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"
399 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
400 default 2048 if PARISC
401 default 1536 if (!64BIT && XTENSA)
402 default 1024 if !64BIT
403 default 2048 if 64BIT
405 Tell the compiler to warn at build time for stack frames larger than this.
406 Setting this too low will cause a lot of warnings.
407 Setting it to 0 disables the warning.
409 config STRIP_ASM_SYMS
410 bool "Strip assembler-generated symbols during link"
413 Strip internal assembler-generated symbols during a link (symbols
414 that look like '.Lxxx') so they don't pollute the output of
415 get_wchan() and suchlike.
418 bool "Generate readable assembler code"
419 depends on DEBUG_KERNEL
422 Disable some compiler optimizations that tend to generate human unreadable
423 assembler output. This may make the kernel slightly slower, but it helps
424 to keep kernel developers who have to stare a lot at assembler listings
427 config HEADERS_INSTALL
428 bool "Install uapi headers to usr/include"
431 This option will install uapi headers (headers exported to user-space)
432 into the usr/include directory for use during the kernel build.
433 This is unneeded for building the kernel itself, but needed for some
434 user-space program samples. It is also needed by some features such
435 as uapi header sanity checks.
437 config DEBUG_SECTION_MISMATCH
438 bool "Enable full Section mismatch analysis"
441 The section mismatch analysis checks if there are illegal
442 references from one section to another section.
443 During linktime or runtime, some sections are dropped;
444 any use of code/data previously in these sections would
445 most likely result in an oops.
446 In the code, functions and variables are annotated with
447 __init,, etc. (see the full list in include/linux/init.h),
448 which results in the code/data being placed in specific sections.
449 The section mismatch analysis is always performed after a full
450 kernel build, and enabling this option causes the following
451 additional step to occur:
452 - Add the option -fno-inline-functions-called-once to gcc commands.
453 When inlining a function annotated with __init in a non-init
454 function, we would lose the section information and thus
455 the analysis would not catch the illegal reference.
456 This option tells gcc to inline less (but it does result in
459 config SECTION_MISMATCH_WARN_ONLY
460 bool "Make section mismatch errors non-fatal"
463 If you say N here, the build process will fail if there are any
464 section mismatch, instead of just throwing warnings.
468 config DEBUG_FORCE_FUNCTION_ALIGN_64B
469 bool "Force all function address 64B aligned"
470 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC)
472 There are cases that a commit from one domain changes the function
473 address alignment of other domains, and cause magic performance
474 bump (regression or improvement). Enable this option will help to
475 verify if the bump is caused by function alignment changes, while
476 it will slightly increase the kernel size and affect icache usage.
478 It is mainly for debug and performance tuning use.
481 # Select this config option from the architecture Kconfig, if it
482 # is preferred to always offer frame pointers as a config
483 # option on the architecture (regardless of KERNEL_DEBUG):
485 config ARCH_WANT_FRAME_POINTERS
489 bool "Compile the kernel with frame pointers"
490 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
491 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
493 If you say Y here the resulting kernel image will be slightly
494 larger and slower, but it gives very useful debugging information
495 in case of kernel bugs. (precise oopses/stacktraces/warnings)
500 config STACK_VALIDATION
501 bool "Compile-time stack metadata validation"
502 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
506 Validate frame pointer rules at compile-time. This helps ensure that
507 runtime stack traces are more reliable.
509 For more information, see
510 tools/objtool/Documentation/objtool.txt.
512 config NOINSTR_VALIDATION
514 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
519 bool "Generate vmlinux.map file when linking"
522 Selecting this option will pass "-Map=vmlinux.map" to ld
523 when linking vmlinux. That file can be useful for verifying
524 and debugging magic section games, and for seeing which
525 pieces of code get eliminated with
526 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
528 config DEBUG_FORCE_WEAK_PER_CPU
529 bool "Force weak per-cpu definitions"
530 depends on DEBUG_KERNEL
532 s390 and alpha require percpu variables in modules to be
533 defined weak to work around addressing range issue which
534 puts the following two restrictions on percpu variable
537 1. percpu symbols must be unique whether static or not
538 2. percpu variables can't be defined inside a function
540 To ensure that generic code follows the above rules, this
541 option forces all percpu variables to be defined as weak.
543 endmenu # "Compiler options"
545 menu "Generic Kernel Debugging Instruments"
548 bool "Magic SysRq key"
551 If you say Y here, you will have some control over the system even
552 if the system crashes for example during kernel debugging (e.g., you
553 will be able to flush the buffer cache to disk, reboot the system
554 immediately or dump some status information). This is accomplished
555 by pressing various keys while holding SysRq (Alt+PrintScreen). It
556 also works on a serial console (on PC hardware at least), if you
557 send a BREAK and then within 5 seconds a command keypress. The
558 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
559 Don't say Y unless you really know what this hack does.
561 config MAGIC_SYSRQ_DEFAULT_ENABLE
562 hex "Enable magic SysRq key functions by default"
563 depends on MAGIC_SYSRQ
566 Specifies which SysRq key functions are enabled by default.
567 This may be set to 1 or 0 to enable or disable them all, or
568 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
570 config MAGIC_SYSRQ_SERIAL
571 bool "Enable magic SysRq key over serial"
572 depends on MAGIC_SYSRQ
575 Many embedded boards have a disconnected TTL level serial which can
576 generate some garbage that can lead to spurious false sysrq detects.
577 This option allows you to decide whether you want to enable the
580 config MAGIC_SYSRQ_SERIAL_SEQUENCE
581 string "Char sequence that enables magic SysRq over serial"
582 depends on MAGIC_SYSRQ_SERIAL
585 Specifies a sequence of characters that can follow BREAK to enable
586 SysRq on a serial console.
588 If unsure, leave an empty string and the option will not be enabled.
591 bool "Debug Filesystem"
593 debugfs is a virtual file system that kernel developers use to put
594 debugging files into. Enable this option to be able to read and
595 write to these files.
597 For detailed documentation on the debugfs API, see
598 Documentation/filesystems/.
603 prompt "Debugfs default access"
605 default DEBUG_FS_ALLOW_ALL
607 This selects the default access restrictions for debugfs.
608 It can be overridden with kernel command line option
609 debugfs=[on,no-mount,off]. The restrictions apply for API access
610 and filesystem registration.
612 config DEBUG_FS_ALLOW_ALL
615 No restrictions apply. Both API and filesystem registration
616 is on. This is the normal default operation.
618 config DEBUG_FS_DISALLOW_MOUNT
619 bool "Do not register debugfs as filesystem"
621 The API is open but filesystem is not loaded. Clients can still do
622 their work and read with debug tools that do not need
625 config DEBUG_FS_ALLOW_NONE
628 Access is off. Clients get -PERM when trying to create nodes in
629 debugfs tree and debugfs is not registered as a filesystem.
630 Client can then back-off or continue without debugfs access.
634 source "lib/Kconfig.kgdb"
635 source "lib/Kconfig.ubsan"
636 source "lib/Kconfig.kcsan"
640 menu "Networking Debugging"
642 source "net/Kconfig.debug"
644 endmenu # "Networking Debugging"
646 menu "Memory Debugging"
648 source "mm/Kconfig.debug"
651 bool "Debug object operations"
652 depends on DEBUG_KERNEL
654 If you say Y here, additional code will be inserted into the
655 kernel to track the life time of various objects and validate
656 the operations on those objects.
658 config DEBUG_OBJECTS_SELFTEST
659 bool "Debug objects selftest"
660 depends on DEBUG_OBJECTS
662 This enables the selftest of the object debug code.
664 config DEBUG_OBJECTS_FREE
665 bool "Debug objects in freed memory"
666 depends on DEBUG_OBJECTS
668 This enables checks whether a k/v free operation frees an area
669 which contains an object which has not been deactivated
670 properly. This can make kmalloc/kfree-intensive workloads
673 config DEBUG_OBJECTS_TIMERS
674 bool "Debug timer objects"
675 depends on DEBUG_OBJECTS
677 If you say Y here, additional code will be inserted into the
678 timer routines to track the life time of timer objects and
679 validate the timer operations.
681 config DEBUG_OBJECTS_WORK
682 bool "Debug work objects"
683 depends on DEBUG_OBJECTS
685 If you say Y here, additional code will be inserted into the
686 work queue routines to track the life time of work objects and
687 validate the work operations.
689 config DEBUG_OBJECTS_RCU_HEAD
690 bool "Debug RCU callbacks objects"
691 depends on DEBUG_OBJECTS
693 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
695 config DEBUG_OBJECTS_PERCPU_COUNTER
696 bool "Debug percpu counter objects"
697 depends on DEBUG_OBJECTS
699 If you say Y here, additional code will be inserted into the
700 percpu counter routines to track the life time of percpu counter
701 objects and validate the percpu counter operations.
