1 # SPDX-License-Identifier: GPL-2.0-only
4 menu "printk and dmesg options"
7 bool "Show timing information on printks"
10 Selecting this option causes time stamps of the printk()
11 messages to be added to the output of the syslog() system
12 call and at the console.
14 The timestamp is always recorded internally, and exported
15 to /dev/kmsg. This flag just specifies if the timestamp should
16 be included, not that the timestamp is recorded.
18 The behavior is also controlled by the kernel command line
19 parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
22 bool "Show caller information on printks"
25 Selecting this option causes printk() to add a caller "thread id" (if
26 in task context) or a caller "processor id" (if not in task context)
29 This option is intended for environments where multiple threads
30 concurrently call printk() for many times, for it is difficult to
31 interpret without knowing where these lines (or sometimes individual
32 line which was divided into multiple lines due to race) came from.
34 Since toggling after boot makes the code racy, currently there is
35 no option to enable/disable at the kernel command line parameter or
38 config STACKTRACE_BUILD_ID
39 bool "Show build ID information in stacktraces"
42 Selecting this option adds build ID information for symbols in
43 stacktraces printed with the printk format '%p[SR]b'.
45 This option is intended for distros where debuginfo is not easily
46 accessible but can be downloaded given the build ID of the vmlinux or
47 kernel module where the function is located.
49 config CONSOLE_LOGLEVEL_DEFAULT
50 int "Default console loglevel (1-15)"
54 Default loglevel to determine what will be printed on the console.
56 Setting a default here is equivalent to passing in loglevel=<x> in
57 the kernel bootargs. loglevel=<x> continues to override whatever
58 value is specified here as well.
60 Note: This does not affect the log level of un-prefixed printk()
61 usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
64 config CONSOLE_LOGLEVEL_QUIET
65 int "quiet console loglevel (1-15)"
69 loglevel to use when "quiet" is passed on the kernel commandline.
71 When "quiet" is passed on the kernel commandline this loglevel
72 will be used as the loglevel. IOW passing "quiet" will be the
73 equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
75 config MESSAGE_LOGLEVEL_DEFAULT
76 int "Default message log level (1-7)"
80 Default log level for printk statements with no specified priority.
82 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
83 that are auditing their logs closely may want to set it to a lower
86 Note: This does not affect what message level gets printed on the console
87 by default. To change that, use loglevel=<x> in the kernel bootargs,
88 or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
90 config BOOT_PRINTK_DELAY
91 bool "Delay each boot printk message by N milliseconds"
92 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
94 This build option allows you to read kernel boot messages
95 by inserting a short delay after each one. The delay is
96 specified in milliseconds on the kernel command line,
99 It is likely that you would also need to use "lpj=M" to preset
100 the "loops per jiffie" value.
101 See a previous boot log for the "lpj" value to use for your
102 system, and then set "lpj=M" before setting "boot_delay=N".
103 NOTE: Using this option may adversely affect SMP systems.
104 I.e., processors other than the first one may not boot up.
105 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
106 what it believes to be lockup conditions.
109 bool "Enable dynamic printk() support"
112 depends on (DEBUG_FS || PROC_FS)
113 select DYNAMIC_DEBUG_CORE
116 Compiles debug level messages into the kernel, which would not
117 otherwise be available at runtime. These messages can then be
118 enabled/disabled based on various levels of scope - per source file,
119 function, module, format string, and line number. This mechanism
120 implicitly compiles in all pr_debug() and dev_dbg() calls, which
121 enlarges the kernel text size by about 2%.
123 If a source file is compiled with DEBUG flag set, any
124 pr_debug() calls in it are enabled by default, but can be
125 disabled at runtime as below. Note that DEBUG flag is
126 turned on by many CONFIG_*DEBUG* options.
130 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
131 which is contained in the 'debugfs' filesystem or procfs.
132 Thus, the debugfs or procfs filesystem must first be mounted before
133 making use of this feature.
134 We refer the control file as: <debugfs>/dynamic_debug/control. This
135 file contains a list of the debug statements that can be enabled. The
136 format for each line of the file is:
138 filename:lineno [module]function flags format
140 filename : source file of the debug statement
141 lineno : line number of the debug statement
142 module : module that contains the debug statement
143 function : function that contains the debug statement
144 flags : '=p' means the line is turned 'on' for printing
145 format : the format used for the debug statement
149 nullarbor:~ # cat <debugfs>/dynamic_debug/control
150 # filename:lineno [module]function flags format
151 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
152 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
153 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
157 // enable the message at line 1603 of file svcsock.c
158 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
159 <debugfs>/dynamic_debug/control
161 // enable all the messages in file svcsock.c
162 nullarbor:~ # echo -n 'file svcsock.c +p' >
163 <debugfs>/dynamic_debug/control
165 // enable all the messages in the NFS server module
166 nullarbor:~ # echo -n 'module nfsd +p' >
167 <debugfs>/dynamic_debug/control
169 // enable all 12 messages in the function svc_process()
170 nullarbor:~ # echo -n 'func svc_process +p' >
171 <debugfs>/dynamic_debug/control
173 // disable all 12 messages in the function svc_process()
174 nullarbor:~ # echo -n 'func svc_process -p' >
175 <debugfs>/dynamic_debug/control
177 See Documentation/admin-guide/dynamic-debug-howto.rst for additional
180 config DYNAMIC_DEBUG_CORE
181 bool "Enable core function of dynamic debug support"
183 depends on (DEBUG_FS || PROC_FS)
185 Enable core functional support of dynamic debug. It is useful
186 when you want to tie dynamic debug to your kernel modules with
187 DYNAMIC_DEBUG_MODULE defined for each of them, especially for
188 the case of embedded system where the kernel image size is
189 sensitive for people.
191 config SYMBOLIC_ERRNAME
192 bool "Support symbolic error names in printf"
195 If you say Y here, the kernel's printf implementation will
196 be able to print symbolic error names such as ENOSPC instead
197 of the number 28. It makes the kernel image slightly larger
198 (about 3KB), but can make the kernel logs easier to read.
200 config DEBUG_BUGVERBOSE
201 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
202 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
205 Say Y here to make BUG() panics output the file name and line number
206 of the BUG call as well as the EIP and oops trace. This aids
207 debugging but costs about 70-100K of memory.
209 endmenu # "printk and dmesg options"
212 bool "Kernel debugging"
214 Say Y here if you are developing drivers or trying to debug and
215 identify kernel problems.
218 bool "Miscellaneous debug code"
220 depends on DEBUG_KERNEL
222 Say Y here if you need to enable miscellaneous debug code that should
223 be under a more specific debug option but isn't.
225 menu "Compile-time checks and compiler options"
230 A kernel debug info option other than "None" has been selected
231 in the "Debug information" choice below, indicating that debug
232 information will be generated for build targets.
235 prompt "Debug information"
236 depends on DEBUG_KERNEL
238 Selecting something other than "None" results in a kernel image
239 that will include debugging info resulting in a larger kernel image.
240 This adds debug symbols to the kernel and modules (gcc -g), and
241 is needed if you intend to use kernel crashdump or binary object
242 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
244 Choose which version of DWARF debug info to emit. If unsure,
245 select "Toolchain default".
247 config DEBUG_INFO_NONE
248 bool "Disable debug information"
250 Do not build the kernel with debugging information, which will
251 result in a faster and smaller build.
253 config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
254 bool "Rely on the toolchain's implicit default DWARF version"
257 The implicit default version of DWARF debug info produced by a
258 toolchain changes over time.
260 This can break consumers of the debug info that haven't upgraded to
261 support newer revisions, and prevent testing newer versions, but
262 those should be less common scenarios.
264 config DEBUG_INFO_DWARF4
265 bool "Generate DWARF Version 4 debuginfo"
268 Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+.
270 If you have consumers of DWARF debug info that are not ready for
271 newer revisions of DWARF, you may wish to choose this or have your
274 config DEBUG_INFO_DWARF5
275 bool "Generate DWARF Version 5 debuginfo"
277 depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)))
279 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
280 5.0+ accepts the -gdwarf-5 flag but only had partial support for some
281 draft features until 7.0), and gdb 8.0+.
283 Changes to the structure of debug info in Version 5 allow for around
284 15-18% savings in resulting image and debug info section sizes as
285 compared to DWARF Version 4. DWARF Version 5 standardizes previous
286 extensions such as accelerators for symbol indexing and the format
287 for fission (.dwo/.dwp) files. Users may not want to select this
288 config if they rely on tooling that has not yet been updated to
289 support DWARF Version 5.
291 endchoice # "Debug information"
295 config DEBUG_INFO_REDUCED
296 bool "Reduce debugging information"
298 If you say Y here gcc is instructed to generate less debugging
299 information for structure types. This means that tools that
300 need full debugging information (like kgdb or systemtap) won't
301 be happy. But if you merely need debugging information to
302 resolve line numbers there is no loss. Advantage is that
303 build directory object sizes shrink dramatically over a full
304 DEBUG_INFO build and compile times are reduced too.
305 Only works with newer gcc versions.
307 config DEBUG_INFO_COMPRESSED
308 bool "Compressed debugging information"
309 depends on $(cc-option,-gz=zlib)
310 depends on $(ld-option,--compress-debug-sections=zlib)
312 Compress the debug information using zlib. Requires GCC 5.0+ or Clang
313 5.0+, binutils 2.26+, and zlib.
315 Users of dpkg-deb via scripts/package/builddeb may find an increase in
316 size of their debug .deb packages with this config set, due to the
317 debug info being compressed with zlib, then the object files being
318 recompressed with a different compression scheme. But this is still
319 preferable to setting $KDEB_COMPRESS to "none" which would be even
322 config DEBUG_INFO_SPLIT
323 bool "Produce split debuginfo in .dwo files"
324 depends on $(cc-option,-gsplit-dwarf)
326 Generate debug info into separate .dwo files. This significantly
327 reduces the build directory size for builds with DEBUG_INFO,
328 because it stores the information only once on disk in .dwo
329 files instead of multiple times in object files and executables.
