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 1280 if KASAN && !64BIT
403 default 1024 if !64BIT
404 default 2048 if 64BIT
406 Tell the compiler to warn at build time for stack frames larger than this.
407 Setting this too low will cause a lot of warnings.
408 Setting it to 0 disables the warning.
410 config STRIP_ASM_SYMS
411 bool "Strip assembler-generated symbols during link"
414 Strip internal assembler-generated symbols during a link (symbols
415 that look like '.Lxxx') so they don't pollute the output of
416 get_wchan() and suchlike.
419 bool "Generate readable assembler code"
420 depends on DEBUG_KERNEL
423 Disable some compiler optimizations that tend to generate human unreadable
424 assembler output. This may make the kernel slightly slower, but it helps
425 to keep kernel developers who have to stare a lot at assembler listings
428 config HEADERS_INSTALL
429 bool "Install uapi headers to usr/include"
432 This option will install uapi headers (headers exported to user-space)
433 into the usr/include directory for use during the kernel build.
434 This is unneeded for building the kernel itself, but needed for some
435 user-space program samples. It is also needed by some features such
436 as uapi header sanity checks.
438 config DEBUG_SECTION_MISMATCH
439 bool "Enable full Section mismatch analysis"
442 The section mismatch analysis checks if there are illegal
443 references from one section to another section.
444 During linktime or runtime, some sections are dropped;
445 any use of code/data previously in these sections would
446 most likely result in an oops.
447 In the code, functions and variables are annotated with
448 __init,, etc. (see the full list in include/linux/init.h),
449 which results in the code/data being placed in specific sections.
450 The section mismatch analysis is always performed after a full
451 kernel build, and enabling this option causes the following
452 additional step to occur:
453 - Add the option -fno-inline-functions-called-once to gcc commands.
454 When inlining a function annotated with __init in a non-init
455 function, we would lose the section information and thus
456 the analysis would not catch the illegal reference.
457 This option tells gcc to inline less (but it does result in
460 config SECTION_MISMATCH_WARN_ONLY
461 bool "Make section mismatch errors non-fatal"
464 If you say N here, the build process will fail if there are any
465 section mismatch, instead of just throwing warnings.
469 config DEBUG_FORCE_FUNCTION_ALIGN_64B
470 bool "Force all function address 64B aligned"
471 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC)
473 There are cases that a commit from one domain changes the function
474 address alignment of other domains, and cause magic performance
475 bump (regression or improvement). Enable this option will help to
476 verify if the bump is caused by function alignment changes, while
477 it will slightly increase the kernel size and affect icache usage.
479 It is mainly for debug and performance tuning use.
482 # Select this config option from the architecture Kconfig, if it
483 # is preferred to always offer frame pointers as a config
484 # option on the architecture (regardless of KERNEL_DEBUG):
486 config ARCH_WANT_FRAME_POINTERS
490 bool "Compile the kernel with frame pointers"
491 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
492 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
494 If you say Y here the resulting kernel image will be slightly
495 larger and slower, but it gives very useful debugging information
496 in case of kernel bugs. (precise oopses/stacktraces/warnings)
501 config STACK_VALIDATION
502 bool "Compile-time stack metadata validation"
503 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
507 Validate frame pointer rules at compile-time. This helps ensure that
508 runtime stack traces are more reliable.
510 For more information, see
511 tools/objtool/Documentation/objtool.txt.
513 config NOINSTR_VALIDATION
515 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
520 bool "Generate vmlinux.map file when linking"
523 Selecting this option will pass "-Map=vmlinux.map" to ld
524 when linking vmlinux. That file can be useful for verifying
525 and debugging magic section games, and for seeing which
526 pieces of code get eliminated with
527 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
529 config DEBUG_FORCE_WEAK_PER_CPU
530 bool "Force weak per-cpu definitions"
531 depends on DEBUG_KERNEL
533 s390 and alpha require percpu variables in modules to be
534 defined weak to work around addressing range issue which
535 puts the following two restrictions on percpu variable
538 1. percpu symbols must be unique whether static or not
539 2. percpu variables can't be defined inside a function
541 To ensure that generic code follows the above rules, this
542 option forces all percpu variables to be defined as weak.
544 endmenu # "Compiler options"
546 menu "Generic Kernel Debugging Instruments"
549 bool "Magic SysRq key"
552 If you say Y here, you will have some control over the system even
553 if the system crashes for example during kernel debugging (e.g., you
554 will be able to flush the buffer cache to disk, reboot the system
555 immediately or dump some status information). This is accomplished
556 by pressing various keys while holding SysRq (Alt+PrintScreen). It
557 also works on a serial console (on PC hardware at least), if you
558 send a BREAK and then within 5 seconds a command keypress. The
559 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
560 Don't say Y unless you really know what this hack does.
562 config MAGIC_SYSRQ_DEFAULT_ENABLE
563 hex "Enable magic SysRq key functions by default"
564 depends on MAGIC_SYSRQ
567 Specifies which SysRq key functions are enabled by default.
568 This may be set to 1 or 0 to enable or disable them all, or
569 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
571 config MAGIC_SYSRQ_SERIAL
572 bool "Enable magic SysRq key over serial"
573 depends on MAGIC_SYSRQ
576 Many embedded boards have a disconnected TTL level serial which can
577 generate some garbage that can lead to spurious false sysrq detects.
578 This option allows you to decide whether you want to enable the
581 config MAGIC_SYSRQ_SERIAL_SEQUENCE
582 string "Char sequence that enables magic SysRq over serial"
583 depends on MAGIC_SYSRQ_SERIAL
586 Specifies a sequence of characters that can follow BREAK to enable
587 SysRq on a serial console.
589 If unsure, leave an empty string and the option will not be enabled.
592 bool "Debug Filesystem"
594 debugfs is a virtual file system that kernel developers use to put
595 debugging files into. Enable this option to be able to read and
596 write to these files.
598 For detailed documentation on the debugfs API, see
599 Documentation/filesystems/.
604 prompt "Debugfs default access"
606 default DEBUG_FS_ALLOW_ALL
608 This selects the default access restrictions for debugfs.
609 It can be overridden with kernel command line option
610 debugfs=[on,no-mount,off]. The restrictions apply for API access
611 and filesystem registration.
613 config DEBUG_FS_ALLOW_ALL
616 No restrictions apply. Both API and filesystem registration
617 is on. This is the normal default operation.
619 config DEBUG_FS_DISALLOW_MOUNT
620 bool "Do not register debugfs as filesystem"
622 The API is open but filesystem is not loaded. Clients can still do
623 their work and read with debug tools that do not need
626 config DEBUG_FS_ALLOW_NONE
629 Access is off. Clients get -PERM when trying to create nodes in
630 debugfs tree and debugfs is not registered as a filesystem.
631 Client can then back-off or continue without debugfs access.
635 source "lib/Kconfig.kgdb"
636 source "lib/Kconfig.ubsan"
637 source "lib/Kconfig.kcsan"
641 menu "Networking Debugging"
643 source "net/Kconfig.debug"
645 endmenu # "Networking Debugging"
647 menu "Memory Debugging"
649 source "mm/Kconfig.debug"
652 bool "Debug object operations"
653 depends on DEBUG_KERNEL
655 If you say Y here, additional code will be inserted into the
656 kernel to track the life time of various objects and validate
657 the operations on those objects.
659 config DEBUG_OBJECTS_SELFTEST
660 bool "Debug objects selftest"
661 depends on DEBUG_OBJECTS
663 This enables the selftest of the object debug code.
665 config DEBUG_OBJECTS_FREE
666 bool "Debug objects in freed memory"
667 depends on DEBUG_OBJECTS
669 This enables checks whether a k/v free operation frees an area
670 which contains an object which has not been deactivated
671 properly. This can make kmalloc/kfree-intensive workloads
674 config DEBUG_OBJECTS_TIMERS
675 bool "Debug timer objects"
676 depends on DEBUG_OBJECTS
678 If you say Y here, additional code will be inserted into the
679 timer routines to track the life time of timer objects and
680 validate the timer operations.
682 config DEBUG_OBJECTS_WORK
683 bool "Debug work objects"
684 depends on DEBUG_OBJECTS
686 If you say Y here, additional code will be inserted into the
687 work queue routines to track the life time of work objects and
688 validate the work operations.
690 config DEBUG_OBJECTS_RCU_HEAD
691 bool "Debug RCU callbacks objects"
692 depends on DEBUG_OBJECTS
694 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
696 config DEBUG_OBJECTS_PERCPU_COUNTER
697 bool "Debug percpu counter objects"
698 depends on DEBUG_OBJECTS
700 If you say Y here, additional code will be inserted into the
701 percpu counter routines to track the life time of percpu counter
702 objects and validate the percpu counter operations.
