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)
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_MAPLE_TREE
795 bool "Debug VM maple trees"
797 select DEBUG_MAPLE_TREE
799 Enable VM maple tree debugging information and extra validations.
804 bool "Debug VM red-black trees"
807 Enable VM red-black tree debugging information and extra validations.
811 config DEBUG_VM_PGFLAGS
812 bool "Debug page-flags operations"
815 Enables extra validation on page flags operations.
819 config DEBUG_VM_PGTABLE
820 bool "Debug arch page table for semantics compliance"
822 depends on ARCH_HAS_DEBUG_VM_PGTABLE
823 default y if DEBUG_VM
825 This option provides a debug method which can be used to test
826 architecture page table helper functions on various platforms in
827 verifying if they comply with expected generic MM semantics. This
828 will help architecture code in making sure that any changes or
829 new additions of these helpers still conform to expected
830 semantics of the generic MM. Platforms will have to opt in for
831 this through ARCH_HAS_DEBUG_VM_PGTABLE.
835 config ARCH_HAS_DEBUG_VIRTUAL
839 bool "Debug VM translations"
840 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
842 Enable some costly sanity checks in virtual to page code. This can
843 catch mistakes with virt_to_page() and friends.
847 config DEBUG_NOMMU_REGIONS
848 bool "Debug the global anon/private NOMMU mapping region tree"
849 depends on DEBUG_KERNEL && !MMU
851 This option causes the global tree of anonymous and private mapping
852 regions to be regularly checked for invalid topology.
854 config DEBUG_MEMORY_INIT
855 bool "Debug memory initialisation" if EXPERT
858 Enable this for additional checks during memory initialisation.
859 The sanity checks verify aspects of the VM such as the memory model
860 and other information provided by the architecture. Verbose
861 information will be printed at KERN_DEBUG loglevel depending
862 on the mminit_loglevel= command-line option.
866 config MEMORY_NOTIFIER_ERROR_INJECT
867 tristate "Memory hotplug notifier error injection module"
868 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
870 This option provides the ability to inject artificial errors to
871 memory hotplug notifier chain callbacks. It is controlled through
872 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
874 If the notifier call chain should be failed with some events
875 notified, write the error code to "actions/<notifier event>/error".
877 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
879 # cd /sys/kernel/debug/notifier-error-inject/memory
880 # echo -12 > actions/MEM_GOING_OFFLINE/error
881 # echo offline > /sys/devices/system/memory/memoryXXX/state
882 bash: echo: write error: Cannot allocate memory
884 To compile this code as a module, choose M here: the module will
885 be called memory-notifier-error-inject.
889 config DEBUG_PER_CPU_MAPS
890 bool "Debug access to per_cpu maps"
891 depends on DEBUG_KERNEL
894 Say Y to verify that the per_cpu map being accessed has
895 been set up. This adds a fair amount of code to kernel memory
896 and decreases performance.
900 config DEBUG_KMAP_LOCAL
901 bool "Debug kmap_local temporary mappings"
902 depends on DEBUG_KERNEL && KMAP_LOCAL
904 This option enables additional error checking for the kmap_local
905 infrastructure. Disable for production use.
907 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
910 config DEBUG_KMAP_LOCAL_FORCE_MAP
911 bool "Enforce kmap_local temporary mappings"
912 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
914 select DEBUG_KMAP_LOCAL
916 This option enforces temporary mappings through the kmap_local
917 mechanism for non-highmem pages and on non-highmem systems.
918 Disable this for production systems!
921 bool "Highmem debugging"
922 depends on DEBUG_KERNEL && HIGHMEM
923 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
924 select DEBUG_KMAP_LOCAL
926 This option enables additional error checking for high memory
927 systems. Disable for production systems.
929 config HAVE_DEBUG_STACKOVERFLOW
932 config DEBUG_STACKOVERFLOW
933 bool "Check for stack overflows"
934 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
936 Say Y here if you want to check for overflows of kernel, IRQ
937 and exception stacks (if your architecture uses them). This
938 option will show detailed messages if free stack space drops
939 below a certain limit.
941 These kinds of bugs usually occur when call-chains in the
942 kernel get too deep, especially when interrupts are
945 Use this in cases where you see apparently random memory
946 corruption, especially if it appears in 'struct thread_info'
948 If in doubt, say "N".
950 source "lib/Kconfig.kasan"
951 source "lib/Kconfig.kfence"
952 source "lib/Kconfig.kmsan"
954 endmenu # "Memory Debugging"
957 bool "Debug shared IRQ handlers"
958 depends on DEBUG_KERNEL
960 Enable this to generate a spurious interrupt just before a shared
961 interrupt handler is deregistered (generating one when registering
962 is currently disabled). Drivers need to handle this correctly. Some
963 don't and need to be caught.
965 menu "Debug Oops, Lockups and Hangs"
970 Say Y here to enable the kernel to panic when it oopses. This
971 has the same effect as setting oops=panic on the kernel command
974 This feature is useful to ensure that the kernel does not do
975 anything erroneous after an oops which could result in data
976 corruption or other issues.
980 config PANIC_ON_OOPS_VALUE
983 default 0 if !PANIC_ON_OOPS
984 default 1 if PANIC_ON_OOPS
990 Set the timeout value (in seconds) until a reboot occurs when
991 the kernel panics. If n = 0, then we wait forever. A timeout
992 value n > 0 will wait n seconds before rebooting, while a timeout
993 value n < 0 will reboot immediately.
995 config LOCKUP_DETECTOR
998 config SOFTLOCKUP_DETECTOR
999 bool "Detect Soft Lockups"
1000 depends on DEBUG_KERNEL && !S390
1001 select LOCKUP_DETECTOR
1003 Say Y here to enable the kernel to act as a watchdog to detect
1006 Softlockups are bugs that cause the kernel to loop in kernel
1007 mode for more than 20 seconds, without giving other tasks a
1008 chance to run. The current stack trace is displayed upon
1009 detection and the system will stay locked up.
1011 config BOOTPARAM_SOFTLOCKUP_PANIC
1012 bool "Panic (Reboot) On Soft Lockups"
1013 depends on SOFTLOCKUP_DETECTOR
1015 Say Y here to enable the kernel to panic on "soft lockups",
1016 which are bugs that cause the kernel to loop in kernel
1017 mode for more than 20 seconds (configurable using the watchdog_thresh
1018 sysctl), without giving other tasks a chance to run.
1020 The panic can be used in combination with panic_timeout,
1021 to cause the system to reboot automatically after a
1022 lockup has been detected. This feature is useful for
1023 high-availability systems that have uptime guarantees and
1024 where a lockup must be resolved ASAP.
1028 config HARDLOCKUP_DETECTOR_PERF
1030 select SOFTLOCKUP_DETECTOR
1033 # Enables a timestamp based low pass filter to compensate for perf based
1034 # hard lockup detection which runs too fast due to turbo modes.
1036 config HARDLOCKUP_CHECK_TIMESTAMP
1040 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1041 # lockup detector rather than the perf based detector.
1043 config HARDLOCKUP_DETECTOR
1044 bool "Detect Hard Lockups"
1045 depends on DEBUG_KERNEL && !S390
1046 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1047 select LOCKUP_DETECTOR
1048 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1050 Say Y here to enable the kernel to act as a watchdog to detect
1053 Hardlockups are bugs that cause the CPU to loop in kernel mode
1054 for more than 10 seconds, without letting other interrupts have a
1055 chance to run. The current stack trace is displayed upon detection
1056 and the system will stay locked up.
