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.
316 prompt "Compressed Debug information"
318 Compress the resulting debug info. Results in smaller debug info sections,
319 but requires that consumers are able to decompress the results.
321 If unsure, choose DEBUG_INFO_COMPRESSED_NONE.
323 config DEBUG_INFO_COMPRESSED_NONE
324 bool "Don't compress debug information"
326 Don't compress debug info sections.
328 config DEBUG_INFO_COMPRESSED_ZLIB
329 bool "Compress debugging information with zlib"
330 depends on $(cc-option,-gz=zlib)
331 depends on $(ld-option,--compress-debug-sections=zlib)
333 Compress the debug information using zlib. Requires GCC 5.0+ or Clang
334 5.0+, binutils 2.26+, and zlib.
336 Users of dpkg-deb via scripts/package/builddeb may find an increase in
337 size of their debug .deb packages with this config set, due to the
338 debug info being compressed with zlib, then the object files being
339 recompressed with a different compression scheme. But this is still
340 preferable to setting $KDEB_COMPRESS to "none" which would be even
343 config DEBUG_INFO_COMPRESSED_ZSTD
344 bool "Compress debugging information with zstd"
345 depends on $(cc-option,-gz=zstd)
346 depends on $(ld-option,--compress-debug-sections=zstd)
348 Compress the debug information using zstd. This may provide better
349 compression than zlib, for about the same time costs, but requires newer
350 toolchain support. Requires GCC 13.0+ or Clang 16.0+, binutils 2.40+, and
353 endchoice # "Compressed Debug information"
355 config DEBUG_INFO_SPLIT
356 bool "Produce split debuginfo in .dwo files"
357 depends on $(cc-option,-gsplit-dwarf)
359 Generate debug info into separate .dwo files. This significantly
360 reduces the build directory size for builds with DEBUG_INFO,
361 because it stores the information only once on disk in .dwo
362 files instead of multiple times in object files and executables.
363 In addition the debug information is also compressed.
365 Requires recent gcc (4.7+) and recent gdb/binutils.
366 Any tool that packages or reads debug information would need
367 to know about the .dwo files and include them.
368 Incompatible with older versions of ccache.
370 config DEBUG_INFO_BTF
371 bool "Generate BTF typeinfo"
372 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
373 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
374 depends on BPF_SYSCALL
375 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121
377 Generate deduplicated BTF type information from DWARF debug info.
378 Turning this on expects presence of pahole tool, which will convert
379 DWARF type info into equivalent deduplicated BTF type info.
381 config PAHOLE_HAS_SPLIT_BTF
382 def_bool PAHOLE_VERSION >= 119
384 config PAHOLE_HAS_BTF_TAG
385 def_bool PAHOLE_VERSION >= 123
386 depends on CC_IS_CLANG
388 Decide whether pahole emits btf_tag attributes (btf_type_tag and
389 btf_decl_tag) or not. Currently only clang compiler implements
390 these attributes, so make the config depend on CC_IS_CLANG.
392 config PAHOLE_HAS_LANG_EXCLUDE
393 def_bool PAHOLE_VERSION >= 124
395 Support for the --lang_exclude flag which makes pahole exclude
396 compilation units from the supplied language. Used in Kbuild to
397 omit Rust CUs which are not supported in version 1.24 of pahole,
398 otherwise it would emit malformed kernel and module binaries when
399 using DEBUG_INFO_BTF_MODULES.
401 config DEBUG_INFO_BTF_MODULES
403 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
405 Generate compact split BTF type information for kernel modules.
407 config MODULE_ALLOW_BTF_MISMATCH
408 bool "Allow loading modules with non-matching BTF type info"
409 depends on DEBUG_INFO_BTF_MODULES
411 For modules whose split BTF does not match vmlinux, load without
412 BTF rather than refusing to load. The default behavior with
413 module BTF enabled is to reject modules with such mismatches;
414 this option will still load module BTF where possible but ignore
415 it when a mismatch is found.
418 bool "Provide GDB scripts for kernel debugging"
420 This creates the required links to GDB helper scripts in the
421 build directory. If you load vmlinux into gdb, the helper
422 scripts will be automatically imported by gdb as well, and
423 additional functions are available to analyze a Linux kernel
424 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
430 int "Warn for stack frames larger than"
433 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
434 default 2048 if PARISC
435 default 1536 if (!64BIT && XTENSA)
436 default 1280 if KASAN && !64BIT
437 default 1024 if !64BIT
438 default 2048 if 64BIT
440 Tell the compiler to warn at build time for stack frames larger than this.
441 Setting this too low will cause a lot of warnings.
442 Setting it to 0 disables the warning.
444 config STRIP_ASM_SYMS
445 bool "Strip assembler-generated symbols during link"
448 Strip internal assembler-generated symbols during a link (symbols
449 that look like '.Lxxx') so they don't pollute the output of
450 get_wchan() and suchlike.
453 bool "Generate readable assembler code"
454 depends on DEBUG_KERNEL
457 Disable some compiler optimizations that tend to generate human unreadable
458 assembler output. This may make the kernel slightly slower, but it helps
459 to keep kernel developers who have to stare a lot at assembler listings
462 config HEADERS_INSTALL
463 bool "Install uapi headers to usr/include"
466 This option will install uapi headers (headers exported to user-space)
467 into the usr/include directory for use during the kernel build.
468 This is unneeded for building the kernel itself, but needed for some
469 user-space program samples. It is also needed by some features such
470 as uapi header sanity checks.
472 config DEBUG_SECTION_MISMATCH
473 bool "Enable full Section mismatch analysis"
476 The section mismatch analysis checks if there are illegal
477 references from one section to another section.
478 During linktime or runtime, some sections are dropped;
479 any use of code/data previously in these sections would
480 most likely result in an oops.
481 In the code, functions and variables are annotated with
482 __init,, etc. (see the full list in include/linux/init.h),
483 which results in the code/data being placed in specific sections.
484 The section mismatch analysis is always performed after a full
485 kernel build, and enabling this option causes the following
486 additional step to occur:
487 - Add the option -fno-inline-functions-called-once to gcc commands.
488 When inlining a function annotated with __init in a non-init
489 function, we would lose the section information and thus
490 the analysis would not catch the illegal reference.
491 This option tells gcc to inline less (but it does result in
494 config SECTION_MISMATCH_WARN_ONLY
495 bool "Make section mismatch errors non-fatal"
498 If you say N here, the build process will fail if there are any
499 section mismatch, instead of just throwing warnings.
503 config DEBUG_FORCE_FUNCTION_ALIGN_64B
504 bool "Force all function address 64B aligned"
505 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC || S390)
506 select FUNCTION_ALIGNMENT_64B
508 There are cases that a commit from one domain changes the function
509 address alignment of other domains, and cause magic performance
510 bump (regression or improvement). Enable this option will help to
511 verify if the bump is caused by function alignment changes, while
512 it will slightly increase the kernel size and affect icache usage.
514 It is mainly for debug and performance tuning use.
517 # Select this config option from the architecture Kconfig, if it
518 # is preferred to always offer frame pointers as a config
519 # option on the architecture (regardless of KERNEL_DEBUG):
521 config ARCH_WANT_FRAME_POINTERS
525 bool "Compile the kernel with frame pointers"
526 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
527 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
529 If you say Y here the resulting kernel image will be slightly
530 larger and slower, but it gives very useful debugging information
531 in case of kernel bugs. (precise oopses/stacktraces/warnings)
536 config STACK_VALIDATION
537 bool "Compile-time stack metadata validation"
538 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
542 Validate frame pointer rules at compile-time. This helps ensure that
543 runtime stack traces are more reliable.
545 For more information, see
546 tools/objtool/Documentation/objtool.txt.
548 config NOINSTR_VALIDATION
550 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
555 bool "Generate vmlinux.map file when linking"
558 Selecting this option will pass "-Map=vmlinux.map" to ld
559 when linking vmlinux. That file can be useful for verifying
560 and debugging magic section games, and for seeing which
561 pieces of code get eliminated with
562 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
564 config DEBUG_FORCE_WEAK_PER_CPU
565 bool "Force weak per-cpu definitions"
566 depends on DEBUG_KERNEL
568 s390 and alpha require percpu variables in modules to be
569 defined weak to work around addressing range issue which
570 puts the following two restrictions on percpu variable
573 1. percpu symbols must be unique whether static or not
574 2. percpu variables can't be defined inside a function
576 To ensure that generic code follows the above rules, this
577 option forces all percpu variables to be defined as weak.