330 In addition the debug information is also compressed.
332 Requires recent gcc (4.7+) and recent gdb/binutils.
333 Any tool that packages or reads debug information would need
334 to know about the .dwo files and include them.
335 Incompatible with older versions of ccache.
337 config DEBUG_INFO_BTF
338 bool "Generate BTF typeinfo"
339 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
340 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
341 depends on BPF_SYSCALL
342 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121
344 Generate deduplicated BTF type information from DWARF debug info.
345 Turning this on expects presence of pahole tool, which will convert
346 DWARF type info into equivalent deduplicated BTF type info.
348 config PAHOLE_HAS_SPLIT_BTF
349 def_bool PAHOLE_VERSION >= 119
351 config PAHOLE_HAS_BTF_TAG
352 def_bool PAHOLE_VERSION >= 123
353 depends on CC_IS_CLANG
355 Decide whether pahole emits btf_tag attributes (btf_type_tag and
356 btf_decl_tag) or not. Currently only clang compiler implements
357 these attributes, so make the config depend on CC_IS_CLANG.
359 config DEBUG_INFO_BTF_MODULES
361 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
363 Generate compact split BTF type information for kernel modules.
365 config MODULE_ALLOW_BTF_MISMATCH
366 bool "Allow loading modules with non-matching BTF type info"
367 depends on DEBUG_INFO_BTF_MODULES
369 For modules whose split BTF does not match vmlinux, load without
370 BTF rather than refusing to load. The default behavior with
371 module BTF enabled is to reject modules with such mismatches;
372 this option will still load module BTF where possible but ignore
373 it when a mismatch is found.
376 bool "Provide GDB scripts for kernel debugging"
378 This creates the required links to GDB helper scripts in the
379 build directory. If you load vmlinux into gdb, the helper
380 scripts will be automatically imported by gdb as well, and
381 additional functions are available to analyze a Linux kernel
382 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
388 int "Warn for stack frames larger than"
390 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
391 default 2048 if PARISC
392 default 1536 if (!64BIT && XTENSA)
393 default 1024 if !64BIT
394 default 2048 if 64BIT
396 Tell gcc to warn at build time for stack frames larger than this.
397 Setting this too low will cause a lot of warnings.
398 Setting it to 0 disables the warning.
400 config STRIP_ASM_SYMS
401 bool "Strip assembler-generated symbols during link"
404 Strip internal assembler-generated symbols during a link (symbols
405 that look like '.Lxxx') so they don't pollute the output of
406 get_wchan() and suchlike.
409 bool "Generate readable assembler code"
410 depends on DEBUG_KERNEL
413 Disable some compiler optimizations that tend to generate human unreadable
414 assembler output. This may make the kernel slightly slower, but it helps
415 to keep kernel developers who have to stare a lot at assembler listings
418 config HEADERS_INSTALL
419 bool "Install uapi headers to usr/include"
422 This option will install uapi headers (headers exported to user-space)
423 into the usr/include directory for use during the kernel build.
424 This is unneeded for building the kernel itself, but needed for some
425 user-space program samples. It is also needed by some features such
426 as uapi header sanity checks.
428 config DEBUG_SECTION_MISMATCH
429 bool "Enable full Section mismatch analysis"
432 The section mismatch analysis checks if there are illegal
433 references from one section to another section.
434 During linktime or runtime, some sections are dropped;
435 any use of code/data previously in these sections would
436 most likely result in an oops.
437 In the code, functions and variables are annotated with
438 __init,, etc. (see the full list in include/linux/init.h),
439 which results in the code/data being placed in specific sections.
440 The section mismatch analysis is always performed after a full
441 kernel build, and enabling this option causes the following
442 additional step to occur:
443 - Add the option -fno-inline-functions-called-once to gcc commands.
444 When inlining a function annotated with __init in a non-init
445 function, we would lose the section information and thus
446 the analysis would not catch the illegal reference.
447 This option tells gcc to inline less (but it does result in
450 config SECTION_MISMATCH_WARN_ONLY
451 bool "Make section mismatch errors non-fatal"
454 If you say N here, the build process will fail if there are any
455 section mismatch, instead of just throwing warnings.
459 config DEBUG_FORCE_FUNCTION_ALIGN_64B
460 bool "Force all function address 64B aligned"
461 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC)
463 There are cases that a commit from one domain changes the function
464 address alignment of other domains, and cause magic performance
465 bump (regression or improvement). Enable this option will help to
466 verify if the bump is caused by function alignment changes, while
467 it will slightly increase the kernel size and affect icache usage.
469 It is mainly for debug and performance tuning use.
472 # Select this config option from the architecture Kconfig, if it
473 # is preferred to always offer frame pointers as a config
474 # option on the architecture (regardless of KERNEL_DEBUG):
476 config ARCH_WANT_FRAME_POINTERS
480 bool "Compile the kernel with frame pointers"
481 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
482 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
484 If you say Y here the resulting kernel image will be slightly
485 larger and slower, but it gives very useful debugging information
486 in case of kernel bugs. (precise oopses/stacktraces/warnings)
491 config STACK_VALIDATION
492 bool "Compile-time stack metadata validation"
493 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
497 Validate frame pointer rules at compile-time. This helps ensure that
498 runtime stack traces are more reliable.
500 For more information, see
501 tools/objtool/Documentation/stack-validation.txt.
503 config NOINSTR_VALIDATION
505 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
510 bool "Generate vmlinux.map file when linking"
513 Selecting this option will pass "-Map=vmlinux.map" to ld
514 when linking vmlinux. That file can be useful for verifying
515 and debugging magic section games, and for seeing which
516 pieces of code get eliminated with
517 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
519 config DEBUG_FORCE_WEAK_PER_CPU
520 bool "Force weak per-cpu definitions"
521 depends on DEBUG_KERNEL
523 s390 and alpha require percpu variables in modules to be
524 defined weak to work around addressing range issue which
525 puts the following two restrictions on percpu variable
528 1. percpu symbols must be unique whether static or not
529 2. percpu variables can't be defined inside a function
531 To ensure that generic code follows the above rules, this
532 option forces all percpu variables to be defined as weak.
534 endmenu # "Compiler options"
536 menu "Generic Kernel Debugging Instruments"
539 bool "Magic SysRq key"
542 If you say Y here, you will have some control over the system even
543 if the system crashes for example during kernel debugging (e.g., you
544 will be able to flush the buffer cache to disk, reboot the system
545 immediately or dump some status information). This is accomplished
546 by pressing various keys while holding SysRq (Alt+PrintScreen). It
547 also works on a serial console (on PC hardware at least), if you
548 send a BREAK and then within 5 seconds a command keypress. The
549 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
550 Don't say Y unless you really know what this hack does.
552 config MAGIC_SYSRQ_DEFAULT_ENABLE
553 hex "Enable magic SysRq key functions by default"
554 depends on MAGIC_SYSRQ
557 Specifies which SysRq key functions are enabled by default.
558 This may be set to 1 or 0 to enable or disable them all, or
559 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
561 config MAGIC_SYSRQ_SERIAL
562 bool "Enable magic SysRq key over serial"
563 depends on MAGIC_SYSRQ
566 Many embedded boards have a disconnected TTL level serial which can
567 generate some garbage that can lead to spurious false sysrq detects.
568 This option allows you to decide whether you want to enable the
571 config MAGIC_SYSRQ_SERIAL_SEQUENCE
572 string "Char sequence that enables magic SysRq over serial"
573 depends on MAGIC_SYSRQ_SERIAL
576 Specifies a sequence of characters that can follow BREAK to enable
577 SysRq on a serial console.
579 If unsure, leave an empty string and the option will not be enabled.
582 bool "Debug Filesystem"
584 debugfs is a virtual file system that kernel developers use to put
585 debugging files into. Enable this option to be able to read and
586 write to these files.
588 For detailed documentation on the debugfs API, see
589 Documentation/filesystems/.
594 prompt "Debugfs default access"
596 default DEBUG_FS_ALLOW_ALL
598 This selects the default access restrictions for debugfs.
599 It can be overridden with kernel command line option
600 debugfs=[on,no-mount,off]. The restrictions apply for API access
601 and filesystem registration.
603 config DEBUG_FS_ALLOW_ALL
606 No restrictions apply. Both API and filesystem registration
607 is on. This is the normal default operation.
609 config DEBUG_FS_DISALLOW_MOUNT
610 bool "Do not register debugfs as filesystem"
612 The API is open but filesystem is not loaded. Clients can still do
613 their work and read with debug tools that do not need
616 config DEBUG_FS_ALLOW_NONE
619 Access is off. Clients get -PERM when trying to create nodes in
620 debugfs tree and debugfs is not registered as a filesystem.
621 Client can then back-off or continue without debugfs access.
625 source "lib/Kconfig.kgdb"
626 source "lib/Kconfig.ubsan"
627 source "lib/Kconfig.kcsan"
631 menu "Networking Debugging"
633 source "net/Kconfig.debug"
635 endmenu # "Networking Debugging"
637 menu "Memory Debugging"
639 source "mm/Kconfig.debug"
642 bool "Debug object operations"
643 depends on DEBUG_KERNEL
645 If you say Y here, additional code will be inserted into the
646 kernel to track the life time of various objects and validate
647 the operations on those objects.
649 config DEBUG_OBJECTS_SELFTEST
650 bool "Debug objects selftest"
651 depends on DEBUG_OBJECTS
653 This enables the selftest of the object debug code.
655 config DEBUG_OBJECTS_FREE
656 bool "Debug objects in freed memory"
657 depends on DEBUG_OBJECTS
659 This enables checks whether a k/v free operation frees an area
660 which contains an object which has not been deactivated
661 properly. This can make kmalloc/kfree-intensive workloads
664 config DEBUG_OBJECTS_TIMERS
665 bool "Debug timer objects"
666 depends on DEBUG_OBJECTS
668 If you say Y here, additional code will be inserted into the
669 timer routines to track the life time of timer objects and
670 validate the timer operations.
