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"
268 Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+.
270 If you have consumers of DWARF debug info that are not ready for
271 newer revisions of DWARF, you may wish to choose this or have your
274 config DEBUG_INFO_DWARF5
275 bool "Generate DWARF Version 5 debuginfo"
277 depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)))
279 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
280 5.0+ accepts the -gdwarf-5 flag but only had partial support for some
281 draft features until 7.0), and gdb 8.0+.
283 Changes to the structure of debug info in Version 5 allow for around
284 15-18% savings in resulting image and debug info section sizes as
285 compared to DWARF Version 4. DWARF Version 5 standardizes previous
286 extensions such as accelerators for symbol indexing and the format
287 for fission (.dwo/.dwp) files. Users may not want to select this
288 config if they rely on tooling that has not yet been updated to
289 support DWARF Version 5.
291 endchoice # "Debug information"
295 config DEBUG_INFO_REDUCED
296 bool "Reduce debugging information"
298 If you say Y here gcc is instructed to generate less debugging
299 information for structure types. This means that tools that
300 need full debugging information (like kgdb or systemtap) won't
301 be happy. But if you merely need debugging information to
302 resolve line numbers there is no loss. Advantage is that
303 build directory object sizes shrink dramatically over a full
304 DEBUG_INFO build and compile times are reduced too.
305 Only works with newer gcc versions.
307 config DEBUG_INFO_COMPRESSED
308 bool "Compressed debugging information"
309 depends on $(cc-option,-gz=zlib)
310 depends on $(ld-option,--compress-debug-sections=zlib)
312 Compress the debug information using zlib. Requires GCC 5.0+ or Clang
313 5.0+, binutils 2.26+, and zlib.
315 Users of dpkg-deb via scripts/package/builddeb may find an increase in
316 size of their debug .deb packages with this config set, due to the
317 debug info being compressed with zlib, then the object files being
318 recompressed with a different compression scheme. But this is still
319 preferable to setting $KDEB_COMPRESS to "none" which would be even
322 config DEBUG_INFO_SPLIT
323 bool "Produce split debuginfo in .dwo files"
324 depends on $(cc-option,-gsplit-dwarf)
326 Generate debug info into separate .dwo files. This significantly
327 reduces the build directory size for builds with DEBUG_INFO,
328 because it stores the information only once on disk in .dwo
329 files instead of multiple times in object files and executables.
330 In addition the debug information is also compressed.
332 Requires recent gcc (4.7+) and recent gdb/binutils.
333 Any tool that packages or reads debug information would need
334 to know about the .dwo files and include them.
335 Incompatible with older versions of ccache.
337 config DEBUG_INFO_BTF
338 bool "Generate BTF typeinfo"
339 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
340 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
341 depends on BPF_SYSCALL
342 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121
344 Generate deduplicated BTF type information from DWARF debug info.
345 Turning this on expects presence of pahole tool, which will convert
346 DWARF type info into equivalent deduplicated BTF type info.
348 config PAHOLE_HAS_SPLIT_BTF
349 def_bool PAHOLE_VERSION >= 119
351 config PAHOLE_HAS_BTF_TAG
352 def_bool PAHOLE_VERSION >= 123
353 depends on CC_IS_CLANG
355 Decide whether pahole emits btf_tag attributes (btf_type_tag and
356 btf_decl_tag) or not. Currently only clang compiler implements
357 these attributes, so make the config depend on CC_IS_CLANG.
359 config DEBUG_INFO_BTF_MODULES
361 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
363 Generate compact split BTF type information for kernel modules.
365 config MODULE_ALLOW_BTF_MISMATCH
366 bool "Allow loading modules with non-matching BTF type info"
367 depends on DEBUG_INFO_BTF_MODULES
369 For modules whose split BTF does not match vmlinux, load without
370 BTF rather than refusing to load. The default behavior with
371 module BTF enabled is to reject modules with such mismatches;
372 this option will still load module BTF where possible but ignore
373 it when a mismatch is found.
376 bool "Provide GDB scripts for kernel debugging"
378 This creates the required links to GDB helper scripts in the
379 build directory. If you load vmlinux into gdb, the helper
380 scripts will be automatically imported by gdb as well, and
381 additional functions are available to analyze a Linux kernel
382 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
388 int "Warn for stack frames larger than"
390 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
391 default 2048 if PARISC
392 default 1536 if (!64BIT && XTENSA)
393 default 1024 if !64BIT
394 default 2048 if 64BIT
396 Tell gcc to warn at build time for stack frames larger than this.
397 Setting this too low will cause a lot of warnings.
398 Setting it to 0 disables the warning.
400 config STRIP_ASM_SYMS
401 bool "Strip assembler-generated symbols during link"
404 Strip internal assembler-generated symbols during a link (symbols
405 that look like '.Lxxx') so they don't pollute the output of
406 get_wchan() and suchlike.
409 bool "Generate readable assembler code"
410 depends on DEBUG_KERNEL
413 Disable some compiler optimizations that tend to generate human unreadable
414 assembler output. This may make the kernel slightly slower, but it helps
415 to keep kernel developers who have to stare a lot at assembler listings
418 config HEADERS_INSTALL
419 bool "Install uapi headers to usr/include"
422 This option will install uapi headers (headers exported to user-space)
423 into the usr/include directory for use during the kernel build.
424 This is unneeded for building the kernel itself, but needed for some
425 user-space program samples. It is also needed by some features such
426 as uapi header sanity checks.
428 config DEBUG_SECTION_MISMATCH
429 bool "Enable full Section mismatch analysis"
432 The section mismatch analysis checks if there are illegal
433 references from one section to another section.
434 During linktime or runtime, some sections are dropped;
435 any use of code/data previously in these sections would
436 most likely result in an oops.
437 In the code, functions and variables are annotated with
438 __init,, etc. (see the full list in include/linux/init.h),
439 which results in the code/data being placed in specific sections.
440 The section mismatch analysis is always performed after a full
441 kernel build, and enabling this option causes the following
442 additional step to occur:
443 - Add the option -fno-inline-functions-called-once to gcc commands.
444 When inlining a function annotated with __init in a non-init
445 function, we would lose the section information and thus
446 the analysis would not catch the illegal reference.
447 This option tells gcc to inline less (but it does result in
450 config SECTION_MISMATCH_WARN_ONLY
451 bool "Make section mismatch errors non-fatal"
454 If you say N here, the build process will fail if there are any
455 section mismatch, instead of just throwing warnings.
459 config DEBUG_FORCE_FUNCTION_ALIGN_64B
460 bool "Force all function address 64B aligned"
461 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC)
463 There are cases that a commit from one domain changes the function
464 address alignment of other domains, and cause magic performance
465 bump (regression or improvement). Enable this option will help to
466 verify if the bump is caused by function alignment changes, while
467 it will slightly increase the kernel size and affect icache usage.
469 It is mainly for debug and performance tuning use.
472 # Select this config option from the architecture Kconfig, if it
473 # is preferred to always offer frame pointers as a config
474 # option on the architecture (regardless of KERNEL_DEBUG):
476 config ARCH_WANT_FRAME_POINTERS
480 bool "Compile the kernel with frame pointers"
481 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
482 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
484 If you say Y here the resulting kernel image will be slightly
485 larger and slower, but it gives very useful debugging information
486 in case of kernel bugs. (precise oopses/stacktraces/warnings)
491 config STACK_VALIDATION
492 bool "Compile-time stack metadata validation"
493 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
497 Validate frame pointer rules at compile-time. This helps ensure that
498 runtime stack traces are more reliable.
500 For more information, see
501 tools/objtool/Documentation/objtool.txt.
503 config NOINSTR_VALIDATION
505 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
510 bool "Generate vmlinux.map file when linking"
513 Selecting this option will pass "-Map=vmlinux.map" to ld
514 when linking vmlinux. That file can be useful for verifying
515 and debugging magic section games, and for seeing which
516 pieces of code get eliminated with
517 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
519 config DEBUG_FORCE_WEAK_PER_CPU
520 bool "Force weak per-cpu definitions"
521 depends on DEBUG_KERNEL
523 s390 and alpha require percpu variables in modules to be
524 defined weak to work around addressing range issue which
525 puts the following two restrictions on percpu variable
528 1. percpu symbols must be unique whether static or not
529 2. percpu variables can't be defined inside a function
531 To ensure that generic code follows the above rules, this
532 option forces all percpu variables to be defined as weak.
