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.
234 # Clang is known to generate .{s,u}leb128 with symbol deltas with DWARF5, which
235 # some targets may not support: https://sourceware.org/bugzilla/show_bug.cgi?id=27215
236 config AS_HAS_NON_CONST_LEB128
237 def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:)
240 prompt "Debug information"
241 depends on DEBUG_KERNEL
243 Selecting something other than "None" results in a kernel image
244 that will include debugging info resulting in a larger kernel image.
245 This adds debug symbols to the kernel and modules (gcc -g), and
246 is needed if you intend to use kernel crashdump or binary object
247 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
249 Choose which version of DWARF debug info to emit. If unsure,
250 select "Toolchain default".
252 config DEBUG_INFO_NONE
253 bool "Disable debug information"
255 Do not build the kernel with debugging information, which will
256 result in a faster and smaller build.
258 config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
259 bool "Rely on the toolchain's implicit default DWARF version"
261 depends on !CC_IS_CLANG || AS_IS_LLVM || CLANG_VERSION < 140000 || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128)
263 The implicit default version of DWARF debug info produced by a
264 toolchain changes over time.
266 This can break consumers of the debug info that haven't upgraded to
267 support newer revisions, and prevent testing newer versions, but
268 those should be less common scenarios.
270 config DEBUG_INFO_DWARF4
271 bool "Generate DWARF Version 4 debuginfo"
273 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)
275 Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2
276 if using clang without clang's integrated assembler, and gdb 7.0+.
278 If you have consumers of DWARF debug info that are not ready for
279 newer revisions of DWARF, you may wish to choose this or have your
282 config DEBUG_INFO_DWARF5
283 bool "Generate DWARF Version 5 debuginfo"
285 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128)
287 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
288 5.0+ accepts the -gdwarf-5 flag but only had partial support for some
289 draft features until 7.0), and gdb 8.0+.
291 Changes to the structure of debug info in Version 5 allow for around
292 15-18% savings in resulting image and debug info section sizes as
293 compared to DWARF Version 4. DWARF Version 5 standardizes previous
294 extensions such as accelerators for symbol indexing and the format
295 for fission (.dwo/.dwp) files. Users may not want to select this
296 config if they rely on tooling that has not yet been updated to
297 support DWARF Version 5.
299 endchoice # "Debug information"
303 config DEBUG_INFO_REDUCED
304 bool "Reduce debugging information"
306 If you say Y here gcc is instructed to generate less debugging
307 information for structure types. This means that tools that
308 need full debugging information (like kgdb or systemtap) won't
309 be happy. But if you merely need debugging information to
310 resolve line numbers there is no loss. Advantage is that
311 build directory object sizes shrink dramatically over a full
312 DEBUG_INFO build and compile times are reduced too.
313 Only works with newer gcc versions.
315 config DEBUG_INFO_COMPRESSED
316 bool "Compressed debugging information"
317 depends on $(cc-option,-gz=zlib)
318 depends on $(ld-option,--compress-debug-sections=zlib)
320 Compress the debug information using zlib. Requires GCC 5.0+ or Clang
321 5.0+, binutils 2.26+, and zlib.
323 Users of dpkg-deb via scripts/package/builddeb may find an increase in
324 size of their debug .deb packages with this config set, due to the
325 debug info being compressed with zlib, then the object files being
326 recompressed with a different compression scheme. But this is still
327 preferable to setting $KDEB_COMPRESS to "none" which would be even
330 config DEBUG_INFO_SPLIT
331 bool "Produce split debuginfo in .dwo files"
332 depends on $(cc-option,-gsplit-dwarf)
334 Generate debug info into separate .dwo files. This significantly
335 reduces the build directory size for builds with DEBUG_INFO,
336 because it stores the information only once on disk in .dwo
337 files instead of multiple times in object files and executables.
338 In addition the debug information is also compressed.
340 Requires recent gcc (4.7+) and recent gdb/binutils.
341 Any tool that packages or reads debug information would need
342 to know about the .dwo files and include them.
343 Incompatible with older versions of ccache.
345 config DEBUG_INFO_BTF
346 bool "Generate BTF typeinfo"
347 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
348 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
349 depends on BPF_SYSCALL
350 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121
352 Generate deduplicated BTF type information from DWARF debug info.
353 Turning this on expects presence of pahole tool, which will convert
354 DWARF type info into equivalent deduplicated BTF type info.
356 config PAHOLE_HAS_SPLIT_BTF
357 def_bool PAHOLE_VERSION >= 119
359 config PAHOLE_HAS_BTF_TAG
360 def_bool PAHOLE_VERSION >= 123
361 depends on CC_IS_CLANG
363 Decide whether pahole emits btf_tag attributes (btf_type_tag and
364 btf_decl_tag) or not. Currently only clang compiler implements
365 these attributes, so make the config depend on CC_IS_CLANG.
367 config DEBUG_INFO_BTF_MODULES
369 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
371 Generate compact split BTF type information for kernel modules.
373 config MODULE_ALLOW_BTF_MISMATCH
374 bool "Allow loading modules with non-matching BTF type info"
375 depends on DEBUG_INFO_BTF_MODULES
377 For modules whose split BTF does not match vmlinux, load without
378 BTF rather than refusing to load. The default behavior with
379 module BTF enabled is to reject modules with such mismatches;
380 this option will still load module BTF where possible but ignore
381 it when a mismatch is found.
384 bool "Provide GDB scripts for kernel debugging"
386 This creates the required links to GDB helper scripts in the
387 build directory. If you load vmlinux into gdb, the helper
388 scripts will be automatically imported by gdb as well, and
389 additional functions are available to analyze a Linux kernel
390 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
396 int "Warn for stack frames larger than"
398 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
399 default 2048 if PARISC
400 default 1536 if (!64BIT && XTENSA)
401 default 1024 if !64BIT
402 default 2048 if 64BIT
404 Tell gcc to warn at build time for stack frames larger than this.
405 Setting this too low will cause a lot of warnings.
406 Setting it to 0 disables the warning.
408 config STRIP_ASM_SYMS
409 bool "Strip assembler-generated symbols during link"
412 Strip internal assembler-generated symbols during a link (symbols
413 that look like '.Lxxx') so they don't pollute the output of
414 get_wchan() and suchlike.
417 bool "Generate readable assembler code"
418 depends on DEBUG_KERNEL
421 Disable some compiler optimizations that tend to generate human unreadable
422 assembler output. This may make the kernel slightly slower, but it helps
423 to keep kernel developers who have to stare a lot at assembler listings
426 config HEADERS_INSTALL
427 bool "Install uapi headers to usr/include"
430 This option will install uapi headers (headers exported to user-space)
431 into the usr/include directory for use during the kernel build.
432 This is unneeded for building the kernel itself, but needed for some
433 user-space program samples. It is also needed by some features such
434 as uapi header sanity checks.
436 config DEBUG_SECTION_MISMATCH
437 bool "Enable full Section mismatch analysis"
440 The section mismatch analysis checks if there are illegal
441 references from one section to another section.
442 During linktime or runtime, some sections are dropped;
443 any use of code/data previously in these sections would
444 most likely result in an oops.
445 In the code, functions and variables are annotated with
446 __init,, etc. (see the full list in include/linux/init.h),
447 which results in the code/data being placed in specific sections.
448 The section mismatch analysis is always performed after a full
449 kernel build, and enabling this option causes the following
450 additional step to occur:
451 - Add the option -fno-inline-functions-called-once to gcc commands.
452 When inlining a function annotated with __init in a non-init
453 function, we would lose the section information and thus
454 the analysis would not catch the illegal reference.
455 This option tells gcc to inline less (but it does result in
458 config SECTION_MISMATCH_WARN_ONLY
459 bool "Make section mismatch errors non-fatal"
462 If you say N here, the build process will fail if there are any
463 section mismatch, instead of just throwing warnings.
467 config DEBUG_FORCE_FUNCTION_ALIGN_64B
468 bool "Force all function address 64B aligned"
469 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC)
471 There are cases that a commit from one domain changes the function
472 address alignment of other domains, and cause magic performance
473 bump (regression or improvement). Enable this option will help to
474 verify if the bump is caused by function alignment changes, while
475 it will slightly increase the kernel size and affect icache usage.
477 It is mainly for debug and performance tuning use.
480 # Select this config option from the architecture Kconfig, if it
481 # is preferred to always offer frame pointers as a config
482 # option on the architecture (regardless of KERNEL_DEBUG):
484 config ARCH_WANT_FRAME_POINTERS
488 bool "Compile the kernel with frame pointers"
489 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
490 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
492 If you say Y here the resulting kernel image will be slightly
493 larger and slower, but it gives very useful debugging information
494 in case of kernel bugs. (precise oopses/stacktraces/warnings)
499 config STACK_VALIDATION
500 bool "Compile-time stack metadata validation"
501 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
505 Validate frame pointer rules at compile-time. This helps ensure that
506 runtime stack traces are more reliable.
508 For more information, see
509 tools/objtool/Documentation/objtool.txt.
