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)
488 config STACK_VALIDATION
489 bool "Compile-time stack metadata validation"
490 depends on HAVE_STACK_VALIDATION
493 Add compile-time checks to validate stack metadata, including frame
494 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
495 that runtime stack traces are more reliable.
497 This is also a prerequisite for generation of ORC unwind data, which
498 is needed for CONFIG_UNWINDER_ORC.
500 For more information, see
501 tools/objtool/Documentation/stack-validation.txt.
503 config VMLINUX_VALIDATION
505 depends on STACK_VALIDATION && DEBUG_ENTRY
509 bool "Generate vmlinux.map file when linking"
512 Selecting this option will pass "-Map=vmlinux.map" to ld
513 when linking vmlinux. That file can be useful for verifying
514 and debugging magic section games, and for seeing which
515 pieces of code get eliminated with
516 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
518 config DEBUG_FORCE_WEAK_PER_CPU
519 bool "Force weak per-cpu definitions"
520 depends on DEBUG_KERNEL
522 s390 and alpha require percpu variables in modules to be
523 defined weak to work around addressing range issue which
524 puts the following two restrictions on percpu variable
527 1. percpu symbols must be unique whether static or not
528 2. percpu variables can't be defined inside a function
530 To ensure that generic code follows the above rules, this
531 option forces all percpu variables to be defined as weak.
533 endmenu # "Compiler options"
535 menu "Generic Kernel Debugging Instruments"
538 bool "Magic SysRq key"
541 If you say Y here, you will have some control over the system even
542 if the system crashes for example during kernel debugging (e.g., you
543 will be able to flush the buffer cache to disk, reboot the system
544 immediately or dump some status information). This is accomplished
545 by pressing various keys while holding SysRq (Alt+PrintScreen). It
546 also works on a serial console (on PC hardware at least), if you
547 send a BREAK and then within 5 seconds a command keypress. The
548 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
549 Don't say Y unless you really know what this hack does.
551 config MAGIC_SYSRQ_DEFAULT_ENABLE
552 hex "Enable magic SysRq key functions by default"
553 depends on MAGIC_SYSRQ
556 Specifies which SysRq key functions are enabled by default.
557 This may be set to 1 or 0 to enable or disable them all, or
558 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
560 config MAGIC_SYSRQ_SERIAL
561 bool "Enable magic SysRq key over serial"
562 depends on MAGIC_SYSRQ
565 Many embedded boards have a disconnected TTL level serial which can
566 generate some garbage that can lead to spurious false sysrq detects.
567 This option allows you to decide whether you want to enable the
570 config MAGIC_SYSRQ_SERIAL_SEQUENCE
571 string "Char sequence that enables magic SysRq over serial"
572 depends on MAGIC_SYSRQ_SERIAL
575 Specifies a sequence of characters that can follow BREAK to enable
576 SysRq on a serial console.
578 If unsure, leave an empty string and the option will not be enabled.
581 bool "Debug Filesystem"
583 debugfs is a virtual file system that kernel developers use to put
584 debugging files into. Enable this option to be able to read and
585 write to these files.
587 For detailed documentation on the debugfs API, see
588 Documentation/filesystems/.
593 prompt "Debugfs default access"
595 default DEBUG_FS_ALLOW_ALL
597 This selects the default access restrictions for debugfs.
598 It can be overridden with kernel command line option
599 debugfs=[on,no-mount,off]. The restrictions apply for API access
600 and filesystem registration.
602 config DEBUG_FS_ALLOW_ALL
605 No restrictions apply. Both API and filesystem registration
606 is on. This is the normal default operation.
608 config DEBUG_FS_DISALLOW_MOUNT
609 bool "Do not register debugfs as filesystem"
611 The API is open but filesystem is not loaded. Clients can still do
612 their work and read with debug tools that do not need
615 config DEBUG_FS_ALLOW_NONE
618 Access is off. Clients get -PERM when trying to create nodes in
619 debugfs tree and debugfs is not registered as a filesystem.
620 Client can then back-off or continue without debugfs access.
624 source "lib/Kconfig.kgdb"
625 source "lib/Kconfig.ubsan"
626 source "lib/Kconfig.kcsan"
630 menu "Networking Debugging"
632 source "net/Kconfig.debug"
634 endmenu # "Networking Debugging"
636 menu "Memory Debugging"
638 source "mm/Kconfig.debug"
641 bool "Debug object operations"
642 depends on DEBUG_KERNEL
644 If you say Y here, additional code will be inserted into the
645 kernel to track the life time of various objects and validate
646 the operations on those objects.
648 config DEBUG_OBJECTS_SELFTEST
649 bool "Debug objects selftest"
650 depends on DEBUG_OBJECTS
652 This enables the selftest of the object debug code.
654 config DEBUG_OBJECTS_FREE
655 bool "Debug objects in freed memory"
656 depends on DEBUG_OBJECTS
658 This enables checks whether a k/v free operation frees an area
659 which contains an object which has not been deactivated
660 properly. This can make kmalloc/kfree-intensive workloads
663 config DEBUG_OBJECTS_TIMERS
664 bool "Debug timer objects"
665 depends on DEBUG_OBJECTS
667 If you say Y here, additional code will be inserted into the
668 timer routines to track the life time of timer objects and
669 validate the timer operations.
671 config DEBUG_OBJECTS_WORK
672 bool "Debug work objects"
673 depends on DEBUG_OBJECTS
675 If you say Y here, additional code will be inserted into the
676 work queue routines to track the life time of work objects and
677 validate the work operations.
679 config DEBUG_OBJECTS_RCU_HEAD
680 bool "Debug RCU callbacks objects"
681 depends on DEBUG_OBJECTS
683 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
685 config DEBUG_OBJECTS_PERCPU_COUNTER
686 bool "Debug percpu counter objects"
687 depends on DEBUG_OBJECTS
689 If you say Y here, additional code will be inserted into the
690 percpu counter routines to track the life time of percpu counter
691 objects and validate the percpu counter operations.
693 config DEBUG_OBJECTS_ENABLE_DEFAULT
694 int "debug_objects bootup default value (0-1)"
697 depends on DEBUG_OBJECTS
699 Debug objects boot parameter default value
701 config HAVE_DEBUG_KMEMLEAK
704 config DEBUG_KMEMLEAK
705 bool "Kernel memory leak detector"
706 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
708 select STACKTRACE if STACKTRACE_SUPPORT
712 Say Y here if you want to enable the memory leak
713 detector. The memory allocation/freeing is traced in a way
714 similar to the Boehm's conservative garbage collector, the
715 difference being that the orphan objects are not freed but
716 only shown in /sys/kernel/debug/kmemleak. Enabling this
717 feature will introduce an overhead to memory
718 allocations. See Documentation/dev-tools/kmemleak.rst for more
721 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
722 of finding leaks due to the slab objects poisoning.
724 In order to access the kmemleak file, debugfs needs to be
725 mounted (usually at /sys/kernel/debug).
727 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
728 int "Kmemleak memory pool size"
729 depends on DEBUG_KMEMLEAK
733 Kmemleak must track all the memory allocations to avoid
734 reporting false positives. Since memory may be allocated or
735 freed before kmemleak is fully initialised, use a static pool
736 of metadata objects to track such callbacks. After kmemleak is
737 fully initialised, this memory pool acts as an emergency one
738 if slab allocations fail.
740 config DEBUG_KMEMLEAK_TEST
741 tristate "Simple test for the kernel memory leak detector"
742 depends on DEBUG_KMEMLEAK && m
744 This option enables a module that explicitly leaks memory.
748 config DEBUG_KMEMLEAK_DEFAULT_OFF
749 bool "Default kmemleak to off"
750 depends on DEBUG_KMEMLEAK
752 Say Y here to disable kmemleak by default. It can then be enabled
753 on the command line via kmemleak=on.
755 config DEBUG_KMEMLEAK_AUTO_SCAN
756 bool "Enable kmemleak auto scan thread on boot up"
758 depends on DEBUG_KMEMLEAK
760 Depending on the cpu, kmemleak scan may be cpu intensive and can
761 stall user tasks at times. This option enables/disables automatic
762 kmemleak scan at boot up.
