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
702 bool "Debug slab memory allocations"
703 depends on DEBUG_KERNEL && SLAB
705 Say Y here to have the kernel do limited verification on memory
706 allocation as well as poisoning memory on free to catch use of freed
707 memory. This can make kmalloc/kfree-intensive workloads much slower.
710 bool "SLUB debugging on by default"
711 depends on SLUB && SLUB_DEBUG
714 Boot with debugging on by default. SLUB boots by default with
715 the runtime debug capabilities switched off. Enabling this is
716 equivalent to specifying the "slub_debug" parameter on boot.
717 There is no support for more fine grained debug control like
718 possible with slub_debug=xxx. SLUB debugging may be switched
719 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
724 bool "Enable SLUB performance statistics"
725 depends on SLUB && SYSFS
727 SLUB statistics are useful to debug SLUBs allocation behavior in
728 order find ways to optimize the allocator. This should never be
729 enabled for production use since keeping statistics slows down
730 the allocator by a few percentage points. The slabinfo command
731 supports the determination of the most active slabs to figure
732 out which slabs are relevant to a particular load.
733 Try running: slabinfo -DA
735 config HAVE_DEBUG_KMEMLEAK
738 config DEBUG_KMEMLEAK
739 bool "Kernel memory leak detector"
740 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
742 select STACKTRACE if STACKTRACE_SUPPORT
746 Say Y here if you want to enable the memory leak
747 detector. The memory allocation/freeing is traced in a way
748 similar to the Boehm's conservative garbage collector, the
749 difference being that the orphan objects are not freed but
750 only shown in /sys/kernel/debug/kmemleak. Enabling this
751 feature will introduce an overhead to memory
752 allocations. See Documentation/dev-tools/kmemleak.rst for more
755 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
756 of finding leaks due to the slab objects poisoning.
758 In order to access the kmemleak file, debugfs needs to be
759 mounted (usually at /sys/kernel/debug).
761 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
762 int "Kmemleak memory pool size"
763 depends on DEBUG_KMEMLEAK
767 Kmemleak must track all the memory allocations to avoid
768 reporting false positives. Since memory may be allocated or
769 freed before kmemleak is fully initialised, use a static pool
770 of metadata objects to track such callbacks. After kmemleak is
771 fully initialised, this memory pool acts as an emergency one
772 if slab allocations fail.
774 config DEBUG_KMEMLEAK_TEST
775 tristate "Simple test for the kernel memory leak detector"
776 depends on DEBUG_KMEMLEAK && m
778 This option enables a module that explicitly leaks memory.
782 config DEBUG_KMEMLEAK_DEFAULT_OFF
783 bool "Default kmemleak to off"
784 depends on DEBUG_KMEMLEAK
786 Say Y here to disable kmemleak by default. It can then be enabled
787 on the command line via kmemleak=on.
789 config DEBUG_KMEMLEAK_AUTO_SCAN
790 bool "Enable kmemleak auto scan thread on boot up"
792 depends on DEBUG_KMEMLEAK
794 Depending on the cpu, kmemleak scan may be cpu intensive and can
795 stall user tasks at times. This option enables/disables automatic
796 kmemleak scan at boot up.
798 Say N here to disable kmemleak auto scan thread to stop automatic
799 scanning. Disabling this option disables automatic reporting of
804 config DEBUG_STACK_USAGE
805 bool "Stack utilization instrumentation"
806 depends on DEBUG_KERNEL && !IA64
808 Enables the display of the minimum amount of free stack which each
809 task has ever had available in the sysrq-T and sysrq-P debug output.
811 This option will slow down process creation somewhat.
813 config SCHED_STACK_END_CHECK
814 bool "Detect stack corruption on calls to schedule()"
815 depends on DEBUG_KERNEL
818 This option checks for a stack overrun on calls to schedule().
819 If the stack end location is found to be over written always panic as
820 the content of the corrupted region can no longer be trusted.
821 This is to ensure no erroneous behaviour occurs which could result in
822 data corruption or a sporadic crash at a later stage once the region
823 is examined. The runtime overhead introduced is minimal.
825 config ARCH_HAS_DEBUG_VM_PGTABLE
828 An architecture should select this when it can successfully
829 build and run DEBUG_VM_PGTABLE.
833 depends on DEBUG_KERNEL
835 Enable this to turn on extended checks in the virtual-memory system
836 that may impact performance.
840 config DEBUG_VM_VMACACHE
841 bool "Debug VMA caching"
844 Enable this to turn on VMA caching debug information. Doing so
845 can cause significant overhead, so only enable it in non-production
851 bool "Debug VM red-black trees"
854 Enable VM red-black tree debugging information and extra validations.
858 config DEBUG_VM_PGFLAGS
859 bool "Debug page-flags operations"
862 Enables extra validation on page flags operations.
866 config DEBUG_VM_PGTABLE
867 bool "Debug arch page table for semantics compliance"
869 depends on ARCH_HAS_DEBUG_VM_PGTABLE
870 default y if DEBUG_VM
872 This option provides a debug method which can be used to test
873 architecture page table helper functions on various platforms in
874 verifying if they comply with expected generic MM semantics. This
875 will help architecture code in making sure that any changes or
876 new additions of these helpers still conform to expected
877 semantics of the generic MM. Platforms will have to opt in for
878 this through ARCH_HAS_DEBUG_VM_PGTABLE.
882 config ARCH_HAS_DEBUG_VIRTUAL
886 bool "Debug VM translations"
887 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
889 Enable some costly sanity checks in virtual to page code. This can
890 catch mistakes with virt_to_page() and friends.
894 config DEBUG_NOMMU_REGIONS
895 bool "Debug the global anon/private NOMMU mapping region tree"
896 depends on DEBUG_KERNEL && !MMU
898 This option causes the global tree of anonymous and private mapping
899 regions to be regularly checked for invalid topology.
901 config DEBUG_MEMORY_INIT
902 bool "Debug memory initialisation" if EXPERT
905 Enable this for additional checks during memory initialisation.
906 The sanity checks verify aspects of the VM such as the memory model
907 and other information provided by the architecture. Verbose
908 information will be printed at KERN_DEBUG loglevel depending
909 on the mminit_loglevel= command-line option.
913 config MEMORY_NOTIFIER_ERROR_INJECT
914 tristate "Memory hotplug notifier error injection module"
915 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
917 This option provides the ability to inject artificial errors to
918 memory hotplug notifier chain callbacks. It is controlled through
919 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
921 If the notifier call chain should be failed with some events
922 notified, write the error code to "actions/<notifier event>/error".
924 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
926 # cd /sys/kernel/debug/notifier-error-inject/memory
927 # echo -12 > actions/MEM_GOING_OFFLINE/error
928 # echo offline > /sys/devices/system/memory/memoryXXX/state
929 bash: echo: write error: Cannot allocate memory
931 To compile this code as a module, choose M here: the module will
932 be called memory-notifier-error-inject.
936 config DEBUG_PER_CPU_MAPS
937 bool "Debug access to per_cpu maps"
938 depends on DEBUG_KERNEL
941 Say Y to verify that the per_cpu map being accessed has
942 been set up. This adds a fair amount of code to kernel memory
943 and decreases performance.
947 config DEBUG_KMAP_LOCAL
948 bool "Debug kmap_local temporary mappings"
949 depends on DEBUG_KERNEL && KMAP_LOCAL
951 This option enables additional error checking for the kmap_local
952 infrastructure. Disable for production use.