672 config DEBUG_OBJECTS_WORK
673 bool "Debug work objects"
674 depends on DEBUG_OBJECTS
676 If you say Y here, additional code will be inserted into the
677 work queue routines to track the life time of work objects and
678 validate the work operations.
680 config DEBUG_OBJECTS_RCU_HEAD
681 bool "Debug RCU callbacks objects"
682 depends on DEBUG_OBJECTS
684 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
686 config DEBUG_OBJECTS_PERCPU_COUNTER
687 bool "Debug percpu counter objects"
688 depends on DEBUG_OBJECTS
690 If you say Y here, additional code will be inserted into the
691 percpu counter routines to track the life time of percpu counter
692 objects and validate the percpu counter operations.
694 config DEBUG_OBJECTS_ENABLE_DEFAULT
695 int "debug_objects bootup default value (0-1)"
698 depends on DEBUG_OBJECTS
700 Debug objects boot parameter default value
703 bool "Debug slab memory allocations"
704 depends on DEBUG_KERNEL && SLAB
706 Say Y here to have the kernel do limited verification on memory
707 allocation as well as poisoning memory on free to catch use of freed
708 memory. This can make kmalloc/kfree-intensive workloads much slower.
711 bool "SLUB debugging on by default"
712 depends on SLUB && SLUB_DEBUG
715 Boot with debugging on by default. SLUB boots by default with
716 the runtime debug capabilities switched off. Enabling this is
717 equivalent to specifying the "slub_debug" parameter on boot.
718 There is no support for more fine grained debug control like
719 possible with slub_debug=xxx. SLUB debugging may be switched
720 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
725 bool "Enable SLUB performance statistics"
726 depends on SLUB && SYSFS
728 SLUB statistics are useful to debug SLUBs allocation behavior in
729 order find ways to optimize the allocator. This should never be
730 enabled for production use since keeping statistics slows down
731 the allocator by a few percentage points. The slabinfo command
732 supports the determination of the most active slabs to figure
733 out which slabs are relevant to a particular load.
734 Try running: slabinfo -DA
736 config HAVE_DEBUG_KMEMLEAK
739 config DEBUG_KMEMLEAK
740 bool "Kernel memory leak detector"
741 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
743 select STACKTRACE if STACKTRACE_SUPPORT
747 Say Y here if you want to enable the memory leak
748 detector. The memory allocation/freeing is traced in a way
749 similar to the Boehm's conservative garbage collector, the
750 difference being that the orphan objects are not freed but
751 only shown in /sys/kernel/debug/kmemleak. Enabling this
752 feature will introduce an overhead to memory
753 allocations. See Documentation/dev-tools/kmemleak.rst for more
756 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
757 of finding leaks due to the slab objects poisoning.
759 In order to access the kmemleak file, debugfs needs to be
760 mounted (usually at /sys/kernel/debug).
762 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
763 int "Kmemleak memory pool size"
764 depends on DEBUG_KMEMLEAK
768 Kmemleak must track all the memory allocations to avoid
769 reporting false positives. Since memory may be allocated or
770 freed before kmemleak is fully initialised, use a static pool
771 of metadata objects to track such callbacks. After kmemleak is
772 fully initialised, this memory pool acts as an emergency one
773 if slab allocations fail.
775 config DEBUG_KMEMLEAK_TEST
776 tristate "Simple test for the kernel memory leak detector"
777 depends on DEBUG_KMEMLEAK && m
779 This option enables a module that explicitly leaks memory.
783 config DEBUG_KMEMLEAK_DEFAULT_OFF
784 bool "Default kmemleak to off"
785 depends on DEBUG_KMEMLEAK
787 Say Y here to disable kmemleak by default. It can then be enabled
788 on the command line via kmemleak=on.
790 config DEBUG_KMEMLEAK_AUTO_SCAN
791 bool "Enable kmemleak auto scan thread on boot up"
793 depends on DEBUG_KMEMLEAK
795 Depending on the cpu, kmemleak scan may be cpu intensive and can
796 stall user tasks at times. This option enables/disables automatic
797 kmemleak scan at boot up.
799 Say N here to disable kmemleak auto scan thread to stop automatic
800 scanning. Disabling this option disables automatic reporting of
805 config DEBUG_STACK_USAGE
806 bool "Stack utilization instrumentation"
807 depends on DEBUG_KERNEL && !IA64
809 Enables the display of the minimum amount of free stack which each
810 task has ever had available in the sysrq-T and sysrq-P debug output.
812 This option will slow down process creation somewhat.
814 config SCHED_STACK_END_CHECK
815 bool "Detect stack corruption on calls to schedule()"
816 depends on DEBUG_KERNEL
819 This option checks for a stack overrun on calls to schedule().
820 If the stack end location is found to be over written always panic as
821 the content of the corrupted region can no longer be trusted.
822 This is to ensure no erroneous behaviour occurs which could result in
823 data corruption or a sporadic crash at a later stage once the region
824 is examined. The runtime overhead introduced is minimal.
826 config ARCH_HAS_DEBUG_VM_PGTABLE
829 An architecture should select this when it can successfully
830 build and run DEBUG_VM_PGTABLE.
834 depends on DEBUG_KERNEL
836 Enable this to turn on extended checks in the virtual-memory system
837 that may impact performance.
841 config DEBUG_VM_VMACACHE
842 bool "Debug VMA caching"
845 Enable this to turn on VMA caching debug information. Doing so
846 can cause significant overhead, so only enable it in non-production
852 bool "Debug VM red-black trees"
855 Enable VM red-black tree debugging information and extra validations.
859 config DEBUG_VM_PGFLAGS
860 bool "Debug page-flags operations"
863 Enables extra validation on page flags operations.
867 config DEBUG_VM_PGTABLE
868 bool "Debug arch page table for semantics compliance"
870 depends on ARCH_HAS_DEBUG_VM_PGTABLE
871 default y if DEBUG_VM
873 This option provides a debug method which can be used to test
874 architecture page table helper functions on various platforms in
875 verifying if they comply with expected generic MM semantics. This
876 will help architecture code in making sure that any changes or
877 new additions of these helpers still conform to expected
878 semantics of the generic MM. Platforms will have to opt in for
879 this through ARCH_HAS_DEBUG_VM_PGTABLE.
883 config ARCH_HAS_DEBUG_VIRTUAL
887 bool "Debug VM translations"
888 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
890 Enable some costly sanity checks in virtual to page code. This can
891 catch mistakes with virt_to_page() and friends.
895 config DEBUG_NOMMU_REGIONS
896 bool "Debug the global anon/private NOMMU mapping region tree"
897 depends on DEBUG_KERNEL && !MMU
899 This option causes the global tree of anonymous and private mapping
900 regions to be regularly checked for invalid topology.
902 config DEBUG_MEMORY_INIT
903 bool "Debug memory initialisation" if EXPERT
906 Enable this for additional checks during memory initialisation.
907 The sanity checks verify aspects of the VM such as the memory model
908 and other information provided by the architecture. Verbose
909 information will be printed at KERN_DEBUG loglevel depending
910 on the mminit_loglevel= command-line option.
914 config MEMORY_NOTIFIER_ERROR_INJECT
915 tristate "Memory hotplug notifier error injection module"
916 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
918 This option provides the ability to inject artificial errors to
919 memory hotplug notifier chain callbacks. It is controlled through
920 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
922 If the notifier call chain should be failed with some events
923 notified, write the error code to "actions/<notifier event>/error".
925 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
927 # cd /sys/kernel/debug/notifier-error-inject/memory
928 # echo -12 > actions/MEM_GOING_OFFLINE/error
929 # echo offline > /sys/devices/system/memory/memoryXXX/state
930 bash: echo: write error: Cannot allocate memory
932 To compile this code as a module, choose M here: the module will
933 be called memory-notifier-error-inject.
937 config DEBUG_PER_CPU_MAPS
938 bool "Debug access to per_cpu maps"
939 depends on DEBUG_KERNEL
942 Say Y to verify that the per_cpu map being accessed has
943 been set up. This adds a fair amount of code to kernel memory
944 and decreases performance.
948 config DEBUG_KMAP_LOCAL
949 bool "Debug kmap_local temporary mappings"
950 depends on DEBUG_KERNEL && KMAP_LOCAL
952 This option enables additional error checking for the kmap_local
953 infrastructure. Disable for production use.
955 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
958 config DEBUG_KMAP_LOCAL_FORCE_MAP
959 bool "Enforce kmap_local temporary mappings"
960 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
962 select DEBUG_KMAP_LOCAL
964 This option enforces temporary mappings through the kmap_local
965 mechanism for non-highmem pages and on non-highmem systems.
966 Disable this for production systems!
969 bool "Highmem debugging"
970 depends on DEBUG_KERNEL && HIGHMEM
971 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
972 select DEBUG_KMAP_LOCAL
974 This option enables additional error checking for high memory
975 systems. Disable for production systems.
977 config HAVE_DEBUG_STACKOVERFLOW
980 config DEBUG_STACKOVERFLOW
981 bool "Check for stack overflows"
982 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
984 Say Y here if you want to check for overflows of kernel, IRQ
985 and exception stacks (if your architecture uses them). This
986 option will show detailed messages if free stack space drops
987 below a certain limit.
989 These kinds of bugs usually occur when call-chains in the
990 kernel get too deep, especially when interrupts are
993 Use this in cases where you see apparently random memory
994 corruption, especially if it appears in 'struct thread_info'
996 If in doubt, say "N".
998 source "lib/Kconfig.kasan"
999 source "lib/Kconfig.kfence"
1001 endmenu # "Memory Debugging"
1004 bool "Debug shared IRQ handlers"
1005 depends on DEBUG_KERNEL
1007 Enable this to generate a spurious interrupt just before a shared
1008 interrupt handler is deregistered (generating one when registering
1009 is currently disabled). Drivers need to handle this correctly. Some
1010 don't and need to be caught.