703 config DEBUG_OBJECTS_ENABLE_DEFAULT
704 int "debug_objects bootup default value (0-1)"
707 depends on DEBUG_OBJECTS
709 Debug objects boot parameter default value
711 config SHRINKER_DEBUG
712 bool "Enable shrinker debugging support"
715 Say Y to enable the shrinker debugfs interface which provides
716 visibility into the kernel memory shrinkers subsystem.
717 Disable it to avoid an extra memory footprint.
719 config HAVE_DEBUG_KMEMLEAK
722 config DEBUG_KMEMLEAK
723 bool "Kernel memory leak detector"
724 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
726 select STACKTRACE if STACKTRACE_SUPPORT
730 Say Y here if you want to enable the memory leak
731 detector. The memory allocation/freeing is traced in a way
732 similar to the Boehm's conservative garbage collector, the
733 difference being that the orphan objects are not freed but
734 only shown in /sys/kernel/debug/kmemleak. Enabling this
735 feature will introduce an overhead to memory
736 allocations. See Documentation/dev-tools/kmemleak.rst for more
739 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
740 of finding leaks due to the slab objects poisoning.
742 In order to access the kmemleak file, debugfs needs to be
743 mounted (usually at /sys/kernel/debug).
745 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
746 int "Kmemleak memory pool size"
747 depends on DEBUG_KMEMLEAK
751 Kmemleak must track all the memory allocations to avoid
752 reporting false positives. Since memory may be allocated or
753 freed before kmemleak is fully initialised, use a static pool
754 of metadata objects to track such callbacks. After kmemleak is
755 fully initialised, this memory pool acts as an emergency one
756 if slab allocations fail.
758 config DEBUG_KMEMLEAK_TEST
759 tristate "Simple test for the kernel memory leak detector"
760 depends on DEBUG_KMEMLEAK && m
762 This option enables a module that explicitly leaks memory.
766 config DEBUG_KMEMLEAK_DEFAULT_OFF
767 bool "Default kmemleak to off"
768 depends on DEBUG_KMEMLEAK
770 Say Y here to disable kmemleak by default. It can then be enabled
771 on the command line via kmemleak=on.
773 config DEBUG_KMEMLEAK_AUTO_SCAN
774 bool "Enable kmemleak auto scan thread on boot up"
776 depends on DEBUG_KMEMLEAK
778 Depending on the cpu, kmemleak scan may be cpu intensive and can
779 stall user tasks at times. This option enables/disables automatic
780 kmemleak scan at boot up.
782 Say N here to disable kmemleak auto scan thread to stop automatic
783 scanning. Disabling this option disables automatic reporting of
788 config DEBUG_STACK_USAGE
789 bool "Stack utilization instrumentation"
790 depends on DEBUG_KERNEL && !IA64
792 Enables the display of the minimum amount of free stack which each
793 task has ever had available in the sysrq-T and sysrq-P debug output.
795 This option will slow down process creation somewhat.
797 config SCHED_STACK_END_CHECK
798 bool "Detect stack corruption on calls to schedule()"
799 depends on DEBUG_KERNEL
802 This option checks for a stack overrun on calls to schedule().
803 If the stack end location is found to be over written always panic as
804 the content of the corrupted region can no longer be trusted.
805 This is to ensure no erroneous behaviour occurs which could result in
806 data corruption or a sporadic crash at a later stage once the region
807 is examined. The runtime overhead introduced is minimal.
809 config ARCH_HAS_DEBUG_VM_PGTABLE
812 An architecture should select this when it can successfully
813 build and run DEBUG_VM_PGTABLE.
815 config DEBUG_VM_IRQSOFF
816 def_bool DEBUG_VM && !PREEMPT_RT
820 depends on DEBUG_KERNEL
822 Enable this to turn on extended checks in the virtual-memory system
823 that may impact performance.
827 config DEBUG_VM_MAPLE_TREE
828 bool "Debug VM maple trees"
830 select DEBUG_MAPLE_TREE
832 Enable VM maple tree debugging information and extra validations.
837 bool "Debug VM red-black trees"
840 Enable VM red-black tree debugging information and extra validations.
844 config DEBUG_VM_PGFLAGS
845 bool "Debug page-flags operations"
848 Enables extra validation on page flags operations.
852 config DEBUG_VM_PGTABLE
853 bool "Debug arch page table for semantics compliance"
855 depends on ARCH_HAS_DEBUG_VM_PGTABLE
856 default y if DEBUG_VM
858 This option provides a debug method which can be used to test
859 architecture page table helper functions on various platforms in
860 verifying if they comply with expected generic MM semantics. This
861 will help architecture code in making sure that any changes or
862 new additions of these helpers still conform to expected
863 semantics of the generic MM. Platforms will have to opt in for
864 this through ARCH_HAS_DEBUG_VM_PGTABLE.
868 config ARCH_HAS_DEBUG_VIRTUAL
872 bool "Debug VM translations"
873 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
875 Enable some costly sanity checks in virtual to page code. This can
876 catch mistakes with virt_to_page() and friends.
880 config DEBUG_NOMMU_REGIONS
881 bool "Debug the global anon/private NOMMU mapping region tree"
882 depends on DEBUG_KERNEL && !MMU
884 This option causes the global tree of anonymous and private mapping
885 regions to be regularly checked for invalid topology.
887 config DEBUG_MEMORY_INIT
888 bool "Debug memory initialisation" if EXPERT
891 Enable this for additional checks during memory initialisation.
892 The sanity checks verify aspects of the VM such as the memory model
893 and other information provided by the architecture. Verbose
894 information will be printed at KERN_DEBUG loglevel depending
895 on the mminit_loglevel= command-line option.
899 config MEMORY_NOTIFIER_ERROR_INJECT
900 tristate "Memory hotplug notifier error injection module"
901 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
903 This option provides the ability to inject artificial errors to
904 memory hotplug notifier chain callbacks. It is controlled through
905 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
907 If the notifier call chain should be failed with some events
908 notified, write the error code to "actions/<notifier event>/error".
910 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
912 # cd /sys/kernel/debug/notifier-error-inject/memory
913 # echo -12 > actions/MEM_GOING_OFFLINE/error
914 # echo offline > /sys/devices/system/memory/memoryXXX/state
915 bash: echo: write error: Cannot allocate memory
917 To compile this code as a module, choose M here: the module will
918 be called memory-notifier-error-inject.
922 config DEBUG_PER_CPU_MAPS
923 bool "Debug access to per_cpu maps"
924 depends on DEBUG_KERNEL
927 Say Y to verify that the per_cpu map being accessed has
928 been set up. This adds a fair amount of code to kernel memory
929 and decreases performance.
933 config DEBUG_KMAP_LOCAL
934 bool "Debug kmap_local temporary mappings"
935 depends on DEBUG_KERNEL && KMAP_LOCAL
937 This option enables additional error checking for the kmap_local
938 infrastructure. Disable for production use.
940 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
943 config DEBUG_KMAP_LOCAL_FORCE_MAP
944 bool "Enforce kmap_local temporary mappings"
945 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
947 select DEBUG_KMAP_LOCAL
949 This option enforces temporary mappings through the kmap_local
950 mechanism for non-highmem pages and on non-highmem systems.
951 Disable this for production systems!
954 bool "Highmem debugging"
955 depends on DEBUG_KERNEL && HIGHMEM
956 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
957 select DEBUG_KMAP_LOCAL
959 This option enables additional error checking for high memory
960 systems. Disable for production systems.
962 config HAVE_DEBUG_STACKOVERFLOW
965 config DEBUG_STACKOVERFLOW
966 bool "Check for stack overflows"
967 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
969 Say Y here if you want to check for overflows of kernel, IRQ
970 and exception stacks (if your architecture uses them). This
971 option will show detailed messages if free stack space drops
972 below a certain limit.
974 These kinds of bugs usually occur when call-chains in the
975 kernel get too deep, especially when interrupts are
978 Use this in cases where you see apparently random memory
979 corruption, especially if it appears in 'struct thread_info'
981 If in doubt, say "N".
983 source "lib/Kconfig.kasan"
984 source "lib/Kconfig.kfence"
985 source "lib/Kconfig.kmsan"
987 endmenu # "Memory Debugging"
990 bool "Debug shared IRQ handlers"
991 depends on DEBUG_KERNEL
993 Enable this to generate a spurious interrupt just before a shared
994 interrupt handler is deregistered (generating one when registering
995 is currently disabled). Drivers need to handle this correctly. Some
996 don't and need to be caught.
