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 HAVE_DEBUG_KMEMLEAK
758 config DEBUG_KMEMLEAK
759 bool "Kernel memory leak detector"
760 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
762 select STACKTRACE if STACKTRACE_SUPPORT
767 Say Y here if you want to enable the memory leak
768 detector. The memory allocation/freeing is traced in a way
769 similar to the Boehm's conservative garbage collector, the
770 difference being that the orphan objects are not freed but
771 only shown in /sys/kernel/debug/kmemleak. Enabling this
772 feature will introduce an overhead to memory
773 allocations. See Documentation/dev-tools/kmemleak.rst for more
776 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
777 of finding leaks due to the slab objects poisoning.
779 In order to access the kmemleak file, debugfs needs to be
780 mounted (usually at /sys/kernel/debug).
782 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
783 int "Kmemleak memory pool size"
784 depends on DEBUG_KMEMLEAK
788 Kmemleak must track all the memory allocations to avoid
789 reporting false positives. Since memory may be allocated or
790 freed before kmemleak is fully initialised, use a static pool
791 of metadata objects to track such callbacks. After kmemleak is
792 fully initialised, this memory pool acts as an emergency one
793 if slab allocations fail.
795 config DEBUG_KMEMLEAK_TEST
796 tristate "Simple test for the kernel memory leak detector"
797 depends on DEBUG_KMEMLEAK && m
799 This option enables a module that explicitly leaks memory.
803 config DEBUG_KMEMLEAK_DEFAULT_OFF
804 bool "Default kmemleak to off"
805 depends on DEBUG_KMEMLEAK
807 Say Y here to disable kmemleak by default. It can then be enabled
808 on the command line via kmemleak=on.
810 config DEBUG_KMEMLEAK_AUTO_SCAN
811 bool "Enable kmemleak auto scan thread on boot up"
813 depends on DEBUG_KMEMLEAK
815 Depending on the cpu, kmemleak scan may be cpu intensive and can
816 stall user tasks at times. This option enables/disables automatic
817 kmemleak scan at boot up.
819 Say N here to disable kmemleak auto scan thread to stop automatic
820 scanning. Disabling this option disables automatic reporting of
825 config DEBUG_STACK_USAGE
826 bool "Stack utilization instrumentation"
827 depends on DEBUG_KERNEL && !IA64
829 Enables the display of the minimum amount of free stack which each
830 task has ever had available in the sysrq-T and sysrq-P debug output.
832 This option will slow down process creation somewhat.
834 config SCHED_STACK_END_CHECK
835 bool "Detect stack corruption on calls to schedule()"
836 depends on DEBUG_KERNEL
839 This option checks for a stack overrun on calls to schedule().
840 If the stack end location is found to be over written always panic as
841 the content of the corrupted region can no longer be trusted.
842 This is to ensure no erroneous behaviour occurs which could result in
843 data corruption or a sporadic crash at a later stage once the region
844 is examined. The runtime overhead introduced is minimal.
846 config ARCH_HAS_DEBUG_VM_PGTABLE
849 An architecture should select this when it can successfully
850 build and run DEBUG_VM_PGTABLE.
852 config DEBUG_VM_IRQSOFF
853 def_bool DEBUG_VM && !PREEMPT_RT
857 depends on DEBUG_KERNEL
859 Enable this to turn on extended checks in the virtual-memory system
860 that may impact performance.
864 config DEBUG_VM_MAPLE_TREE
865 bool "Debug VM maple trees"
867 select DEBUG_MAPLE_TREE
869 Enable VM maple tree debugging information and extra validations.
874 bool "Debug VM red-black trees"
877 Enable VM red-black tree debugging information and extra validations.
881 config DEBUG_VM_PGFLAGS
882 bool "Debug page-flags operations"
885 Enables extra validation on page flags operations.
889 config DEBUG_VM_PGTABLE
890 bool "Debug arch page table for semantics compliance"
892 depends on ARCH_HAS_DEBUG_VM_PGTABLE
893 default y if DEBUG_VM
895 This option provides a debug method which can be used to test
896 architecture page table helper functions on various platforms in
897 verifying if they comply with expected generic MM semantics. This
898 will help architecture code in making sure that any changes or
899 new additions of these helpers still conform to expected
900 semantics of the generic MM. Platforms will have to opt in for
901 this through ARCH_HAS_DEBUG_VM_PGTABLE.
905 config ARCH_HAS_DEBUG_VIRTUAL
909 bool "Debug VM translations"
910 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
912 Enable some costly sanity checks in virtual to page code. This can
913 catch mistakes with virt_to_page() and friends.
917 config DEBUG_NOMMU_REGIONS
918 bool "Debug the global anon/private NOMMU mapping region tree"
919 depends on DEBUG_KERNEL && !MMU
921 This option causes the global tree of anonymous and private mapping
922 regions to be regularly checked for invalid topology.
924 config DEBUG_MEMORY_INIT
925 bool "Debug memory initialisation" if EXPERT
928 Enable this for additional checks during memory initialisation.
929 The sanity checks verify aspects of the VM such as the memory model
930 and other information provided by the architecture. Verbose
931 information will be printed at KERN_DEBUG loglevel depending
932 on the mminit_loglevel= command-line option.
936 config MEMORY_NOTIFIER_ERROR_INJECT
937 tristate "Memory hotplug notifier error injection module"
938 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
940 This option provides the ability to inject artificial errors to
941 memory hotplug notifier chain callbacks. It is controlled through
942 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
944 If the notifier call chain should be failed with some events
945 notified, write the error code to "actions/<notifier event>/error".
947 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
949 # cd /sys/kernel/debug/notifier-error-inject/memory
950 # echo -12 > actions/MEM_GOING_OFFLINE/error
951 # echo offline > /sys/devices/system/memory/memoryXXX/state
952 bash: echo: write error: Cannot allocate memory
954 To compile this code as a module, choose M here: the module will
955 be called memory-notifier-error-inject.
959 config DEBUG_PER_CPU_MAPS
960 bool "Debug access to per_cpu maps"
961 depends on DEBUG_KERNEL
964 Say Y to verify that the per_cpu map being accessed has
965 been set up. This adds a fair amount of code to kernel memory
966 and decreases performance.
970 config DEBUG_KMAP_LOCAL
971 bool "Debug kmap_local temporary mappings"
972 depends on DEBUG_KERNEL && KMAP_LOCAL
974 This option enables additional error checking for the kmap_local
975 infrastructure. Disable for production use.
977 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
980 config DEBUG_KMAP_LOCAL_FORCE_MAP
981 bool "Enforce kmap_local temporary mappings"
982 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
984 select DEBUG_KMAP_LOCAL
986 This option enforces temporary mappings through the kmap_local
987 mechanism for non-highmem pages and on non-highmem systems.