534 endmenu # "Compiler options"
536 menu "Generic Kernel Debugging Instruments"
539 bool "Magic SysRq key"
542 If you say Y here, you will have some control over the system even
543 if the system crashes for example during kernel debugging (e.g., you
544 will be able to flush the buffer cache to disk, reboot the system
545 immediately or dump some status information). This is accomplished
546 by pressing various keys while holding SysRq (Alt+PrintScreen). It
547 also works on a serial console (on PC hardware at least), if you
548 send a BREAK and then within 5 seconds a command keypress. The
549 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
550 Don't say Y unless you really know what this hack does.
552 config MAGIC_SYSRQ_DEFAULT_ENABLE
553 hex "Enable magic SysRq key functions by default"
554 depends on MAGIC_SYSRQ
557 Specifies which SysRq key functions are enabled by default.
558 This may be set to 1 or 0 to enable or disable them all, or
559 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
561 config MAGIC_SYSRQ_SERIAL
562 bool "Enable magic SysRq key over serial"
563 depends on MAGIC_SYSRQ
566 Many embedded boards have a disconnected TTL level serial which can
567 generate some garbage that can lead to spurious false sysrq detects.
568 This option allows you to decide whether you want to enable the
571 config MAGIC_SYSRQ_SERIAL_SEQUENCE
572 string "Char sequence that enables magic SysRq over serial"
573 depends on MAGIC_SYSRQ_SERIAL
576 Specifies a sequence of characters that can follow BREAK to enable
577 SysRq on a serial console.
579 If unsure, leave an empty string and the option will not be enabled.
582 bool "Debug Filesystem"
584 debugfs is a virtual file system that kernel developers use to put
585 debugging files into. Enable this option to be able to read and
586 write to these files.
588 For detailed documentation on the debugfs API, see
589 Documentation/filesystems/.
594 prompt "Debugfs default access"
596 default DEBUG_FS_ALLOW_ALL
598 This selects the default access restrictions for debugfs.
599 It can be overridden with kernel command line option
600 debugfs=[on,no-mount,off]. The restrictions apply for API access
601 and filesystem registration.
603 config DEBUG_FS_ALLOW_ALL
606 No restrictions apply. Both API and filesystem registration
607 is on. This is the normal default operation.
609 config DEBUG_FS_DISALLOW_MOUNT
610 bool "Do not register debugfs as filesystem"
612 The API is open but filesystem is not loaded. Clients can still do
613 their work and read with debug tools that do not need
616 config DEBUG_FS_ALLOW_NONE
619 Access is off. Clients get -PERM when trying to create nodes in
620 debugfs tree and debugfs is not registered as a filesystem.
621 Client can then back-off or continue without debugfs access.
625 source "lib/Kconfig.kgdb"
626 source "lib/Kconfig.ubsan"
627 source "lib/Kconfig.kcsan"
631 menu "Networking Debugging"
633 source "net/Kconfig.debug"
635 endmenu # "Networking Debugging"
637 menu "Memory Debugging"
639 source "mm/Kconfig.debug"
642 bool "Debug object operations"
643 depends on DEBUG_KERNEL
645 If you say Y here, additional code will be inserted into the
646 kernel to track the life time of various objects and validate
647 the operations on those objects.
649 config DEBUG_OBJECTS_SELFTEST
650 bool "Debug objects selftest"
651 depends on DEBUG_OBJECTS
653 This enables the selftest of the object debug code.
655 config DEBUG_OBJECTS_FREE
656 bool "Debug objects in freed memory"
657 depends on DEBUG_OBJECTS
659 This enables checks whether a k/v free operation frees an area
660 which contains an object which has not been deactivated
661 properly. This can make kmalloc/kfree-intensive workloads
664 config DEBUG_OBJECTS_TIMERS
665 bool "Debug timer objects"
666 depends on DEBUG_OBJECTS
668 If you say Y here, additional code will be inserted into the
669 timer routines to track the life time of timer objects and
670 validate the timer operations.
672 config DEBUG_OBJECTS_WORK
673 bool "Debug work objects"
674 depends on DEBUG_OBJECTS
676 If you say Y here, additional code will be inserted into the
677 work queue routines to track the life time of work objects and
678 validate the work operations.
680 config DEBUG_OBJECTS_RCU_HEAD
681 bool "Debug RCU callbacks objects"
682 depends on DEBUG_OBJECTS
684 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
686 config DEBUG_OBJECTS_PERCPU_COUNTER
687 bool "Debug percpu counter objects"
688 depends on DEBUG_OBJECTS
690 If you say Y here, additional code will be inserted into the
691 percpu counter routines to track the life time of percpu counter
692 objects and validate the percpu counter operations.
694 config DEBUG_OBJECTS_ENABLE_DEFAULT
695 int "debug_objects bootup default value (0-1)"
698 depends on DEBUG_OBJECTS
700 Debug objects boot parameter default value
702 config SHRINKER_DEBUG
703 bool "Enable shrinker debugging support"
706 Say Y to enable the shrinker debugfs interface which provides
707 visibility into the kernel memory shrinkers subsystem.
708 Disable it to avoid an extra memory footprint.
710 config HAVE_DEBUG_KMEMLEAK
713 config DEBUG_KMEMLEAK
714 bool "Kernel memory leak detector"
715 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
717 select STACKTRACE if STACKTRACE_SUPPORT
721 Say Y here if you want to enable the memory leak
722 detector. The memory allocation/freeing is traced in a way
723 similar to the Boehm's conservative garbage collector, the
724 difference being that the orphan objects are not freed but
725 only shown in /sys/kernel/debug/kmemleak. Enabling this
726 feature will introduce an overhead to memory
727 allocations. See Documentation/dev-tools/kmemleak.rst for more
730 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
731 of finding leaks due to the slab objects poisoning.
733 In order to access the kmemleak file, debugfs needs to be
734 mounted (usually at /sys/kernel/debug).
736 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
737 int "Kmemleak memory pool size"
738 depends on DEBUG_KMEMLEAK
742 Kmemleak must track all the memory allocations to avoid
743 reporting false positives. Since memory may be allocated or
744 freed before kmemleak is fully initialised, use a static pool
745 of metadata objects to track such callbacks. After kmemleak is
746 fully initialised, this memory pool acts as an emergency one
747 if slab allocations fail.
749 config DEBUG_KMEMLEAK_TEST
750 tristate "Simple test for the kernel memory leak detector"
751 depends on DEBUG_KMEMLEAK && m
753 This option enables a module that explicitly leaks memory.
757 config DEBUG_KMEMLEAK_DEFAULT_OFF
758 bool "Default kmemleak to off"
759 depends on DEBUG_KMEMLEAK
761 Say Y here to disable kmemleak by default. It can then be enabled
762 on the command line via kmemleak=on.
764 config DEBUG_KMEMLEAK_AUTO_SCAN
765 bool "Enable kmemleak auto scan thread on boot up"
767 depends on DEBUG_KMEMLEAK
769 Depending on the cpu, kmemleak scan may be cpu intensive and can
770 stall user tasks at times. This option enables/disables automatic
771 kmemleak scan at boot up.
773 Say N here to disable kmemleak auto scan thread to stop automatic
774 scanning. Disabling this option disables automatic reporting of
779 config DEBUG_STACK_USAGE
780 bool "Stack utilization instrumentation"
781 depends on DEBUG_KERNEL && !IA64
783 Enables the display of the minimum amount of free stack which each
784 task has ever had available in the sysrq-T and sysrq-P debug output.
786 This option will slow down process creation somewhat.
788 config SCHED_STACK_END_CHECK
789 bool "Detect stack corruption on calls to schedule()"
790 depends on DEBUG_KERNEL
793 This option checks for a stack overrun on calls to schedule().
794 If the stack end location is found to be over written always panic as
795 the content of the corrupted region can no longer be trusted.
796 This is to ensure no erroneous behaviour occurs which could result in
797 data corruption or a sporadic crash at a later stage once the region
798 is examined. The runtime overhead introduced is minimal.
800 config ARCH_HAS_DEBUG_VM_PGTABLE
803 An architecture should select this when it can successfully
804 build and run DEBUG_VM_PGTABLE.
808 depends on DEBUG_KERNEL
810 Enable this to turn on extended checks in the virtual-memory system
811 that may impact performance.
815 config DEBUG_VM_VMACACHE
816 bool "Debug VMA caching"
819 Enable this to turn on VMA caching debug information. Doing so
820 can cause significant overhead, so only enable it in non-production
826 bool "Debug VM red-black trees"
829 Enable VM red-black tree debugging information and extra validations.
833 config DEBUG_VM_PGFLAGS
834 bool "Debug page-flags operations"
837 Enables extra validation on page flags operations.
841 config DEBUG_VM_PGTABLE
842 bool "Debug arch page table for semantics compliance"
844 depends on ARCH_HAS_DEBUG_VM_PGTABLE
845 default y if DEBUG_VM
847 This option provides a debug method which can be used to test
848 architecture page table helper functions on various platforms in
849 verifying if they comply with expected generic MM semantics. This
850 will help architecture code in making sure that any changes or
851 new additions of these helpers still conform to expected
852 semantics of the generic MM. Platforms will have to opt in for
853 this through ARCH_HAS_DEBUG_VM_PGTABLE.