1012 menu "Debug Oops, Lockups and Hangs"
1014 config PANIC_ON_OOPS
1015 bool "Panic on Oops"
1017 Say Y here to enable the kernel to panic when it oopses. This
1018 has the same effect as setting oops=panic on the kernel command
1021 This feature is useful to ensure that the kernel does not do
1022 anything erroneous after an oops which could result in data
1023 corruption or other issues.
1027 config PANIC_ON_OOPS_VALUE
1030 default 0 if !PANIC_ON_OOPS
1031 default 1 if PANIC_ON_OOPS
1033 config PANIC_TIMEOUT
1037 Set the timeout value (in seconds) until a reboot occurs when
1038 the kernel panics. If n = 0, then we wait forever. A timeout
1039 value n > 0 will wait n seconds before rebooting, while a timeout
1040 value n < 0 will reboot immediately.
1042 config LOCKUP_DETECTOR
1045 config SOFTLOCKUP_DETECTOR
1046 bool "Detect Soft Lockups"
1047 depends on DEBUG_KERNEL && !S390
1048 select LOCKUP_DETECTOR
1050 Say Y here to enable the kernel to act as a watchdog to detect
1053 Softlockups are bugs that cause the kernel to loop in kernel
1054 mode for more than 20 seconds, without giving other tasks a
1055 chance to run. The current stack trace is displayed upon
1056 detection and the system will stay locked up.
1058 config BOOTPARAM_SOFTLOCKUP_PANIC
1059 bool "Panic (Reboot) On Soft Lockups"
1060 depends on SOFTLOCKUP_DETECTOR
1062 Say Y here to enable the kernel to panic on "soft lockups",
1063 which are bugs that cause the kernel to loop in kernel
1064 mode for more than 20 seconds (configurable using the watchdog_thresh
1065 sysctl), without giving other tasks a chance to run.
1067 The panic can be used in combination with panic_timeout,
1068 to cause the system to reboot automatically after a
1069 lockup has been detected. This feature is useful for
1070 high-availability systems that have uptime guarantees and
1071 where a lockup must be resolved ASAP.
1075 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
1077 depends on SOFTLOCKUP_DETECTOR
1079 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
1080 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
1082 config HARDLOCKUP_DETECTOR_PERF
1084 select SOFTLOCKUP_DETECTOR
1087 # Enables a timestamp based low pass filter to compensate for perf based
1088 # hard lockup detection which runs too fast due to turbo modes.
1090 config HARDLOCKUP_CHECK_TIMESTAMP
1094 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1095 # lockup detector rather than the perf based detector.
1097 config HARDLOCKUP_DETECTOR
1098 bool "Detect Hard Lockups"
1099 depends on DEBUG_KERNEL && !S390
1100 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1101 select LOCKUP_DETECTOR
1102 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1104 Say Y here to enable the kernel to act as a watchdog to detect
1107 Hardlockups are bugs that cause the CPU to loop in kernel mode
1108 for more than 10 seconds, without letting other interrupts have a
1109 chance to run. The current stack trace is displayed upon detection
1110 and the system will stay locked up.
1112 config BOOTPARAM_HARDLOCKUP_PANIC
1113 bool "Panic (Reboot) On Hard Lockups"
1114 depends on HARDLOCKUP_DETECTOR
1116 Say Y here to enable the kernel to panic on "hard lockups",
1117 which are bugs that cause the kernel to loop in kernel
1118 mode with interrupts disabled for more than 10 seconds (configurable
1119 using the watchdog_thresh sysctl).
1123 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
1125 depends on HARDLOCKUP_DETECTOR
1127 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
1128 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
1130 config DETECT_HUNG_TASK
1131 bool "Detect Hung Tasks"
1132 depends on DEBUG_KERNEL
1133 default SOFTLOCKUP_DETECTOR
1135 Say Y here to enable the kernel to detect "hung tasks",
1136 which are bugs that cause the task to be stuck in
1137 uninterruptible "D" state indefinitely.
1139 When a hung task is detected, the kernel will print the
1140 current stack trace (which you should report), but the
1141 task will stay in uninterruptible state. If lockdep is
1142 enabled then all held locks will also be reported. This
1143 feature has negligible overhead.
1145 config DEFAULT_HUNG_TASK_TIMEOUT
1146 int "Default timeout for hung task detection (in seconds)"
1147 depends on DETECT_HUNG_TASK
1150 This option controls the default timeout (in seconds) used
1151 to determine when a task has become non-responsive and should
1154 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1155 sysctl or by writing a value to
1156 /proc/sys/kernel/hung_task_timeout_secs.
1158 A timeout of 0 disables the check. The default is two minutes.
1159 Keeping the default should be fine in most cases.
1161 config BOOTPARAM_HUNG_TASK_PANIC
1162 bool "Panic (Reboot) On Hung Tasks"
1163 depends on DETECT_HUNG_TASK
1165 Say Y here to enable the kernel to panic on "hung tasks",
1166 which are bugs that cause the kernel to leave a task stuck
1167 in uninterruptible "D" state.
1169 The panic can be used in combination with panic_timeout,
1170 to cause the system to reboot automatically after a
1171 hung task has been detected. This feature is useful for
1172 high-availability systems that have uptime guarantees and
1173 where a hung tasks must be resolved ASAP.
1177 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
1179 depends on DETECT_HUNG_TASK
1181 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
1182 default 1 if BOOTPARAM_HUNG_TASK_PANIC
1185 bool "Detect Workqueue Stalls"
1186 depends on DEBUG_KERNEL
1188 Say Y here to enable stall detection on workqueues. If a
1189 worker pool doesn't make forward progress on a pending work
1190 item for over a given amount of time, 30s by default, a
1191 warning message is printed along with dump of workqueue
1192 state. This can be configured through kernel parameter
1193 "workqueue.watchdog_thresh" and its sysfs counterpart.
1196 tristate "Test module to generate lockups"
1199 This builds the "test_lockup" module that helps to make sure
1200 that watchdogs and lockup detectors are working properly.
1202 Depending on module parameters it could emulate soft or hard
1203 lockup, "hung task", or locking arbitrary lock for a long time.
1204 Also it could generate series of lockups with cooling-down periods.
1208 endmenu # "Debug lockups and hangs"
1210 menu "Scheduler Debugging"
1213 bool "Collect scheduler debugging info"
1214 depends on DEBUG_KERNEL && PROC_FS
1217 If you say Y here, the /proc/sched_debug file will be provided
1218 that can help debug the scheduler. The runtime overhead of this
1226 bool "Collect scheduler statistics"
1227 depends on DEBUG_KERNEL && PROC_FS
1230 If you say Y here, additional code will be inserted into the
1231 scheduler and related routines to collect statistics about
1232 scheduler behavior and provide them in /proc/schedstat. These
1233 stats may be useful for both tuning and debugging the scheduler
1234 If you aren't debugging the scheduler or trying to tune a specific
1235 application, you can say N to avoid the very slight overhead
1240 config DEBUG_TIMEKEEPING
1241 bool "Enable extra timekeeping sanity checking"
1243 This option will enable additional timekeeping sanity checks
1244 which may be helpful when diagnosing issues where timekeeping
1245 problems are suspected.
1247 This may include checks in the timekeeping hotpaths, so this
1248 option may have a (very small) performance impact to some
1253 config DEBUG_PREEMPT
1254 bool "Debug preemptible kernel"
1255 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1258 If you say Y here then the kernel will use a debug variant of the
1259 commonly used smp_processor_id() function and will print warnings
1260 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1261 will detect preemption count underflows.
1263 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1265 config LOCK_DEBUGGING_SUPPORT
1267 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1270 config PROVE_LOCKING
1271 bool "Lock debugging: prove locking correctness"
1272 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1274 select DEBUG_SPINLOCK
1275 select DEBUG_MUTEXES if !PREEMPT_RT
1276 select DEBUG_RT_MUTEXES if RT_MUTEXES
1278 select DEBUG_WW_MUTEX_SLOWPATH
1279 select DEBUG_LOCK_ALLOC
1280 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1281 select TRACE_IRQFLAGS
1284 This feature enables the kernel to prove that all locking
1285 that occurs in the kernel runtime is mathematically
1286 correct: that under no circumstance could an arbitrary (and
1287 not yet triggered) combination of observed locking
1288 sequences (on an arbitrary number of CPUs, running an
1289 arbitrary number of tasks and interrupt contexts) cause a
1292 In short, this feature enables the kernel to report locking
1293 related deadlocks before they actually occur.
1295 The proof does not depend on how hard and complex a
1296 deadlock scenario would be to trigger: how many
1297 participant CPUs, tasks and irq-contexts would be needed
1298 for it to trigger. The proof also does not depend on
1299 timing: if a race and a resulting deadlock is possible
1300 theoretically (no matter how unlikely the race scenario
1301 is), it will be proven so and will immediately be
1302 reported by the kernel (once the event is observed that
1303 makes the deadlock theoretically possible).
1305 If a deadlock is impossible (i.e. the locking rules, as
1306 observed by the kernel, are mathematically correct), the
1307 kernel reports nothing.
1309 NOTE: this feature can also be enabled for rwlocks, mutexes
1310 and rwsems - in which case all dependencies between these
1311 different locking variants are observed and mapped too, and
1312 the proof of observed correctness is also maintained for an
1313 arbitrary combination of these separate locking variants.
1315 For more details, see Documentation/locking/lockdep-design.rst.
1317 config PROVE_RAW_LOCK_NESTING
1318 bool "Enable raw_spinlock - spinlock nesting checks"
1319 depends on PROVE_LOCKING
1322 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1323 that the lock nesting rules for PREEMPT_RT enabled kernels are
1326 NOTE: There are known nesting problems. So if you enable this
1327 option expect lockdep splats until these problems have been fully
1328 addressed which is work in progress. This config switch allows to
1329 identify and analyze these problems. It will be removed and the
1330 check permanently enabled once the main issues have been fixed.