764 Say N here to disable kmemleak auto scan thread to stop automatic
765 scanning. Disabling this option disables automatic reporting of
770 config DEBUG_STACK_USAGE
771 bool "Stack utilization instrumentation"
772 depends on DEBUG_KERNEL && !IA64
774 Enables the display of the minimum amount of free stack which each
775 task has ever had available in the sysrq-T and sysrq-P debug output.
777 This option will slow down process creation somewhat.
779 config SCHED_STACK_END_CHECK
780 bool "Detect stack corruption on calls to schedule()"
781 depends on DEBUG_KERNEL
784 This option checks for a stack overrun on calls to schedule().
785 If the stack end location is found to be over written always panic as
786 the content of the corrupted region can no longer be trusted.
787 This is to ensure no erroneous behaviour occurs which could result in
788 data corruption or a sporadic crash at a later stage once the region
789 is examined. The runtime overhead introduced is minimal.
791 config ARCH_HAS_DEBUG_VM_PGTABLE
794 An architecture should select this when it can successfully
795 build and run DEBUG_VM_PGTABLE.
799 depends on DEBUG_KERNEL
801 Enable this to turn on extended checks in the virtual-memory system
802 that may impact performance.
806 config DEBUG_VM_VMACACHE
807 bool "Debug VMA caching"
810 Enable this to turn on VMA caching debug information. Doing so
811 can cause significant overhead, so only enable it in non-production
817 bool "Debug VM red-black trees"
820 Enable VM red-black tree debugging information and extra validations.
824 config DEBUG_VM_PGFLAGS
825 bool "Debug page-flags operations"
828 Enables extra validation on page flags operations.
832 config DEBUG_VM_PGTABLE
833 bool "Debug arch page table for semantics compliance"
835 depends on ARCH_HAS_DEBUG_VM_PGTABLE
836 default y if DEBUG_VM
838 This option provides a debug method which can be used to test
839 architecture page table helper functions on various platforms in
840 verifying if they comply with expected generic MM semantics. This
841 will help architecture code in making sure that any changes or
842 new additions of these helpers still conform to expected
843 semantics of the generic MM. Platforms will have to opt in for
844 this through ARCH_HAS_DEBUG_VM_PGTABLE.
848 config ARCH_HAS_DEBUG_VIRTUAL
852 bool "Debug VM translations"
853 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
855 Enable some costly sanity checks in virtual to page code. This can
856 catch mistakes with virt_to_page() and friends.
860 config DEBUG_NOMMU_REGIONS
861 bool "Debug the global anon/private NOMMU mapping region tree"
862 depends on DEBUG_KERNEL && !MMU
864 This option causes the global tree of anonymous and private mapping
865 regions to be regularly checked for invalid topology.
867 config DEBUG_MEMORY_INIT
868 bool "Debug memory initialisation" if EXPERT
871 Enable this for additional checks during memory initialisation.
872 The sanity checks verify aspects of the VM such as the memory model
873 and other information provided by the architecture. Verbose
874 information will be printed at KERN_DEBUG loglevel depending
875 on the mminit_loglevel= command-line option.
879 config MEMORY_NOTIFIER_ERROR_INJECT
880 tristate "Memory hotplug notifier error injection module"
881 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
883 This option provides the ability to inject artificial errors to
884 memory hotplug notifier chain callbacks. It is controlled through
885 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
887 If the notifier call chain should be failed with some events
888 notified, write the error code to "actions/<notifier event>/error".
890 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
892 # cd /sys/kernel/debug/notifier-error-inject/memory
893 # echo -12 > actions/MEM_GOING_OFFLINE/error
894 # echo offline > /sys/devices/system/memory/memoryXXX/state
895 bash: echo: write error: Cannot allocate memory
897 To compile this code as a module, choose M here: the module will
898 be called memory-notifier-error-inject.
902 config DEBUG_PER_CPU_MAPS
903 bool "Debug access to per_cpu maps"
904 depends on DEBUG_KERNEL
907 Say Y to verify that the per_cpu map being accessed has
908 been set up. This adds a fair amount of code to kernel memory
909 and decreases performance.
913 config DEBUG_KMAP_LOCAL
914 bool "Debug kmap_local temporary mappings"
915 depends on DEBUG_KERNEL && KMAP_LOCAL
917 This option enables additional error checking for the kmap_local
918 infrastructure. Disable for production use.
920 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
923 config DEBUG_KMAP_LOCAL_FORCE_MAP
924 bool "Enforce kmap_local temporary mappings"
925 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
927 select DEBUG_KMAP_LOCAL
929 This option enforces temporary mappings through the kmap_local
930 mechanism for non-highmem pages and on non-highmem systems.
931 Disable this for production systems!
934 bool "Highmem debugging"
935 depends on DEBUG_KERNEL && HIGHMEM
936 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
937 select DEBUG_KMAP_LOCAL
939 This option enables additional error checking for high memory
940 systems. Disable for production systems.
942 config HAVE_DEBUG_STACKOVERFLOW
945 config DEBUG_STACKOVERFLOW
946 bool "Check for stack overflows"
947 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
949 Say Y here if you want to check for overflows of kernel, IRQ
950 and exception stacks (if your architecture uses them). This
951 option will show detailed messages if free stack space drops
952 below a certain limit.
954 These kinds of bugs usually occur when call-chains in the
955 kernel get too deep, especially when interrupts are
958 Use this in cases where you see apparently random memory
959 corruption, especially if it appears in 'struct thread_info'
961 If in doubt, say "N".
963 source "lib/Kconfig.kasan"
964 source "lib/Kconfig.kfence"
966 endmenu # "Memory Debugging"
969 bool "Debug shared IRQ handlers"
970 depends on DEBUG_KERNEL
972 Enable this to generate a spurious interrupt just before a shared
973 interrupt handler is deregistered (generating one when registering
974 is currently disabled). Drivers need to handle this correctly. Some
975 don't and need to be caught.
977 menu "Debug Oops, Lockups and Hangs"
982 Say Y here to enable the kernel to panic when it oopses. This
983 has the same effect as setting oops=panic on the kernel command
986 This feature is useful to ensure that the kernel does not do
987 anything erroneous after an oops which could result in data
988 corruption or other issues.
992 config PANIC_ON_OOPS_VALUE
995 default 0 if !PANIC_ON_OOPS
996 default 1 if PANIC_ON_OOPS
1002 Set the timeout value (in seconds) until a reboot occurs when
1003 the kernel panics. If n = 0, then we wait forever. A timeout
1004 value n > 0 will wait n seconds before rebooting, while a timeout
1005 value n < 0 will reboot immediately.
1007 config LOCKUP_DETECTOR
1010 config SOFTLOCKUP_DETECTOR
1011 bool "Detect Soft Lockups"
1012 depends on DEBUG_KERNEL && !S390
1013 select LOCKUP_DETECTOR
1015 Say Y here to enable the kernel to act as a watchdog to detect
1018 Softlockups are bugs that cause the kernel to loop in kernel
1019 mode for more than 20 seconds, without giving other tasks a
1020 chance to run. The current stack trace is displayed upon
1021 detection and the system will stay locked up.
1023 config BOOTPARAM_SOFTLOCKUP_PANIC
1024 bool "Panic (Reboot) On Soft Lockups"
1025 depends on SOFTLOCKUP_DETECTOR
1027 Say Y here to enable the kernel to panic on "soft lockups",
1028 which are bugs that cause the kernel to loop in kernel
1029 mode for more than 20 seconds (configurable using the watchdog_thresh
1030 sysctl), without giving other tasks a chance to run.
1032 The panic can be used in combination with panic_timeout,
1033 to cause the system to reboot automatically after a
1034 lockup has been detected. This feature is useful for
1035 high-availability systems that have uptime guarantees and
1036 where a lockup must be resolved ASAP.