954 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
957 config DEBUG_KMAP_LOCAL_FORCE_MAP
958 bool "Enforce kmap_local temporary mappings"
959 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
961 select DEBUG_KMAP_LOCAL
963 This option enforces temporary mappings through the kmap_local
964 mechanism for non-highmem pages and on non-highmem systems.
965 Disable this for production systems!
968 bool "Highmem debugging"
969 depends on DEBUG_KERNEL && HIGHMEM
970 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
971 select DEBUG_KMAP_LOCAL
973 This option enables additional error checking for high memory
974 systems. Disable for production systems.
976 config HAVE_DEBUG_STACKOVERFLOW
979 config DEBUG_STACKOVERFLOW
980 bool "Check for stack overflows"
981 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
983 Say Y here if you want to check for overflows of kernel, IRQ
984 and exception stacks (if your architecture uses them). This
985 option will show detailed messages if free stack space drops
986 below a certain limit.
988 These kinds of bugs usually occur when call-chains in the
989 kernel get too deep, especially when interrupts are
992 Use this in cases where you see apparently random memory
993 corruption, especially if it appears in 'struct thread_info'
995 If in doubt, say "N".
997 source "lib/Kconfig.kasan"
998 source "lib/Kconfig.kfence"
1000 endmenu # "Memory Debugging"
1003 bool "Debug shared IRQ handlers"
1004 depends on DEBUG_KERNEL
1006 Enable this to generate a spurious interrupt just before a shared
1007 interrupt handler is deregistered (generating one when registering
1008 is currently disabled). Drivers need to handle this correctly. Some
1009 don't and need to be caught.
1011 menu "Debug Oops, Lockups and Hangs"
1013 config PANIC_ON_OOPS
1014 bool "Panic on Oops"
1016 Say Y here to enable the kernel to panic when it oopses. This
1017 has the same effect as setting oops=panic on the kernel command
1020 This feature is useful to ensure that the kernel does not do
1021 anything erroneous after an oops which could result in data
1022 corruption or other issues.
1026 config PANIC_ON_OOPS_VALUE
1029 default 0 if !PANIC_ON_OOPS
1030 default 1 if PANIC_ON_OOPS
1032 config PANIC_TIMEOUT
1036 Set the timeout value (in seconds) until a reboot occurs when
1037 the kernel panics. If n = 0, then we wait forever. A timeout
1038 value n > 0 will wait n seconds before rebooting, while a timeout
1039 value n < 0 will reboot immediately.
1041 config LOCKUP_DETECTOR
1044 config SOFTLOCKUP_DETECTOR
1045 bool "Detect Soft Lockups"
1046 depends on DEBUG_KERNEL && !S390
1047 select LOCKUP_DETECTOR
1049 Say Y here to enable the kernel to act as a watchdog to detect
1052 Softlockups are bugs that cause the kernel to loop in kernel
1053 mode for more than 20 seconds, without giving other tasks a
1054 chance to run. The current stack trace is displayed upon
1055 detection and the system will stay locked up.
1057 config BOOTPARAM_SOFTLOCKUP_PANIC
1058 bool "Panic (Reboot) On Soft Lockups"
1059 depends on SOFTLOCKUP_DETECTOR
1061 Say Y here to enable the kernel to panic on "soft lockups",
1062 which are bugs that cause the kernel to loop in kernel
1063 mode for more than 20 seconds (configurable using the watchdog_thresh
1064 sysctl), without giving other tasks a chance to run.
1066 The panic can be used in combination with panic_timeout,
1067 to cause the system to reboot automatically after a
1068 lockup has been detected. This feature is useful for
1069 high-availability systems that have uptime guarantees and
1070 where a lockup must be resolved ASAP.
1074 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
1076 depends on SOFTLOCKUP_DETECTOR
1078 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
1079 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
1081 config HARDLOCKUP_DETECTOR_PERF
1083 select SOFTLOCKUP_DETECTOR
1086 # Enables a timestamp based low pass filter to compensate for perf based
1087 # hard lockup detection which runs too fast due to turbo modes.
1089 config HARDLOCKUP_CHECK_TIMESTAMP
1093 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1094 # lockup detector rather than the perf based detector.
1096 config HARDLOCKUP_DETECTOR
1097 bool "Detect Hard Lockups"
1098 depends on DEBUG_KERNEL && !S390
1099 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1100 select LOCKUP_DETECTOR
1101 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1103 Say Y here to enable the kernel to act as a watchdog to detect
1106 Hardlockups are bugs that cause the CPU to loop in kernel mode
1107 for more than 10 seconds, without letting other interrupts have a
1108 chance to run. The current stack trace is displayed upon detection
1109 and the system will stay locked up.
1111 config BOOTPARAM_HARDLOCKUP_PANIC
1112 bool "Panic (Reboot) On Hard Lockups"
1113 depends on HARDLOCKUP_DETECTOR
1115 Say Y here to enable the kernel to panic on "hard lockups",
1116 which are bugs that cause the kernel to loop in kernel
1117 mode with interrupts disabled for more than 10 seconds (configurable
1118 using the watchdog_thresh sysctl).
1122 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
1124 depends on HARDLOCKUP_DETECTOR
1126 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
1127 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
1129 config DETECT_HUNG_TASK
1130 bool "Detect Hung Tasks"
1131 depends on DEBUG_KERNEL
1132 default SOFTLOCKUP_DETECTOR
1134 Say Y here to enable the kernel to detect "hung tasks",
1135 which are bugs that cause the task to be stuck in
1136 uninterruptible "D" state indefinitely.
1138 When a hung task is detected, the kernel will print the
1139 current stack trace (which you should report), but the
1140 task will stay in uninterruptible state. If lockdep is
1141 enabled then all held locks will also be reported. This
1142 feature has negligible overhead.
1144 config DEFAULT_HUNG_TASK_TIMEOUT
1145 int "Default timeout for hung task detection (in seconds)"
1146 depends on DETECT_HUNG_TASK
1149 This option controls the default timeout (in seconds) used
1150 to determine when a task has become non-responsive and should
1153 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1154 sysctl or by writing a value to
1155 /proc/sys/kernel/hung_task_timeout_secs.
1157 A timeout of 0 disables the check. The default is two minutes.
1158 Keeping the default should be fine in most cases.
1160 config BOOTPARAM_HUNG_TASK_PANIC
1161 bool "Panic (Reboot) On Hung Tasks"
1162 depends on DETECT_HUNG_TASK
1164 Say Y here to enable the kernel to panic on "hung tasks",
1165 which are bugs that cause the kernel to leave a task stuck
1166 in uninterruptible "D" state.
1168 The panic can be used in combination with panic_timeout,
1169 to cause the system to reboot automatically after a
1170 hung task has been detected. This feature is useful for
1171 high-availability systems that have uptime guarantees and
1172 where a hung tasks must be resolved ASAP.
1176 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
1178 depends on DETECT_HUNG_TASK
1180 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
1181 default 1 if BOOTPARAM_HUNG_TASK_PANIC
1184 bool "Detect Workqueue Stalls"
1185 depends on DEBUG_KERNEL
1187 Say Y here to enable stall detection on workqueues. If a
1188 worker pool doesn't make forward progress on a pending work
1189 item for over a given amount of time, 30s by default, a
1190 warning message is printed along with dump of workqueue
1191 state. This can be configured through kernel parameter
1192 "workqueue.watchdog_thresh" and its sysfs counterpart.