1058 config BOOTPARAM_HARDLOCKUP_PANIC
1059 bool "Panic (Reboot) On Hard Lockups"
1060 depends on HARDLOCKUP_DETECTOR
1062 Say Y here to enable the kernel to panic on "hard lockups",
1063 which are bugs that cause the kernel to loop in kernel
1064 mode with interrupts disabled for more than 10 seconds (configurable
1065 using the watchdog_thresh sysctl).
1069 config DETECT_HUNG_TASK
1070 bool "Detect Hung Tasks"
1071 depends on DEBUG_KERNEL
1072 default SOFTLOCKUP_DETECTOR
1074 Say Y here to enable the kernel to detect "hung tasks",
1075 which are bugs that cause the task to be stuck in
1076 uninterruptible "D" state indefinitely.
1078 When a hung task is detected, the kernel will print the
1079 current stack trace (which you should report), but the
1080 task will stay in uninterruptible state. If lockdep is
1081 enabled then all held locks will also be reported. This
1082 feature has negligible overhead.
1084 config DEFAULT_HUNG_TASK_TIMEOUT
1085 int "Default timeout for hung task detection (in seconds)"
1086 depends on DETECT_HUNG_TASK
1089 This option controls the default timeout (in seconds) used
1090 to determine when a task has become non-responsive and should
1093 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1094 sysctl or by writing a value to
1095 /proc/sys/kernel/hung_task_timeout_secs.
1097 A timeout of 0 disables the check. The default is two minutes.
1098 Keeping the default should be fine in most cases.
1100 config BOOTPARAM_HUNG_TASK_PANIC
1101 bool "Panic (Reboot) On Hung Tasks"
1102 depends on DETECT_HUNG_TASK
1104 Say Y here to enable the kernel to panic on "hung tasks",
1105 which are bugs that cause the kernel to leave a task stuck
1106 in uninterruptible "D" state.
1108 The panic can be used in combination with panic_timeout,
1109 to cause the system to reboot automatically after a
1110 hung task has been detected. This feature is useful for
1111 high-availability systems that have uptime guarantees and
1112 where a hung tasks must be resolved ASAP.
1117 bool "Detect Workqueue Stalls"
1118 depends on DEBUG_KERNEL
1120 Say Y here to enable stall detection on workqueues. If a
1121 worker pool doesn't make forward progress on a pending work
1122 item for over a given amount of time, 30s by default, a
1123 warning message is printed along with dump of workqueue
1124 state. This can be configured through kernel parameter
1125 "workqueue.watchdog_thresh" and its sysfs counterpart.
1128 tristate "Test module to generate lockups"
1131 This builds the "test_lockup" module that helps to make sure
1132 that watchdogs and lockup detectors are working properly.
1134 Depending on module parameters it could emulate soft or hard
1135 lockup, "hung task", or locking arbitrary lock for a long time.
1136 Also it could generate series of lockups with cooling-down periods.
1140 endmenu # "Debug lockups and hangs"
1142 menu "Scheduler Debugging"
1145 bool "Collect scheduler debugging info"
1146 depends on DEBUG_KERNEL && DEBUG_FS
1149 If you say Y here, the /sys/kernel/debug/sched file will be provided
1150 that can help debug the scheduler. The runtime overhead of this
1158 bool "Collect scheduler statistics"
1159 depends on DEBUG_KERNEL && PROC_FS
1162 If you say Y here, additional code will be inserted into the
1163 scheduler and related routines to collect statistics about
1164 scheduler behavior and provide them in /proc/schedstat. These
1165 stats may be useful for both tuning and debugging the scheduler
1166 If you aren't debugging the scheduler or trying to tune a specific
1167 application, you can say N to avoid the very slight overhead
1172 config DEBUG_TIMEKEEPING
1173 bool "Enable extra timekeeping sanity checking"
1175 This option will enable additional timekeeping sanity checks
1176 which may be helpful when diagnosing issues where timekeeping
1177 problems are suspected.
1179 This may include checks in the timekeeping hotpaths, so this
1180 option may have a (very small) performance impact to some
1185 config DEBUG_PREEMPT
1186 bool "Debug preemptible kernel"
1187 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1189 If you say Y here then the kernel will use a debug variant of the
1190 commonly used smp_processor_id() function and will print warnings
1191 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1192 will detect preemption count underflows.
1194 This option has potential to introduce high runtime overhead,
1195 depending on workload as it triggers debugging routines for each
1196 this_cpu operation. It should only be used for debugging purposes.
1198 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1200 config LOCK_DEBUGGING_SUPPORT
1202 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1205 config PROVE_LOCKING
1206 bool "Lock debugging: prove locking correctness"
1207 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1209 select DEBUG_SPINLOCK
1210 select DEBUG_MUTEXES if !PREEMPT_RT
1211 select DEBUG_RT_MUTEXES if RT_MUTEXES
1213 select DEBUG_WW_MUTEX_SLOWPATH
1214 select DEBUG_LOCK_ALLOC
1215 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1216 select TRACE_IRQFLAGS
1219 This feature enables the kernel to prove that all locking
1220 that occurs in the kernel runtime is mathematically
1221 correct: that under no circumstance could an arbitrary (and
1222 not yet triggered) combination of observed locking
1223 sequences (on an arbitrary number of CPUs, running an
1224 arbitrary number of tasks and interrupt contexts) cause a
1227 In short, this feature enables the kernel to report locking
1228 related deadlocks before they actually occur.
1230 The proof does not depend on how hard and complex a
1231 deadlock scenario would be to trigger: how many
1232 participant CPUs, tasks and irq-contexts would be needed
1233 for it to trigger. The proof also does not depend on
1234 timing: if a race and a resulting deadlock is possible
1235 theoretically (no matter how unlikely the race scenario
1236 is), it will be proven so and will immediately be
1237 reported by the kernel (once the event is observed that
1238 makes the deadlock theoretically possible).
1240 If a deadlock is impossible (i.e. the locking rules, as
1241 observed by the kernel, are mathematically correct), the
1242 kernel reports nothing.
1244 NOTE: this feature can also be enabled for rwlocks, mutexes
1245 and rwsems - in which case all dependencies between these
1246 different locking variants are observed and mapped too, and
1247 the proof of observed correctness is also maintained for an
1248 arbitrary combination of these separate locking variants.
1250 For more details, see Documentation/locking/lockdep-design.rst.
1252 config PROVE_RAW_LOCK_NESTING
1253 bool "Enable raw_spinlock - spinlock nesting checks"
1254 depends on PROVE_LOCKING
1257 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1258 that the lock nesting rules for PREEMPT_RT enabled kernels are
1261 NOTE: There are known nesting problems. So if you enable this
1262 option expect lockdep splats until these problems have been fully
1263 addressed which is work in progress. This config switch allows to
1264 identify and analyze these problems. It will be removed and the
1265 check permanently enabled once the main issues have been fixed.
1267 If unsure, select N.
1270 bool "Lock usage statistics"
1271 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1273 select DEBUG_SPINLOCK
1274 select DEBUG_MUTEXES if !PREEMPT_RT
1275 select DEBUG_RT_MUTEXES if RT_MUTEXES
1276 select DEBUG_LOCK_ALLOC
1279 This feature enables tracking lock contention points
1281 For more details, see Documentation/locking/lockstat.rst
1283 This also enables lock events required by "perf lock",
1285 If you want to use "perf lock", you also need to turn on
1286 CONFIG_EVENT_TRACING.
1288 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1289 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1291 config DEBUG_RT_MUTEXES
1292 bool "RT Mutex debugging, deadlock detection"
1293 depends on DEBUG_KERNEL && RT_MUTEXES
1295 This allows rt mutex semantics violations and rt mutex related
1296 deadlocks (lockups) to be detected and reported automatically.