579 endmenu # "Compiler options"
581 menu "Generic Kernel Debugging Instruments"
584 bool "Magic SysRq key"
587 If you say Y here, you will have some control over the system even
588 if the system crashes for example during kernel debugging (e.g., you
589 will be able to flush the buffer cache to disk, reboot the system
590 immediately or dump some status information). This is accomplished
591 by pressing various keys while holding SysRq (Alt+PrintScreen). It
592 also works on a serial console (on PC hardware at least), if you
593 send a BREAK and then within 5 seconds a command keypress. The
594 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
595 Don't say Y unless you really know what this hack does.
597 config MAGIC_SYSRQ_DEFAULT_ENABLE
598 hex "Enable magic SysRq key functions by default"
599 depends on MAGIC_SYSRQ
602 Specifies which SysRq key functions are enabled by default.
603 This may be set to 1 or 0 to enable or disable them all, or
604 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
606 config MAGIC_SYSRQ_SERIAL
607 bool "Enable magic SysRq key over serial"
608 depends on MAGIC_SYSRQ
611 Many embedded boards have a disconnected TTL level serial which can
612 generate some garbage that can lead to spurious false sysrq detects.
613 This option allows you to decide whether you want to enable the
616 config MAGIC_SYSRQ_SERIAL_SEQUENCE
617 string "Char sequence that enables magic SysRq over serial"
618 depends on MAGIC_SYSRQ_SERIAL
621 Specifies a sequence of characters that can follow BREAK to enable
622 SysRq on a serial console.
624 If unsure, leave an empty string and the option will not be enabled.
627 bool "Debug Filesystem"
629 debugfs is a virtual file system that kernel developers use to put
630 debugging files into. Enable this option to be able to read and
631 write to these files.
633 For detailed documentation on the debugfs API, see
634 Documentation/filesystems/.
639 prompt "Debugfs default access"
641 default DEBUG_FS_ALLOW_ALL
643 This selects the default access restrictions for debugfs.
644 It can be overridden with kernel command line option
645 debugfs=[on,no-mount,off]. The restrictions apply for API access
646 and filesystem registration.
648 config DEBUG_FS_ALLOW_ALL
651 No restrictions apply. Both API and filesystem registration
652 is on. This is the normal default operation.
654 config DEBUG_FS_DISALLOW_MOUNT
655 bool "Do not register debugfs as filesystem"
657 The API is open but filesystem is not loaded. Clients can still do
658 their work and read with debug tools that do not need
661 config DEBUG_FS_ALLOW_NONE
664 Access is off. Clients get -PERM when trying to create nodes in
665 debugfs tree and debugfs is not registered as a filesystem.
666 Client can then back-off or continue without debugfs access.
670 source "lib/Kconfig.kgdb"
671 source "lib/Kconfig.ubsan"
672 source "lib/Kconfig.kcsan"
676 menu "Networking Debugging"
678 source "net/Kconfig.debug"
680 endmenu # "Networking Debugging"
682 menu "Memory Debugging"
684 source "mm/Kconfig.debug"
687 bool "Debug object operations"
688 depends on DEBUG_KERNEL
690 If you say Y here, additional code will be inserted into the
691 kernel to track the life time of various objects and validate
692 the operations on those objects.
694 config DEBUG_OBJECTS_SELFTEST
695 bool "Debug objects selftest"
696 depends on DEBUG_OBJECTS
698 This enables the selftest of the object debug code.
700 config DEBUG_OBJECTS_FREE
701 bool "Debug objects in freed memory"
702 depends on DEBUG_OBJECTS
704 This enables checks whether a k/v free operation frees an area
705 which contains an object which has not been deactivated
706 properly. This can make kmalloc/kfree-intensive workloads
709 config DEBUG_OBJECTS_TIMERS
710 bool "Debug timer objects"
711 depends on DEBUG_OBJECTS
713 If you say Y here, additional code will be inserted into the
714 timer routines to track the life time of timer objects and
715 validate the timer operations.
717 config DEBUG_OBJECTS_WORK
718 bool "Debug work objects"
719 depends on DEBUG_OBJECTS
721 If you say Y here, additional code will be inserted into the
722 work queue routines to track the life time of work objects and
723 validate the work operations.
725 config DEBUG_OBJECTS_RCU_HEAD
726 bool "Debug RCU callbacks objects"
727 depends on DEBUG_OBJECTS
729 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
731 config DEBUG_OBJECTS_PERCPU_COUNTER
732 bool "Debug percpu counter objects"
733 depends on DEBUG_OBJECTS
735 If you say Y here, additional code will be inserted into the
736 percpu counter routines to track the life time of percpu counter
737 objects and validate the percpu counter operations.
739 config DEBUG_OBJECTS_ENABLE_DEFAULT
740 int "debug_objects bootup default value (0-1)"
743 depends on DEBUG_OBJECTS
745 Debug objects boot parameter default value
747 config SHRINKER_DEBUG
748 bool "Enable shrinker debugging support"
751 Say Y to enable the shrinker debugfs interface which provides
752 visibility into the kernel memory shrinkers subsystem.
753 Disable it to avoid an extra memory footprint.
755 config DEBUG_STACK_USAGE
756 bool "Stack utilization instrumentation"
757 depends on DEBUG_KERNEL && !IA64
759 Enables the display of the minimum amount of free stack which each
760 task has ever had available in the sysrq-T and sysrq-P debug output.
762 This option will slow down process creation somewhat.
764 config SCHED_STACK_END_CHECK
765 bool "Detect stack corruption on calls to schedule()"
766 depends on DEBUG_KERNEL
769 This option checks for a stack overrun on calls to schedule().
770 If the stack end location is found to be over written always panic as
771 the content of the corrupted region can no longer be trusted.
772 This is to ensure no erroneous behaviour occurs which could result in
773 data corruption or a sporadic crash at a later stage once the region
774 is examined. The runtime overhead introduced is minimal.
776 config ARCH_HAS_DEBUG_VM_PGTABLE
779 An architecture should select this when it can successfully
780 build and run DEBUG_VM_PGTABLE.
782 config DEBUG_VM_IRQSOFF
783 def_bool DEBUG_VM && !PREEMPT_RT
787 depends on DEBUG_KERNEL
789 Enable this to turn on extended checks in the virtual-memory system
790 that may impact performance.
794 config DEBUG_VM_SHOOT_LAZIES
795 bool "Debug MMU_LAZY_TLB_SHOOTDOWN implementation"
797 depends on MMU_LAZY_TLB_SHOOTDOWN
799 Enable additional IPIs that ensure lazy tlb mm references are removed
800 before the mm is freed.
804 config DEBUG_VM_MAPLE_TREE
805 bool "Debug VM maple trees"
807 select DEBUG_MAPLE_TREE
809 Enable VM maple tree debugging information and extra validations.
814 bool "Debug VM red-black trees"
817 Enable VM red-black tree debugging information and extra validations.
821 config DEBUG_VM_PGFLAGS
822 bool "Debug page-flags operations"
825 Enables extra validation on page flags operations.
829 config DEBUG_VM_PGTABLE
830 bool "Debug arch page table for semantics compliance"
832 depends on ARCH_HAS_DEBUG_VM_PGTABLE
833 default y if DEBUG_VM
835 This option provides a debug method which can be used to test
836 architecture page table helper functions on various platforms in
837 verifying if they comply with expected generic MM semantics. This
838 will help architecture code in making sure that any changes or
839 new additions of these helpers still conform to expected
840 semantics of the generic MM. Platforms will have to opt in for
841 this through ARCH_HAS_DEBUG_VM_PGTABLE.
845 config ARCH_HAS_DEBUG_VIRTUAL
849 bool "Debug VM translations"
850 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
852 Enable some costly sanity checks in virtual to page code. This can
853 catch mistakes with virt_to_page() and friends.
857 config DEBUG_NOMMU_REGIONS
858 bool "Debug the global anon/private NOMMU mapping region tree"
859 depends on DEBUG_KERNEL && !MMU
861 This option causes the global tree of anonymous and private mapping
862 regions to be regularly checked for invalid topology.
864 config DEBUG_MEMORY_INIT
865 bool "Debug memory initialisation" if EXPERT
868 Enable this for additional checks during memory initialisation.
869 The sanity checks verify aspects of the VM such as the memory model
870 and other information provided by the architecture. Verbose
871 information will be printed at KERN_DEBUG loglevel depending
872 on the mminit_loglevel= command-line option.
876 config MEMORY_NOTIFIER_ERROR_INJECT
877 tristate "Memory hotplug notifier error injection module"
878 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
880 This option provides the ability to inject artificial errors to
881 memory hotplug notifier chain callbacks. It is controlled through
882 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
884 If the notifier call chain should be failed with some events
885 notified, write the error code to "actions/<notifier event>/error".
887 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
889 # cd /sys/kernel/debug/notifier-error-inject/memory
890 # echo -12 > actions/MEM_GOING_OFFLINE/error
891 # echo offline > /sys/devices/system/memory/memoryXXX/state
892 bash: echo: write error: Cannot allocate memory
894 To compile this code as a module, choose M here: the module will
895 be called memory-notifier-error-inject.