704 config DEBUG_OBJECTS_ENABLE_DEFAULT
705 int "debug_objects bootup default value (0-1)"
708 depends on DEBUG_OBJECTS
710 Debug objects boot parameter default value
712 config SHRINKER_DEBUG
713 bool "Enable shrinker debugging support"
716 Say Y to enable the shrinker debugfs interface which provides
717 visibility into the kernel memory shrinkers subsystem.
718 Disable it to avoid an extra memory footprint.
720 config HAVE_DEBUG_KMEMLEAK
723 config DEBUG_KMEMLEAK
724 bool "Kernel memory leak detector"
725 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
727 select STACKTRACE if STACKTRACE_SUPPORT
731 Say Y here if you want to enable the memory leak
732 detector. The memory allocation/freeing is traced in a way
733 similar to the Boehm's conservative garbage collector, the
734 difference being that the orphan objects are not freed but
735 only shown in /sys/kernel/debug/kmemleak. Enabling this
736 feature will introduce an overhead to memory
737 allocations. See Documentation/dev-tools/kmemleak.rst for more
740 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
741 of finding leaks due to the slab objects poisoning.
743 In order to access the kmemleak file, debugfs needs to be
744 mounted (usually at /sys/kernel/debug).
746 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
747 int "Kmemleak memory pool size"
748 depends on DEBUG_KMEMLEAK
752 Kmemleak must track all the memory allocations to avoid
753 reporting false positives. Since memory may be allocated or
754 freed before kmemleak is fully initialised, use a static pool
755 of metadata objects to track such callbacks. After kmemleak is
756 fully initialised, this memory pool acts as an emergency one
757 if slab allocations fail.
759 config DEBUG_KMEMLEAK_TEST
760 tristate "Simple test for the kernel memory leak detector"
761 depends on DEBUG_KMEMLEAK && m
763 This option enables a module that explicitly leaks memory.
767 config DEBUG_KMEMLEAK_DEFAULT_OFF
768 bool "Default kmemleak to off"
769 depends on DEBUG_KMEMLEAK
771 Say Y here to disable kmemleak by default. It can then be enabled
772 on the command line via kmemleak=on.
774 config DEBUG_KMEMLEAK_AUTO_SCAN
775 bool "Enable kmemleak auto scan thread on boot up"
777 depends on DEBUG_KMEMLEAK
779 Depending on the cpu, kmemleak scan may be cpu intensive and can
780 stall user tasks at times. This option enables/disables automatic
781 kmemleak scan at boot up.
783 Say N here to disable kmemleak auto scan thread to stop automatic
784 scanning. Disabling this option disables automatic reporting of
789 config DEBUG_STACK_USAGE
790 bool "Stack utilization instrumentation"
791 depends on DEBUG_KERNEL && !IA64
793 Enables the display of the minimum amount of free stack which each
794 task has ever had available in the sysrq-T and sysrq-P debug output.
796 This option will slow down process creation somewhat.
798 config SCHED_STACK_END_CHECK
799 bool "Detect stack corruption on calls to schedule()"
800 depends on DEBUG_KERNEL
803 This option checks for a stack overrun on calls to schedule().
804 If the stack end location is found to be over written always panic as
805 the content of the corrupted region can no longer be trusted.
806 This is to ensure no erroneous behaviour occurs which could result in
807 data corruption or a sporadic crash at a later stage once the region
808 is examined. The runtime overhead introduced is minimal.
810 config ARCH_HAS_DEBUG_VM_PGTABLE
813 An architecture should select this when it can successfully
814 build and run DEBUG_VM_PGTABLE.
816 config DEBUG_VM_IRQSOFF
817 def_bool DEBUG_VM && !PREEMPT_RT
821 depends on DEBUG_KERNEL
823 Enable this to turn on extended checks in the virtual-memory system
824 that may impact performance.
828 config DEBUG_VM_MAPLE_TREE
829 bool "Debug VM maple trees"
831 select DEBUG_MAPLE_TREE
833 Enable VM maple tree debugging information and extra validations.
838 bool "Debug VM red-black trees"
841 Enable VM red-black tree debugging information and extra validations.
845 config DEBUG_VM_PGFLAGS
846 bool "Debug page-flags operations"
849 Enables extra validation on page flags operations.
853 config DEBUG_VM_PGTABLE
854 bool "Debug arch page table for semantics compliance"
856 depends on ARCH_HAS_DEBUG_VM_PGTABLE
857 default y if DEBUG_VM
859 This option provides a debug method which can be used to test
860 architecture page table helper functions on various platforms in
861 verifying if they comply with expected generic MM semantics. This
862 will help architecture code in making sure that any changes or
863 new additions of these helpers still conform to expected
864 semantics of the generic MM. Platforms will have to opt in for
865 this through ARCH_HAS_DEBUG_VM_PGTABLE.
869 config ARCH_HAS_DEBUG_VIRTUAL
873 bool "Debug VM translations"
874 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
876 Enable some costly sanity checks in virtual to page code. This can
877 catch mistakes with virt_to_page() and friends.
881 config DEBUG_NOMMU_REGIONS
882 bool "Debug the global anon/private NOMMU mapping region tree"
883 depends on DEBUG_KERNEL && !MMU
885 This option causes the global tree of anonymous and private mapping
886 regions to be regularly checked for invalid topology.
888 config DEBUG_MEMORY_INIT
889 bool "Debug memory initialisation" if EXPERT
892 Enable this for additional checks during memory initialisation.
893 The sanity checks verify aspects of the VM such as the memory model
894 and other information provided by the architecture. Verbose
895 information will be printed at KERN_DEBUG loglevel depending
896 on the mminit_loglevel= command-line option.
900 config MEMORY_NOTIFIER_ERROR_INJECT
901 tristate "Memory hotplug notifier error injection module"
902 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
904 This option provides the ability to inject artificial errors to
905 memory hotplug notifier chain callbacks. It is controlled through
906 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
908 If the notifier call chain should be failed with some events
909 notified, write the error code to "actions/<notifier event>/error".
911 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
913 # cd /sys/kernel/debug/notifier-error-inject/memory
914 # echo -12 > actions/MEM_GOING_OFFLINE/error
915 # echo offline > /sys/devices/system/memory/memoryXXX/state
916 bash: echo: write error: Cannot allocate memory
918 To compile this code as a module, choose M here: the module will
919 be called memory-notifier-error-inject.
923 config DEBUG_PER_CPU_MAPS
924 bool "Debug access to per_cpu maps"
925 depends on DEBUG_KERNEL
928 Say Y to verify that the per_cpu map being accessed has
929 been set up. This adds a fair amount of code to kernel memory
930 and decreases performance.
934 config DEBUG_KMAP_LOCAL
935 bool "Debug kmap_local temporary mappings"
936 depends on DEBUG_KERNEL && KMAP_LOCAL
938 This option enables additional error checking for the kmap_local
939 infrastructure. Disable for production use.
941 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
944 config DEBUG_KMAP_LOCAL_FORCE_MAP
945 bool "Enforce kmap_local temporary mappings"
946 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
948 select DEBUG_KMAP_LOCAL
950 This option enforces temporary mappings through the kmap_local
951 mechanism for non-highmem pages and on non-highmem systems.
952 Disable this for production systems!
955 bool "Highmem debugging"
956 depends on DEBUG_KERNEL && HIGHMEM
957 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
958 select DEBUG_KMAP_LOCAL
960 This option enables additional error checking for high memory
961 systems. Disable for production systems.
963 config HAVE_DEBUG_STACKOVERFLOW
966 config DEBUG_STACKOVERFLOW
967 bool "Check for stack overflows"
968 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
970 Say Y here if you want to check for overflows of kernel, IRQ
971 and exception stacks (if your architecture uses them). This
972 option will show detailed messages if free stack space drops
973 below a certain limit.
975 These kinds of bugs usually occur when call-chains in the
976 kernel get too deep, especially when interrupts are
979 Use this in cases where you see apparently random memory
980 corruption, especially if it appears in 'struct thread_info'
982 If in doubt, say "N".
984 source "lib/Kconfig.kasan"
985 source "lib/Kconfig.kfence"
986 source "lib/Kconfig.kmsan"
988 endmenu # "Memory Debugging"
991 bool "Debug shared IRQ handlers"
992 depends on DEBUG_KERNEL
994 Enable this to generate a spurious interrupt just before a shared
995 interrupt handler is deregistered (generating one when registering
996 is currently disabled). Drivers need to handle this correctly. Some
997 don't and need to be caught.