1040 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
1042 depends on SOFTLOCKUP_DETECTOR
1044 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
1045 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
1047 config HARDLOCKUP_DETECTOR_PERF
1049 select SOFTLOCKUP_DETECTOR
1052 # Enables a timestamp based low pass filter to compensate for perf based
1053 # hard lockup detection which runs too fast due to turbo modes.
1055 config HARDLOCKUP_CHECK_TIMESTAMP
1059 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1060 # lockup detector rather than the perf based detector.
1062 config HARDLOCKUP_DETECTOR
1063 bool "Detect Hard Lockups"
1064 depends on DEBUG_KERNEL && !S390
1065 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1066 select LOCKUP_DETECTOR
1067 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1069 Say Y here to enable the kernel to act as a watchdog to detect
1072 Hardlockups are bugs that cause the CPU to loop in kernel mode
1073 for more than 10 seconds, without letting other interrupts have a
1074 chance to run. The current stack trace is displayed upon detection
1075 and the system will stay locked up.
1077 config BOOTPARAM_HARDLOCKUP_PANIC
1078 bool "Panic (Reboot) On Hard Lockups"
1079 depends on HARDLOCKUP_DETECTOR
1081 Say Y here to enable the kernel to panic on "hard lockups",
1082 which are bugs that cause the kernel to loop in kernel
1083 mode with interrupts disabled for more than 10 seconds (configurable
1084 using the watchdog_thresh sysctl).
1088 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
1090 depends on HARDLOCKUP_DETECTOR
1092 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
1093 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
1095 config DETECT_HUNG_TASK
1096 bool "Detect Hung Tasks"
1097 depends on DEBUG_KERNEL
1098 default SOFTLOCKUP_DETECTOR
1100 Say Y here to enable the kernel to detect "hung tasks",
1101 which are bugs that cause the task to be stuck in
1102 uninterruptible "D" state indefinitely.
1104 When a hung task is detected, the kernel will print the
1105 current stack trace (which you should report), but the
1106 task will stay in uninterruptible state. If lockdep is
1107 enabled then all held locks will also be reported. This
1108 feature has negligible overhead.
1110 config DEFAULT_HUNG_TASK_TIMEOUT
1111 int "Default timeout for hung task detection (in seconds)"
1112 depends on DETECT_HUNG_TASK
1115 This option controls the default timeout (in seconds) used
1116 to determine when a task has become non-responsive and should
1119 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1120 sysctl or by writing a value to
1121 /proc/sys/kernel/hung_task_timeout_secs.
1123 A timeout of 0 disables the check. The default is two minutes.
1124 Keeping the default should be fine in most cases.
1126 config BOOTPARAM_HUNG_TASK_PANIC
1127 bool "Panic (Reboot) On Hung Tasks"
1128 depends on DETECT_HUNG_TASK
1130 Say Y here to enable the kernel to panic on "hung tasks",
1131 which are bugs that cause the kernel to leave a task stuck
1132 in uninterruptible "D" state.
1134 The panic can be used in combination with panic_timeout,
1135 to cause the system to reboot automatically after a
1136 hung task has been detected. This feature is useful for
1137 high-availability systems that have uptime guarantees and
1138 where a hung tasks must be resolved ASAP.
1142 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
1144 depends on DETECT_HUNG_TASK
1146 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
1147 default 1 if BOOTPARAM_HUNG_TASK_PANIC
1150 bool "Detect Workqueue Stalls"
1151 depends on DEBUG_KERNEL
1153 Say Y here to enable stall detection on workqueues. If a
1154 worker pool doesn't make forward progress on a pending work
1155 item for over a given amount of time, 30s by default, a
1156 warning message is printed along with dump of workqueue
1157 state. This can be configured through kernel parameter
1158 "workqueue.watchdog_thresh" and its sysfs counterpart.
1161 tristate "Test module to generate lockups"
1164 This builds the "test_lockup" module that helps to make sure
1165 that watchdogs and lockup detectors are working properly.
1167 Depending on module parameters it could emulate soft or hard
1168 lockup, "hung task", or locking arbitrary lock for a long time.
1169 Also it could generate series of lockups with cooling-down periods.
1173 endmenu # "Debug lockups and hangs"
1175 menu "Scheduler Debugging"
1178 bool "Collect scheduler debugging info"
1179 depends on DEBUG_KERNEL && PROC_FS
1182 If you say Y here, the /proc/sched_debug file will be provided
1183 that can help debug the scheduler. The runtime overhead of this
1191 bool "Collect scheduler statistics"
1192 depends on DEBUG_KERNEL && PROC_FS
1195 If you say Y here, additional code will be inserted into the
1196 scheduler and related routines to collect statistics about
1197 scheduler behavior and provide them in /proc/schedstat. These
1198 stats may be useful for both tuning and debugging the scheduler
1199 If you aren't debugging the scheduler or trying to tune a specific
1200 application, you can say N to avoid the very slight overhead
1205 config DEBUG_TIMEKEEPING
1206 bool "Enable extra timekeeping sanity checking"
1208 This option will enable additional timekeeping sanity checks
1209 which may be helpful when diagnosing issues where timekeeping
1210 problems are suspected.
1212 This may include checks in the timekeeping hotpaths, so this
1213 option may have a (very small) performance impact to some
1218 config DEBUG_PREEMPT
1219 bool "Debug preemptible kernel"
1220 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1223 If you say Y here then the kernel will use a debug variant of the
1224 commonly used smp_processor_id() function and will print warnings
1225 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1226 will detect preemption count underflows.
1228 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1230 config LOCK_DEBUGGING_SUPPORT
1232 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1235 config PROVE_LOCKING
1236 bool "Lock debugging: prove locking correctness"
1237 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1239 select DEBUG_SPINLOCK
1240 select DEBUG_MUTEXES if !PREEMPT_RT
1241 select DEBUG_RT_MUTEXES if RT_MUTEXES
1243 select DEBUG_WW_MUTEX_SLOWPATH
1244 select DEBUG_LOCK_ALLOC
1245 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1246 select TRACE_IRQFLAGS
1249 This feature enables the kernel to prove that all locking
1250 that occurs in the kernel runtime is mathematically
1251 correct: that under no circumstance could an arbitrary (and
1252 not yet triggered) combination of observed locking
1253 sequences (on an arbitrary number of CPUs, running an
1254 arbitrary number of tasks and interrupt contexts) cause a
1257 In short, this feature enables the kernel to report locking
1258 related deadlocks before they actually occur.
1260 The proof does not depend on how hard and complex a
1261 deadlock scenario would be to trigger: how many
1262 participant CPUs, tasks and irq-contexts would be needed
1263 for it to trigger. The proof also does not depend on
1264 timing: if a race and a resulting deadlock is possible
1265 theoretically (no matter how unlikely the race scenario
1266 is), it will be proven so and will immediately be
1267 reported by the kernel (once the event is observed that
1268 makes the deadlock theoretically possible).
1270 If a deadlock is impossible (i.e. the locking rules, as
1271 observed by the kernel, are mathematically correct), the
1272 kernel reports nothing.
1274 NOTE: this feature can also be enabled for rwlocks, mutexes
1275 and rwsems - in which case all dependencies between these
1276 different locking variants are observed and mapped too, and
1277 the proof of observed correctness is also maintained for an
1278 arbitrary combination of these separate locking variants.
1280 For more details, see Documentation/locking/lockdep-design.rst.
1282 config PROVE_RAW_LOCK_NESTING
1283 bool "Enable raw_spinlock - spinlock nesting checks"
1284 depends on PROVE_LOCKING
1287 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1288 that the lock nesting rules for PREEMPT_RT enabled kernels are
1291 NOTE: There are known nesting problems. So if you enable this
1292 option expect lockdep splats until these problems have been fully
1293 addressed which is work in progress. This config switch allows to
1294 identify and analyze these problems. It will be removed and the
1295 check permanently enabled once the main issues have been fixed.