857 config ARCH_HAS_DEBUG_VIRTUAL
861 bool "Debug VM translations"
862 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
864 Enable some costly sanity checks in virtual to page code. This can
865 catch mistakes with virt_to_page() and friends.
869 config DEBUG_NOMMU_REGIONS
870 bool "Debug the global anon/private NOMMU mapping region tree"
871 depends on DEBUG_KERNEL && !MMU
873 This option causes the global tree of anonymous and private mapping
874 regions to be regularly checked for invalid topology.
876 config DEBUG_MEMORY_INIT
877 bool "Debug memory initialisation" if EXPERT
880 Enable this for additional checks during memory initialisation.
881 The sanity checks verify aspects of the VM such as the memory model
882 and other information provided by the architecture. Verbose
883 information will be printed at KERN_DEBUG loglevel depending
884 on the mminit_loglevel= command-line option.
888 config MEMORY_NOTIFIER_ERROR_INJECT
889 tristate "Memory hotplug notifier error injection module"
890 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
892 This option provides the ability to inject artificial errors to
893 memory hotplug notifier chain callbacks. It is controlled through
894 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
896 If the notifier call chain should be failed with some events
897 notified, write the error code to "actions/<notifier event>/error".
899 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
901 # cd /sys/kernel/debug/notifier-error-inject/memory
902 # echo -12 > actions/MEM_GOING_OFFLINE/error
903 # echo offline > /sys/devices/system/memory/memoryXXX/state
904 bash: echo: write error: Cannot allocate memory
906 To compile this code as a module, choose M here: the module will
907 be called memory-notifier-error-inject.
911 config DEBUG_PER_CPU_MAPS
912 bool "Debug access to per_cpu maps"
913 depends on DEBUG_KERNEL
916 Say Y to verify that the per_cpu map being accessed has
917 been set up. This adds a fair amount of code to kernel memory
918 and decreases performance.
922 config DEBUG_KMAP_LOCAL
923 bool "Debug kmap_local temporary mappings"
924 depends on DEBUG_KERNEL && KMAP_LOCAL
926 This option enables additional error checking for the kmap_local
927 infrastructure. Disable for production use.
929 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
932 config DEBUG_KMAP_LOCAL_FORCE_MAP
933 bool "Enforce kmap_local temporary mappings"
934 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
936 select DEBUG_KMAP_LOCAL
938 This option enforces temporary mappings through the kmap_local
939 mechanism for non-highmem pages and on non-highmem systems.
940 Disable this for production systems!
943 bool "Highmem debugging"
944 depends on DEBUG_KERNEL && HIGHMEM
945 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
946 select DEBUG_KMAP_LOCAL
948 This option enables additional error checking for high memory
949 systems. Disable for production systems.
951 config HAVE_DEBUG_STACKOVERFLOW
954 config DEBUG_STACKOVERFLOW
955 bool "Check for stack overflows"
956 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
958 Say Y here if you want to check for overflows of kernel, IRQ
959 and exception stacks (if your architecture uses them). This
960 option will show detailed messages if free stack space drops
961 below a certain limit.
963 These kinds of bugs usually occur when call-chains in the
964 kernel get too deep, especially when interrupts are
967 Use this in cases where you see apparently random memory
968 corruption, especially if it appears in 'struct thread_info'
970 If in doubt, say "N".
972 source "lib/Kconfig.kasan"
973 source "lib/Kconfig.kfence"
975 endmenu # "Memory Debugging"
978 bool "Debug shared IRQ handlers"
979 depends on DEBUG_KERNEL
981 Enable this to generate a spurious interrupt just before a shared
982 interrupt handler is deregistered (generating one when registering
983 is currently disabled). Drivers need to handle this correctly. Some
984 don't and need to be caught.
986 menu "Debug Oops, Lockups and Hangs"
991 Say Y here to enable the kernel to panic when it oopses. This
992 has the same effect as setting oops=panic on the kernel command
995 This feature is useful to ensure that the kernel does not do
996 anything erroneous after an oops which could result in data
997 corruption or other issues.
1001 config PANIC_ON_OOPS_VALUE
1004 default 0 if !PANIC_ON_OOPS
1005 default 1 if PANIC_ON_OOPS
1007 config PANIC_TIMEOUT
1011 Set the timeout value (in seconds) until a reboot occurs when
1012 the kernel panics. If n = 0, then we wait forever. A timeout
1013 value n > 0 will wait n seconds before rebooting, while a timeout
1014 value n < 0 will reboot immediately.
1016 config LOCKUP_DETECTOR
1019 config SOFTLOCKUP_DETECTOR
1020 bool "Detect Soft Lockups"
1021 depends on DEBUG_KERNEL && !S390
1022 select LOCKUP_DETECTOR
1024 Say Y here to enable the kernel to act as a watchdog to detect
1027 Softlockups are bugs that cause the kernel to loop in kernel
1028 mode for more than 20 seconds, without giving other tasks a
1029 chance to run. The current stack trace is displayed upon
1030 detection and the system will stay locked up.
1032 config BOOTPARAM_SOFTLOCKUP_PANIC
1033 bool "Panic (Reboot) On Soft Lockups"
1034 depends on SOFTLOCKUP_DETECTOR
1036 Say Y here to enable the kernel to panic on "soft lockups",
1037 which are bugs that cause the kernel to loop in kernel
1038 mode for more than 20 seconds (configurable using the watchdog_thresh
1039 sysctl), without giving other tasks a chance to run.
1041 The panic can be used in combination with panic_timeout,
1042 to cause the system to reboot automatically after a
1043 lockup has been detected. This feature is useful for
1044 high-availability systems that have uptime guarantees and
1045 where a lockup must be resolved ASAP.
1049 config HARDLOCKUP_DETECTOR_PERF
1051 select SOFTLOCKUP_DETECTOR
1054 # Enables a timestamp based low pass filter to compensate for perf based
1055 # hard lockup detection which runs too fast due to turbo modes.
1057 config HARDLOCKUP_CHECK_TIMESTAMP
1061 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1062 # lockup detector rather than the perf based detector.
1064 config HARDLOCKUP_DETECTOR
1065 bool "Detect Hard Lockups"
1066 depends on DEBUG_KERNEL && !S390
1067 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1068 select LOCKUP_DETECTOR
1069 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1071 Say Y here to enable the kernel to act as a watchdog to detect
1074 Hardlockups are bugs that cause the CPU to loop in kernel mode
1075 for more than 10 seconds, without letting other interrupts have a
1076 chance to run. The current stack trace is displayed upon detection
1077 and the system will stay locked up.
1079 config BOOTPARAM_HARDLOCKUP_PANIC
1080 bool "Panic (Reboot) On Hard Lockups"
1081 depends on HARDLOCKUP_DETECTOR
1083 Say Y here to enable the kernel to panic on "hard lockups",
1084 which are bugs that cause the kernel to loop in kernel
1085 mode with interrupts disabled for more than 10 seconds (configurable
1086 using the watchdog_thresh sysctl).
1090 config DETECT_HUNG_TASK
1091 bool "Detect Hung Tasks"
1092 depends on DEBUG_KERNEL
1093 default SOFTLOCKUP_DETECTOR
1095 Say Y here to enable the kernel to detect "hung tasks",
1096 which are bugs that cause the task to be stuck in
1097 uninterruptible "D" state indefinitely.
1099 When a hung task is detected, the kernel will print the
1100 current stack trace (which you should report), but the
1101 task will stay in uninterruptible state. If lockdep is
1102 enabled then all held locks will also be reported. This
1103 feature has negligible overhead.
1105 config DEFAULT_HUNG_TASK_TIMEOUT
1106 int "Default timeout for hung task detection (in seconds)"
1107 depends on DETECT_HUNG_TASK
1110 This option controls the default timeout (in seconds) used
1111 to determine when a task has become non-responsive and should
1114 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1115 sysctl or by writing a value to
1116 /proc/sys/kernel/hung_task_timeout_secs.
1118 A timeout of 0 disables the check. The default is two minutes.
1119 Keeping the default should be fine in most cases.
1121 config BOOTPARAM_HUNG_TASK_PANIC
1122 bool "Panic (Reboot) On Hung Tasks"
1123 depends on DETECT_HUNG_TASK
1125 Say Y here to enable the kernel to panic on "hung tasks",
1126 which are bugs that cause the kernel to leave a task stuck
1127 in uninterruptible "D" state.
1129 The panic can be used in combination with panic_timeout,
1130 to cause the system to reboot automatically after a
1131 hung task has been detected. This feature is useful for
1132 high-availability systems that have uptime guarantees and
1133 where a hung tasks must be resolved ASAP.
1138 bool "Detect Workqueue Stalls"
1139 depends on DEBUG_KERNEL
1141 Say Y here to enable stall detection on workqueues. If a
1142 worker pool doesn't make forward progress on a pending work
1143 item for over a given amount of time, 30s by default, a
1144 warning message is printed along with dump of workqueue
1145 state. This can be configured through kernel parameter
1146 "workqueue.watchdog_thresh" and its sysfs counterpart.