511 config NOINSTR_VALIDATION
513 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
518 bool "Generate vmlinux.map file when linking"
521 Selecting this option will pass "-Map=vmlinux.map" to ld
522 when linking vmlinux. That file can be useful for verifying
523 and debugging magic section games, and for seeing which
524 pieces of code get eliminated with
525 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
527 config DEBUG_FORCE_WEAK_PER_CPU
528 bool "Force weak per-cpu definitions"
529 depends on DEBUG_KERNEL
531 s390 and alpha require percpu variables in modules to be
532 defined weak to work around addressing range issue which
533 puts the following two restrictions on percpu variable
536 1. percpu symbols must be unique whether static or not
537 2. percpu variables can't be defined inside a function
539 To ensure that generic code follows the above rules, this
540 option forces all percpu variables to be defined as weak.
542 endmenu # "Compiler options"
544 menu "Generic Kernel Debugging Instruments"
547 bool "Magic SysRq key"
550 If you say Y here, you will have some control over the system even
551 if the system crashes for example during kernel debugging (e.g., you
552 will be able to flush the buffer cache to disk, reboot the system
553 immediately or dump some status information). This is accomplished
554 by pressing various keys while holding SysRq (Alt+PrintScreen). It
555 also works on a serial console (on PC hardware at least), if you
556 send a BREAK and then within 5 seconds a command keypress. The
557 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
558 Don't say Y unless you really know what this hack does.
560 config MAGIC_SYSRQ_DEFAULT_ENABLE
561 hex "Enable magic SysRq key functions by default"
562 depends on MAGIC_SYSRQ
565 Specifies which SysRq key functions are enabled by default.
566 This may be set to 1 or 0 to enable or disable them all, or
567 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
569 config MAGIC_SYSRQ_SERIAL
570 bool "Enable magic SysRq key over serial"
571 depends on MAGIC_SYSRQ
574 Many embedded boards have a disconnected TTL level serial which can
575 generate some garbage that can lead to spurious false sysrq detects.
576 This option allows you to decide whether you want to enable the
579 config MAGIC_SYSRQ_SERIAL_SEQUENCE
580 string "Char sequence that enables magic SysRq over serial"
581 depends on MAGIC_SYSRQ_SERIAL
584 Specifies a sequence of characters that can follow BREAK to enable
585 SysRq on a serial console.
587 If unsure, leave an empty string and the option will not be enabled.
590 bool "Debug Filesystem"
592 debugfs is a virtual file system that kernel developers use to put
593 debugging files into. Enable this option to be able to read and
594 write to these files.
596 For detailed documentation on the debugfs API, see
597 Documentation/filesystems/.
602 prompt "Debugfs default access"
604 default DEBUG_FS_ALLOW_ALL
606 This selects the default access restrictions for debugfs.
607 It can be overridden with kernel command line option
608 debugfs=[on,no-mount,off]. The restrictions apply for API access
609 and filesystem registration.
611 config DEBUG_FS_ALLOW_ALL
614 No restrictions apply. Both API and filesystem registration
615 is on. This is the normal default operation.
617 config DEBUG_FS_DISALLOW_MOUNT
618 bool "Do not register debugfs as filesystem"
620 The API is open but filesystem is not loaded. Clients can still do
621 their work and read with debug tools that do not need
624 config DEBUG_FS_ALLOW_NONE
627 Access is off. Clients get -PERM when trying to create nodes in
628 debugfs tree and debugfs is not registered as a filesystem.
629 Client can then back-off or continue without debugfs access.
633 source "lib/Kconfig.kgdb"
634 source "lib/Kconfig.ubsan"
635 source "lib/Kconfig.kcsan"
639 menu "Networking Debugging"
641 source "net/Kconfig.debug"
643 endmenu # "Networking Debugging"
645 menu "Memory Debugging"
647 source "mm/Kconfig.debug"
650 bool "Debug object operations"
651 depends on DEBUG_KERNEL
653 If you say Y here, additional code will be inserted into the
654 kernel to track the life time of various objects and validate
655 the operations on those objects.
657 config DEBUG_OBJECTS_SELFTEST
658 bool "Debug objects selftest"
659 depends on DEBUG_OBJECTS
661 This enables the selftest of the object debug code.
663 config DEBUG_OBJECTS_FREE
664 bool "Debug objects in freed memory"
665 depends on DEBUG_OBJECTS
667 This enables checks whether a k/v free operation frees an area
668 which contains an object which has not been deactivated
669 properly. This can make kmalloc/kfree-intensive workloads
672 config DEBUG_OBJECTS_TIMERS
673 bool "Debug timer objects"
674 depends on DEBUG_OBJECTS
676 If you say Y here, additional code will be inserted into the
677 timer routines to track the life time of timer objects and
678 validate the timer operations.
680 config DEBUG_OBJECTS_WORK
681 bool "Debug work objects"
682 depends on DEBUG_OBJECTS
684 If you say Y here, additional code will be inserted into the
685 work queue routines to track the life time of work objects and
686 validate the work operations.
688 config DEBUG_OBJECTS_RCU_HEAD
689 bool "Debug RCU callbacks objects"
690 depends on DEBUG_OBJECTS
692 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
694 config DEBUG_OBJECTS_PERCPU_COUNTER
695 bool "Debug percpu counter objects"
696 depends on DEBUG_OBJECTS
698 If you say Y here, additional code will be inserted into the
699 percpu counter routines to track the life time of percpu counter
700 objects and validate the percpu counter operations.
702 config DEBUG_OBJECTS_ENABLE_DEFAULT
703 int "debug_objects bootup default value (0-1)"
706 depends on DEBUG_OBJECTS
708 Debug objects boot parameter default value
710 config SHRINKER_DEBUG
711 bool "Enable shrinker debugging support"
714 Say Y to enable the shrinker debugfs interface which provides
715 visibility into the kernel memory shrinkers subsystem.
716 Disable it to avoid an extra memory footprint.
718 config HAVE_DEBUG_KMEMLEAK
721 config DEBUG_KMEMLEAK
722 bool "Kernel memory leak detector"
723 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
725 select STACKTRACE if STACKTRACE_SUPPORT
729 Say Y here if you want to enable the memory leak
730 detector. The memory allocation/freeing is traced in a way
731 similar to the Boehm's conservative garbage collector, the
732 difference being that the orphan objects are not freed but
733 only shown in /sys/kernel/debug/kmemleak. Enabling this
734 feature will introduce an overhead to memory
735 allocations. See Documentation/dev-tools/kmemleak.rst for more
738 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
739 of finding leaks due to the slab objects poisoning.
741 In order to access the kmemleak file, debugfs needs to be
742 mounted (usually at /sys/kernel/debug).
744 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
745 int "Kmemleak memory pool size"
746 depends on DEBUG_KMEMLEAK
750 Kmemleak must track all the memory allocations to avoid
751 reporting false positives. Since memory may be allocated or
752 freed before kmemleak is fully initialised, use a static pool
753 of metadata objects to track such callbacks. After kmemleak is
754 fully initialised, this memory pool acts as an emergency one
755 if slab allocations fail.
757 config DEBUG_KMEMLEAK_TEST
758 tristate "Simple test for the kernel memory leak detector"
759 depends on DEBUG_KMEMLEAK && m
761 This option enables a module that explicitly leaks memory.
765 config DEBUG_KMEMLEAK_DEFAULT_OFF
766 bool "Default kmemleak to off"
767 depends on DEBUG_KMEMLEAK
769 Say Y here to disable kmemleak by default. It can then be enabled
770 on the command line via kmemleak=on.
772 config DEBUG_KMEMLEAK_AUTO_SCAN
773 bool "Enable kmemleak auto scan thread on boot up"
775 depends on DEBUG_KMEMLEAK
777 Depending on the cpu, kmemleak scan may be cpu intensive and can
778 stall user tasks at times. This option enables/disables automatic
779 kmemleak scan at boot up.
781 Say N here to disable kmemleak auto scan thread to stop automatic
782 scanning. Disabling this option disables automatic reporting of
787 config DEBUG_STACK_USAGE
788 bool "Stack utilization instrumentation"
789 depends on DEBUG_KERNEL && !IA64
791 Enables the display of the minimum amount of free stack which each
792 task has ever had available in the sysrq-T and sysrq-P debug output.
794 This option will slow down process creation somewhat.
796 config SCHED_STACK_END_CHECK
797 bool "Detect stack corruption on calls to schedule()"
798 depends on DEBUG_KERNEL
801 This option checks for a stack overrun on calls to schedule().
802 If the stack end location is found to be over written always panic as
803 the content of the corrupted region can no longer be trusted.
804 This is to ensure no erroneous behaviour occurs which could result in
805 data corruption or a sporadic crash at a later stage once the region
806 is examined. The runtime overhead introduced is minimal.
808 config ARCH_HAS_DEBUG_VM_PGTABLE
811 An architecture should select this when it can successfully
812 build and run DEBUG_VM_PGTABLE.
814 config DEBUG_VM_IRQSOFF
815 def_bool DEBUG_VM && !PREEMPT_RT
819 depends on DEBUG_KERNEL
821 Enable this to turn on extended checks in the virtual-memory system
822 that may impact performance.