899 config DEBUG_PER_CPU_MAPS
900 bool "Debug access to per_cpu maps"
901 depends on DEBUG_KERNEL
904 Say Y to verify that the per_cpu map being accessed has
905 been set up. This adds a fair amount of code to kernel memory
906 and decreases performance.
910 config DEBUG_KMAP_LOCAL
911 bool "Debug kmap_local temporary mappings"
912 depends on DEBUG_KERNEL && KMAP_LOCAL
914 This option enables additional error checking for the kmap_local
915 infrastructure. Disable for production use.
917 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
920 config DEBUG_KMAP_LOCAL_FORCE_MAP
921 bool "Enforce kmap_local temporary mappings"
922 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
924 select DEBUG_KMAP_LOCAL
926 This option enforces temporary mappings through the kmap_local
927 mechanism for non-highmem pages and on non-highmem systems.
928 Disable this for production systems!
931 bool "Highmem debugging"
932 depends on DEBUG_KERNEL && HIGHMEM
933 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
934 select DEBUG_KMAP_LOCAL
936 This option enables additional error checking for high memory
937 systems. Disable for production systems.
939 config HAVE_DEBUG_STACKOVERFLOW
942 config DEBUG_STACKOVERFLOW
943 bool "Check for stack overflows"
944 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
946 Say Y here if you want to check for overflows of kernel, IRQ
947 and exception stacks (if your architecture uses them). This
948 option will show detailed messages if free stack space drops
949 below a certain limit.
951 These kinds of bugs usually occur when call-chains in the
952 kernel get too deep, especially when interrupts are
955 Use this in cases where you see apparently random memory
956 corruption, especially if it appears in 'struct thread_info'
958 If in doubt, say "N".
960 source "lib/Kconfig.kasan"
961 source "lib/Kconfig.kfence"
962 source "lib/Kconfig.kmsan"
964 endmenu # "Memory Debugging"
967 bool "Debug shared IRQ handlers"
968 depends on DEBUG_KERNEL
970 Enable this to generate a spurious interrupt just before a shared
971 interrupt handler is deregistered (generating one when registering
972 is currently disabled). Drivers need to handle this correctly. Some
973 don't and need to be caught.
975 menu "Debug Oops, Lockups and Hangs"
980 Say Y here to enable the kernel to panic when it oopses. This
981 has the same effect as setting oops=panic on the kernel command
984 This feature is useful to ensure that the kernel does not do
985 anything erroneous after an oops which could result in data
986 corruption or other issues.
990 config PANIC_ON_OOPS_VALUE
993 default 0 if !PANIC_ON_OOPS
994 default 1 if PANIC_ON_OOPS
1000 Set the timeout value (in seconds) until a reboot occurs when
1001 the kernel panics. If n = 0, then we wait forever. A timeout
1002 value n > 0 will wait n seconds before rebooting, while a timeout
1003 value n < 0 will reboot immediately.
1005 config LOCKUP_DETECTOR
1008 config SOFTLOCKUP_DETECTOR
1009 bool "Detect Soft Lockups"
1010 depends on DEBUG_KERNEL && !S390
1011 select LOCKUP_DETECTOR
1013 Say Y here to enable the kernel to act as a watchdog to detect
1016 Softlockups are bugs that cause the kernel to loop in kernel
1017 mode for more than 20 seconds, without giving other tasks a
1018 chance to run. The current stack trace is displayed upon
1019 detection and the system will stay locked up.
1021 config BOOTPARAM_SOFTLOCKUP_PANIC
1022 bool "Panic (Reboot) On Soft Lockups"
1023 depends on SOFTLOCKUP_DETECTOR
1025 Say Y here to enable the kernel to panic on "soft lockups",
1026 which are bugs that cause the kernel to loop in kernel
1027 mode for more than 20 seconds (configurable using the watchdog_thresh
1028 sysctl), without giving other tasks a chance to run.
1030 The panic can be used in combination with panic_timeout,
1031 to cause the system to reboot automatically after a
1032 lockup has been detected. This feature is useful for
1033 high-availability systems that have uptime guarantees and
1034 where a lockup must be resolved ASAP.
1038 config HARDLOCKUP_DETECTOR_PERF
1040 select SOFTLOCKUP_DETECTOR
1043 # Enables a timestamp based low pass filter to compensate for perf based
1044 # hard lockup detection which runs too fast due to turbo modes.
1046 config HARDLOCKUP_CHECK_TIMESTAMP
1050 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1051 # lockup detector rather than the perf based detector.
1053 config HARDLOCKUP_DETECTOR
1054 bool "Detect Hard Lockups"
1055 depends on DEBUG_KERNEL && !S390
1056 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1057 select LOCKUP_DETECTOR
1058 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1060 Say Y here to enable the kernel to act as a watchdog to detect
1063 Hardlockups are bugs that cause the CPU to loop in kernel mode
1064 for more than 10 seconds, without letting other interrupts have a
1065 chance to run. The current stack trace is displayed upon detection
1066 and the system will stay locked up.
1068 config BOOTPARAM_HARDLOCKUP_PANIC
1069 bool "Panic (Reboot) On Hard Lockups"
1070 depends on HARDLOCKUP_DETECTOR
1072 Say Y here to enable the kernel to panic on "hard lockups",
1073 which are bugs that cause the kernel to loop in kernel
1074 mode with interrupts disabled for more than 10 seconds (configurable
1075 using the watchdog_thresh sysctl).
1079 config DETECT_HUNG_TASK
1080 bool "Detect Hung Tasks"
1081 depends on DEBUG_KERNEL
1082 default SOFTLOCKUP_DETECTOR
1084 Say Y here to enable the kernel to detect "hung tasks",
1085 which are bugs that cause the task to be stuck in
1086 uninterruptible "D" state indefinitely.
1088 When a hung task is detected, the kernel will print the
1089 current stack trace (which you should report), but the
1090 task will stay in uninterruptible state. If lockdep is
1091 enabled then all held locks will also be reported. This
1092 feature has negligible overhead.
1094 config DEFAULT_HUNG_TASK_TIMEOUT
1095 int "Default timeout for hung task detection (in seconds)"
1096 depends on DETECT_HUNG_TASK
1099 This option controls the default timeout (in seconds) used
1100 to determine when a task has become non-responsive and should
1103 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1104 sysctl or by writing a value to
1105 /proc/sys/kernel/hung_task_timeout_secs.
1107 A timeout of 0 disables the check. The default is two minutes.
1108 Keeping the default should be fine in most cases.
1110 config BOOTPARAM_HUNG_TASK_PANIC
1111 bool "Panic (Reboot) On Hung Tasks"
1112 depends on DETECT_HUNG_TASK
1114 Say Y here to enable the kernel to panic on "hung tasks",
1115 which are bugs that cause the kernel to leave a task stuck
1116 in uninterruptible "D" state.
1118 The panic can be used in combination with panic_timeout,
1119 to cause the system to reboot automatically after a
1120 hung task has been detected. This feature is useful for
1121 high-availability systems that have uptime guarantees and
1122 where a hung tasks must be resolved ASAP.
1127 bool "Detect Workqueue Stalls"
1128 depends on DEBUG_KERNEL
1130 Say Y here to enable stall detection on workqueues. If a
1131 worker pool doesn't make forward progress on a pending work
1132 item for over a given amount of time, 30s by default, a
1133 warning message is printed along with dump of workqueue
1134 state. This can be configured through kernel parameter
1135 "workqueue.watchdog_thresh" and its sysfs counterpart.
1138 tristate "Test module to generate lockups"
1141 This builds the "test_lockup" module that helps to make sure
1142 that watchdogs and lockup detectors are working properly.
1144 Depending on module parameters it could emulate soft or hard
1145 lockup, "hung task", or locking arbitrary lock for a long time.
1146 Also it could generate series of lockups with cooling-down periods.
1150 endmenu # "Debug lockups and hangs"
1152 menu "Scheduler Debugging"
1155 bool "Collect scheduler debugging info"
1156 depends on DEBUG_KERNEL && DEBUG_FS
1159 If you say Y here, the /sys/kernel/debug/sched file will be provided
1160 that can help debug the scheduler. The runtime overhead of this
1168 bool "Collect scheduler statistics"
1169 depends on DEBUG_KERNEL && PROC_FS
1172 If you say Y here, additional code will be inserted into the
1173 scheduler and related routines to collect statistics about
1174 scheduler behavior and provide them in /proc/schedstat. These
1175 stats may be useful for both tuning and debugging the scheduler
1176 If you aren't debugging the scheduler or trying to tune a specific
1177 application, you can say N to avoid the very slight overhead
1182 config DEBUG_TIMEKEEPING
1183 bool "Enable extra timekeeping sanity checking"
1185 This option will enable additional timekeeping sanity checks
1186 which may be helpful when diagnosing issues where timekeeping
1187 problems are suspected.