1149 tristate "Test module to generate lockups"
1152 This builds the "test_lockup" module that helps to make sure
1153 that watchdogs and lockup detectors are working properly.
1155 Depending on module parameters it could emulate soft or hard
1156 lockup, "hung task", or locking arbitrary lock for a long time.
1157 Also it could generate series of lockups with cooling-down periods.
1161 endmenu # "Debug lockups and hangs"
1163 menu "Scheduler Debugging"
1166 bool "Collect scheduler debugging info"
1167 depends on DEBUG_KERNEL && PROC_FS
1170 If you say Y here, the /proc/sched_debug file will be provided
1171 that can help debug the scheduler. The runtime overhead of this
1179 bool "Collect scheduler statistics"
1180 depends on DEBUG_KERNEL && PROC_FS
1183 If you say Y here, additional code will be inserted into the
1184 scheduler and related routines to collect statistics about
1185 scheduler behavior and provide them in /proc/schedstat. These
1186 stats may be useful for both tuning and debugging the scheduler
1187 If you aren't debugging the scheduler or trying to tune a specific
1188 application, you can say N to avoid the very slight overhead
1193 config DEBUG_TIMEKEEPING
1194 bool "Enable extra timekeeping sanity checking"
1196 This option will enable additional timekeeping sanity checks
1197 which may be helpful when diagnosing issues where timekeeping
1198 problems are suspected.
1200 This may include checks in the timekeeping hotpaths, so this
1201 option may have a (very small) performance impact to some
1206 config DEBUG_PREEMPT
1207 bool "Debug preemptible kernel"
1208 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1211 If you say Y here then the kernel will use a debug variant of the
1212 commonly used smp_processor_id() function and will print warnings
1213 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1214 will detect preemption count underflows.
1216 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1218 config LOCK_DEBUGGING_SUPPORT
1220 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1223 config PROVE_LOCKING
1224 bool "Lock debugging: prove locking correctness"
1225 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1227 select DEBUG_SPINLOCK
1228 select DEBUG_MUTEXES if !PREEMPT_RT
1229 select DEBUG_RT_MUTEXES if RT_MUTEXES
1231 select DEBUG_WW_MUTEX_SLOWPATH
1232 select DEBUG_LOCK_ALLOC
1233 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1234 select TRACE_IRQFLAGS
1237 This feature enables the kernel to prove that all locking
1238 that occurs in the kernel runtime is mathematically
1239 correct: that under no circumstance could an arbitrary (and
1240 not yet triggered) combination of observed locking
1241 sequences (on an arbitrary number of CPUs, running an
1242 arbitrary number of tasks and interrupt contexts) cause a
1245 In short, this feature enables the kernel to report locking
1246 related deadlocks before they actually occur.
1248 The proof does not depend on how hard and complex a
1249 deadlock scenario would be to trigger: how many
1250 participant CPUs, tasks and irq-contexts would be needed
1251 for it to trigger. The proof also does not depend on
1252 timing: if a race and a resulting deadlock is possible
1253 theoretically (no matter how unlikely the race scenario
1254 is), it will be proven so and will immediately be
1255 reported by the kernel (once the event is observed that
1256 makes the deadlock theoretically possible).
1258 If a deadlock is impossible (i.e. the locking rules, as
1259 observed by the kernel, are mathematically correct), the
1260 kernel reports nothing.
1262 NOTE: this feature can also be enabled for rwlocks, mutexes
1263 and rwsems - in which case all dependencies between these
1264 different locking variants are observed and mapped too, and
1265 the proof of observed correctness is also maintained for an
1266 arbitrary combination of these separate locking variants.
1268 For more details, see Documentation/locking/lockdep-design.rst.
1270 config PROVE_RAW_LOCK_NESTING
1271 bool "Enable raw_spinlock - spinlock nesting checks"
1272 depends on PROVE_LOCKING
1275 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1276 that the lock nesting rules for PREEMPT_RT enabled kernels are
1279 NOTE: There are known nesting problems. So if you enable this
1280 option expect lockdep splats until these problems have been fully
1281 addressed which is work in progress. This config switch allows to
1282 identify and analyze these problems. It will be removed and the
1283 check permanently enabled once the main issues have been fixed.
1285 If unsure, select N.
1288 bool "Lock usage statistics"
1289 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1291 select DEBUG_SPINLOCK
1292 select DEBUG_MUTEXES if !PREEMPT_RT
1293 select DEBUG_RT_MUTEXES if RT_MUTEXES
1294 select DEBUG_LOCK_ALLOC
1297 This feature enables tracking lock contention points
1299 For more details, see Documentation/locking/lockstat.rst
1301 This also enables lock events required by "perf lock",
1303 If you want to use "perf lock", you also need to turn on
1304 CONFIG_EVENT_TRACING.
1306 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1307 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1309 config DEBUG_RT_MUTEXES
1310 bool "RT Mutex debugging, deadlock detection"
1311 depends on DEBUG_KERNEL && RT_MUTEXES
1313 This allows rt mutex semantics violations and rt mutex related
1314 deadlocks (lockups) to be detected and reported automatically.
1316 config DEBUG_SPINLOCK
1317 bool "Spinlock and rw-lock debugging: basic checks"
1318 depends on DEBUG_KERNEL
1319 select UNINLINE_SPIN_UNLOCK
1321 Say Y here and build SMP to catch missing spinlock initialization
1322 and certain other kinds of spinlock errors commonly made. This is
1323 best used in conjunction with the NMI watchdog so that spinlock
1324 deadlocks are also debuggable.
1326 config DEBUG_MUTEXES
1327 bool "Mutex debugging: basic checks"
1328 depends on DEBUG_KERNEL && !PREEMPT_RT
1330 This feature allows mutex semantics violations to be detected and
1333 config DEBUG_WW_MUTEX_SLOWPATH
1334 bool "Wait/wound mutex debugging: Slowpath testing"
1335 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1336 select DEBUG_LOCK_ALLOC
1337 select DEBUG_SPINLOCK
1338 select DEBUG_MUTEXES if !PREEMPT_RT
1339 select DEBUG_RT_MUTEXES if PREEMPT_RT
1341 This feature enables slowpath testing for w/w mutex users by
1342 injecting additional -EDEADLK wound/backoff cases. Together with
1343 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1344 will test all possible w/w mutex interface abuse with the
1345 exception of simply not acquiring all the required locks.
1346 Note that this feature can introduce significant overhead, so
1347 it really should not be enabled in a production or distro kernel,
1348 even a debug kernel. If you are a driver writer, enable it. If
1349 you are a distro, do not.
1352 bool "RW Semaphore debugging: basic checks"
1353 depends on DEBUG_KERNEL
1355 This debugging feature allows mismatched rw semaphore locks
1356 and unlocks to be detected and reported.
1358 config DEBUG_LOCK_ALLOC
1359 bool "Lock debugging: detect incorrect freeing of live locks"
1360 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1361 select DEBUG_SPINLOCK
1362 select DEBUG_MUTEXES if !PREEMPT_RT
1363 select DEBUG_RT_MUTEXES if RT_MUTEXES
1366 This feature will check whether any held lock (spinlock, rwlock,
1367 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1368 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1369 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1370 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1371 held during task exit.
1375 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1380 config LOCKDEP_SMALL
1384 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1385 depends on LOCKDEP && !LOCKDEP_SMALL
1389 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1391 config LOCKDEP_CHAINS_BITS
1392 int "Bitsize for MAX_LOCKDEP_CHAINS"
1393 depends on LOCKDEP && !LOCKDEP_SMALL
1397 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1399 config LOCKDEP_STACK_TRACE_BITS
1400 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1401 depends on LOCKDEP && !LOCKDEP_SMALL
1405 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1407 config LOCKDEP_STACK_TRACE_HASH_BITS
1408 int "Bitsize for STACK_TRACE_HASH_SIZE"
1409 depends on LOCKDEP && !LOCKDEP_SMALL
1413 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1415 config LOCKDEP_CIRCULAR_QUEUE_BITS
1416 int "Bitsize for elements in circular_queue struct"
1421 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1423 config DEBUG_LOCKDEP
1424 bool "Lock dependency engine debugging"
1425 depends on DEBUG_KERNEL && LOCKDEP
1426 select DEBUG_IRQFLAGS
1428 If you say Y here, the lock dependency engine will do
1429 additional runtime checks to debug itself, at the price
1430 of more runtime overhead.
1432 config DEBUG_ATOMIC_SLEEP
1433 bool "Sleep inside atomic section checking"
1434 select PREEMPT_COUNT
1435 depends on DEBUG_KERNEL
1436 depends on !ARCH_NO_PREEMPT
1438 If you say Y here, various routines which may sleep will become very
1439 noisy if they are called inside atomic sections: when a spinlock is
1440 held, inside an rcu read side critical section, inside preempt disabled
1441 sections, inside an interrupt, etc...