826 config DEBUG_VM_MAPLE_TREE
827 bool "Debug VM maple trees"
829 select DEBUG_MAPLE_TREE
831 Enable VM maple tree debugging information and extra validations.
836 bool "Debug VM red-black trees"
839 Enable VM red-black tree debugging information and extra validations.
843 config DEBUG_VM_PGFLAGS
844 bool "Debug page-flags operations"
847 Enables extra validation on page flags operations.
851 config DEBUG_VM_PGTABLE
852 bool "Debug arch page table for semantics compliance"
854 depends on ARCH_HAS_DEBUG_VM_PGTABLE
855 default y if DEBUG_VM
857 This option provides a debug method which can be used to test
858 architecture page table helper functions on various platforms in
859 verifying if they comply with expected generic MM semantics. This
860 will help architecture code in making sure that any changes or
861 new additions of these helpers still conform to expected
862 semantics of the generic MM. Platforms will have to opt in for
863 this through ARCH_HAS_DEBUG_VM_PGTABLE.
867 config ARCH_HAS_DEBUG_VIRTUAL
871 bool "Debug VM translations"
872 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
874 Enable some costly sanity checks in virtual to page code. This can
875 catch mistakes with virt_to_page() and friends.
879 config DEBUG_NOMMU_REGIONS
880 bool "Debug the global anon/private NOMMU mapping region tree"
881 depends on DEBUG_KERNEL && !MMU
883 This option causes the global tree of anonymous and private mapping
884 regions to be regularly checked for invalid topology.
886 config DEBUG_MEMORY_INIT
887 bool "Debug memory initialisation" if EXPERT
890 Enable this for additional checks during memory initialisation.
891 The sanity checks verify aspects of the VM such as the memory model
892 and other information provided by the architecture. Verbose
893 information will be printed at KERN_DEBUG loglevel depending
894 on the mminit_loglevel= command-line option.
898 config MEMORY_NOTIFIER_ERROR_INJECT
899 tristate "Memory hotplug notifier error injection module"
900 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
902 This option provides the ability to inject artificial errors to
903 memory hotplug notifier chain callbacks. It is controlled through
904 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
906 If the notifier call chain should be failed with some events
907 notified, write the error code to "actions/<notifier event>/error".
909 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
911 # cd /sys/kernel/debug/notifier-error-inject/memory
912 # echo -12 > actions/MEM_GOING_OFFLINE/error
913 # echo offline > /sys/devices/system/memory/memoryXXX/state
914 bash: echo: write error: Cannot allocate memory
916 To compile this code as a module, choose M here: the module will
917 be called memory-notifier-error-inject.
921 config DEBUG_PER_CPU_MAPS
922 bool "Debug access to per_cpu maps"
923 depends on DEBUG_KERNEL
926 Say Y to verify that the per_cpu map being accessed has
927 been set up. This adds a fair amount of code to kernel memory
928 and decreases performance.
932 config DEBUG_KMAP_LOCAL
933 bool "Debug kmap_local temporary mappings"
934 depends on DEBUG_KERNEL && KMAP_LOCAL
936 This option enables additional error checking for the kmap_local
937 infrastructure. Disable for production use.
939 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
942 config DEBUG_KMAP_LOCAL_FORCE_MAP
943 bool "Enforce kmap_local temporary mappings"
944 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
946 select DEBUG_KMAP_LOCAL
948 This option enforces temporary mappings through the kmap_local
949 mechanism for non-highmem pages and on non-highmem systems.
950 Disable this for production systems!
953 bool "Highmem debugging"
954 depends on DEBUG_KERNEL && HIGHMEM
955 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
956 select DEBUG_KMAP_LOCAL
958 This option enables additional error checking for high memory
959 systems. Disable for production systems.
961 config HAVE_DEBUG_STACKOVERFLOW
964 config DEBUG_STACKOVERFLOW
965 bool "Check for stack overflows"
966 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
968 Say Y here if you want to check for overflows of kernel, IRQ
969 and exception stacks (if your architecture uses them). This
970 option will show detailed messages if free stack space drops
971 below a certain limit.
973 These kinds of bugs usually occur when call-chains in the
974 kernel get too deep, especially when interrupts are
977 Use this in cases where you see apparently random memory
978 corruption, especially if it appears in 'struct thread_info'
980 If in doubt, say "N".
982 source "lib/Kconfig.kasan"
983 source "lib/Kconfig.kfence"
984 source "lib/Kconfig.kmsan"
986 endmenu # "Memory Debugging"
989 bool "Debug shared IRQ handlers"
990 depends on DEBUG_KERNEL
992 Enable this to generate a spurious interrupt just before a shared
993 interrupt handler is deregistered (generating one when registering
994 is currently disabled). Drivers need to handle this correctly. Some
995 don't and need to be caught.
997 menu "Debug Oops, Lockups and Hangs"
1000 bool "Panic on Oops"
1002 Say Y here to enable the kernel to panic when it oopses. This
1003 has the same effect as setting oops=panic on the kernel command
1006 This feature is useful to ensure that the kernel does not do
1007 anything erroneous after an oops which could result in data
1008 corruption or other issues.
1012 config PANIC_ON_OOPS_VALUE
1015 default 0 if !PANIC_ON_OOPS
1016 default 1 if PANIC_ON_OOPS
1018 config PANIC_TIMEOUT
1022 Set the timeout value (in seconds) until a reboot occurs when
1023 the kernel panics. If n = 0, then we wait forever. A timeout
1024 value n > 0 will wait n seconds before rebooting, while a timeout
1025 value n < 0 will reboot immediately.
1027 config LOCKUP_DETECTOR
1030 config SOFTLOCKUP_DETECTOR
1031 bool "Detect Soft Lockups"
1032 depends on DEBUG_KERNEL && !S390
1033 select LOCKUP_DETECTOR
1035 Say Y here to enable the kernel to act as a watchdog to detect
1038 Softlockups are bugs that cause the kernel to loop in kernel
1039 mode for more than 20 seconds, without giving other tasks a
1040 chance to run. The current stack trace is displayed upon
1041 detection and the system will stay locked up.
1043 config BOOTPARAM_SOFTLOCKUP_PANIC
1044 bool "Panic (Reboot) On Soft Lockups"
1045 depends on SOFTLOCKUP_DETECTOR
1047 Say Y here to enable the kernel to panic on "soft lockups",
1048 which are bugs that cause the kernel to loop in kernel
1049 mode for more than 20 seconds (configurable using the watchdog_thresh
1050 sysctl), without giving other tasks a chance to run.
1052 The panic can be used in combination with panic_timeout,
1053 to cause the system to reboot automatically after a
1054 lockup has been detected. This feature is useful for
1055 high-availability systems that have uptime guarantees and
1056 where a lockup must be resolved ASAP.
1060 config HARDLOCKUP_DETECTOR_PERF
1062 select SOFTLOCKUP_DETECTOR
1065 # Enables a timestamp based low pass filter to compensate for perf based
1066 # hard lockup detection which runs too fast due to turbo modes.
1068 config HARDLOCKUP_CHECK_TIMESTAMP
1072 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1073 # lockup detector rather than the perf based detector.
1075 config HARDLOCKUP_DETECTOR
1076 bool "Detect Hard Lockups"
1077 depends on DEBUG_KERNEL && !S390
1078 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1079 select LOCKUP_DETECTOR
1080 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1082 Say Y here to enable the kernel to act as a watchdog to detect
1085 Hardlockups are bugs that cause the CPU to loop in kernel mode
1086 for more than 10 seconds, without letting other interrupts have a
1087 chance to run. The current stack trace is displayed upon detection
1088 and the system will stay locked up.
1090 config BOOTPARAM_HARDLOCKUP_PANIC
1091 bool "Panic (Reboot) On Hard Lockups"
1092 depends on HARDLOCKUP_DETECTOR
1094 Say Y here to enable the kernel to panic on "hard lockups",
1095 which are bugs that cause the kernel to loop in kernel
1096 mode with interrupts disabled for more than 10 seconds (configurable
1097 using the watchdog_thresh sysctl).
1101 config DETECT_HUNG_TASK
1102 bool "Detect Hung Tasks"
1103 depends on DEBUG_KERNEL
1104 default SOFTLOCKUP_DETECTOR
1106 Say Y here to enable the kernel to detect "hung tasks",
1107 which are bugs that cause the task to be stuck in
1108 uninterruptible "D" state indefinitely.
1110 When a hung task is detected, the kernel will print the
1111 current stack trace (which you should report), but the
1112 task will stay in uninterruptible state. If lockdep is
1113 enabled then all held locks will also be reported. This
1114 feature has negligible overhead.
1116 config DEFAULT_HUNG_TASK_TIMEOUT
1117 int "Default timeout for hung task detection (in seconds)"
1118 depends on DETECT_HUNG_TASK
1121 This option controls the default timeout (in seconds) used
1122 to determine when a task has become non-responsive and should
1125 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1126 sysctl or by writing a value to
1127 /proc/sys/kernel/hung_task_timeout_secs.
1129 A timeout of 0 disables the check. The default is two minutes.
1130 Keeping the default should be fine in most cases.
1132 config BOOTPARAM_HUNG_TASK_PANIC
1133 bool "Panic (Reboot) On Hung Tasks"
1134 depends on DETECT_HUNG_TASK
1136 Say Y here to enable the kernel to panic on "hung tasks",
1137 which are bugs that cause the kernel to leave a task stuck
1138 in uninterruptible "D" state.
1140 The panic can be used in combination with panic_timeout,
1141 to cause the system to reboot automatically after a
1142 hung task has been detected. This feature is useful for
1143 high-availability systems that have uptime guarantees and
1144 where a hung tasks must be resolved ASAP.
