say Y here if you want to check for overflows of kernel, IRQ
953 and exception stacks (if your architecture uses them). This
954 option will show detailed messages if free stack space drops
955 below a certain limit.
957 These kinds of bugs usually occur when call-chains in the
958 kernel get too deep, especially when interrupts are
961 Use this in cases where you see apparently random memory
962 corruption, especially if it appears in 'struct thread_info'
964 If in doubt, say "N".
966 source "lib/Kconfig.kasan"
967 source "lib/Kconfig.kfence"
969 endmenu # "Memory Debugging"
972 bool "Debug shared IRQ handlers"
973 depends on DEBUG_KERNEL
975 Enable this to generate a spurious interrupt just before a shared
976 interrupt handler is deregistered (generating one when registering
977 is currently disabled). Drivers need to handle this correctly. Some
978 don't and need to be caught.
980 menu "Debug Oops, Lockups and Hangs"
985 Say Y here to enable the kernel to panic when it oopses. This
986 has the same effect as setting oops=panic on the kernel command
989 This feature is useful to ensure that the kernel does not do
990 anything erroneous after an oops which could result in data
991 corruption or other issues.
995 config PANIC_ON_OOPS_VALUE
998 default 0 if !PANIC_ON_OOPS
999 default 1 if PANIC_ON_OOPS
1001 config PANIC_TIMEOUT
1005 Set the timeout value (in seconds) until a reboot occurs when
1006 the kernel panics. If n = 0, then we wait forever. A timeout
1007 value n > 0 will wait n seconds before rebooting, while a timeout
1008 value n < 0 will reboot immediately.
1010 config LOCKUP_DETECTOR
1013 config SOFTLOCKUP_DETECTOR
1014 bool "Detect Soft Lockups"
1015 depends on DEBUG_KERNEL && !S390
1016 select LOCKUP_DETECTOR
1018 Say Y here to enable the kernel to act as a watchdog to detect
1021 Softlockups are bugs that cause the kernel to loop in kernel
1022 mode for more than 20 seconds, without giving other tasks a
1023 chance to run. The current stack trace is displayed upon
1024 detection and the system will stay locked up.
1026 config BOOTPARAM_SOFTLOCKUP_PANIC
1027 bool "Panic (Reboot) On Soft Lockups"
1028 depends on SOFTLOCKUP_DETECTOR
1030 Say Y here to enable the kernel to panic on "soft lockups",
1031 which are bugs that cause the kernel to loop in kernel
1032 mode for more than 20 seconds (configurable using the watchdog_thresh
1033 sysctl), without giving other tasks a chance to run.
1035 The panic can be used in combination with panic_timeout,
1036 to cause the system to reboot automatically after a
1037 lockup has been detected. This feature is useful for
1038 high-availability systems that have uptime guarantees and
1039 where a lockup must be resolved ASAP.
1043 config HARDLOCKUP_DETECTOR_PERF
1045 select SOFTLOCKUP_DETECTOR
1048 # Enables a timestamp based low pass filter to compensate for perf based
1049 # hard lockup detection which runs too fast due to turbo modes.
1051 config HARDLOCKUP_CHECK_TIMESTAMP
1055 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1056 # lockup detector rather than the perf based detector.
1058 config HARDLOCKUP_DETECTOR
1059 bool "Detect Hard Lockups"
1060 depends on DEBUG_KERNEL && !S390
1061 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1062 select LOCKUP_DETECTOR
1063 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1065 Say Y here to enable the kernel to act as a watchdog to detect
1068 Hardlockups are bugs that cause the CPU to loop in kernel mode
1069 for more than 10 seconds, without letting other interrupts have a
1070 chance to run. The current stack trace is displayed upon detection
1071 and the system will stay locked up.
1073 config BOOTPARAM_HARDLOCKUP_PANIC
1074 bool "Panic (Reboot) On Hard Lockups"
1075 depends on HARDLOCKUP_DETECTOR
1077 Say Y here to enable the kernel to panic on "hard lockups",
1078 which are bugs that cause the kernel to loop in kernel
1079 mode with interrupts disabled for more than 10 seconds (configurable
1080 using the watchdog_thresh sysctl).
1084 config DETECT_HUNG_TASK
1085 bool "Detect Hung Tasks"
1086 depends on DEBUG_KERNEL
1087 default SOFTLOCKUP_DETECTOR
1089 Say Y here to enable the kernel to detect "hung tasks",
1090 which are bugs that cause the task to be stuck in
1091 uninterruptible "D" state indefinitely.
1093 When a hung task is detected, the kernel will print the
1094 current stack trace (which you should report), but the
1095 task will stay in uninterruptible state. If lockdep is
1096 enabled then all held locks will also be reported. This
1097 feature has negligible overhead.
1099 config DEFAULT_HUNG_TASK_TIMEOUT
1100 int "Default timeout for hung task detection (in seconds)"
1101 depends on DETECT_HUNG_TASK
1104 This option controls the default timeout (in seconds) used
1105 to determine when a task has become non-responsive and should
1108 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1109 sysctl or by writing a value to
1110 /proc/sys/kernel/hung_task_timeout_secs.
1112 A timeout of 0 disables the check. The default is two minutes.
1113 Keeping the default should be fine in most cases.
1115 config BOOTPARAM_HUNG_TASK_PANIC
1116 bool "Panic (Reboot) On Hung Tasks"
1117 depends on DETECT_HUNG_TASK
1119 Say Y here to enable the kernel to panic on "hung tasks",
1120 which are bugs that cause the kernel to leave a task stuck
1121 in uninterruptible "D" state.
1123 The panic can be used in combination with panic_timeout,
1124 to cause the system to reboot automatically after a
1125 hung task has been detected. This feature is useful for
1126 high-availability systems that have uptime guarantees and
1127 where a hung tasks must be resolved ASAP.
1132 bool "Detect Workqueue Stalls"
1133 depends on DEBUG_KERNEL
1135 Say Y here to enable stall detection on workqueues. If a
1136 worker pool doesn't make forward progress on a pending work
1137 item for over a given amount of time, 30s by default, a
1138 warning message is printed along with dump of workqueue
1139 state. This can be configured through kernel parameter
1140 "workqueue.watchdog_thresh" and its sysfs counterpart.