999 menu "Debug Oops, Lockups and Hangs"
1001 config PANIC_ON_OOPS
1002 bool "Panic on Oops"
1004 Say Y here to enable the kernel to panic when it oopses. This
1005 has the same effect as setting oops=panic on the kernel command
1008 This feature is useful to ensure that the kernel does not do
1009 anything erroneous after an oops which could result in data
1010 corruption or other issues.
1014 config PANIC_ON_OOPS_VALUE
1017 default 0 if !PANIC_ON_OOPS
1018 default 1 if PANIC_ON_OOPS
1020 config PANIC_TIMEOUT
1024 Set the timeout value (in seconds) until a reboot occurs when
1025 the kernel panics. If n = 0, then we wait forever. A timeout
1026 value n > 0 will wait n seconds before rebooting, while a timeout
1027 value n < 0 will reboot immediately.
1029 config LOCKUP_DETECTOR
1032 config SOFTLOCKUP_DETECTOR
1033 bool "Detect Soft Lockups"
1034 depends on DEBUG_KERNEL && !S390
1035 select LOCKUP_DETECTOR
1037 Say Y here to enable the kernel to act as a watchdog to detect
1040 Softlockups are bugs that cause the kernel to loop in kernel
1041 mode for more than 20 seconds, without giving other tasks a
1042 chance to run. The current stack trace is displayed upon
1043 detection and the system will stay locked up.
1045 config BOOTPARAM_SOFTLOCKUP_PANIC
1046 bool "Panic (Reboot) On Soft Lockups"
1047 depends on SOFTLOCKUP_DETECTOR
1049 Say Y here to enable the kernel to panic on "soft lockups",
1050 which are bugs that cause the kernel to loop in kernel
1051 mode for more than 20 seconds (configurable using the watchdog_thresh
1052 sysctl), without giving other tasks a chance to run.
1054 The panic can be used in combination with panic_timeout,
1055 to cause the system to reboot automatically after a
1056 lockup has been detected. This feature is useful for
1057 high-availability systems that have uptime guarantees and
1058 where a lockup must be resolved ASAP.
1062 config HARDLOCKUP_DETECTOR_PERF
1064 select SOFTLOCKUP_DETECTOR
1067 # Enables a timestamp based low pass filter to compensate for perf based
1068 # hard lockup detection which runs too fast due to turbo modes.
1070 config HARDLOCKUP_CHECK_TIMESTAMP
1074 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1075 # lockup detector rather than the perf based detector.
1077 config HARDLOCKUP_DETECTOR
1078 bool "Detect Hard Lockups"
1079 depends on DEBUG_KERNEL && !S390
1080 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1081 select LOCKUP_DETECTOR
1082 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1084 Say Y here to enable the kernel to act as a watchdog to detect
1087 Hardlockups are bugs that cause the CPU to loop in kernel mode
1088 for more than 10 seconds, without letting other interrupts have a
1089 chance to run. The current stack trace is displayed upon detection
1090 and the system will stay locked up.
1092 config BOOTPARAM_HARDLOCKUP_PANIC
1093 bool "Panic (Reboot) On Hard Lockups"
1094 depends on HARDLOCKUP_DETECTOR
1096 Say Y here to enable the kernel to panic on "hard lockups",
1097 which are bugs that cause the kernel to loop in kernel
1098 mode with interrupts disabled for more than 10 seconds (configurable
1099 using the watchdog_thresh sysctl).
1103 config DETECT_HUNG_TASK
1104 bool "Detect Hung Tasks"
1105 depends on DEBUG_KERNEL
1106 default SOFTLOCKUP_DETECTOR
1108 Say Y here to enable the kernel to detect "hung tasks",
1109 which are bugs that cause the task to be stuck in
1110 uninterruptible "D" state indefinitely.
1112 When a hung task is detected, the kernel will print the
1113 current stack trace (which you should report), but the
1114 task will stay in uninterruptible state. If lockdep is
1115 enabled then all held locks will also be reported. This
1116 feature has negligible overhead.
1118 config DEFAULT_HUNG_TASK_TIMEOUT
1119 int "Default timeout for hung task detection (in seconds)"
1120 depends on DETECT_HUNG_TASK
1123 This option controls the default timeout (in seconds) used
1124 to determine when a task has become non-responsive and should
1127 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1128 sysctl or by writing a value to
1129 /proc/sys/kernel/hung_task_timeout_secs.
1131 A timeout of 0 disables the check. The default is two minutes.
1132 Keeping the default should be fine in most cases.
1134 config BOOTPARAM_HUNG_TASK_PANIC
1135 bool "Panic (Reboot) On Hung Tasks"
1136 depends on DETECT_HUNG_TASK
1138 Say Y here to enable the kernel to panic on "hung tasks",
1139 which are bugs that cause the kernel to leave a task stuck
1140 in uninterruptible "D" state.
1142 The panic can be used in combination with panic_timeout,
1143 to cause the system to reboot automatically after a
1144 hung task has been detected. This feature is useful for
1145 high-availability systems that have uptime guarantees and
1146 where a hung tasks must be resolved ASAP.
1151 bool "Detect Workqueue Stalls"
1152 depends on DEBUG_KERNEL
1154 Say Y here to enable stall detection on workqueues. If a
1155 worker pool doesn't make forward progress on a pending work
1156 item for over a given amount of time, 30s by default, a
1157 warning message is printed along with dump of workqueue
1158 state. This can be configured through kernel parameter
1159 "workqueue.watchdog_thresh" and its sysfs counterpart.
1162 tristate "Test module to generate lockups"
1165 This builds the "test_lockup" module that helps to make sure
1166 that watchdogs and lockup detectors are working properly.
1168 Depending on module parameters it could emulate soft or hard
1169 lockup, "hung task", or locking arbitrary lock for a long time.
1170 Also it could generate series of lockups with cooling-down periods.
1174 endmenu # "Debug lockups and hangs"
1176 menu "Scheduler Debugging"
1179 bool "Collect scheduler debugging info"
1180 depends on DEBUG_KERNEL && PROC_FS
1183 If you say Y here, the /proc/sched_debug file will be provided
1184 that can help debug the scheduler. The runtime overhead of this
1192 bool "Collect scheduler statistics"
1193 depends on DEBUG_KERNEL && PROC_FS
1196 If you say Y here, additional code will be inserted into the
1197 scheduler and related routines to collect statistics about
1198 scheduler behavior and provide them in /proc/schedstat. These
1199 stats may be useful for both tuning and debugging the scheduler
1200 If you aren't debugging the scheduler or trying to tune a specific
1201 application, you can say N to avoid the very slight overhead
1206 config DEBUG_TIMEKEEPING
1207 bool "Enable extra timekeeping sanity checking"
1209 This option will enable additional timekeeping sanity checks
1210 which may be helpful when diagnosing issues where timekeeping
1211 problems are suspected.
1213 This may include checks in the timekeeping hotpaths, so this
1214 option may have a (very small) performance impact to some
1219 config DEBUG_PREEMPT
1220 bool "Debug preemptible kernel"
1221 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1224 If you say Y here then the kernel will use a debug variant of the
1225 commonly used smp_processor_id() function and will print warnings
1226 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1227 will detect preemption count underflows.
1229 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1231 config LOCK_DEBUGGING_SUPPORT
1233 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1236 config PROVE_LOCKING
1237 bool "Lock debugging: prove locking correctness"
1238 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1240 select DEBUG_SPINLOCK
1241 select DEBUG_MUTEXES if !PREEMPT_RT
1242 select DEBUG_RT_MUTEXES if RT_MUTEXES
1244 select DEBUG_WW_MUTEX_SLOWPATH
1245 select DEBUG_LOCK_ALLOC
1246 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1247 select TRACE_IRQFLAGS
1250 This feature enables the kernel to prove that all locking
1251 that occurs in the kernel runtime is mathematically
1252 correct: that under no circumstance could an arbitrary (and
1253 not yet triggered) combination of observed locking
1254 sequences (on an arbitrary number of CPUs, running an
1255 arbitrary number of tasks and interrupt contexts) cause a
1258 In short, this feature enables the kernel to report locking
1259 related deadlocks before they actually occur.
1261 The proof does not depend on how hard and complex a
1262 deadlock scenario would be to trigger: how many
1263 participant CPUs, tasks and irq-contexts would be needed
1264 for it to trigger. The proof also does not depend on
1265 timing: if a race and a resulting deadlock is possible
1266 theoretically (no matter how unlikely the race scenario
1267 is), it will be proven so and will immediately be
1268 reported by the kernel (once the event is observed that
1269 makes the deadlock theoretically possible).
1271 If a deadlock is impossible (i.e. the locking rules, as
1272 observed by the kernel, are mathematically correct), the
1273 kernel reports nothing.