1195 tristate "Test module to generate lockups"
1198 This builds the "test_lockup" module that helps to make sure
1199 that watchdogs and lockup detectors are working properly.
1201 Depending on module parameters it could emulate soft or hard
1202 lockup, "hung task", or locking arbitrary lock for a long time.
1203 Also it could generate series of lockups with cooling-down periods.
1207 endmenu # "Debug lockups and hangs"
1209 menu "Scheduler Debugging"
1212 bool "Collect scheduler debugging info"
1213 depends on DEBUG_KERNEL && PROC_FS
1216 If you say Y here, the /proc/sched_debug file will be provided
1217 that can help debug the scheduler. The runtime overhead of this
1225 bool "Collect scheduler statistics"
1226 depends on DEBUG_KERNEL && PROC_FS
1229 If you say Y here, additional code will be inserted into the
1230 scheduler and related routines to collect statistics about
1231 scheduler behavior and provide them in /proc/schedstat. These
1232 stats may be useful for both tuning and debugging the scheduler
1233 If you aren't debugging the scheduler or trying to tune a specific
1234 application, you can say N to avoid the very slight overhead
1239 config DEBUG_TIMEKEEPING
1240 bool "Enable extra timekeeping sanity checking"
1242 This option will enable additional timekeeping sanity checks
1243 which may be helpful when diagnosing issues where timekeeping
1244 problems are suspected.
1246 This may include checks in the timekeeping hotpaths, so this
1247 option may have a (very small) performance impact to some
1252 config DEBUG_PREEMPT
1253 bool "Debug preemptible kernel"
1254 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1257 If you say Y here then the kernel will use a debug variant of the
1258 commonly used smp_processor_id() function and will print warnings
1259 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1260 will detect preemption count underflows.
1262 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1264 config LOCK_DEBUGGING_SUPPORT
1266 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1269 config PROVE_LOCKING
1270 bool "Lock debugging: prove locking correctness"
1271 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1273 select DEBUG_SPINLOCK
1274 select DEBUG_MUTEXES if !PREEMPT_RT
1275 select DEBUG_RT_MUTEXES if RT_MUTEXES
1277 select DEBUG_WW_MUTEX_SLOWPATH
1278 select DEBUG_LOCK_ALLOC
1279 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1280 select TRACE_IRQFLAGS
1283 This feature enables the kernel to prove that all locking
1284 that occurs in the kernel runtime is mathematically
1285 correct: that under no circumstance could an arbitrary (and
1286 not yet triggered) combination of observed locking
1287 sequences (on an arbitrary number of CPUs, running an
1288 arbitrary number of tasks and interrupt contexts) cause a
1291 In short, this feature enables the kernel to report locking
1292 related deadlocks before they actually occur.
1294 The proof does not depend on how hard and complex a
1295 deadlock scenario would be to trigger: how many
1296 participant CPUs, tasks and irq-contexts would be needed
1297 for it to trigger. The proof also does not depend on
1298 timing: if a race and a resulting deadlock is possible
1299 theoretically (no matter how unlikely the race scenario
1300 is), it will be proven so and will immediately be
1301 reported by the kernel (once the event is observed that
1302 makes the deadlock theoretically possible).
1304 If a deadlock is impossible (i.e. the locking rules, as
1305 observed by the kernel, are mathematically correct), the
1306 kernel reports nothing.
1308 NOTE: this feature can also be enabled for rwlocks, mutexes
1309 and rwsems - in which case all dependencies between these
1310 different locking variants are observed and mapped too, and
1311 the proof of observed correctness is also maintained for an
1312 arbitrary combination of these separate locking variants.
1314 For more details, see Documentation/locking/lockdep-design.rst.
1316 config PROVE_RAW_LOCK_NESTING
1317 bool "Enable raw_spinlock - spinlock nesting checks"
1318 depends on PROVE_LOCKING
1321 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1322 that the lock nesting rules for PREEMPT_RT enabled kernels are
1325 NOTE: There are known nesting problems. So if you enable this
1326 option expect lockdep splats until these problems have been fully
1327 addressed which is work in progress. This config switch allows to
1328 identify and analyze these problems. It will be removed and the
1329 check permanently enabled once the main issues have been fixed.
1331 If unsure, select N.
1334 bool "Lock usage statistics"
1335 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1337 select DEBUG_SPINLOCK
1338 select DEBUG_MUTEXES if !PREEMPT_RT
1339 select DEBUG_RT_MUTEXES if RT_MUTEXES
1340 select DEBUG_LOCK_ALLOC
1343 This feature enables tracking lock contention points
1345 For more details, see Documentation/locking/lockstat.rst
1347 This also enables lock events required by "perf lock",
1349 If you want to use "perf lock", you also need to turn on
1350 CONFIG_EVENT_TRACING.
1352 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1353 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1355 config DEBUG_RT_MUTEXES
1356 bool "RT Mutex debugging, deadlock detection"
1357 depends on DEBUG_KERNEL && RT_MUTEXES
1359 This allows rt mutex semantics violations and rt mutex related
1360 deadlocks (lockups) to be detected and reported automatically.
1362 config DEBUG_SPINLOCK
1363 bool "Spinlock and rw-lock debugging: basic checks"
1364 depends on DEBUG_KERNEL
1365 select UNINLINE_SPIN_UNLOCK
1367 Say Y here and build SMP to catch missing spinlock initialization
1368 and certain other kinds of spinlock errors commonly made. This is
1369 best used in conjunction with the NMI watchdog so that spinlock
1370 deadlocks are also debuggable.
1372 config DEBUG_MUTEXES
1373 bool "Mutex debugging: basic checks"
1374 depends on DEBUG_KERNEL && !PREEMPT_RT
1376 This feature allows mutex semantics violations to be detected and
1379 config DEBUG_WW_MUTEX_SLOWPATH
1380 bool "Wait/wound mutex debugging: Slowpath testing"
1381 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1382 select DEBUG_LOCK_ALLOC
1383 select DEBUG_SPINLOCK
1384 select DEBUG_MUTEXES if !PREEMPT_RT
1385 select DEBUG_RT_MUTEXES if PREEMPT_RT
1387 This feature enables slowpath testing for w/w mutex users by
1388 injecting additional -EDEADLK wound/backoff cases. Together with
1389 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1390 will test all possible w/w mutex interface abuse with the
1391 exception of simply not acquiring all the required locks.
1392 Note that this feature can introduce significant overhead, so
1393 it really should not be enabled in a production or distro kernel,
1394 even a debug kernel. If you are a driver writer, enable it. If
1395 you are a distro, do not.
1398 bool "RW Semaphore debugging: basic checks"
1399 depends on DEBUG_KERNEL
1401 This debugging feature allows mismatched rw semaphore locks
1402 and unlocks to be detected and reported.
1404 config DEBUG_LOCK_ALLOC
1405 bool "Lock debugging: detect incorrect freeing of live locks"
1406 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1407 select DEBUG_SPINLOCK
1408 select DEBUG_MUTEXES if !PREEMPT_RT
1409 select DEBUG_RT_MUTEXES if RT_MUTEXES
1412 This feature will check whether any held lock (spinlock, rwlock,
1413 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1414 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1415 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1416 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1417 held during task exit.