988 Disable this for production systems!
991 bool "Highmem debugging"
992 depends on DEBUG_KERNEL && HIGHMEM
993 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
994 select DEBUG_KMAP_LOCAL
996 This option enables additional error checking for high memory
997 systems. Disable for production systems.
999 config HAVE_DEBUG_STACKOVERFLOW
1002 config DEBUG_STACKOVERFLOW
1003 bool "Check for stack overflows"
1004 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
1006 Say Y here if you want to check for overflows of kernel, IRQ
1007 and exception stacks (if your architecture uses them). This
1008 option will show detailed messages if free stack space drops
1009 below a certain limit.
1011 These kinds of bugs usually occur when call-chains in the
1012 kernel get too deep, especially when interrupts are
1015 Use this in cases where you see apparently random memory
1016 corruption, especially if it appears in 'struct thread_info'
1018 If in doubt, say "N".
1020 source "lib/Kconfig.kasan"
1021 source "lib/Kconfig.kfence"
1022 source "lib/Kconfig.kmsan"
1024 endmenu # "Memory Debugging"
1027 bool "Debug shared IRQ handlers"
1028 depends on DEBUG_KERNEL
1030 Enable this to generate a spurious interrupt just before a shared
1031 interrupt handler is deregistered (generating one when registering
1032 is currently disabled). Drivers need to handle this correctly. Some
1033 don't and need to be caught.
1035 menu "Debug Oops, Lockups and Hangs"
1037 config PANIC_ON_OOPS
1038 bool "Panic on Oops"
1040 Say Y here to enable the kernel to panic when it oopses. This
1041 has the same effect as setting oops=panic on the kernel command
1044 This feature is useful to ensure that the kernel does not do
1045 anything erroneous after an oops which could result in data
1046 corruption or other issues.
1050 config PANIC_ON_OOPS_VALUE
1053 default 0 if !PANIC_ON_OOPS
1054 default 1 if PANIC_ON_OOPS
1056 config PANIC_TIMEOUT
1060 Set the timeout value (in seconds) until a reboot occurs when
1061 the kernel panics. If n = 0, then we wait forever. A timeout
1062 value n > 0 will wait n seconds before rebooting, while a timeout
1063 value n < 0 will reboot immediately.
1065 config LOCKUP_DETECTOR
1068 config SOFTLOCKUP_DETECTOR
1069 bool "Detect Soft Lockups"
1070 depends on DEBUG_KERNEL && !S390
1071 select LOCKUP_DETECTOR
1073 Say Y here to enable the kernel to act as a watchdog to detect
1076 Softlockups are bugs that cause the kernel to loop in kernel
1077 mode for more than 20 seconds, without giving other tasks a
1078 chance to run. The current stack trace is displayed upon
1079 detection and the system will stay locked up.
1081 config BOOTPARAM_SOFTLOCKUP_PANIC
1082 bool "Panic (Reboot) On Soft Lockups"
1083 depends on SOFTLOCKUP_DETECTOR
1085 Say Y here to enable the kernel to panic on "soft lockups",
1086 which are bugs that cause the kernel to loop in kernel
1087 mode for more than 20 seconds (configurable using the watchdog_thresh
1088 sysctl), without giving other tasks a chance to run.
1090 The panic can be used in combination with panic_timeout,
1091 to cause the system to reboot automatically after a
1092 lockup has been detected. This feature is useful for
1093 high-availability systems that have uptime guarantees and
1094 where a lockup must be resolved ASAP.
1098 config HARDLOCKUP_DETECTOR_PERF
1100 select SOFTLOCKUP_DETECTOR
1103 # Enables a timestamp based low pass filter to compensate for perf based
1104 # hard lockup detection which runs too fast due to turbo modes.
1106 config HARDLOCKUP_CHECK_TIMESTAMP
1110 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1111 # lockup detector rather than the perf based detector.
1113 config HARDLOCKUP_DETECTOR
1114 bool "Detect Hard Lockups"
1115 depends on DEBUG_KERNEL && !S390
1116 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1117 select LOCKUP_DETECTOR
1118 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1120 Say Y here to enable the kernel to act as a watchdog to detect
1123 Hardlockups are bugs that cause the CPU to loop in kernel mode
1124 for more than 10 seconds, without letting other interrupts have a
1125 chance to run. The current stack trace is displayed upon detection
1126 and the system will stay locked up.
1128 config BOOTPARAM_HARDLOCKUP_PANIC
1129 bool "Panic (Reboot) On Hard Lockups"
1130 depends on HARDLOCKUP_DETECTOR
1132 Say Y here to enable the kernel to panic on "hard lockups",
1133 which are bugs that cause the kernel to loop in kernel
1134 mode with interrupts disabled for more than 10 seconds (configurable
1135 using the watchdog_thresh sysctl).
1139 config DETECT_HUNG_TASK
1140 bool "Detect Hung Tasks"
1141 depends on DEBUG_KERNEL
1142 default SOFTLOCKUP_DETECTOR
1144 Say Y here to enable the kernel to detect "hung tasks",
1145 which are bugs that cause the task to be stuck in
1146 uninterruptible "D" state indefinitely.
1148 When a hung task is detected, the kernel will print the
1149 current stack trace (which you should report), but the
1150 task will stay in uninterruptible state. If lockdep is
1151 enabled then all held locks will also be reported. This
1152 feature has negligible overhead.
1154 config DEFAULT_HUNG_TASK_TIMEOUT
1155 int "Default timeout for hung task detection (in seconds)"
1156 depends on DETECT_HUNG_TASK
1159 This option controls the default timeout (in seconds) used
1160 to determine when a task has become non-responsive and should
1163 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1164 sysctl or by writing a value to
1165 /proc/sys/kernel/hung_task_timeout_secs.
1167 A timeout of 0 disables the check. The default is two minutes.
1168 Keeping the default should be fine in most cases.
1170 config BOOTPARAM_HUNG_TASK_PANIC
1171 bool "Panic (Reboot) On Hung Tasks"
1172 depends on DETECT_HUNG_TASK
1174 Say Y here to enable the kernel to panic on "hung tasks",
1175 which are bugs that cause the kernel to leave a task stuck
1176 in uninterruptible "D" state.
1178 The panic can be used in combination with panic_timeout,
1179 to cause the system to reboot automatically after a
1180 hung task has been detected. This feature is useful for
1181 high-availability systems that have uptime guarantees and
1182 where a hung tasks must be resolved ASAP.
1187 bool "Detect Workqueue Stalls"
1188 depends on DEBUG_KERNEL
1190 Say Y here to enable stall detection on workqueues. If a
1191 worker pool doesn't make forward progress on a pending work
1192 item for over a given amount of time, 30s by default, a
1193 warning message is printed along with dump of workqueue
1194 state. This can be configured through kernel parameter
1195 "workqueue.watchdog_thresh" and its sysfs counterpart.
1198 tristate "Test module to generate lockups"
1201 This builds the "test_lockup" module that helps to make sure
1202 that watchdogs and lockup detectors are working properly.