1443 config DEBUG_LOCKING_API_SELFTESTS
1444 bool "Locking API boot-time self-tests"
1445 depends on DEBUG_KERNEL
1447 Say Y here if you want the kernel to run a short self-test during
1448 bootup. The self-test checks whether common types of locking bugs
1449 are detected by debugging mechanisms or not. (if you disable
1450 lock debugging then those bugs won't be detected of course.)
1451 The following locking APIs are covered: spinlocks, rwlocks,
1454 config LOCK_TORTURE_TEST
1455 tristate "torture tests for locking"
1456 depends on DEBUG_KERNEL
1459 This option provides a kernel module that runs torture tests
1460 on kernel locking primitives. The kernel module may be built
1461 after the fact on the running kernel to be tested, if desired.
1463 Say Y here if you want kernel locking-primitive torture tests
1464 to be built into the kernel.
1465 Say M if you want these torture tests to build as a module.
1466 Say N if you are unsure.
1468 config WW_MUTEX_SELFTEST
1469 tristate "Wait/wound mutex selftests"
1471 This option provides a kernel module that runs tests on the
1472 on the struct ww_mutex locking API.
1474 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1475 with this test harness.
1477 Say M if you want these self tests to build as a module.
1478 Say N if you are unsure.
1480 config SCF_TORTURE_TEST
1481 tristate "torture tests for smp_call_function*()"
1482 depends on DEBUG_KERNEL
1485 This option provides a kernel module that runs torture tests
1486 on the smp_call_function() family of primitives. The kernel
1487 module may be built after the fact on the running kernel to
1488 be tested, if desired.
1490 config CSD_LOCK_WAIT_DEBUG
1491 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1492 depends on DEBUG_KERNEL
1496 This option enables debug prints when CPUs are slow to respond
1497 to the smp_call_function*() IPI wrappers. These debug prints
1498 include the IPI handler function currently executing (if any)
1499 and relevant stack traces.
1501 endmenu # lock debugging
1503 config TRACE_IRQFLAGS
1504 depends on TRACE_IRQFLAGS_SUPPORT
1507 Enables hooks to interrupt enabling and disabling for
1508 either tracing or lock debugging.
1510 config TRACE_IRQFLAGS_NMI
1512 depends on TRACE_IRQFLAGS
1513 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1515 config DEBUG_IRQFLAGS
1516 bool "Debug IRQ flag manipulation"
1518 Enables checks for potentially unsafe enabling or disabling of
1519 interrupts, such as calling raw_local_irq_restore() when interrupts
1523 bool "Stack backtrace support"
1524 depends on STACKTRACE_SUPPORT
1526 This option causes the kernel to create a /proc/pid/stack for
1527 every process, showing its current stack trace.
1528 It is also used by various kernel debugging features that require
1529 stack trace generation.
1531 config WARN_ALL_UNSEEDED_RANDOM
1532 bool "Warn for all uses of unseeded randomness"
1535 Some parts of the kernel contain bugs relating to their use of
1536 cryptographically secure random numbers before it's actually possible
1537 to generate those numbers securely. This setting ensures that these
1538 flaws don't go unnoticed, by enabling a message, should this ever
1539 occur. This will allow people with obscure setups to know when things
1540 are going wrong, so that they might contact developers about fixing
1543 Unfortunately, on some models of some architectures getting
1544 a fully seeded CRNG is extremely difficult, and so this can
1545 result in dmesg getting spammed for a surprisingly long
1546 time. This is really bad from a security perspective, and
1547 so architecture maintainers really need to do what they can
1548 to get the CRNG seeded sooner after the system is booted.
1549 However, since users cannot do anything actionable to
1550 address this, by default this option is disabled.
1552 Say Y here if you want to receive warnings for all uses of
1553 unseeded randomness. This will be of use primarily for
1554 those developers interested in improving the security of
1555 Linux kernels running on their architecture (or
1558 config DEBUG_KOBJECT
1559 bool "kobject debugging"
1560 depends on DEBUG_KERNEL
1562 If you say Y here, some extra kobject debugging messages will be sent
1565 config DEBUG_KOBJECT_RELEASE
1566 bool "kobject release debugging"
1567 depends on DEBUG_OBJECTS_TIMERS
1569 kobjects are reference counted objects. This means that their
1570 last reference count put is not predictable, and the kobject can
1571 live on past the point at which a driver decides to drop its
1572 initial reference to the kobject gained on allocation. An
1573 example of this would be a struct device which has just been
1576 However, some buggy drivers assume that after such an operation,
1577 the memory backing the kobject can be immediately freed. This
1578 goes completely against the principles of a refcounted object.
1580 If you say Y here, the kernel will delay the release of kobjects
1581 on the last reference count to improve the visibility of this
1582 kind of kobject release bug.
1584 config HAVE_DEBUG_BUGVERBOSE
1587 menu "Debug kernel data structures"
1590 bool "Debug linked list manipulation"
1591 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1593 Enable this to turn on extended checks in the linked-list
1599 bool "Debug priority linked list manipulation"
1600 depends on DEBUG_KERNEL
1602 Enable this to turn on extended checks in the priority-ordered
1603 linked-list (plist) walking routines. This checks the entire
1604 list multiple times during each manipulation.
1609 bool "Debug SG table operations"
1610 depends on DEBUG_KERNEL
1612 Enable this to turn on checks on scatter-gather tables. This can
1613 help find problems with drivers that do not properly initialize
1618 config DEBUG_NOTIFIERS
1619 bool "Debug notifier call chains"
1620 depends on DEBUG_KERNEL
1622 Enable this to turn on sanity checking for notifier call chains.
1623 This is most useful for kernel developers to make sure that
1624 modules properly unregister themselves from notifier chains.
1625 This is a relatively cheap check but if you care about maximum
1628 config BUG_ON_DATA_CORRUPTION
1629 bool "Trigger a BUG when data corruption is detected"
1632 Select this option if the kernel should BUG when it encounters
1633 data corruption in kernel memory structures when they get checked
1640 config DEBUG_CREDENTIALS
1641 bool "Debug credential management"
1642 depends on DEBUG_KERNEL
1644 Enable this to turn on some debug checking for credential
1645 management. The additional code keeps track of the number of
1646 pointers from task_structs to any given cred struct, and checks to
1647 see that this number never exceeds the usage count of the cred
1650 Furthermore, if SELinux is enabled, this also checks that the
1651 security pointer in the cred struct is never seen to be invalid.
1655 source "kernel/rcu/Kconfig.debug"
1657 config DEBUG_WQ_FORCE_RR_CPU
1658 bool "Force round-robin CPU selection for unbound work items"
1659 depends on DEBUG_KERNEL
1662 Workqueue used to implicitly guarantee that work items queued
1663 without explicit CPU specified are put on the local CPU. This
1664 guarantee is no longer true and while local CPU is still
1665 preferred work items may be put on foreign CPUs. Kernel
1666 parameter "workqueue.debug_force_rr_cpu" is added to force
1667 round-robin CPU selection to flush out usages which depend on the
1668 now broken guarantee. This config option enables the debug
1669 feature by default. When enabled, memory and cache locality will
1672 config CPU_HOTPLUG_STATE_CONTROL
1673 bool "Enable CPU hotplug state control"
1674 depends on DEBUG_KERNEL
1675 depends on HOTPLUG_CPU
1678 Allows to write steps between "offline" and "online" to the CPUs
1679 sysfs target file so states can be stepped granular. This is a debug
1680 option for now as the hotplug machinery cannot be stopped and
1681 restarted at arbitrary points yet.
1683 Say N if your are unsure.
1686 bool "Latency measuring infrastructure"
1687 depends on DEBUG_KERNEL
1688 depends on STACKTRACE_SUPPORT
1690 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1696 Enable this option if you want to use the LatencyTOP tool
1697 to find out which userspace is blocking on what kernel operations.
1699 source "kernel/trace/Kconfig"
1701 config PROVIDE_OHCI1394_DMA_INIT
1702 bool "Remote debugging over FireWire early on boot"
1703 depends on PCI && X86
1705 If you want to debug problems which hang or crash the kernel early
1706 on boot and the crashing machine has a FireWire port, you can use
1707 this feature to remotely access the memory of the crashed machine
1708 over FireWire. This employs remote DMA as part of the OHCI1394
1709 specification which is now the standard for FireWire controllers.
1711 With remote DMA, you can monitor the printk buffer remotely using
1712 firescope and access all memory below 4GB using fireproxy from gdb.
1713 Even controlling a kernel debugger is possible using remote DMA.
1717 If ohci1394_dma=early is used as boot parameter, it will initialize
1718 all OHCI1394 controllers which are found in the PCI config space.