1149 bool "Detect Workqueue Stalls"
1150 depends on DEBUG_KERNEL
1152 Say Y here to enable stall detection on workqueues. If a
1153 worker pool doesn't make forward progress on a pending work
1154 item for over a given amount of time, 30s by default, a
1155 warning message is printed along with dump of workqueue
1156 state. This can be configured through kernel parameter
1157 "workqueue.watchdog_thresh" and its sysfs counterpart.
1160 tristate "Test module to generate lockups"
1163 This builds the "test_lockup" module that helps to make sure
1164 that watchdogs and lockup detectors are working properly.
1166 Depending on module parameters it could emulate soft or hard
1167 lockup, "hung task", or locking arbitrary lock for a long time.
1168 Also it could generate series of lockups with cooling-down periods.
1172 endmenu # "Debug lockups and hangs"
1174 menu "Scheduler Debugging"
1177 bool "Collect scheduler debugging info"
1178 depends on DEBUG_KERNEL && PROC_FS
1181 If you say Y here, the /proc/sched_debug file will be provided
1182 that can help debug the scheduler. The runtime overhead of this
1190 bool "Collect scheduler statistics"
1191 depends on DEBUG_KERNEL && PROC_FS
1194 If you say Y here, additional code will be inserted into the
1195 scheduler and related routines to collect statistics about
1196 scheduler behavior and provide them in /proc/schedstat. These
1197 stats may be useful for both tuning and debugging the scheduler
1198 If you aren't debugging the scheduler or trying to tune a specific
1199 application, you can say N to avoid the very slight overhead
1204 config DEBUG_TIMEKEEPING
1205 bool "Enable extra timekeeping sanity checking"
1207 This option will enable additional timekeeping sanity checks
1208 which may be helpful when diagnosing issues where timekeeping
1209 problems are suspected.
1211 This may include checks in the timekeeping hotpaths, so this
1212 option may have a (very small) performance impact to some
1217 config DEBUG_PREEMPT
1218 bool "Debug preemptible kernel"
1219 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1222 If you say Y here then the kernel will use a debug variant of the
1223 commonly used smp_processor_id() function and will print warnings
1224 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1225 will detect preemption count underflows.
1227 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1229 config LOCK_DEBUGGING_SUPPORT
1231 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1234 config PROVE_LOCKING
1235 bool "Lock debugging: prove locking correctness"
1236 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1238 select DEBUG_SPINLOCK
1239 select DEBUG_MUTEXES if !PREEMPT_RT
1240 select DEBUG_RT_MUTEXES if RT_MUTEXES
1242 select DEBUG_WW_MUTEX_SLOWPATH
1243 select DEBUG_LOCK_ALLOC
1244 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1245 select TRACE_IRQFLAGS
1248 This feature enables the kernel to prove that all locking
1249 that occurs in the kernel runtime is mathematically
1250 correct: that under no circumstance could an arbitrary (and
1251 not yet triggered) combination of observed locking
1252 sequences (on an arbitrary number of CPUs, running an
1253 arbitrary number of tasks and interrupt contexts) cause a
1256 In short, this feature enables the kernel to report locking
1257 related deadlocks before they actually occur.
1259 The proof does not depend on how hard and complex a
1260 deadlock scenario would be to trigger: how many
1261 participant CPUs, tasks and irq-contexts would be needed
1262 for it to trigger. The proof also does not depend on
1263 timing: if a race and a resulting deadlock is possible
1264 theoretically (no matter how unlikely the race scenario
1265 is), it will be proven so and will immediately be
1266 reported by the kernel (once the event is observed that
1267 makes the deadlock theoretically possible).
1269 If a deadlock is impossible (i.e. the locking rules, as
1270 observed by the kernel, are mathematically correct), the
1271 kernel reports nothing.
1273 NOTE: this feature can also be enabled for rwlocks, mutexes
1274 and rwsems - in which case all dependencies between these
1275 different locking variants are observed and mapped too, and
1276 the proof of observed correctness is also maintained for an
1277 arbitrary combination of these separate locking variants.
1279 For more details, see Documentation/locking/lockdep-design.rst.
1281 config PROVE_RAW_LOCK_NESTING
1282 bool "Enable raw_spinlock - spinlock nesting checks"
1283 depends on PROVE_LOCKING
1286 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1287 that the lock nesting rules for PREEMPT_RT enabled kernels are
1290 NOTE: There are known nesting problems. So if you enable this
1291 option expect lockdep splats until these problems have been fully
1292 addressed which is work in progress. This config switch allows to
1293 identify and analyze these problems. It will be removed and the
1294 check permanently enabled once the main issues have been fixed.
1296 If unsure, select N.
1299 bool "Lock usage statistics"
1300 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1302 select DEBUG_SPINLOCK
1303 select DEBUG_MUTEXES if !PREEMPT_RT
1304 select DEBUG_RT_MUTEXES if RT_MUTEXES
1305 select DEBUG_LOCK_ALLOC
1308 This feature enables tracking lock contention points
1310 For more details, see Documentation/locking/lockstat.rst
1312 This also enables lock events required by "perf lock",
1314 If you want to use "perf lock", you also need to turn on
1315 CONFIG_EVENT_TRACING.
1317 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1318 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1320 config DEBUG_RT_MUTEXES
1321 bool "RT Mutex debugging, deadlock detection"
1322 depends on DEBUG_KERNEL && RT_MUTEXES
1324 This allows rt mutex semantics violations and rt mutex related
1325 deadlocks (lockups) to be detected and reported automatically.
1327 config DEBUG_SPINLOCK
1328 bool "Spinlock and rw-lock debugging: basic checks"
1329 depends on DEBUG_KERNEL
1330 select UNINLINE_SPIN_UNLOCK
1332 Say Y here and build SMP to catch missing spinlock initialization
1333 and certain other kinds of spinlock errors commonly made. This is
1334 best used in conjunction with the NMI watchdog so that spinlock
1335 deadlocks are also debuggable.
1337 config DEBUG_MUTEXES
1338 bool "Mutex debugging: basic checks"
1339 depends on DEBUG_KERNEL && !PREEMPT_RT
1341 This feature allows mutex semantics violations to be detected and
1344 config DEBUG_WW_MUTEX_SLOWPATH
1345 bool "Wait/wound mutex debugging: Slowpath testing"
1346 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1347 select DEBUG_LOCK_ALLOC
1348 select DEBUG_SPINLOCK
1349 select DEBUG_MUTEXES if !PREEMPT_RT
1350 select DEBUG_RT_MUTEXES if PREEMPT_RT
1352 This feature enables slowpath testing for w/w mutex users by
1353 injecting additional -EDEADLK wound/backoff cases. Together with
1354 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1355 will test all possible w/w mutex interface abuse with the
1356 exception of simply not acquiring all the required locks.
1357 Note that this feature can introduce significant overhead, so
1358 it really should not be enabled in a production or distro kernel,
1359 even a debug kernel. If you are a driver writer, enable it. If
1360 you are a distro, do not.
1363 bool "RW Semaphore debugging: basic checks"
1364 depends on DEBUG_KERNEL
1366 This debugging feature allows mismatched rw semaphore locks
1367 and unlocks to be detected and reported.
1369 config DEBUG_LOCK_ALLOC
1370 bool "Lock debugging: detect incorrect freeing of live locks"
1371 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1372 select DEBUG_SPINLOCK
1373 select DEBUG_MUTEXES if !PREEMPT_RT
1374 select DEBUG_RT_MUTEXES if RT_MUTEXES
1377 This feature will check whether any held lock (spinlock, rwlock,
1378 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1379 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1380 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1381 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1382 held during task exit.
1386 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1391 config LOCKDEP_SMALL
1395 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1396 depends on LOCKDEP && !LOCKDEP_SMALL
1400 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1402 config LOCKDEP_CHAINS_BITS
1403 int "Bitsize for MAX_LOCKDEP_CHAINS"
1404 depends on LOCKDEP && !LOCKDEP_SMALL
1408 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1410 config LOCKDEP_STACK_TRACE_BITS
1411 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1412 depends on LOCKDEP && !LOCKDEP_SMALL
1416 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1418 config LOCKDEP_STACK_TRACE_HASH_BITS
1419 int "Bitsize for STACK_TRACE_HASH_SIZE"
1420 depends on LOCKDEP && !LOCKDEP_SMALL
1424 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1426 config LOCKDEP_CIRCULAR_QUEUE_BITS
1427 int "Bitsize for elements in circular_queue struct"
1432 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1434 config DEBUG_LOCKDEP
1435 bool "Lock dependency engine debugging"
1436 depends on DEBUG_KERNEL && LOCKDEP
1437 select DEBUG_IRQFLAGS
1439 If you say Y here, the lock dependency engine will do
1440 additional runtime checks to debug itself, at the price
1441 of more runtime overhead.
1443 config DEBUG_ATOMIC_SLEEP
1444 bool "Sleep inside atomic section checking"
1445 select PREEMPT_COUNT
1446 depends on DEBUG_KERNEL
1447 depends on !ARCH_NO_PREEMPT
1449 If you say Y here, various routines which may sleep will become very
1450 noisy if they are called inside atomic sections: when a spinlock is
1451 held, inside an rcu read side critical section, inside preempt disabled
1452 sections, inside an interrupt, etc...