1189 This may include checks in the timekeeping hotpaths, so this
1190 option may have a (very small) performance impact to some
1195 config DEBUG_PREEMPT
1196 bool "Debug preemptible kernel"
1197 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1199 If you say Y here then the kernel will use a debug variant of the
1200 commonly used smp_processor_id() function and will print warnings
1201 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1202 will detect preemption count underflows.
1204 This option has potential to introduce high runtime overhead,
1205 depending on workload as it triggers debugging routines for each
1206 this_cpu operation. It should only be used for debugging purposes.
1208 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1210 config LOCK_DEBUGGING_SUPPORT
1212 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1215 config PROVE_LOCKING
1216 bool "Lock debugging: prove locking correctness"
1217 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1219 select DEBUG_SPINLOCK
1220 select DEBUG_MUTEXES if !PREEMPT_RT
1221 select DEBUG_RT_MUTEXES if RT_MUTEXES
1223 select DEBUG_WW_MUTEX_SLOWPATH
1224 select DEBUG_LOCK_ALLOC
1225 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1226 select TRACE_IRQFLAGS
1229 This feature enables the kernel to prove that all locking
1230 that occurs in the kernel runtime is mathematically
1231 correct: that under no circumstance could an arbitrary (and
1232 not yet triggered) combination of observed locking
1233 sequences (on an arbitrary number of CPUs, running an
1234 arbitrary number of tasks and interrupt contexts) cause a
1237 In short, this feature enables the kernel to report locking
1238 related deadlocks before they actually occur.
1240 The proof does not depend on how hard and complex a
1241 deadlock scenario would be to trigger: how many
1242 participant CPUs, tasks and irq-contexts would be needed
1243 for it to trigger. The proof also does not depend on
1244 timing: if a race and a resulting deadlock is possible
1245 theoretically (no matter how unlikely the race scenario
1246 is), it will be proven so and will immediately be
1247 reported by the kernel (once the event is observed that
1248 makes the deadlock theoretically possible).
1250 If a deadlock is impossible (i.e. the locking rules, as
1251 observed by the kernel, are mathematically correct), the
1252 kernel reports nothing.
1254 NOTE: this feature can also be enabled for rwlocks, mutexes
1255 and rwsems - in which case all dependencies between these
1256 different locking variants are observed and mapped too, and
1257 the proof of observed correctness is also maintained for an
1258 arbitrary combination of these separate locking variants.
1260 For more details, see Documentation/locking/lockdep-design.rst.
1262 config PROVE_RAW_LOCK_NESTING
1263 bool "Enable raw_spinlock - spinlock nesting checks"
1264 depends on PROVE_LOCKING
1267 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1268 that the lock nesting rules for PREEMPT_RT enabled kernels are
1271 NOTE: There are known nesting problems. So if you enable this
1272 option expect lockdep splats until these problems have been fully
1273 addressed which is work in progress. This config switch allows to
1274 identify and analyze these problems. It will be removed and the
1275 check permanently enabled once the main issues have been fixed.
1277 If unsure, select N.
1280 bool "Lock usage statistics"
1281 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1283 select DEBUG_SPINLOCK
1284 select DEBUG_MUTEXES if !PREEMPT_RT
1285 select DEBUG_RT_MUTEXES if RT_MUTEXES
1286 select DEBUG_LOCK_ALLOC
1289 This feature enables tracking lock contention points
1291 For more details, see Documentation/locking/lockstat.rst
1293 This also enables lock events required by "perf lock",
1295 If you want to use "perf lock", you also need to turn on
1296 CONFIG_EVENT_TRACING.
1298 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1299 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1301 config DEBUG_RT_MUTEXES
1302 bool "RT Mutex debugging, deadlock detection"
1303 depends on DEBUG_KERNEL && RT_MUTEXES
1305 This allows rt mutex semantics violations and rt mutex related
1306 deadlocks (lockups) to be detected and reported automatically.
1308 config DEBUG_SPINLOCK
1309 bool "Spinlock and rw-lock debugging: basic checks"
1310 depends on DEBUG_KERNEL
1311 select UNINLINE_SPIN_UNLOCK
1313 Say Y here and build SMP to catch missing spinlock initialization
1314 and certain other kinds of spinlock errors commonly made. This is
1315 best used in conjunction with the NMI watchdog so that spinlock
1316 deadlocks are also debuggable.
1318 config DEBUG_MUTEXES
1319 bool "Mutex debugging: basic checks"
1320 depends on DEBUG_KERNEL && !PREEMPT_RT
1322 This feature allows mutex semantics violations to be detected and
1325 config DEBUG_WW_MUTEX_SLOWPATH
1326 bool "Wait/wound mutex debugging: Slowpath testing"
1327 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1328 select DEBUG_LOCK_ALLOC
1329 select DEBUG_SPINLOCK
1330 select DEBUG_MUTEXES if !PREEMPT_RT
1331 select DEBUG_RT_MUTEXES if PREEMPT_RT
1333 This feature enables slowpath testing for w/w mutex users by
1334 injecting additional -EDEADLK wound/backoff cases. Together with
1335 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1336 will test all possible w/w mutex interface abuse with the
1337 exception of simply not acquiring all the required locks.
1338 Note that this feature can introduce significant overhead, so
1339 it really should not be enabled in a production or distro kernel,
1340 even a debug kernel. If you are a driver writer, enable it. If
1341 you are a distro, do not.
1344 bool "RW Semaphore debugging: basic checks"
1345 depends on DEBUG_KERNEL
1347 This debugging feature allows mismatched rw semaphore locks
1348 and unlocks to be detected and reported.
1350 config DEBUG_LOCK_ALLOC
1351 bool "Lock debugging: detect incorrect freeing of live locks"
1352 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1353 select DEBUG_SPINLOCK
1354 select DEBUG_MUTEXES if !PREEMPT_RT
1355 select DEBUG_RT_MUTEXES if RT_MUTEXES
1358 This feature will check whether any held lock (spinlock, rwlock,
1359 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1360 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1361 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1362 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1363 held during task exit.
1367 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1372 config LOCKDEP_SMALL
1376 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1377 depends on LOCKDEP && !LOCKDEP_SMALL
1381 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1383 config LOCKDEP_CHAINS_BITS
1384 int "Bitsize for MAX_LOCKDEP_CHAINS"
1385 depends on LOCKDEP && !LOCKDEP_SMALL
1389 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1391 config LOCKDEP_STACK_TRACE_BITS
1392 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1393 depends on LOCKDEP && !LOCKDEP_SMALL
1397 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1399 config LOCKDEP_STACK_TRACE_HASH_BITS
1400 int "Bitsize for STACK_TRACE_HASH_SIZE"
1401 depends on LOCKDEP && !LOCKDEP_SMALL
1405 Try increasing this value if you need large STACK_TRACE_HASH_SIZE.
1407 config LOCKDEP_CIRCULAR_QUEUE_BITS
1408 int "Bitsize for elements in circular_queue struct"
1413 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1415 config DEBUG_LOCKDEP
1416 bool "Lock dependency engine debugging"
1417 depends on DEBUG_KERNEL && LOCKDEP
1418 select DEBUG_IRQFLAGS
1420 If you say Y here, the lock dependency engine will do
1421 additional runtime checks to debug itself, at the price
1422 of more runtime overhead.
1424 config DEBUG_ATOMIC_SLEEP
1425 bool "Sleep inside atomic section checking"
1426 select PREEMPT_COUNT
1427 depends on DEBUG_KERNEL
1428 depends on !ARCH_NO_PREEMPT
1430 If you say Y here, various routines which may sleep will become very
1431 noisy if they are called inside atomic sections: when a spinlock is
1432 held, inside an rcu read side critical section, inside preempt disabled
1433 sections, inside an interrupt, etc...
1435 config DEBUG_LOCKING_API_SELFTESTS
1436 bool "Locking API boot-time self-tests"
1437 depends on DEBUG_KERNEL
1439 Say Y here if you want the kernel to run a short self-test during
1440 bootup. The self-test checks whether common types of locking bugs
1441 are detected by debugging mechanisms or not. (if you disable
1442 lock debugging then those bugs won't be detected of course.)
1443 The following locking APIs are covered: spinlocks, rwlocks,
1446 config LOCK_TORTURE_TEST
1447 tristate "torture tests for locking"
1448 depends on DEBUG_KERNEL
1451 This option provides a kernel module that runs torture tests
1452 on kernel locking primitives. The kernel module may be built
1453 after the fact on the running kernel to be tested, if desired.