1204 Depending on module parameters it could emulate soft or hard
1205 lockup, "hung task", or locking arbitrary lock for a long time.
1206 Also it could generate series of lockups with cooling-down periods.
1210 endmenu # "Debug lockups and hangs"
1212 menu "Scheduler Debugging"
1215 bool "Collect scheduler debugging info"
1216 depends on DEBUG_KERNEL && PROC_FS
1219 If you say Y here, the /proc/sched_debug file will be provided
1220 that can help debug the scheduler. The runtime overhead of this
1228 bool "Collect scheduler statistics"
1229 depends on DEBUG_KERNEL && PROC_FS
1232 If you say Y here, additional code will be inserted into the
1233 scheduler and related routines to collect statistics about
1234 scheduler behavior and provide them in /proc/schedstat. These
1235 stats may be useful for both tuning and debugging the scheduler
1236 If you aren't debugging the scheduler or trying to tune a specific
1237 application, you can say N to avoid the very slight overhead
1242 config DEBUG_TIMEKEEPING
1243 bool "Enable extra timekeeping sanity checking"
1245 This option will enable additional timekeeping sanity checks
1246 which may be helpful when diagnosing issues where timekeeping
1247 problems are suspected.
1249 This may include checks in the timekeeping hotpaths, so this
1250 option may have a (very small) performance impact to some
1255 config DEBUG_PREEMPT
1256 bool "Debug preemptible kernel"
1257 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1260 If you say Y here then the kernel will use a debug variant of the
1261 commonly used smp_processor_id() function and will print warnings
1262 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1263 will detect preemption count underflows.
1265 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1267 config LOCK_DEBUGGING_SUPPORT
1269 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1272 config PROVE_LOCKING
1273 bool "Lock debugging: prove locking correctness"
1274 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1276 select DEBUG_SPINLOCK
1277 select DEBUG_MUTEXES if !PREEMPT_RT
1278 select DEBUG_RT_MUTEXES if RT_MUTEXES
1280 select DEBUG_WW_MUTEX_SLOWPATH
1281 select DEBUG_LOCK_ALLOC
1282 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1283 select TRACE_IRQFLAGS
1286 This feature enables the kernel to prove that all locking
1287 that occurs in the kernel runtime is mathematically
1288 correct: that under no circumstance could an arbitrary (and
1289 not yet triggered) combination of observed locking
1290 sequences (on an arbitrary number of CPUs, running an
1291 arbitrary number of tasks and interrupt contexts) cause a
1294 In short, this feature enables the kernel to report locking
1295 related deadlocks before they actually occur.
1297 The proof does not depend on how hard and complex a
1298 deadlock scenario would be to trigger: how many
1299 participant CPUs, tasks and irq-contexts would be needed
1300 for it to trigger. The proof also does not depend on
1301 timing: if a race and a resulting deadlock is possible
1302 theoretically (no matter how unlikely the race scenario
1303 is), it will be proven so and will immediately be
1304 reported by the kernel (once the event is observed that
1305 makes the deadlock theoretically possible).
1307 If a deadlock is impossible (i.e. the locking rules, as
1308 observed by the kernel, are mathematically correct), the
1309 kernel reports nothing.
1311 NOTE: this feature can also be enabled for rwlocks, mutexes
1312 and rwsems - in which case all dependencies between these
1313 different locking variants are observed and mapped too, and
1314 the proof of observed correctness is also maintained for an
1315 arbitrary combination of these separate locking variants.
1317 For more details, see Documentation/locking/lockdep-design.rst.
1319 config PROVE_RAW_LOCK_NESTING
1320 bool "Enable raw_spinlock - spinlock nesting checks"
1321 depends on PROVE_LOCKING
1324 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1325 that the lock nesting rules for PREEMPT_RT enabled kernels are
1328 NOTE: There are known nesting problems. So if you enable this
1329 option expect lockdep splats until these problems have been fully
1330 addressed which is work in progress. This config switch allows to
1331 identify and analyze these problems. It will be removed and the
1332 check permanently enabled once the main issues have been fixed.
1334 If unsure, select N.
1337 bool "Lock usage statistics"
1338 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1340 select DEBUG_SPINLOCK
1341 select DEBUG_MUTEXES if !PREEMPT_RT
1342 select DEBUG_RT_MUTEXES if RT_MUTEXES
1343 select DEBUG_LOCK_ALLOC
1346 This feature enables tracking lock contention points
1348 For more details, see Documentation/locking/lockstat.rst
1350 This also enables lock events required by "perf lock",
1352 If you want to use "perf lock", you also need to turn on
1353 CONFIG_EVENT_TRACING.
1355 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1356 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1358 config DEBUG_RT_MUTEXES
1359 bool "RT Mutex debugging, deadlock detection"
1360 depends on DEBUG_KERNEL && RT_MUTEXES
1362 This allows rt mutex semantics violations and rt mutex related
1363 deadlocks (lockups) to be detected and reported automatically.
1365 config DEBUG_SPINLOCK
1366 bool "Spinlock and rw-lock debugging: basic checks"
1367 depends on DEBUG_KERNEL
1368 select UNINLINE_SPIN_UNLOCK
1370 Say Y here and build SMP to catch missing spinlock initialization
1371 and certain other kinds of spinlock errors commonly made. This is
1372 best used in conjunction with the NMI watchdog so that spinlock
1373 deadlocks are also debuggable.
1375 config DEBUG_MUTEXES
1376 bool "Mutex debugging: basic checks"
1377 depends on DEBUG_KERNEL && !PREEMPT_RT
1379 This feature allows mutex semantics violations to be detected and
1382 config DEBUG_WW_MUTEX_SLOWPATH
1383 bool "Wait/wound mutex debugging: Slowpath testing"
1384 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1385 select DEBUG_LOCK_ALLOC
1386 select DEBUG_SPINLOCK
1387 select DEBUG_MUTEXES if !PREEMPT_RT
1388 select DEBUG_RT_MUTEXES if PREEMPT_RT
1390 This feature enables slowpath testing for w/w mutex users by
1391 injecting additional -EDEADLK wound/backoff cases. Together with
1392 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1393 will test all possible w/w mutex interface abuse with the
1394 exception of simply not acquiring all the required locks.
1395 Note that this feature can introduce significant overhead, so
1396 it really should not be enabled in a production or distro kernel,
1397 even a debug kernel. If you are a driver writer, enable it. If
1398 you are a distro, do not.
1401 bool "RW Semaphore debugging: basic checks"
1402 depends on DEBUG_KERNEL
1404 This debugging feature allows mismatched rw semaphore locks
1405 and unlocks to be detected and reported.