1454 config DEBUG_LOCKING_API_SELFTESTS
1455 bool "Locking API boot-time self-tests"
1456 depends on DEBUG_KERNEL
1458 Say Y here if you want the kernel to run a short self-test during
1459 bootup. The self-test checks whether common types of locking bugs
1460 are detected by debugging mechanisms or not. (if you disable
1461 lock debugging then those bugs won't be detected of course.)
1462 The following locking APIs are covered: spinlocks, rwlocks,
1465 config LOCK_TORTURE_TEST
1466 tristate "torture tests for locking"
1467 depends on DEBUG_KERNEL
1470 This option provides a kernel module that runs torture tests
1471 on kernel locking primitives. The kernel module may be built
1472 after the fact on the running kernel to be tested, if desired.
1474 Say Y here if you want kernel locking-primitive torture tests
1475 to be built into the kernel.
1476 Say M if you want these torture tests to build as a module.
1477 Say N if you are unsure.
1479 config WW_MUTEX_SELFTEST
1480 tristate "Wait/wound mutex selftests"
1482 This option provides a kernel module that runs tests on the
1483 on the struct ww_mutex locking API.
1485 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1486 with this test harness.
1488 Say M if you want these self tests to build as a module.
1489 Say N if you are unsure.
1491 config SCF_TORTURE_TEST
1492 tristate "torture tests for smp_call_function*()"
1493 depends on DEBUG_KERNEL
1496 This option provides a kernel module that runs torture tests
1497 on the smp_call_function() family of primitives. The kernel
1498 module may be built after the fact on the running kernel to
1499 be tested, if desired.
1501 config CSD_LOCK_WAIT_DEBUG
1502 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1503 depends on DEBUG_KERNEL
1507 This option enables debug prints when CPUs are slow to respond
1508 to the smp_call_function*() IPI wrappers. These debug prints
1509 include the IPI handler function currently executing (if any)
1510 and relevant stack traces.
1512 endmenu # lock debugging
1514 config TRACE_IRQFLAGS
1515 depends on TRACE_IRQFLAGS_SUPPORT
1518 Enables hooks to interrupt enabling and disabling for
1519 either tracing or lock debugging.
1521 config TRACE_IRQFLAGS_NMI
1523 depends on TRACE_IRQFLAGS
1524 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1526 config DEBUG_IRQFLAGS
1527 bool "Debug IRQ flag manipulation"
1529 Enables checks for potentially unsafe enabling or disabling of
1530 interrupts, such as calling raw_local_irq_restore() when interrupts
1534 bool "Stack backtrace support"
1535 depends on STACKTRACE_SUPPORT
1537 This option causes the kernel to create a /proc/pid/stack for
1538 every process, showing its current stack trace.
1539 It is also used by various kernel debugging features that require
1540 stack trace generation.
1542 config WARN_ALL_UNSEEDED_RANDOM
1543 bool "Warn for all uses of unseeded randomness"
1546 Some parts of the kernel contain bugs relating to their use of
1547 cryptographically secure random numbers before it's actually possible
1548 to generate those numbers securely. This setting ensures that these
1549 flaws don't go unnoticed, by enabling a message, should this ever
1550 occur. This will allow people with obscure setups to know when things
1551 are going wrong, so that they might contact developers about fixing
1554 Unfortunately, on some models of some architectures getting
1555 a fully seeded CRNG is extremely difficult, and so this can
1556 result in dmesg getting spammed for a surprisingly long
1557 time. This is really bad from a security perspective, and
1558 so architecture maintainers really need to do what they can
1559 to get the CRNG seeded sooner after the system is booted.
1560 However, since users cannot do anything actionable to
1561 address this, by default this option is disabled.
1563 Say Y here if you want to receive warnings for all uses of
1564 unseeded randomness. This will be of use primarily for
1565 those developers interested in improving the security of
1566 Linux kernels running on their architecture (or
1569 config DEBUG_KOBJECT
1570 bool "kobject debugging"
1571 depends on DEBUG_KERNEL
1573 If you say Y here, some extra kobject debugging messages will be sent
1576 config DEBUG_KOBJECT_RELEASE
1577 bool "kobject release debugging"
1578 depends on DEBUG_OBJECTS_TIMERS
1580 kobjects are reference counted objects. This means that their
1581 last reference count put is not predictable, and the kobject can
1582 live on past the point at which a driver decides to drop its
1583 initial reference to the kobject gained on allocation. An
1584 example of this would be a struct device which has just been
1587 However, some buggy drivers assume that after such an operation,
1588 the memory backing the kobject can be immediately freed. This
1589 goes completely against the principles of a refcounted object.
1591 If you say Y here, the kernel will delay the release of kobjects
1592 on the last reference count to improve the visibility of this
1593 kind of kobject release bug.
1595 config HAVE_DEBUG_BUGVERBOSE
1598 menu "Debug kernel data structures"
1601 bool "Debug linked list manipulation"
1602 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1604 Enable this to turn on extended checks in the linked-list
1610 bool "Debug priority linked list manipulation"
1611 depends on DEBUG_KERNEL
1613 Enable this to turn on extended checks in the priority-ordered
1614 linked-list (plist) walking routines. This checks the entire
1615 list multiple times during each manipulation.
1620 bool "Debug SG table operations"
1621 depends on DEBUG_KERNEL
1623 Enable this to turn on checks on scatter-gather tables. This can
1624 help find problems with drivers that do not properly initialize
1629 config DEBUG_NOTIFIERS
1630 bool "Debug notifier call chains"
1631 depends on DEBUG_KERNEL
1633 Enable this to turn on sanity checking for notifier call chains.
1634 This is most useful for kernel developers to make sure that
1635 modules properly unregister themselves from notifier chains.
1636 This is a relatively cheap check but if you care about maximum
1639 config BUG_ON_DATA_CORRUPTION
1640 bool "Trigger a BUG when data corruption is detected"
1643 Select this option if the kernel should BUG when it encounters
1644 data corruption in kernel memory structures when they get checked
1649 config DEBUG_MAPLE_TREE
1650 bool "Debug maple trees"
1651 depends on DEBUG_KERNEL
1653 Enable maple tree debugging information and extra validations.
1659 config DEBUG_CREDENTIALS
1660 bool "Debug credential management"
1661 depends on DEBUG_KERNEL
1663 Enable this to turn on some debug checking for credential
1664 management. The additional code keeps track of the number of
1665 pointers from task_structs to any given cred struct, and checks to
1666 see that this number never exceeds the usage count of the cred
1669 Furthermore, if SELinux is enabled, this also checks that the
1670 security pointer in the cred struct is never seen to be invalid.
1674 source "kernel/rcu/Kconfig.debug"
1676 config DEBUG_WQ_FORCE_RR_CPU
1677 bool "Force round-robin CPU selection for unbound work items"
1678 depends on DEBUG_KERNEL
1681 Workqueue used to implicitly guarantee that work items queued
1682 without explicit CPU specified are put on the local CPU. This
1683 guarantee is no longer true and while local CPU is still
1684 preferred work items may be put on foreign CPUs. Kernel
1685 parameter "workqueue.debug_force_rr_cpu" is added to force
1686 round-robin CPU selection to flush out usages which depend on the
1687 now broken guarantee. This config option enables the debug
1688 feature by default. When enabled, memory and cache locality will
1691 config CPU_HOTPLUG_STATE_CONTROL
1692 bool "Enable CPU hotplug state control"
1693 depends on DEBUG_KERNEL
1694 depends on HOTPLUG_CPU
1697 Allows to write steps between "offline" and "online" to the CPUs
1698 sysfs target file so states can be stepped granular. This is a debug
1699 option for now as the hotplug machinery cannot be stopped and
1700 restarted at arbitrary points yet.
1702 Say N if your are unsure.
1705 bool "Latency measuring infrastructure"
1706 depends on DEBUG_KERNEL
1707 depends on STACKTRACE_SUPPORT
1709 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1715 Enable this option if you want to use the LatencyTOP tool
1716 to find out which userspace is blocking on what kernel operations.
1718 source "kernel/trace/Kconfig"
1720 config PROVIDE_OHCI1394_DMA_INIT
1721 bool "Remote debugging over FireWire early on boot"
1722 depends on PCI && X86
1724 If you want to debug problems which hang or crash the kernel early
1725 on boot and the crashing machine has a FireWire port, you can use
1726 this feature to remotely access the memory of the crashed machine
1727 over FireWire. This employs remote DMA as part of the OHCI1394
1728 specification which is now the standard for FireWire controllers.
1730 With remote DMA, you can monitor the printk buffer remotely using
1731 firescope and access all memory below 4GB using fireproxy from gdb.
1732 Even controlling a kernel debugger is possible using remote DMA.
1736 If ohci1394_dma=early is used as boot parameter, it will initialize
1737 all OHCI1394 controllers which are found in the PCI config space.
1739 As all changes to the FireWire bus such as enabling and disabling
1740 devices cause a bus reset and thereby disable remote DMA for all
1741 devices, be sure to have the cable plugged and FireWire enabled on
1742 the debugging host before booting the debug target for debugging.
1744 This code (~1k) is freed after boot. By then, the firewire stack
1745 in charge of the OHCI-1394 controllers should be used instead.