1455 Say Y here if you want kernel locking-primitive torture tests
1456 to be built into the kernel.
1457 Say M if you want these torture tests to build as a module.
1458 Say N if you are unsure.
1460 config WW_MUTEX_SELFTEST
1461 tristate "Wait/wound mutex selftests"
1463 This option provides a kernel module that runs tests on the
1464 on the struct ww_mutex locking API.
1466 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1467 with this test harness.
1469 Say M if you want these self tests to build as a module.
1470 Say N if you are unsure.
1472 config SCF_TORTURE_TEST
1473 tristate "torture tests for smp_call_function*()"
1474 depends on DEBUG_KERNEL
1477 This option provides a kernel module that runs torture tests
1478 on the smp_call_function() family of primitives. The kernel
1479 module may be built after the fact on the running kernel to
1480 be tested, if desired.
1482 config CSD_LOCK_WAIT_DEBUG
1483 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1484 depends on DEBUG_KERNEL
1488 This option enables debug prints when CPUs are slow to respond
1489 to the smp_call_function*() IPI wrappers. These debug prints
1490 include the IPI handler function currently executing (if any)
1491 and relevant stack traces.
1493 config CSD_LOCK_WAIT_DEBUG_DEFAULT
1494 bool "Default csd_lock_wait() debugging on at boot time"
1495 depends on CSD_LOCK_WAIT_DEBUG
1499 This option causes the csdlock_debug= kernel boot parameter to
1500 default to 1 (basic debugging) instead of 0 (no debugging).
1502 endmenu # lock debugging
1504 config TRACE_IRQFLAGS
1505 depends on TRACE_IRQFLAGS_SUPPORT
1508 Enables hooks to interrupt enabling and disabling for
1509 either tracing or lock debugging.
1511 config TRACE_IRQFLAGS_NMI
1513 depends on TRACE_IRQFLAGS
1514 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1516 config NMI_CHECK_CPU
1517 bool "Debugging for CPUs failing to respond to backtrace requests"
1518 depends on DEBUG_KERNEL
1522 Enables debug prints when a CPU fails to respond to a given
1523 backtrace NMI. These prints provide some reasons why a CPU
1524 might legitimately be failing to respond, for example, if it
1525 is offline of if ignore_nmis is set.
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 config DEBUG_CGROUP_REF
1720 bool "Disable inlining of cgroup css reference count functions"
1721 depends on DEBUG_KERNEL
1726 Force cgroup css reference count functions to not be inlined so
1727 that they can be kprobed for debugging.
1729 source "kernel/trace/Kconfig"
1731 config PROVIDE_OHCI1394_DMA_INIT
1732 bool "Remote debugging over FireWire early on boot"
1733 depends on PCI && X86
1735 If you want to debug problems which hang or crash the kernel early
1736 on boot and the crashing machine has a FireWire port, you can use
1737 this feature to remotely access the memory of the crashed machine
1738 over FireWire. This employs remote DMA as part of the OHCI1394
1739 specification which is now the standard for FireWire controllers.
1741 With remote DMA, you can monitor the printk buffer remotely using
1742 firescope and access all memory below 4GB using fireproxy from gdb.
1743 Even controlling a kernel debugger is possible using remote DMA.
1747 If ohci1394_dma=early is used as boot parameter, it will initialize
1748 all OHCI1394 controllers which are found in the PCI config space.
1750 As all changes to the FireWire bus such as enabling and disabling
1751 devices cause a bus reset and thereby disable remote DMA for all
1752 devices, be sure to have the cable plugged and FireWire enabled on
1753 the debugging host before booting the debug target for debugging.
1755 This code (~1k) is freed after boot. By then, the firewire stack
1756 in charge of the OHCI-1394 controllers should be used instead.
1758 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1760 source "samples/Kconfig"
1762 config ARCH_HAS_DEVMEM_IS_ALLOWED
1765 config STRICT_DEVMEM
1766 bool "Filter access to /dev/mem"
1767 depends on MMU && DEVMEM
1768 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1769 default y if PPC || X86 || ARM64
1771 If this option is disabled, you allow userspace (root) access to all
1772 of memory, including kernel and userspace memory. Accidental
1773 access to this is obviously disastrous, but specific access can
1774 be used by people debugging the kernel. Note that with PAT support
1775 enabled, even in this case there are restrictions on /dev/mem
1776 use due to the cache aliasing requirements.
1778 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1779 file only allows userspace access to PCI space and the BIOS code and
1780 data regions. This is sufficient for dosemu and X and all common
1785 config IO_STRICT_DEVMEM
1786 bool "Filter I/O access to /dev/mem"
1787 depends on STRICT_DEVMEM
1789 If this option is disabled, you allow userspace (root) access to all
1790 io-memory regardless of whether a driver is actively using that
1791 range. Accidental access to this is obviously disastrous, but
1792 specific access can be used by people debugging kernel drivers.
1794 If this option is switched on, the /dev/mem file only allows
1795 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1796 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1797 if the driver using a given range cannot be disabled.
1801 menu "$(SRCARCH) Debugging"
1803 source "arch/$(SRCARCH)/Kconfig.debug"
1807 menu "Kernel Testing and Coverage"
1809 source "lib/kunit/Kconfig"
1811 config NOTIFIER_ERROR_INJECTION
1812 tristate "Notifier error injection"
1813 depends on DEBUG_KERNEL
1816 This option provides the ability to inject artificial errors to
1817 specified notifier chain callbacks. It is useful to test the error
1818 handling of notifier call chain failures.
1822 config PM_NOTIFIER_ERROR_INJECT
1823 tristate "PM notifier error injection module"
1824 depends on PM && NOTIFIER_ERROR_INJECTION
1825 default m if PM_DEBUG
1827 This option provides the ability to inject artificial errors to
1828 PM notifier chain callbacks. It is controlled through debugfs
1829 interface /sys/kernel/debug/notifier-error-inject/pm
1831 If the notifier call chain should be failed with some events
1832 notified, write the error code to "actions/<notifier event>/error".
1834 Example: Inject PM suspend error (-12 = -ENOMEM)
1836 # cd /sys/kernel/debug/notifier-error-inject/pm/
1837 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1838 # echo mem > /sys/power/state
1839 bash: echo: write error: Cannot allocate memory
1841 To compile this code as a module, choose M here: the module will
1842 be called pm-notifier-error-inject.
1846 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1847 tristate "OF reconfig notifier error injection module"
1848 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1850 This option provides the ability to inject artificial errors to
1851 OF reconfig notifier chain callbacks. It is controlled
1852 through debugfs interface under
1853 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1855 If the notifier call chain should be failed with some events
1856 notified, write the error code to "actions/<notifier event>/error".
1858 To compile this code as a module, choose M here: the module will
1859 be called of-reconfig-notifier-error-inject.
1863 config NETDEV_NOTIFIER_ERROR_INJECT
1864 tristate "Netdev notifier error injection module"
1865 depends on NET && NOTIFIER_ERROR_INJECTION
1867 This option provides the ability to inject artificial errors to
1868 netdevice notifier chain callbacks. It is controlled through debugfs
1869 interface /sys/kernel/debug/notifier-error-inject/netdev
1871 If the notifier call chain should be failed with some events
1872 notified, write the error code to "actions/<notifier event>/error".
1874 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1876 # cd /sys/kernel/debug/notifier-error-inject/netdev
1877 # echo -22 > actions/NETDEV_CHANGEMTU/error
1878 # ip link set eth0 mtu 1024
1879 RTNETLINK answers: Invalid argument
1881 To compile this code as a module, choose M here: the module will
1882 be called netdev-notifier-error-inject.
1886 config FUNCTION_ERROR_INJECTION
1887 bool "Fault-injections of functions"
1888 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1890 Add fault injections into various functions that are annotated with
1891 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
1892 value of these functions. This is useful to test error paths of code.
1896 config FAULT_INJECTION
1897 bool "Fault-injection framework"
1898 depends on DEBUG_KERNEL
1900 Provide fault-injection framework.
1901 For more details, see Documentation/fault-injection/.
1904 bool "Fault-injection capability for kmalloc"
1905 depends on FAULT_INJECTION
1906 depends on SLAB || SLUB
1908 Provide fault-injection capability for kmalloc.
1910 config FAIL_PAGE_ALLOC
1911 bool "Fault-injection capability for alloc_pages()"
1912 depends on FAULT_INJECTION
1914 Provide fault-injection capability for alloc_pages().
1916 config FAULT_INJECTION_USERCOPY
1917 bool "Fault injection capability for usercopy functions"
1918 depends on FAULT_INJECTION
1920 Provides fault-injection capability to inject failures
1921 in usercopy functions (copy_from_user(), get_user(), ...).