1421 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1426 config LOCKDEP_SMALL
1430 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1431 depends on LOCKDEP && !LOCKDEP_SMALL
1435 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1437 config LOCKDEP_CHAINS_BITS
1438 int "Bitsize for MAX_LOCKDEP_CHAINS"
1439 depends on LOCKDEP && !LOCKDEP_SMALL
1443 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1445 config LOCKDEP_STACK_TRACE_BITS
1446 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1447 depends on LOCKDEP && !LOCKDEP_SMALL
1451 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1453 config LOCKDEP_STACK_TRACE_HASH_BITS
1454 int "Bitsize for STACK_TRACE_HASH_SIZE"
1455 depends on LOCKDEP && !LOCKDEP_SMALL
1459 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1461 config LOCKDEP_CIRCULAR_QUEUE_BITS
1462 int "Bitsize for elements in circular_queue struct"
1467 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1469 config DEBUG_LOCKDEP
1470 bool "Lock dependency engine debugging"
1471 depends on DEBUG_KERNEL && LOCKDEP
1472 select DEBUG_IRQFLAGS
1474 If you say Y here, the lock dependency engine will do
1475 additional runtime checks to debug itself, at the price
1476 of more runtime overhead.
1478 config DEBUG_ATOMIC_SLEEP
1479 bool "Sleep inside atomic section checking"
1480 select PREEMPT_COUNT
1481 depends on DEBUG_KERNEL
1482 depends on !ARCH_NO_PREEMPT
1484 If you say Y here, various routines which may sleep will become very
1485 noisy if they are called inside atomic sections: when a spinlock is
1486 held, inside an rcu read side critical section, inside preempt disabled
1487 sections, inside an interrupt, etc...
1489 config DEBUG_LOCKING_API_SELFTESTS
1490 bool "Locking API boot-time self-tests"
1491 depends on DEBUG_KERNEL
1493 Say Y here if you want the kernel to run a short self-test during
1494 bootup. The self-test checks whether common types of locking bugs
1495 are detected by debugging mechanisms or not. (if you disable
1496 lock debugging then those bugs won't be detected of course.)
1497 The following locking APIs are covered: spinlocks, rwlocks,
1500 config LOCK_TORTURE_TEST
1501 tristate "torture tests for locking"
1502 depends on DEBUG_KERNEL
1505 This option provides a kernel module that runs torture tests
1506 on kernel locking primitives. The kernel module may be built
1507 after the fact on the running kernel to be tested, if desired.
1509 Say Y here if you want kernel locking-primitive torture tests
1510 to be built into the kernel.
1511 Say M if you want these torture tests to build as a module.
1512 Say N if you are unsure.
1514 config WW_MUTEX_SELFTEST
1515 tristate "Wait/wound mutex selftests"
1517 This option provides a kernel module that runs tests on the
1518 on the struct ww_mutex locking API.
1520 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1521 with this test harness.
1523 Say M if you want these self tests to build as a module.
1524 Say N if you are unsure.
1526 config SCF_TORTURE_TEST
1527 tristate "torture tests for smp_call_function*()"
1528 depends on DEBUG_KERNEL
1531 This option provides a kernel module that runs torture tests
1532 on the smp_call_function() family of primitives. The kernel
1533 module may be built after the fact on the running kernel to
1534 be tested, if desired.
1536 config CSD_LOCK_WAIT_DEBUG
1537 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1538 depends on DEBUG_KERNEL
1542 This option enables debug prints when CPUs are slow to respond
1543 to the smp_call_function*() IPI wrappers. These debug prints
1544 include the IPI handler function currently executing (if any)
1545 and relevant stack traces.
1548 prompt "Lock debugging: prove subsystem device_lock() correctness"
1549 depends on PROVE_LOCKING
1551 For subsystems that have instrumented their usage of the device_lock()
1552 with nested annotations, enable lock dependency checking. The locking
1553 hierarchy 'subclass' identifiers are not compatible across
1554 sub-systems, so only one can be enabled at a time.
1556 config PROVE_NVDIMM_LOCKING
1558 depends on LIBNVDIMM
1560 Enable lockdep to validate nd_device_lock() usage.
1562 config PROVE_CXL_LOCKING
1566 Enable lockdep to validate cxl_device_lock() usage.
1570 endmenu # lock debugging
1572 config TRACE_IRQFLAGS
1573 depends on TRACE_IRQFLAGS_SUPPORT
1576 Enables hooks to interrupt enabling and disabling for
1577 either tracing or lock debugging.
1579 config TRACE_IRQFLAGS_NMI
1581 depends on TRACE_IRQFLAGS
1582 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1584 config DEBUG_IRQFLAGS
1585 bool "Debug IRQ flag manipulation"
1587 Enables checks for potentially unsafe enabling or disabling of
1588 interrupts, such as calling raw_local_irq_restore() when interrupts
1592 bool "Stack backtrace support"
1593 depends on STACKTRACE_SUPPORT
1595 This option causes the kernel to create a /proc/pid/stack for
1596 every process, showing its current stack trace.
1597 It is also used by various kernel debugging features that require
1598 stack trace generation.
1600 config WARN_ALL_UNSEEDED_RANDOM
1601 bool "Warn for all uses of unseeded randomness"
1604 Some parts of the kernel contain bugs relating to their use of
1605 cryptographically secure random numbers before it's actually possible
1606 to generate those numbers securely. This setting ensures that these
1607 flaws don't go unnoticed, by enabling a message, should this ever
1608 occur. This will allow people with obscure setups to know when things
1609 are going wrong, so that they might contact developers about fixing
1612 Unfortunately, on some models of some architectures getting
1613 a fully seeded CRNG is extremely difficult, and so this can
1614 result in dmesg getting spammed for a surprisingly long
1615 time. This is really bad from a security perspective, and
1616 so architecture maintainers really need to do what they can
1617 to get the CRNG seeded sooner after the system is booted.
1618 However, since users cannot do anything actionable to
1619 address this, by default this option is disabled.
1621 Say Y here if you want to receive warnings for all uses of
1622 unseeded randomness. This will be of use primarily for
1623 those developers interested in improving the security of
1624 Linux kernels running on their architecture (or
1627 config DEBUG_KOBJECT
1628 bool "kobject debugging"
1629 depends on DEBUG_KERNEL
1631 If you say Y here, some extra kobject debugging messages will be sent
1634 config DEBUG_KOBJECT_RELEASE
1635 bool "kobject release debugging"
1636 depends on DEBUG_OBJECTS_TIMERS
1638 kobjects are reference counted objects. This means that their
1639 last reference count put is not predictable, and the kobject can
1640 live on past the point at which a driver decides to drop it's
1641 initial reference to the kobject gained on allocation. An
1642 example of this would be a struct device which has just been
1645 However, some buggy drivers assume that after such an operation,
1646 the memory backing the kobject can be immediately freed. This
1647 goes completely against the principles of a refcounted object.
1649 If you say Y here, the kernel will delay the release of kobjects
1650 on the last reference count to improve the visibility of this
1651 kind of kobject release bug.
1653 config HAVE_DEBUG_BUGVERBOSE
1656 menu "Debug kernel data structures"
1659 bool "Debug linked list manipulation"
1660 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1662 Enable this to turn on extended checks in the linked-list
1668 bool "Debug priority linked list manipulation"
1669 depends on DEBUG_KERNEL
1671 Enable this to turn on extended checks in the priority-ordered
1672 linked-list (plist) walking routines. This checks the entire
1673 list multiple times during each manipulation.