1143 tristate "Test module to generate lockups"
1146 This builds the "test_lockup" module that helps to make sure
1147 that watchdogs and lockup detectors are working properly.
1149 Depending on module parameters it could emulate soft or hard
1150 lockup, "hung task", or locking arbitrary lock for a long time.
1151 Also it could generate series of lockups with cooling-down periods.
1155 endmenu # "Debug lockups and hangs"
1157 menu "Scheduler Debugging"
1160 bool "Collect scheduler debugging info"
1161 depends on DEBUG_KERNEL && PROC_FS
1164 If you say Y here, the /proc/sched_debug file will be provided
1165 that can help debug the scheduler. The runtime overhead of this
1173 bool "Collect scheduler statistics"
1174 depends on DEBUG_KERNEL && PROC_FS
1177 If you say Y here, additional code will be inserted into the
1178 scheduler and related routines to collect statistics about
1179 scheduler behavior and provide them in /proc/schedstat. These
1180 stats may be useful for both tuning and debugging the scheduler
1181 If you aren't debugging the scheduler or trying to tune a specific
1182 application, you can say N to avoid the very slight overhead
1187 config DEBUG_TIMEKEEPING
1188 bool "Enable extra timekeeping sanity checking"
1190 This option will enable additional timekeeping sanity checks
1191 which may be helpful when diagnosing issues where timekeeping
1192 problems are suspected.
1194 This may include checks in the timekeeping hotpaths, so this
1195 option may have a (very small) performance impact to some
1200 config DEBUG_PREEMPT
1201 bool "Debug preemptible kernel"
1202 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1205 If you say Y here then the kernel will use a debug variant of the
1206 commonly used smp_processor_id() function and will print warnings
1207 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1208 will detect preemption count underflows.
1210 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1212 config LOCK_DEBUGGING_SUPPORT
1214 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1217 config PROVE_LOCKING
1218 bool "Lock debugging: prove locking correctness"
1219 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1221 select DEBUG_SPINLOCK
1222 select DEBUG_MUTEXES if !PREEMPT_RT
1223 select DEBUG_RT_MUTEXES if RT_MUTEXES
1225 select DEBUG_WW_MUTEX_SLOWPATH
1226 select DEBUG_LOCK_ALLOC
1227 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1228 select TRACE_IRQFLAGS
1231 This feature enables the kernel to prove that all locking
1232 that occurs in the kernel runtime is mathematically
1233 correct: that under no circumstance could an arbitrary (and
1234 not yet triggered) combination of observed locking
1235 sequences (on an arbitrary number of CPUs, running an
1236 arbitrary number of tasks and interrupt contexts) cause a
1239 In short, this feature enables the kernel to report locking
1240 related deadlocks before they actually occur.
1242 The proof does not depend on how hard and complex a
1243 deadlock scenario would be to trigger: how many
1244 participant CPUs, tasks and irq-contexts would be needed
1245 for it to trigger. The proof also does not depend on
1246 timing: if a race and a resulting deadlock is possible
1247 theoretically (no matter how unlikely the race scenario
1248 is), it will be proven so and will immediately be
1249 reported by the kernel (once the event is observed that
1250 makes the deadlock theoretically possible).
1252 If a deadlock is impossible (i.e. the locking rules, as
1253 observed by the kernel, are mathematically correct), the
1254 kernel reports nothing.
1256 NOTE: this feature can also be enabled for rwlocks, mutexes
1257 and rwsems - in which case all dependencies between these
1258 different locking variants are observed and mapped too, and
1259 the proof of observed correctness is also maintained for an
1260 arbitrary combination of these separate locking variants.
1262 For more details, see Documentation/locking/lockdep-design.rst.
1264 config PROVE_RAW_LOCK_NESTING
1265 bool "Enable raw_spinlock - spinlock nesting checks"
1266 depends on PROVE_LOCKING
1269 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1270 that the lock nesting rules for PREEMPT_RT enabled kernels are
1273 NOTE: There are known nesting problems. So if you enable this
1274 option expect lockdep splats until these problems have been fully
1275 addressed which is work in progress. This config switch allows to
1276 identify and analyze these problems. It will be removed and the
1277 check permanently enabled once the main issues have been fixed.
1279 If unsure, select N.
1282 bool "Lock usage statistics"
1283 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1285 select DEBUG_SPINLOCK
1286 select DEBUG_MUTEXES if !PREEMPT_RT
1287 select DEBUG_RT_MUTEXES if RT_MUTEXES
1288 select DEBUG_LOCK_ALLOC
1291 This feature enables tracking lock contention points
1293 For more details, see Documentation/locking/lockstat.rst
1295 This also enables lock events required by "perf lock",
1297 If you want to use "perf lock", you also need to turn on
1298 CONFIG_EVENT_TRACING.
1300 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1301 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1303 config DEBUG_RT_MUTEXES
1304 bool "RT Mutex debugging, deadlock detection"
1305 depends on DEBUG_KERNEL && RT_MUTEXES
1307 This allows rt mutex semantics violations and rt mutex related
1308 deadlocks (lockups) to be detected and reported automatically.
1310 config DEBUG_SPINLOCK
1311 bool "Spinlock and rw-lock debugging: basic checks"
1312 depends on DEBUG_KERNEL
1313 select UNINLINE_SPIN_UNLOCK
1315 Say Y here and build SMP to catch missing spinlock initialization
1316 and certain other kinds of spinlock errors commonly made. This is
1317 best used in conjunction with the NMI watchdog so that spinlock
1318 deadlocks are also debuggable.
1320 config DEBUG_MUTEXES
1321 bool "Mutex debugging: basic checks"
1322 depends on DEBUG_KERNEL && !PREEMPT_RT
1324 This feature allows mutex semantics violations to be detected and
1327 config DEBUG_WW_MUTEX_SLOWPATH
1328 bool "Wait/wound mutex debugging: Slowpath testing"
1329 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1330 select DEBUG_LOCK_ALLOC
1331 select DEBUG_SPINLOCK
1332 select DEBUG_MUTEXES if !PREEMPT_RT
1333 select DEBUG_RT_MUTEXES if PREEMPT_RT
1335 This feature enables slowpath testing for w/w mutex users by
1336 injecting additional -EDEADLK wound/backoff cases. Together with
1337 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1338 will test all possible w/w mutex interface abuse with the
1339 exception of simply not acquiring all the required locks.