1297 If unsure, select N.
1300 bool "Lock usage statistics"
1301 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1303 select DEBUG_SPINLOCK
1304 select DEBUG_MUTEXES if !PREEMPT_RT
1305 select DEBUG_RT_MUTEXES if RT_MUTEXES
1306 select DEBUG_LOCK_ALLOC
1309 This feature enables tracking lock contention points
1311 For more details, see Documentation/locking/lockstat.rst
1313 This also enables lock events required by "perf lock",
1315 If you want to use "perf lock", you also need to turn on
1316 CONFIG_EVENT_TRACING.
1318 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1319 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1321 config DEBUG_RT_MUTEXES
1322 bool "RT Mutex debugging, deadlock detection"
1323 depends on DEBUG_KERNEL && RT_MUTEXES
1325 This allows rt mutex semantics violations and rt mutex related
1326 deadlocks (lockups) to be detected and reported automatically.
1328 config DEBUG_SPINLOCK
1329 bool "Spinlock and rw-lock debugging: basic checks"
1330 depends on DEBUG_KERNEL
1331 select UNINLINE_SPIN_UNLOCK
1333 Say Y here and build SMP to catch missing spinlock initialization
1334 and certain other kinds of spinlock errors commonly made. This is
1335 best used in conjunction with the NMI watchdog so that spinlock
1336 deadlocks are also debuggable.
1338 config DEBUG_MUTEXES
1339 bool "Mutex debugging: basic checks"
1340 depends on DEBUG_KERNEL && !PREEMPT_RT
1342 This feature allows mutex semantics violations to be detected and
1345 config DEBUG_WW_MUTEX_SLOWPATH
1346 bool "Wait/wound mutex debugging: Slowpath testing"
1347 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1348 select DEBUG_LOCK_ALLOC
1349 select DEBUG_SPINLOCK
1350 select DEBUG_MUTEXES if !PREEMPT_RT
1351 select DEBUG_RT_MUTEXES if PREEMPT_RT
1353 This feature enables slowpath testing for w/w mutex users by
1354 injecting additional -EDEADLK wound/backoff cases. Together with
1355 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1356 will test all possible w/w mutex interface abuse with the
1357 exception of simply not acquiring all the required locks.
1358 Note that this feature can introduce significant overhead, so
1359 it really should not be enabled in a production or distro kernel,
1360 even a debug kernel. If you are a driver writer, enable it. If
1361 you are a distro, do not.
1364 bool "RW Semaphore debugging: basic checks"
1365 depends on DEBUG_KERNEL
1367 This debugging feature allows mismatched rw semaphore locks
1368 and unlocks to be detected and reported.
1370 config DEBUG_LOCK_ALLOC
1371 bool "Lock debugging: detect incorrect freeing of live locks"
1372 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1373 select DEBUG_SPINLOCK
1374 select DEBUG_MUTEXES if !PREEMPT_RT
1375 select DEBUG_RT_MUTEXES if RT_MUTEXES
1378 This feature will check whether any held lock (spinlock, rwlock,
1379 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1380 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1381 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1382 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1383 held during task exit.
1387 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1392 config LOCKDEP_SMALL
1396 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1397 depends on LOCKDEP && !LOCKDEP_SMALL
1401 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1403 config LOCKDEP_CHAINS_BITS
1404 int "Bitsize for MAX_LOCKDEP_CHAINS"
1405 depends on LOCKDEP && !LOCKDEP_SMALL
1409 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1411 config LOCKDEP_STACK_TRACE_BITS
1412 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1413 depends on LOCKDEP && !LOCKDEP_SMALL
1417 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1419 config LOCKDEP_STACK_TRACE_HASH_BITS
1420 int "Bitsize for STACK_TRACE_HASH_SIZE"
1421 depends on LOCKDEP && !LOCKDEP_SMALL
1425 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1427 config LOCKDEP_CIRCULAR_QUEUE_BITS
1428 int "Bitsize for elements in circular_queue struct"
1433 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1435 config DEBUG_LOCKDEP
1436 bool "Lock dependency engine debugging"
1437 depends on DEBUG_KERNEL && LOCKDEP
1438 select DEBUG_IRQFLAGS
1440 If you say Y here, the lock dependency engine will do
1441 additional runtime checks to debug itself, at the price
1442 of more runtime overhead.
1444 config DEBUG_ATOMIC_SLEEP
1445 bool "Sleep inside atomic section checking"
1446 select PREEMPT_COUNT
1447 depends on DEBUG_KERNEL
1448 depends on !ARCH_NO_PREEMPT
1450 If you say Y here, various routines which may sleep will become very
1451 noisy if they are called inside atomic sections: when a spinlock is
1452 held, inside an rcu read side critical section, inside preempt disabled
1453 sections, inside an interrupt, etc...
1455 config DEBUG_LOCKING_API_SELFTESTS
1456 bool "Locking API boot-time self-tests"
1457 depends on DEBUG_KERNEL
1459 Say Y here if you want the kernel to run a short self-test during
1460 bootup. The self-test checks whether common types of locking bugs
1461 are detected by debugging mechanisms or not. (if you disable
1462 lock debugging then those bugs won't be detected of course.)
1463 The following locking APIs are covered: spinlocks, rwlocks,
1466 config LOCK_TORTURE_TEST
1467 tristate "torture tests for locking"
1468 depends on DEBUG_KERNEL
1471 This option provides a kernel module that runs torture tests
1472 on kernel locking primitives. The kernel module may be built
1473 after the fact on the running kernel to be tested, if desired.
1475 Say Y here if you want kernel locking-primitive torture tests
1476 to be built into the kernel.
1477 Say M if you want these torture tests to build as a module.
1478 Say N if you are unsure.
1480 config WW_MUTEX_SELFTEST
1481 tristate "Wait/wound mutex selftests"
1483 This option provides a kernel module that runs tests on the
1484 on the struct ww_mutex locking API.
1486 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1487 with this test harness.
1489 Say M if you want these self tests to build as a module.
1490 Say N if you are unsure.
1492 config SCF_TORTURE_TEST
1493 tristate "torture tests for smp_call_function*()"
1494 depends on DEBUG_KERNEL
1497 This option provides a kernel module that runs torture tests
1498 on the smp_call_function() family of primitives. The kernel
1499 module may be built after the fact on the running kernel to
1500 be tested, if desired.
1502 config CSD_LOCK_WAIT_DEBUG
1503 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1504 depends on DEBUG_KERNEL
1508 This option enables debug prints when CPUs are slow to respond
1509 to the smp_call_function*() IPI wrappers. These debug prints
1510 include the IPI handler function currently executing (if any)
1511 and relevant stack traces.
1514 prompt "Lock debugging: prove subsystem device_lock() correctness"
1515 depends on PROVE_LOCKING
1517 For subsystems that have instrumented their usage of the device_lock()
1518 with nested annotations, enable lock dependency checking. The locking
1519 hierarchy 'subclass' identifiers are not compatible across
1520 sub-systems, so only one can be enabled at a time.
1522 config PROVE_NVDIMM_LOCKING
1524 depends on LIBNVDIMM
1526 Enable lockdep to validate nd_device_lock() usage.
1528 config PROVE_CXL_LOCKING
1532 Enable lockdep to validate cxl_device_lock() usage.
1536 endmenu # lock debugging
1538 config TRACE_IRQFLAGS
1539 depends on TRACE_IRQFLAGS_SUPPORT
1542 Enables hooks to interrupt enabling and disabling for
1543 either tracing or lock debugging.
1545 config TRACE_IRQFLAGS_NMI
1547 depends on TRACE_IRQFLAGS
1548 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1550 config DEBUG_IRQFLAGS
1551 bool "Debug IRQ flag manipulation"
1553 Enables checks for potentially unsafe enabling or disabling of
1554 interrupts, such as calling raw_local_irq_restore() when interrupts
1558 bool "Stack backtrace support"
1559 depends on STACKTRACE_SUPPORT
1561 This option causes the kernel to create a /proc/pid/stack for
1562 every process, showing its current stack trace.
1563 It is also used by various kernel debugging features that require
1564 stack trace generation.