1747 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1749 source "samples/Kconfig"
1751 config ARCH_HAS_DEVMEM_IS_ALLOWED
1754 config STRICT_DEVMEM
1755 bool "Filter access to /dev/mem"
1756 depends on MMU && DEVMEM
1757 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1758 default y if PPC || X86 || ARM64
1760 If this option is disabled, you allow userspace (root) access to all
1761 of memory, including kernel and userspace memory. Accidental
1762 access to this is obviously disastrous, but specific access can
1763 be used by people debugging the kernel. Note that with PAT support
1764 enabled, even in this case there are restrictions on /dev/mem
1765 use due to the cache aliasing requirements.
1767 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1768 file only allows userspace access to PCI space and the BIOS code and
1769 data regions. This is sufficient for dosemu and X and all common
1774 config IO_STRICT_DEVMEM
1775 bool "Filter I/O access to /dev/mem"
1776 depends on STRICT_DEVMEM
1778 If this option is disabled, you allow userspace (root) access to all
1779 io-memory regardless of whether a driver is actively using that
1780 range. Accidental access to this is obviously disastrous, but
1781 specific access can be used by people debugging kernel drivers.
1783 If this option is switched on, the /dev/mem file only allows
1784 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1785 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1786 if the driver using a given range cannot be disabled.
1790 menu "$(SRCARCH) Debugging"
1792 source "arch/$(SRCARCH)/Kconfig.debug"
1796 menu "Kernel Testing and Coverage"
1798 source "lib/kunit/Kconfig"
1800 config NOTIFIER_ERROR_INJECTION
1801 tristate "Notifier error injection"
1802 depends on DEBUG_KERNEL
1805 This option provides the ability to inject artificial errors to
1806 specified notifier chain callbacks. It is useful to test the error
1807 handling of notifier call chain failures.
1811 config PM_NOTIFIER_ERROR_INJECT
1812 tristate "PM notifier error injection module"
1813 depends on PM && NOTIFIER_ERROR_INJECTION
1814 default m if PM_DEBUG
1816 This option provides the ability to inject artificial errors to
1817 PM notifier chain callbacks. It is controlled through debugfs
1818 interface /sys/kernel/debug/notifier-error-inject/pm
1820 If the notifier call chain should be failed with some events
1821 notified, write the error code to "actions/<notifier event>/error".
1823 Example: Inject PM suspend error (-12 = -ENOMEM)
1825 # cd /sys/kernel/debug/notifier-error-inject/pm/
1826 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1827 # echo mem > /sys/power/state
1828 bash: echo: write error: Cannot allocate memory
1830 To compile this code as a module, choose M here: the module will
1831 be called pm-notifier-error-inject.
1835 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1836 tristate "OF reconfig notifier error injection module"
1837 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1839 This option provides the ability to inject artificial errors to
1840 OF reconfig notifier chain callbacks. It is controlled
1841 through debugfs interface under
1842 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1844 If the notifier call chain should be failed with some events
1845 notified, write the error code to "actions/<notifier event>/error".
1847 To compile this code as a module, choose M here: the module will
1848 be called of-reconfig-notifier-error-inject.
1852 config NETDEV_NOTIFIER_ERROR_INJECT
1853 tristate "Netdev notifier error injection module"
1854 depends on NET && NOTIFIER_ERROR_INJECTION
1856 This option provides the ability to inject artificial errors to
1857 netdevice notifier chain callbacks. It is controlled through debugfs
1858 interface /sys/kernel/debug/notifier-error-inject/netdev
1860 If the notifier call chain should be failed with some events
1861 notified, write the error code to "actions/<notifier event>/error".
1863 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1865 # cd /sys/kernel/debug/notifier-error-inject/netdev
1866 # echo -22 > actions/NETDEV_CHANGEMTU/error
1867 # ip link set eth0 mtu 1024
1868 RTNETLINK answers: Invalid argument
1870 To compile this code as a module, choose M here: the module will
1871 be called netdev-notifier-error-inject.
1875 config FUNCTION_ERROR_INJECTION
1877 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1879 config FAULT_INJECTION
1880 bool "Fault-injection framework"
1881 depends on DEBUG_KERNEL
1883 Provide fault-injection framework.
1884 For more details, see Documentation/fault-injection/.
1887 bool "Fault-injection capability for kmalloc"
1888 depends on FAULT_INJECTION
1889 depends on SLAB || SLUB
1891 Provide fault-injection capability for kmalloc.
1893 config FAIL_PAGE_ALLOC
1894 bool "Fault-injection capability for alloc_pages()"
1895 depends on FAULT_INJECTION
1897 Provide fault-injection capability for alloc_pages().
1899 config FAULT_INJECTION_USERCOPY
1900 bool "Fault injection capability for usercopy functions"
1901 depends on FAULT_INJECTION
1903 Provides fault-injection capability to inject failures
1904 in usercopy functions (copy_from_user(), get_user(), ...).
1906 config FAIL_MAKE_REQUEST
1907 bool "Fault-injection capability for disk IO"
1908 depends on FAULT_INJECTION && BLOCK
1910 Provide fault-injection capability for disk IO.
1912 config FAIL_IO_TIMEOUT
1913 bool "Fault-injection capability for faking disk interrupts"
1914 depends on FAULT_INJECTION && BLOCK
1916 Provide fault-injection capability on end IO handling. This
1917 will make the block layer "forget" an interrupt as configured,
1918 thus exercising the error handling.
1920 Only works with drivers that use the generic timeout handling,
1921 for others it won't do anything.
1924 bool "Fault-injection capability for futexes"
1926 depends on FAULT_INJECTION && FUTEX
1928 Provide fault-injection capability for futexes.
1930 config FAULT_INJECTION_DEBUG_FS
1931 bool "Debugfs entries for fault-injection capabilities"
1932 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1934 Enable configuration of fault-injection capabilities via debugfs.
1936 config FAIL_FUNCTION
1937 bool "Fault-injection capability for functions"
1938 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1940 Provide function-based fault-injection capability.
1941 This will allow you to override a specific function with a return
1942 with given return value. As a result, function caller will see
1943 an error value and have to handle it. This is useful to test the
1944 error handling in various subsystems.
1946 config FAIL_MMC_REQUEST
1947 bool "Fault-injection capability for MMC IO"
1948 depends on FAULT_INJECTION_DEBUG_FS && MMC
1950 Provide fault-injection capability for MMC IO.
1951 This will make the mmc core return data errors. This is
1952 useful to test the error handling in the mmc block device
1953 and to test how the mmc host driver handles retries from
1957 bool "Fault-injection capability for SunRPC"
1958 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1960 Provide fault-injection capability for SunRPC and
1963 config FAULT_INJECTION_STACKTRACE_FILTER
1964 bool "stacktrace filter for fault-injection capabilities"
1965 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1968 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1970 Provide stacktrace filter for fault-injection capabilities
1972 config ARCH_HAS_KCOV
1975 An architecture should select this when it can successfully
1976 build and run with CONFIG_KCOV. This typically requires
1977 disabling instrumentation for some early boot code.
1979 config CC_HAS_SANCOV_TRACE_PC
1980 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1984 bool "Code coverage for fuzzing"
1985 depends on ARCH_HAS_KCOV
1986 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1987 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
1988 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
1990 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1991 select OBJTOOL if HAVE_NOINSTR_HACK
1993 KCOV exposes kernel code coverage information in a form suitable
1994 for coverage-guided fuzzing (randomized testing).
1996 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1997 different machines and across reboots. If you need stable PC values,
1998 disable RANDOMIZE_BASE.
2000 For more details, see Documentation/dev-tools/kcov.rst.
2002 config KCOV_ENABLE_COMPARISONS
2003 bool "Enable comparison operands collection by KCOV"
2005 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2007 KCOV also exposes operands of every comparison in the instrumented
2008 code along with operand sizes and PCs of the comparison instructions.
2009 These operands can be used by fuzzing engines to improve the quality
2010 of fuzzing coverage.
2012 config KCOV_INSTRUMENT_ALL
2013 bool "Instrument all code by default"
2017 If you are doing generic system call fuzzing (like e.g. syzkaller),
2018 then you will want to instrument the whole kernel and you should
2019 say y here. If you are doing more targeted fuzzing (like e.g.
2020 filesystem fuzzing with AFL) then you will want to enable coverage
2021 for more specific subsets of files, and should say n here.
2023 config KCOV_IRQ_AREA_SIZE
2024 hex "Size of interrupt coverage collection area in words"
2028 KCOV uses preallocated per-cpu areas to collect coverage from
2029 soft interrupts. This specifies the size of those areas in the
2030 number of unsigned long words.
2032 menuconfig RUNTIME_TESTING_MENU
2033 bool "Runtime Testing"
2036 if RUNTIME_TESTING_MENU
2039 tristate "Linux Kernel Dump Test Tool Module"
2042 This module enables testing of the different dumping mechanisms by
2043 inducing system failures at predefined crash points.
2044 If you don't need it: say N
2045 Choose M here to compile this code as a module. The module will be
2048 Documentation on how to use the module can be found in
2049 Documentation/fault-injection/provoke-crashes.rst
2051 config CPUMASK_KUNIT_TEST
2052 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2054 default KUNIT_ALL_TESTS
2056 Enable to turn on cpumask tests, running at boot or module load time.
2058 For more information on KUnit and unit tests in general, please refer
2059 to the KUnit documentation in Documentation/dev-tools/kunit/.