1340 Note that this feature can introduce significant overhead, so
1341 it really should not be enabled in a production or distro kernel,
1342 even a debug kernel. If you are a driver writer, enable it. If
1343 you are a distro, do not.
1346 bool "RW Semaphore debugging: basic checks"
1347 depends on DEBUG_KERNEL
1349 This debugging feature allows mismatched rw semaphore locks
1350 and unlocks to be detected and reported.
1352 config DEBUG_LOCK_ALLOC
1353 bool "Lock debugging: detect incorrect freeing of live locks"
1354 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1355 select DEBUG_SPINLOCK
1356 select DEBUG_MUTEXES if !PREEMPT_RT
1357 select DEBUG_RT_MUTEXES if RT_MUTEXES
1360 This feature will check whether any held lock (spinlock, rwlock,
1361 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1362 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1363 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1364 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1365 held during task exit.
1369 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1374 config LOCKDEP_SMALL
1378 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1379 depends on LOCKDEP && !LOCKDEP_SMALL
1383 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1385 config LOCKDEP_CHAINS_BITS
1386 int "Bitsize for MAX_LOCKDEP_CHAINS"
1387 depends on LOCKDEP && !LOCKDEP_SMALL
1391 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1393 config LOCKDEP_STACK_TRACE_BITS
1394 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1395 depends on LOCKDEP && !LOCKDEP_SMALL
1399 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1401 config LOCKDEP_STACK_TRACE_HASH_BITS
1402 int "Bitsize for STACK_TRACE_HASH_SIZE"
1403 depends on LOCKDEP && !LOCKDEP_SMALL
1407 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1409 config LOCKDEP_CIRCULAR_QUEUE_BITS
1410 int "Bitsize for elements in circular_queue struct"
1415 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1417 config DEBUG_LOCKDEP
1418 bool "Lock dependency engine debugging"
1419 depends on DEBUG_KERNEL && LOCKDEP
1420 select DEBUG_IRQFLAGS
1422 If you say Y here, the lock dependency engine will do
1423 additional runtime checks to debug itself, at the price
1424 of more runtime overhead.
1426 config DEBUG_ATOMIC_SLEEP
1427 bool "Sleep inside atomic section checking"
1428 select PREEMPT_COUNT
1429 depends on DEBUG_KERNEL
1430 depends on !ARCH_NO_PREEMPT
1432 If you say Y here, various routines which may sleep will become very
1433 noisy if they are called inside atomic sections: when a spinlock is
1434 held, inside an rcu read side critical section, inside preempt disabled
1435 sections, inside an interrupt, etc...
1437 config DEBUG_LOCKING_API_SELFTESTS
1438 bool "Locking API boot-time self-tests"
1439 depends on DEBUG_KERNEL
1441 Say Y here if you want the kernel to run a short self-test during
1442 bootup. The self-test checks whether common types of locking bugs
1443 are detected by debugging mechanisms or not. (if you disable
1444 lock debugging then those bugs won't be detected of course.)
1445 The following locking APIs are covered: spinlocks, rwlocks,
1448 config LOCK_TORTURE_TEST
1449 tristate "torture tests for locking"
1450 depends on DEBUG_KERNEL
1453 This option provides a kernel module that runs torture tests
1454 on kernel locking primitives. The kernel module may be built
1455 after the fact on the running kernel to be tested, if desired.
1457 Say Y here if you want kernel locking-primitive torture tests
1458 to be built into the kernel.
1459 Say M if you want these torture tests to build as a module.
1460 Say N if you are unsure.
1462 config WW_MUTEX_SELFTEST
1463 tristate "Wait/wound mutex selftests"
1465 This option provides a kernel module that runs tests on the
1466 on the struct ww_mutex locking API.
1468 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1469 with this test harness.
1471 Say M if you want these self tests to build as a module.
1472 Say N if you are unsure.
1474 config SCF_TORTURE_TEST
1475 tristate "torture tests for smp_call_function*()"
1476 depends on DEBUG_KERNEL
1479 This option provides a kernel module that runs torture tests
1480 on the smp_call_function() family of primitives. The kernel
1481 module may be built after the fact on the running kernel to
1482 be tested, if desired.
1484 config CSD_LOCK_WAIT_DEBUG
1485 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1486 depends on DEBUG_KERNEL
1490 This option enables debug prints when CPUs are slow to respond
1491 to the smp_call_function*() IPI wrappers. These debug prints
1492 include the IPI handler function currently executing (if any)
1493 and relevant stack traces.
1495 endmenu # lock debugging
1497 config TRACE_IRQFLAGS
1498 depends on TRACE_IRQFLAGS_SUPPORT
1501 Enables hooks to interrupt enabling and disabling for
1502 either tracing or lock debugging.
1504 config TRACE_IRQFLAGS_NMI
1506 depends on TRACE_IRQFLAGS
1507 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1509 config DEBUG_IRQFLAGS
1510 bool "Debug IRQ flag manipulation"
1512 Enables checks for potentially unsafe enabling or disabling of
1513 interrupts, such as calling raw_local_irq_restore() when interrupts
1517 bool "Stack backtrace support"
1518 depends on STACKTRACE_SUPPORT
1520 This option causes the kernel to create a /proc/pid/stack for
1521 every process, showing its current stack trace.
1522 It is also used by various kernel debugging features that require
1523 stack trace generation.
1525 config WARN_ALL_UNSEEDED_RANDOM
1526 bool "Warn for all uses of unseeded randomness"
1529 Some parts of the kernel contain bugs relating to their use of
1530 cryptographically secure random numbers before it's actually possible
1531 to generate those numbers securely. This setting ensures that these
1532 flaws don't go unnoticed, by enabling a message, should this ever
1533 occur. This will allow people with obscure setups to know when things
1534 are going wrong, so that they might contact developers about fixing
1537 Unfortunately, on some models of some architectures getting
1538 a fully seeded CRNG is extremely difficult, and so this can
1539 result in dmesg getting spammed for a surprisingly long
1540 time. This is really bad from a security perspective, and
1541 so architecture maintainers really need to do what they can
1542 to get the CRNG seeded sooner after the system is booted.
1543 However, since users cannot do anything actionable to
1544 address this, by default this option is disabled.