1566 config WARN_ALL_UNSEEDED_RANDOM
1567 bool "Warn for all uses of unseeded randomness"
1570 Some parts of the kernel contain bugs relating to their use of
1571 cryptographically secure random numbers before it's actually possible
1572 to generate those numbers securely. This setting ensures that these
1573 flaws don't go unnoticed, by enabling a message, should this ever
1574 occur. This will allow people with obscure setups to know when things
1575 are going wrong, so that they might contact developers about fixing
1578 Unfortunately, on some models of some architectures getting
1579 a fully seeded CRNG is extremely difficult, and so this can
1580 result in dmesg getting spammed for a surprisingly long
1581 time. This is really bad from a security perspective, and
1582 so architecture maintainers really need to do what they can
1583 to get the CRNG seeded sooner after the system is booted.
1584 However, since users cannot do anything actionable to
1585 address this, by default the kernel will issue only a single
1586 warning for the first use of unseeded randomness.
1588 Say Y here if you want to receive warnings for all uses of
1589 unseeded randomness. This will be of use primarily for
1590 those developers interested in improving the security of
1591 Linux kernels running on their architecture (or
1594 config DEBUG_KOBJECT
1595 bool "kobject debugging"
1596 depends on DEBUG_KERNEL
1598 If you say Y here, some extra kobject debugging messages will be sent
1601 config DEBUG_KOBJECT_RELEASE
1602 bool "kobject release debugging"
1603 depends on DEBUG_OBJECTS_TIMERS
1605 kobjects are reference counted objects. This means that their
1606 last reference count put is not predictable, and the kobject can
1607 live on past the point at which a driver decides to drop it's
1608 initial reference to the kobject gained on allocation. An
1609 example of this would be a struct device which has just been
1612 However, some buggy drivers assume that after such an operation,
1613 the memory backing the kobject can be immediately freed. This
1614 goes completely against the principles of a refcounted object.
1616 If you say Y here, the kernel will delay the release of kobjects
1617 on the last reference count to improve the visibility of this
1618 kind of kobject release bug.
1620 config HAVE_DEBUG_BUGVERBOSE
1623 menu "Debug kernel data structures"
1626 bool "Debug linked list manipulation"
1627 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1629 Enable this to turn on extended checks in the linked-list
1635 bool "Debug priority linked list manipulation"
1636 depends on DEBUG_KERNEL
1638 Enable this to turn on extended checks in the priority-ordered
1639 linked-list (plist) walking routines. This checks the entire
1640 list multiple times during each manipulation.
1645 bool "Debug SG table operations"
1646 depends on DEBUG_KERNEL
1648 Enable this to turn on checks on scatter-gather tables. This can
1649 help find problems with drivers that do not properly initialize
1654 config DEBUG_NOTIFIERS
1655 bool "Debug notifier call chains"
1656 depends on DEBUG_KERNEL
1658 Enable this to turn on sanity checking for notifier call chains.
1659 This is most useful for kernel developers to make sure that
1660 modules properly unregister themselves from notifier chains.
1661 This is a relatively cheap check but if you care about maximum
1664 config BUG_ON_DATA_CORRUPTION
1665 bool "Trigger a BUG when data corruption is detected"
1668 Select this option if the kernel should BUG when it encounters
1669 data corruption in kernel memory structures when they get checked
1676 config DEBUG_CREDENTIALS
1677 bool "Debug credential management"
1678 depends on DEBUG_KERNEL
1680 Enable this to turn on some debug checking for credential
1681 management. The additional code keeps track of the number of
1682 pointers from task_structs to any given cred struct, and checks to
1683 see that this number never exceeds the usage count of the cred
1686 Furthermore, if SELinux is enabled, this also checks that the
1687 security pointer in the cred struct is never seen to be invalid.
1691 source "kernel/rcu/Kconfig.debug"
1693 config DEBUG_WQ_FORCE_RR_CPU
1694 bool "Force round-robin CPU selection for unbound work items"
1695 depends on DEBUG_KERNEL
1698 Workqueue used to implicitly guarantee that work items queued
1699 without explicit CPU specified are put on the local CPU. This
1700 guarantee is no longer true and while local CPU is still
1701 preferred work items may be put on foreign CPUs. Kernel
1702 parameter "workqueue.debug_force_rr_cpu" is added to force
1703 round-robin CPU selection to flush out usages which depend on the
1704 now broken guarantee. This config option enables the debug
1705 feature by default. When enabled, memory and cache locality will
1708 config CPU_HOTPLUG_STATE_CONTROL
1709 bool "Enable CPU hotplug state control"
1710 depends on DEBUG_KERNEL
1711 depends on HOTPLUG_CPU
1714 Allows to write steps between "offline" and "online" to the CPUs
1715 sysfs target file so states can be stepped granular. This is a debug
1716 option for now as the hotplug machinery cannot be stopped and
1717 restarted at arbitrary points yet.
1719 Say N if your are unsure.
1722 bool "Latency measuring infrastructure"
1723 depends on DEBUG_KERNEL
1724 depends on STACKTRACE_SUPPORT
1726 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1732 Enable this option if you want to use the LatencyTOP tool
1733 to find out which userspace is blocking on what kernel operations.
1735 source "kernel/trace/Kconfig"
1737 config PROVIDE_OHCI1394_DMA_INIT
1738 bool "Remote debugging over FireWire early on boot"
1739 depends on PCI && X86
1741 If you want to debug problems which hang or crash the kernel early
1742 on boot and the crashing machine has a FireWire port, you can use
1743 this feature to remotely access the memory of the crashed machine
1744 over FireWire. This employs remote DMA as part of the OHCI1394
1745 specification which is now the standard for FireWire controllers.
1747 With remote DMA, you can monitor the printk buffer remotely using
1748 firescope and access all memory below 4GB using fireproxy from gdb.
1749 Even controlling a kernel debugger is possible using remote DMA.
1753 If ohci1394_dma=early is used as boot parameter, it will initialize
1754 all OHCI1394 controllers which are found in the PCI config space.
1756 As all changes to the FireWire bus such as enabling and disabling
1757 devices cause a bus reset and thereby disable remote DMA for all
1758 devices, be sure to have the cable plugged and FireWire enabled on
1759 the debugging host before booting the debug target for debugging.
1761 This code (~1k) is freed after boot. By then, the firewire stack
1762 in charge of the OHCI-1394 controllers should be used instead.
1764 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1766 source "samples/Kconfig"
1768 config ARCH_HAS_DEVMEM_IS_ALLOWED
1771 config STRICT_DEVMEM
1772 bool "Filter access to /dev/mem"
1773 depends on MMU && DEVMEM
1774 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1775 default y if PPC || X86 || ARM64
1777 If this option is disabled, you allow userspace (root) access to all
1778 of memory, including kernel and userspace memory. Accidental
1779 access to this is obviously disastrous, but specific access can
1780 be used by people debugging the kernel. Note that with PAT support
1781 enabled, even in this case there are restrictions on /dev/mem
1782 use due to the cache aliasing requirements.
1784 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1785 file only allows userspace access to PCI space and the BIOS code and
1786 data regions. This is sufficient for dosemu and X and all common
1791 config IO_STRICT_DEVMEM
1792 bool "Filter I/O access to /dev/mem"
1793 depends on STRICT_DEVMEM
1795 If this option is disabled, you allow userspace (root) access to all
1796 io-memory regardless of whether a driver is actively using that
1797 range. Accidental access to this is obviously disastrous, but
1798 specific access can be used by people debugging kernel drivers.
1800 If this option is switched on, the /dev/mem file only allows
1801 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1802 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1803 if the driver using a given range cannot be disabled.
1807 menu "$(SRCARCH) Debugging"
1809 source "arch/$(SRCARCH)/Kconfig.debug"
1813 menu "Kernel Testing and Coverage"
1815 source "lib/kunit/Kconfig"
1817 config NOTIFIER_ERROR_INJECTION
1818 tristate "Notifier error injection"
1819 depends on DEBUG_KERNEL
1822 This option provides the ability to inject artificial errors to
1823 specified notifier chain callbacks. It is useful to test the error
1824 handling of notifier call chain failures.