1923 config FAIL_MAKE_REQUEST
1924 bool "Fault-injection capability for disk IO"
1925 depends on FAULT_INJECTION && BLOCK
1927 Provide fault-injection capability for disk IO.
1929 config FAIL_IO_TIMEOUT
1930 bool "Fault-injection capability for faking disk interrupts"
1931 depends on FAULT_INJECTION && BLOCK
1933 Provide fault-injection capability on end IO handling. This
1934 will make the block layer "forget" an interrupt as configured,
1935 thus exercising the error handling.
1937 Only works with drivers that use the generic timeout handling,
1938 for others it won't do anything.
1941 bool "Fault-injection capability for futexes"
1943 depends on FAULT_INJECTION && FUTEX
1945 Provide fault-injection capability for futexes.
1947 config FAULT_INJECTION_DEBUG_FS
1948 bool "Debugfs entries for fault-injection capabilities"
1949 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1951 Enable configuration of fault-injection capabilities via debugfs.
1953 config FAIL_FUNCTION
1954 bool "Fault-injection capability for functions"
1955 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1957 Provide function-based fault-injection capability.
1958 This will allow you to override a specific function with a return
1959 with given return value. As a result, function caller will see
1960 an error value and have to handle it. This is useful to test the
1961 error handling in various subsystems.
1963 config FAIL_MMC_REQUEST
1964 bool "Fault-injection capability for MMC IO"
1965 depends on FAULT_INJECTION_DEBUG_FS && MMC
1967 Provide fault-injection capability for MMC IO.
1968 This will make the mmc core return data errors. This is
1969 useful to test the error handling in the mmc block device
1970 and to test how the mmc host driver handles retries from
1974 bool "Fault-injection capability for SunRPC"
1975 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1977 Provide fault-injection capability for SunRPC and
1980 config FAULT_INJECTION_CONFIGFS
1981 bool "Configfs interface for fault-injection capabilities"
1982 depends on FAULT_INJECTION
1985 This option allows configfs-based drivers to dynamically configure
1986 fault-injection via configfs. Each parameter for driver-specific
1987 fault-injection can be made visible as a configfs attribute in a
1991 config FAULT_INJECTION_STACKTRACE_FILTER
1992 bool "stacktrace filter for fault-injection capabilities"
1993 depends on FAULT_INJECTION
1994 depends on (FAULT_INJECTION_DEBUG_FS || FAULT_INJECTION_CONFIGFS) && STACKTRACE_SUPPORT
1996 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1998 Provide stacktrace filter for fault-injection capabilities
2000 config ARCH_HAS_KCOV
2003 An architecture should select this when it can successfully
2004 build and run with CONFIG_KCOV. This typically requires
2005 disabling instrumentation for some early boot code.
2007 config CC_HAS_SANCOV_TRACE_PC
2008 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2012 bool "Code coverage for fuzzing"
2013 depends on ARCH_HAS_KCOV
2014 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2015 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2016 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
2018 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2019 select OBJTOOL if HAVE_NOINSTR_HACK
2021 KCOV exposes kernel code coverage information in a form suitable
2022 for coverage-guided fuzzing (randomized testing).
2024 If RANDOMIZE_BASE is enabled, PC values will not be stable across
2025 different machines and across reboots. If you need stable PC values,
2026 disable RANDOMIZE_BASE.
2028 For more details, see Documentation/dev-tools/kcov.rst.
2030 config KCOV_ENABLE_COMPARISONS
2031 bool "Enable comparison operands collection by KCOV"
2033 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2035 KCOV also exposes operands of every comparison in the instrumented
2036 code along with operand sizes and PCs of the comparison instructions.
2037 These operands can be used by fuzzing engines to improve the quality
2038 of fuzzing coverage.
2040 config KCOV_INSTRUMENT_ALL
2041 bool "Instrument all code by default"
2045 If you are doing generic system call fuzzing (like e.g. syzkaller),
2046 then you will want to instrument the whole kernel and you should
2047 say y here. If you are doing more targeted fuzzing (like e.g.
2048 filesystem fuzzing with AFL) then you will want to enable coverage
2049 for more specific subsets of files, and should say n here.
2051 config KCOV_IRQ_AREA_SIZE
2052 hex "Size of interrupt coverage collection area in words"
2056 KCOV uses preallocated per-cpu areas to collect coverage from
2057 soft interrupts. This specifies the size of those areas in the
2058 number of unsigned long words.
2060 menuconfig RUNTIME_TESTING_MENU
2061 bool "Runtime Testing"
2064 if RUNTIME_TESTING_MENU
2067 tristate "Dhrystone benchmark test"
2069 Enable this to include the Dhrystone 2.1 benchmark. This test
2070 calculates the number of Dhrystones per second, and the number of
2071 DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided
2072 by 1757 (the number of Dhrystones per second obtained on the VAX
2073 11/780, nominally a 1 MIPS machine).
2075 To run the benchmark, it needs to be enabled explicitly, either from
2076 the kernel command line (when built-in), or from userspace (when
2077 built-in or modular.
2079 Run once during kernel boot:
2083 Set number of iterations from kernel command line:
2085 test_dhry.iterations=<n>
2087 Set number of iterations from userspace:
2089 echo <n> > /sys/module/test_dhry/parameters/iterations
2091 Trigger manual run from userspace:
2093 echo y > /sys/module/test_dhry/parameters/run
2095 If the number of iterations is <= 0, the test will devise a suitable
2096 number of iterations (test runs for at least 2s) automatically.
2097 This process takes ca. 4s.
2102 tristate "Linux Kernel Dump Test Tool Module"
2105 This module enables testing of the different dumping mechanisms by
2106 inducing system failures at predefined crash points.
2107 If you don't need it: say N
2108 Choose M here to compile this code as a module. The module will be
2111 Documentation on how to use the module can be found in
2112 Documentation/fault-injection/provoke-crashes.rst
2114 config CPUMASK_KUNIT_TEST
2115 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2117 default KUNIT_ALL_TESTS
2119 Enable to turn on cpumask tests, running at boot or module load time.
2121 For more information on KUnit and unit tests in general, please refer
2122 to the KUnit documentation in Documentation/dev-tools/kunit/.
2126 config TEST_LIST_SORT
2127 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2129 default KUNIT_ALL_TESTS
2131 Enable this to turn on 'list_sort()' function test. This test is
2132 executed only once during system boot (so affects only boot time),
2133 or at module load time.
2137 config TEST_MIN_HEAP
2138 tristate "Min heap test"
2139 depends on DEBUG_KERNEL || m
2141 Enable this to turn on min heap function tests. This test is
2142 executed only once during system boot (so affects only boot time),
2143 or at module load time.
2148 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2150 default KUNIT_ALL_TESTS
2152 This option enables the self-test function of 'sort()' at boot,
2153 or at module load time.
2158 tristate "64bit/32bit division and modulo test"
2159 depends on DEBUG_KERNEL || m
2161 Enable this to turn on 'do_div()' function test. This test is
2162 executed only once during system boot (so affects only boot time),
2163 or at module load time.
2167 config KPROBES_SANITY_TEST
2168 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2169 depends on DEBUG_KERNEL
2172 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2173 default KUNIT_ALL_TESTS
2175 This option provides for testing basic kprobes functionality on
2176 boot. Samples of kprobe and kretprobe are inserted and
2177 verified for functionality.
2179 Say N if you are unsure.
2181 config FPROBE_SANITY_TEST
2182 bool "Self test for fprobe"
2183 depends on DEBUG_KERNEL
2187 This option will enable testing the fprobe when the system boot.
2188 A series of tests are made to verify that the fprobe is functioning
2191 Say N if you are unsure.
2193 config BACKTRACE_SELF_TEST
2194 tristate "Self test for the backtrace code"
2195 depends on DEBUG_KERNEL
2197 This option provides a kernel module that can be used to test
2198 the kernel stack backtrace code. This option is not useful
2199 for distributions or general kernels, but only for kernel
2200 developers working on architecture code.
2202 Note that if you want to also test saved backtraces, you will
2203 have to enable STACKTRACE as well.
2205 Say N if you are unsure.
2207 config TEST_REF_TRACKER
2208 tristate "Self test for reference tracker"
2209 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2212 This option provides a kernel module performing tests
2213 using reference tracker infrastructure.
2215 Say N if you are unsure.
2218 tristate "Red-Black tree test"
2219 depends on DEBUG_KERNEL
2221 A benchmark measuring the performance of the rbtree library.
2222 Also includes rbtree invariant checks.
2224 config REED_SOLOMON_TEST
2225 tristate "Reed-Solomon library test"
2226 depends on DEBUG_KERNEL || m
2228 select REED_SOLOMON_ENC16
2229 select REED_SOLOMON_DEC16
2231 This option enables the self-test function of rslib at boot,
2232 or at module load time.