1546 Say Y here if you want to receive warnings for all uses of
1547 unseeded randomness. This will be of use primarily for
1548 those developers interested in improving the security of
1549 Linux kernels running on their architecture (or
1552 config DEBUG_KOBJECT
1553 bool "kobject debugging"
1554 depends on DEBUG_KERNEL
1556 If you say Y here, some extra kobject debugging messages will be sent
1559 config DEBUG_KOBJECT_RELEASE
1560 bool "kobject release debugging"
1561 depends on DEBUG_OBJECTS_TIMERS
1563 kobjects are reference counted objects. This means that their
1564 last reference count put is not predictable, and the kobject can
1565 live on past the point at which a driver decides to drop it's
1566 initial reference to the kobject gained on allocation. An
1567 example of this would be a struct device which has just been
1570 However, some buggy drivers assume that after such an operation,
1571 the memory backing the kobject can be immediately freed. This
1572 goes completely against the principles of a refcounted object.
1574 If you say Y here, the kernel will delay the release of kobjects
1575 on the last reference count to improve the visibility of this
1576 kind of kobject release bug.
1578 config HAVE_DEBUG_BUGVERBOSE
1581 menu "Debug kernel data structures"
1584 bool "Debug linked list manipulation"
1585 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1587 Enable this to turn on extended checks in the linked-list
1593 bool "Debug priority linked list manipulation"
1594 depends on DEBUG_KERNEL
1596 Enable this to turn on extended checks in the priority-ordered
1597 linked-list (plist) walking routines. This checks the entire
1598 list multiple times during each manipulation.
1603 bool "Debug SG table operations"
1604 depends on DEBUG_KERNEL
1606 Enable this to turn on checks on scatter-gather tables. This can
1607 help find problems with drivers that do not properly initialize
1612 config DEBUG_NOTIFIERS
1613 bool "Debug notifier call chains"
1614 depends on DEBUG_KERNEL
1616 Enable this to turn on sanity checking for notifier call chains.
1617 This is most useful for kernel developers to make sure that
1618 modules properly unregister themselves from notifier chains.
1619 This is a relatively cheap check but if you care about maximum
1622 config BUG_ON_DATA_CORRUPTION
1623 bool "Trigger a BUG when data corruption is detected"
1626 Select this option if the kernel should BUG when it encounters
1627 data corruption in kernel memory structures when they get checked
1634 config DEBUG_CREDENTIALS
1635 bool "Debug credential management"
1636 depends on DEBUG_KERNEL
1638 Enable this to turn on some debug checking for credential
1639 management. The additional code keeps track of the number of
1640 pointers from task_structs to any given cred struct, and checks to
1641 see that this number never exceeds the usage count of the cred
1644 Furthermore, if SELinux is enabled, this also checks that the
1645 security pointer in the cred struct is never seen to be invalid.
1649 source "kernel/rcu/Kconfig.debug"
1651 config DEBUG_WQ_FORCE_RR_CPU
1652 bool "Force round-robin CPU selection for unbound work items"
1653 depends on DEBUG_KERNEL
1656 Workqueue used to implicitly guarantee that work items queued
1657 without explicit CPU specified are put on the local CPU. This
1658 guarantee is no longer true and while local CPU is still
1659 preferred work items may be put on foreign CPUs. Kernel
1660 parameter "workqueue.debug_force_rr_cpu" is added to force
1661 round-robin CPU selection to flush out usages which depend on the
1662 now broken guarantee. This config option enables the debug
1663 feature by default. When enabled, memory and cache locality will
1666 config CPU_HOTPLUG_STATE_CONTROL
1667 bool "Enable CPU hotplug state control"
1668 depends on DEBUG_KERNEL
1669 depends on HOTPLUG_CPU
1672 Allows to write steps between "offline" and "online" to the CPUs
1673 sysfs target file so states can be stepped granular. This is a debug
1674 option for now as the hotplug machinery cannot be stopped and
1675 restarted at arbitrary points yet.
1677 Say N if your are unsure.
1680 bool "Latency measuring infrastructure"
1681 depends on DEBUG_KERNEL
1682 depends on STACKTRACE_SUPPORT
1684 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1690 Enable this option if you want to use the LatencyTOP tool
1691 to find out which userspace is blocking on what kernel operations.
1693 source "kernel/trace/Kconfig"
1695 config PROVIDE_OHCI1394_DMA_INIT
1696 bool "Remote debugging over FireWire early on boot"
1697 depends on PCI && X86
1699 If you want to debug problems which hang or crash the kernel early
1700 on boot and the crashing machine has a FireWire port, you can use
1701 this feature to remotely access the memory of the crashed machine
1702 over FireWire. This employs remote DMA as part of the OHCI1394
1703 specification which is now the standard for FireWire controllers.
1705 With remote DMA, you can monitor the printk buffer remotely using
1706 firescope and access all memory below 4GB using fireproxy from gdb.
1707 Even controlling a kernel debugger is possible using remote DMA.
1711 If ohci1394_dma=early is used as boot parameter, it will initialize
1712 all OHCI1394 controllers which are found in the PCI config space.
1714 As all changes to the FireWire bus such as enabling and disabling
1715 devices cause a bus reset and thereby disable remote DMA for all
1716 devices, be sure to have the cable plugged and FireWire enabled on
1717 the debugging host before booting the debug target for debugging.
1719 This code (~1k) is freed after boot. By then, the firewire stack
1720 in charge of the OHCI-1394 controllers should be used instead.
1722 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1724 source "samples/Kconfig"
1726 config ARCH_HAS_DEVMEM_IS_ALLOWED
1729 config STRICT_DEVMEM
1730 bool "Filter access to /dev/mem"
1731 depends on MMU && DEVMEM
1732 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1733 default y if PPC || X86 || ARM64
1735 If this option is disabled, you allow userspace (root) access to all
1736 of memory, including kernel and userspace memory. Accidental
1737 access to this is obviously disastrous, but specific access can
1738 be used by people debugging the kernel. Note that with PAT support
1739 enabled, even in this case there are restrictions on /dev/mem
1740 use due to the cache aliasing requirements.
1742 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1743 file only allows userspace access to PCI space and the BIOS code and
1744 data regions. This is sufficient for dosemu and X and all common
1749 config IO_STRICT_DEVMEM
1750 bool "Filter I/O access to /dev/mem"
1751 depends on STRICT_DEVMEM
1753 If this option is disabled, you allow userspace (root) access to all
1754 io-memory regardless of whether a driver is actively using that
1755 range. Accidental access to this is obviously disastrous, but
1756 specific access can be used by people debugging kernel drivers.