1828 config PM_NOTIFIER_ERROR_INJECT
1829 tristate "PM notifier error injection module"
1830 depends on PM && NOTIFIER_ERROR_INJECTION
1831 default m if PM_DEBUG
1833 This option provides the ability to inject artificial errors to
1834 PM notifier chain callbacks. It is controlled through debugfs
1835 interface /sys/kernel/debug/notifier-error-inject/pm
1837 If the notifier call chain should be failed with some events
1838 notified, write the error code to "actions/<notifier event>/error".
1840 Example: Inject PM suspend error (-12 = -ENOMEM)
1842 # cd /sys/kernel/debug/notifier-error-inject/pm/
1843 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1844 # echo mem > /sys/power/state
1845 bash: echo: write error: Cannot allocate memory
1847 To compile this code as a module, choose M here: the module will
1848 be called pm-notifier-error-inject.
1852 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1853 tristate "OF reconfig notifier error injection module"
1854 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1856 This option provides the ability to inject artificial errors to
1857 OF reconfig notifier chain callbacks. It is controlled
1858 through debugfs interface under
1859 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1861 If the notifier call chain should be failed with some events
1862 notified, write the error code to "actions/<notifier event>/error".
1864 To compile this code as a module, choose M here: the module will
1865 be called of-reconfig-notifier-error-inject.
1869 config NETDEV_NOTIFIER_ERROR_INJECT
1870 tristate "Netdev notifier error injection module"
1871 depends on NET && NOTIFIER_ERROR_INJECTION
1873 This option provides the ability to inject artificial errors to
1874 netdevice notifier chain callbacks. It is controlled through debugfs
1875 interface /sys/kernel/debug/notifier-error-inject/netdev
1877 If the notifier call chain should be failed with some events
1878 notified, write the error code to "actions/<notifier event>/error".
1880 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1882 # cd /sys/kernel/debug/notifier-error-inject/netdev
1883 # echo -22 > actions/NETDEV_CHANGEMTU/error
1884 # ip link set eth0 mtu 1024
1885 RTNETLINK answers: Invalid argument
1887 To compile this code as a module, choose M here: the module will
1888 be called netdev-notifier-error-inject.
1892 config FUNCTION_ERROR_INJECTION
1894 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1896 config FAULT_INJECTION
1897 bool "Fault-injection framework"
1898 depends on DEBUG_KERNEL
1900 Provide fault-injection framework.
1901 For more details, see Documentation/fault-injection/.
1904 bool "Fault-injection capability for kmalloc"
1905 depends on FAULT_INJECTION
1906 depends on SLAB || SLUB
1908 Provide fault-injection capability for kmalloc.
1910 config FAIL_PAGE_ALLOC
1911 bool "Fault-injection capability for alloc_pages()"
1912 depends on FAULT_INJECTION
1914 Provide fault-injection capability for alloc_pages().
1916 config FAULT_INJECTION_USERCOPY
1917 bool "Fault injection capability for usercopy functions"
1918 depends on FAULT_INJECTION
1920 Provides fault-injection capability to inject failures
1921 in usercopy functions (copy_from_user(), get_user(), ...).
1923 config FAIL_MAKE_REQUEST
1924 bool "Fault-injection capability for disk IO"
1925 depends on FAULT_INJECTION && BLOCK
1927 Provide fault-injection capability for disk IO.
1929 config FAIL_IO_TIMEOUT
1930 bool "Fault-injection capability for faking disk interrupts"
1931 depends on FAULT_INJECTION && BLOCK
1933 Provide fault-injection capability on end IO handling. This
1934 will make the block layer "forget" an interrupt as configured,
1935 thus exercising the error handling.
1937 Only works with drivers that use the generic timeout handling,
1938 for others it won't do anything.
1941 bool "Fault-injection capability for futexes"
1943 depends on FAULT_INJECTION && FUTEX
1945 Provide fault-injection capability for futexes.
1947 config FAULT_INJECTION_DEBUG_FS
1948 bool "Debugfs entries for fault-injection capabilities"
1949 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1951 Enable configuration of fault-injection capabilities via debugfs.
1953 config FAIL_FUNCTION
1954 bool "Fault-injection capability for functions"
1955 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1957 Provide function-based fault-injection capability.
1958 This will allow you to override a specific function with a return
1959 with given return value. As a result, function caller will see
1960 an error value and have to handle it. This is useful to test the
1961 error handling in various subsystems.
1963 config FAIL_MMC_REQUEST
1964 bool "Fault-injection capability for MMC IO"
1965 depends on FAULT_INJECTION_DEBUG_FS && MMC
1967 Provide fault-injection capability for MMC IO.
1968 This will make the mmc core return data errors. This is
1969 useful to test the error handling in the mmc block device
1970 and to test how the mmc host driver handles retries from
1974 bool "Fault-injection capability for SunRPC"
1975 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1977 Provide fault-injection capability for SunRPC and
1980 config FAULT_INJECTION_STACKTRACE_FILTER
1981 bool "stacktrace filter for fault-injection capabilities"
1982 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1985 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1987 Provide stacktrace filter for fault-injection capabilities
1989 config ARCH_HAS_KCOV
1992 An architecture should select this when it can successfully
1993 build and run with CONFIG_KCOV. This typically requires
1994 disabling instrumentation for some early boot code.
1996 config CC_HAS_SANCOV_TRACE_PC
1997 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2001 bool "Code coverage for fuzzing"
2002 depends on ARCH_HAS_KCOV
2003 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2004 depends on !ARCH_WANTS_NO_INSTR || STACK_VALIDATION || \
2005 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
2007 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2009 KCOV exposes kernel code coverage information in a form suitable
2010 for coverage-guided fuzzing (randomized testing).
2012 If RANDOMIZE_BASE is enabled, PC values will not be stable across
2013 different machines and across reboots. If you need stable PC values,
2014 disable RANDOMIZE_BASE.
2016 For more details, see Documentation/dev-tools/kcov.rst.
2018 config KCOV_ENABLE_COMPARISONS
2019 bool "Enable comparison operands collection by KCOV"
2021 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2023 KCOV also exposes operands of every comparison in the instrumented
2024 code along with operand sizes and PCs of the comparison instructions.
2025 These operands can be used by fuzzing engines to improve the quality
2026 of fuzzing coverage.
2028 config KCOV_INSTRUMENT_ALL
2029 bool "Instrument all code by default"
2033 If you are doing generic system call fuzzing (like e.g. syzkaller),
2034 then you will want to instrument the whole kernel and you should
2035 say y here. If you are doing more targeted fuzzing (like e.g.
2036 filesystem fuzzing with AFL) then you will want to enable coverage
2037 for more specific subsets of files, and should say n here.
2039 config KCOV_IRQ_AREA_SIZE
2040 hex "Size of interrupt coverage collection area in words"
2044 KCOV uses preallocated per-cpu areas to collect coverage from
2045 soft interrupts. This specifies the size of those areas in the
2046 number of unsigned long words.
2048 menuconfig RUNTIME_TESTING_MENU
2049 bool "Runtime Testing"
2052 if RUNTIME_TESTING_MENU
2055 tristate "Linux Kernel Dump Test Tool Module"
2058 This module enables testing of the different dumping mechanisms by
2059 inducing system failures at predefined crash points.
2060 If you don't need it: say N
2061 Choose M here to compile this code as a module. The module will be
2064 Documentation on how to use the module can be found in
2065 Documentation/fault-injection/provoke-crashes.rst
2067 config TEST_LIST_SORT
2068 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2070 default KUNIT_ALL_TESTS
2072 Enable this to turn on 'list_sort()' function test. This test is
2073 executed only once during system boot (so affects only boot time),
2074 or at module load time.
2078 config TEST_MIN_HEAP
2079 tristate "Min heap test"
2080 depends on DEBUG_KERNEL || m
2082 Enable this to turn on min heap function tests. This test is
2083 executed only once during system boot (so affects only boot time),
2084 or at module load time.
2089 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2091 default KUNIT_ALL_TESTS
2093 This option enables the self-test function of 'sort()' at boot,
2094 or at module load time.
2099 tristate "64bit/32bit division and modulo test"
2100 depends on DEBUG_KERNEL || m
2102 Enable this to turn on 'do_div()' function test. This test is
2103 executed only once during system boot (so affects only boot time),
2104 or at module load time.