1298 config DEBUG_SPINLOCK
1299 bool "Spinlock and rw-lock debugging: basic checks"
1300 depends on DEBUG_KERNEL
1301 select UNINLINE_SPIN_UNLOCK
1303 Say Y here and build SMP to catch missing spinlock initialization
1304 and certain other kinds of spinlock errors commonly made. This is
1305 best used in conjunction with the NMI watchdog so that spinlock
1306 deadlocks are also debuggable.
1308 config DEBUG_MUTEXES
1309 bool "Mutex debugging: basic checks"
1310 depends on DEBUG_KERNEL && !PREEMPT_RT
1312 This feature allows mutex semantics violations to be detected and
1315 config DEBUG_WW_MUTEX_SLOWPATH
1316 bool "Wait/wound mutex debugging: Slowpath testing"
1317 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1318 select DEBUG_LOCK_ALLOC
1319 select DEBUG_SPINLOCK
1320 select DEBUG_MUTEXES if !PREEMPT_RT
1321 select DEBUG_RT_MUTEXES if PREEMPT_RT
1323 This feature enables slowpath testing for w/w mutex users by
1324 injecting additional -EDEADLK wound/backoff cases. Together with
1325 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1326 will test all possible w/w mutex interface abuse with the
1327 exception of simply not acquiring all the required locks.
1328 Note that this feature can introduce significant overhead, so
1329 it really should not be enabled in a production or distro kernel,
1330 even a debug kernel. If you are a driver writer, enable it. If
1331 you are a distro, do not.
1334 bool "RW Semaphore debugging: basic checks"
1335 depends on DEBUG_KERNEL
1337 This debugging feature allows mismatched rw semaphore locks
1338 and unlocks to be detected and reported.
1340 config DEBUG_LOCK_ALLOC
1341 bool "Lock debugging: detect incorrect freeing of live locks"
1342 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1343 select DEBUG_SPINLOCK
1344 select DEBUG_MUTEXES if !PREEMPT_RT
1345 select DEBUG_RT_MUTEXES if RT_MUTEXES
1348 This feature will check whether any held lock (spinlock, rwlock,
1349 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1350 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1351 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1352 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1353 held during task exit.
1357 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1362 config LOCKDEP_SMALL
1366 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1367 depends on LOCKDEP && !LOCKDEP_SMALL
1371 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1373 config LOCKDEP_CHAINS_BITS
1374 int "Bitsize for MAX_LOCKDEP_CHAINS"
1375 depends on LOCKDEP && !LOCKDEP_SMALL
1379 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1381 config LOCKDEP_STACK_TRACE_BITS
1382 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1383 depends on LOCKDEP && !LOCKDEP_SMALL
1387 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1389 config LOCKDEP_STACK_TRACE_HASH_BITS
1390 int "Bitsize for STACK_TRACE_HASH_SIZE"
1391 depends on LOCKDEP && !LOCKDEP_SMALL
1395 Try increasing this value if you need large STACK_TRACE_HASH_SIZE.
1397 config LOCKDEP_CIRCULAR_QUEUE_BITS
1398 int "Bitsize for elements in circular_queue struct"
1403 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1405 config DEBUG_LOCKDEP
1406 bool "Lock dependency engine debugging"
1407 depends on DEBUG_KERNEL && LOCKDEP
1408 select DEBUG_IRQFLAGS
1410 If you say Y here, the lock dependency engine will do
1411 additional runtime checks to debug itself, at the price
1412 of more runtime overhead.
1414 config DEBUG_ATOMIC_SLEEP
1415 bool "Sleep inside atomic section checking"
1416 select PREEMPT_COUNT
1417 depends on DEBUG_KERNEL
1418 depends on !ARCH_NO_PREEMPT
1420 If you say Y here, various routines which may sleep will become very
1421 noisy if they are called inside atomic sections: when a spinlock is
1422 held, inside an rcu read side critical section, inside preempt disabled
1423 sections, inside an interrupt, etc...
1425 config DEBUG_LOCKING_API_SELFTESTS
1426 bool "Locking API boot-time self-tests"
1427 depends on DEBUG_KERNEL
1429 Say Y here if you want the kernel to run a short self-test during
1430 bootup. The self-test checks whether common types of locking bugs
1431 are detected by debugging mechanisms or not. (if you disable
1432 lock debugging then those bugs won't be detected of course.)
1433 The following locking APIs are covered: spinlocks, rwlocks,
1436 config LOCK_TORTURE_TEST
1437 tristate "torture tests for locking"
1438 depends on DEBUG_KERNEL
1441 This option provides a kernel module that runs torture tests
1442 on kernel locking primitives. The kernel module may be built
1443 after the fact on the running kernel to be tested, if desired.
1445 Say Y here if you want kernel locking-primitive torture tests
1446 to be built into the kernel.
1447 Say M if you want these torture tests to build as a module.
1448 Say N if you are unsure.
1450 config WW_MUTEX_SELFTEST
1451 tristate "Wait/wound mutex selftests"
1453 This option provides a kernel module that runs tests on the
1454 on the struct ww_mutex locking API.
1456 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1457 with this test harness.
1459 Say M if you want these self tests to build as a module.
1460 Say N if you are unsure.
1462 config SCF_TORTURE_TEST
1463 tristate "torture tests for smp_call_function*()"
1464 depends on DEBUG_KERNEL
1467 This option provides a kernel module that runs torture tests
1468 on the smp_call_function() family of primitives. The kernel
1469 module may be built after the fact on the running kernel to
1470 be tested, if desired.
1472 config CSD_LOCK_WAIT_DEBUG
1473 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1474 depends on DEBUG_KERNEL
1478 This option enables debug prints when CPUs are slow to respond
1479 to the smp_call_function*() IPI wrappers. These debug prints
1480 include the IPI handler function currently executing (if any)
1481 and relevant stack traces.
1483 endmenu # lock debugging
1485 config TRACE_IRQFLAGS
1486 depends on TRACE_IRQFLAGS_SUPPORT
1489 Enables hooks to interrupt enabling and disabling for
1490 either tracing or lock debugging.
1492 config TRACE_IRQFLAGS_NMI
1494 depends on TRACE_IRQFLAGS
1495 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1497 config NMI_CHECK_CPU
1498 bool "Debugging for CPUs failing to respond to backtrace requests"
1499 depends on DEBUG_KERNEL
1503 Enables debug prints when a CPU fails to respond to a given
1504 backtrace NMI. These prints provide some reasons why a CPU
1505 might legitimately be failing to respond, for example, if it
1506 is offline of if ignore_nmis is set.
1508 config DEBUG_IRQFLAGS
1509 bool "Debug IRQ flag manipulation"
1511 Enables checks for potentially unsafe enabling or disabling of
1512 interrupts, such as calling raw_local_irq_restore() when interrupts
1516 bool "Stack backtrace support"
1517 depends on STACKTRACE_SUPPORT
1519 This option causes the kernel to create a /proc/pid/stack for
1520 every process, showing its current stack trace.
1521 It is also used by various kernel debugging features that require
1522 stack trace generation.