1407 config DEBUG_LOCK_ALLOC
1408 bool "Lock debugging: detect incorrect freeing of live locks"
1409 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1410 select DEBUG_SPINLOCK
1411 select DEBUG_MUTEXES if !PREEMPT_RT
1412 select DEBUG_RT_MUTEXES if RT_MUTEXES
1415 This feature will check whether any held lock (spinlock, rwlock,
1416 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1417 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1418 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1419 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1420 held during task exit.
1424 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1429 config LOCKDEP_SMALL
1433 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1434 depends on LOCKDEP && !LOCKDEP_SMALL
1438 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1440 config LOCKDEP_CHAINS_BITS
1441 int "Bitsize for MAX_LOCKDEP_CHAINS"
1442 depends on LOCKDEP && !LOCKDEP_SMALL
1446 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1448 config LOCKDEP_STACK_TRACE_BITS
1449 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1450 depends on LOCKDEP && !LOCKDEP_SMALL
1454 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1456 config LOCKDEP_STACK_TRACE_HASH_BITS
1457 int "Bitsize for STACK_TRACE_HASH_SIZE"
1458 depends on LOCKDEP && !LOCKDEP_SMALL
1462 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1464 config LOCKDEP_CIRCULAR_QUEUE_BITS
1465 int "Bitsize for elements in circular_queue struct"
1470 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1472 config DEBUG_LOCKDEP
1473 bool "Lock dependency engine debugging"
1474 depends on DEBUG_KERNEL && LOCKDEP
1475 select DEBUG_IRQFLAGS
1477 If you say Y here, the lock dependency engine will do
1478 additional runtime checks to debug itself, at the price
1479 of more runtime overhead.
1481 config DEBUG_ATOMIC_SLEEP
1482 bool "Sleep inside atomic section checking"
1483 select PREEMPT_COUNT
1484 depends on DEBUG_KERNEL
1485 depends on !ARCH_NO_PREEMPT
1487 If you say Y here, various routines which may sleep will become very
1488 noisy if they are called inside atomic sections: when a spinlock is
1489 held, inside an rcu read side critical section, inside preempt disabled
1490 sections, inside an interrupt, etc...
1492 config DEBUG_LOCKING_API_SELFTESTS
1493 bool "Locking API boot-time self-tests"
1494 depends on DEBUG_KERNEL
1496 Say Y here if you want the kernel to run a short self-test during
1497 bootup. The self-test checks whether common types of locking bugs
1498 are detected by debugging mechanisms or not. (if you disable
1499 lock debugging then those bugs won't be detected of course.)
1500 The following locking APIs are covered: spinlocks, rwlocks,
1503 config LOCK_TORTURE_TEST
1504 tristate "torture tests for locking"
1505 depends on DEBUG_KERNEL
1508 This option provides a kernel module that runs torture tests
1509 on kernel locking primitives. The kernel module may be built
1510 after the fact on the running kernel to be tested, if desired.
1512 Say Y here if you want kernel locking-primitive torture tests
1513 to be built into the kernel.
1514 Say M if you want these torture tests to build as a module.
1515 Say N if you are unsure.
1517 config WW_MUTEX_SELFTEST
1518 tristate "Wait/wound mutex selftests"
1520 This option provides a kernel module that runs tests on the
1521 on the struct ww_mutex locking API.
1523 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1524 with this test harness.
1526 Say M if you want these self tests to build as a module.
1527 Say N if you are unsure.
1529 config SCF_TORTURE_TEST
1530 tristate "torture tests for smp_call_function*()"
1531 depends on DEBUG_KERNEL
1534 This option provides a kernel module that runs torture tests
1535 on the smp_call_function() family of primitives. The kernel
1536 module may be built after the fact on the running kernel to
1537 be tested, if desired.
1539 config CSD_LOCK_WAIT_DEBUG
1540 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1541 depends on DEBUG_KERNEL
1545 This option enables debug prints when CPUs are slow to respond
1546 to the smp_call_function*() IPI wrappers. These debug prints
1547 include the IPI handler function currently executing (if any)
1548 and relevant stack traces.
1550 endmenu # lock debugging
1552 config TRACE_IRQFLAGS
1553 depends on TRACE_IRQFLAGS_SUPPORT
1556 Enables hooks to interrupt enabling and disabling for
1557 either tracing or lock debugging.
1559 config TRACE_IRQFLAGS_NMI
1561 depends on TRACE_IRQFLAGS
1562 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1564 config DEBUG_IRQFLAGS
1565 bool "Debug IRQ flag manipulation"
1567 Enables checks for potentially unsafe enabling or disabling of
1568 interrupts, such as calling raw_local_irq_restore() when interrupts
1572 bool "Stack backtrace support"
1573 depends on STACKTRACE_SUPPORT
1575 This option causes the kernel to create a /proc/pid/stack for
1576 every process, showing its current stack trace.
1577 It is also used by various kernel debugging features that require
1578 stack trace generation.
1580 config WARN_ALL_UNSEEDED_RANDOM
1581 bool "Warn for all uses of unseeded randomness"
1584 Some parts of the kernel contain bugs relating to their use of
1585 cryptographically secure random numbers before it's actually possible
1586 to generate those numbers securely. This setting ensures that these
1587 flaws don't go unnoticed, by enabling a message, should this ever
1588 occur. This will allow people with obscure setups to know when things
1589 are going wrong, so that they might contact developers about fixing
1592 Unfortunately, on some models of some architectures getting
1593 a fully seeded CRNG is extremely difficult, and so this can
1594 result in dmesg getting spammed for a surprisingly long
1595 time. This is really bad from a security perspective, and
1596 so architecture maintainers really need to do what they can
1597 to get the CRNG seeded sooner after the system is booted.
1598 However, since users cannot do anything actionable to
1599 address this, by default this option is disabled.
1601 Say Y here if you want to receive warnings for all uses of
1602 unseeded randomness. This will be of use primarily for
1603 those developers interested in improving the security of
1604 Linux kernels running on their architecture (or
1607 config DEBUG_KOBJECT
1608 bool "kobject debugging"
1609 depends on DEBUG_KERNEL
1611 If you say Y here, some extra kobject debugging messages will be sent
1614 config DEBUG_KOBJECT_RELEASE
1615 bool "kobject release debugging"
1616 depends on DEBUG_OBJECTS_TIMERS
1618 kobjects are reference counted objects. This means that their
1619 last reference count put is not predictable, and the kobject can
1620 live on past the point at which a driver decides to drop its
1621 initial reference to the kobject gained on allocation. An
1622 example of this would be a struct device which has just been
1625 However, some buggy drivers assume that after such an operation,
1626 the memory backing the kobject can be immediately freed. This
1627 goes completely against the principles of a refcounted object.
1629 If you say Y here, the kernel will delay the release of kobjects
1630 on the last reference count to improve the visibility of this
1631 kind of kobject release bug.