1275 NOTE: this feature can also be enabled for rwlocks, mutexes
1276 and rwsems - in which case all dependencies between these
1277 different locking variants are observed and mapped too, and
1278 the proof of observed correctness is also maintained for an
1279 arbitrary combination of these separate locking variants.
1281 For more details, see Documentation/locking/lockdep-design.rst.
1283 config PROVE_RAW_LOCK_NESTING
1284 bool "Enable raw_spinlock - spinlock nesting checks"
1285 depends on PROVE_LOCKING
1288 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1289 that the lock nesting rules for PREEMPT_RT enabled kernels are
1292 NOTE: There are known nesting problems. So if you enable this
1293 option expect lockdep splats until these problems have been fully
1294 addressed which is work in progress. This config switch allows to
1295 identify and analyze these problems. It will be removed and the
1296 check permanently enabled once the main issues have been fixed.
1298 If unsure, select N.
1301 bool "Lock usage statistics"
1302 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1304 select DEBUG_SPINLOCK
1305 select DEBUG_MUTEXES if !PREEMPT_RT
1306 select DEBUG_RT_MUTEXES if RT_MUTEXES
1307 select DEBUG_LOCK_ALLOC
1310 This feature enables tracking lock contention points
1312 For more details, see Documentation/locking/lockstat.rst
1314 This also enables lock events required by "perf lock",
1316 If you want to use "perf lock", you also need to turn on
1317 CONFIG_EVENT_TRACING.
1319 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1320 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1322 config DEBUG_RT_MUTEXES
1323 bool "RT Mutex debugging, deadlock detection"
1324 depends on DEBUG_KERNEL && RT_MUTEXES
1326 This allows rt mutex semantics violations and rt mutex related
1327 deadlocks (lockups) to be detected and reported automatically.
1329 config DEBUG_SPINLOCK
1330 bool "Spinlock and rw-lock debugging: basic checks"
1331 depends on DEBUG_KERNEL
1332 select UNINLINE_SPIN_UNLOCK
1334 Say Y here and build SMP to catch missing spinlock initialization
1335 and certain other kinds of spinlock errors commonly made. This is
1336 best used in conjunction with the NMI watchdog so that spinlock
1337 deadlocks are also debuggable.
1339 config DEBUG_MUTEXES
1340 bool "Mutex debugging: basic checks"
1341 depends on DEBUG_KERNEL && !PREEMPT_RT
1343 This feature allows mutex semantics violations to be detected and
1346 config DEBUG_WW_MUTEX_SLOWPATH
1347 bool "Wait/wound mutex debugging: Slowpath testing"
1348 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1349 select DEBUG_LOCK_ALLOC
1350 select DEBUG_SPINLOCK
1351 select DEBUG_MUTEXES if !PREEMPT_RT
1352 select DEBUG_RT_MUTEXES if PREEMPT_RT
1354 This feature enables slowpath testing for w/w mutex users by
1355 injecting additional -EDEADLK wound/backoff cases. Together with
1356 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1357 will test all possible w/w mutex interface abuse with the
1358 exception of simply not acquiring all the required locks.
1359 Note that this feature can introduce significant overhead, so
1360 it really should not be enabled in a production or distro kernel,
1361 even a debug kernel. If you are a driver writer, enable it. If
1362 you are a distro, do not.
1365 bool "RW Semaphore debugging: basic checks"
1366 depends on DEBUG_KERNEL
1368 This debugging feature allows mismatched rw semaphore locks
1369 and unlocks to be detected and reported.
1371 config DEBUG_LOCK_ALLOC
1372 bool "Lock debugging: detect incorrect freeing of live locks"
1373 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1374 select DEBUG_SPINLOCK
1375 select DEBUG_MUTEXES if !PREEMPT_RT
1376 select DEBUG_RT_MUTEXES if RT_MUTEXES
1379 This feature will check whether any held lock (spinlock, rwlock,
1380 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1381 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1382 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1383 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1384 held during task exit.
1388 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1393 config LOCKDEP_SMALL
1397 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1398 depends on LOCKDEP && !LOCKDEP_SMALL
1402 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1404 config LOCKDEP_CHAINS_BITS
1405 int "Bitsize for MAX_LOCKDEP_CHAINS"
1406 depends on LOCKDEP && !LOCKDEP_SMALL
1410 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1412 config LOCKDEP_STACK_TRACE_BITS
1413 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1414 depends on LOCKDEP && !LOCKDEP_SMALL
1418 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1420 config LOCKDEP_STACK_TRACE_HASH_BITS
1421 int "Bitsize for STACK_TRACE_HASH_SIZE"
1422 depends on LOCKDEP && !LOCKDEP_SMALL
1426 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1428 config LOCKDEP_CIRCULAR_QUEUE_BITS
1429 int "Bitsize for elements in circular_queue struct"
1434 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1436 config DEBUG_LOCKDEP
1437 bool "Lock dependency engine debugging"
1438 depends on DEBUG_KERNEL && LOCKDEP
1439 select DEBUG_IRQFLAGS
1441 If you say Y here, the lock dependency engine will do
1442 additional runtime checks to debug itself, at the price
1443 of more runtime overhead.
1445 config DEBUG_ATOMIC_SLEEP
1446 bool "Sleep inside atomic section checking"
1447 select PREEMPT_COUNT
1448 depends on DEBUG_KERNEL
1449 depends on !ARCH_NO_PREEMPT
1451 If you say Y here, various routines which may sleep will become very
1452 noisy if they are called inside atomic sections: when a spinlock is
1453 held, inside an rcu read side critical section, inside preempt disabled
1454 sections, inside an interrupt, etc...
1456 config DEBUG_LOCKING_API_SELFTESTS
1457 bool "Locking API boot-time self-tests"
1458 depends on DEBUG_KERNEL
1460 Say Y here if you want the kernel to run a short self-test during
1461 bootup. The self-test checks whether common types of locking bugs
1462 are detected by debugging mechanisms or not. (if you disable
1463 lock debugging then those bugs won't be detected of course.)
1464 The following locking APIs are covered: spinlocks, rwlocks,
1467 config LOCK_TORTURE_TEST
1468 tristate "torture tests for locking"
1469 depends on DEBUG_KERNEL
1472 This option provides a kernel module that runs torture tests
1473 on kernel locking primitives. The kernel module may be built
1474 after the fact on the running kernel to be tested, if desired.
1476 Say Y here if you want kernel locking-primitive torture tests
1477 to be built into the kernel.
1478 Say M if you want these torture tests to build as a module.
1479 Say N if you are unsure.
1481 config WW_MUTEX_SELFTEST
1482 tristate "Wait/wound mutex selftests"
1484 This option provides a kernel module that runs tests on the
1485 on the struct ww_mutex locking API.
1487 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1488 with this test harness.
1490 Say M if you want these self tests to build as a module.
1491 Say N if you are unsure.
1493 config SCF_TORTURE_TEST
1494 tristate "torture tests for smp_call_function*()"
1495 depends on DEBUG_KERNEL
1498 This option provides a kernel module that runs torture tests
1499 on the smp_call_function() family of primitives. The kernel
1500 module may be built after the fact on the running kernel to
1501 be tested, if desired.
1503 config CSD_LOCK_WAIT_DEBUG
1504 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1505 depends on DEBUG_KERNEL
1509 This option enables debug prints when CPUs are slow to respond
1510 to the smp_call_function*() IPI wrappers. These debug prints
1511 include the IPI handler function currently executing (if any)
1512 and relevant stack traces.
1514 endmenu # lock debugging
1516 config TRACE_IRQFLAGS
1517 depends on TRACE_IRQFLAGS_SUPPORT
1520 Enables hooks to interrupt enabling and disabling for
1521 either tracing or lock debugging.
1523 config TRACE_IRQFLAGS_NMI
1525 depends on TRACE_IRQFLAGS
1526 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1528 config DEBUG_IRQFLAGS
1529 bool "Debug IRQ flag manipulation"
1531 Enables checks for potentially unsafe enabling or disabling of
1532 interrupts, such as calling raw_local_irq_restore() when interrupts
1536 bool "Stack backtrace support"
1537 depends on STACKTRACE_SUPPORT
1539 This option causes the kernel to create a /proc/pid/stack for
1540 every process, showing its current stack trace.
1541 It is also used by various kernel debugging features that require
1542 stack trace generation.
1544 config WARN_ALL_UNSEEDED_RANDOM
1545 bool "Warn for all uses of unseeded randomness"
1548 Some parts of the kernel contain bugs relating to their use of
1549 cryptographically secure random numbers before it's actually possible
1550 to generate those numbers securely. This setting ensures that these
1551 flaws don't go unnoticed, by enabling a message, should this ever
1552 occur. This will allow people with obscure setups to know when things
1553 are going wrong, so that they might contact developers about fixing
1556 Unfortunately, on some models of some architectures getting
1557 a fully seeded CRNG is extremely difficult, and so this can
1558 result in dmesg getting spammed for a surprisingly long
1559 time. This is really bad from a security perspective, and
1560 so architecture maintainers really need to do what they can
1561 to get the CRNG seeded sooner after the system is booted.