1720 As all changes to the FireWire bus such as enabling and disabling
1721 devices cause a bus reset and thereby disable remote DMA for all
1722 devices, be sure to have the cable plugged and FireWire enabled on
1723 the debugging host before booting the debug target for debugging.
1725 This code (~1k) is freed after boot. By then, the firewire stack
1726 in charge of the OHCI-1394 controllers should be used instead.
1728 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1730 source "samples/Kconfig"
1732 config ARCH_HAS_DEVMEM_IS_ALLOWED
1735 config STRICT_DEVMEM
1736 bool "Filter access to /dev/mem"
1737 depends on MMU && DEVMEM
1738 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1739 default y if PPC || X86 || ARM64
1741 If this option is disabled, you allow userspace (root) access to all
1742 of memory, including kernel and userspace memory. Accidental
1743 access to this is obviously disastrous, but specific access can
1744 be used by people debugging the kernel. Note that with PAT support
1745 enabled, even in this case there are restrictions on /dev/mem
1746 use due to the cache aliasing requirements.
1748 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1749 file only allows userspace access to PCI space and the BIOS code and
1750 data regions. This is sufficient for dosemu and X and all common
1755 config IO_STRICT_DEVMEM
1756 bool "Filter I/O access to /dev/mem"
1757 depends on STRICT_DEVMEM
1759 If this option is disabled, you allow userspace (root) access to all
1760 io-memory regardless of whether a driver is actively using that
1761 range. Accidental access to this is obviously disastrous, but
1762 specific access can be used by people debugging kernel drivers.
1764 If this option is switched on, the /dev/mem file only allows
1765 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1766 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1767 if the driver using a given range cannot be disabled.
1771 menu "$(SRCARCH) Debugging"
1773 source "arch/$(SRCARCH)/Kconfig.debug"
1777 menu "Kernel Testing and Coverage"
1779 source "lib/kunit/Kconfig"
1781 config NOTIFIER_ERROR_INJECTION
1782 tristate "Notifier error injection"
1783 depends on DEBUG_KERNEL
1786 This option provides the ability to inject artificial errors to
1787 specified notifier chain callbacks. It is useful to test the error
1788 handling of notifier call chain failures.
1792 config PM_NOTIFIER_ERROR_INJECT
1793 tristate "PM notifier error injection module"
1794 depends on PM && NOTIFIER_ERROR_INJECTION
1795 default m if PM_DEBUG
1797 This option provides the ability to inject artificial errors to
1798 PM notifier chain callbacks. It is controlled through debugfs
1799 interface /sys/kernel/debug/notifier-error-inject/pm
1801 If the notifier call chain should be failed with some events
1802 notified, write the error code to "actions/<notifier event>/error".
1804 Example: Inject PM suspend error (-12 = -ENOMEM)
1806 # cd /sys/kernel/debug/notifier-error-inject/pm/
1807 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1808 # echo mem > /sys/power/state
1809 bash: echo: write error: Cannot allocate memory
1811 To compile this code as a module, choose M here: the module will
1812 be called pm-notifier-error-inject.
1816 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1817 tristate "OF reconfig notifier error injection module"
1818 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1820 This option provides the ability to inject artificial errors to
1821 OF reconfig notifier chain callbacks. It is controlled
1822 through debugfs interface under
1823 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1825 If the notifier call chain should be failed with some events
1826 notified, write the error code to "actions/<notifier event>/error".
1828 To compile this code as a module, choose M here: the module will
1829 be called of-reconfig-notifier-error-inject.
1833 config NETDEV_NOTIFIER_ERROR_INJECT
1834 tristate "Netdev notifier error injection module"
1835 depends on NET && NOTIFIER_ERROR_INJECTION
1837 This option provides the ability to inject artificial errors to
1838 netdevice notifier chain callbacks. It is controlled through debugfs
1839 interface /sys/kernel/debug/notifier-error-inject/netdev
1841 If the notifier call chain should be failed with some events
1842 notified, write the error code to "actions/<notifier event>/error".
1844 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1846 # cd /sys/kernel/debug/notifier-error-inject/netdev
1847 # echo -22 > actions/NETDEV_CHANGEMTU/error
1848 # ip link set eth0 mtu 1024
1849 RTNETLINK answers: Invalid argument
1851 To compile this code as a module, choose M here: the module will
1852 be called netdev-notifier-error-inject.
1856 config FUNCTION_ERROR_INJECTION
1858 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1860 config FAULT_INJECTION
1861 bool "Fault-injection framework"
1862 depends on DEBUG_KERNEL
1864 Provide fault-injection framework.
1865 For more details, see Documentation/fault-injection/.
1868 bool "Fault-injection capability for kmalloc"
1869 depends on FAULT_INJECTION
1870 depends on SLAB || SLUB
1872 Provide fault-injection capability for kmalloc.
1874 config FAIL_PAGE_ALLOC
1875 bool "Fault-injection capability for alloc_pages()"
1876 depends on FAULT_INJECTION
1878 Provide fault-injection capability for alloc_pages().
1880 config FAULT_INJECTION_USERCOPY
1881 bool "Fault injection capability for usercopy functions"
1882 depends on FAULT_INJECTION
1884 Provides fault-injection capability to inject failures
1885 in usercopy functions (copy_from_user(), get_user(), ...).
1887 config FAIL_MAKE_REQUEST
1888 bool "Fault-injection capability for disk IO"
1889 depends on FAULT_INJECTION && BLOCK
1891 Provide fault-injection capability for disk IO.
1893 config FAIL_IO_TIMEOUT
1894 bool "Fault-injection capability for faking disk interrupts"
1895 depends on FAULT_INJECTION && BLOCK
1897 Provide fault-injection capability on end IO handling. This
1898 will make the block layer "forget" an interrupt as configured,
1899 thus exercising the error handling.
1901 Only works with drivers that use the generic timeout handling,
1902 for others it won't do anything.
1905 bool "Fault-injection capability for futexes"
1907 depends on FAULT_INJECTION && FUTEX
1909 Provide fault-injection capability for futexes.
1911 config FAULT_INJECTION_DEBUG_FS
1912 bool "Debugfs entries for fault-injection capabilities"
1913 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1915 Enable configuration of fault-injection capabilities via debugfs.
1917 config FAIL_FUNCTION
1918 bool "Fault-injection capability for functions"
1919 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1921 Provide function-based fault-injection capability.
1922 This will allow you to override a specific function with a return
1923 with given return value. As a result, function caller will see
1924 an error value and have to handle it. This is useful to test the
1925 error handling in various subsystems.
1927 config FAIL_MMC_REQUEST
1928 bool "Fault-injection capability for MMC IO"
1929 depends on FAULT_INJECTION_DEBUG_FS && MMC
1931 Provide fault-injection capability for MMC IO.
1932 This will make the mmc core return data errors. This is
1933 useful to test the error handling in the mmc block device
1934 and to test how the mmc host driver handles retries from
1938 bool "Fault-injection capability for SunRPC"
1939 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1941 Provide fault-injection capability for SunRPC and
1944 config FAULT_INJECTION_STACKTRACE_FILTER
1945 bool "stacktrace filter for fault-injection capabilities"
1946 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1949 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1951 Provide stacktrace filter for fault-injection capabilities
1953 config ARCH_HAS_KCOV
1956 An architecture should select this when it can successfully
1957 build and run with CONFIG_KCOV. This typically requires
1958 disabling instrumentation for some early boot code.
1960 config CC_HAS_SANCOV_TRACE_PC
1961 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1965 bool "Code coverage for fuzzing"
1966 depends on ARCH_HAS_KCOV
1967 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1968 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
1969 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
1971 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1972 select OBJTOOL if HAVE_NOINSTR_HACK
1974 KCOV exposes kernel code coverage information in a form suitable
1975 for coverage-guided fuzzing (randomized testing).
1977 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1978 different machines and across reboots. If you need stable PC values,
1979 disable RANDOMIZE_BASE.
1981 For more details, see Documentation/dev-tools/kcov.rst.
1983 config KCOV_ENABLE_COMPARISONS
1984 bool "Enable comparison operands collection by KCOV"
1986 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
1988 KCOV also exposes operands of every comparison in the instrumented
1989 code along with operand sizes and PCs of the comparison instructions.
1990 These operands can be used by fuzzing engines to improve the quality
1991 of fuzzing coverage.
1993 config KCOV_INSTRUMENT_ALL
1994 bool "Instrument all code by default"
1998 If you are doing generic system call fuzzing (like e.g. syzkaller),
1999 then you will want to instrument the whole kernel and you should
2000 say y here. If you are doing more targeted fuzzing (like e.g.
2001 filesystem fuzzing with AFL) then you will want to enable coverage
2002 for more specific subsets of files, and should say n here.