1524 config WARN_ALL_UNSEEDED_RANDOM
1525 bool "Warn for all uses of unseeded randomness"
1528 Some parts of the kernel contain bugs relating to their use of
1529 cryptographically secure random numbers before it's actually possible
1530 to generate those numbers securely. This setting ensures that these
1531 flaws don't go unnoticed, by enabling a message, should this ever
1532 occur. This will allow people with obscure setups to know when things
1533 are going wrong, so that they might contact developers about fixing
1536 Unfortunately, on some models of some architectures getting
1537 a fully seeded CRNG is extremely difficult, and so this can
1538 result in dmesg getting spammed for a surprisingly long
1539 time. This is really bad from a security perspective, and
1540 so architecture maintainers really need to do what they can
1541 to get the CRNG seeded sooner after the system is booted.
1542 However, since users cannot do anything actionable to
1543 address this, by default this option is disabled.
1545 Say Y here if you want to receive warnings for all uses of
1546 unseeded randomness. This will be of use primarily for
1547 those developers interested in improving the security of
1548 Linux kernels running on their architecture (or
1551 config DEBUG_KOBJECT
1552 bool "kobject debugging"
1553 depends on DEBUG_KERNEL
1555 If you say Y here, some extra kobject debugging messages will be sent
1558 config DEBUG_KOBJECT_RELEASE
1559 bool "kobject release debugging"
1560 depends on DEBUG_OBJECTS_TIMERS
1562 kobjects are reference counted objects. This means that their
1563 last reference count put is not predictable, and the kobject can
1564 live on past the point at which a driver decides to drop its
1565 initial reference to the kobject gained on allocation. An
1566 example of this would be a struct device which has just been
1569 However, some buggy drivers assume that after such an operation,
1570 the memory backing the kobject can be immediately freed. This
1571 goes completely against the principles of a refcounted object.
1573 If you say Y here, the kernel will delay the release of kobjects
1574 on the last reference count to improve the visibility of this
1575 kind of kobject release bug.
1577 config HAVE_DEBUG_BUGVERBOSE
1580 menu "Debug kernel data structures"
1583 bool "Debug linked list manipulation"
1584 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1586 Enable this to turn on extended checks in the linked-list
1592 bool "Debug priority linked list manipulation"
1593 depends on DEBUG_KERNEL
1595 Enable this to turn on extended checks in the priority-ordered
1596 linked-list (plist) walking routines. This checks the entire
1597 list multiple times during each manipulation.
1602 bool "Debug SG table operations"
1603 depends on DEBUG_KERNEL
1605 Enable this to turn on checks on scatter-gather tables. This can
1606 help find problems with drivers that do not properly initialize
1611 config DEBUG_NOTIFIERS
1612 bool "Debug notifier call chains"
1613 depends on DEBUG_KERNEL
1615 Enable this to turn on sanity checking for notifier call chains.
1616 This is most useful for kernel developers to make sure that
1617 modules properly unregister themselves from notifier chains.
1618 This is a relatively cheap check but if you care about maximum
1621 config BUG_ON_DATA_CORRUPTION
1622 bool "Trigger a BUG when data corruption is detected"
1625 Select this option if the kernel should BUG when it encounters
1626 data corruption in kernel memory structures when they get checked
1631 config DEBUG_MAPLE_TREE
1632 bool "Debug maple trees"
1633 depends on DEBUG_KERNEL
1635 Enable maple tree debugging information and extra validations.
1641 config DEBUG_CREDENTIALS
1642 bool "Debug credential management"
1643 depends on DEBUG_KERNEL
1645 Enable this to turn on some debug checking for credential
1646 management. The additional code keeps track of the number of
1647 pointers from task_structs to any given cred struct, and checks to
1648 see that this number never exceeds the usage count of the cred
1651 Furthermore, if SELinux is enabled, this also checks that the
1652 security pointer in the cred struct is never seen to be invalid.
1656 source "kernel/rcu/Kconfig.debug"
1658 config DEBUG_WQ_FORCE_RR_CPU
1659 bool "Force round-robin CPU selection for unbound work items"
1660 depends on DEBUG_KERNEL
1663 Workqueue used to implicitly guarantee that work items queued
1664 without explicit CPU specified are put on the local CPU. This
1665 guarantee is no longer true and while local CPU is still
1666 preferred work items may be put on foreign CPUs. Kernel
1667 parameter "workqueue.debug_force_rr_cpu" is added to force
1668 round-robin CPU selection to flush out usages which depend on the
1669 now broken guarantee. This config option enables the debug
1670 feature by default. When enabled, memory and cache locality will
1673 config CPU_HOTPLUG_STATE_CONTROL
1674 bool "Enable CPU hotplug state control"
1675 depends on DEBUG_KERNEL
1676 depends on HOTPLUG_CPU
1679 Allows to write steps between "offline" and "online" to the CPUs
1680 sysfs target file so states can be stepped granular. This is a debug
1681 option for now as the hotplug machinery cannot be stopped and
1682 restarted at arbitrary points yet.
1684 Say N if your are unsure.
1687 bool "Latency measuring infrastructure"
1688 depends on DEBUG_KERNEL
1689 depends on STACKTRACE_SUPPORT
1691 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1697 Enable this option if you want to use the LatencyTOP tool
1698 to find out which userspace is blocking on what kernel operations.
1700 config DEBUG_CGROUP_REF
1701 bool "Disable inlining of cgroup css reference count functions"
1702 depends on DEBUG_KERNEL
1707 Force cgroup css reference count functions to not be inlined so
1708 that they can be kprobed for debugging.
1710 source "kernel/trace/Kconfig"
1712 config PROVIDE_OHCI1394_DMA_INIT
1713 bool "Remote debugging over FireWire early on boot"
1714 depends on PCI && X86
1716 If you want to debug problems which hang or crash the kernel early
1717 on boot and the crashing machine has a FireWire port, you can use
1718 this feature to remotely access the memory of the crashed machine
1719 over FireWire. This employs remote DMA as part of the OHCI1394
1720 specification which is now the standard for FireWire controllers.
1722 With remote DMA, you can monitor the printk buffer remotely using
1723 firescope and access all memory below 4GB using fireproxy from gdb.
1724 Even controlling a kernel debugger is possible using remote DMA.
1728 If ohci1394_dma=early is used as boot parameter, it will initialize
1729 all OHCI1394 controllers which are found in the PCI config space.
1731 As all changes to the FireWire bus such as enabling and disabling
1732 devices cause a bus reset and thereby disable remote DMA for all
1733 devices, be sure to have the cable plugged and FireWire enabled on
1734 the debugging host before booting the debug target for debugging.
1736 This code (~1k) is freed after boot. By then, the firewire stack
1737 in charge of the OHCI-1394 controllers should be used instead.
1739 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1741 source "samples/Kconfig"
1743 config ARCH_HAS_DEVMEM_IS_ALLOWED
1746 config STRICT_DEVMEM
1747 bool "Filter access to /dev/mem"
1748 depends on MMU && DEVMEM
1749 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1750 default y if PPC || X86 || ARM64
1752 If this option is disabled, you allow userspace (root) access to all
1753 of memory, including kernel and userspace memory. Accidental
1754 access to this is obviously disastrous, but specific access can
1755 be used by people debugging the kernel. Note that with PAT support
1756 enabled, even in this case there are restrictions on /dev/mem
1757 use due to the cache aliasing requirements.