1562 However, since users cannot do anything actionable to
1563 address this, by default this option is disabled.
1565 Say Y here if you want to receive warnings for all uses of
1566 unseeded randomness. This will be of use primarily for
1567 those developers interested in improving the security of
1568 Linux kernels running on their architecture (or
1571 config DEBUG_KOBJECT
1572 bool "kobject debugging"
1573 depends on DEBUG_KERNEL
1575 If you say Y here, some extra kobject debugging messages will be sent
1578 config DEBUG_KOBJECT_RELEASE
1579 bool "kobject release debugging"
1580 depends on DEBUG_OBJECTS_TIMERS
1582 kobjects are reference counted objects. This means that their
1583 last reference count put is not predictable, and the kobject can
1584 live on past the point at which a driver decides to drop its
1585 initial reference to the kobject gained on allocation. An
1586 example of this would be a struct device which has just been
1589 However, some buggy drivers assume that after such an operation,
1590 the memory backing the kobject can be immediately freed. This
1591 goes completely against the principles of a refcounted object.
1593 If you say Y here, the kernel will delay the release of kobjects
1594 on the last reference count to improve the visibility of this
1595 kind of kobject release bug.
1597 config HAVE_DEBUG_BUGVERBOSE
1600 menu "Debug kernel data structures"
1603 bool "Debug linked list manipulation"
1604 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1606 Enable this to turn on extended checks in the linked-list
1612 bool "Debug priority linked list manipulation"
1613 depends on DEBUG_KERNEL
1615 Enable this to turn on extended checks in the priority-ordered
1616 linked-list (plist) walking routines. This checks the entire
1617 list multiple times during each manipulation.
1622 bool "Debug SG table operations"
1623 depends on DEBUG_KERNEL
1625 Enable this to turn on checks on scatter-gather tables. This can
1626 help find problems with drivers that do not properly initialize
1631 config DEBUG_NOTIFIERS
1632 bool "Debug notifier call chains"
1633 depends on DEBUG_KERNEL
1635 Enable this to turn on sanity checking for notifier call chains.
1636 This is most useful for kernel developers to make sure that
1637 modules properly unregister themselves from notifier chains.
1638 This is a relatively cheap check but if you care about maximum
1641 config BUG_ON_DATA_CORRUPTION
1642 bool "Trigger a BUG when data corruption is detected"
1645 Select this option if the kernel should BUG when it encounters
1646 data corruption in kernel memory structures when they get checked
1651 config DEBUG_MAPLE_TREE
1652 bool "Debug maple trees"
1653 depends on DEBUG_KERNEL
1655 Enable maple tree debugging information and extra validations.
1661 config DEBUG_CREDENTIALS
1662 bool "Debug credential management"
1663 depends on DEBUG_KERNEL
1665 Enable this to turn on some debug checking for credential
1666 management. The additional code keeps track of the number of
1667 pointers from task_structs to any given cred struct, and checks to
1668 see that this number never exceeds the usage count of the cred
1671 Furthermore, if SELinux is enabled, this also checks that the
1672 security pointer in the cred struct is never seen to be invalid.
1676 source "kernel/rcu/Kconfig.debug"
1678 config DEBUG_WQ_FORCE_RR_CPU
1679 bool "Force round-robin CPU selection for unbound work items"
1680 depends on DEBUG_KERNEL
1683 Workqueue used to implicitly guarantee that work items queued
1684 without explicit CPU specified are put on the local CPU. This
1685 guarantee is no longer true and while local CPU is still
1686 preferred work items may be put on foreign CPUs. Kernel
1687 parameter "workqueue.debug_force_rr_cpu" is added to force
1688 round-robin CPU selection to flush out usages which depend on the
1689 now broken guarantee. This config option enables the debug
1690 feature by default. When enabled, memory and cache locality will
1693 config CPU_HOTPLUG_STATE_CONTROL
1694 bool "Enable CPU hotplug state control"
1695 depends on DEBUG_KERNEL
1696 depends on HOTPLUG_CPU
1699 Allows to write steps between "offline" and "online" to the CPUs
1700 sysfs target file so states can be stepped granular. This is a debug
1701 option for now as the hotplug machinery cannot be stopped and
1702 restarted at arbitrary points yet.
1704 Say N if your are unsure.
1707 bool "Latency measuring infrastructure"
1708 depends on DEBUG_KERNEL
1709 depends on STACKTRACE_SUPPORT
1711 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1717 Enable this option if you want to use the LatencyTOP tool
1718 to find out which userspace is blocking on what kernel operations.
1720 source "kernel/trace/Kconfig"
1722 config PROVIDE_OHCI1394_DMA_INIT
1723 bool "Remote debugging over FireWire early on boot"
1724 depends on PCI && X86
1726 If you want to debug problems which hang or crash the kernel early
1727 on boot and the crashing machine has a FireWire port, you can use
1728 this feature to remotely access the memory of the crashed machine
1729 over FireWire. This employs remote DMA as part of the OHCI1394
1730 specification which is now the standard for FireWire controllers.
1732 With remote DMA, you can monitor the printk buffer remotely using
1733 firescope and access all memory below 4GB using fireproxy from gdb.
1734 Even controlling a kernel debugger is possible using remote DMA.
1738 If ohci1394_dma=early is used as boot parameter, it will initialize
1739 all OHCI1394 controllers which are found in the PCI config space.
1741 As all changes to the FireWire bus such as enabling and disabling
1742 devices cause a bus reset and thereby disable remote DMA for all
1743 devices, be sure to have the cable plugged and FireWire enabled on
1744 the debugging host before booting the debug target for debugging.
1746 This code (~1k) is freed after boot. By then, the firewire stack
1747 in charge of the OHCI-1394 controllers should be used instead.
1749 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1751 source "samples/Kconfig"
1753 config ARCH_HAS_DEVMEM_IS_ALLOWED
1756 config STRICT_DEVMEM
1757 bool "Filter access to /dev/mem"
1758 depends on MMU && DEVMEM
1759 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1760 default y if PPC || X86 || ARM64
1762 If this option is disabled, you allow userspace (root) access to all
1763 of memory, including kernel and userspace memory. Accidental
1764 access to this is obviously disastrous, but specific access can
1765 be used by people debugging the kernel. Note that with PAT support
1766 enabled, even in this case there are restrictions on /dev/mem
1767 use due to the cache aliasing requirements.
1769 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1770 file only allows userspace access to PCI space and the BIOS code and
1771 data regions. This is sufficient for dosemu and X and all common
1776 config IO_STRICT_DEVMEM
1777 bool "Filter I/O access to /dev/mem"
1778 depends on STRICT_DEVMEM
1780 If this option is disabled, you allow userspace (root) access to all
1781 io-memory regardless of whether a driver is actively using that
1782 range. Accidental access to this is obviously disastrous, but
1783 specific access can be used by people debugging kernel drivers.
1785 If this option is switched on, the /dev/mem file only allows
1786 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1787 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1788 if the driver using a given range cannot be disabled.
1792 menu "$(SRCARCH) Debugging"
1794 source "arch/$(SRCARCH)/Kconfig.debug"
1798 menu "Kernel Testing and Coverage"
1800 source "lib/kunit/Kconfig"
1802 config NOTIFIER_ERROR_INJECTION
1803 tristate "Notifier error injection"
1804 depends on DEBUG_KERNEL
1807 This option provides the ability to inject artificial errors to
1808 specified notifier chain callbacks. It is useful to test the error
1809 handling of notifier call chain failures.
1813 config PM_NOTIFIER_ERROR_INJECT
1814 tristate "PM notifier error injection module"
1815 depends on PM && NOTIFIER_ERROR_INJECTION
1816 default m if PM_DEBUG
1818 This option provides the ability to inject artificial errors to
1819 PM notifier chain callbacks. It is controlled through debugfs
1820 interface /sys/kernel/debug/notifier-error-inject/pm
1822 If the notifier call chain should be failed with some events
1823 notified, write the error code to "actions/<notifier event>/error".
1825 Example: Inject PM suspend error (-12 = -ENOMEM)
1827 # cd /sys/kernel/debug/notifier-error-inject/pm/
1828 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1829 # echo mem > /sys/power/state
1830 bash: echo: write error: Cannot allocate memory
1832 To compile this code as a module, choose M here: the module will
1833 be called pm-notifier-error-inject.