1678 bool "Debug SG table operations"
1679 depends on DEBUG_KERNEL
1681 Enable this to turn on checks on scatter-gather tables. This can
1682 help find problems with drivers that do not properly initialize
1687 config DEBUG_NOTIFIERS
1688 bool "Debug notifier call chains"
1689 depends on DEBUG_KERNEL
1691 Enable this to turn on sanity checking for notifier call chains.
1692 This is most useful for kernel developers to make sure that
1693 modules properly unregister themselves from notifier chains.
1694 This is a relatively cheap check but if you care about maximum
1697 config BUG_ON_DATA_CORRUPTION
1698 bool "Trigger a BUG when data corruption is detected"
1701 Select this option if the kernel should BUG when it encounters
1702 data corruption in kernel memory structures when they get checked
1709 config DEBUG_CREDENTIALS
1710 bool "Debug credential management"
1711 depends on DEBUG_KERNEL
1713 Enable this to turn on some debug checking for credential
1714 management. The additional code keeps track of the number of
1715 pointers from task_structs to any given cred struct, and checks to
1716 see that this number never exceeds the usage count of the cred
1719 Furthermore, if SELinux is enabled, this also checks that the
1720 security pointer in the cred struct is never seen to be invalid.
1724 source "kernel/rcu/Kconfig.debug"
1726 config DEBUG_WQ_FORCE_RR_CPU
1727 bool "Force round-robin CPU selection for unbound work items"
1728 depends on DEBUG_KERNEL
1731 Workqueue used to implicitly guarantee that work items queued
1732 without explicit CPU specified are put on the local CPU. This
1733 guarantee is no longer true and while local CPU is still
1734 preferred work items may be put on foreign CPUs. Kernel
1735 parameter "workqueue.debug_force_rr_cpu" is added to force
1736 round-robin CPU selection to flush out usages which depend on the
1737 now broken guarantee. This config option enables the debug
1738 feature by default. When enabled, memory and cache locality will
1741 config CPU_HOTPLUG_STATE_CONTROL
1742 bool "Enable CPU hotplug state control"
1743 depends on DEBUG_KERNEL
1744 depends on HOTPLUG_CPU
1747 Allows to write steps between "offline" and "online" to the CPUs
1748 sysfs target file so states can be stepped granular. This is a debug
1749 option for now as the hotplug machinery cannot be stopped and
1750 restarted at arbitrary points yet.
1752 Say N if your are unsure.
1755 bool "Latency measuring infrastructure"
1756 depends on DEBUG_KERNEL
1757 depends on STACKTRACE_SUPPORT
1759 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1765 Enable this option if you want to use the LatencyTOP tool
1766 to find out which userspace is blocking on what kernel operations.
1768 source "kernel/trace/Kconfig"
1770 config PROVIDE_OHCI1394_DMA_INIT
1771 bool "Remote debugging over FireWire early on boot"
1772 depends on PCI && X86
1774 If you want to debug problems which hang or crash the kernel early
1775 on boot and the crashing machine has a FireWire port, you can use
1776 this feature to remotely access the memory of the crashed machine
1777 over FireWire. This employs remote DMA as part of the OHCI1394
1778 specification which is now the standard for FireWire controllers.
1780 With remote DMA, you can monitor the printk buffer remotely using
1781 firescope and access all memory below 4GB using fireproxy from gdb.
1782 Even controlling a kernel debugger is possible using remote DMA.
1786 If ohci1394_dma=early is used as boot parameter, it will initialize
1787 all OHCI1394 controllers which are found in the PCI config space.
1789 As all changes to the FireWire bus such as enabling and disabling
1790 devices cause a bus reset and thereby disable remote DMA for all
1791 devices, be sure to have the cable plugged and FireWire enabled on
1792 the debugging host before booting the debug target for debugging.
1794 This code (~1k) is freed after boot. By then, the firewire stack
1795 in charge of the OHCI-1394 controllers should be used instead.
1797 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1799 source "samples/Kconfig"
1801 config ARCH_HAS_DEVMEM_IS_ALLOWED
1804 config STRICT_DEVMEM
1805 bool "Filter access to /dev/mem"
1806 depends on MMU && DEVMEM
1807 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1808 default y if PPC || X86 || ARM64
1810 If this option is disabled, you allow userspace (root) access to all
1811 of memory, including kernel and userspace memory. Accidental
1812 access to this is obviously disastrous, but specific access can
1813 be used by people debugging the kernel. Note that with PAT support
1814 enabled, even in this case there are restrictions on /dev/mem
1815 use due to the cache aliasing requirements.
1817 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1818 file only allows userspace access to PCI space and the BIOS code and
1819 data regions. This is sufficient for dosemu and X and all common
1824 config IO_STRICT_DEVMEM
1825 bool "Filter I/O access to /dev/mem"
1826 depends on STRICT_DEVMEM
1828 If this option is disabled, you allow userspace (root) access to all
1829 io-memory regardless of whether a driver is actively using that
1830 range. Accidental access to this is obviously disastrous, but
1831 specific access can be used by people debugging kernel drivers.
1833 If this option is switched on, the /dev/mem file only allows
1834 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1835 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1836 if the driver using a given range cannot be disabled.
1840 menu "$(SRCARCH) Debugging"
1842 source "arch/$(SRCARCH)/Kconfig.debug"
1846 menu "Kernel Testing and Coverage"
1848 source "lib/kunit/Kconfig"
1850 config NOTIFIER_ERROR_INJECTION
1851 tristate "Notifier error injection"
1852 depends on DEBUG_KERNEL
1855 This option provides the ability to inject artificial errors to
1856 specified notifier chain callbacks. It is useful to test the error
1857 handling of notifier call chain failures.
1861 config PM_NOTIFIER_ERROR_INJECT
1862 tristate "PM notifier error injection module"
1863 depends on PM && NOTIFIER_ERROR_INJECTION
1864 default m if PM_DEBUG
1866 This option provides the ability to inject artificial errors to
1867 PM notifier chain callbacks. It is controlled through debugfs
1868 interface /sys/kernel/debug/notifier-error-inject/pm
1870 If the notifier call chain should be failed with some events
1871 notified, write the error code to "actions/<notifier event>/error".
1873 Example: Inject PM suspend error (-12 = -ENOMEM)
1875 # cd /sys/kernel/debug/notifier-error-inject/pm/
1876 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1877 # echo mem > /sys/power/state
1878 bash: echo: write error: Cannot allocate memory
1880 To compile this code as a module, choose M here: the module will
1881 be called pm-notifier-error-inject.
1885 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1886 tristate "OF reconfig notifier error injection module"
1887 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1889 This option provides the ability to inject artificial errors to
1890 OF reconfig notifier chain callbacks. It is controlled
1891 through debugfs interface under
1892 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1894 If the notifier call chain should be failed with some events
1895 notified, write the error code to "actions/<notifier event>/error".
1897 To compile this code as a module, choose M here: the module will
1898 be called of-reconfig-notifier-error-inject.
1902 config NETDEV_NOTIFIER_ERROR_INJECT
1903 tristate "Netdev notifier error injection module"
1904 depends on NET && NOTIFIER_ERROR_INJECTION
1906 This option provides the ability to inject artificial errors to
1907 netdevice notifier chain callbacks. It is controlled through debugfs
1908 interface /sys/kernel/debug/notifier-error-inject/netdev
1910 If the notifier call chain should be failed with some events
1911 notified, write the error code to "actions/<notifier event>/error".
1913 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1915 # cd /sys/kernel/debug/notifier-error-inject/netdev
1916 # echo -22 > actions/NETDEV_CHANGEMTU/error
1917 # ip link set eth0 mtu 1024
1918 RTNETLINK answers: Invalid argument
1920 To compile this code as a module, choose M here: the module will
1921 be called netdev-notifier-error-inject.