1633 config HAVE_DEBUG_BUGVERBOSE
1636 menu "Debug kernel data structures"
1639 bool "Debug linked list manipulation"
1640 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1642 Enable this to turn on extended checks in the linked-list
1648 bool "Debug priority linked list manipulation"
1649 depends on DEBUG_KERNEL
1651 Enable this to turn on extended checks in the priority-ordered
1652 linked-list (plist) walking routines. This checks the entire
1653 list multiple times during each manipulation.
1658 bool "Debug SG table operations"
1659 depends on DEBUG_KERNEL
1661 Enable this to turn on checks on scatter-gather tables. This can
1662 help find problems with drivers that do not properly initialize
1667 config DEBUG_NOTIFIERS
1668 bool "Debug notifier call chains"
1669 depends on DEBUG_KERNEL
1671 Enable this to turn on sanity checking for notifier call chains.
1672 This is most useful for kernel developers to make sure that
1673 modules properly unregister themselves from notifier chains.
1674 This is a relatively cheap check but if you care about maximum
1677 config BUG_ON_DATA_CORRUPTION
1678 bool "Trigger a BUG when data corruption is detected"
1681 Select this option if the kernel should BUG when it encounters
1682 data corruption in kernel memory structures when they get checked
1687 config DEBUG_MAPLE_TREE
1688 bool "Debug maple trees"
1689 depends on DEBUG_KERNEL
1691 Enable maple tree debugging information and extra validations.
1697 config DEBUG_CREDENTIALS
1698 bool "Debug credential management"
1699 depends on DEBUG_KERNEL
1701 Enable this to turn on some debug checking for credential
1702 management. The additional code keeps track of the number of
1703 pointers from task_structs to any given cred struct, and checks to
1704 see that this number never exceeds the usage count of the cred
1707 Furthermore, if SELinux is enabled, this also checks that the
1708 security pointer in the cred struct is never seen to be invalid.
1712 source "kernel/rcu/Kconfig.debug"
1714 config DEBUG_WQ_FORCE_RR_CPU
1715 bool "Force round-robin CPU selection for unbound work items"
1716 depends on DEBUG_KERNEL
1719 Workqueue used to implicitly guarantee that work items queued
1720 without explicit CPU specified are put on the local CPU. This
1721 guarantee is no longer true and while local CPU is still
1722 preferred work items may be put on foreign CPUs. Kernel
1723 parameter "workqueue.debug_force_rr_cpu" is added to force
1724 round-robin CPU selection to flush out usages which depend on the
1725 now broken guarantee. This config option enables the debug
1726 feature by default. When enabled, memory and cache locality will
1729 config CPU_HOTPLUG_STATE_CONTROL
1730 bool "Enable CPU hotplug state control"
1731 depends on DEBUG_KERNEL
1732 depends on HOTPLUG_CPU
1735 Allows to write steps between "offline" and "online" to the CPUs
1736 sysfs target file so states can be stepped granular. This is a debug
1737 option for now as the hotplug machinery cannot be stopped and
1738 restarted at arbitrary points yet.
1740 Say N if your are unsure.
1743 bool "Latency measuring infrastructure"
1744 depends on DEBUG_KERNEL
1745 depends on STACKTRACE_SUPPORT
1747 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1753 Enable this option if you want to use the LatencyTOP tool
1754 to find out which userspace is blocking on what kernel operations.
1756 config DEBUG_CGROUP_REF
1757 bool "Disable inlining of cgroup css reference count functions"
1758 depends on DEBUG_KERNEL
1763 Force cgroup css reference count functions to not be inlined so
1764 that they can be kprobed for debugging.
1766 source "kernel/trace/Kconfig"
1768 config PROVIDE_OHCI1394_DMA_INIT
1769 bool "Remote debugging over FireWire early on boot"
1770 depends on PCI && X86
1772 If you want to debug problems which hang or crash the kernel early
1773 on boot and the crashing machine has a FireWire port, you can use
1774 this feature to remotely access the memory of the crashed machine
1775 over FireWire. This employs remote DMA as part of the OHCI1394
1776 specification which is now the standard for FireWire controllers.
1778 With remote DMA, you can monitor the printk buffer remotely using
1779 firescope and access all memory below 4GB using fireproxy from gdb.
1780 Even controlling a kernel debugger is possible using remote DMA.
1784 If ohci1394_dma=early is used as boot parameter, it will initialize
1785 all OHCI1394 controllers which are found in the PCI config space.
1787 As all changes to the FireWire bus such as enabling and disabling
1788 devices cause a bus reset and thereby disable remote DMA for all
1789 devices, be sure to have the cable plugged and FireWire enabled on
1790 the debugging host before booting the debug target for debugging.
1792 This code (~1k) is freed after boot. By then, the firewire stack
1793 in charge of the OHCI-1394 controllers should be used instead.
1795 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1797 source "samples/Kconfig"
1799 config ARCH_HAS_DEVMEM_IS_ALLOWED
1802 config STRICT_DEVMEM
1803 bool "Filter access to /dev/mem"
1804 depends on MMU && DEVMEM
1805 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1806 default y if PPC || X86 || ARM64
1808 If this option is disabled, you allow userspace (root) access to all
1809 of memory, including kernel and userspace memory. Accidental
1810 access to this is obviously disastrous, but specific access can
1811 be used by people debugging the kernel. Note that with PAT support
1812 enabled, even in this case there are restrictions on /dev/mem
1813 use due to the cache aliasing requirements.
1815 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1816 file only allows userspace access to PCI space and the BIOS code and
1817 data regions. This is sufficient for dosemu and X and all common
1822 config IO_STRICT_DEVMEM
1823 bool "Filter I/O access to /dev/mem"
1824 depends on STRICT_DEVMEM
1826 If this option is disabled, you allow userspace (root) access to all
1827 io-memory regardless of whether a driver is actively using that
1828 range. Accidental access to this is obviously disastrous, but
1829 specific access can be used by people debugging kernel drivers.
1831 If this option is switched on, the /dev/mem file only allows
1832 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1833 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1834 if the driver using a given range cannot be disabled.
1838 menu "$(SRCARCH) Debugging"
1840 source "arch/$(SRCARCH)/Kconfig.debug"
1844 menu "Kernel Testing and Coverage"
1846 source "lib/kunit/Kconfig"
1848 config NOTIFIER_ERROR_INJECTION
1849 tristate "Notifier error injection"
1850 depends on DEBUG_KERNEL
1853 This option provides the ability to inject artificial errors to
1854 specified notifier chain callbacks. It is useful to test the error
1855 handling of notifier call chain failures.
1859 config PM_NOTIFIER_ERROR_INJECT
1860 tristate "PM notifier error injection module"
1861 depends on PM && NOTIFIER_ERROR_INJECTION
1862 default m if PM_DEBUG
1864 This option provides the ability to inject artificial errors to
1865 PM notifier chain callbacks. It is controlled through debugfs
1866 interface /sys/kernel/debug/notifier-error-inject/pm
1868 If the notifier call chain should be failed with some events
1869 notified, write the error code to "actions/<notifier event>/error".