1837 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1838 tristate "OF reconfig notifier error injection module"
1839 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1841 This option provides the ability to inject artificial errors to
1842 OF reconfig notifier chain callbacks. It is controlled
1843 through debugfs interface under
1844 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1846 If the notifier call chain should be failed with some events
1847 notified, write the error code to "actions/<notifier event>/error".
1849 To compile this code as a module, choose M here: the module will
1850 be called of-reconfig-notifier-error-inject.
1854 config NETDEV_NOTIFIER_ERROR_INJECT
1855 tristate "Netdev notifier error injection module"
1856 depends on NET && NOTIFIER_ERROR_INJECTION
1858 This option provides the ability to inject artificial errors to
1859 netdevice notifier chain callbacks. It is controlled through debugfs
1860 interface /sys/kernel/debug/notifier-error-inject/netdev
1862 If the notifier call chain should be failed with some events
1863 notified, write the error code to "actions/<notifier event>/error".
1865 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1867 # cd /sys/kernel/debug/notifier-error-inject/netdev
1868 # echo -22 > actions/NETDEV_CHANGEMTU/error
1869 # ip link set eth0 mtu 1024
1870 RTNETLINK answers: Invalid argument
1872 To compile this code as a module, choose M here: the module will
1873 be called netdev-notifier-error-inject.
1877 config FUNCTION_ERROR_INJECTION
1878 bool "Fault-injections of functions"
1879 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1881 Add fault injections into various functions that are annotated with
1882 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
1883 value of theses functions. This is useful to test error paths of code.
1887 config FAULT_INJECTION
1888 bool "Fault-injection framework"
1889 depends on DEBUG_KERNEL
1891 Provide fault-injection framework.
1892 For more details, see Documentation/fault-injection/.
1895 bool "Fault-injection capability for kmalloc"
1896 depends on FAULT_INJECTION
1897 depends on SLAB || SLUB
1899 Provide fault-injection capability for kmalloc.
1901 config FAIL_PAGE_ALLOC
1902 bool "Fault-injection capability for alloc_pages()"
1903 depends on FAULT_INJECTION
1905 Provide fault-injection capability for alloc_pages().
1907 config FAULT_INJECTION_USERCOPY
1908 bool "Fault injection capability for usercopy functions"
1909 depends on FAULT_INJECTION
1911 Provides fault-injection capability to inject failures
1912 in usercopy functions (copy_from_user(), get_user(), ...).
1914 config FAIL_MAKE_REQUEST
1915 bool "Fault-injection capability for disk IO"
1916 depends on FAULT_INJECTION && BLOCK
1918 Provide fault-injection capability for disk IO.
1920 config FAIL_IO_TIMEOUT
1921 bool "Fault-injection capability for faking disk interrupts"
1922 depends on FAULT_INJECTION && BLOCK
1924 Provide fault-injection capability on end IO handling. This
1925 will make the block layer "forget" an interrupt as configured,
1926 thus exercising the error handling.
1928 Only works with drivers that use the generic timeout handling,
1929 for others it won't do anything.
1932 bool "Fault-injection capability for futexes"
1934 depends on FAULT_INJECTION && FUTEX
1936 Provide fault-injection capability for futexes.
1938 config FAULT_INJECTION_DEBUG_FS
1939 bool "Debugfs entries for fault-injection capabilities"
1940 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1942 Enable configuration of fault-injection capabilities via debugfs.
1944 config FAIL_FUNCTION
1945 bool "Fault-injection capability for functions"
1946 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1948 Provide function-based fault-injection capability.
1949 This will allow you to override a specific function with a return
1950 with given return value. As a result, function caller will see
1951 an error value and have to handle it. This is useful to test the
1952 error handling in various subsystems.
1954 config FAIL_MMC_REQUEST
1955 bool "Fault-injection capability for MMC IO"
1956 depends on FAULT_INJECTION_DEBUG_FS && MMC
1958 Provide fault-injection capability for MMC IO.
1959 This will make the mmc core return data errors. This is
1960 useful to test the error handling in the mmc block device
1961 and to test how the mmc host driver handles retries from
1965 bool "Fault-injection capability for SunRPC"
1966 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1968 Provide fault-injection capability for SunRPC and
1971 config FAULT_INJECTION_STACKTRACE_FILTER
1972 bool "stacktrace filter for fault-injection capabilities"
1973 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1976 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1978 Provide stacktrace filter for fault-injection capabilities
1980 config ARCH_HAS_KCOV
1983 An architecture should select this when it can successfully
1984 build and run with CONFIG_KCOV. This typically requires
1985 disabling instrumentation for some early boot code.
1987 config CC_HAS_SANCOV_TRACE_PC
1988 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1992 bool "Code coverage for fuzzing"
1993 depends on ARCH_HAS_KCOV
1994 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1995 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
1996 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
1998 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1999 select OBJTOOL if HAVE_NOINSTR_HACK
2001 KCOV exposes kernel code coverage information in a form suitable
2002 for coverage-guided fuzzing (randomized testing).
2004 If RANDOMIZE_BASE is enabled, PC values will not be stable across
2005 different machines and across reboots. If you need stable PC values,
2006 disable RANDOMIZE_BASE.
2008 For more details, see Documentation/dev-tools/kcov.rst.
2010 config KCOV_ENABLE_COMPARISONS
2011 bool "Enable comparison operands collection by KCOV"
2013 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2015 KCOV also exposes operands of every comparison in the instrumented
2016 code along with operand sizes and PCs of the comparison instructions.
2017 These operands can be used by fuzzing engines to improve the quality
2018 of fuzzing coverage.
2020 config KCOV_INSTRUMENT_ALL
2021 bool "Instrument all code by default"
2025 If you are doing generic system call fuzzing (like e.g. syzkaller),
2026 then you will want to instrument the whole kernel and you should
2027 say y here. If you are doing more targeted fuzzing (like e.g.
2028 filesystem fuzzing with AFL) then you will want to enable coverage
2029 for more specific subsets of files, and should say n here.
2031 config KCOV_IRQ_AREA_SIZE
2032 hex "Size of interrupt coverage collection area in words"
2036 KCOV uses preallocated per-cpu areas to collect coverage from
2037 soft interrupts. This specifies the size of those areas in the
2038 number of unsigned long words.
2040 menuconfig RUNTIME_TESTING_MENU
2041 bool "Runtime Testing"
2044 if RUNTIME_TESTING_MENU
2047 tristate "Linux Kernel Dump Test Tool Module"
2050 This module enables testing of the different dumping mechanisms by
2051 inducing system failures at predefined crash points.
2052 If you don't need it: say N
2053 Choose M here to compile this code as a module. The module will be
2056 Documentation on how to use the module can be found in
2057 Documentation/fault-injection/provoke-crashes.rst
2059 config CPUMASK_KUNIT_TEST
2060 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2062 default KUNIT_ALL_TESTS
2064 Enable to turn on cpumask tests, running at boot or module load time.
2066 For more information on KUnit and unit tests in general, please refer
2067 to the KUnit documentation in Documentation/dev-tools/kunit/.
2071 config TEST_LIST_SORT
2072 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2074 default KUNIT_ALL_TESTS
2076 Enable this to turn on 'list_sort()' function test. This test is
2077 executed only once during system boot (so affects only boot time),
2078 or at module load time.
2082 config TEST_MIN_HEAP
2083 tristate "Min heap test"
2084 depends on DEBUG_KERNEL || m
2086 Enable this to turn on min heap function tests. This test is
2087 executed only once during system boot (so affects only boot time),
2088 or at module load time.
2093 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2095 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2096 default KUNIT_ALL_TESTS
2098 This option enables the self-test function of 'sort()' at boot,
2099 or at module load time.
2104 tristate "64bit/32bit division and modulo test"
2105 depends on DEBUG_KERNEL || m
2107 Enable this to turn on 'do_div()' function test. This test is
2108 executed only once during system boot (so affects only boot time),
2109 or at module load time.
2113 config KPROBES_SANITY_TEST
2114 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2115 depends on DEBUG_KERNEL
2118 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2119 default KUNIT_ALL_TESTS
2121 This option provides for testing basic kprobes functionality on
2122 boot. Samples of kprobe and kretprobe are inserted and
2123 verified for functionality.
2125 Say N if you are unsure.
2127 config FPROBE_SANITY_TEST
2128 bool "Self test for fprobe"
2129 depends on DEBUG_KERNEL
2133 This option will enable testing the fprobe when the system boot.
2134 A series of tests are made to verify that the fprobe is functioning
2137 Say N if you are unsure.
2139 config BACKTRACE_SELF_TEST
2140 tristate "Self test for the backtrace code"
2141 depends on DEBUG_KERNEL
2143 This option provides a kernel module that can be used to test
2144 the kernel stack backtrace code. This option is not useful
2145 for distributions or general kernels, but only for kernel
2146 developers working on architecture code.