1758 If this option is switched on, the /dev/mem file only allows
1759 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1760 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1761 if the driver using a given range cannot be disabled.
1765 menu "$(SRCARCH) Debugging"
1767 source "arch/$(SRCARCH)/Kconfig.debug"
1771 menu "Kernel Testing and Coverage"
1773 source "lib/kunit/Kconfig"
1775 config NOTIFIER_ERROR_INJECTION
1776 tristate "Notifier error injection"
1777 depends on DEBUG_KERNEL
1780 This option provides the ability to inject artificial errors to
1781 specified notifier chain callbacks. It is useful to test the error
1782 handling of notifier call chain failures.
1786 config PM_NOTIFIER_ERROR_INJECT
1787 tristate "PM notifier error injection module"
1788 depends on PM && NOTIFIER_ERROR_INJECTION
1789 default m if PM_DEBUG
1791 This option provides the ability to inject artificial errors to
1792 PM notifier chain callbacks. It is controlled through debugfs
1793 interface /sys/kernel/debug/notifier-error-inject/pm
1795 If the notifier call chain should be failed with some events
1796 notified, write the error code to "actions/<notifier event>/error".
1798 Example: Inject PM suspend error (-12 = -ENOMEM)
1800 # cd /sys/kernel/debug/notifier-error-inject/pm/
1801 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1802 # echo mem > /sys/power/state
1803 bash: echo: write error: Cannot allocate memory
1805 To compile this code as a module, choose M here: the module will
1806 be called pm-notifier-error-inject.
1810 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1811 tristate "OF reconfig notifier error injection module"
1812 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1814 This option provides the ability to inject artificial errors to
1815 OF reconfig notifier chain callbacks. It is controlled
1816 through debugfs interface under
1817 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1819 If the notifier call chain should be failed with some events
1820 notified, write the error code to "actions/<notifier event>/error".
1822 To compile this code as a module, choose M here: the module will
1823 be called of-reconfig-notifier-error-inject.
1827 config NETDEV_NOTIFIER_ERROR_INJECT
1828 tristate "Netdev notifier error injection module"
1829 depends on NET && NOTIFIER_ERROR_INJECTION
1831 This option provides the ability to inject artificial errors to
1832 netdevice notifier chain callbacks. It is controlled through debugfs
1833 interface /sys/kernel/debug/notifier-error-inject/netdev
1835 If the notifier call chain should be failed with some events
1836 notified, write the error code to "actions/<notifier event>/error".
1838 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1840 # cd /sys/kernel/debug/notifier-error-inject/netdev
1841 # echo -22 > actions/NETDEV_CHANGEMTU/error
1842 # ip link set eth0 mtu 1024
1843 RTNETLINK answers: Invalid argument
1845 To compile this code as a module, choose M here: the module will
1846 be called netdev-notifier-error-inject.
1850 config FUNCTION_ERROR_INJECTION
1852 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1854 config FAULT_INJECTION
1855 bool "Fault-injection framework"
1856 depends on DEBUG_KERNEL
1858 Provide fault-injection framework.
1859 For more details, see Documentation/fault-injection/.
1862 bool "Fault-injection capability for kmalloc"
1863 depends on FAULT_INJECTION
1864 depends on SLAB || SLUB
1866 Provide fault-injection capability for kmalloc.
1868 config FAIL_PAGE_ALLOC
1869 bool "Fault-injection capability for alloc_pages()"
1870 depends on FAULT_INJECTION
1872 Provide fault-injection capability for alloc_pages().
1874 config FAULT_INJECTION_USERCOPY
1875 bool "Fault injection capability for usercopy functions"
1876 depends on FAULT_INJECTION
1878 Provides fault-injection capability to inject failures
1879 in usercopy functions (copy_from_user(), get_user(), ...).
1881 config FAIL_MAKE_REQUEST
1882 bool "Fault-injection capability for disk IO"
1883 depends on FAULT_INJECTION && BLOCK
1885 Provide fault-injection capability for disk IO.
1887 config FAIL_IO_TIMEOUT
1888 bool "Fault-injection capability for faking disk interrupts"
1889 depends on FAULT_INJECTION && BLOCK
1891 Provide fault-injection capability on end IO handling. This
1892 will make the block layer "forget" an interrupt as configured,
1893 thus exercising the error handling.
1895 Only works with drivers that use the generic timeout handling,
1896 for others it won't do anything.
1899 bool "Fault-injection capability for futexes"
1901 depends on FAULT_INJECTION && FUTEX
1903 Provide fault-injection capability for futexes.
1905 config FAULT_INJECTION_DEBUG_FS
1906 bool "Debugfs entries for fault-injection capabilities"
1907 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1909 Enable configuration of fault-injection capabilities via debugfs.
1911 config FAIL_FUNCTION
1912 bool "Fault-injection capability for functions"
1913 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1915 Provide function-based fault-injection capability.
1916 This will allow you to override a specific function with a return
1917 with given return value. As a result, function caller will see
1918 an error value and have to handle it. This is useful to test the
1919 error handling in various subsystems.
1921 config FAIL_MMC_REQUEST
1922 bool "Fault-injection capability for MMC IO"
1923 depends on FAULT_INJECTION_DEBUG_FS && MMC
1925 Provide fault-injection capability for MMC IO.
1926 This will make the mmc core return data errors. This is
1927 useful to test the error handling in the mmc block device
1928 and to test how the mmc host driver handles retries from
1932 bool "Fault-injection capability for SunRPC"
1933 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1935 Provide fault-injection capability for SunRPC and
1938 config FAULT_INJECTION_STACKTRACE_FILTER
1939 bool "stacktrace filter for fault-injection capabilities"
1940 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1943 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1945 Provide stacktrace filter for fault-injection capabilities
1947 config ARCH_HAS_KCOV
1950 An architecture should select this when it can successfully
1951 build and run with CONFIG_KCOV. This typically requires
1952 disabling instrumentation for some early boot code.
1954 config CC_HAS_SANCOV_TRACE_PC
1955 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1959 bool "Code coverage for fuzzing"
1960 depends on ARCH_HAS_KCOV
1961 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1962 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
1963 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
1965 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1966 select OBJTOOL if HAVE_NOINSTR_HACK
1968 KCOV exposes kernel code coverage information in a form suitable
1969 for coverage-guided fuzzing (randomized testing).