2236 config INTERVAL_TREE_TEST
2237 tristate "Interval tree test"
2238 depends on DEBUG_KERNEL
2239 select INTERVAL_TREE
2241 A benchmark measuring the performance of the interval tree library
2244 tristate "Per cpu operations test"
2245 depends on m && DEBUG_KERNEL
2247 Enable this option to build test module which validates per-cpu
2252 config ATOMIC64_SELFTEST
2253 tristate "Perform an atomic64_t self-test"
2255 Enable this option to test the atomic64_t functions at boot or
2256 at module load time.
2260 config ASYNC_RAID6_TEST
2261 tristate "Self test for hardware accelerated raid6 recovery"
2262 depends on ASYNC_RAID6_RECOV
2265 This is a one-shot self test that permutes through the
2266 recovery of all the possible two disk failure scenarios for a
2267 N-disk array. Recovery is performed with the asynchronous
2268 raid6 recovery routines, and will optionally use an offload
2269 engine if one is available.
2274 tristate "Test functions located in the hexdump module at runtime"
2276 config STRING_SELFTEST
2277 tristate "Test string functions at runtime"
2279 config TEST_STRING_HELPERS
2280 tristate "Test functions located in the string_helpers module at runtime"
2283 tristate "Test kstrto*() family of functions at runtime"
2286 tristate "Test printf() family of functions at runtime"
2289 tristate "Test scanf() family of functions at runtime"
2292 tristate "Test bitmap_*() family of functions at runtime"
2294 Enable this option to test the bitmap functions at boot.
2299 tristate "Test functions located in the uuid module at runtime"
2302 tristate "Test the XArray code at runtime"
2304 config TEST_MAPLE_TREE
2305 depends on DEBUG_KERNEL
2306 select DEBUG_MAPLE_TREE
2307 tristate "Test the Maple Tree code at runtime"
2309 config TEST_RHASHTABLE
2310 tristate "Perform selftest on resizable hash table"
2312 Enable this option to test the rhashtable functions at boot.
2317 tristate "Perform selftest on IDA functions"
2320 tristate "Perform selftest on priority array manager"
2323 Enable this option to test priority array manager on boot
2328 config TEST_IRQ_TIMINGS
2329 bool "IRQ timings selftest"
2330 depends on IRQ_TIMINGS
2332 Enable this option to test the irq timings code on boot.
2337 tristate "Test module loading with 'hello world' module"
2340 This builds the "test_module" module that emits "Hello, world"
2341 on printk when loaded. It is designed to be used for basic
2342 evaluation of the module loading subsystem (for example when
2343 validating module verification). It lacks any extra dependencies,
2344 and will not normally be loaded by the system unless explicitly
2350 tristate "Test module for compilation of bitops operations"
2353 This builds the "test_bitops" module that is much like the
2354 TEST_LKM module except that it does a basic exercise of the
2355 set/clear_bit macros and get_count_order/long to make sure there are
2356 no compiler warnings from C=1 sparse checker or -Wextra
2357 compilations. It has no dependencies and doesn't run or load unless
2358 explicitly requested by name. for example: modprobe test_bitops.
2363 tristate "Test module for stress/performance analysis of vmalloc allocator"
2368 This builds the "test_vmalloc" module that should be used for
2369 stress and performance analysis. So, any new change for vmalloc
2370 subsystem can be evaluated from performance and stability point
2375 config TEST_USER_COPY
2376 tristate "Test user/kernel boundary protections"
2379 This builds the "test_user_copy" module that runs sanity checks
2380 on the copy_to/from_user infrastructure, making sure basic
2381 user/kernel boundary testing is working. If it fails to load,
2382 a regression has been detected in the user/kernel memory boundary
2388 tristate "Test BPF filter functionality"
2391 This builds the "test_bpf" module that runs various test vectors
2392 against the BPF interpreter or BPF JIT compiler depending on the
2393 current setting. This is in particular useful for BPF JIT compiler
2394 development, but also to run regression tests against changes in
2395 the interpreter code. It also enables test stubs for eBPF maps and
2396 verifier used by user space verifier testsuite.
2400 config TEST_BLACKHOLE_DEV
2401 tristate "Test blackhole netdev functionality"
2404 This builds the "test_blackhole_dev" module that validates the
2405 data path through this blackhole netdev.
2409 config FIND_BIT_BENCHMARK
2410 tristate "Test find_bit functions"
2412 This builds the "test_find_bit" module that measure find_*_bit()
2413 functions performance.
2417 config TEST_FIRMWARE
2418 tristate "Test firmware loading via userspace interface"
2419 depends on FW_LOADER
2421 This builds the "test_firmware" module that creates a userspace
2422 interface for testing firmware loading. This can be used to
2423 control the triggering of firmware loading without needing an
2424 actual firmware-using device. The contents can be rechecked by
2430 tristate "sysctl test driver"
2431 depends on PROC_SYSCTL
2433 This builds the "test_sysctl" module. This driver enables to test the
2434 proc sysctl interfaces available to drivers safely without affecting
2435 production knobs which might alter system functionality.
2439 config BITFIELD_KUNIT
2440 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2442 default KUNIT_ALL_TESTS
2444 Enable this option to test the bitfield functions at boot.
2446 KUnit tests run during boot and output the results to the debug log
2447 in TAP format (http://testanything.org/). Only useful for kernel devs
2448 running the KUnit test harness, and not intended for inclusion into a
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 HASH_KUNIT_TEST
2457 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2459 default KUNIT_ALL_TESTS
2461 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2462 integer (<linux/hash.h>) hash functions on boot.
2464 KUnit tests run during boot and output the results to the debug log
2465 in TAP format (https://testanything.org/). Only useful for kernel devs
2466 running the KUnit test harness, and not intended for inclusion into a
2469 For more information on KUnit and unit tests in general please refer
2470 to the KUnit documentation in Documentation/dev-tools/kunit/.
2472 This is intended to help people writing architecture-specific
2473 optimized versions. If unsure, say N.
2475 config RESOURCE_KUNIT_TEST
2476 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2478 default KUNIT_ALL_TESTS
2480 This builds the resource API unit test.
2481 Tests the logic of API provided by resource.c and ioport.h.
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 SYSCTL_KUNIT_TEST
2488 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2490 default KUNIT_ALL_TESTS
2492 This builds the proc sysctl unit test, which runs on boot.
2493 Tests the API contract and implementation correctness of sysctl.
2494 For more information on KUnit and unit tests in general please refer
2495 to the KUnit documentation in Documentation/dev-tools/kunit/.
2499 config LIST_KUNIT_TEST
2500 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2502 default KUNIT_ALL_TESTS
2504 This builds the linked list KUnit test suite.
2505 It tests that the API and basic functionality of the list_head type
2506 and associated macros.
2508 KUnit tests run during boot and output the results to the debug log
2509 in TAP format (https://testanything.org/). Only useful for kernel devs
2510 running the KUnit test harness, and not intended for inclusion into a
2513 For more information on KUnit and unit tests in general please refer
2514 to the KUnit documentation in Documentation/dev-tools/kunit/.
2518 config HASHTABLE_KUNIT_TEST
2519 tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS
2521 default KUNIT_ALL_TESTS
2523 This builds the hashtable KUnit test suite.
2524 It tests the basic functionality of the API defined in
2525 include/linux/hashtable.h. For more information on KUnit and
2526 unit tests in general please refer to the KUnit documentation
2527 in Documentation/dev-tools/kunit/.
2531 config LINEAR_RANGES_TEST
2532 tristate "KUnit test for linear_ranges"
2534 select LINEAR_RANGES
2536 This builds the linear_ranges unit test, which runs on boot.
2537 Tests the linear_ranges logic correctness.
2538 For more information on KUnit and unit tests in general please refer
2539 to the KUnit documentation in Documentation/dev-tools/kunit/.
2543 config CMDLINE_KUNIT_TEST
2544 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2546 default KUNIT_ALL_TESTS
2548 This builds the cmdline API unit test.
2549 Tests the logic of API provided by cmdline.c.
2550 For more information on KUnit and unit tests in general please refer
2551 to the KUnit documentation in Documentation/dev-tools/kunit/.
2556 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2558 default KUNIT_ALL_TESTS
2560 This builds the bits unit test.
2561 Tests the logic of macros defined in bits.h.
2562 For more information on KUnit and unit tests in general please refer
2563 to the KUnit documentation in Documentation/dev-tools/kunit/.
2567 config SLUB_KUNIT_TEST
2568 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2569 depends on SLUB_DEBUG && KUNIT
2570 default KUNIT_ALL_TESTS
2572 This builds SLUB allocator unit test.
2573 Tests SLUB cache debugging functionality.
2574 For more information on KUnit and unit tests in general please refer
2575 to the KUnit documentation in Documentation/dev-tools/kunit/.