2148 Note that if you want to also test saved backtraces, you will
2149 have to enable STACKTRACE as well.
2151 Say N if you are unsure.
2153 config TEST_REF_TRACKER
2154 tristate "Self test for reference tracker"
2155 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2158 This option provides a kernel module performing tests
2159 using reference tracker infrastructure.
2161 Say N if you are unsure.
2164 tristate "Red-Black tree test"
2165 depends on DEBUG_KERNEL
2167 A benchmark measuring the performance of the rbtree library.
2168 Also includes rbtree invariant checks.
2170 config REED_SOLOMON_TEST
2171 tristate "Reed-Solomon library test"
2172 depends on DEBUG_KERNEL || m
2174 select REED_SOLOMON_ENC16
2175 select REED_SOLOMON_DEC16
2177 This option enables the self-test function of rslib at boot,
2178 or at module load time.
2182 config INTERVAL_TREE_TEST
2183 tristate "Interval tree test"
2184 depends on DEBUG_KERNEL
2185 select INTERVAL_TREE
2187 A benchmark measuring the performance of the interval tree library
2190 tristate "Per cpu operations test"
2191 depends on m && DEBUG_KERNEL
2193 Enable this option to build test module which validates per-cpu
2198 config ATOMIC64_SELFTEST
2199 tristate "Perform an atomic64_t self-test"
2201 Enable this option to test the atomic64_t functions at boot or
2202 at module load time.
2206 config ASYNC_RAID6_TEST
2207 tristate "Self test for hardware accelerated raid6 recovery"
2208 depends on ASYNC_RAID6_RECOV
2211 This is a one-shot self test that permutes through the
2212 recovery of all the possible two disk failure scenarios for a
2213 N-disk array. Recovery is performed with the asynchronous
2214 raid6 recovery routines, and will optionally use an offload
2215 engine if one is available.
2220 tristate "Test functions located in the hexdump module at runtime"
2222 config STRING_SELFTEST
2223 tristate "Test string functions at runtime"
2225 config TEST_STRING_HELPERS
2226 tristate "Test functions located in the string_helpers module at runtime"
2229 tristate "Test strscpy*() family of functions at runtime"
2232 tristate "Test kstrto*() family of functions at runtime"
2235 tristate "Test printf() family of functions at runtime"
2238 tristate "Test scanf() family of functions at runtime"
2241 tristate "Test bitmap_*() family of functions at runtime"
2243 Enable this option to test the bitmap functions at boot.
2248 tristate "Test functions located in the uuid module at runtime"
2251 tristate "Test the XArray code at runtime"
2253 config TEST_MAPLE_TREE
2254 select DEBUG_MAPLE_TREE
2255 tristate "Test the Maple Tree code at runtime"
2257 config TEST_RHASHTABLE
2258 tristate "Perform selftest on resizable hash table"
2260 Enable this option to test the rhashtable functions at boot.
2265 tristate "Perform selftest on siphash functions"
2267 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2268 functions on boot (or module load).
2270 This is intended to help people writing architecture-specific
2271 optimized versions. If unsure, say N.
2274 tristate "Perform selftest on IDA functions"
2277 tristate "Perform selftest on priority array manager"
2280 Enable this option to test priority array manager on boot
2285 config TEST_IRQ_TIMINGS
2286 bool "IRQ timings selftest"
2287 depends on IRQ_TIMINGS
2289 Enable this option to test the irq timings code on boot.
2294 tristate "Test module loading with 'hello world' module"
2297 This builds the "test_module" module that emits "Hello, world"
2298 on printk when loaded. It is designed to be used for basic
2299 evaluation of the module loading subsystem (for example when
2300 validating module verification). It lacks any extra dependencies,
2301 and will not normally be loaded by the system unless explicitly
2307 tristate "Test module for compilation of bitops operations"
2310 This builds the "test_bitops" module that is much like the
2311 TEST_LKM module except that it does a basic exercise of the
2312 set/clear_bit macros and get_count_order/long to make sure there are
2313 no compiler warnings from C=1 sparse checker or -Wextra
2314 compilations. It has no dependencies and doesn't run or load unless
2315 explicitly requested by name. for example: modprobe test_bitops.
2320 tristate "Test module for stress/performance analysis of vmalloc allocator"
2325 This builds the "test_vmalloc" module that should be used for
2326 stress and performance analysis. So, any new change for vmalloc
2327 subsystem can be evaluated from performance and stability point
2332 config TEST_USER_COPY
2333 tristate "Test user/kernel boundary protections"
2336 This builds the "test_user_copy" module that runs sanity checks
2337 on the copy_to/from_user infrastructure, making sure basic
2338 user/kernel boundary testing is working. If it fails to load,
2339 a regression has been detected in the user/kernel memory boundary
2345 tristate "Test BPF filter functionality"
2348 This builds the "test_bpf" module that runs various test vectors
2349 against the BPF interpreter or BPF JIT compiler depending on the
2350 current setting. This is in particular useful for BPF JIT compiler
2351 development, but also to run regression tests against changes in
2352 the interpreter code. It also enables test stubs for eBPF maps and
2353 verifier used by user space verifier testsuite.
2357 config TEST_BLACKHOLE_DEV
2358 tristate "Test blackhole netdev functionality"
2361 This builds the "test_blackhole_dev" module that validates the
2362 data path through this blackhole netdev.
2366 config FIND_BIT_BENCHMARK
2367 tristate "Test find_bit functions"
2369 This builds the "test_find_bit" module that measure find_*_bit()
2370 functions performance.
2374 config TEST_FIRMWARE
2375 tristate "Test firmware loading via userspace interface"
2376 depends on FW_LOADER
2378 This builds the "test_firmware" module that creates a userspace
2379 interface for testing firmware loading. This can be used to
2380 control the triggering of firmware loading without needing an
2381 actual firmware-using device. The contents can be rechecked by
2387 tristate "sysctl test driver"
2388 depends on PROC_SYSCTL
2390 This builds the "test_sysctl" module. This driver enables to test the
2391 proc sysctl interfaces available to drivers safely without affecting
2392 production knobs which might alter system functionality.
2396 config BITFIELD_KUNIT
2397 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2399 default KUNIT_ALL_TESTS
2401 Enable this option to test the bitfield functions at boot.
2403 KUnit tests run during boot and output the results to the debug log
2404 in TAP format (http://testanything.org/). Only useful for kernel devs
2405 running the KUnit test harness, and not intended for inclusion into a
2408 For more information on KUnit and unit tests in general please refer
2409 to the KUnit documentation in Documentation/dev-tools/kunit/.
2413 config HASH_KUNIT_TEST
2414 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2416 default KUNIT_ALL_TESTS
2418 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2419 integer (<linux/hash.h>) hash functions on boot.
2421 KUnit tests run during boot and output the results to the debug log
2422 in TAP format (https://testanything.org/). Only useful for kernel devs
2423 running the KUnit test harness, and not intended for inclusion into a
2426 For more information on KUnit and unit tests in general please refer
2427 to the KUnit documentation in Documentation/dev-tools/kunit/.
2429 This is intended to help people writing architecture-specific
2430 optimized versions. If unsure, say N.
2432 config RESOURCE_KUNIT_TEST
2433 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2435 default KUNIT_ALL_TESTS
2437 This builds the resource API unit test.
2438 Tests the logic of API provided by resource.c and ioport.h.
2439 For more information on KUnit and unit tests in general please refer
2440 to the KUnit documentation in Documentation/dev-tools/kunit/.
2444 config SYSCTL_KUNIT_TEST
2445 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2447 default KUNIT_ALL_TESTS
2449 This builds the proc sysctl unit test, which runs on boot.
2450 Tests the API contract and implementation correctness of sysctl.
2451 For more information on KUnit and unit tests in general please refer
2452 to the KUnit documentation in Documentation/dev-tools/kunit/.
2456 config LIST_KUNIT_TEST
2457 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2459 default KUNIT_ALL_TESTS
2461 This builds the linked list KUnit test suite.
2462 It tests that the API and basic functionality of the list_head type
2463 and associated macros.
2465 KUnit tests run during boot and output the results to the debug log
2466 in TAP format (https://testanything.org/). Only useful for kernel devs
2467 running the KUnit test harness, and not intended for inclusion into a
2470 For more information on KUnit and unit tests in general please refer
2471 to the KUnit documentation in Documentation/dev-tools/kunit/.