2063 config TEST_LIST_SORT
2064 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2066 default KUNIT_ALL_TESTS
2068 Enable this to turn on 'list_sort()' function test. This test is
2069 executed only once during system boot (so affects only boot time),
2070 or at module load time.
2074 config TEST_MIN_HEAP
2075 tristate "Min heap test"
2076 depends on DEBUG_KERNEL || m
2078 Enable this to turn on min heap function tests. This test is
2079 executed only once during system boot (so affects only boot time),
2080 or at module load time.
2085 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2087 default KUNIT_ALL_TESTS
2089 This option enables the self-test function of 'sort()' at boot,
2090 or at module load time.
2095 tristate "64bit/32bit division and modulo test"
2096 depends on DEBUG_KERNEL || m
2098 Enable this to turn on 'do_div()' function test. This test is
2099 executed only once during system boot (so affects only boot time),
2100 or at module load time.
2104 config KPROBES_SANITY_TEST
2105 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2106 depends on DEBUG_KERNEL
2109 default KUNIT_ALL_TESTS
2111 This option provides for testing basic kprobes functionality on
2112 boot. Samples of kprobe and kretprobe are inserted and
2113 verified for functionality.
2115 Say N if you are unsure.
2117 config FPROBE_SANITY_TEST
2118 bool "Self test for fprobe"
2119 depends on DEBUG_KERNEL
2123 This option will enable testing the fprobe when the system boot.
2124 A series of tests are made to verify that the fprobe is functioning
2127 Say N if you are unsure.
2129 config BACKTRACE_SELF_TEST
2130 tristate "Self test for the backtrace code"
2131 depends on DEBUG_KERNEL
2133 This option provides a kernel module that can be used to test
2134 the kernel stack backtrace code. This option is not useful
2135 for distributions or general kernels, but only for kernel
2136 developers working on architecture code.
2138 Note that if you want to also test saved backtraces, you will
2139 have to enable STACKTRACE as well.
2141 Say N if you are unsure.
2143 config TEST_REF_TRACKER
2144 tristate "Self test for reference tracker"
2145 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2148 This option provides a kernel module performing tests
2149 using reference tracker infrastructure.
2151 Say N if you are unsure.
2154 tristate "Red-Black tree test"
2155 depends on DEBUG_KERNEL
2157 A benchmark measuring the performance of the rbtree library.
2158 Also includes rbtree invariant checks.
2160 config REED_SOLOMON_TEST
2161 tristate "Reed-Solomon library test"
2162 depends on DEBUG_KERNEL || m
2164 select REED_SOLOMON_ENC16
2165 select REED_SOLOMON_DEC16
2167 This option enables the self-test function of rslib at boot,
2168 or at module load time.
2172 config INTERVAL_TREE_TEST
2173 tristate "Interval tree test"
2174 depends on DEBUG_KERNEL
2175 select INTERVAL_TREE
2177 A benchmark measuring the performance of the interval tree library
2180 tristate "Per cpu operations test"
2181 depends on m && DEBUG_KERNEL
2183 Enable this option to build test module which validates per-cpu
2188 config ATOMIC64_SELFTEST
2189 tristate "Perform an atomic64_t self-test"
2191 Enable this option to test the atomic64_t functions at boot or
2192 at module load time.
2196 config ASYNC_RAID6_TEST
2197 tristate "Self test for hardware accelerated raid6 recovery"
2198 depends on ASYNC_RAID6_RECOV
2201 This is a one-shot self test that permutes through the
2202 recovery of all the possible two disk failure scenarios for a
2203 N-disk array. Recovery is performed with the asynchronous
2204 raid6 recovery routines, and will optionally use an offload
2205 engine if one is available.
2210 tristate "Test functions located in the hexdump module at runtime"
2212 config STRING_SELFTEST
2213 tristate "Test string functions at runtime"
2215 config TEST_STRING_HELPERS
2216 tristate "Test functions located in the string_helpers module at runtime"
2219 tristate "Test strscpy*() family of functions at runtime"
2222 tristate "Test kstrto*() family of functions at runtime"
2225 tristate "Test printf() family of functions at runtime"
2228 tristate "Test scanf() family of functions at runtime"
2231 tristate "Test bitmap_*() family of functions at runtime"
2233 Enable this option to test the bitmap functions at boot.
2238 tristate "Test functions located in the uuid module at runtime"
2241 tristate "Test the XArray code at runtime"
2243 config TEST_RHASHTABLE
2244 tristate "Perform selftest on resizable hash table"
2246 Enable this option to test the rhashtable functions at boot.
2251 tristate "Perform selftest on siphash functions"
2253 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2254 functions on boot (or module load).
2256 This is intended to help people writing architecture-specific
2257 optimized versions. If unsure, say N.
2260 tristate "Perform selftest on IDA functions"
2263 tristate "Perform selftest on priority array manager"
2266 Enable this option to test priority array manager on boot
2271 config TEST_IRQ_TIMINGS
2272 bool "IRQ timings selftest"
2273 depends on IRQ_TIMINGS
2275 Enable this option to test the irq timings code on boot.
2280 tristate "Test module loading with 'hello world' module"
2283 This builds the "test_module" module that emits "Hello, world"
2284 on printk when loaded. It is designed to be used for basic
2285 evaluation of the module loading subsystem (for example when
2286 validating module verification). It lacks any extra dependencies,
2287 and will not normally be loaded by the system unless explicitly
2293 tristate "Test module for compilation of bitops operations"
2296 This builds the "test_bitops" module that is much like the
2297 TEST_LKM module except that it does a basic exercise of the
2298 set/clear_bit macros and get_count_order/long to make sure there are
2299 no compiler warnings from C=1 sparse checker or -Wextra
2300 compilations. It has no dependencies and doesn't run or load unless
2301 explicitly requested by name. for example: modprobe test_bitops.
2306 tristate "Test module for stress/performance analysis of vmalloc allocator"
2311 This builds the "test_vmalloc" module that should be used for
2312 stress and performance analysis. So, any new change for vmalloc
2313 subsystem can be evaluated from performance and stability point
2318 config TEST_USER_COPY
2319 tristate "Test user/kernel boundary protections"
2322 This builds the "test_user_copy" module that runs sanity checks
2323 on the copy_to/from_user infrastructure, making sure basic
2324 user/kernel boundary testing is working. If it fails to load,
2325 a regression has been detected in the user/kernel memory boundary
2331 tristate "Test BPF filter functionality"
2334 This builds the "test_bpf" module that runs various test vectors
2335 against the BPF interpreter or BPF JIT compiler depending on the
2336 current setting. This is in particular useful for BPF JIT compiler
2337 development, but also to run regression tests against changes in
2338 the interpreter code. It also enables test stubs for eBPF maps and
2339 verifier used by user space verifier testsuite.
2343 config TEST_BLACKHOLE_DEV
2344 tristate "Test blackhole netdev functionality"
2347 This builds the "test_blackhole_dev" module that validates the
2348 data path through this blackhole netdev.
2352 config FIND_BIT_BENCHMARK
2353 tristate "Test find_bit functions"
2355 This builds the "test_find_bit" module that measure find_*_bit()
2356 functions performance.
2360 config TEST_FIRMWARE
2361 tristate "Test firmware loading via userspace interface"
2362 depends on FW_LOADER
2364 This builds the "test_firmware" module that creates a userspace
2365 interface for testing firmware loading. This can be used to
2366 control the triggering of firmware loading without needing an
2367 actual firmware-using device. The contents can be rechecked by
2373 tristate "sysctl test driver"
2374 depends on PROC_SYSCTL
2376 This builds the "test_sysctl" module. This driver enables to test the
2377 proc sysctl interfaces available to drivers safely without affecting
2378 production knobs which might alter system functionality.
2382 config BITFIELD_KUNIT
2383 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2385 default KUNIT_ALL_TESTS
2387 Enable this option to test the bitfield functions at boot.
2389 KUnit tests run during boot and output the results to the debug log
2390 in TAP format (http://testanything.org/). Only useful for kernel devs
2391 running the KUnit test harness, and not intended for inclusion into a
2394 For more information on KUnit and unit tests in general please refer
2395 to the KUnit documentation in Documentation/dev-tools/kunit/.
2399 config HASH_KUNIT_TEST
2400 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2402 default KUNIT_ALL_TESTS
2404 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2405 integer (<linux/hash.h>) hash functions on boot.
2407 KUnit tests run during boot and output the results to the debug log
2408 in TAP format (https://testanything.org/). Only useful for kernel devs
2409 running the KUnit test harness, and not intended for inclusion into a
2412 For more information on KUnit and unit tests in general please refer
2413 to the KUnit documentation in Documentation/dev-tools/kunit/.
2415 This is intended to help people writing architecture-specific
2416 optimized versions. If unsure, say N.
2418 config RESOURCE_KUNIT_TEST
2419 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2421 default KUNIT_ALL_TESTS
2423 This builds the resource API unit test.
2424 Tests the logic of API provided by resource.c and ioport.h.
2425 For more information on KUnit and unit tests in general please refer
2426 to the KUnit documentation in Documentation/dev-tools/kunit/.