1759 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1760 file only allows userspace access to PCI space and the BIOS code and
1761 data regions. This is sufficient for dosemu and X and all common
1766 config IO_STRICT_DEVMEM
1767 bool "Filter I/O access to /dev/mem"
1768 depends on STRICT_DEVMEM
1770 If this option is disabled, you allow userspace (root) access to all
1771 io-memory regardless of whether a driver is actively using that
1772 range. Accidental access to this is obviously disastrous, but
1773 specific access can be used by people debugging kernel drivers.
1775 If this option is switched on, the /dev/mem file only allows
1776 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1777 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1778 if the driver using a given range cannot be disabled.
1782 menu "$(SRCARCH) Debugging"
1784 source "arch/$(SRCARCH)/Kconfig.debug"
1788 menu "Kernel Testing and Coverage"
1790 source "lib/kunit/Kconfig"
1792 config NOTIFIER_ERROR_INJECTION
1793 tristate "Notifier error injection"
1794 depends on DEBUG_KERNEL
1797 This option provides the ability to inject artificial errors to
1798 specified notifier chain callbacks. It is useful to test the error
1799 handling of notifier call chain failures.
1803 config PM_NOTIFIER_ERROR_INJECT
1804 tristate "PM notifier error injection module"
1805 depends on PM && NOTIFIER_ERROR_INJECTION
1806 default m if PM_DEBUG
1808 This option provides the ability to inject artificial errors to
1809 PM notifier chain callbacks. It is controlled through debugfs
1810 interface /sys/kernel/debug/notifier-error-inject/pm
1812 If the notifier call chain should be failed with some events
1813 notified, write the error code to "actions/<notifier event>/error".
1815 Example: Inject PM suspend error (-12 = -ENOMEM)
1817 # cd /sys/kernel/debug/notifier-error-inject/pm/
1818 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1819 # echo mem > /sys/power/state
1820 bash: echo: write error: Cannot allocate memory
1822 To compile this code as a module, choose M here: the module will
1823 be called pm-notifier-error-inject.
1827 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1828 tristate "OF reconfig notifier error injection module"
1829 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1831 This option provides the ability to inject artificial errors to
1832 OF reconfig notifier chain callbacks. It is controlled
1833 through debugfs interface under
1834 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1836 If the notifier call chain should be failed with some events
1837 notified, write the error code to "actions/<notifier event>/error".
1839 To compile this code as a module, choose M here: the module will
1840 be called of-reconfig-notifier-error-inject.
1844 config NETDEV_NOTIFIER_ERROR_INJECT
1845 tristate "Netdev notifier error injection module"
1846 depends on NET && NOTIFIER_ERROR_INJECTION
1848 This option provides the ability to inject artificial errors to
1849 netdevice notifier chain callbacks. It is controlled through debugfs
1850 interface /sys/kernel/debug/notifier-error-inject/netdev
1852 If the notifier call chain should be failed with some events
1853 notified, write the error code to "actions/<notifier event>/error".
1855 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1857 # cd /sys/kernel/debug/notifier-error-inject/netdev
1858 # echo -22 > actions/NETDEV_CHANGEMTU/error
1859 # ip link set eth0 mtu 1024
1860 RTNETLINK answers: Invalid argument
1862 To compile this code as a module, choose M here: the module will
1863 be called netdev-notifier-error-inject.
1867 config FUNCTION_ERROR_INJECTION
1868 bool "Fault-injections of functions"
1869 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1871 Add fault injections into various functions that are annotated with
1872 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
1873 value of these functions. This is useful to test error paths of code.
1877 config FAULT_INJECTION
1878 bool "Fault-injection framework"
1879 depends on DEBUG_KERNEL
1881 Provide fault-injection framework.
1882 For more details, see Documentation/fault-injection/.
1885 bool "Fault-injection capability for kmalloc"
1886 depends on FAULT_INJECTION
1887 depends on SLAB || SLUB
1889 Provide fault-injection capability for kmalloc.
1891 config FAIL_PAGE_ALLOC
1892 bool "Fault-injection capability for alloc_pages()"
1893 depends on FAULT_INJECTION
1895 Provide fault-injection capability for alloc_pages().
1897 config FAULT_INJECTION_USERCOPY
1898 bool "Fault injection capability for usercopy functions"
1899 depends on FAULT_INJECTION
1901 Provides fault-injection capability to inject failures
1902 in usercopy functions (copy_from_user(), get_user(), ...).
1904 config FAIL_MAKE_REQUEST
1905 bool "Fault-injection capability for disk IO"
1906 depends on FAULT_INJECTION && BLOCK
1908 Provide fault-injection capability for disk IO.
1910 config FAIL_IO_TIMEOUT
1911 bool "Fault-injection capability for faking disk interrupts"
1912 depends on FAULT_INJECTION && BLOCK
1914 Provide fault-injection capability on end IO handling. This
1915 will make the block layer "forget" an interrupt as configured,
1916 thus exercising the error handling.
1918 Only works with drivers that use the generic timeout handling,
1919 for others it won't do anything.
1922 bool "Fault-injection capability for futexes"
1924 depends on FAULT_INJECTION && FUTEX
1926 Provide fault-injection capability for futexes.
1928 config FAULT_INJECTION_DEBUG_FS
1929 bool "Debugfs entries for fault-injection capabilities"
1930 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1932 Enable configuration of fault-injection capabilities via debugfs.
1934 config FAIL_FUNCTION
1935 bool "Fault-injection capability for functions"
1936 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1938 Provide function-based fault-injection capability.
1939 This will allow you to override a specific function with a return
1940 with given return value. As a result, function caller will see
1941 an error value and have to handle it. This is useful to test the
1942 error handling in various subsystems.
1944 config FAIL_MMC_REQUEST
1945 bool "Fault-injection capability for MMC IO"
1946 depends on FAULT_INJECTION_DEBUG_FS && MMC
1948 Provide fault-injection capability for MMC IO.
1949 This will make the mmc core return data errors. This is
1950 useful to test the error handling in the mmc block device
1951 and to test how the mmc host driver handles retries from
1955 bool "Fault-injection capability for SunRPC"
1956 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1958 Provide fault-injection capability for SunRPC and
1961 config FAULT_INJECTION_STACKTRACE_FILTER
1962 bool "stacktrace filter for fault-injection capabilities"
1963 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1965 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1967 Provide stacktrace filter for fault-injection capabilities
1969 config ARCH_HAS_KCOV
1972 An architecture should select this when it can successfully
1973 build and run with CONFIG_KCOV. This typically requires
1974 disabling instrumentation for some early boot code.
1976 config CC_HAS_SANCOV_TRACE_PC
1977 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1981 bool "Code coverage for fuzzing"
1982 depends on ARCH_HAS_KCOV
1983 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1984 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
1985 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
1987 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1988 select OBJTOOL if HAVE_NOINSTR_HACK
1990 KCOV exposes kernel code coverage information in a form suitable
1991 for coverage-guided fuzzing (randomized testing).
1993 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1994 different machines and across reboots. If you need stable PC values,
1995 disable RANDOMIZE_BASE.
1997 For more details, see Documentation/dev-tools/kcov.rst.
1999 config KCOV_ENABLE_COMPARISONS
2000 bool "Enable comparison operands collection by KCOV"
2002 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2004 KCOV also exposes operands of every comparison in the instrumented
2005 code along with operand sizes and PCs of the comparison instructions.
2006 These operands can be used by fuzzing engines to improve the quality
2007 of fuzzing coverage.
2009 config KCOV_INSTRUMENT_ALL
2010 bool "Instrument all code by default"
2014 If you are doing generic system call fuzzing (like e.g. syzkaller),
2015 then you will want to instrument the whole kernel and you should
2016 say y here. If you are doing more targeted fuzzing (like e.g.