1971 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1972 different machines and across reboots. If you need stable PC values,
1973 disable RANDOMIZE_BASE.
1975 For more details, see Documentation/dev-tools/kcov.rst.
1977 config KCOV_ENABLE_COMPARISONS
1978 bool "Enable comparison operands collection by KCOV"
1980 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
1982 KCOV also exposes operands of every comparison in the instrumented
1983 code along with operand sizes and PCs of the comparison instructions.
1984 These operands can be used by fuzzing engines to improve the quality
1985 of fuzzing coverage.
1987 config KCOV_INSTRUMENT_ALL
1988 bool "Instrument all code by default"
1992 If you are doing generic system call fuzzing (like e.g. syzkaller),
1993 then you will want to instrument the whole kernel and you should
1994 say y here. If you are doing more targeted fuzzing (like e.g.
1995 filesystem fuzzing with AFL) then you will want to enable coverage
1996 for more specific subsets of files, and should say n here.
1998 config KCOV_IRQ_AREA_SIZE
1999 hex "Size of interrupt coverage collection area in words"
2003 KCOV uses preallocated per-cpu areas to collect coverage from
2004 soft interrupts. This specifies the size of those areas in the
2005 number of unsigned long words.
2007 menuconfig RUNTIME_TESTING_MENU
2008 bool "Runtime Testing"
2011 if RUNTIME_TESTING_MENU
2014 tristate "Linux Kernel Dump Test Tool Module"
2017 This module enables testing of the different dumping mechanisms by
2018 inducing system failures at predefined crash points.
2019 If you don't need it: say N
2020 Choose M here to compile this code as a module. The module will be
2023 Documentation on how to use the module can be found in
2024 Documentation/fault-injection/provoke-crashes.rst
2026 config TEST_LIST_SORT
2027 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2029 default KUNIT_ALL_TESTS
2031 Enable this to turn on 'list_sort()' function test. This test is
2032 executed only once during system boot (so affects only boot time),
2033 or at module load time.
2037 config TEST_MIN_HEAP
2038 tristate "Min heap test"
2039 depends on DEBUG_KERNEL || m
2041 Enable this to turn on min heap function tests. This test is
2042 executed only once during system boot (so affects only boot time),
2043 or at module load time.
2048 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2050 default KUNIT_ALL_TESTS
2052 This option enables the self-test function of 'sort()' at boot,
2053 or at module load time.
2058 tristate "64bit/32bit division and modulo test"
2059 depends on DEBUG_KERNEL || m
2061 Enable this to turn on 'do_div()' function test. This test is
2062 executed only once during system boot (so affects only boot time),
2063 or at module load time.
2067 config KPROBES_SANITY_TEST
2068 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2069 depends on DEBUG_KERNEL
2072 default KUNIT_ALL_TESTS
2074 This option provides for testing basic kprobes functionality on
2075 boot. Samples of kprobe and kretprobe are inserted and
2076 verified for functionality.
2078 Say N if you are unsure.
2080 config FPROBE_SANITY_TEST
2081 bool "Self test for fprobe"
2082 depends on DEBUG_KERNEL
2086 This option will enable testing the fprobe when the system boot.
2087 A series of tests are made to verify that the fprobe is functioning
2090 Say N if you are unsure.
2092 config BACKTRACE_SELF_TEST
2093 tristate "Self test for the backtrace code"
2094 depends on DEBUG_KERNEL
2096 This option provides a kernel module that can be used to test
2097 the kernel stack backtrace code. This option is not useful
2098 for distributions or general kernels, but only for kernel
2099 developers working on architecture code.
2101 Note that if you want to also test saved backtraces, you will
2102 have to enable STACKTRACE as well.
2104 Say N if you are unsure.
2106 config TEST_REF_TRACKER
2107 tristate "Self test for reference tracker"
2108 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2111 This option provides a kernel module performing tests
2112 using reference tracker infrastructure.
2114 Say N if you are unsure.
2117 tristate "Red-Black tree test"
2118 depends on DEBUG_KERNEL
2120 A benchmark measuring the performance of the rbtree library.
2121 Also includes rbtree invariant checks.
2123 config REED_SOLOMON_TEST
2124 tristate "Reed-Solomon library test"
2125 depends on DEBUG_KERNEL || m
2127 select REED_SOLOMON_ENC16
2128 select REED_SOLOMON_DEC16
2130 This option enables the self-test function of rslib at boot,
2131 or at module load time.
2135 config INTERVAL_TREE_TEST
2136 tristate "Interval tree test"
2137 depends on DEBUG_KERNEL
2138 select INTERVAL_TREE
2140 A benchmark measuring the performance of the interval tree library
2143 tristate "Per cpu operations test"
2144 depends on m && DEBUG_KERNEL
2146 Enable this option to build test module which validates per-cpu
2151 config ATOMIC64_SELFTEST
2152 tristate "Perform an atomic64_t self-test"
2154 Enable this option to test the atomic64_t functions at boot or
2155 at module load time.
2159 config ASYNC_RAID6_TEST
2160 tristate "Self test for hardware accelerated raid6 recovery"
2161 depends on ASYNC_RAID6_RECOV
2164 This is a one-shot self test that permutes through the
2165 recovery of all the possible two disk failure scenarios for a
2166 N-disk array. Recovery is performed with the asynchronous
2167 raid6 recovery routines, and will optionally use an offload
2168 engine if one is available.
2173 tristate "Test functions located in the hexdump module at runtime"
2175 config STRING_SELFTEST
2176 tristate "Test string functions at runtime"
2178 config TEST_STRING_HELPERS
2179 tristate "Test functions located in the string_helpers module at runtime"
2182 tristate "Test strscpy*() family of functions at runtime"
2185 tristate "Test kstrto*() family of functions at runtime"
2188 tristate "Test printf() family of functions at runtime"
2191 tristate "Test scanf() family of functions at runtime"
2194 tristate "Test bitmap_*() family of functions at runtime"
2196 Enable this option to test the bitmap functions at boot.
2201 tristate "Test functions located in the uuid module at runtime"
2204 tristate "Test the XArray code at runtime"
2206 config TEST_RHASHTABLE
2207 tristate "Perform selftest on resizable hash table"
2209 Enable this option to test the rhashtable functions at boot.
2214 tristate "Perform selftest on siphash functions"
2216 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2217 functions on boot (or module load).