1925 config FUNCTION_ERROR_INJECTION
1927 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1929 config FAULT_INJECTION
1930 bool "Fault-injection framework"
1931 depends on DEBUG_KERNEL
1933 Provide fault-injection framework.
1934 For more details, see Documentation/fault-injection/.
1937 bool "Fault-injection capability for kmalloc"
1938 depends on FAULT_INJECTION
1939 depends on SLAB || SLUB
1941 Provide fault-injection capability for kmalloc.
1943 config FAIL_PAGE_ALLOC
1944 bool "Fault-injection capability for alloc_pages()"
1945 depends on FAULT_INJECTION
1947 Provide fault-injection capability for alloc_pages().
1949 config FAULT_INJECTION_USERCOPY
1950 bool "Fault injection capability for usercopy functions"
1951 depends on FAULT_INJECTION
1953 Provides fault-injection capability to inject failures
1954 in usercopy functions (copy_from_user(), get_user(), ...).
1956 config FAIL_MAKE_REQUEST
1957 bool "Fault-injection capability for disk IO"
1958 depends on FAULT_INJECTION && BLOCK
1960 Provide fault-injection capability for disk IO.
1962 config FAIL_IO_TIMEOUT
1963 bool "Fault-injection capability for faking disk interrupts"
1964 depends on FAULT_INJECTION && BLOCK
1966 Provide fault-injection capability on end IO handling. This
1967 will make the block layer "forget" an interrupt as configured,
1968 thus exercising the error handling.
1970 Only works with drivers that use the generic timeout handling,
1971 for others it won't do anything.
1974 bool "Fault-injection capability for futexes"
1976 depends on FAULT_INJECTION && FUTEX
1978 Provide fault-injection capability for futexes.
1980 config FAULT_INJECTION_DEBUG_FS
1981 bool "Debugfs entries for fault-injection capabilities"
1982 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1984 Enable configuration of fault-injection capabilities via debugfs.
1986 config FAIL_FUNCTION
1987 bool "Fault-injection capability for functions"
1988 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1990 Provide function-based fault-injection capability.
1991 This will allow you to override a specific function with a return
1992 with given return value. As a result, function caller will see
1993 an error value and have to handle it. This is useful to test the
1994 error handling in various subsystems.
1996 config FAIL_MMC_REQUEST
1997 bool "Fault-injection capability for MMC IO"
1998 depends on FAULT_INJECTION_DEBUG_FS && MMC
2000 Provide fault-injection capability for MMC IO.
2001 This will make the mmc core return data errors. This is
2002 useful to test the error handling in the mmc block device
2003 and to test how the mmc host driver handles retries from
2007 bool "Fault-injection capability for SunRPC"
2008 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2010 Provide fault-injection capability for SunRPC and
2013 config FAULT_INJECTION_STACKTRACE_FILTER
2014 bool "stacktrace filter for fault-injection capabilities"
2015 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
2018 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2020 Provide stacktrace filter for fault-injection capabilities
2022 config ARCH_HAS_KCOV
2025 An architecture should select this when it can successfully
2026 build and run with CONFIG_KCOV. This typically requires
2027 disabling instrumentation for some early boot code.
2029 config CC_HAS_SANCOV_TRACE_PC
2030 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2034 bool "Code coverage for fuzzing"
2035 depends on ARCH_HAS_KCOV
2036 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2037 depends on !ARCH_WANTS_NO_INSTR || STACK_VALIDATION || \
2038 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
2040 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2042 KCOV exposes kernel code coverage information in a form suitable
2043 for coverage-guided fuzzing (randomized testing).
2045 If RANDOMIZE_BASE is enabled, PC values will not be stable across
2046 different machines and across reboots. If you need stable PC values,
2047 disable RANDOMIZE_BASE.
2049 For more details, see Documentation/dev-tools/kcov.rst.
2051 config KCOV_ENABLE_COMPARISONS
2052 bool "Enable comparison operands collection by KCOV"
2054 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2056 KCOV also exposes operands of every comparison in the instrumented
2057 code along with operand sizes and PCs of the comparison instructions.
2058 These operands can be used by fuzzing engines to improve the quality
2059 of fuzzing coverage.
2061 config KCOV_INSTRUMENT_ALL
2062 bool "Instrument all code by default"
2066 If you are doing generic system call fuzzing (like e.g. syzkaller),
2067 then you will want to instrument the whole kernel and you should
2068 say y here. If you are doing more targeted fuzzing (like e.g.
2069 filesystem fuzzing with AFL) then you will want to enable coverage
2070 for more specific subsets of files, and should say n here.
2072 config KCOV_IRQ_AREA_SIZE
2073 hex "Size of interrupt coverage collection area in words"
2077 KCOV uses preallocated per-cpu areas to collect coverage from
2078 soft interrupts. This specifies the size of those areas in the
2079 number of unsigned long words.
2081 menuconfig RUNTIME_TESTING_MENU
2082 bool "Runtime Testing"
2085 if RUNTIME_TESTING_MENU
2088 tristate "Linux Kernel Dump Test Tool Module"
2091 This module enables testing of the different dumping mechanisms by
2092 inducing system failures at predefined crash points.
2093 If you don't need it: say N
2094 Choose M here to compile this code as a module. The module will be
2097 Documentation on how to use the module can be found in
2098 Documentation/fault-injection/provoke-crashes.rst
2100 config TEST_LIST_SORT
2101 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2103 default KUNIT_ALL_TESTS
2105 Enable this to turn on 'list_sort()' function test. This test is
2106 executed only once during system boot (so affects only boot time),
2107 or at module load time.
2111 config TEST_MIN_HEAP
2112 tristate "Min heap test"
2113 depends on DEBUG_KERNEL || m
2115 Enable this to turn on min heap function tests. This test is
2116 executed only once during system boot (so affects only boot time),
2117 or at module load time.
2122 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2124 default KUNIT_ALL_TESTS
2126 This option enables the self-test function of 'sort()' at boot,
2127 or at module load time.
2132 tristate "64bit/32bit division and modulo test"
2133 depends on DEBUG_KERNEL || m
2135 Enable this to turn on 'do_div()' function test. This test is
2136 executed only once during system boot (so affects only boot time),
2137 or at module load time.
2141 config KPROBES_SANITY_TEST
2142 tristate "Kprobes sanity tests"
2143 depends on DEBUG_KERNEL
2147 This option provides for testing basic kprobes functionality on
2148 boot. Samples of kprobe and kretprobe are inserted and
2149 verified for functionality.
2151 Say N if you are unsure.
2153 config FPROBE_SANITY_TEST
2154 bool "Self test for fprobe"
2155 depends on DEBUG_KERNEL
2159 This option will enable testing the fprobe when the system boot.
2160 A series of tests are made to verify that the fprobe is functioning
2163 Say N if you are unsure.
2165 config BACKTRACE_SELF_TEST
2166 tristate "Self test for the backtrace code"
2167 depends on DEBUG_KERNEL
2169 This option provides a kernel module that can be used to test
2170 the kernel stack backtrace code. This option is not useful
2171 for distributions or general kernels, but only for kernel
2172 developers working on architecture code.
2174 Note that if you want to also test saved backtraces, you will
2175 have to enable STACKTRACE as well.