2017 filesystem fuzzing with AFL) then you will want to enable coverage
2018 for more specific subsets of files, and should say n here.
2020 config KCOV_IRQ_AREA_SIZE
2021 hex "Size of interrupt coverage collection area in words"
2025 KCOV uses preallocated per-cpu areas to collect coverage from
2026 soft interrupts. This specifies the size of those areas in the
2027 number of unsigned long words.
2029 menuconfig RUNTIME_TESTING_MENU
2030 bool "Runtime Testing"
2033 if RUNTIME_TESTING_MENU
2036 tristate "Dhrystone benchmark test"
2038 Enable this to include the Dhrystone 2.1 benchmark. This test
2039 calculates the number of Dhrystones per second, and the number of
2040 DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided
2041 by 1757 (the number of Dhrystones per second obtained on the VAX
2042 11/780, nominally a 1 MIPS machine).
2044 To run the benchmark, it needs to be enabled explicitly, either from
2045 the kernel command line (when built-in), or from userspace (when
2046 built-in or modular.
2048 Run once during kernel boot:
2052 Set number of iterations from kernel command line:
2054 test_dhry.iterations=<n>
2056 Set number of iterations from userspace:
2058 echo <n> > /sys/module/test_dhry/parameters/iterations
2060 Trigger manual run from userspace:
2062 echo y > /sys/module/test_dhry/parameters/run
2064 If the number of iterations is <= 0, the test will devise a suitable
2065 number of iterations (test runs for at least 2s) automatically.
2066 This process takes ca. 4s.
2071 tristate "Linux Kernel Dump Test Tool Module"
2074 This module enables testing of the different dumping mechanisms by
2075 inducing system failures at predefined crash points.
2076 If you don't need it: say N
2077 Choose M here to compile this code as a module. The module will be
2080 Documentation on how to use the module can be found in
2081 Documentation/fault-injection/provoke-crashes.rst
2083 config CPUMASK_KUNIT_TEST
2084 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2086 default KUNIT_ALL_TESTS
2088 Enable to turn on cpumask tests, running at boot or module load time.
2090 For more information on KUnit and unit tests in general, please refer
2091 to the KUnit documentation in Documentation/dev-tools/kunit/.
2095 config TEST_LIST_SORT
2096 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2098 default KUNIT_ALL_TESTS
2100 Enable this to turn on 'list_sort()' function test. This test is
2101 executed only once during system boot (so affects only boot time),
2102 or at module load time.
2106 config TEST_MIN_HEAP
2107 tristate "Min heap test"
2108 depends on DEBUG_KERNEL || m
2110 Enable this to turn on min heap function tests. This test is
2111 executed only once during system boot (so affects only boot time),
2112 or at module load time.
2117 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2119 default KUNIT_ALL_TESTS
2121 This option enables the self-test function of 'sort()' at boot,
2122 or at module load time.
2127 tristate "64bit/32bit division and modulo test"
2128 depends on DEBUG_KERNEL || m
2130 Enable this to turn on 'do_div()' function test. This test is
2131 executed only once during system boot (so affects only boot time),
2132 or at module load time.
2136 config KPROBES_SANITY_TEST
2137 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2138 depends on DEBUG_KERNEL
2141 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2142 default KUNIT_ALL_TESTS
2144 This option provides for testing basic kprobes functionality on
2145 boot. Samples of kprobe and kretprobe are inserted and
2146 verified for functionality.
2148 Say N if you are unsure.
2150 config FPROBE_SANITY_TEST
2151 bool "Self test for fprobe"
2152 depends on DEBUG_KERNEL
2156 This option will enable testing the fprobe when the system boot.
2157 A series of tests are made to verify that the fprobe is functioning
2160 Say N if you are unsure.
2162 config BACKTRACE_SELF_TEST
2163 tristate "Self test for the backtrace code"
2164 depends on DEBUG_KERNEL
2166 This option provides a kernel module that can be used to test
2167 the kernel stack backtrace code. This option is not useful
2168 for distributions or general kernels, but only for kernel
2169 developers working on architecture code.
2171 Note that if you want to also test saved backtraces, you will
2172 have to enable STACKTRACE as well.
2174 Say N if you are unsure.
2176 config TEST_REF_TRACKER
2177 tristate "Self test for reference tracker"
2178 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2181 This option provides a kernel module performing tests
2182 using reference tracker infrastructure.
2184 Say N if you are unsure.
2187 tristate "Red-Black tree test"
2188 depends on DEBUG_KERNEL
2190 A benchmark measuring the performance of the rbtree library.
2191 Also includes rbtree invariant checks.
2193 config REED_SOLOMON_TEST
2194 tristate "Reed-Solomon library test"
2195 depends on DEBUG_KERNEL || m
2197 select REED_SOLOMON_ENC16
2198 select REED_SOLOMON_DEC16
2200 This option enables the self-test function of rslib at boot,
2201 or at module load time.
2205 config INTERVAL_TREE_TEST
2206 tristate "Interval tree test"
2207 depends on DEBUG_KERNEL
2208 select INTERVAL_TREE
2210 A benchmark measuring the performance of the interval tree library
2213 tristate "Per cpu operations test"
2214 depends on m && DEBUG_KERNEL
2216 Enable this option to build test module which validates per-cpu
2221 config ATOMIC64_SELFTEST
2222 tristate "Perform an atomic64_t self-test"
2224 Enable this option to test the atomic64_t functions at boot or
2225 at module load time.
2229 config ASYNC_RAID6_TEST
2230 tristate "Self test for hardware accelerated raid6 recovery"
2231 depends on ASYNC_RAID6_RECOV
2234 This is a one-shot self test that permutes through the
2235 recovery of all the possible two disk failure scenarios for a
2236 N-disk array. Recovery is performed with the asynchronous
2237 raid6 recovery routines, and will optionally use an offload
2238 engine if one is available.
2243 tristate "Test functions located in the hexdump module at runtime"
2245 config STRING_SELFTEST
2246 tristate "Test string functions at runtime"
2248 config TEST_STRING_HELPERS
2249 tristate "Test functions located in the string_helpers module at runtime"
2252 tristate "Test kstrto*() family of functions at runtime"
2255 tristate "Test printf() family of functions at runtime"
2258 tristate "Test scanf() family of functions at runtime"
2261 tristate "Test bitmap_*() family of functions at runtime"
2263 Enable this option to test the bitmap functions at boot.
2268 tristate "Test functions located in the uuid module at runtime"
2271 tristate "Test the XArray code at runtime"
2273 config TEST_MAPLE_TREE
2274 depends on DEBUG_KERNEL
2275 select DEBUG_MAPLE_TREE
2276 tristate "Test the Maple Tree code at runtime"
2278 config TEST_RHASHTABLE
2279 tristate "Perform selftest on resizable hash table"
2281 Enable this option to test the rhashtable functions at boot.
2286 tristate "Perform selftest on IDA functions"
2289 tristate "Perform selftest on priority array manager"
2292 Enable this option to test priority array manager on boot
2297 config TEST_IRQ_TIMINGS
2298 bool "IRQ timings selftest"
2299 depends on IRQ_TIMINGS
2301 Enable this option to test the irq timings code on boot.
2306 tristate "Test module loading with 'hello world' module"
2309 This builds the "test_module" module that emits "Hello, world"
2310 on printk when loaded. It is designed to be used for basic
2311 evaluation of the module loading subsystem (for example when
2312 validating module verification). It lacks any extra dependencies,
2313 and will not normally be loaded by the system unless explicitly
2319 tristate "Test module for compilation of bitops operations"
2322 This builds the "test_bitops" module that is much like the
2323 TEST_LKM module except that it does a basic exercise of the
2324 set/clear_bit macros and get_count_order/long to make sure there are
2325 no compiler warnings from C=1 sparse checker or -Wextra
2326 compilations. It has no dependencies and doesn't run or load unless
2327 explicitly requested by name. for example: modprobe test_bitops.