998 menu "Debug Oops, Lockups and Hangs"
1000 config PANIC_ON_OOPS
1001 bool "Panic on Oops"
1003 Say Y here to enable the kernel to panic when it oopses. This
1004 has the same effect as setting oops=panic on the kernel command
1007 This feature is useful to ensure that the kernel does not do
1008 anything erroneous after an oops which could result in data
1009 corruption or other issues.
1013 config PANIC_ON_OOPS_VALUE
1016 default 0 if !PANIC_ON_OOPS
1017 default 1 if PANIC_ON_OOPS
1019 config PANIC_TIMEOUT
1023 Set the timeout value (in seconds) until a reboot occurs when
1024 the kernel panics. If n = 0, then we wait forever. A timeout
1025 value n > 0 will wait n seconds before rebooting, while a timeout
1026 value n < 0 will reboot immediately.
1028 config LOCKUP_DETECTOR
1031 config SOFTLOCKUP_DETECTOR
1032 bool "Detect Soft Lockups"
1033 depends on DEBUG_KERNEL && !S390
1034 select LOCKUP_DETECTOR
1036 Say Y here to enable the kernel to act as a watchdog to detect
1039 Softlockups are bugs that cause the kernel to loop in kernel
1040 mode for more than 20 seconds, without giving other tasks a
1041 chance to run. The current stack trace is displayed upon
1042 detection and the system will stay locked up.
1044 config BOOTPARAM_SOFTLOCKUP_PANIC
1045 bool "Panic (Reboot) On Soft Lockups"
1046 depends on SOFTLOCKUP_DETECTOR
1048 Say Y here to enable the kernel to panic on "soft lockups",
1049 which are bugs that cause the kernel to loop in kernel
1050 mode for more than 20 seconds (configurable using the watchdog_thresh
1051 sysctl), without giving other tasks a chance to run.
1053 The panic can be used in combination with panic_timeout,
1054 to cause the system to reboot automatically after a
1055 lockup has been detected. This feature is useful for
1056 high-availability systems that have uptime guarantees and
1057 where a lockup must be resolved ASAP.
1061 config HARDLOCKUP_DETECTOR_PERF
1063 select SOFTLOCKUP_DETECTOR
1066 # Enables a timestamp based low pass filter to compensate for perf based
1067 # hard lockup detection which runs too fast due to turbo modes.
1069 config HARDLOCKUP_CHECK_TIMESTAMP
1073 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1074 # lockup detector rather than the perf based detector.
1076 config HARDLOCKUP_DETECTOR
1077 bool "Detect Hard Lockups"
1078 depends on DEBUG_KERNEL && !S390
1079 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1080 select LOCKUP_DETECTOR
1081 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1083 Say Y here to enable the kernel to act as a watchdog to detect
1086 Hardlockups are bugs that cause the CPU to loop in kernel mode
1087 for more than 10 seconds, without letting other interrupts have a
1088 chance to run. The current stack trace is displayed upon detection
1089 and the system will stay locked up.
1091 config BOOTPARAM_HARDLOCKUP_PANIC
1092 bool "Panic (Reboot) On Hard Lockups"
1093 depends on HARDLOCKUP_DETECTOR
1095 Say Y here to enable the kernel to panic on "hard lockups",
1096 which are bugs that cause the kernel to loop in kernel
1097 mode with interrupts disabled for more than 10 seconds (configurable
1098 using the watchdog_thresh sysctl).
1102 config DETECT_HUNG_TASK
1103 bool "Detect Hung Tasks"
1104 depends on DEBUG_KERNEL
1105 default SOFTLOCKUP_DETECTOR
1107 Say Y here to enable the kernel to detect "hung tasks",
1108 which are bugs that cause the task to be stuck in
1109 uninterruptible "D" state indefinitely.
1111 When a hung task is detected, the kernel will print the
1112 current stack trace (which you should report), but the
1113 task will stay in uninterruptible state. If lockdep is
1114 enabled then all held locks will also be reported. This
1115 feature has negligible overhead.
1117 config DEFAULT_HUNG_TASK_TIMEOUT
1118 int "Default timeout for hung task detection (in seconds)"
1119 depends on DETECT_HUNG_TASK
1122 This option controls the default timeout (in seconds) used
1123 to determine when a task has become non-responsive and should
1126 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1127 sysctl or by writing a value to
1128 /proc/sys/kernel/hung_task_timeout_secs.
1130 A timeout of 0 disables the check. The default is two minutes.
1131 Keeping the default should be fine in most cases.
1133 config BOOTPARAM_HUNG_TASK_PANIC
1134 bool "Panic (Reboot) On Hung Tasks"
1135 depends on DETECT_HUNG_TASK
1137 Say Y here to enable the kernel to panic on "hung tasks",
1138 which are bugs that cause the kernel to leave a task stuck
1139 in uninterruptible "D" state.
1141 The panic can be used in combination with panic_timeout,
1142 to cause the system to reboot automatically after a
1143 hung task has been detected. This feature is useful for
1144 high-availability systems that have uptime guarantees and
1145 where a hung tasks must be resolved ASAP.
1150 bool "Detect Workqueue Stalls"
1151 depends on DEBUG_KERNEL
1153 Say Y here to enable stall detection on workqueues. If a
1154 worker pool doesn't make forward progress on a pending work
1155 item for over a given amount of time, 30s by default, a
1156 warning message is printed along with dump of workqueue
1157 state. This can be configured through kernel parameter
1158 "workqueue.watchdog_thresh" and its sysfs counterpart.
1161 tristate "Test module to generate lockups"
1164 This builds the "test_lockup" module that helps to make sure
1165 that watchdogs and lockup detectors are working properly.
1167 Depending on module parameters it could emulate soft or hard
1168 lockup, "hung task", or locking arbitrary lock for a long time.
1169 Also it could generate series of lockups with cooling-down periods.
1173 endmenu # "Debug lockups and hangs"
1175 menu "Scheduler Debugging"
1178 bool "Collect scheduler debugging info"
1179 depends on DEBUG_KERNEL && PROC_FS
1182 If you say Y here, the /proc/sched_debug file will be provided
1183 that can help debug the scheduler. The runtime overhead of this
1191 bool "Collect scheduler statistics"
1192 depends on DEBUG_KERNEL && PROC_FS
1195 If you say Y here, additional code will be inserted into the
1196 scheduler and related routines to collect statistics about
1197 scheduler behavior and provide them in /proc/schedstat. These
1198 stats may be useful for both tuning and debugging the scheduler
1199 If you aren't debugging the scheduler or trying to tune a specific
1200 application, you can say N to avoid the very slight overhead
1205 config DEBUG_TIMEKEEPING
1206 bool "Enable extra timekeeping sanity checking"
1208 This option will enable additional timekeeping sanity checks
1209 which may be helpful when diagnosing issues where timekeeping
1210 problems are suspected.
1212 This may include checks in the timekeeping hotpaths, so this
1213 option may have a (very small) performance impact to some
1218 config DEBUG_PREEMPT
1219 bool "Debug preemptible kernel"
1220 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1223 If you say Y here then the kernel will use a debug variant of the
1224 commonly used smp_processor_id() function and will print warnings
1225 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1226 will detect preemption count underflows.
1228 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1230 config LOCK_DEBUGGING_SUPPORT
1232 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1235 config PROVE_LOCKING
1236 bool "Lock debugging: prove locking correctness"
1237 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1239 select DEBUG_SPINLOCK
1240 select DEBUG_MUTEXES if !PREEMPT_RT
1241 select DEBUG_RT_MUTEXES if RT_MUTEXES
1243 select DEBUG_WW_MUTEX_SLOWPATH
1244 select DEBUG_LOCK_ALLOC
1245 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1246 select TRACE_IRQFLAGS
1249 This feature enables the kernel to prove that all locking
1250 that occurs in the kernel runtime is mathematically
1251 correct: that under no circumstance could an arbitrary (and
1252 not yet triggered) combination of observed locking
1253 sequences (on an arbitrary number of CPUs, running an
1254 arbitrary number of tasks and interrupt contexts) cause a
1257 In short, this feature enables the kernel to report locking
1258 related deadlocks before they actually occur.
1260 The proof does not depend on how hard and complex a
1261 deadlock scenario would be to trigger: how many
1262 participant CPUs, tasks and irq-contexts would be needed
1263 for it to trigger. The proof also does not depend on
1264 timing: if a race and a resulting deadlock is possible
1265 theoretically (no matter how unlikely the race scenario
1266 is), it will be proven so and will immediately be
1267 reported by the kernel (once the event is observed that
1268 makes the deadlock theoretically possible).