2108 config KPROBES_SANITY_TEST
2109 tristate "Kprobes sanity tests"
2110 depends on DEBUG_KERNEL
2114 This option provides for testing basic kprobes functionality on
2115 boot. Samples of kprobe and kretprobe are inserted and
2116 verified for functionality.
2118 Say N if you are unsure.
2120 config FPROBE_SANITY_TEST
2121 bool "Self test for fprobe"
2122 depends on DEBUG_KERNEL
2126 This option will enable testing the fprobe when the system boot.
2127 A series of tests are made to verify that the fprobe is functioning
2130 Say N if you are unsure.
2132 config BACKTRACE_SELF_TEST
2133 tristate "Self test for the backtrace code"
2134 depends on DEBUG_KERNEL
2136 This option provides a kernel module that can be used to test
2137 the kernel stack backtrace code. This option is not useful
2138 for distributions or general kernels, but only for kernel
2139 developers working on architecture code.
2141 Note that if you want to also test saved backtraces, you will
2142 have to enable STACKTRACE as well.
2144 Say N if you are unsure.
2146 config TEST_REF_TRACKER
2147 tristate "Self test for reference tracker"
2148 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2151 This option provides a kernel module performing tests
2152 using reference tracker infrastructure.
2154 Say N if you are unsure.
2157 tristate "Red-Black tree test"
2158 depends on DEBUG_KERNEL
2160 A benchmark measuring the performance of the rbtree library.
2161 Also includes rbtree invariant checks.
2163 config REED_SOLOMON_TEST
2164 tristate "Reed-Solomon library test"
2165 depends on DEBUG_KERNEL || m
2167 select REED_SOLOMON_ENC16
2168 select REED_SOLOMON_DEC16
2170 This option enables the self-test function of rslib at boot,
2171 or at module load time.
2175 config INTERVAL_TREE_TEST
2176 tristate "Interval tree test"
2177 depends on DEBUG_KERNEL
2178 select INTERVAL_TREE
2180 A benchmark measuring the performance of the interval tree library
2183 tristate "Per cpu operations test"
2184 depends on m && DEBUG_KERNEL
2186 Enable this option to build test module which validates per-cpu
2191 config ATOMIC64_SELFTEST
2192 tristate "Perform an atomic64_t self-test"
2194 Enable this option to test the atomic64_t functions at boot or
2195 at module load time.
2199 config ASYNC_RAID6_TEST
2200 tristate "Self test for hardware accelerated raid6 recovery"
2201 depends on ASYNC_RAID6_RECOV
2204 This is a one-shot self test that permutes through the
2205 recovery of all the possible two disk failure scenarios for a
2206 N-disk array. Recovery is performed with the asynchronous
2207 raid6 recovery routines, and will optionally use an offload
2208 engine if one is available.
2213 tristate "Test functions located in the hexdump module at runtime"
2215 config STRING_SELFTEST
2216 tristate "Test string functions at runtime"
2218 config TEST_STRING_HELPERS
2219 tristate "Test functions located in the string_helpers module at runtime"
2222 tristate "Test strscpy*() family of functions at runtime"
2225 tristate "Test kstrto*() family of functions at runtime"
2228 tristate "Test printf() family of functions at runtime"
2231 tristate "Test scanf() family of functions at runtime"
2234 tristate "Test bitmap_*() family of functions at runtime"
2236 Enable this option to test the bitmap functions at boot.
2241 tristate "Test functions located in the uuid module at runtime"
2244 tristate "Test the XArray code at runtime"
2246 config TEST_RHASHTABLE
2247 tristate "Perform selftest on resizable hash table"
2249 Enable this option to test the rhashtable functions at boot.
2254 tristate "Perform selftest on siphash functions"
2256 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2257 functions on boot (or module load).
2259 This is intended to help people writing architecture-specific
2260 optimized versions. If unsure, say N.
2263 tristate "Perform selftest on IDA functions"
2266 tristate "Perform selftest on priority array manager"
2269 Enable this option to test priority array manager on boot
2274 config TEST_IRQ_TIMINGS
2275 bool "IRQ timings selftest"
2276 depends on IRQ_TIMINGS
2278 Enable this option to test the irq timings code on boot.
2283 tristate "Test module loading with 'hello world' module"
2286 This builds the "test_module" module that emits "Hello, world"
2287 on printk when loaded. It is designed to be used for basic
2288 evaluation of the module loading subsystem (for example when
2289 validating module verification). It lacks any extra dependencies,
2290 and will not normally be loaded by the system unless explicitly
2296 tristate "Test module for compilation of bitops operations"
2299 This builds the "test_bitops" module that is much like the
2300 TEST_LKM module except that it does a basic exercise of the
2301 set/clear_bit macros and get_count_order/long to make sure there are
2302 no compiler warnings from C=1 sparse checker or -Wextra
2303 compilations. It has no dependencies and doesn't run or load unless
2304 explicitly requested by name. for example: modprobe test_bitops.
2309 tristate "Test module for stress/performance analysis of vmalloc allocator"
2314 This builds the "test_vmalloc" module that should be used for
2315 stress and performance analysis. So, any new change for vmalloc
2316 subsystem can be evaluated from performance and stability point
2321 config TEST_USER_COPY
2322 tristate "Test user/kernel boundary protections"
2325 This builds the "test_user_copy" module that runs sanity checks
2326 on the copy_to/from_user infrastructure, making sure basic
2327 user/kernel boundary testing is working. If it fails to load,
2328 a regression has been detected in the user/kernel memory boundary
2334 tristate "Test BPF filter functionality"
2337 This builds the "test_bpf" module that runs various test vectors
2338 against the BPF interpreter or BPF JIT compiler depending on the
2339 current setting. This is in particular useful for BPF JIT compiler
2340 development, but also to run regression tests against changes in
2341 the interpreter code. It also enables test stubs for eBPF maps and
2342 verifier used by user space verifier testsuite.
2346 config TEST_BLACKHOLE_DEV
2347 tristate "Test blackhole netdev functionality"
2350 This builds the "test_blackhole_dev" module that validates the
2351 data path through this blackhole netdev.
2355 config FIND_BIT_BENCHMARK
2356 tristate "Test find_bit functions"
2358 This builds the "test_find_bit" module that measure find_*_bit()
2359 functions performance.
2363 config TEST_FIRMWARE
2364 tristate "Test firmware loading via userspace interface"
2365 depends on FW_LOADER
2367 This builds the "test_firmware" module that creates a userspace
2368 interface for testing firmware loading. This can be used to
2369 control the triggering of firmware loading without needing an
2370 actual firmware-using device. The contents can be rechecked by
2376 tristate "sysctl test driver"
2377 depends on PROC_SYSCTL
2379 This builds the "test_sysctl" module. This driver enables to test the
2380 proc sysctl interfaces available to drivers safely without affecting
2381 production knobs which might alter system functionality.
2385 config BITFIELD_KUNIT
2386 tristate "KUnit test bitfield functions at runtime"
2389 Enable this option to test the bitfield functions at boot.
2391 KUnit tests run during boot and output the results to the debug log
2392 in TAP format (http://testanything.org/). Only useful for kernel devs
2393 running the KUnit test harness, and not intended for inclusion into a
2396 For more information on KUnit and unit tests in general please refer
2397 to the KUnit documentation in Documentation/dev-tools/kunit/.
2401 config HASH_KUNIT_TEST
2402 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2404 default KUNIT_ALL_TESTS
2406 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2407 integer (<linux/hash.h>) hash functions on boot.
2409 KUnit tests run during boot and output the results to the debug log
2410 in TAP format (https://testanything.org/). Only useful for kernel devs
2411 running the KUnit test harness, and not intended for inclusion into a
2414 For more information on KUnit and unit tests in general please refer
2415 to the KUnit documentation in Documentation/dev-tools/kunit/.
2417 This is intended to help people writing architecture-specific
2418 optimized versions. If unsure, say N.