2332 tristate "Test module for stress/performance analysis of vmalloc allocator"
2337 This builds the "test_vmalloc" module that should be used for
2338 stress and performance analysis. So, any new change for vmalloc
2339 subsystem can be evaluated from performance and stability point
2344 config TEST_USER_COPY
2345 tristate "Test user/kernel boundary protections"
2348 This builds the "test_user_copy" module that runs sanity checks
2349 on the copy_to/from_user infrastructure, making sure basic
2350 user/kernel boundary testing is working. If it fails to load,
2351 a regression has been detected in the user/kernel memory boundary
2357 tristate "Test BPF filter functionality"
2360 This builds the "test_bpf" module that runs various test vectors
2361 against the BPF interpreter or BPF JIT compiler depending on the
2362 current setting. This is in particular useful for BPF JIT compiler
2363 development, but also to run regression tests against changes in
2364 the interpreter code. It also enables test stubs for eBPF maps and
2365 verifier used by user space verifier testsuite.
2369 config TEST_BLACKHOLE_DEV
2370 tristate "Test blackhole netdev functionality"
2373 This builds the "test_blackhole_dev" module that validates the
2374 data path through this blackhole netdev.
2378 config FIND_BIT_BENCHMARK
2379 tristate "Test find_bit functions"
2381 This builds the "test_find_bit" module that measure find_*_bit()
2382 functions performance.
2386 config TEST_FIRMWARE
2387 tristate "Test firmware loading via userspace interface"
2388 depends on FW_LOADER
2390 This builds the "test_firmware" module that creates a userspace
2391 interface for testing firmware loading. This can be used to
2392 control the triggering of firmware loading without needing an
2393 actual firmware-using device. The contents can be rechecked by
2399 tristate "sysctl test driver"
2400 depends on PROC_SYSCTL
2402 This builds the "test_sysctl" module. This driver enables to test the
2403 proc sysctl interfaces available to drivers safely without affecting
2404 production knobs which might alter system functionality.
2408 config BITFIELD_KUNIT
2409 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2411 default KUNIT_ALL_TESTS
2413 Enable this option to test the bitfield functions at boot.
2415 KUnit tests run during boot and output the results to the debug log
2416 in TAP format (http://testanything.org/). Only useful for kernel devs
2417 running the KUnit test harness, and not intended for inclusion into a
2420 For more information on KUnit and unit tests in general please refer
2421 to the KUnit documentation in Documentation/dev-tools/kunit/.
2425 config HASH_KUNIT_TEST
2426 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2428 default KUNIT_ALL_TESTS
2430 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2431 integer (<linux/hash.h>) hash functions on boot.
2433 KUnit tests run during boot and output the results to the debug log
2434 in TAP format (https://testanything.org/). Only useful for kernel devs
2435 running the KUnit test harness, and not intended for inclusion into a
2438 For more information on KUnit and unit tests in general please refer
2439 to the KUnit documentation in Documentation/dev-tools/kunit/.
2441 This is intended to help people writing architecture-specific
2442 optimized versions. If unsure, say N.
2444 config RESOURCE_KUNIT_TEST
2445 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2447 default KUNIT_ALL_TESTS
2449 This builds the resource API unit test.
2450 Tests the logic of API provided by resource.c and ioport.h.
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 SYSCTL_KUNIT_TEST
2457 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2459 default KUNIT_ALL_TESTS
2461 This builds the proc sysctl unit test, which runs on boot.
2462 Tests the API contract and implementation correctness of sysctl.
2463 For more information on KUnit and unit tests in general please refer
2464 to the KUnit documentation in Documentation/dev-tools/kunit/.
2468 config LIST_KUNIT_TEST
2469 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2471 default KUNIT_ALL_TESTS
2473 This builds the linked list KUnit test suite.
2474 It tests that the API and basic functionality of the list_head type
2475 and associated macros.
2477 KUnit tests run during boot and output the results to the debug log
2478 in TAP format (https://testanything.org/). Only useful for kernel devs
2479 running the KUnit test harness, and not intended for inclusion into a
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 HASHTABLE_KUNIT_TEST
2488 tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS
2490 default KUNIT_ALL_TESTS
2492 This builds the hashtable KUnit test suite.
2493 It tests the basic functionality of the API defined in
2494 include/linux/hashtable.h. For more information on KUnit and
2495 unit tests in general please refer to the KUnit documentation
2496 in Documentation/dev-tools/kunit/.
2500 config LINEAR_RANGES_TEST
2501 tristate "KUnit test for linear_ranges"
2503 select LINEAR_RANGES
2505 This builds the linear_ranges unit test, which runs on boot.
2506 Tests the linear_ranges logic correctness.
2507 For more information on KUnit and unit tests in general please refer
2508 to the KUnit documentation in Documentation/dev-tools/kunit/.
2512 config CMDLINE_KUNIT_TEST
2513 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2515 default KUNIT_ALL_TESTS
2517 This builds the cmdline API unit test.
2518 Tests the logic of API provided by cmdline.c.
2519 For more information on KUnit and unit tests in general please refer
2520 to the KUnit documentation in Documentation/dev-tools/kunit/.
2525 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2527 default KUNIT_ALL_TESTS
2529 This builds the bits unit test.
2530 Tests the logic of macros defined in bits.h.
2531 For more information on KUnit and unit tests in general please refer
2532 to the KUnit documentation in Documentation/dev-tools/kunit/.
2536 config SLUB_KUNIT_TEST
2537 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2538 depends on SLUB_DEBUG && KUNIT
2539 default KUNIT_ALL_TESTS
2541 This builds SLUB allocator unit test.
2542 Tests SLUB cache debugging functionality.
2543 For more information on KUnit and unit tests in general please refer
2544 to the KUnit documentation in Documentation/dev-tools/kunit/.
2548 config RATIONAL_KUNIT_TEST
2549 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2550 depends on KUNIT && RATIONAL
2551 default KUNIT_ALL_TESTS
2553 This builds the rational math unit test.
2554 For more information on KUnit and unit tests in general please refer
2555 to the KUnit documentation in Documentation/dev-tools/kunit/.
2559 config MEMCPY_KUNIT_TEST
2560 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2562 default KUNIT_ALL_TESTS
2564 Builds unit tests for memcpy(), memmove(), and memset() functions.
2565 For more information on KUnit and unit tests in general please refer
2566 to the KUnit documentation in Documentation/dev-tools/kunit/.
2570 config MEMCPY_SLOW_KUNIT_TEST
2571 bool "Include exhaustive memcpy tests"
2572 depends on MEMCPY_KUNIT_TEST
2575 Some memcpy tests are quite exhaustive in checking for overlaps
2576 and bit ranges. These can be very slow, so they are split out
2577 as a separate config, in case they need to be disabled.
2579 config IS_SIGNED_TYPE_KUNIT_TEST
2580 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2582 default KUNIT_ALL_TESTS
2584 Builds unit tests for the is_signed_type() macro.
2586 For more information on KUnit and unit tests in general please refer
2587 to the KUnit documentation in Documentation/dev-tools/kunit/.