1332 If unsure, select N.
1335 bool "Lock usage statistics"
1336 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1338 select DEBUG_SPINLOCK
1339 select DEBUG_MUTEXES if !PREEMPT_RT
1340 select DEBUG_RT_MUTEXES if RT_MUTEXES
1341 select DEBUG_LOCK_ALLOC
1344 This feature enables tracking lock contention points
1346 For more details, see Documentation/locking/lockstat.rst
1348 This also enables lock events required by "perf lock",
1350 If you want to use "perf lock", you also need to turn on
1351 CONFIG_EVENT_TRACING.
1353 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1354 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1356 config DEBUG_RT_MUTEXES
1357 bool "RT Mutex debugging, deadlock detection"
1358 depends on DEBUG_KERNEL && RT_MUTEXES
1360 This allows rt mutex semantics violations and rt mutex related
1361 deadlocks (lockups) to be detected and reported automatically.
1363 config DEBUG_SPINLOCK
1364 bool "Spinlock and rw-lock debugging: basic checks"
1365 depends on DEBUG_KERNEL
1366 select UNINLINE_SPIN_UNLOCK
1368 Say Y here and build SMP to catch missing spinlock initialization
1369 and certain other kinds of spinlock errors commonly made. This is
1370 best used in conjunction with the NMI watchdog so that spinlock
1371 deadlocks are also debuggable.
1373 config DEBUG_MUTEXES
1374 bool "Mutex debugging: basic checks"
1375 depends on DEBUG_KERNEL && !PREEMPT_RT
1377 This feature allows mutex semantics violations to be detected and
1380 config DEBUG_WW_MUTEX_SLOWPATH
1381 bool "Wait/wound mutex debugging: Slowpath testing"
1382 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1383 select DEBUG_LOCK_ALLOC
1384 select DEBUG_SPINLOCK
1385 select DEBUG_MUTEXES if !PREEMPT_RT
1386 select DEBUG_RT_MUTEXES if PREEMPT_RT
1388 This feature enables slowpath testing for w/w mutex users by
1389 injecting additional -EDEADLK wound/backoff cases. Together with
1390 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1391 will test all possible w/w mutex interface abuse with the
1392 exception of simply not acquiring all the required locks.
1393 Note that this feature can introduce significant overhead, so
1394 it really should not be enabled in a production or distro kernel,
1395 even a debug kernel. If you are a driver writer, enable it. If
1396 you are a distro, do not.
1399 bool "RW Semaphore debugging: basic checks"
1400 depends on DEBUG_KERNEL
1402 This debugging feature allows mismatched rw semaphore locks
1403 and unlocks to be detected and reported.
1405 config DEBUG_LOCK_ALLOC
1406 bool "Lock debugging: detect incorrect freeing of live locks"
1407 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1408 select DEBUG_SPINLOCK
1409 select DEBUG_MUTEXES if !PREEMPT_RT
1410 select DEBUG_RT_MUTEXES if RT_MUTEXES
1413 This feature will check whether any held lock (spinlock, rwlock,
1414 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1415 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1416 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1417 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1418 held during task exit.
1422 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1427 config LOCKDEP_SMALL
1431 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1432 depends on LOCKDEP && !LOCKDEP_SMALL
1436 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1438 config LOCKDEP_CHAINS_BITS
1439 int "Bitsize for MAX_LOCKDEP_CHAINS"
1440 depends on LOCKDEP && !LOCKDEP_SMALL
1444 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1446 config LOCKDEP_STACK_TRACE_BITS
1447 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1448 depends on LOCKDEP && !LOCKDEP_SMALL
1452 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1454 config LOCKDEP_STACK_TRACE_HASH_BITS
1455 int "Bitsize for STACK_TRACE_HASH_SIZE"
1456 depends on LOCKDEP && !LOCKDEP_SMALL
1460 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1462 config LOCKDEP_CIRCULAR_QUEUE_BITS
1463 int "Bitsize for elements in circular_queue struct"
1468 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1470 config DEBUG_LOCKDEP
1471 bool "Lock dependency engine debugging"
1472 depends on DEBUG_KERNEL && LOCKDEP
1473 select DEBUG_IRQFLAGS
1475 If you say Y here, the lock dependency engine will do
1476 additional runtime checks to debug itself, at the price
1477 of more runtime overhead.
1479 config DEBUG_ATOMIC_SLEEP
1480 bool "Sleep inside atomic section checking"
1481 select PREEMPT_COUNT
1482 depends on DEBUG_KERNEL
1483 depends on !ARCH_NO_PREEMPT
1485 If you say Y here, various routines which may sleep will become very
1486 noisy if they are called inside atomic sections: when a spinlock is
1487 held, inside an rcu read side critical section, inside preempt disabled
1488 sections, inside an interrupt, etc...
1490 config DEBUG_LOCKING_API_SELFTESTS
1491 bool "Locking API boot-time self-tests"
1492 depends on DEBUG_KERNEL
1494 Say Y here if you want the kernel to run a short self-test during
1495 bootup. The self-test checks whether common types of locking bugs
1496 are detected by debugging mechanisms or not. (if you disable
1497 lock debugging then those bugs won't be detected of course.)
1498 The following locking APIs are covered: spinlocks, rwlocks,
1501 config LOCK_TORTURE_TEST
1502 tristate "torture tests for locking"
1503 depends on DEBUG_KERNEL
1506 This option provides a kernel module that runs torture tests
1507 on kernel locking primitives. The kernel module may be built
1508 after the fact on the running kernel to be tested, if desired.
1510 Say Y here if you want kernel locking-primitive torture tests
1511 to be built into the kernel.
1512 Say M if you want these torture tests to build as a module.
1513 Say N if you are unsure.
1515 config WW_MUTEX_SELFTEST
1516 tristate "Wait/wound mutex selftests"
1518 This option provides a kernel module that runs tests on the
1519 on the struct ww_mutex locking API.
1521 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1522 with this test harness.
1524 Say M if you want these self tests to build as a module.
1525 Say N if you are unsure.
1527 config SCF_TORTURE_TEST
1528 tristate "torture tests for smp_call_function*()"
1529 depends on DEBUG_KERNEL
1532 This option provides a kernel module that runs torture tests
1533 on the smp_call_function() family of primitives. The kernel
1534 module may be built after the fact on the running kernel to
1535 be tested, if desired.
1537 config CSD_LOCK_WAIT_DEBUG
1538 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1539 depends on DEBUG_KERNEL
1543 This option enables debug prints when CPUs are slow to respond
1544 to the smp_call_function*() IPI wrappers. These debug prints
1545 include the IPI handler function currently executing (if any)
1546 and relevant stack traces.
1549 prompt "Lock debugging: prove subsystem device_lock() correctness"
1550 depends on PROVE_LOCKING
1552 For subsystems that have instrumented their usage of the device_lock()
1553 with nested annotations, enable lock dependency checking. The locking
1554 hierarchy 'subclass' identifiers are not compatible across
1555 sub-systems, so only one can be enabled at a time.
1557 config PROVE_NVDIMM_LOCKING
1559 depends on LIBNVDIMM
1561 Enable lockdep to validate nd_device_lock() usage.
1563 config PROVE_CXL_LOCKING
1567 Enable lockdep to validate cxl_device_lock() usage.
1571 endmenu # lock debugging
1573 config TRACE_IRQFLAGS
1574 depends on TRACE_IRQFLAGS_SUPPORT
1577 Enables hooks to interrupt enabling and disabling for
1578 either tracing or lock debugging.
1580 config TRACE_IRQFLAGS_NMI
1582 depends on TRACE_IRQFLAGS
1583 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1585 config DEBUG_IRQFLAGS
1586 bool "Debug IRQ flag manipulation"
1588 Enables checks for potentially unsafe enabling or disabling of
1589 interrupts, such as calling raw_local_irq_restore() when interrupts
1593 bool "Stack backtrace support"
1594 depends on STACKTRACE_SUPPORT
1596 This option causes the kernel to create a /proc/pid/stack for
1597 every process, showing its current stack trace.
1598 It is also used by various kernel debugging features that require
1599 stack trace generation.
1601 config WARN_ALL_UNSEEDED_RANDOM
1602 bool "Warn for all uses of unseeded randomness"
1605 Some parts of the kernel contain bugs relating to their use of
1606 cryptographically secure random numbers before it's actually possible
1607 to generate those numbers securely. This setting ensures that these
1608 flaws don't go unnoticed, by enabling a message, should this ever
1609 occur. This will allow people with obscure setups to know when things
1610 are going wrong, so that they might contact developers about fixing
1613 Unfortunately, on some models of some architectures getting
1614 a fully seeded CRNG is extremely difficult, and so this can
1615 result in dmesg getting spammed for a surprisingly long
1616 time. This is really bad from a security perspective, and
1617 so architecture maintainers really need to do what they can
1618 to get the CRNG seeded sooner after the system is booted.
1619 However, since users cannot do anything actionable to
1620 address this, by default this option is disabled.
1622 Say Y here if you want to receive warnings for all uses of
1623 unseeded randomness. This will be of use primarily for
1624 those developers interested in improving the security of
1625 Linux kernels running on their architecture (or
1628 config DEBUG_KOBJECT
1629 bool "kobject debugging"
1630 depends on DEBUG_KERNEL
1632 If you say Y here, some extra kobject debugging messages will be sent
1635 config DEBUG_KOBJECT_RELEASE
1636 bool "kobject release debugging"
1637 depends on DEBUG_OBJECTS_TIMERS
1639 kobjects are reference counted objects. This means that their
1640 last reference count put is not predictable, and the kobject can
1641 live on past the point at which a driver decides to drop it's
1642 initial reference to the kobject gained on allocation. An
1643 example of this would be a struct device which has just been
1646 However, some buggy drivers assume that after such an operation,
1647 the memory backing the kobject can be immediately freed. This
1648 goes completely against the principles of a refcounted object.
1650 If you say Y here, the kernel will delay the release of kobjects
1651 on the last reference count to improve the visibility of this
1652 kind of kobject release bug.