1270 If a deadlock is impossible (i.e. the locking rules, as
1271 observed by the kernel, are mathematically correct), the
1272 kernel reports nothing.
1274 NOTE: this feature can also be enabled for rwlocks, mutexes
1275 and rwsems - in which case all dependencies between these
1276 different locking variants are observed and mapped too, and
1277 the proof of observed correctness is also maintained for an
1278 arbitrary combination of these separate locking variants.
1280 For more details, see Documentation/locking/lockdep-design.rst.
1282 config PROVE_RAW_LOCK_NESTING
1283 bool "Enable raw_spinlock - spinlock nesting checks"
1284 depends on PROVE_LOCKING
1287 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1288 that the lock nesting rules for PREEMPT_RT enabled kernels are
1291 NOTE: There are known nesting problems. So if you enable this
1292 option expect lockdep splats until these problems have been fully
1293 addressed which is work in progress. This config switch allows to
1294 identify and analyze these problems. It will be removed and the
1295 check permanently enabled once the main issues have been fixed.
1297 If unsure, select N.
1300 bool "Lock usage statistics"
1301 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1303 select DEBUG_SPINLOCK
1304 select DEBUG_MUTEXES if !PREEMPT_RT
1305 select DEBUG_RT_MUTEXES if RT_MUTEXES
1306 select DEBUG_LOCK_ALLOC
1309 This feature enables tracking lock contention points
1311 For more details, see Documentation/locking/lockstat.rst
1313 This also enables lock events required by "perf lock",
1315 If you want to use "perf lock", you also need to turn on
1316 CONFIG_EVENT_TRACING.
1318 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1319 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1321 config DEBUG_RT_MUTEXES
1322 bool "RT Mutex debugging, deadlock detection"
1323 depends on DEBUG_KERNEL && RT_MUTEXES
1325 This allows rt mutex semantics violations and rt mutex related
1326 deadlocks (lockups) to be detected and reported automatically.
1328 config DEBUG_SPINLOCK
1329 bool "Spinlock and rw-lock debugging: basic checks"
1330 depends on DEBUG_KERNEL
1331 select UNINLINE_SPIN_UNLOCK
1333 Say Y here and build SMP to catch missing spinlock initialization
1334 and certain other kinds of spinlock errors commonly made. This is
1335 best used in conjunction with the NMI watchdog so that spinlock
1336 deadlocks are also debuggable.
1338 config DEBUG_MUTEXES
1339 bool "Mutex debugging: basic checks"
1340 depends on DEBUG_KERNEL && !PREEMPT_RT
1342 This feature allows mutex semantics violations to be detected and
1345 config DEBUG_WW_MUTEX_SLOWPATH
1346 bool "Wait/wound mutex debugging: Slowpath testing"
1347 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1348 select DEBUG_LOCK_ALLOC
1349 select DEBUG_SPINLOCK
1350 select DEBUG_MUTEXES if !PREEMPT_RT
1351 select DEBUG_RT_MUTEXES if PREEMPT_RT
1353 This feature enables slowpath testing for w/w mutex users by
1354 injecting additional -EDEADLK wound/backoff cases. Together with
1355 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1356 will test all possible w/w mutex interface abuse with the
1357 exception of simply not acquiring all the required locks.
1358 Note that this feature can introduce significant overhead, so
1359 it really should not be enabled in a production or distro kernel,
1360 even a debug kernel. If you are a driver writer, enable it. If
1361 you are a distro, do not.
1364 bool "RW Semaphore debugging: basic checks"
1365 depends on DEBUG_KERNEL
1367 This debugging feature allows mismatched rw semaphore locks
1368 and unlocks to be detected and reported.
1370 config DEBUG_LOCK_ALLOC
1371 bool "Lock debugging: detect incorrect freeing of live locks"
1372 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1373 select DEBUG_SPINLOCK
1374 select DEBUG_MUTEXES if !PREEMPT_RT
1375 select DEBUG_RT_MUTEXES if RT_MUTEXES
1378 This feature will check whether any held lock (spinlock, rwlock,
1379 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1380 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1381 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1382 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1383 held during task exit.
1387 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1392 config LOCKDEP_SMALL
1396 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1397 depends on LOCKDEP && !LOCKDEP_SMALL
1401 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1403 config LOCKDEP_CHAINS_BITS
1404 int "Bitsize for MAX_LOCKDEP_CHAINS"
1405 depends on LOCKDEP && !LOCKDEP_SMALL
1409 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1411 config LOCKDEP_STACK_TRACE_BITS
1412 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1413 depends on LOCKDEP && !LOCKDEP_SMALL
1417 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1419 config LOCKDEP_STACK_TRACE_HASH_BITS
1420 int "Bitsize for STACK_TRACE_HASH_SIZE"
1421 depends on LOCKDEP && !LOCKDEP_SMALL
1425 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1427 config LOCKDEP_CIRCULAR_QUEUE_BITS
1428 int "Bitsize for elements in circular_queue struct"
1433 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1435 config DEBUG_LOCKDEP
1436 bool "Lock dependency engine debugging"
1437 depends on DEBUG_KERNEL && LOCKDEP
1438 select DEBUG_IRQFLAGS
1440 If you say Y here, the lock dependency engine will do
1441 additional runtime checks to debug itself, at the price
1442 of more runtime overhead.
1444 config DEBUG_ATOMIC_SLEEP
1445 bool "Sleep inside atomic section checking"
1446 select PREEMPT_COUNT
1447 depends on DEBUG_KERNEL
1448 depends on !ARCH_NO_PREEMPT
1450 If you say Y here, various routines which may sleep will become very
1451 noisy if they are called inside atomic sections: when a spinlock is
1452 held, inside an rcu read side critical section, inside preempt disabled
1453 sections, inside an interrupt, etc...
1455 config DEBUG_LOCKING_API_SELFTESTS
1456 bool "Locking API boot-time self-tests"
1457 depends on DEBUG_KERNEL
1459 Say Y here if you want the kernel to run a short self-test during
1460 bootup. The self-test checks whether common types of locking bugs
1461 are detected by debugging mechanisms or not. (if you disable
1462 lock debugging then those bugs won't be detected of course.)
1463 The following locking APIs are covered: spinlocks, rwlocks,
1466 config LOCK_TORTURE_TEST
1467 tristate "torture tests for locking"
1468 depends on DEBUG_KERNEL
1471 This option provides a kernel module that runs torture tests
1472 on kernel locking primitives. The kernel module may be built
1473 after the fact on the running kernel to be tested, if desired.
1475 Say Y here if you want kernel locking-primitive torture tests
1476 to be built into the kernel.
1477 Say M if you want these torture tests to build as a module.
1478 Say N if you are unsure.
1480 config WW_MUTEX_SELFTEST
1481 tristate "Wait/wound mutex selftests"
1483 This option provides a kernel module that runs tests on the
1484 on the struct ww_mutex locking API.
1486 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1487 with this test harness.
1489 Say M if you want these self tests to build as a module.
1490 Say N if you are unsure.
1492 config SCF_TORTURE_TEST
1493 tristate "torture tests for smp_call_function*()"
1494 depends on DEBUG_KERNEL
1497 This option provides a kernel module that runs torture tests
1498 on the smp_call_function() family of primitives. The kernel
1499 module may be built after the fact on the running kernel to
1500 be tested, if desired.
1502 config CSD_LOCK_WAIT_DEBUG
1503 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1504 depends on DEBUG_KERNEL
1508 This option enables debug prints when CPUs are slow to respond
1509 to the smp_call_function*() IPI wrappers. These debug prints
1510 include the IPI handler function currently executing (if any)
1511 and relevant stack traces.
1513 endmenu # lock debugging
1515 config TRACE_IRQFLAGS
1516 depends on TRACE_IRQFLAGS_SUPPORT
1519 Enables hooks to interrupt enabling and disabling for
1520 either tracing or lock debugging.
1522 config TRACE_IRQFLAGS_NMI
1524 depends on TRACE_IRQFLAGS
1525 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1527 config DEBUG_IRQFLAGS
1528 bool "Debug IRQ flag manipulation"
1530 Enables checks for potentially unsafe enabling or disabling of
1531 interrupts, such as calling raw_local_irq_restore() when interrupts
1535 bool "Stack backtrace support"
1536 depends on STACKTRACE_SUPPORT
1538 This option causes the kernel to create a /proc/pid/stack for
1539 every process, showing its current stack trace.
1540 It is also used by various kernel debugging features that require
1541 stack trace generation.