2004 config KCOV_IRQ_AREA_SIZE
2005 hex "Size of interrupt coverage collection area in words"
2009 KCOV uses preallocated per-cpu areas to collect coverage from
2010 soft interrupts. This specifies the size of those areas in the
2011 number of unsigned long words.
2013 menuconfig RUNTIME_TESTING_MENU
2014 bool "Runtime Testing"
2017 if RUNTIME_TESTING_MENU
2020 tristate "Linux Kernel Dump Test Tool Module"
2023 This module enables testing of the different dumping mechanisms by
2024 inducing system failures at predefined crash points.
2025 If you don't need it: say N
2026 Choose M here to compile this code as a module. The module will be
2029 Documentation on how to use the module can be found in
2030 Documentation/fault-injection/provoke-crashes.rst
2032 config CPUMASK_KUNIT_TEST
2033 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2035 default KUNIT_ALL_TESTS
2037 Enable to turn on cpumask tests, running at boot or module load time.
2039 For more information on KUnit and unit tests in general, please refer
2040 to the KUnit documentation in Documentation/dev-tools/kunit/.
2044 config TEST_LIST_SORT
2045 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2047 default KUNIT_ALL_TESTS
2049 Enable this to turn on 'list_sort()' function test. This test is
2050 executed only once during system boot (so affects only boot time),
2051 or at module load time.
2055 config TEST_MIN_HEAP
2056 tristate "Min heap test"
2057 depends on DEBUG_KERNEL || m
2059 Enable this to turn on min heap function tests. This test is
2060 executed only once during system boot (so affects only boot time),
2061 or at module load time.
2066 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2068 default KUNIT_ALL_TESTS
2070 This option enables the self-test function of 'sort()' at boot,
2071 or at module load time.
2076 tristate "64bit/32bit division and modulo test"
2077 depends on DEBUG_KERNEL || m
2079 Enable this to turn on 'do_div()' function test. This test is
2080 executed only once during system boot (so affects only boot time),
2081 or at module load time.
2085 config KPROBES_SANITY_TEST
2086 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2087 depends on DEBUG_KERNEL
2090 default KUNIT_ALL_TESTS
2092 This option provides for testing basic kprobes functionality on
2093 boot. Samples of kprobe and kretprobe are inserted and
2094 verified for functionality.
2096 Say N if you are unsure.
2098 config FPROBE_SANITY_TEST
2099 bool "Self test for fprobe"
2100 depends on DEBUG_KERNEL
2104 This option will enable testing the fprobe when the system boot.
2105 A series of tests are made to verify that the fprobe is functioning
2108 Say N if you are unsure.
2110 config BACKTRACE_SELF_TEST
2111 tristate "Self test for the backtrace code"
2112 depends on DEBUG_KERNEL
2114 This option provides a kernel module that can be used to test
2115 the kernel stack backtrace code. This option is not useful
2116 for distributions or general kernels, but only for kernel
2117 developers working on architecture code.
2119 Note that if you want to also test saved backtraces, you will
2120 have to enable STACKTRACE as well.
2122 Say N if you are unsure.
2124 config TEST_REF_TRACKER
2125 tristate "Self test for reference tracker"
2126 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2129 This option provides a kernel module performing tests
2130 using reference tracker infrastructure.
2132 Say N if you are unsure.
2135 tristate "Red-Black tree test"
2136 depends on DEBUG_KERNEL
2138 A benchmark measuring the performance of the rbtree library.
2139 Also includes rbtree invariant checks.
2141 config REED_SOLOMON_TEST
2142 tristate "Reed-Solomon library test"
2143 depends on DEBUG_KERNEL || m
2145 select REED_SOLOMON_ENC16
2146 select REED_SOLOMON_DEC16
2148 This option enables the self-test function of rslib at boot,
2149 or at module load time.
2153 config INTERVAL_TREE_TEST
2154 tristate "Interval tree test"
2155 depends on DEBUG_KERNEL
2156 select INTERVAL_TREE
2158 A benchmark measuring the performance of the interval tree library
2161 tristate "Per cpu operations test"
2162 depends on m && DEBUG_KERNEL
2164 Enable this option to build test module which validates per-cpu
2169 config ATOMIC64_SELFTEST
2170 tristate "Perform an atomic64_t self-test"
2172 Enable this option to test the atomic64_t functions at boot or
2173 at module load time.
2177 config ASYNC_RAID6_TEST
2178 tristate "Self test for hardware accelerated raid6 recovery"
2179 depends on ASYNC_RAID6_RECOV
2182 This is a one-shot self test that permutes through the
2183 recovery of all the possible two disk failure scenarios for a
2184 N-disk array. Recovery is performed with the asynchronous
2185 raid6 recovery routines, and will optionally use an offload
2186 engine if one is available.
2191 tristate "Test functions located in the hexdump module at runtime"
2193 config STRING_SELFTEST
2194 tristate "Test string functions at runtime"
2196 config TEST_STRING_HELPERS
2197 tristate "Test functions located in the string_helpers module at runtime"
2200 tristate "Test strscpy*() family of functions at runtime"
2203 tristate "Test kstrto*() family of functions at runtime"
2206 tristate "Test printf() family of functions at runtime"
2209 tristate "Test scanf() family of functions at runtime"
2212 tristate "Test bitmap_*() family of functions at runtime"
2214 Enable this option to test the bitmap functions at boot.
2219 tristate "Test functions located in the uuid module at runtime"
2222 tristate "Test the XArray code at runtime"
2224 config TEST_RHASHTABLE
2225 tristate "Perform selftest on resizable hash table"
2227 Enable this option to test the rhashtable functions at boot.
2232 tristate "Perform selftest on siphash functions"
2234 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2235 functions on boot (or module load).
2237 This is intended to help people writing architecture-specific
2238 optimized versions. If unsure, say N.
2241 tristate "Perform selftest on IDA functions"
2244 tristate "Perform selftest on priority array manager"
2247 Enable this option to test priority array manager on boot
2252 config TEST_IRQ_TIMINGS
2253 bool "IRQ timings selftest"
2254 depends on IRQ_TIMINGS
2256 Enable this option to test the irq timings code on boot.
2261 tristate "Test module loading with 'hello world' module"
2264 This builds the "test_module" module that emits "Hello, world"
2265 on printk when loaded. It is designed to be used for basic
2266 evaluation of the module loading subsystem (for example when
2267 validating module verification). It lacks any extra dependencies,
2268 and will not normally be loaded by the system unless explicitly
2274 tristate "Test module for compilation of bitops operations"
2277 This builds the "test_bitops" module that is much like the
2278 TEST_LKM module except that it does a basic exercise of the
2279 set/clear_bit macros and get_count_order/long to make sure there are
2280 no compiler warnings from C=1 sparse checker or -Wextra
2281 compilations. It has no dependencies and doesn't run or load unless
2282 explicitly requested by name. for example: modprobe test_bitops.
2287 tristate "Test module for stress/performance analysis of vmalloc allocator"
2292 This builds the "test_vmalloc" module that should be used for
2293 stress and performance analysis. So, any new change for vmalloc
2294 subsystem can be evaluated from performance and stability point
2299 config TEST_USER_COPY
2300 tristate "Test user/kernel boundary protections"
2303 This builds the "test_user_copy" module that runs sanity checks
2304 on the copy_to/from_user infrastructure, making sure basic
2305 user/kernel boundary testing is working. If it fails to load,
2306 a regression has been detected in the user/kernel memory boundary
2312 tristate "Test BPF filter functionality"
2315 This builds the "test_bpf" module that runs various test vectors
2316 against the BPF interpreter or BPF JIT compiler depending on the
2317 current setting. This is in particular useful for BPF JIT compiler
2318 development, but also to run regression tests against changes in
2319 the interpreter code. It also enables test stubs for eBPF maps and
2320 verifier used by user space verifier testsuite.
2324 config TEST_BLACKHOLE_DEV
2325 tristate "Test blackhole netdev functionality"
2328 This builds the "test_blackhole_dev" module that validates the
2329 data path through this blackhole netdev.
2333 config FIND_BIT_BENCHMARK
2334 tristate "Test find_bit functions"
2336 This builds the "test_find_bit" module that measure find_*_bit()
2337 functions performance.
2341 config TEST_FIRMWARE
2342 tristate "Test firmware loading via userspace interface"
2343 depends on FW_LOADER
2345 This builds the "test_firmware" module that creates a userspace
2346 interface for testing firmware loading. This can be used to
2347 control the triggering of firmware loading without needing an
2348 actual firmware-using device. The contents can be rechecked by
2354 tristate "sysctl test driver"
2355 depends on PROC_SYSCTL
2357 This builds the "test_sysctl" module. This driver enables to test the
2358 proc sysctl interfaces available to drivers safely without affecting
2359 production knobs which might alter system functionality.