2475 config LINEAR_RANGES_TEST
2476 tristate "KUnit test for linear_ranges"
2478 select LINEAR_RANGES
2480 This builds the linear_ranges unit test, which runs on boot.
2481 Tests the linear_ranges logic correctness.
2482 For more information on KUnit and unit tests in general please refer
2483 to the KUnit documentation in Documentation/dev-tools/kunit/.
2487 config CMDLINE_KUNIT_TEST
2488 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2490 default KUNIT_ALL_TESTS
2492 This builds the cmdline API unit test.
2493 Tests the logic of API provided by cmdline.c.
2494 For more information on KUnit and unit tests in general please refer
2495 to the KUnit documentation in Documentation/dev-tools/kunit/.
2500 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2502 default KUNIT_ALL_TESTS
2504 This builds the bits unit test.
2505 Tests the logic of macros defined in bits.h.
2506 For more information on KUnit and unit tests in general please refer
2507 to the KUnit documentation in Documentation/dev-tools/kunit/.
2511 config SLUB_KUNIT_TEST
2512 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2513 depends on SLUB_DEBUG && KUNIT
2514 default KUNIT_ALL_TESTS
2516 This builds SLUB allocator unit test.
2517 Tests SLUB cache debugging functionality.
2518 For more information on KUnit and unit tests in general please refer
2519 to the KUnit documentation in Documentation/dev-tools/kunit/.
2523 config RATIONAL_KUNIT_TEST
2524 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2525 depends on KUNIT && RATIONAL
2526 default KUNIT_ALL_TESTS
2528 This builds the rational math unit test.
2529 For more information on KUnit and unit tests in general please refer
2530 to the KUnit documentation in Documentation/dev-tools/kunit/.
2534 config MEMCPY_KUNIT_TEST
2535 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2537 default KUNIT_ALL_TESTS
2539 Builds unit tests for memcpy(), memmove(), and memset() functions.
2540 For more information on KUnit and unit tests in general please refer
2541 to the KUnit documentation in Documentation/dev-tools/kunit/.
2545 config IS_SIGNED_TYPE_KUNIT_TEST
2546 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2548 default KUNIT_ALL_TESTS
2550 Builds unit tests for the is_signed_type() macro.
2552 For more information on KUnit and unit tests in general please refer
2553 to the KUnit documentation in Documentation/dev-tools/kunit/.
2557 config OVERFLOW_KUNIT_TEST
2558 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2560 default KUNIT_ALL_TESTS
2562 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2565 For more information on KUnit and unit tests in general please refer
2566 to the KUnit documentation in Documentation/dev-tools/kunit/.
2570 config STACKINIT_KUNIT_TEST
2571 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2573 default KUNIT_ALL_TESTS
2575 Test if the kernel is zero-initializing stack variables and
2576 padding. Coverage is controlled by compiler flags,
2577 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2578 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2579 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2581 config FORTIFY_KUNIT_TEST
2582 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2583 depends on KUNIT && FORTIFY_SOURCE
2584 default KUNIT_ALL_TESTS
2586 Builds unit tests for checking internals of FORTIFY_SOURCE as used
2587 by the str*() and mem*() family of functions. For testing runtime
2588 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2590 config HW_BREAKPOINT_KUNIT_TEST
2591 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2592 depends on HAVE_HW_BREAKPOINT
2594 default KUNIT_ALL_TESTS
2596 Tests for hw_breakpoint constraints accounting.
2601 tristate "udelay test driver"
2603 This builds the "udelay_test" module that helps to make sure
2604 that udelay() is working properly.
2608 config TEST_STATIC_KEYS
2609 tristate "Test static keys"
2612 Test the static key interfaces.
2616 config TEST_DYNAMIC_DEBUG
2617 tristate "Test DYNAMIC_DEBUG"
2618 depends on DYNAMIC_DEBUG
2620 This module registers a tracer callback to count enabled
2621 pr_debugs in a 'do_debugging' function, then alters their
2622 enablements, calls the function, and compares counts.
2627 tristate "kmod stress tester"
2629 depends on NETDEVICES && NET_CORE && INET # for TUN
2631 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2637 Test the kernel's module loading mechanism: kmod. kmod implements
2638 support to load modules using the Linux kernel's usermode helper.
2639 This test provides a series of tests against kmod.
2641 Although technically you can either build test_kmod as a module or
2642 into the kernel we disallow building it into the kernel since
2643 it stress tests request_module() and this will very likely cause
2644 some issues by taking over precious threads available from other
2645 module load requests, ultimately this could be fatal.
2649 tools/testing/selftests/kmod/kmod.sh --help
2653 config TEST_DEBUG_VIRTUAL
2654 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2655 depends on DEBUG_VIRTUAL
2657 Test the kernel's ability to detect incorrect calls to
2658 virt_to_phys() done against the non-linear part of the
2659 kernel's virtual address map.
2663 config TEST_MEMCAT_P
2664 tristate "Test memcat_p() helper function"
2666 Test the memcat_p() helper for correctly merging two
2667 pointer arrays together.
2671 config TEST_LIVEPATCH
2672 tristate "Test livepatching"
2674 depends on DYNAMIC_DEBUG
2675 depends on LIVEPATCH
2678 Test kernel livepatching features for correctness. The tests will
2679 load test modules that will be livepatched in various scenarios.
2681 To run all the livepatching tests:
2683 make -C tools/testing/selftests TARGETS=livepatch run_tests
2685 Alternatively, individual tests may be invoked:
2687 tools/testing/selftests/livepatch/test-callbacks.sh
2688 tools/testing/selftests/livepatch/test-livepatch.sh
2689 tools/testing/selftests/livepatch/test-shadow-vars.sh
2694 tristate "Perform selftest on object aggreration manager"
2698 Enable this option to test object aggregation manager on boot
2702 tristate "Test heap/page initialization"
2704 Test if the kernel is zero-initializing heap and page allocations.
2705 This can be useful to test init_on_alloc and init_on_free features.
2710 tristate "Test HMM (Heterogeneous Memory Management)"
2711 depends on TRANSPARENT_HUGEPAGE
2712 depends on DEVICE_PRIVATE
2716 This is a pseudo device driver solely for testing HMM.
2717 Say M here if you want to build the HMM test module.
2718 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2722 config TEST_FREE_PAGES
2723 tristate "Test freeing pages"
2725 Test that a memory leak does not occur due to a race between
2726 freeing a block of pages and a speculative page reference.
2727 Loading this module is safe if your kernel has the bug fixed.
2728 If the bug is not fixed, it will leak gigabytes of memory and
2729 probably OOM your system.
2732 tristate "Test floating point operations in kernel space"
2733 depends on X86 && !KCOV_INSTRUMENT_ALL
2735 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2736 which will trigger a sequence of floating point operations. This is used
2737 for self-testing floating point control register setting in
2742 config TEST_CLOCKSOURCE_WATCHDOG
2743 tristate "Test clocksource watchdog in kernel space"
2744 depends on CLOCKSOURCE_WATCHDOG
2746 Enable this option to create a kernel module that will trigger
2747 a test of the clocksource watchdog. This module may be loaded
2748 via modprobe or insmod in which case it will run upon being
2749 loaded, or it may be built in, in which case it will run
2754 endif # RUNTIME_TESTING_MENU
2756 config ARCH_USE_MEMTEST
2759 An architecture should select this when it uses early_memtest()
2760 during boot process.
2764 depends on ARCH_USE_MEMTEST
2766 This option adds a kernel parameter 'memtest', which allows memtest
2767 to be set and executed.
2768 memtest=0, mean disabled; -- default
2769 memtest=1, mean do 1 test pattern;
2771 memtest=17, mean do 17 test patterns.
2772 If you are unsure how to answer this question, answer N.
2776 config HYPERV_TESTING
2777 bool "Microsoft Hyper-V driver testing"
2779 depends on HYPERV && DEBUG_FS
2781 Select this option to enable Hyper-V vmbus testing.
2783 endmenu # "Kernel Testing and Coverage"
2787 config RUST_DEBUG_ASSERTIONS
2788 bool "Debug assertions"
2791 Enables rustc's `-Cdebug-assertions` codegen option.
2793 This flag lets you turn `cfg(debug_assertions)` conditional
2794 compilation on or off. This can be used to enable extra debugging
2795 code in development but not in production. For example, it controls
2796 the behavior of the standard library's `debug_assert!` macro.
2798 Note that this will apply to all Rust code, including `core`.
2802 config RUST_OVERFLOW_CHECKS
2803 bool "Overflow checks"
2807 Enables rustc's `-Coverflow-checks` codegen option.
2809 This flag allows you to control the behavior of runtime integer
2810 overflow. When overflow-checks are enabled, a Rust panic will occur
2813 Note that this will apply to all Rust code, including `core`.
2819 source "Documentation/Kconfig"
2821 endmenu # Kernel hacking
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