2177 Say N if you are unsure.
2179 config TEST_REF_TRACKER
2180 tristate "Self test for reference tracker"
2181 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2184 This option provides a kernel module performing tests
2185 using reference tracker infrastructure.
2187 Say N if you are unsure.
2190 tristate "Red-Black tree test"
2191 depends on DEBUG_KERNEL
2193 A benchmark measuring the performance of the rbtree library.
2194 Also includes rbtree invariant checks.
2196 config REED_SOLOMON_TEST
2197 tristate "Reed-Solomon library test"
2198 depends on DEBUG_KERNEL || m
2200 select REED_SOLOMON_ENC16
2201 select REED_SOLOMON_DEC16
2203 This option enables the self-test function of rslib at boot,
2204 or at module load time.
2208 config INTERVAL_TREE_TEST
2209 tristate "Interval tree test"
2210 depends on DEBUG_KERNEL
2211 select INTERVAL_TREE
2213 A benchmark measuring the performance of the interval tree library
2216 tristate "Per cpu operations test"
2217 depends on m && DEBUG_KERNEL
2219 Enable this option to build test module which validates per-cpu
2224 config ATOMIC64_SELFTEST
2225 tristate "Perform an atomic64_t self-test"
2227 Enable this option to test the atomic64_t functions at boot or
2228 at module load time.
2232 config ASYNC_RAID6_TEST
2233 tristate "Self test for hardware accelerated raid6 recovery"
2234 depends on ASYNC_RAID6_RECOV
2237 This is a one-shot self test that permutes through the
2238 recovery of all the possible two disk failure scenarios for a
2239 N-disk array. Recovery is performed with the asynchronous
2240 raid6 recovery routines, and will optionally use an offload
2241 engine if one is available.
2246 tristate "Test functions located in the hexdump module at runtime"
2248 config STRING_SELFTEST
2249 tristate "Test string functions at runtime"
2251 config TEST_STRING_HELPERS
2252 tristate "Test functions located in the string_helpers module at runtime"
2255 tristate "Test strscpy*() family of functions at runtime"
2258 tristate "Test kstrto*() family of functions at runtime"
2261 tristate "Test printf() family of functions at runtime"
2264 tristate "Test scanf() family of functions at runtime"
2267 tristate "Test bitmap_*() family of functions at runtime"
2269 Enable this option to test the bitmap functions at boot.
2274 tristate "Test functions located in the uuid module at runtime"
2277 tristate "Test the XArray code at runtime"
2279 config TEST_RHASHTABLE
2280 tristate "Perform selftest on resizable hash table"
2282 Enable this option to test the rhashtable functions at boot.
2287 tristate "Perform selftest on siphash functions"
2289 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2290 functions on boot (or module load).
2292 This is intended to help people writing architecture-specific
2293 optimized versions. If unsure, say N.
2296 tristate "Perform selftest on IDA functions"
2299 tristate "Perform selftest on priority array manager"
2302 Enable this option to test priority array manager on boot
2307 config TEST_IRQ_TIMINGS
2308 bool "IRQ timings selftest"
2309 depends on IRQ_TIMINGS
2311 Enable this option to test the irq timings code on boot.
2316 tristate "Test module loading with 'hello world' module"
2319 This builds the "test_module" module that emits "Hello, world"
2320 on printk when loaded. It is designed to be used for basic
2321 evaluation of the module loading subsystem (for example when
2322 validating module verification). It lacks any extra dependencies,
2323 and will not normally be loaded by the system unless explicitly
2329 tristate "Test module for compilation of bitops operations"
2332 This builds the "test_bitops" module that is much like the
2333 TEST_LKM module except that it does a basic exercise of the
2334 set/clear_bit macros and get_count_order/long to make sure there are
2335 no compiler warnings from C=1 sparse checker or -Wextra
2336 compilations. It has no dependencies and doesn't run or load unless
2337 explicitly requested by name. for example: modprobe test_bitops.
2342 tristate "Test module for stress/performance analysis of vmalloc allocator"
2347 This builds the "test_vmalloc" module that should be used for
2348 stress and performance analysis. So, any new change for vmalloc
2349 subsystem can be evaluated from performance and stability point
2354 config TEST_USER_COPY
2355 tristate "Test user/kernel boundary protections"
2358 This builds the "test_user_copy" module that runs sanity checks
2359 on the copy_to/from_user infrastructure, making sure basic
2360 user/kernel boundary testing is working. If it fails to load,
2361 a regression has been detected in the user/kernel memory boundary
2367 tristate "Test BPF filter functionality"
2370 This builds the "test_bpf" module that runs various test vectors
2371 against the BPF interpreter or BPF JIT compiler depending on the
2372 current setting. This is in particular useful for BPF JIT compiler
2373 development, but also to run regression tests against changes in
2374 the interpreter code. It also enables test stubs for eBPF maps and
2375 verifier used by user space verifier testsuite.
2379 config TEST_BLACKHOLE_DEV
2380 tristate "Test blackhole netdev functionality"
2383 This builds the "test_blackhole_dev" module that validates the
2384 data path through this blackhole netdev.
2388 config FIND_BIT_BENCHMARK
2389 tristate "Test find_bit functions"
2391 This builds the "test_find_bit" module that measure find_*_bit()
2392 functions performance.
2396 config TEST_FIRMWARE
2397 tristate "Test firmware loading via userspace interface"
2398 depends on FW_LOADER
2400 This builds the "test_firmware" module that creates a userspace
2401 interface for testing firmware loading. This can be used to
2402 control the triggering of firmware loading without needing an
2403 actual firmware-using device. The contents can be rechecked by
2409 tristate "sysctl test driver"
2410 depends on PROC_SYSCTL
2412 This builds the "test_sysctl" module. This driver enables to test the
2413 proc sysctl interfaces available to drivers safely without affecting
2414 production knobs which might alter system functionality.
2418 config BITFIELD_KUNIT
2419 tristate "KUnit test bitfield functions at runtime"
2422 Enable this option to test the bitfield functions at boot.
2424 KUnit tests run during boot and output the results to the debug log
2425 in TAP format (http://testanything.org/). Only useful for kernel devs
2426 running the KUnit test harness, and not intended for inclusion into a
2429 For more information on KUnit and unit tests in general please refer
2430 to the KUnit documentation in Documentation/dev-tools/kunit/.
2434 config HASH_KUNIT_TEST
2435 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2437 default KUNIT_ALL_TESTS
2439 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2440 integer (<linux/hash.h>) hash functions on boot.
2442 KUnit tests run during boot and output the results to the debug log
2443 in TAP format (https://testanything.org/). Only useful for kernel devs
2444 running the KUnit test harness, and not intended for inclusion into a
2447 For more information on KUnit and unit tests in general please refer
2448 to the KUnit documentation in Documentation/dev-tools/kunit/.
2450 This is intended to help people writing architecture-specific
2451 optimized versions. If unsure, say N.
2453 config RESOURCE_KUNIT_TEST
2454 tristate "KUnit test for resource API"
2457 This builds the resource API unit test.
2458 Tests the logic of API provided by resource.c and ioport.h.
2459 For more information on KUnit and unit tests in general please refer
2460 to the KUnit documentation in Documentation/dev-tools/kunit/.
2464 config SYSCTL_KUNIT_TEST
2465 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2467 default KUNIT_ALL_TESTS
2469 This builds the proc sysctl unit test, which runs on boot.
2470 Tests the API contract and implementation correctness of sysctl.
2471 For more information on KUnit and unit tests in general please refer
2472 to the KUnit documentation in Documentation/dev-tools/kunit/.