2219 This is intended to help people writing architecture-specific
2220 optimized versions. If unsure, say N.
2223 tristate "Perform selftest on IDA functions"
2226 tristate "Perform selftest on priority array manager"
2229 Enable this option to test priority array manager on boot
2234 config TEST_IRQ_TIMINGS
2235 bool "IRQ timings selftest"
2236 depends on IRQ_TIMINGS
2238 Enable this option to test the irq timings code on boot.
2243 tristate "Test module loading with 'hello world' module"
2246 This builds the "test_module" module that emits "Hello, world"
2247 on printk when loaded. It is designed to be used for basic
2248 evaluation of the module loading subsystem (for example when
2249 validating module verification). It lacks any extra dependencies,
2250 and will not normally be loaded by the system unless explicitly
2256 tristate "Test module for compilation of bitops operations"
2259 This builds the "test_bitops" module that is much like the
2260 TEST_LKM module except that it does a basic exercise of the
2261 set/clear_bit macros and get_count_order/long to make sure there are
2262 no compiler warnings from C=1 sparse checker or -Wextra
2263 compilations. It has no dependencies and doesn't run or load unless
2264 explicitly requested by name. for example: modprobe test_bitops.
2269 tristate "Test module for stress/performance analysis of vmalloc allocator"
2274 This builds the "test_vmalloc" module that should be used for
2275 stress and performance analysis. So, any new change for vmalloc
2276 subsystem can be evaluated from performance and stability point
2281 config TEST_USER_COPY
2282 tristate "Test user/kernel boundary protections"
2285 This builds the "test_user_copy" module that runs sanity checks
2286 on the copy_to/from_user infrastructure, making sure basic
2287 user/kernel boundary testing is working. If it fails to load,
2288 a regression has been detected in the user/kernel memory boundary
2294 tristate "Test BPF filter functionality"
2297 This builds the "test_bpf" module that runs various test vectors
2298 against the BPF interpreter or BPF JIT compiler depending on the
2299 current setting. This is in particular useful for BPF JIT compiler
2300 development, but also to run regression tests against changes in
2301 the interpreter code. It also enables test stubs for eBPF maps and
2302 verifier used by user space verifier testsuite.
2306 config TEST_BLACKHOLE_DEV
2307 tristate "Test blackhole netdev functionality"
2310 This builds the "test_blackhole_dev" module that validates the
2311 data path through this blackhole netdev.
2315 config FIND_BIT_BENCHMARK
2316 tristate "Test find_bit functions"
2318 This builds the "test_find_bit" module that measure find_*_bit()
2319 functions performance.
2323 config TEST_FIRMWARE
2324 tristate "Test firmware loading via userspace interface"
2325 depends on FW_LOADER
2327 This builds the "test_firmware" module that creates a userspace
2328 interface for testing firmware loading. This can be used to
2329 control the triggering of firmware loading without needing an
2330 actual firmware-using device. The contents can be rechecked by
2336 tristate "sysctl test driver"
2337 depends on PROC_SYSCTL
2339 This builds the "test_sysctl" module. This driver enables to test the
2340 proc sysctl interfaces available to drivers safely without affecting
2341 production knobs which might alter system functionality.
2345 config BITFIELD_KUNIT
2346 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2348 default KUNIT_ALL_TESTS
2350 Enable this option to test the bitfield functions at boot.
2352 KUnit tests run during boot and output the results to the debug log
2353 in TAP format (http://testanything.org/). Only useful for kernel devs
2354 running the KUnit test harness, and not intended for inclusion into a
2357 For more information on KUnit and unit tests in general please refer
2358 to the KUnit documentation in Documentation/dev-tools/kunit/.
2362 config HASH_KUNIT_TEST
2363 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2365 default KUNIT_ALL_TESTS
2367 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2368 integer (<linux/hash.h>) hash functions on boot.
2370 KUnit tests run during boot and output the results to the debug log
2371 in TAP format (https://testanything.org/). Only useful for kernel devs
2372 running the KUnit test harness, and not intended for inclusion into a
2375 For more information on KUnit and unit tests in general please refer
2376 to the KUnit documentation in Documentation/dev-tools/kunit/.
2378 This is intended to help people writing architecture-specific
2379 optimized versions. If unsure, say N.
2381 config RESOURCE_KUNIT_TEST
2382 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2384 default KUNIT_ALL_TESTS
2386 This builds the resource API unit test.
2387 Tests the logic of API provided by resource.c and ioport.h.
2388 For more information on KUnit and unit tests in general please refer
2389 to the KUnit documentation in Documentation/dev-tools/kunit/.
2393 config SYSCTL_KUNIT_TEST
2394 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2396 default KUNIT_ALL_TESTS
2398 This builds the proc sysctl unit test, which runs on boot.
2399 Tests the API contract and implementation correctness of sysctl.
2400 For more information on KUnit and unit tests in general please refer
2401 to the KUnit documentation in Documentation/dev-tools/kunit/.
2405 config LIST_KUNIT_TEST
2406 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2408 default KUNIT_ALL_TESTS
2410 This builds the linked list KUnit test suite.
2411 It tests that the API and basic functionality of the list_head type
2412 and associated macros.
2414 KUnit tests run during boot and output the results to the debug log
2415 in TAP format (https://testanything.org/). Only useful for kernel devs
2416 running the KUnit test harness, and not intended for inclusion into a
2419 For more information on KUnit and unit tests in general please refer
2420 to the KUnit documentation in Documentation/dev-tools/kunit/.
2424 config LINEAR_RANGES_TEST
2425 tristate "KUnit test for linear_ranges"
2427 select LINEAR_RANGES
2429 This builds the linear_ranges unit test, which runs on boot.
2430 Tests the linear_ranges logic correctness.
2431 For more information on KUnit and unit tests in general please refer
2432 to the KUnit documentation in Documentation/dev-tools/kunit/.
2436 config CMDLINE_KUNIT_TEST
2437 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2439 default KUNIT_ALL_TESTS
2441 This builds the cmdline API unit test.
2442 Tests the logic of API provided by cmdline.c.
2443 For more information on KUnit and unit tests in general please refer
2444 to the KUnit documentation in Documentation/dev-tools/kunit/.