1654 config HAVE_DEBUG_BUGVERBOSE
1657 menu "Debug kernel data structures"
1660 bool "Debug linked list manipulation"
1661 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1663 Enable this to turn on extended checks in the linked-list
1669 bool "Debug priority linked list manipulation"
1670 depends on DEBUG_KERNEL
1672 Enable this to turn on extended checks in the priority-ordered
1673 linked-list (plist) walking routines. This checks the entire
1674 list multiple times during each manipulation.
1679 bool "Debug SG table operations"
1680 depends on DEBUG_KERNEL
1682 Enable this to turn on checks on scatter-gather tables. This can
1683 help find problems with drivers that do not properly initialize
1688 config DEBUG_NOTIFIERS
1689 bool "Debug notifier call chains"
1690 depends on DEBUG_KERNEL
1692 Enable this to turn on sanity checking for notifier call chains.
1693 This is most useful for kernel developers to make sure that
1694 modules properly unregister themselves from notifier chains.
1695 This is a relatively cheap check but if you care about maximum
1698 config BUG_ON_DATA_CORRUPTION
1699 bool "Trigger a BUG when data corruption is detected"
1702 Select this option if the kernel should BUG when it encounters
1703 data corruption in kernel memory structures when they get checked
1710 config DEBUG_CREDENTIALS
1711 bool "Debug credential management"
1712 depends on DEBUG_KERNEL
1714 Enable this to turn on some debug checking for credential
1715 management. The additional code keeps track of the number of
1716 pointers from task_structs to any given cred struct, and checks to
1717 see that this number never exceeds the usage count of the cred
1720 Furthermore, if SELinux is enabled, this also checks that the
1721 security pointer in the cred struct is never seen to be invalid.
1725 source "kernel/rcu/Kconfig.debug"
1727 config DEBUG_WQ_FORCE_RR_CPU
1728 bool "Force round-robin CPU selection for unbound work items"
1729 depends on DEBUG_KERNEL
1732 Workqueue used to implicitly guarantee that work items queued
1733 without explicit CPU specified are put on the local CPU. This
1734 guarantee is no longer true and while local CPU is still
1735 preferred work items may be put on foreign CPUs. Kernel
1736 parameter "workqueue.debug_force_rr_cpu" is added to force
1737 round-robin CPU selection to flush out usages which depend on the
1738 now broken guarantee. This config option enables the debug
1739 feature by default. When enabled, memory and cache locality will
1742 config CPU_HOTPLUG_STATE_CONTROL
1743 bool "Enable CPU hotplug state control"
1744 depends on DEBUG_KERNEL
1745 depends on HOTPLUG_CPU
1748 Allows to write steps between "offline" and "online" to the CPUs
1749 sysfs target file so states can be stepped granular. This is a debug
1750 option for now as the hotplug machinery cannot be stopped and
1751 restarted at arbitrary points yet.
1753 Say N if your are unsure.
1756 bool "Latency measuring infrastructure"
1757 depends on DEBUG_KERNEL
1758 depends on STACKTRACE_SUPPORT
1760 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1766 Enable this option if you want to use the LatencyTOP tool
1767 to find out which userspace is blocking on what kernel operations.
1769 source "kernel/trace/Kconfig"
1771 config PROVIDE_OHCI1394_DMA_INIT
1772 bool "Remote debugging over FireWire early on boot"
1773 depends on PCI && X86
1775 If you want to debug problems which hang or crash the kernel early
1776 on boot and the crashing machine has a FireWire port, you can use
1777 this feature to remotely access the memory of the crashed machine
1778 over FireWire. This employs remote DMA as part of the OHCI1394
1779 specification which is now the standard for FireWire controllers.
1781 With remote DMA, you can monitor the printk buffer remotely using
1782 firescope and access all memory below 4GB using fireproxy from gdb.
1783 Even controlling a kernel debugger is possible using remote DMA.
1787 If ohci1394_dma=early is used as boot parameter, it will initialize
1788 all OHCI1394 controllers which are found in the PCI config space.
1790 As all changes to the FireWire bus such as enabling and disabling
1791 devices cause a bus reset and thereby disable remote DMA for all
1792 devices, be sure to have the cable plugged and FireWire enabled on
1793 the debugging host before booting the debug target for debugging.
1795 This code (~1k) is freed after boot. By then, the firewire stack
1796 in charge of the OHCI-1394 controllers should be used instead.
1798 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1800 source "samples/Kconfig"
1802 config ARCH_HAS_DEVMEM_IS_ALLOWED
1805 config STRICT_DEVMEM
1806 bool "Filter access to /dev/mem"
1807 depends on MMU && DEVMEM
1808 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1809 default y if PPC || X86 || ARM64
1811 If this option is disabled, you allow userspace (root) access to all
1812 of memory, including kernel and userspace memory. Accidental
1813 access to this is obviously disastrous, but specific access can
1814 be used by people debugging the kernel. Note that with PAT support
1815 enabled, even in this case there are restrictions on /dev/mem
1816 use due to the cache aliasing requirements.
1818 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1819 file only allows userspace access to PCI space and the BIOS code and
1820 data regions. This is sufficient for dosemu and X and all common
1825 config IO_STRICT_DEVMEM
1826 bool "Filter I/O access to /dev/mem"
1827 depends on STRICT_DEVMEM
1829 If this option is disabled, you allow userspace (root) access to all
1830 io-memory regardless of whether a driver is actively using that
1831 range. Accidental access to this is obviously disastrous, but
1832 specific access can be used by people debugging kernel drivers.
1834 If this option is switched on, the /dev/mem file only allows
1835 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1836 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1837 if the driver using a given range cannot be disabled.
1841 menu "$(SRCARCH) Debugging"
1843 source "arch/$(SRCARCH)/Kconfig.debug"
1847 menu "Kernel Testing and Coverage"
1849 source "lib/kunit/Kconfig"
1851 config NOTIFIER_ERROR_INJECTION
1852 tristate "Notifier error injection"
1853 depends on DEBUG_KERNEL
1856 This option provides the ability to inject artificial errors to
1857 specified notifier chain callbacks. It is useful to test the error
1858 handling of notifier call chain failures.
1862 config PM_NOTIFIER_ERROR_INJECT
1863 tristate "PM notifier error injection module"
1864 depends on PM && NOTIFIER_ERROR_INJECTION
1865 default m if PM_DEBUG
1867 This option provides the ability to inject artificial errors to
1868 PM notifier chain callbacks. It is controlled through debugfs
1869 interface /sys/kernel/debug/notifier-error-inject/pm
1871 If the notifier call chain should be failed with some events
1872 notified, write the error code to "actions/<notifier event>/error".
1874 Example: Inject PM suspend error (-12 = -ENOMEM)
1876 # cd /sys/kernel/debug/notifier-error-inject/pm/
1877 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1878 # echo mem > /sys/power/state
1879 bash: echo: write error: Cannot allocate memory
1881 To compile this code as a module, choose M here: the module will
1882 be called pm-notifier-error-inject.
1886 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1887 tristate "OF reconfig notifier error injection module"
1888 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1890 This option provides the ability to inject artificial errors to
1891 OF reconfig notifier chain callbacks. It is controlled
1892 through debugfs interface under
1893 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1895 If the notifier call chain should be failed with some events
1896 notified, write the error code to "actions/<notifier event>/error".
1898 To compile this code as a module, choose M here: the module will
1899 be called of-reconfig-notifier-error-inject.
1903 config NETDEV_NOTIFIER_ERROR_INJECT
1904 tristate "Netdev notifier error injection module"
1905 depends on NET && NOTIFIER_ERROR_INJECTION
1907 This option provides the ability to inject artificial errors to
1908 netdevice notifier chain callbacks. It is controlled through debugfs
1909 interface /sys/kernel/debug/notifier-error-inject/netdev
1911 If the notifier call chain should be failed with some events
1912 notified, write the error code to "actions/<notifier event>/error".
1914 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1916 # cd /sys/kernel/debug/notifier-error-inject/netdev
1917 # echo -22 > actions/NETDEV_CHANGEMTU/error
1918 # ip link set eth0 mtu 1024
1919 RTNETLINK answers: Invalid argument
1921 To compile this code as a module, choose M here: the module will
1922 be called netdev-notifier-error-inject.
1926 config FUNCTION_ERROR_INJECTION
1928 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1930 config FAULT_INJECTION
1931 bool "Fault-injection framework"
1932 depends on DEBUG_KERNEL
1934 Provide fault-injection framework.
1935 For more details, see Documentation/fault-injection/.
1938 bool "Fault-injection capability for kmalloc"
1939 depends on FAULT_INJECTION
1940 depends on SLAB || SLUB
1942 Provide fault-injection capability for kmalloc.
1944 config FAIL_PAGE_ALLOC
1945 bool "Fault-injection capability for alloc_pages()"
1946 depends on FAULT_INJECTION
1948 Provide fault-injection capability for alloc_pages().
1950 config FAULT_INJECTION_USERCOPY
1951 bool "Fault injection capability for usercopy functions"
1952 depends on FAULT_INJECTION
1954 Provides fault-injection capability to inject failures
1955 in usercopy functions (copy_from_user(), get_user(), ...).
1957 config FAIL_MAKE_REQUEST
1958 bool "Fault-injection capability for disk IO"
1959 depends on FAULT_INJECTION && BLOCK
1961 Provide fault-injection capability for disk IO.
1963 config FAIL_IO_TIMEOUT
1964 bool "Fault-injection capability for faking disk interrupts"
1965 depends on FAULT_INJECTION && BLOCK
1967 Provide fault-injection capability on end IO handling. This
1968 will make the block layer "forget" an interrupt as configured,
1969 thus exercising the error handling.
1971 Only works with drivers that use the generic timeout handling,
1972 for others it won't do anything.
1975 bool "Fault-injection capability for futexes"
1977 depends on FAULT_INJECTION && FUTEX
1979 Provide fault-injection capability for futexes.
1981 config FAULT_INJECTION_DEBUG_FS
1982 bool "Debugfs entries for fault-injection capabilities"
1983 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1985 Enable configuration of fault-injection capabilities via debugfs.