2476 config LIST_KUNIT_TEST
2477 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2479 default KUNIT_ALL_TESTS
2481 This builds the linked list KUnit test suite.
2482 It tests that the API and basic functionality of the list_head type
2483 and associated macros.
2485 KUnit tests run during boot and output the results to the debug log
2486 in TAP format (https://testanything.org/). Only useful for kernel devs
2487 running the KUnit test harness, and not intended for inclusion into a
2490 For more information on KUnit and unit tests in general please refer
2491 to the KUnit documentation in Documentation/dev-tools/kunit/.
2495 config LINEAR_RANGES_TEST
2496 tristate "KUnit test for linear_ranges"
2498 select LINEAR_RANGES
2500 This builds the linear_ranges unit test, which runs on boot.
2501 Tests the linear_ranges logic correctness.
2502 For more information on KUnit and unit tests in general please refer
2503 to the KUnit documentation in Documentation/dev-tools/kunit/.
2507 config CMDLINE_KUNIT_TEST
2508 tristate "KUnit test for cmdline API"
2511 This builds the cmdline API unit test.
2512 Tests the logic of API provided by cmdline.c.
2513 For more information on KUnit and unit tests in general please refer
2514 to the KUnit documentation in Documentation/dev-tools/kunit/.
2519 tristate "KUnit test for bits.h"
2522 This builds the bits unit test.
2523 Tests the logic of macros defined in bits.h.
2524 For more information on KUnit and unit tests in general please refer
2525 to the KUnit documentation in Documentation/dev-tools/kunit/.
2529 config SLUB_KUNIT_TEST
2530 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2531 depends on SLUB_DEBUG && KUNIT
2532 default KUNIT_ALL_TESTS
2534 This builds SLUB allocator unit test.
2535 Tests SLUB cache debugging functionality.
2536 For more information on KUnit and unit tests in general please refer
2537 to the KUnit documentation in Documentation/dev-tools/kunit/.
2541 config RATIONAL_KUNIT_TEST
2542 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2543 depends on KUNIT && RATIONAL
2544 default KUNIT_ALL_TESTS
2546 This builds the rational math unit test.
2547 For more information on KUnit and unit tests in general please refer
2548 to the KUnit documentation in Documentation/dev-tools/kunit/.
2552 config MEMCPY_KUNIT_TEST
2553 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2555 default KUNIT_ALL_TESTS
2557 Builds unit tests for memcpy(), memmove(), and memset() functions.
2558 For more information on KUnit and unit tests in general please refer
2559 to the KUnit documentation in Documentation/dev-tools/kunit/.
2563 config OVERFLOW_KUNIT_TEST
2564 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2566 default KUNIT_ALL_TESTS
2568 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2571 For more information on KUnit and unit tests in general please refer
2572 to the KUnit documentation in Documentation/dev-tools/kunit/.
2576 config STACKINIT_KUNIT_TEST
2577 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2579 default KUNIT_ALL_TESTS
2581 Test if the kernel is zero-initializing stack variables and
2582 padding. Coverage is controlled by compiler flags,
2583 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2584 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2585 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2588 tristate "udelay test driver"
2590 This builds the "udelay_test" module that helps to make sure
2591 that udelay() is working properly.
2595 config TEST_STATIC_KEYS
2596 tristate "Test static keys"
2599 Test the static key interfaces.
2604 tristate "kmod stress tester"
2606 depends on NETDEVICES && NET_CORE && INET # for TUN
2608 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2614 Test the kernel's module loading mechanism: kmod. kmod implements
2615 support to load modules using the Linux kernel's usermode helper.
2616 This test provides a series of tests against kmod.
2618 Although technically you can either build test_kmod as a module or
2619 into the kernel we disallow building it into the kernel since
2620 it stress tests request_module() and this will very likely cause
2621 some issues by taking over precious threads available from other
2622 module load requests, ultimately this could be fatal.
2626 tools/testing/selftests/kmod/kmod.sh --help
2630 config TEST_DEBUG_VIRTUAL
2631 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2632 depends on DEBUG_VIRTUAL
2634 Test the kernel's ability to detect incorrect calls to
2635 virt_to_phys() done against the non-linear part of the
2636 kernel's virtual address map.
2640 config TEST_MEMCAT_P
2641 tristate "Test memcat_p() helper function"
2643 Test the memcat_p() helper for correctly merging two
2644 pointer arrays together.
2648 config TEST_LIVEPATCH
2649 tristate "Test livepatching"
2651 depends on DYNAMIC_DEBUG
2652 depends on LIVEPATCH
2655 Test kernel livepatching features for correctness. The tests will
2656 load test modules that will be livepatched in various scenarios.
2658 To run all the livepatching tests:
2660 make -C tools/testing/selftests TARGETS=livepatch run_tests
2662 Alternatively, individual tests may be invoked:
2664 tools/testing/selftests/livepatch/test-callbacks.sh
2665 tools/testing/selftests/livepatch/test-livepatch.sh
2666 tools/testing/selftests/livepatch/test-shadow-vars.sh
2671 tristate "Perform selftest on object aggreration manager"
2675 Enable this option to test object aggregation manager on boot
2679 tristate "Test heap/page initialization"
2681 Test if the kernel is zero-initializing heap and page allocations.
2682 This can be useful to test init_on_alloc and init_on_free features.
2687 tristate "Test HMM (Heterogeneous Memory Management)"
2688 depends on TRANSPARENT_HUGEPAGE
2689 depends on DEVICE_PRIVATE
2693 This is a pseudo device driver solely for testing HMM.
2694 Say M here if you want to build the HMM test module.
2695 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2699 config TEST_FREE_PAGES
2700 tristate "Test freeing pages"
2702 Test that a memory leak does not occur due to a race between
2703 freeing a block of pages and a speculative page reference.
2704 Loading this module is safe if your kernel has the bug fixed.
2705 If the bug is not fixed, it will leak gigabytes of memory and
2706 probably OOM your system.
2709 tristate "Test floating point operations in kernel space"
2710 depends on X86 && !KCOV_INSTRUMENT_ALL
2712 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2713 which will trigger a sequence of floating point operations. This is used
2714 for self-testing floating point control register setting in
2719 config TEST_CLOCKSOURCE_WATCHDOG
2720 tristate "Test clocksource watchdog in kernel space"
2721 depends on CLOCKSOURCE_WATCHDOG
2723 Enable this option to create a kernel module that will trigger
2724 a test of the clocksource watchdog. This module may be loaded
2725 via modprobe or insmod in which case it will run upon being
2726 loaded, or it may be built in, in which case it will run
2731 endif # RUNTIME_TESTING_MENU
2733 config ARCH_USE_MEMTEST
2736 An architecture should select this when it uses early_memtest()
2737 during boot process.
2741 depends on ARCH_USE_MEMTEST
2743 This option adds a kernel parameter 'memtest', which allows memtest
2744 to be set and executed.
2745 memtest=0, mean disabled; -- default
2746 memtest=1, mean do 1 test pattern;
2748 memtest=17, mean do 17 test patterns.
2749 If you are unsure how to answer this question, answer N.
2753 config HYPERV_TESTING
2754 bool "Microsoft Hyper-V driver testing"
2756 depends on HYPERV && DEBUG_FS
2758 Select this option to enable Hyper-V vmbus testing.
2760 endmenu # "Kernel Testing and Coverage"
2762 source "Documentation/Kconfig"
2764 endmenu # Kernel hacking
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