2449 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2451 default KUNIT_ALL_TESTS
2453 This builds the bits unit test.
2454 Tests the logic of macros defined in bits.h.
2455 For more information on KUnit and unit tests in general please refer
2456 to the KUnit documentation in Documentation/dev-tools/kunit/.
2460 config SLUB_KUNIT_TEST
2461 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2462 depends on SLUB_DEBUG && KUNIT
2463 default KUNIT_ALL_TESTS
2465 This builds SLUB allocator unit test.
2466 Tests SLUB cache debugging functionality.
2467 For more information on KUnit and unit tests in general please refer
2468 to the KUnit documentation in Documentation/dev-tools/kunit/.
2472 config RATIONAL_KUNIT_TEST
2473 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2474 depends on KUNIT && RATIONAL
2475 default KUNIT_ALL_TESTS
2477 This builds the rational math unit test.
2478 For more information on KUnit and unit tests in general please refer
2479 to the KUnit documentation in Documentation/dev-tools/kunit/.
2483 config MEMCPY_KUNIT_TEST
2484 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2486 default KUNIT_ALL_TESTS
2488 Builds unit tests for memcpy(), memmove(), and memset() functions.
2489 For more information on KUnit and unit tests in general please refer
2490 to the KUnit documentation in Documentation/dev-tools/kunit/.
2494 config OVERFLOW_KUNIT_TEST
2495 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2497 default KUNIT_ALL_TESTS
2499 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2502 For more information on KUnit and unit tests in general please refer
2503 to the KUnit documentation in Documentation/dev-tools/kunit/.
2507 config STACKINIT_KUNIT_TEST
2508 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2510 default KUNIT_ALL_TESTS
2512 Test if the kernel is zero-initializing stack variables and
2513 padding. Coverage is controlled by compiler flags,
2514 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2515 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2516 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2519 tristate "udelay test driver"
2521 This builds the "udelay_test" module that helps to make sure
2522 that udelay() is working properly.
2526 config TEST_STATIC_KEYS
2527 tristate "Test static keys"
2530 Test the static key interfaces.
2535 tristate "kmod stress tester"
2537 depends on NETDEVICES && NET_CORE && INET # for TUN
2539 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2545 Test the kernel's module loading mechanism: kmod. kmod implements
2546 support to load modules using the Linux kernel's usermode helper.
2547 This test provides a series of tests against kmod.
2549 Although technically you can either build test_kmod as a module or
2550 into the kernel we disallow building it into the kernel since
2551 it stress tests request_module() and this will very likely cause
2552 some issues by taking over precious threads available from other
2553 module load requests, ultimately this could be fatal.
2557 tools/testing/selftests/kmod/kmod.sh --help
2561 config TEST_DEBUG_VIRTUAL
2562 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2563 depends on DEBUG_VIRTUAL
2565 Test the kernel's ability to detect incorrect calls to
2566 virt_to_phys() done against the non-linear part of the
2567 kernel's virtual address map.
2571 config TEST_MEMCAT_P
2572 tristate "Test memcat_p() helper function"
2574 Test the memcat_p() helper for correctly merging two
2575 pointer arrays together.
2579 config TEST_LIVEPATCH
2580 tristate "Test livepatching"
2582 depends on DYNAMIC_DEBUG
2583 depends on LIVEPATCH
2586 Test kernel livepatching features for correctness. The tests will
2587 load test modules that will be livepatched in various scenarios.
2589 To run all the livepatching tests:
2591 make -C tools/testing/selftests TARGETS=livepatch run_tests
2593 Alternatively, individual tests may be invoked:
2595 tools/testing/selftests/livepatch/test-callbacks.sh
2596 tools/testing/selftests/livepatch/test-livepatch.sh
2597 tools/testing/selftests/livepatch/test-shadow-vars.sh
2602 tristate "Perform selftest on object aggreration manager"
2606 Enable this option to test object aggregation manager on boot
2610 tristate "Test heap/page initialization"
2612 Test if the kernel is zero-initializing heap and page allocations.
2613 This can be useful to test init_on_alloc and init_on_free features.
2618 tristate "Test HMM (Heterogeneous Memory Management)"
2619 depends on TRANSPARENT_HUGEPAGE
2620 depends on DEVICE_PRIVATE
2624 This is a pseudo device driver solely for testing HMM.
2625 Say M here if you want to build the HMM test module.
2626 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2630 config TEST_FREE_PAGES
2631 tristate "Test freeing pages"
2633 Test that a memory leak does not occur due to a race between
2634 freeing a block of pages and a speculative page reference.
2635 Loading this module is safe if your kernel has the bug fixed.
2636 If the bug is not fixed, it will leak gigabytes of memory and
2637 probably OOM your system.
2640 tristate "Test floating point operations in kernel space"
2641 depends on X86 && !KCOV_INSTRUMENT_ALL
2643 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2644 which will trigger a sequence of floating point operations. This is used
2645 for self-testing floating point control register setting in
2650 config TEST_CLOCKSOURCE_WATCHDOG
2651 tristate "Test clocksource watchdog in kernel space"
2652 depends on CLOCKSOURCE_WATCHDOG
2654 Enable this option to create a kernel module that will trigger
2655 a test of the clocksource watchdog. This module may be loaded
2656 via modprobe or insmod in which case it will run upon being
2657 loaded, or it may be built in, in which case it will run
2662 endif # RUNTIME_TESTING_MENU
2664 config ARCH_USE_MEMTEST
2667 An architecture should select this when it uses early_memtest()
2668 during boot process.
2672 depends on ARCH_USE_MEMTEST
2674 This option adds a kernel parameter 'memtest', which allows memtest
2675 to be set and executed.
2676 memtest=0, mean disabled; -- default
2677 memtest=1, mean do 1 test pattern;
2679 memtest=17, mean do 17 test patterns.
2680 If you are unsure how to answer this question, answer N.
2684 config HYPERV_TESTING
2685 bool "Microsoft Hyper-V driver testing"
2687 depends on HYPERV && DEBUG_FS
2689 Select this option to enable Hyper-V vmbus testing.
2691 endmenu # "Kernel Testing and Coverage"
2693 source "Documentation/Kconfig"
2695 endmenu # Kernel hacking
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