1543 config WARN_ALL_UNSEEDED_RANDOM
1544 bool "Warn for all uses of unseeded randomness"
1547 Some parts of the kernel contain bugs relating to their use of
1548 cryptographically secure random numbers before it's actually possible
1549 to generate those numbers securely. This setting ensures that these
1550 flaws don't go unnoticed, by enabling a message, should this ever
1551 occur. This will allow people with obscure setups to know when things
1552 are going wrong, so that they might contact developers about fixing
1555 Unfortunately, on some models of some architectures getting
1556 a fully seeded CRNG is extremely difficult, and so this can
1557 result in dmesg getting spammed for a surprisingly long
1558 time. This is really bad from a security perspective, and
1559 so architecture maintainers really need to do what they can
1560 to get the CRNG seeded sooner after the system is booted.
1561 However, since users cannot do anything actionable to
1562 address this, by default this option is disabled.
1564 Say Y here if you want to receive warnings for all uses of
1565 unseeded randomness. This will be of use primarily for
1566 those developers interested in improving the security of
1567 Linux kernels running on their architecture (or
1570 config DEBUG_KOBJECT
1571 bool "kobject debugging"
1572 depends on DEBUG_KERNEL
1574 If you say Y here, some extra kobject debugging messages will be sent
1577 config DEBUG_KOBJECT_RELEASE
1578 bool "kobject release debugging"
1579 depends on DEBUG_OBJECTS_TIMERS
1581 kobjects are reference counted objects. This means that their
1582 last reference count put is not predictable, and the kobject can
1583 live on past the point at which a driver decides to drop its
1584 initial reference to the kobject gained on allocation. An
1585 example of this would be a struct device which has just been
1588 However, some buggy drivers assume that after such an operation,
1589 the memory backing the kobject can be immediately freed. This
1590 goes completely against the principles of a refcounted object.
1592 If you say Y here, the kernel will delay the release of kobjects
1593 on the last reference count to improve the visibility of this
1594 kind of kobject release bug.
1596 config HAVE_DEBUG_BUGVERBOSE
1599 menu "Debug kernel data structures"
1602 bool "Debug linked list manipulation"
1603 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1605 Enable this to turn on extended checks in the linked-list
1611 bool "Debug priority linked list manipulation"
1612 depends on DEBUG_KERNEL
1614 Enable this to turn on extended checks in the priority-ordered
1615 linked-list (plist) walking routines. This checks the entire
1616 list multiple times during each manipulation.
1621 bool "Debug SG table operations"
1622 depends on DEBUG_KERNEL
1624 Enable this to turn on checks on scatter-gather tables. This can
1625 help find problems with drivers that do not properly initialize
1630 config DEBUG_NOTIFIERS
1631 bool "Debug notifier call chains"
1632 depends on DEBUG_KERNEL
1634 Enable this to turn on sanity checking for notifier call chains.
1635 This is most useful for kernel developers to make sure that
1636 modules properly unregister themselves from notifier chains.
1637 This is a relatively cheap check but if you care about maximum
1640 config BUG_ON_DATA_CORRUPTION
1641 bool "Trigger a BUG when data corruption is detected"
1644 Select this option if the kernel should BUG when it encounters
1645 data corruption in kernel memory structures when they get checked
1650 config DEBUG_MAPLE_TREE
1651 bool "Debug maple trees"
1652 depends on DEBUG_KERNEL
1654 Enable maple tree debugging information and extra validations.
1660 config DEBUG_CREDENTIALS
1661 bool "Debug credential management"
1662 depends on DEBUG_KERNEL
1664 Enable this to turn on some debug checking for credential
1665 management. The additional code keeps track of the number of
1666 pointers from task_structs to any given cred struct, and checks to
1667 see that this number never exceeds the usage count of the cred
1670 Furthermore, if SELinux is enabled, this also checks that the
1671 security pointer in the cred struct is never seen to be invalid.
1675 source "kernel/rcu/Kconfig.debug"
1677 config DEBUG_WQ_FORCE_RR_CPU
1678 bool "Force round-robin CPU selection for unbound work items"
1679 depends on DEBUG_KERNEL
1682 Workqueue used to implicitly guarantee that work items queued
1683 without explicit CPU specified are put on the local CPU. This
1684 guarantee is no longer true and while local CPU is still
1685 preferred work items may be put on foreign CPUs. Kernel
1686 parameter "workqueue.debug_force_rr_cpu" is added to force
1687 round-robin CPU selection to flush out usages which depend on the
1688 now broken guarantee. This config option enables the debug
1689 feature by default. When enabled, memory and cache locality will
1692 config CPU_HOTPLUG_STATE_CONTROL
1693 bool "Enable CPU hotplug state control"
1694 depends on DEBUG_KERNEL
1695 depends on HOTPLUG_CPU
1698 Allows to write steps between "offline" and "online" to the CPUs
1699 sysfs target file so states can be stepped granular. This is a debug
1700 option for now as the hotplug machinery cannot be stopped and
1701 restarted at arbitrary points yet.
1703 Say N if your are unsure.
1706 bool "Latency measuring infrastructure"
1707 depends on DEBUG_KERNEL
1708 depends on STACKTRACE_SUPPORT
1710 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1716 Enable this option if you want to use the LatencyTOP tool
1717 to find out which userspace is blocking on what kernel operations.
1719 source "kernel/trace/Kconfig"
1721 config PROVIDE_OHCI1394_DMA_INIT
1722 bool "Remote debugging over FireWire early on boot"
1723 depends on PCI && X86
1725 If you want to debug problems which hang or crash the kernel early
1726 on boot and the crashing machine has a FireWire port, you can use
1727 this feature to remotely access the memory of the crashed machine
1728 over FireWire. This employs remote DMA as part of the OHCI1394
1729 specification which is now the standard for FireWire controllers.
1731 With remote DMA, you can monitor the printk buffer remotely using
1732 firescope and access all memory below 4GB using fireproxy from gdb.
1733 Even controlling a kernel debugger is possible using remote DMA.
1737 If ohci1394_dma=early is used as boot parameter, it will initialize
1738 all OHCI1394 controllers which are found in the PCI config space.
1740 As all changes to the FireWire bus such as enabling and disabling
1741 devices cause a bus reset and thereby disable remote DMA for all
1742 devices, be sure to have the cable plugged and FireWire enabled on
1743 the debugging host before booting the debug target for debugging.
1745 This code (~1k) is freed after boot. By then, the firewire stack
1746 in charge of the OHCI-1394 controllers should be used instead.
1748 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1750 source "samples/Kconfig"
1752 config ARCH_HAS_DEVMEM_IS_ALLOWED
1755 config STRICT_DEVMEM
1756 bool "Filter access to /dev/mem"
1757 depends on MMU && DEVMEM
1758 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1759 default y if PPC || X86 || ARM64
1761 If this option is disabled, you allow userspace (root) access to all
1762 of memory, including kernel and userspace memory. Accidental
1763 access to this is obviously disastrous, but specific access can
1764 be used by people debugging the kernel. Note that with PAT support
1765 enabled, even in this case there are restrictions on /dev/mem
1766 use due to the cache aliasing requirements.
1768 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1769 file only allows userspace access to PCI space and the BIOS code and
1770 data regions. This is sufficient for dosemu and X and all common
1775 config IO_STRICT_DEVMEM
1776 bool "Filter I/O access to /dev/mem"
1777 depends on STRICT_DEVMEM
1779 If this option is disabled, you allow userspace (root) access to all
1780 io-memory regardless of whether a driver is actively using that
1781 range. Accidental access to this is obviously disastrous, but
1782 specific access can be used by people debugging kernel drivers.
1784 If this option is switched on, the /dev/mem file only allows
1785 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1786 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1787 if the driver using a given range cannot be disabled.
1791 menu "$(SRCARCH) Debugging"
1793 source "arch/$(SRCARCH)/Kconfig.debug"
1797 menu "Kernel Testing and Coverage"
1799 source "lib/kunit/Kconfig"
1801 config NOTIFIER_ERROR_INJECTION
1802 tristate "Notifier error injection"
1803 depends on DEBUG_KERNEL
1806 This option provides the ability to inject artificial errors to
1807 specified notifier chain callbacks. It is useful to test the error
1808 handling of notifier call chain failures.
1812 config PM_NOTIFIER_ERROR_INJECT
1813 tristate "PM notifier error injection module"
1814 depends on PM && NOTIFIER_ERROR_INJECTION
1815 default m if PM_DEBUG
1817 This option provides the ability to inject artificial errors to
1818 PM notifier chain callbacks. It is controlled through debugfs
1819 interface /sys/kernel/debug/notifier-error-inject/pm
1821 If the notifier call chain should be failed with some events
1822 notified, write the error code to "actions/<notifier event>/error".