1871 Example: Inject PM suspend error (-12 = -ENOMEM)
1873 # cd /sys/kernel/debug/notifier-error-inject/pm/
1874 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1875 # echo mem > /sys/power/state
1876 bash: echo: write error: Cannot allocate memory
1878 To compile this code as a module, choose M here: the module will
1879 be called pm-notifier-error-inject.
1883 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1884 tristate "OF reconfig notifier error injection module"
1885 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1887 This option provides the ability to inject artificial errors to
1888 OF reconfig notifier chain callbacks. It is controlled
1889 through debugfs interface under
1890 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1892 If the notifier call chain should be failed with some events
1893 notified, write the error code to "actions/<notifier event>/error".
1895 To compile this code as a module, choose M here: the module will
1896 be called of-reconfig-notifier-error-inject.
1900 config NETDEV_NOTIFIER_ERROR_INJECT
1901 tristate "Netdev notifier error injection module"
1902 depends on NET && NOTIFIER_ERROR_INJECTION
1904 This option provides the ability to inject artificial errors to
1905 netdevice notifier chain callbacks. It is controlled through debugfs
1906 interface /sys/kernel/debug/notifier-error-inject/netdev
1908 If the notifier call chain should be failed with some events
1909 notified, write the error code to "actions/<notifier event>/error".
1911 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1913 # cd /sys/kernel/debug/notifier-error-inject/netdev
1914 # echo -22 > actions/NETDEV_CHANGEMTU/error
1915 # ip link set eth0 mtu 1024
1916 RTNETLINK answers: Invalid argument
1918 To compile this code as a module, choose M here: the module will
1919 be called netdev-notifier-error-inject.
1923 config FUNCTION_ERROR_INJECTION
1924 bool "Fault-injections of functions"
1925 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1927 Add fault injections into various functions that are annotated with
1928 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
1929 value of these functions. This is useful to test error paths of code.
1933 config FAULT_INJECTION
1934 bool "Fault-injection framework"
1935 depends on DEBUG_KERNEL
1937 Provide fault-injection framework.
1938 For more details, see Documentation/fault-injection/.
1941 bool "Fault-injection capability for kmalloc"
1942 depends on FAULT_INJECTION
1943 depends on SLAB || SLUB
1945 Provide fault-injection capability for kmalloc.
1947 config FAIL_PAGE_ALLOC
1948 bool "Fault-injection capability for alloc_pages()"
1949 depends on FAULT_INJECTION
1951 Provide fault-injection capability for alloc_pages().
1953 config FAULT_INJECTION_USERCOPY
1954 bool "Fault injection capability for usercopy functions"
1955 depends on FAULT_INJECTION
1957 Provides fault-injection capability to inject failures
1958 in usercopy functions (copy_from_user(), get_user(), ...).
1960 config FAIL_MAKE_REQUEST
1961 bool "Fault-injection capability for disk IO"
1962 depends on FAULT_INJECTION && BLOCK
1964 Provide fault-injection capability for disk IO.
1966 config FAIL_IO_TIMEOUT
1967 bool "Fault-injection capability for faking disk interrupts"
1968 depends on FAULT_INJECTION && BLOCK
1970 Provide fault-injection capability on end IO handling. This
1971 will make the block layer "forget" an interrupt as configured,
1972 thus exercising the error handling.
1974 Only works with drivers that use the generic timeout handling,
1975 for others it won't do anything.
1978 bool "Fault-injection capability for futexes"
1980 depends on FAULT_INJECTION && FUTEX
1982 Provide fault-injection capability for futexes.
1984 config FAULT_INJECTION_DEBUG_FS
1985 bool "Debugfs entries for fault-injection capabilities"
1986 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1988 Enable configuration of fault-injection capabilities via debugfs.
1990 config FAIL_FUNCTION
1991 bool "Fault-injection capability for functions"
1992 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1994 Provide function-based fault-injection capability.
1995 This will allow you to override a specific function with a return
1996 with given return value. As a result, function caller will see
1997 an error value and have to handle it. This is useful to test the
1998 error handling in various subsystems.
2000 config FAIL_MMC_REQUEST
2001 bool "Fault-injection capability for MMC IO"
2002 depends on FAULT_INJECTION_DEBUG_FS && MMC
2004 Provide fault-injection capability for MMC IO.
2005 This will make the mmc core return data errors. This is
2006 useful to test the error handling in the mmc block device
2007 and to test how the mmc host driver handles retries from
2011 bool "Fault-injection capability for SunRPC"
2012 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2014 Provide fault-injection capability for SunRPC and
2017 config FAULT_INJECTION_STACKTRACE_FILTER
2018 bool "stacktrace filter for fault-injection capabilities"
2019 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
2021 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2023 Provide stacktrace filter for fault-injection capabilities
2025 config ARCH_HAS_KCOV
2028 An architecture should select this when it can successfully
2029 build and run with CONFIG_KCOV. This typically requires
2030 disabling instrumentation for some early boot code.
2032 config CC_HAS_SANCOV_TRACE_PC
2033 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2037 bool "Code coverage for fuzzing"
2038 depends on ARCH_HAS_KCOV
2039 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2040 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2041 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
2043 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2044 select OBJTOOL if HAVE_NOINSTR_HACK
2046 KCOV exposes kernel code coverage information in a form suitable
2047 for coverage-guided fuzzing (randomized testing).
2049 If RANDOMIZE_BASE is enabled, PC values will not be stable across
2050 different machines and across reboots. If you need stable PC values,
2051 disable RANDOMIZE_BASE.
2053 For more details, see Documentation/dev-tools/kcov.rst.
2055 config KCOV_ENABLE_COMPARISONS
2056 bool "Enable comparison operands collection by KCOV"
2058 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2060 KCOV also exposes operands of every comparison in the instrumented
2061 code along with operand sizes and PCs of the comparison instructions.
2062 These operands can be used by fuzzing engines to improve the quality
2063 of fuzzing coverage.
2065 config KCOV_INSTRUMENT_ALL
2066 bool "Instrument all code by default"
2070 If you are doing generic system call fuzzing (like e.g. syzkaller),
2071 then you will want to instrument the whole kernel and you should
2072 say y here. If you are doing more targeted fuzzing (like e.g.
2073 filesystem fuzzing with AFL) then you will want to enable coverage
2074 for more specific subsets of files, and should say n here.
2076 config KCOV_IRQ_AREA_SIZE
2077 hex "Size of interrupt coverage collection area in words"
2081 KCOV uses preallocated per-cpu areas to collect coverage from
2082 soft interrupts. This specifies the size of those areas in the
2083 number of unsigned long words.
2085 menuconfig RUNTIME_TESTING_MENU
2086 bool "Runtime Testing"
2089 if RUNTIME_TESTING_MENU
2092 tristate "Linux Kernel Dump Test Tool Module"
2095 This module enables testing of the different dumping mechanisms by
2096 inducing system failures at predefined crash points.