1987 config FAIL_FUNCTION
1988 bool "Fault-injection capability for functions"
1989 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1991 Provide function-based fault-injection capability.
1992 This will allow you to override a specific function with a return
1993 with given return value. As a result, function caller will see
1994 an error value and have to handle it. This is useful to test the
1995 error handling in various subsystems.
1997 config FAIL_MMC_REQUEST
1998 bool "Fault-injection capability for MMC IO"
1999 depends on FAULT_INJECTION_DEBUG_FS && MMC
2001 Provide fault-injection capability for MMC IO.
2002 This will make the mmc core return data errors. This is
2003 useful to test the error handling in the mmc block device
2004 and to test how the mmc host driver handles retries from
2008 bool "Fault-injection capability for SunRPC"
2009 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2011 Provide fault-injection capability for SunRPC and
2014 config FAULT_INJECTION_STACKTRACE_FILTER
2015 bool "stacktrace filter for fault-injection capabilities"
2016 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
2019 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2021 Provide stacktrace filter for fault-injection capabilities
2023 config ARCH_HAS_KCOV
2026 An architecture should select this when it can successfully
2027 build and run with CONFIG_KCOV. This typically requires
2028 disabling instrumentation for some early boot code.
2030 config CC_HAS_SANCOV_TRACE_PC
2031 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2035 bool "Code coverage for fuzzing"
2036 depends on ARCH_HAS_KCOV
2037 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2038 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2039 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
2041 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2042 select OBJTOOL if HAVE_NOINSTR_HACK
2044 KCOV exposes kernel code coverage information in a form suitable
2045 for coverage-guided fuzzing (randomized testing).
2047 If RANDOMIZE_BASE is enabled, PC values will not be stable across
2048 different machines and across reboots. If you need stable PC values,
2049 disable RANDOMIZE_BASE.
2051 For more details, see Documentation/dev-tools/kcov.rst.
2053 config KCOV_ENABLE_COMPARISONS
2054 bool "Enable comparison operands collection by KCOV"
2056 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2058 KCOV also exposes operands of every comparison in the instrumented
2059 code along with operand sizes and PCs of the comparison instructions.
2060 These operands can be used by fuzzing engines to improve the quality
2061 of fuzzing coverage.
2063 config KCOV_INSTRUMENT_ALL
2064 bool "Instrument all code by default"
2068 If you are doing generic system call fuzzing (like e.g. syzkaller),
2069 then you will want to instrument the whole kernel and you should
2070 say y here. If you are doing more targeted fuzzing (like e.g.
2071 filesystem fuzzing with AFL) then you will want to enable coverage
2072 for more specific subsets of files, and should say n here.
2074 config KCOV_IRQ_AREA_SIZE
2075 hex "Size of interrupt coverage collection area in words"
2079 KCOV uses preallocated per-cpu areas to collect coverage from
2080 soft interrupts. This specifies the size of those areas in the
2081 number of unsigned long words.
2083 menuconfig RUNTIME_TESTING_MENU
2084 bool "Runtime Testing"
2087 if RUNTIME_TESTING_MENU
2090 tristate "Linux Kernel Dump Test Tool Module"
2093 This module enables testing of the different dumping mechanisms by
2094 inducing system failures at predefined crash points.
2095 If you don't need it: say N
2096 Choose M here to compile this code as a module. The module will be
2099 Documentation on how to use the module can be found in
2100 Documentation/fault-injection/provoke-crashes.rst
2102 config TEST_LIST_SORT
2103 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2105 default KUNIT_ALL_TESTS
2107 Enable this to turn on 'list_sort()' function test. This test is
2108 executed only once during system boot (so affects only boot time),
2109 or at module load time.
2113 config TEST_MIN_HEAP
2114 tristate "Min heap test"
2115 depends on DEBUG_KERNEL || m
2117 Enable this to turn on min heap function tests. This test is
2118 executed only once during system boot (so affects only boot time),
2119 or at module load time.
2124 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2126 default KUNIT_ALL_TESTS
2128 This option enables the self-test function of 'sort()' at boot,
2129 or at module load time.
2134 tristate "64bit/32bit division and modulo test"
2135 depends on DEBUG_KERNEL || m
2137 Enable this to turn on 'do_div()' function test. This test is
2138 executed only once during system boot (so affects only boot time),
2139 or at module load time.
2143 config KPROBES_SANITY_TEST
2144 tristate "Kprobes sanity tests"
2145 depends on DEBUG_KERNEL
2149 This option provides for testing basic kprobes functionality on
2150 boot. Samples of kprobe and kretprobe are inserted and
2151 verified for functionality.
2153 Say N if you are unsure.
2155 config FPROBE_SANITY_TEST
2156 bool "Self test for fprobe"
2157 depends on DEBUG_KERNEL
2161 This option will enable testing the fprobe when the system boot.
2162 A series of tests are made to verify that the fprobe is functioning
2165 Say N if you are unsure.
2167 config BACKTRACE_SELF_TEST
2168 tristate "Self test for the backtrace code"
2169 depends on DEBUG_KERNEL
2171 This option provides a kernel module that can be used to test
2172 the kernel stack backtrace code. This option is not useful
2173 for distributions or general kernels, but only for kernel
2174 developers working on architecture code.
2176 Note that if you want to also test saved backtraces, you will
2177 have to enable STACKTRACE as well.
2179 Say N if you are unsure.
2181 config TEST_REF_TRACKER
2182 tristate "Self test for reference tracker"
2183 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2186 This option provides a kernel module performing tests
2187 using reference tracker infrastructure.
2189 Say N if you are unsure.
2192 tristate "Red-Black tree test"
2193 depends on DEBUG_KERNEL
2195 A benchmark measuring the performance of the rbtree library.
2196 Also includes rbtree invariant checks.
2198 config REED_SOLOMON_TEST
2199 tristate "Reed-Solomon library test"
2200 depends on DEBUG_KERNEL || m
2202 select REED_SOLOMON_ENC16
2203 select REED_SOLOMON_DEC16
2205 This option enables the self-test function of rslib at boot,
2206 or at module load time.
2210 config INTERVAL_TREE_TEST
2211 tristate "Interval tree test"
2212 depends on DEBUG_KERNEL
2213 select INTERVAL_TREE
2215 A benchmark measuring the performance of the interval tree library
2218 tristate "Per cpu operations test"
2219 depends on m && DEBUG_KERNEL
2221 Enable this option to build test module which validates per-cpu
2226 config ATOMIC64_SELFTEST
2227 tristate "Perform an atomic64_t self-test"
2229 Enable this option to test the atomic64_t functions at boot or
2230 at module load time.
2234 config ASYNC_RAID6_TEST
2235 tristate "Self test for hardware accelerated raid6 recovery"
2236 depends on ASYNC_RAID6_RECOV
2239 This is a one-shot self test that permutes through the
2240 recovery of all the possible two disk failure scenarios for a
2241 N-disk array. Recovery is performed with the asynchronous
2242 raid6 recovery routines, and will optionally use an offload
2243 engine if one is available.
2248 tristate "Test functions located in the hexdump module at runtime"
2250 config STRING_SELFTEST
2251 tristate "Test string functions at runtime"
2253 config TEST_STRING_HELPERS
2254 tristate "Test functions located in the string_helpers module at runtime"
2257 tristate "Test strscpy*() family of functions at runtime"
2260 tristate "Test kstrto*() family of functions at runtime"
2263 tristate "Test printf() family of functions at runtime"
2266 tristate "Test scanf() family of functions at runtime"
2269 tristate "Test bitmap_*() family of functions at runtime"
2271 Enable this option to test the bitmap functions at boot.
2276 tristate "Test functions located in the uuid module at runtime"
2279 tristate "Test the XArray code at runtime"
2281 config TEST_RHASHTABLE
2282 tristate "Perform selftest on resizable hash table"
2284 Enable this option to test the rhashtable functions at boot.
2289 tristate "Perform selftest on siphash functions"
2291 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2292 functions on boot (or module load).
2294 This is intended to help people writing architecture-specific
2295 optimized versions. If unsure, say N.
2298 tristate "Perform selftest on IDA functions"
2301 tristate "Perform selftest on priority array manager"
2304 Enable this option to test priority array manager on boot
2309 config TEST_IRQ_TIMINGS
2310 bool "IRQ timings selftest"
2311 depends on IRQ_TIMINGS
2313 Enable this option to test the irq timings code on boot.
2318 tristate "Test module loading with 'hello world' module"
2321 This builds the "test_module" module that emits "Hello, world"
2322 on printk when loaded. It is designed to be used for basic
2323 evaluation of the module loading subsystem (for example when
2324 validating module verification). It lacks any extra dependencies,
2325 and will not normally be loaded by the system unless explicitly
2331 tristate "Test module for compilation of bitops operations"
2334 This builds the "test_bitops" module that is much like the
2335 TEST_LKM module except that it does a basic exercise of the
2336 set/clear_bit macros and get_count_order/long to make sure there are
2337 no compiler warnings from C=1 sparse checker or -Wextra
2338 compilations. It has no dependencies and doesn't run or load unless
2339 explicitly requested by name. for example: modprobe test_bitops.
2344 tristate "Test module for stress/performance analysis of vmalloc allocator"
2349 This builds the "test_vmalloc" module that should be used for
2350 stress and performance analysis. So, any new change for vmalloc
2351 subsystem can be evaluated from performance and stability point
2356 config TEST_USER_COPY
2357 tristate "Test user/kernel boundary protections"
2360 This builds the "test_user_copy" module that runs sanity checks
2361 on the copy_to/from_user infrastructure, making sure basic
2362 user/kernel boundary testing is working. If it fails to load,
2363 a regression has been detected in the user/kernel memory boundary
2369 tristate "Test BPF filter functionality"
2372 This builds the "test_bpf" module that runs various test vectors
2373 against the BPF interpreter or BPF JIT compiler depending on the
2374 current setting. This is in particular useful for BPF JIT compiler
2375 development, but also to run regression tests against changes in
2376 the interpreter code. It also enables test stubs for eBPF maps and
2377 verifier used by user space verifier testsuite.