2591 config OVERFLOW_KUNIT_TEST
2592 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2594 default KUNIT_ALL_TESTS
2596 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2599 For more information on KUnit and unit tests in general please refer
2600 to the KUnit documentation in Documentation/dev-tools/kunit/.
2604 config STACKINIT_KUNIT_TEST
2605 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2607 default KUNIT_ALL_TESTS
2609 Test if the kernel is zero-initializing stack variables and
2610 padding. Coverage is controlled by compiler flags,
2611 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2612 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2613 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2615 config FORTIFY_KUNIT_TEST
2616 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2617 depends on KUNIT && FORTIFY_SOURCE
2618 default KUNIT_ALL_TESTS
2620 Builds unit tests for checking internals of FORTIFY_SOURCE as used
2621 by the str*() and mem*() family of functions. For testing runtime
2622 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2624 config HW_BREAKPOINT_KUNIT_TEST
2625 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2626 depends on HAVE_HW_BREAKPOINT
2628 default KUNIT_ALL_TESTS
2630 Tests for hw_breakpoint constraints accounting.
2634 config STRSCPY_KUNIT_TEST
2635 tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS
2637 default KUNIT_ALL_TESTS
2639 config SIPHASH_KUNIT_TEST
2640 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2642 default KUNIT_ALL_TESTS
2644 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2645 functions on boot (or module load).
2647 This is intended to help people writing architecture-specific
2648 optimized versions. If unsure, say N.
2651 tristate "udelay test driver"
2653 This builds the "udelay_test" module that helps to make sure
2654 that udelay() is working properly.
2658 config TEST_STATIC_KEYS
2659 tristate "Test static keys"
2662 Test the static key interfaces.
2666 config TEST_DYNAMIC_DEBUG
2667 tristate "Test DYNAMIC_DEBUG"
2668 depends on DYNAMIC_DEBUG
2670 This module registers a tracer callback to count enabled
2671 pr_debugs in a 'do_debugging' function, then alters their
2672 enablements, calls the function, and compares counts.
2677 tristate "kmod stress tester"
2679 depends on NETDEVICES && NET_CORE && INET # for TUN
2681 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2687 Test the kernel's module loading mechanism: kmod. kmod implements
2688 support to load modules using the Linux kernel's usermode helper.
2689 This test provides a series of tests against kmod.
2691 Although technically you can either build test_kmod as a module or
2692 into the kernel we disallow building it into the kernel since
2693 it stress tests request_module() and this will very likely cause
2694 some issues by taking over precious threads available from other
2695 module load requests, ultimately this could be fatal.
2699 tools/testing/selftests/kmod/kmod.sh --help
2703 config TEST_DEBUG_VIRTUAL
2704 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2705 depends on DEBUG_VIRTUAL
2707 Test the kernel's ability to detect incorrect calls to
2708 virt_to_phys() done against the non-linear part of the
2709 kernel's virtual address map.
2713 config TEST_MEMCAT_P
2714 tristate "Test memcat_p() helper function"
2716 Test the memcat_p() helper for correctly merging two
2717 pointer arrays together.
2721 config TEST_LIVEPATCH
2722 tristate "Test livepatching"
2724 depends on DYNAMIC_DEBUG
2725 depends on LIVEPATCH
2728 Test kernel livepatching features for correctness. The tests will
2729 load test modules that will be livepatched in various scenarios.
2731 To run all the livepatching tests:
2733 make -C tools/testing/selftests TARGETS=livepatch run_tests
2735 Alternatively, individual tests may be invoked:
2737 tools/testing/selftests/livepatch/test-callbacks.sh
2738 tools/testing/selftests/livepatch/test-livepatch.sh
2739 tools/testing/selftests/livepatch/test-shadow-vars.sh
2744 tristate "Perform selftest on object aggreration manager"
2748 Enable this option to test object aggregation manager on boot
2752 tristate "Test heap/page initialization"
2754 Test if the kernel is zero-initializing heap and page allocations.
2755 This can be useful to test init_on_alloc and init_on_free features.
2760 tristate "Test HMM (Heterogeneous Memory Management)"
2761 depends on TRANSPARENT_HUGEPAGE
2762 depends on DEVICE_PRIVATE
2766 This is a pseudo device driver solely for testing HMM.
2767 Say M here if you want to build the HMM test module.
2768 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2772 config TEST_FREE_PAGES
2773 tristate "Test freeing pages"
2775 Test that a memory leak does not occur due to a race between
2776 freeing a block of pages and a speculative page reference.
2777 Loading this module is safe if your kernel has the bug fixed.
2778 If the bug is not fixed, it will leak gigabytes of memory and
2779 probably OOM your system.
2782 tristate "Test floating point operations in kernel space"
2783 depends on X86 && !KCOV_INSTRUMENT_ALL
2785 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2786 which will trigger a sequence of floating point operations. This is used
2787 for self-testing floating point control register setting in
2792 config TEST_CLOCKSOURCE_WATCHDOG
2793 tristate "Test clocksource watchdog in kernel space"
2794 depends on CLOCKSOURCE_WATCHDOG
2796 Enable this option to create a kernel module that will trigger
2797 a test of the clocksource watchdog. This module may be loaded
2798 via modprobe or insmod in which case it will run upon being
2799 loaded, or it may be built in, in which case it will run
2804 endif # RUNTIME_TESTING_MENU
2806 config ARCH_USE_MEMTEST
2809 An architecture should select this when it uses early_memtest()
2810 during boot process.
2814 depends on ARCH_USE_MEMTEST
2816 This option adds a kernel parameter 'memtest', which allows memtest
2817 to be set and executed.
2818 memtest=0, mean disabled; -- default
2819 memtest=1, mean do 1 test pattern;
2821 memtest=17, mean do 17 test patterns.
2822 If you are unsure how to answer this question, answer N.
2826 config HYPERV_TESTING
2827 bool "Microsoft Hyper-V driver testing"
2829 depends on HYPERV && DEBUG_FS
2831 Select this option to enable Hyper-V vmbus testing.
2833 endmenu # "Kernel Testing and Coverage"
2837 config RUST_DEBUG_ASSERTIONS
2838 bool "Debug assertions"
2841 Enables rustc's `-Cdebug-assertions` codegen option.
2843 This flag lets you turn `cfg(debug_assertions)` conditional
2844 compilation on or off. This can be used to enable extra debugging
2845 code in development but not in production. For example, it controls
2846 the behavior of the standard library's `debug_assert!` macro.
2848 Note that this will apply to all Rust code, including `core`.
2852 config RUST_OVERFLOW_CHECKS
2853 bool "Overflow checks"
2857 Enables rustc's `-Coverflow-checks` codegen option.
2859 This flag allows you to control the behavior of runtime integer
2860 overflow. When overflow-checks are enabled, a Rust panic will occur
2863 Note that this will apply to all Rust code, including `core`.
2867 config RUST_BUILD_ASSERT_ALLOW
2868 bool "Allow unoptimized build-time assertions"
2871 Controls how are `build_error!` and `build_assert!` handled during build.
2873 If calls to them exist in the binary, it may indicate a violated invariant
2874 or that the optimizer failed to verify the invariant during compilation.
2876 This should not happen, thus by default the build is aborted. However,
2877 as an escape hatch, you can choose Y here to ignore them during build
2878 and let the check be carried at runtime (with `panic!` being called if
2885 endmenu # Kernel hacking
projects / linux-block.git / blob