2363 config BITFIELD_KUNIT
2364 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2366 default KUNIT_ALL_TESTS
2368 Enable this option to test the bitfield functions at boot.
2370 KUnit tests run during boot and output the results to the debug log
2371 in TAP format (http://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/.
2380 config HASH_KUNIT_TEST
2381 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2383 default KUNIT_ALL_TESTS
2385 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2386 integer (<linux/hash.h>) hash functions on boot.
2388 KUnit tests run during boot and output the results to the debug log
2389 in TAP format (https://testanything.org/). Only useful for kernel devs
2390 running the KUnit test harness, and not intended for inclusion into a
2393 For more information on KUnit and unit tests in general please refer
2394 to the KUnit documentation in Documentation/dev-tools/kunit/.
2396 This is intended to help people writing architecture-specific
2397 optimized versions. If unsure, say N.
2399 config RESOURCE_KUNIT_TEST
2400 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2402 default KUNIT_ALL_TESTS
2404 This builds the resource API unit test.
2405 Tests the logic of API provided by resource.c and ioport.h.
2406 For more information on KUnit and unit tests in general please refer
2407 to the KUnit documentation in Documentation/dev-tools/kunit/.
2411 config SYSCTL_KUNIT_TEST
2412 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2414 default KUNIT_ALL_TESTS
2416 This builds the proc sysctl unit test, which runs on boot.
2417 Tests the API contract and implementation correctness of sysctl.
2418 For more information on KUnit and unit tests in general please refer
2419 to the KUnit documentation in Documentation/dev-tools/kunit/.
2423 config LIST_KUNIT_TEST
2424 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2426 default KUNIT_ALL_TESTS
2428 This builds the linked list KUnit test suite.
2429 It tests that the API and basic functionality of the list_head type
2430 and associated macros.
2432 KUnit tests run during boot and output the results to the debug log
2433 in TAP format (https://testanything.org/). Only useful for kernel devs
2434 running the KUnit test harness, and not intended for inclusion into a
2437 For more information on KUnit and unit tests in general please refer
2438 to the KUnit documentation in Documentation/dev-tools/kunit/.
2442 config LINEAR_RANGES_TEST
2443 tristate "KUnit test for linear_ranges"
2445 select LINEAR_RANGES
2447 This builds the linear_ranges unit test, which runs on boot.
2448 Tests the linear_ranges logic correctness.
2449 For more information on KUnit and unit tests in general please refer
2450 to the KUnit documentation in Documentation/dev-tools/kunit/.
2454 config CMDLINE_KUNIT_TEST
2455 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2457 default KUNIT_ALL_TESTS
2459 This builds the cmdline API unit test.
2460 Tests the logic of API provided by cmdline.c.
2461 For more information on KUnit and unit tests in general please refer
2462 to the KUnit documentation in Documentation/dev-tools/kunit/.
2467 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2469 default KUNIT_ALL_TESTS
2471 This builds the bits unit test.
2472 Tests the logic of macros defined in bits.h.
2473 For more information on KUnit and unit tests in general please refer
2474 to the KUnit documentation in Documentation/dev-tools/kunit/.
2478 config SLUB_KUNIT_TEST
2479 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2480 depends on SLUB_DEBUG && KUNIT
2481 default KUNIT_ALL_TESTS
2483 This builds SLUB allocator unit test.
2484 Tests SLUB cache debugging functionality.
2485 For more information on KUnit and unit tests in general please refer
2486 to the KUnit documentation in Documentation/dev-tools/kunit/.
2490 config RATIONAL_KUNIT_TEST
2491 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2492 depends on KUNIT && RATIONAL
2493 default KUNIT_ALL_TESTS
2495 This builds the rational math unit test.
2496 For more information on KUnit and unit tests in general please refer
2497 to the KUnit documentation in Documentation/dev-tools/kunit/.
2501 config MEMCPY_KUNIT_TEST
2502 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2504 default KUNIT_ALL_TESTS
2506 Builds unit tests for memcpy(), memmove(), and memset() functions.
2507 For more information on KUnit and unit tests in general please refer
2508 to the KUnit documentation in Documentation/dev-tools/kunit/.
2512 config OVERFLOW_KUNIT_TEST
2513 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2515 default KUNIT_ALL_TESTS
2517 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2520 For more information on KUnit and unit tests in general please refer
2521 to the KUnit documentation in Documentation/dev-tools/kunit/.
2525 config STACKINIT_KUNIT_TEST
2526 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2528 default KUNIT_ALL_TESTS
2530 Test if the kernel is zero-initializing stack variables and
2531 padding. Coverage is controlled by compiler flags,
2532 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2533 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2534 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2537 tristate "udelay test driver"
2539 This builds the "udelay_test" module that helps to make sure
2540 that udelay() is working properly.
2544 config TEST_STATIC_KEYS
2545 tristate "Test static keys"
2548 Test the static key interfaces.
2553 tristate "kmod stress tester"
2555 depends on NETDEVICES && NET_CORE && INET # for TUN
2557 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2563 Test the kernel's module loading mechanism: kmod. kmod implements
2564 support to load modules using the Linux kernel's usermode helper.
2565 This test provides a series of tests against kmod.
2567 Although technically you can either build test_kmod as a module or
2568 into the kernel we disallow building it into the kernel since
2569 it stress tests request_module() and this will very likely cause
2570 some issues by taking over precious threads available from other
2571 module load requests, ultimately this could be fatal.
2575 tools/testing/selftests/kmod/kmod.sh --help
2579 config TEST_DEBUG_VIRTUAL
2580 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2581 depends on DEBUG_VIRTUAL
2583 Test the kernel's ability to detect incorrect calls to
2584 virt_to_phys() done against the non-linear part of the
2585 kernel's virtual address map.
2589 config TEST_MEMCAT_P
2590 tristate "Test memcat_p() helper function"
2592 Test the memcat_p() helper for correctly merging two
2593 pointer arrays together.
2597 config TEST_LIVEPATCH
2598 tristate "Test livepatching"
2600 depends on DYNAMIC_DEBUG
2601 depends on LIVEPATCH
2604 Test kernel livepatching features for correctness. The tests will
2605 load test modules that will be livepatched in various scenarios.
2607 To run all the livepatching tests:
2609 make -C tools/testing/selftests TARGETS=livepatch run_tests
2611 Alternatively, individual tests may be invoked:
2613 tools/testing/selftests/livepatch/test-callbacks.sh
2614 tools/testing/selftests/livepatch/test-livepatch.sh
2615 tools/testing/selftests/livepatch/test-shadow-vars.sh
2620 tristate "Perform selftest on object aggreration manager"
2624 Enable this option to test object aggregation manager on boot
2628 tristate "Test heap/page initialization"
2630 Test if the kernel is zero-initializing heap and page allocations.
2631 This can be useful to test init_on_alloc and init_on_free features.
2636 tristate "Test HMM (Heterogeneous Memory Management)"
2637 depends on TRANSPARENT_HUGEPAGE
2638 depends on DEVICE_PRIVATE
2642 This is a pseudo device driver solely for testing HMM.
2643 Say M here if you want to build the HMM test module.
2644 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2648 config TEST_FREE_PAGES
2649 tristate "Test freeing pages"
2651 Test that a memory leak does not occur due to a race between
2652 freeing a block of pages and a speculative page reference.
2653 Loading this module is safe if your kernel has the bug fixed.
2654 If the bug is not fixed, it will leak gigabytes of memory and
2655 probably OOM your system.
2658 tristate "Test floating point operations in kernel space"
2659 depends on X86 && !KCOV_INSTRUMENT_ALL
2661 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2662 which will trigger a sequence of floating point operations. This is used
2663 for self-testing floating point control register setting in
2668 config TEST_CLOCKSOURCE_WATCHDOG
2669 tristate "Test clocksource watchdog in kernel space"
2670 depends on CLOCKSOURCE_WATCHDOG
2672 Enable this option to create a kernel module that will trigger
2673 a test of the clocksource watchdog. This module may be loaded
2674 via modprobe or insmod in which case it will run upon being
2675 loaded, or it may be built in, in which case it will run
2680 endif # RUNTIME_TESTING_MENU
2682 config ARCH_USE_MEMTEST
2685 An architecture should select this when it uses early_memtest()
2686 during boot process.
2690 depends on ARCH_USE_MEMTEST
2692 This option adds a kernel parameter 'memtest', which allows memtest
2693 to be set and executed.
2694 memtest=0, mean disabled; -- default
2695 memtest=1, mean do 1 test pattern;
2697 memtest=17, mean do 17 test patterns.
2698 If you are unsure how to answer this question, answer N.
2702 config HYPERV_TESTING
2703 bool "Microsoft Hyper-V driver testing"
2705 depends on HYPERV && DEBUG_FS
2707 Select this option to enable Hyper-V vmbus testing.
2709 endmenu # "Kernel Testing and Coverage"
2711 source "Documentation/Kconfig"
2713 endmenu # Kernel hacking
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