1824 Example: Inject PM suspend error (-12 = -ENOMEM)
1826 # cd /sys/kernel/debug/notifier-error-inject/pm/
1827 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1828 # echo mem > /sys/power/state
1829 bash: echo: write error: Cannot allocate memory
1831 To compile this code as a module, choose M here: the module will
1832 be called pm-notifier-error-inject.
1836 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1837 tristate "OF reconfig notifier error injection module"
1838 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1840 This option provides the ability to inject artificial errors to
1841 OF reconfig notifier chain callbacks. It is controlled
1842 through debugfs interface under
1843 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1845 If the notifier call chain should be failed with some events
1846 notified, write the error code to "actions/<notifier event>/error".
1848 To compile this code as a module, choose M here: the module will
1849 be called of-reconfig-notifier-error-inject.
1853 config NETDEV_NOTIFIER_ERROR_INJECT
1854 tristate "Netdev notifier error injection module"
1855 depends on NET && NOTIFIER_ERROR_INJECTION
1857 This option provides the ability to inject artificial errors to
1858 netdevice notifier chain callbacks. It is controlled through debugfs
1859 interface /sys/kernel/debug/notifier-error-inject/netdev
1861 If the notifier call chain should be failed with some events
1862 notified, write the error code to "actions/<notifier event>/error".
1864 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1866 # cd /sys/kernel/debug/notifier-error-inject/netdev
1867 # echo -22 > actions/NETDEV_CHANGEMTU/error
1868 # ip link set eth0 mtu 1024
1869 RTNETLINK answers: Invalid argument
1871 To compile this code as a module, choose M here: the module will
1872 be called netdev-notifier-error-inject.
1876 config FUNCTION_ERROR_INJECTION
1878 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1880 config FAULT_INJECTION
1881 bool "Fault-injection framework"
1882 depends on DEBUG_KERNEL
1884 Provide fault-injection framework.
1885 For more details, see Documentation/fault-injection/.
1888 bool "Fault-injection capability for kmalloc"
1889 depends on FAULT_INJECTION
1890 depends on SLAB || SLUB
1892 Provide fault-injection capability for kmalloc.
1894 config FAIL_PAGE_ALLOC
1895 bool "Fault-injection capability for alloc_pages()"
1896 depends on FAULT_INJECTION
1898 Provide fault-injection capability for alloc_pages().
1900 config FAULT_INJECTION_USERCOPY
1901 bool "Fault injection capability for usercopy functions"
1902 depends on FAULT_INJECTION
1904 Provides fault-injection capability to inject failures
1905 in usercopy functions (copy_from_user(), get_user(), ...).
1907 config FAIL_MAKE_REQUEST
1908 bool "Fault-injection capability for disk IO"
1909 depends on FAULT_INJECTION && BLOCK
1911 Provide fault-injection capability for disk IO.
1913 config FAIL_IO_TIMEOUT
1914 bool "Fault-injection capability for faking disk interrupts"
1915 depends on FAULT_INJECTION && BLOCK
1917 Provide fault-injection capability on end IO handling. This
1918 will make the block layer "forget" an interrupt as configured,
1919 thus exercising the error handling.
1921 Only works with drivers that use the generic timeout handling,
1922 for others it won't do anything.
1925 bool "Fault-injection capability for futexes"
1927 depends on FAULT_INJECTION && FUTEX
1929 Provide fault-injection capability for futexes.
1931 config FAULT_INJECTION_DEBUG_FS
1932 bool "Debugfs entries for fault-injection capabilities"
1933 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1935 Enable configuration of fault-injection capabilities via debugfs.
1937 config FAIL_FUNCTION
1938 bool "Fault-injection capability for functions"
1939 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1941 Provide function-based fault-injection capability.
1942 This will allow you to override a specific function with a return
1943 with given return value. As a result, function caller will see
1944 an error value and have to handle it. This is useful to test the
1945 error handling in various subsystems.
1947 config FAIL_MMC_REQUEST
1948 bool "Fault-injection capability for MMC IO"
1949 depends on FAULT_INJECTION_DEBUG_FS && MMC
1951 Provide fault-injection capability for MMC IO.
1952 This will make the mmc core return data errors. This is
1953 useful to test the error handling in the mmc block device
1954 and to test how the mmc host driver handles retries from
1958 bool "Fault-injection capability for SunRPC"
1959 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1961 Provide fault-injection capability for SunRPC and
1964 config FAULT_INJECTION_STACKTRACE_FILTER
1965 bool "stacktrace filter for fault-injection capabilities"
1966 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1969 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1971 Provide stacktrace filter for fault-injection capabilities
1973 config ARCH_HAS_KCOV
1976 An architecture should select this when it can successfully
1977 build and run with CONFIG_KCOV. This typically requires
1978 disabling instrumentation for some early boot code.
1980 config CC_HAS_SANCOV_TRACE_PC
1981 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1985 bool "Code coverage for fuzzing"
1986 depends on ARCH_HAS_KCOV
1987 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1988 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
1989 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
1991 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1992 select OBJTOOL if HAVE_NOINSTR_HACK
1994 KCOV exposes kernel code coverage information in a form suitable
1995 for coverage-guided fuzzing (randomized testing).
1997 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1998 different machines and across reboots. If you need stable PC values,
1999 disable RANDOMIZE_BASE.
2001 For more details, see Documentation/dev-tools/kcov.rst.
2003 config KCOV_ENABLE_COMPARISONS
2004 bool "Enable comparison operands collection by KCOV"
2006 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2008 KCOV also exposes operands of every comparison in the instrumented
2009 code along with operand sizes and PCs of the comparison instructions.
2010 These operands can be used by fuzzing engines to improve the quality
2011 of fuzzing coverage.
2013 config KCOV_INSTRUMENT_ALL
2014 bool "Instrument all code by default"
2018 If you are doing generic system call fuzzing (like e.g. syzkaller),
2019 then you will want to instrument the whole kernel and you should
2020 say y here. If you are doing more targeted fuzzing (like e.g.
2021 filesystem fuzzing with AFL) then you will want to enable coverage
2022 for more specific subsets of files, and should say n here.
2024 config KCOV_IRQ_AREA_SIZE
2025 hex "Size of interrupt coverage collection area in words"
2029 KCOV uses preallocated per-cpu areas to collect coverage from
2030 soft interrupts. This specifies the size of those areas in the
2031 number of unsigned long words.
2033 menuconfig RUNTIME_TESTING_MENU
2034 bool "Runtime Testing"
2037 if RUNTIME_TESTING_MENU
2040 tristate "Linux Kernel Dump Test Tool Module"
2043 This module enables testing of the different dumping mechanisms by
2044 inducing system failures at predefined crash points.
2045 If you don't need it: say N
2046 Choose M here to compile this code as a module. The module will be
2049 Documentation on how to use the module can be found in
2050 Documentation/fault-injection/provoke-crashes.rst
2052 config CPUMASK_KUNIT_TEST
2053 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2055 default KUNIT_ALL_TESTS
2057 Enable to turn on cpumask tests, running at boot or module load time.
2059 For more information on KUnit and unit tests in general, please refer
2060 to the KUnit documentation in Documentation/dev-tools/kunit/.
2064 config TEST_LIST_SORT
2065 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2067 default KUNIT_ALL_TESTS
2069 Enable this to turn on 'list_sort()' function test. This test is
2070 executed only once during system boot (so affects only boot time),
2071 or at module load time.
2075 config TEST_MIN_HEAP
2076 tristate "Min heap test"
2077 depends on DEBUG_KERNEL || m
2079 Enable this to turn on min heap function tests. This test is
2080 executed only once during system boot (so affects only boot time),
2081 or at module load time.
2086 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2088 default KUNIT_ALL_TESTS
2090 This option enables the self-test function of 'sort()' at boot,
2091 or at module load time.
2096 tristate "64bit/32bit division and modulo test"
2097 depends on DEBUG_KERNEL || m
2099 Enable this to turn on 'do_div()' function test. This test is
2100 executed only once during system boot (so affects only boot time),
2101 or at module load time.
2105 config KPROBES_SANITY_TEST
2106 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2107 depends on DEBUG_KERNEL
2110 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2111 default KUNIT_ALL_TESTS
2113 This option provides for testing basic kprobes functionality on
2114 boot. Samples of kprobe and kretprobe are inserted and
2115 verified for functionality.
2117 Say N if you are unsure.
2119 config FPROBE_SANITY_TEST
2120 bool "Self test for fprobe"
2121 depends on DEBUG_KERNEL
2125 This option will enable testing the fprobe when the system boot.
2126 A series of tests are made to verify that the fprobe is functioning
2129 Say N if you are unsure.
2131 config BACKTRACE_SELF_TEST
2132 tristate "Self test for the backtrace code"
2133 depends on DEBUG_KERNEL
2135 This option provides a kernel module that can be used to test
2136 the kernel stack backtrace code. This option is not useful
2137 for distributions or general kernels, but only for kernel
2138 developers working on architecture code.