2097 If you don't need it: say N
2098 Choose M here to compile this code as a module. The module will be
2101 Documentation on how to use the module can be found in
2102 Documentation/fault-injection/provoke-crashes.rst
2104 config CPUMASK_KUNIT_TEST
2105 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2107 default KUNIT_ALL_TESTS
2109 Enable to turn on cpumask tests, running at boot or module load time.
2111 For more information on KUnit and unit tests in general, please refer
2112 to the KUnit documentation in Documentation/dev-tools/kunit/.
2116 config TEST_LIST_SORT
2117 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2119 default KUNIT_ALL_TESTS
2121 Enable this to turn on 'list_sort()' function test. This test is
2122 executed only once during system boot (so affects only boot time),
2123 or at module load time.
2127 config TEST_MIN_HEAP
2128 tristate "Min heap test"
2129 depends on DEBUG_KERNEL || m
2131 Enable this to turn on min heap function tests. This test is
2132 executed only once during system boot (so affects only boot time),
2133 or at module load time.
2138 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2140 default KUNIT_ALL_TESTS
2142 This option enables the self-test function of 'sort()' at boot,
2143 or at module load time.
2148 tristate "64bit/32bit division and modulo test"
2149 depends on DEBUG_KERNEL || m
2151 Enable this to turn on 'do_div()' function test. This test is
2152 executed only once during system boot (so affects only boot time),
2153 or at module load time.
2157 config KPROBES_SANITY_TEST
2158 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2159 depends on DEBUG_KERNEL
2162 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2163 default KUNIT_ALL_TESTS
2165 This option provides for testing basic kprobes functionality on
2166 boot. Samples of kprobe and kretprobe are inserted and
2167 verified for functionality.
2169 Say N if you are unsure.
2171 config FPROBE_SANITY_TEST
2172 bool "Self test for fprobe"
2173 depends on DEBUG_KERNEL
2177 This option will enable testing the fprobe when the system boot.
2178 A series of tests are made to verify that the fprobe is functioning
2181 Say N if you are unsure.
2183 config BACKTRACE_SELF_TEST
2184 tristate "Self test for the backtrace code"
2185 depends on DEBUG_KERNEL
2187 This option provides a kernel module that can be used to test
2188 the kernel stack backtrace code. This option is not useful
2189 for distributions or general kernels, but only for kernel
2190 developers working on architecture code.
2192 Note that if you want to also test saved backtraces, you will
2193 have to enable STACKTRACE as well.
2195 Say N if you are unsure.
2197 config TEST_REF_TRACKER
2198 tristate "Self test for reference tracker"
2199 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2202 This option provides a kernel module performing tests
2203 using reference tracker infrastructure.
2205 Say N if you are unsure.
2208 tristate "Red-Black tree test"
2209 depends on DEBUG_KERNEL
2211 A benchmark measuring the performance of the rbtree library.
2212 Also includes rbtree invariant checks.
2214 config REED_SOLOMON_TEST
2215 tristate "Reed-Solomon library test"
2216 depends on DEBUG_KERNEL || m
2218 select REED_SOLOMON_ENC16
2219 select REED_SOLOMON_DEC16
2221 This option enables the self-test function of rslib at boot,
2222 or at module load time.
2226 config INTERVAL_TREE_TEST
2227 tristate "Interval tree test"
2228 depends on DEBUG_KERNEL
2229 select INTERVAL_TREE
2231 A benchmark measuring the performance of the interval tree library
2234 tristate "Per cpu operations test"
2235 depends on m && DEBUG_KERNEL
2237 Enable this option to build test module which validates per-cpu
2242 config ATOMIC64_SELFTEST
2243 tristate "Perform an atomic64_t self-test"
2245 Enable this option to test the atomic64_t functions at boot or
2246 at module load time.
2250 config ASYNC_RAID6_TEST
2251 tristate "Self test for hardware accelerated raid6 recovery"
2252 depends on ASYNC_RAID6_RECOV
2255 This is a one-shot self test that permutes through the
2256 recovery of all the possible two disk failure scenarios for a
2257 N-disk array. Recovery is performed with the asynchronous
2258 raid6 recovery routines, and will optionally use an offload
2259 engine if one is available.
2264 tristate "Test functions located in the hexdump module at runtime"
2266 config STRING_SELFTEST
2267 tristate "Test string functions at runtime"
2269 config TEST_STRING_HELPERS
2270 tristate "Test functions located in the string_helpers module at runtime"
2273 tristate "Test kstrto*() family of functions at runtime"
2276 tristate "Test printf() family of functions at runtime"
2279 tristate "Test scanf() family of functions at runtime"
2282 tristate "Test bitmap_*() family of functions at runtime"
2284 Enable this option to test the bitmap functions at boot.
2289 tristate "Test functions located in the uuid module at runtime"
2292 tristate "Test the XArray code at runtime"
2294 config TEST_MAPLE_TREE
2295 depends on DEBUG_KERNEL
2296 select DEBUG_MAPLE_TREE
2297 tristate "Test the Maple Tree code at runtime"
2299 config TEST_RHASHTABLE
2300 tristate "Perform selftest on resizable hash table"
2302 Enable this option to test the rhashtable functions at boot.
2307 tristate "Perform selftest on IDA functions"
2310 tristate "Perform selftest on priority array manager"
2313 Enable this option to test priority array manager on boot
2318 config TEST_IRQ_TIMINGS
2319 bool "IRQ timings selftest"
2320 depends on IRQ_TIMINGS
2322 Enable this option to test the irq timings code on boot.
2327 tristate "Test module loading with 'hello world' module"
2330 This builds the "test_module" module that emits "Hello, world"
2331 on printk when loaded. It is designed to be used for basic
2332 evaluation of the module loading subsystem (for example when
2333 validating module verification). It lacks any extra dependencies,
2334 and will not normally be loaded by the system unless explicitly
2340 tristate "Test module for compilation of bitops operations"
2343 This builds the "test_bitops" module that is much like the
2344 TEST_LKM module except that it does a basic exercise of the
2345 set/clear_bit macros and get_count_order/long to make sure there are
2346 no compiler warnings from C=1 sparse checker or -Wextra
2347 compilations. It has no dependencies and doesn't run or load unless
2348 explicitly requested by name. for example: modprobe test_bitops.