2579 config RATIONAL_KUNIT_TEST
2580 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2581 depends on KUNIT && RATIONAL
2582 default KUNIT_ALL_TESTS
2584 This builds the rational math unit test.
2585 For more information on KUnit and unit tests in general please refer
2586 to the KUnit documentation in Documentation/dev-tools/kunit/.
2590 config MEMCPY_KUNIT_TEST
2591 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2593 default KUNIT_ALL_TESTS
2595 Builds unit tests for memcpy(), memmove(), and memset() functions.
2596 For more information on KUnit and unit tests in general please refer
2597 to the KUnit documentation in Documentation/dev-tools/kunit/.
2601 config MEMCPY_SLOW_KUNIT_TEST
2602 bool "Include exhaustive memcpy tests"
2603 depends on MEMCPY_KUNIT_TEST
2606 Some memcpy tests are quite exhaustive in checking for overlaps
2607 and bit ranges. These can be very slow, so they are split out
2608 as a separate config, in case they need to be disabled.
2610 config IS_SIGNED_TYPE_KUNIT_TEST
2611 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2613 default KUNIT_ALL_TESTS
2615 Builds unit tests for the is_signed_type() macro.
2617 For more information on KUnit and unit tests in general please refer
2618 to the KUnit documentation in Documentation/dev-tools/kunit/.
2622 config OVERFLOW_KUNIT_TEST
2623 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2625 default KUNIT_ALL_TESTS
2627 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2630 For more information on KUnit and unit tests in general please refer
2631 to the KUnit documentation in Documentation/dev-tools/kunit/.
2635 config STACKINIT_KUNIT_TEST
2636 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2638 default KUNIT_ALL_TESTS
2640 Test if the kernel is zero-initializing stack variables and
2641 padding. Coverage is controlled by compiler flags,
2642 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2643 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2644 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2646 config FORTIFY_KUNIT_TEST
2647 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2648 depends on KUNIT && FORTIFY_SOURCE
2649 default KUNIT_ALL_TESTS
2651 Builds unit tests for checking internals of FORTIFY_SOURCE as used
2652 by the str*() and mem*() family of functions. For testing runtime
2653 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2655 config HW_BREAKPOINT_KUNIT_TEST
2656 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2657 depends on HAVE_HW_BREAKPOINT
2659 default KUNIT_ALL_TESTS
2661 Tests for hw_breakpoint constraints accounting.
2665 config STRSCPY_KUNIT_TEST
2666 tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS
2668 default KUNIT_ALL_TESTS
2670 config SIPHASH_KUNIT_TEST
2671 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2673 default KUNIT_ALL_TESTS
2675 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2676 functions on boot (or module load).
2678 This is intended to help people writing architecture-specific
2679 optimized versions. If unsure, say N.
2682 tristate "udelay test driver"
2684 This builds the "udelay_test" module that helps to make sure
2685 that udelay() is working properly.
2689 config TEST_STATIC_KEYS
2690 tristate "Test static keys"
2693 Test the static key interfaces.
2697 config TEST_DYNAMIC_DEBUG
2698 tristate "Test DYNAMIC_DEBUG"
2699 depends on DYNAMIC_DEBUG
2701 This module registers a tracer callback to count enabled
2702 pr_debugs in a 'do_debugging' function, then alters their
2703 enablements, calls the function, and compares counts.
2708 tristate "kmod stress tester"
2710 depends on NETDEVICES && NET_CORE && INET # for TUN
2712 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2718 Test the kernel's module loading mechanism: kmod. kmod implements
2719 support to load modules using the Linux kernel's usermode helper.
2720 This test provides a series of tests against kmod.
2722 Although technically you can either build test_kmod as a module or
2723 into the kernel we disallow building it into the kernel since
2724 it stress tests request_module() and this will very likely cause
2725 some issues by taking over precious threads available from other
2726 module load requests, ultimately this could be fatal.
2730 tools/testing/selftests/kmod/kmod.sh --help
2734 config TEST_DEBUG_VIRTUAL
2735 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2736 depends on DEBUG_VIRTUAL
2738 Test the kernel's ability to detect incorrect calls to
2739 virt_to_phys() done against the non-linear part of the
2740 kernel's virtual address map.
2744 config TEST_MEMCAT_P
2745 tristate "Test memcat_p() helper function"
2747 Test the memcat_p() helper for correctly merging two
2748 pointer arrays together.
2752 config TEST_LIVEPATCH
2753 tristate "Test livepatching"
2755 depends on DYNAMIC_DEBUG
2756 depends on LIVEPATCH
2759 Test kernel livepatching features for correctness. The tests will
2760 load test modules that will be livepatched in various scenarios.
2762 To run all the livepatching tests:
2764 make -C tools/testing/selftests TARGETS=livepatch run_tests
2766 Alternatively, individual tests may be invoked:
2768 tools/testing/selftests/livepatch/test-callbacks.sh
2769 tools/testing/selftests/livepatch/test-livepatch.sh
2770 tools/testing/selftests/livepatch/test-shadow-vars.sh
2775 tristate "Perform selftest on object aggreration manager"
2779 Enable this option to test object aggregation manager on boot
2783 tristate "Test heap/page initialization"
2785 Test if the kernel is zero-initializing heap and page allocations.
2786 This can be useful to test init_on_alloc and init_on_free features.
2791 tristate "Test HMM (Heterogeneous Memory Management)"
2792 depends on TRANSPARENT_HUGEPAGE
2793 depends on DEVICE_PRIVATE
2797 This is a pseudo device driver solely for testing HMM.
2798 Say M here if you want to build the HMM test module.
2799 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2803 config TEST_FREE_PAGES
2804 tristate "Test freeing pages"
2806 Test that a memory leak does not occur due to a race between
2807 freeing a block of pages and a speculative page reference.
2808 Loading this module is safe if your kernel has the bug fixed.
2809 If the bug is not fixed, it will leak gigabytes of memory and
2810 probably OOM your system.
2813 tristate "Test floating point operations in kernel space"
2814 depends on X86 && !KCOV_INSTRUMENT_ALL
2816 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2817 which will trigger a sequence of floating point operations. This is used
2818 for self-testing floating point control register setting in
2823 config TEST_CLOCKSOURCE_WATCHDOG
2824 tristate "Test clocksource watchdog in kernel space"
2825 depends on CLOCKSOURCE_WATCHDOG
2827 Enable this option to create a kernel module that will trigger
2828 a test of the clocksource watchdog. This module may be loaded
2829 via modprobe or insmod in which case it will run upon being
2830 loaded, or it may be built in, in which case it will run
2835 endif # RUNTIME_TESTING_MENU
2837 config ARCH_USE_MEMTEST
2840 An architecture should select this when it uses early_memtest()
2841 during boot process.
2845 depends on ARCH_USE_MEMTEST
2847 This option adds a kernel parameter 'memtest', which allows memtest
2848 to be set and executed.
2849 memtest=0, mean disabled; -- default
2850 memtest=1, mean do 1 test pattern;
2852 memtest=17, mean do 17 test patterns.
2853 If you are unsure how to answer this question, answer N.
2857 config HYPERV_TESTING
2858 bool "Microsoft Hyper-V driver testing"
2860 depends on HYPERV && DEBUG_FS
2862 Select this option to enable Hyper-V vmbus testing.
2864 endmenu # "Kernel Testing and Coverage"
2868 config RUST_DEBUG_ASSERTIONS
2869 bool "Debug assertions"
2872 Enables rustc's `-Cdebug-assertions` codegen option.
2874 This flag lets you turn `cfg(debug_assertions)` conditional
2875 compilation on or off. This can be used to enable extra debugging
2876 code in development but not in production. For example, it controls
2877 the behavior of the standard library's `debug_assert!` macro.
2879 Note that this will apply to all Rust code, including `core`.
2883 config RUST_OVERFLOW_CHECKS
2884 bool "Overflow checks"
2888 Enables rustc's `-Coverflow-checks` codegen option.
2890 This flag allows you to control the behavior of runtime integer
2891 overflow. When overflow-checks are enabled, a Rust panic will occur
2894 Note that this will apply to all Rust code, including `core`.
2898 config RUST_BUILD_ASSERT_ALLOW
2899 bool "Allow unoptimized build-time assertions"
2902 Controls how are `build_error!` and `build_assert!` handled during build.
2904 If calls to them exist in the binary, it may indicate a violated invariant
2905 or that the optimizer failed to verify the invariant during compilation.
2907 This should not happen, thus by default the build is aborted. However,
2908 as an escape hatch, you can choose Y here to ignore them during build
2909 and let the check be carried at runtime (with `panic!` being called if
2916 endmenu # Kernel hacking
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