2420 config RESOURCE_KUNIT_TEST
2421 tristate "KUnit test for resource API"
2424 This builds the resource API unit test.
2425 Tests the logic of API provided by resource.c and ioport.h.
2426 For more information on KUnit and unit tests in general please refer
2427 to the KUnit documentation in Documentation/dev-tools/kunit/.
2431 config SYSCTL_KUNIT_TEST
2432 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2434 default KUNIT_ALL_TESTS
2436 This builds the proc sysctl unit test, which runs on boot.
2437 Tests the API contract and implementation correctness of sysctl.
2438 For more information on KUnit and unit tests in general please refer
2439 to the KUnit documentation in Documentation/dev-tools/kunit/.
2443 config LIST_KUNIT_TEST
2444 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2446 default KUNIT_ALL_TESTS
2448 This builds the linked list KUnit test suite.
2449 It tests that the API and basic functionality of the list_head type
2450 and associated macros.
2452 KUnit tests run during boot and output the results to the debug log
2453 in TAP format (https://testanything.org/). Only useful for kernel devs
2454 running the KUnit test harness, and not intended for inclusion into a
2457 For more information on KUnit and unit tests in general please refer
2458 to the KUnit documentation in Documentation/dev-tools/kunit/.
2462 config LINEAR_RANGES_TEST
2463 tristate "KUnit test for linear_ranges"
2465 select LINEAR_RANGES
2467 This builds the linear_ranges unit test, which runs on boot.
2468 Tests the linear_ranges logic correctness.
2469 For more information on KUnit and unit tests in general please refer
2470 to the KUnit documentation in Documentation/dev-tools/kunit/.
2474 config CMDLINE_KUNIT_TEST
2475 tristate "KUnit test for cmdline API"
2478 This builds the cmdline API unit test.
2479 Tests the logic of API provided by cmdline.c.
2480 For more information on KUnit and unit tests in general please refer
2481 to the KUnit documentation in Documentation/dev-tools/kunit/.
2486 tristate "KUnit test for bits.h"
2489 This builds the bits unit test.
2490 Tests the logic of macros defined in bits.h.
2491 For more information on KUnit and unit tests in general please refer
2492 to the KUnit documentation in Documentation/dev-tools/kunit/.
2496 config SLUB_KUNIT_TEST
2497 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2498 depends on SLUB_DEBUG && KUNIT
2499 default KUNIT_ALL_TESTS
2501 This builds SLUB allocator unit test.
2502 Tests SLUB cache debugging functionality.
2503 For more information on KUnit and unit tests in general please refer
2504 to the KUnit documentation in Documentation/dev-tools/kunit/.
2508 config RATIONAL_KUNIT_TEST
2509 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2510 depends on KUNIT && RATIONAL
2511 default KUNIT_ALL_TESTS
2513 This builds the rational math unit test.
2514 For more information on KUnit and unit tests in general please refer
2515 to the KUnit documentation in Documentation/dev-tools/kunit/.
2519 config MEMCPY_KUNIT_TEST
2520 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2522 default KUNIT_ALL_TESTS
2524 Builds unit tests for memcpy(), memmove(), and memset() functions.
2525 For more information on KUnit and unit tests in general please refer
2526 to the KUnit documentation in Documentation/dev-tools/kunit/.
2530 config OVERFLOW_KUNIT_TEST
2531 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2533 default KUNIT_ALL_TESTS
2535 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2538 For more information on KUnit and unit tests in general please refer
2539 to the KUnit documentation in Documentation/dev-tools/kunit/.
2543 config STACKINIT_KUNIT_TEST
2544 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2546 default KUNIT_ALL_TESTS
2548 Test if the kernel is zero-initializing stack variables and
2549 padding. Coverage is controlled by compiler flags,
2550 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2551 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2552 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2555 tristate "udelay test driver"
2557 This builds the "udelay_test" module that helps to make sure
2558 that udelay() is working properly.
2562 config TEST_STATIC_KEYS
2563 tristate "Test static keys"
2566 Test the static key interfaces.
2571 tristate "kmod stress tester"
2573 depends on NETDEVICES && NET_CORE && INET # for TUN
2575 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2581 Test the kernel's module loading mechanism: kmod. kmod implements
2582 support to load modules using the Linux kernel's usermode helper.
2583 This test provides a series of tests against kmod.
2585 Although technically you can either build test_kmod as a module or
2586 into the kernel we disallow building it into the kernel since
2587 it stress tests request_module() and this will very likely cause
2588 some issues by taking over precious threads available from other
2589 module load requests, ultimately this could be fatal.
2593 tools/testing/selftests/kmod/kmod.sh --help
2597 config TEST_DEBUG_VIRTUAL
2598 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2599 depends on DEBUG_VIRTUAL
2601 Test the kernel's ability to detect incorrect calls to
2602 virt_to_phys() done against the non-linear part of the
2603 kernel's virtual address map.
2607 config TEST_MEMCAT_P
2608 tristate "Test memcat_p() helper function"
2610 Test the memcat_p() helper for correctly merging two
2611 pointer arrays together.
2615 config TEST_LIVEPATCH
2616 tristate "Test livepatching"
2618 depends on DYNAMIC_DEBUG
2619 depends on LIVEPATCH
2622 Test kernel livepatching features for correctness. The tests will
2623 load test modules that will be livepatched in various scenarios.
2625 To run all the livepatching tests:
2627 make -C tools/testing/selftests TARGETS=livepatch run_tests
2629 Alternatively, individual tests may be invoked:
2631 tools/testing/selftests/livepatch/test-callbacks.sh
2632 tools/testing/selftests/livepatch/test-livepatch.sh
2633 tools/testing/selftests/livepatch/test-shadow-vars.sh
2638 tristate "Perform selftest on object aggreration manager"
2642 Enable this option to test object aggregation manager on boot
2646 tristate "Test heap/page initialization"
2648 Test if the kernel is zero-initializing heap and page allocations.
2649 This can be useful to test init_on_alloc and init_on_free features.
2654 tristate "Test HMM (Heterogeneous Memory Management)"
2655 depends on TRANSPARENT_HUGEPAGE
2656 depends on DEVICE_PRIVATE
2660 This is a pseudo device driver solely for testing HMM.
2661 Say M here if you want to build the HMM test module.
2662 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2666 config TEST_FREE_PAGES
2667 tristate "Test freeing pages"
2669 Test that a memory leak does not occur due to a race between
2670 freeing a block of pages and a speculative page reference.
2671 Loading this module is safe if your kernel has the bug fixed.
2672 If the bug is not fixed, it will leak gigabytes of memory and
2673 probably OOM your system.
2676 tristate "Test floating point operations in kernel space"
2677 depends on X86 && !KCOV_INSTRUMENT_ALL
2679 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2680 which will trigger a sequence of floating point operations. This is used
2681 for self-testing floating point control register setting in
2686 config TEST_CLOCKSOURCE_WATCHDOG
2687 tristate "Test clocksource watchdog in kernel space"
2688 depends on CLOCKSOURCE_WATCHDOG
2690 Enable this option to create a kernel module that will trigger
2691 a test of the clocksource watchdog. This module may be loaded
2692 via modprobe or insmod in which case it will run upon being
2693 loaded, or it may be built in, in which case it will run
2698 endif # RUNTIME_TESTING_MENU
2700 config ARCH_USE_MEMTEST
2703 An architecture should select this when it uses early_memtest()
2704 during boot process.
2708 depends on ARCH_USE_MEMTEST
2710 This option adds a kernel parameter 'memtest', which allows memtest
2711 to be set and executed.
2712 memtest=0, mean disabled; -- default
2713 memtest=1, mean do 1 test pattern;
2715 memtest=17, mean do 17 test patterns.
2716 If you are unsure how to answer this question, answer N.
2720 config HYPERV_TESTING
2721 bool "Microsoft Hyper-V driver testing"
2723 depends on HYPERV && DEBUG_FS
2725 Select this option to enable Hyper-V vmbus testing.
2727 endmenu # "Kernel Testing and Coverage"
2729 source "Documentation/Kconfig"
2731 endmenu # Kernel hacking
projects / linux-2.6-microblaze.git / blob