2140 Note that if you want to also test saved backtraces, you will
2141 have to enable STACKTRACE as well.
2143 Say N if you are unsure.
2145 config TEST_REF_TRACKER
2146 tristate "Self test for reference tracker"
2147 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2150 This option provides a kernel module performing tests
2151 using reference tracker infrastructure.
2153 Say N if you are unsure.
2156 tristate "Red-Black tree test"
2157 depends on DEBUG_KERNEL
2159 A benchmark measuring the performance of the rbtree library.
2160 Also includes rbtree invariant checks.
2162 config REED_SOLOMON_TEST
2163 tristate "Reed-Solomon library test"
2164 depends on DEBUG_KERNEL || m
2166 select REED_SOLOMON_ENC16
2167 select REED_SOLOMON_DEC16
2169 This option enables the self-test function of rslib at boot,
2170 or at module load time.
2174 config INTERVAL_TREE_TEST
2175 tristate "Interval tree test"
2176 depends on DEBUG_KERNEL
2177 select INTERVAL_TREE
2179 A benchmark measuring the performance of the interval tree library
2182 tristate "Per cpu operations test"
2183 depends on m && DEBUG_KERNEL
2185 Enable this option to build test module which validates per-cpu
2190 config ATOMIC64_SELFTEST
2191 tristate "Perform an atomic64_t self-test"
2193 Enable this option to test the atomic64_t functions at boot or
2194 at module load time.
2198 config ASYNC_RAID6_TEST
2199 tristate "Self test for hardware accelerated raid6 recovery"
2200 depends on ASYNC_RAID6_RECOV
2203 This is a one-shot self test that permutes through the
2204 recovery of all the possible two disk failure scenarios for a
2205 N-disk array. Recovery is performed with the asynchronous
2206 raid6 recovery routines, and will optionally use an offload
2207 engine if one is available.
2212 tristate "Test functions located in the hexdump module at runtime"
2214 config STRING_SELFTEST
2215 tristate "Test string functions at runtime"
2217 config TEST_STRING_HELPERS
2218 tristate "Test functions located in the string_helpers module at runtime"
2221 tristate "Test strscpy*() family of functions at runtime"
2224 tristate "Test kstrto*() family of functions at runtime"
2227 tristate "Test printf() family of functions at runtime"
2230 tristate "Test scanf() family of functions at runtime"
2233 tristate "Test bitmap_*() family of functions at runtime"
2235 Enable this option to test the bitmap functions at boot.
2240 tristate "Test functions located in the uuid module at runtime"
2243 tristate "Test the XArray code at runtime"
2245 config TEST_MAPLE_TREE
2246 select DEBUG_MAPLE_TREE
2247 tristate "Test the Maple Tree code at runtime"
2249 config TEST_RHASHTABLE
2250 tristate "Perform selftest on resizable hash table"
2252 Enable this option to test the rhashtable functions at boot.
2257 tristate "Perform selftest on siphash functions"
2259 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2260 functions on boot (or module load).
2262 This is intended to help people writing architecture-specific
2263 optimized versions. If unsure, say N.
2266 tristate "Perform selftest on IDA functions"
2269 tristate "Perform selftest on priority array manager"
2272 Enable this option to test priority array manager on boot
2277 config TEST_IRQ_TIMINGS
2278 bool "IRQ timings selftest"
2279 depends on IRQ_TIMINGS
2281 Enable this option to test the irq timings code on boot.
2286 tristate "Test module loading with 'hello world' module"
2289 This builds the "test_module" module that emits "Hello, world"
2290 on printk when loaded. It is designed to be used for basic
2291 evaluation of the module loading subsystem (for example when
2292 validating module verification). It lacks any extra dependencies,
2293 and will not normally be loaded by the system unless explicitly
2299 tristate "Test module for compilation of bitops operations"
2302 This builds the "test_bitops" module that is much like the
2303 TEST_LKM module except that it does a basic exercise of the
2304 set/clear_bit macros and get_count_order/long to make sure there are
2305 no compiler warnings from C=1 sparse checker or -Wextra
2306 compilations. It has no dependencies and doesn't run or load unless
2307 explicitly requested by name. for example: modprobe test_bitops.
2312 tristate "Test module for stress/performance analysis of vmalloc allocator"
2317 This builds the "test_vmalloc" module that should be used for
2318 stress and performance analysis. So, any new change for vmalloc
2319 subsystem can be evaluated from performance and stability point
2324 config TEST_USER_COPY
2325 tristate "Test user/kernel boundary protections"
2328 This builds the "test_user_copy" module that runs sanity checks
2329 on the copy_to/from_user infrastructure, making sure basic
2330 user/kernel boundary testing is working. If it fails to load,
2331 a regression has been detected in the user/kernel memory boundary
2337 tristate "Test BPF filter functionality"
2340 This builds the "test_bpf" module that runs various test vectors
2341 against the BPF interpreter or BPF JIT compiler depending on the
2342 current setting. This is in particular useful for BPF JIT compiler
2343 development, but also to run regression tests against changes in
2344 the interpreter code. It also enables test stubs for eBPF maps and
2345 verifier used by user space verifier testsuite.
2349 config TEST_BLACKHOLE_DEV
2350 tristate "Test blackhole netdev functionality"
2353 This builds the "test_blackhole_dev" module that validates the
2354 data path through this blackhole netdev.
2358 config FIND_BIT_BENCHMARK
2359 tristate "Test find_bit functions"
2361 This builds the "test_find_bit" module that measure find_*_bit()
2362 functions performance.
2366 config TEST_FIRMWARE
2367 tristate "Test firmware loading via userspace interface"
2368 depends on FW_LOADER
2370 This builds the "test_firmware" module that creates a userspace
2371 interface for testing firmware loading. This can be used to
2372 control the triggering of firmware loading without needing an
2373 actual firmware-using device. The contents can be rechecked by
2379 tristate "sysctl test driver"
2380 depends on PROC_SYSCTL
2382 This builds the "test_sysctl" module. This driver enables to test the
2383 proc sysctl interfaces available to drivers safely without affecting
2384 production knobs which might alter system functionality.
2388 config BITFIELD_KUNIT
2389 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2391 default KUNIT_ALL_TESTS
2393 Enable this option to test the bitfield functions at boot.
2395 KUnit tests run during boot and output the results to the debug log
2396 in TAP format (http://testanything.org/). Only useful for kernel devs
2397 running the KUnit test harness, and not intended for inclusion into a
2400 For more information on KUnit and unit tests in general please refer
2401 to the KUnit documentation in Documentation/dev-tools/kunit/.
2405 config HASH_KUNIT_TEST
2406 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2408 default KUNIT_ALL_TESTS
2410 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2411 integer (<linux/hash.h>) hash functions on boot.
2413 KUnit tests run during boot and output the results to the debug log
2414 in TAP format (https://testanything.org/). Only useful for kernel devs
2415 running the KUnit test harness, and not intended for inclusion into a
2418 For more information on KUnit and unit tests in general please refer
2419 to the KUnit documentation in Documentation/dev-tools/kunit/.
2421 This is intended to help people writing architecture-specific
2422 optimized versions. If unsure, say N.
2424 config RESOURCE_KUNIT_TEST
2425 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2427 default KUNIT_ALL_TESTS
2429 This builds the resource API unit test.
2430 Tests the logic of API provided by resource.c and ioport.h.
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 SYSCTL_KUNIT_TEST
2437 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2439 default KUNIT_ALL_TESTS
2441 This builds the proc sysctl unit test, which runs on boot.
2442 Tests the API contract and implementation correctness of sysctl.
2443 For more information on KUnit and unit tests in general please refer
2444 to the KUnit documentation in Documentation/dev-tools/kunit/.
2448 config LIST_KUNIT_TEST
2449 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2451 default KUNIT_ALL_TESTS
2453 This builds the linked list KUnit test suite.
2454 It tests that the API and basic functionality of the list_head type
2455 and associated macros.
2457 KUnit tests run during boot and output the results to the debug log
2458 in TAP format (https://testanything.org/). Only useful for kernel devs
2459 running the KUnit test harness, and not intended for inclusion into a
2462 For more information on KUnit and unit tests in general please refer
2463 to the KUnit documentation in Documentation/dev-tools/kunit/.
2467 config LINEAR_RANGES_TEST
2468 tristate "KUnit test for linear_ranges"
2470 select LINEAR_RANGES
2472 This builds the linear_ranges unit test, which runs on boot.
2473 Tests the linear_ranges logic correctness.
2474 For more information on KUnit and unit tests in general please refer
2475 to the KUnit documentation in Documentation/dev-tools/kunit/.