2381 config TEST_BLACKHOLE_DEV
2382 tristate "Test blackhole netdev functionality"
2385 This builds the "test_blackhole_dev" module that validates the
2386 data path through this blackhole netdev.
2390 config FIND_BIT_BENCHMARK
2391 tristate "Test find_bit functions"
2393 This builds the "test_find_bit" module that measure find_*_bit()
2394 functions performance.
2398 config TEST_FIRMWARE
2399 tristate "Test firmware loading via userspace interface"
2400 depends on FW_LOADER
2402 This builds the "test_firmware" module that creates a userspace
2403 interface for testing firmware loading. This can be used to
2404 control the triggering of firmware loading without needing an
2405 actual firmware-using device. The contents can be rechecked by
2411 tristate "sysctl test driver"
2412 depends on PROC_SYSCTL
2414 This builds the "test_sysctl" module. This driver enables to test the
2415 proc sysctl interfaces available to drivers safely without affecting
2416 production knobs which might alter system functionality.
2420 config BITFIELD_KUNIT
2421 tristate "KUnit test bitfield functions at runtime"
2424 Enable this option to test the bitfield functions at boot.
2426 KUnit tests run during boot and output the results to the debug log
2427 in TAP format (http://testanything.org/). Only useful for kernel devs
2428 running the KUnit test harness, and not intended for inclusion into a
2431 For more information on KUnit and unit tests in general please refer
2432 to the KUnit documentation in Documentation/dev-tools/kunit/.
2436 config HASH_KUNIT_TEST
2437 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2439 default KUNIT_ALL_TESTS
2441 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2442 integer (<linux/hash.h>) hash functions on boot.
2444 KUnit tests run during boot and output the results to the debug log
2445 in TAP format (https://testanything.org/). Only useful for kernel devs
2446 running the KUnit test harness, and not intended for inclusion into a
2449 For more information on KUnit and unit tests in general please refer
2450 to the KUnit documentation in Documentation/dev-tools/kunit/.
2452 This is intended to help people writing architecture-specific
2453 optimized versions. If unsure, say N.
2455 config RESOURCE_KUNIT_TEST
2456 tristate "KUnit test for resource API"
2459 This builds the resource API unit test.
2460 Tests the logic of API provided by resource.c and ioport.h.
2461 For more information on KUnit and unit tests in general please refer
2462 to the KUnit documentation in Documentation/dev-tools/kunit/.
2466 config SYSCTL_KUNIT_TEST
2467 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2469 default KUNIT_ALL_TESTS
2471 This builds the proc sysctl unit test, which runs on boot.
2472 Tests the API contract and implementation correctness of sysctl.
2473 For more information on KUnit and unit tests in general please refer
2474 to the KUnit documentation in Documentation/dev-tools/kunit/.
2478 config LIST_KUNIT_TEST
2479 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2481 default KUNIT_ALL_TESTS
2483 This builds the linked list KUnit test suite.
2484 It tests that the API and basic functionality of the list_head type
2485 and associated macros.
2487 KUnit tests run during boot and output the results to the debug log
2488 in TAP format (https://testanything.org/). Only useful for kernel devs
2489 running the KUnit test harness, and not intended for inclusion into a
2492 For more information on KUnit and unit tests in general please refer
2493 to the KUnit documentation in Documentation/dev-tools/kunit/.
2497 config LINEAR_RANGES_TEST
2498 tristate "KUnit test for linear_ranges"
2500 select LINEAR_RANGES
2502 This builds the linear_ranges unit test, which runs on boot.
2503 Tests the linear_ranges logic correctness.
2504 For more information on KUnit and unit tests in general please refer
2505 to the KUnit documentation in Documentation/dev-tools/kunit/.
2509 config CMDLINE_KUNIT_TEST
2510 tristate "KUnit test for cmdline API"
2513 This builds the cmdline API unit test.
2514 Tests the logic of API provided by cmdline.c.
2515 For more information on KUnit and unit tests in general please refer
2516 to the KUnit documentation in Documentation/dev-tools/kunit/.
2521 tristate "KUnit test for bits.h"
2524 This builds the bits unit test.
2525 Tests the logic of macros defined in bits.h.
2526 For more information on KUnit and unit tests in general please refer
2527 to the KUnit documentation in Documentation/dev-tools/kunit/.
2531 config SLUB_KUNIT_TEST
2532 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2533 depends on SLUB_DEBUG && KUNIT
2534 default KUNIT_ALL_TESTS
2536 This builds SLUB allocator unit test.
2537 Tests SLUB cache debugging functionality.
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 RATIONAL_KUNIT_TEST
2544 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2545 depends on KUNIT && RATIONAL
2546 default KUNIT_ALL_TESTS
2548 This builds the rational math unit test.
2549 For more information on KUnit and unit tests in general please refer
2550 to the KUnit documentation in Documentation/dev-tools/kunit/.
2554 config MEMCPY_KUNIT_TEST
2555 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2557 default KUNIT_ALL_TESTS
2559 Builds unit tests for memcpy(), memmove(), and memset() functions.
2560 For more information on KUnit and unit tests in general please refer
2561 to the KUnit documentation in Documentation/dev-tools/kunit/.
2565 config OVERFLOW_KUNIT_TEST
2566 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2568 default KUNIT_ALL_TESTS
2570 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2573 For more information on KUnit and unit tests in general please refer
2574 to the KUnit documentation in Documentation/dev-tools/kunit/.
2578 config STACKINIT_KUNIT_TEST
2579 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2581 default KUNIT_ALL_TESTS
2583 Test if the kernel is zero-initializing stack variables and
2584 padding. Coverage is controlled by compiler flags,
2585 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2586 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2587 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2590 tristate "udelay test driver"
2592 This builds the "udelay_test" module that helps to make sure
2593 that udelay() is working properly.
2597 config TEST_STATIC_KEYS
2598 tristate "Test static keys"
2601 Test the static key interfaces.
2606 tristate "kmod stress tester"
2608 depends on NETDEVICES && NET_CORE && INET # for TUN
2610 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2616 Test the kernel's module loading mechanism: kmod. kmod implements
2617 support to load modules using the Linux kernel's usermode helper.
2618 This test provides a series of tests against kmod.
2620 Although technically you can either build test_kmod as a module or
2621 into the kernel we disallow building it into the kernel since
2622 it stress tests request_module() and this will very likely cause
2623 some issues by taking over precious threads available from other
2624 module load requests, ultimately this could be fatal.
2628 tools/testing/selftests/kmod/kmod.sh --help
2632 config TEST_DEBUG_VIRTUAL
2633 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2634 depends on DEBUG_VIRTUAL
2636 Test the kernel's ability to detect incorrect calls to
2637 virt_to_phys() done against the non-linear part of the
2638 kernel's virtual address map.
2642 config TEST_MEMCAT_P
2643 tristate "Test memcat_p() helper function"
2645 Test the memcat_p() helper for correctly merging two
2646 pointer arrays together.
2650 config TEST_LIVEPATCH
2651 tristate "Test livepatching"
2653 depends on DYNAMIC_DEBUG
2654 depends on LIVEPATCH
2657 Test kernel livepatching features for correctness. The tests will
2658 load test modules that will be livepatched in various scenarios.
2660 To run all the livepatching tests:
2662 make -C tools/testing/selftests TARGETS=livepatch run_tests
2664 Alternatively, individual tests may be invoked:
2666 tools/testing/selftests/livepatch/test-callbacks.sh
2667 tools/testing/selftests/livepatch/test-livepatch.sh
2668 tools/testing/selftests/livepatch/test-shadow-vars.sh
2673 tristate "Perform selftest on object aggreration manager"
2677 Enable this option to test object aggregation manager on boot
2681 tristate "Test heap/page initialization"
2683 Test if the kernel is zero-initializing heap and page allocations.
2684 This can be useful to test init_on_alloc and init_on_free features.
2689 tristate "Test HMM (Heterogeneous Memory Management)"
2690 depends on TRANSPARENT_HUGEPAGE
2691 depends on DEVICE_PRIVATE
2695 This is a pseudo device driver solely for testing HMM.
2696 Say M here if you want to build the HMM test module.
2697 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2701 config TEST_FREE_PAGES
2702 tristate "Test freeing pages"
2704 Test that a memory leak does not occur due to a race between
2705 freeing a block of pages and a speculative page reference.
2706 Loading this module is safe if your kernel has the bug fixed.
2707 If the bug is not fixed, it will leak gigabytes of memory and
2708 probably OOM your system.
2711 tristate "Test floating point operations in kernel space"
2712 depends on X86 && !KCOV_INSTRUMENT_ALL
2714 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2715 which will trigger a sequence of floating point operations. This is used
2716 for self-testing floating point control register setting in
2721 config TEST_CLOCKSOURCE_WATCHDOG
2722 tristate "Test clocksource watchdog in kernel space"
2723 depends on CLOCKSOURCE_WATCHDOG
2725 Enable this option to create a kernel module that will trigger
2726 a test of the clocksource watchdog. This module may be loaded
2727 via modprobe or insmod in which case it will run upon being
2728 loaded, or it may be built in, in which case it will run
2733 endif # RUNTIME_TESTING_MENU
2735 config ARCH_USE_MEMTEST
2738 An architecture should select this when it uses early_memtest()
2739 during boot process.
2743 depends on ARCH_USE_MEMTEST
2745 This option adds a kernel parameter 'memtest', which allows memtest
2746 to be set and executed.
2747 memtest=0, mean disabled; -- default
2748 memtest=1, mean do 1 test pattern;
2750 memtest=17, mean do 17 test patterns.
2751 If you are unsure how to answer this question, answer N.
2755 config HYPERV_TESTING
2756 bool "Microsoft Hyper-V driver testing"
2758 depends on HYPERV && DEBUG_FS
2760 Select this option to enable Hyper-V vmbus testing.
2762 endmenu # "Kernel Testing and Coverage"
2764 source "Documentation/Kconfig"
2766 endmenu # Kernel hacking
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