2430 config SYSCTL_KUNIT_TEST
2431 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2433 default KUNIT_ALL_TESTS
2435 This builds the proc sysctl unit test, which runs on boot.
2436 Tests the API contract and implementation correctness of sysctl.
2437 For more information on KUnit and unit tests in general please refer
2438 to the KUnit documentation in Documentation/dev-tools/kunit/.
2442 config LIST_KUNIT_TEST
2443 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2445 default KUNIT_ALL_TESTS
2447 This builds the linked list KUnit test suite.
2448 It tests that the API and basic functionality of the list_head type
2449 and associated macros.
2451 KUnit tests run during boot and output the results to the debug log
2452 in TAP format (https://testanything.org/). Only useful for kernel devs
2453 running the KUnit test harness, and not intended for inclusion into a
2456 For more information on KUnit and unit tests in general please refer
2457 to the KUnit documentation in Documentation/dev-tools/kunit/.
2461 config LINEAR_RANGES_TEST
2462 tristate "KUnit test for linear_ranges"
2464 select LINEAR_RANGES
2466 This builds the linear_ranges unit test, which runs on boot.
2467 Tests the linear_ranges logic correctness.
2468 For more information on KUnit and unit tests in general please refer
2469 to the KUnit documentation in Documentation/dev-tools/kunit/.
2473 config CMDLINE_KUNIT_TEST
2474 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2476 default KUNIT_ALL_TESTS
2478 This builds the cmdline API unit test.
2479 Tests the logic of API provided by cmdline.c.
2480 For more information on KUnit and unit tests in general please refer
2481 to the KUnit documentation in Documentation/dev-tools/kunit/.
2486 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2488 default KUNIT_ALL_TESTS
2490 This builds the bits unit test.
2491 Tests the logic of macros defined in bits.h.
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 SLUB_KUNIT_TEST
2498 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2499 depends on SLUB_DEBUG && KUNIT
2500 default KUNIT_ALL_TESTS
2502 This builds SLUB allocator unit test.
2503 Tests SLUB cache debugging functionality.
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 RATIONAL_KUNIT_TEST
2510 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2511 depends on KUNIT && RATIONAL
2512 default KUNIT_ALL_TESTS
2514 This builds the rational math unit test.
2515 For more information on KUnit and unit tests in general please refer
2516 to the KUnit documentation in Documentation/dev-tools/kunit/.
2520 config MEMCPY_KUNIT_TEST
2521 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2523 default KUNIT_ALL_TESTS
2525 Builds unit tests for memcpy(), memmove(), and memset() functions.
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 IS_SIGNED_TYPE_KUNIT_TEST
2532 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2534 default KUNIT_ALL_TESTS
2536 Builds unit tests for the is_signed_type() macro.
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 OVERFLOW_KUNIT_TEST
2544 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2546 default KUNIT_ALL_TESTS
2548 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2551 For more information on KUnit and unit tests in general please refer
2552 to the KUnit documentation in Documentation/dev-tools/kunit/.
2556 config STACKINIT_KUNIT_TEST
2557 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2559 default KUNIT_ALL_TESTS
2561 Test if the kernel is zero-initializing stack variables and
2562 padding. Coverage is controlled by compiler flags,
2563 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2564 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2565 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2567 config FORTIFY_KUNIT_TEST
2568 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2569 depends on KUNIT && FORTIFY_SOURCE
2570 default KUNIT_ALL_TESTS
2572 Builds unit tests for checking internals of FORTIFY_SOURCE as used
2573 by the str*() and mem*() family of functions. For testing runtime
2574 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2576 config HW_BREAKPOINT_KUNIT_TEST
2577 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2578 depends on HAVE_HW_BREAKPOINT
2580 default KUNIT_ALL_TESTS
2582 Tests for hw_breakpoint constraints accounting.
2587 tristate "udelay test driver"
2589 This builds the "udelay_test" module that helps to make sure
2590 that udelay() is working properly.
2594 config TEST_STATIC_KEYS
2595 tristate "Test static keys"
2598 Test the static key interfaces.
2602 config TEST_DYNAMIC_DEBUG
2603 tristate "Test DYNAMIC_DEBUG"
2604 depends on DYNAMIC_DEBUG
2606 This module registers a tracer callback to count enabled
2607 pr_debugs in a 'do_debugging' function, then alters their
2608 enablements, calls the function, and compares counts.
2613 tristate "kmod stress tester"
2615 depends on NETDEVICES && NET_CORE && INET # for TUN
2617 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2623 Test the kernel's module loading mechanism: kmod. kmod implements
2624 support to load modules using the Linux kernel's usermode helper.
2625 This test provides a series of tests against kmod.
2627 Although technically you can either build test_kmod as a module or
2628 into the kernel we disallow building it into the kernel since
2629 it stress tests request_module() and this will very likely cause
2630 some issues by taking over precious threads available from other
2631 module load requests, ultimately this could be fatal.
2635 tools/testing/selftests/kmod/kmod.sh --help
2639 config TEST_DEBUG_VIRTUAL
2640 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2641 depends on DEBUG_VIRTUAL
2643 Test the kernel's ability to detect incorrect calls to
2644 virt_to_phys() done against the non-linear part of the
2645 kernel's virtual address map.
2649 config TEST_MEMCAT_P
2650 tristate "Test memcat_p() helper function"
2652 Test the memcat_p() helper for correctly merging two
2653 pointer arrays together.
2657 config TEST_LIVEPATCH
2658 tristate "Test livepatching"
2660 depends on DYNAMIC_DEBUG
2661 depends on LIVEPATCH
2664 Test kernel livepatching features for correctness. The tests will
2665 load test modules that will be livepatched in various scenarios.
2667 To run all the livepatching tests:
2669 make -C tools/testing/selftests TARGETS=livepatch run_tests
2671 Alternatively, individual tests may be invoked:
2673 tools/testing/selftests/livepatch/test-callbacks.sh
2674 tools/testing/selftests/livepatch/test-livepatch.sh
2675 tools/testing/selftests/livepatch/test-shadow-vars.sh
2680 tristate "Perform selftest on object aggreration manager"
2684 Enable this option to test object aggregation manager on boot
2688 tristate "Test heap/page initialization"
2690 Test if the kernel is zero-initializing heap and page allocations.
2691 This can be useful to test init_on_alloc and init_on_free features.
2696 tristate "Test HMM (Heterogeneous Memory Management)"
2697 depends on TRANSPARENT_HUGEPAGE
2698 depends on DEVICE_PRIVATE
2702 This is a pseudo device driver solely for testing HMM.
2703 Say M here if you want to build the HMM test module.
2704 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2708 config TEST_FREE_PAGES
2709 tristate "Test freeing pages"
2711 Test that a memory leak does not occur due to a race between
2712 freeing a block of pages and a speculative page reference.
2713 Loading this module is safe if your kernel has the bug fixed.
2714 If the bug is not fixed, it will leak gigabytes of memory and
2715 probably OOM your system.
2718 tristate "Test floating point operations in kernel space"
2719 depends on X86 && !KCOV_INSTRUMENT_ALL
2721 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2722 which will trigger a sequence of floating point operations. This is used
2723 for self-testing floating point control register setting in
2728 config TEST_CLOCKSOURCE_WATCHDOG
2729 tristate "Test clocksource watchdog in kernel space"
2730 depends on CLOCKSOURCE_WATCHDOG
2732 Enable this option to create a kernel module that will trigger
2733 a test of the clocksource watchdog. This module may be loaded
2734 via modprobe or insmod in which case it will run upon being
2735 loaded, or it may be built in, in which case it will run
2740 endif # RUNTIME_TESTING_MENU
2742 config ARCH_USE_MEMTEST
2745 An architecture should select this when it uses early_memtest()
2746 during boot process.
2750 depends on ARCH_USE_MEMTEST
2752 This option adds a kernel parameter 'memtest', which allows memtest
2753 to be set and executed.
2754 memtest=0, mean disabled; -- default
2755 memtest=1, mean do 1 test pattern;
2757 memtest=17, mean do 17 test patterns.
2758 If you are unsure how to answer this question, answer N.
2762 config HYPERV_TESTING
2763 bool "Microsoft Hyper-V driver testing"
2765 depends on HYPERV && DEBUG_FS
2767 Select this option to enable Hyper-V vmbus testing.
2769 endmenu # "Kernel Testing and Coverage"
2773 config RUST_DEBUG_ASSERTIONS
2774 bool "Debug assertions"
2777 Enables rustc's `-Cdebug-assertions` codegen option.
2779 This flag lets you turn `cfg(debug_assertions)` conditional
2780 compilation on or off. This can be used to enable extra debugging
2781 code in development but not in production. For example, it controls
2782 the behavior of the standard library's `debug_assert!` macro.
2784 Note that this will apply to all Rust code, including `core`.
2788 config RUST_OVERFLOW_CHECKS
2789 bool "Overflow checks"
2793 Enables rustc's `-Coverflow-checks` codegen option.
2795 This flag allows you to control the behavior of runtime integer
2796 overflow. When overflow-checks are enabled, a Rust panic will occur
2799 Note that this will apply to all Rust code, including `core`.
2805 source "Documentation/Kconfig"
2807 endmenu # Kernel hacking
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