2479 config CMDLINE_KUNIT_TEST
2480 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2482 default KUNIT_ALL_TESTS
2484 This builds the cmdline API unit test.
2485 Tests the logic of API provided by cmdline.c.
2486 For more information on KUnit and unit tests in general please refer
2487 to the KUnit documentation in Documentation/dev-tools/kunit/.
2492 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2494 default KUNIT_ALL_TESTS
2496 This builds the bits unit test.
2497 Tests the logic of macros defined in bits.h.
2498 For more information on KUnit and unit tests in general please refer
2499 to the KUnit documentation in Documentation/dev-tools/kunit/.
2503 config SLUB_KUNIT_TEST
2504 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2505 depends on SLUB_DEBUG && KUNIT
2506 default KUNIT_ALL_TESTS
2508 This builds SLUB allocator unit test.
2509 Tests SLUB cache debugging functionality.
2510 For more information on KUnit and unit tests in general please refer
2511 to the KUnit documentation in Documentation/dev-tools/kunit/.
2515 config RATIONAL_KUNIT_TEST
2516 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2517 depends on KUNIT && RATIONAL
2518 default KUNIT_ALL_TESTS
2520 This builds the rational math unit test.
2521 For more information on KUnit and unit tests in general please refer
2522 to the KUnit documentation in Documentation/dev-tools/kunit/.
2526 config MEMCPY_KUNIT_TEST
2527 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2529 default KUNIT_ALL_TESTS
2531 Builds unit tests for memcpy(), memmove(), and memset() functions.
2532 For more information on KUnit and unit tests in general please refer
2533 to the KUnit documentation in Documentation/dev-tools/kunit/.
2537 config IS_SIGNED_TYPE_KUNIT_TEST
2538 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2540 default KUNIT_ALL_TESTS
2542 Builds unit tests for the is_signed_type() macro.
2544 For more information on KUnit and unit tests in general please refer
2545 to the KUnit documentation in Documentation/dev-tools/kunit/.
2549 config OVERFLOW_KUNIT_TEST
2550 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2552 default KUNIT_ALL_TESTS
2554 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2557 For more information on KUnit and unit tests in general please refer
2558 to the KUnit documentation in Documentation/dev-tools/kunit/.
2562 config STACKINIT_KUNIT_TEST
2563 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2565 default KUNIT_ALL_TESTS
2567 Test if the kernel is zero-initializing stack variables and
2568 padding. Coverage is controlled by compiler flags,
2569 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2570 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2571 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2573 config FORTIFY_KUNIT_TEST
2574 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2575 depends on KUNIT && FORTIFY_SOURCE
2576 default KUNIT_ALL_TESTS
2578 Builds unit tests for checking internals of FORTIFY_SOURCE as used
2579 by the str*() and mem*() family of functions. For testing runtime
2580 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2582 config HW_BREAKPOINT_KUNIT_TEST
2583 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2584 depends on HAVE_HW_BREAKPOINT
2586 default KUNIT_ALL_TESTS
2588 Tests for hw_breakpoint constraints accounting.
2593 tristate "udelay test driver"
2595 This builds the "udelay_test" module that helps to make sure
2596 that udelay() is working properly.
2600 config TEST_STATIC_KEYS
2601 tristate "Test static keys"
2604 Test the static key interfaces.
2608 config TEST_DYNAMIC_DEBUG
2609 tristate "Test DYNAMIC_DEBUG"
2610 depends on DYNAMIC_DEBUG
2612 This module registers a tracer callback to count enabled
2613 pr_debugs in a 'do_debugging' function, then alters their
2614 enablements, calls the function, and compares counts.
2619 tristate "kmod stress tester"
2621 depends on NETDEVICES && NET_CORE && INET # for TUN
2623 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2629 Test the kernel's module loading mechanism: kmod. kmod implements
2630 support to load modules using the Linux kernel's usermode helper.
2631 This test provides a series of tests against kmod.
2633 Although technically you can either build test_kmod as a module or
2634 into the kernel we disallow building it into the kernel since
2635 it stress tests request_module() and this will very likely cause
2636 some issues by taking over precious threads available from other
2637 module load requests, ultimately this could be fatal.
2641 tools/testing/selftests/kmod/kmod.sh --help
2645 config TEST_DEBUG_VIRTUAL
2646 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2647 depends on DEBUG_VIRTUAL
2649 Test the kernel's ability to detect incorrect calls to
2650 virt_to_phys() done against the non-linear part of the
2651 kernel's virtual address map.
2655 config TEST_MEMCAT_P
2656 tristate "Test memcat_p() helper function"
2658 Test the memcat_p() helper for correctly merging two
2659 pointer arrays together.
2663 config TEST_LIVEPATCH
2664 tristate "Test livepatching"
2666 depends on DYNAMIC_DEBUG
2667 depends on LIVEPATCH
2670 Test kernel livepatching features for correctness. The tests will
2671 load test modules that will be livepatched in various scenarios.
2673 To run all the livepatching tests:
2675 make -C tools/testing/selftests TARGETS=livepatch run_tests
2677 Alternatively, individual tests may be invoked:
2679 tools/testing/selftests/livepatch/test-callbacks.sh
2680 tools/testing/selftests/livepatch/test-livepatch.sh
2681 tools/testing/selftests/livepatch/test-shadow-vars.sh
2686 tristate "Perform selftest on object aggreration manager"
2690 Enable this option to test object aggregation manager on boot
2694 tristate "Test heap/page initialization"
2696 Test if the kernel is zero-initializing heap and page allocations.
2697 This can be useful to test init_on_alloc and init_on_free features.
2702 tristate "Test HMM (Heterogeneous Memory Management)"
2703 depends on TRANSPARENT_HUGEPAGE
2704 depends on DEVICE_PRIVATE
2708 This is a pseudo device driver solely for testing HMM.
2709 Say M here if you want to build the HMM test module.
2710 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2714 config TEST_FREE_PAGES
2715 tristate "Test freeing pages"
2717 Test that a memory leak does not occur due to a race between
2718 freeing a block of pages and a speculative page reference.
2719 Loading this module is safe if your kernel has the bug fixed.
2720 If the bug is not fixed, it will leak gigabytes of memory and
2721 probably OOM your system.
2724 tristate "Test floating point operations in kernel space"
2725 depends on X86 && !KCOV_INSTRUMENT_ALL
2727 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2728 which will trigger a sequence of floating point operations. This is used
2729 for self-testing floating point control register setting in
2734 config TEST_CLOCKSOURCE_WATCHDOG
2735 tristate "Test clocksource watchdog in kernel space"
2736 depends on CLOCKSOURCE_WATCHDOG
2738 Enable this option to create a kernel module that will trigger
2739 a test of the clocksource watchdog. This module may be loaded
2740 via modprobe or insmod in which case it will run upon being
2741 loaded, or it may be built in, in which case it will run
2746 endif # RUNTIME_TESTING_MENU
2748 config ARCH_USE_MEMTEST
2751 An architecture should select this when it uses early_memtest()
2752 during boot process.
2756 depends on ARCH_USE_MEMTEST
2758 This option adds a kernel parameter 'memtest', which allows memtest
2759 to be set and executed.
2760 memtest=0, mean disabled; -- default
2761 memtest=1, mean do 1 test pattern;
2763 memtest=17, mean do 17 test patterns.
2764 If you are unsure how to answer this question, answer N.
2768 config HYPERV_TESTING
2769 bool "Microsoft Hyper-V driver testing"
2771 depends on HYPERV && DEBUG_FS
2773 Select this option to enable Hyper-V vmbus testing.
2775 endmenu # "Kernel Testing and Coverage"
2779 config RUST_DEBUG_ASSERTIONS
2780 bool "Debug assertions"
2783 Enables rustc's `-Cdebug-assertions` codegen option.
2785 This flag lets you turn `cfg(debug_assertions)` conditional
2786 compilation on or off. This can be used to enable extra debugging
2787 code in development but not in production. For example, it controls
2788 the behavior of the standard library's `debug_assert!` macro.
2790 Note that this will apply to all Rust code, including `core`.
2794 config RUST_OVERFLOW_CHECKS
2795 bool "Overflow checks"
2799 Enables rustc's `-Coverflow-checks` codegen option.
2801 This flag allows you to control the behavior of runtime integer
2802 overflow. When overflow-checks are enabled, a Rust panic will occur
2805 Note that this will apply to all Rust code, including `core`.
2811 source "Documentation/Kconfig"
2813 endmenu # Kernel hacking
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