2353 tristate "Test module for stress/performance analysis of vmalloc allocator"
2358 This builds the "test_vmalloc" module that should be used for
2359 stress and performance analysis. So, any new change for vmalloc
2360 subsystem can be evaluated from performance and stability point
2365 config TEST_USER_COPY
2366 tristate "Test user/kernel boundary protections"
2369 This builds the "test_user_copy" module that runs sanity checks
2370 on the copy_to/from_user infrastructure, making sure basic
2371 user/kernel boundary testing is working. If it fails to load,
2372 a regression has been detected in the user/kernel memory boundary
2378 tristate "Test BPF filter functionality"
2381 This builds the "test_bpf" module that runs various test vectors
2382 against the BPF interpreter or BPF JIT compiler depending on the
2383 current setting. This is in particular useful for BPF JIT compiler
2384 development, but also to run regression tests against changes in
2385 the interpreter code. It also enables test stubs for eBPF maps and
2386 verifier used by user space verifier testsuite.
2390 config TEST_BLACKHOLE_DEV
2391 tristate "Test blackhole netdev functionality"
2394 This builds the "test_blackhole_dev" module that validates the
2395 data path through this blackhole netdev.
2399 config FIND_BIT_BENCHMARK
2400 tristate "Test find_bit functions"
2402 This builds the "test_find_bit" module that measure find_*_bit()
2403 functions performance.
2407 config TEST_FIRMWARE
2408 tristate "Test firmware loading via userspace interface"
2409 depends on FW_LOADER
2411 This builds the "test_firmware" module that creates a userspace
2412 interface for testing firmware loading. This can be used to
2413 control the triggering of firmware loading without needing an
2414 actual firmware-using device. The contents can be rechecked by
2420 tristate "sysctl test driver"
2421 depends on PROC_SYSCTL
2423 This builds the "test_sysctl" module. This driver enables to test the
2424 proc sysctl interfaces available to drivers safely without affecting
2425 production knobs which might alter system functionality.
2429 config BITFIELD_KUNIT
2430 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2432 default KUNIT_ALL_TESTS
2434 Enable this option to test the bitfield functions at boot.
2436 KUnit tests run during boot and output the results to the debug log
2437 in TAP format (http://testanything.org/). Only useful for kernel devs
2438 running the KUnit test harness, and not intended for inclusion into a
2441 For more information on KUnit and unit tests in general please refer
2442 to the KUnit documentation in Documentation/dev-tools/kunit/.
2446 config HASH_KUNIT_TEST
2447 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2449 default KUNIT_ALL_TESTS
2451 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2452 integer (<linux/hash.h>) hash functions on boot.
2454 KUnit tests run during boot and output the results to the debug log
2455 in TAP format (https://testanything.org/). Only useful for kernel devs
2456 running the KUnit test harness, and not intended for inclusion into a
2459 For more information on KUnit and unit tests in general please refer
2460 to the KUnit documentation in Documentation/dev-tools/kunit/.
2462 This is intended to help people writing architecture-specific
2463 optimized versions. If unsure, say N.
2465 config RESOURCE_KUNIT_TEST
2466 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2468 default KUNIT_ALL_TESTS
2470 This builds the resource API unit test.
2471 Tests the logic of API provided by resource.c and ioport.h.
2472 For more information on KUnit and unit tests in general please refer
2473 to the KUnit documentation in Documentation/dev-tools/kunit/.
2477 config SYSCTL_KUNIT_TEST
2478 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2480 default KUNIT_ALL_TESTS
2482 This builds the proc sysctl unit test, which runs on boot.
2483 Tests the API contract and implementation correctness of sysctl.
2484 For more information on KUnit and unit tests in general please refer
2485 to the KUnit documentation in Documentation/dev-tools/kunit/.
2489 config LIST_KUNIT_TEST
2490 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2492 default KUNIT_ALL_TESTS
2494 This builds the linked list KUnit test suite.
2495 It tests that the API and basic functionality of the list_head type
2496 and associated macros.
2498 KUnit tests run during boot and output the results to the debug log
2499 in TAP format (https://testanything.org/). Only useful for kernel devs
2500 running the KUnit test harness, and not intended for inclusion into a
2503 For more information on KUnit and unit tests in general please refer
2504 to the KUnit documentation in Documentation/dev-tools/kunit/.
2508 config LINEAR_RANGES_TEST
2509 tristate "KUnit test for linear_ranges"
2511 select LINEAR_RANGES
2513 This builds the linear_ranges unit test, which runs on boot.
2514 Tests the linear_ranges logic correctness.
2515 For more information on KUnit and unit tests in general please refer
2516 to the KUnit documentation in Documentation/dev-tools/kunit/.
2520 config CMDLINE_KUNIT_TEST
2521 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2523 default KUNIT_ALL_TESTS
2525 This builds the cmdline API unit test.
2526 Tests the logic of API provided by cmdline.c.
2527 For more information on KUnit and unit tests in general please refer
2528 to the KUnit documentation in Documentation/dev-tools/kunit/.
2533 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2535 default KUNIT_ALL_TESTS
2537 This builds the bits unit test.
2538 Tests the logic of macros defined in bits.h.
2539 For more information on KUnit and unit tests in general please refer
2540 to the KUnit documentation in Documentation/dev-tools/kunit/.
2544 config SLUB_KUNIT_TEST
2545 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2546 depends on SLUB_DEBUG && KUNIT
2547 default KUNIT_ALL_TESTS
2549 This builds SLUB allocator unit test.
2550 Tests SLUB cache debugging functionality.
2551 For more information on KUnit and unit tests in general please refer
2552 to the KUnit documentation in Documentation/dev-tools/kunit/.
2556 config RATIONAL_KUNIT_TEST
2557 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2558 depends on KUNIT && RATIONAL
2559 default KUNIT_ALL_TESTS
2561 This builds the rational math unit test.
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 MEMCPY_KUNIT_TEST
2568 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2570 default KUNIT_ALL_TESTS
2572 Builds unit tests for memcpy(), memmove(), and memset() functions.
2573 For more information on KUnit and unit tests in general please refer
2574 to the KUnit documentation in Documentation/dev-tools/kunit/.
2578 config MEMCPY_SLOW_KUNIT_TEST
2579 bool "Include exhaustive memcpy tests"
2580 depends on MEMCPY_KUNIT_TEST
2583 Some memcpy tests are quite exhaustive in checking for overlaps
2584 and bit ranges. These can be very slow, so they are split out
2585 as a separate config, in case they need to be disabled.
2587 config IS_SIGNED_TYPE_KUNIT_TEST
2588 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2590 default KUNIT_ALL_TESTS
2592 Builds unit tests for the is_signed_type() macro.
2594 For more information on KUnit and unit tests in general please refer
2595 to the KUnit documentation in Documentation/dev-tools/kunit/.
2599 config OVERFLOW_KUNIT_TEST
2600 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2602 default KUNIT_ALL_TESTS
2604 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2607 For more information on KUnit and unit tests in general please refer
2608 to the KUnit documentation in Documentation/dev-tools/kunit/.
2612 config STACKINIT_KUNIT_TEST
2613 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2615 default KUNIT_ALL_TESTS
2617 Test if the kernel is zero-initializing stack variables and
2618 padding. Coverage is controlled by compiler flags,
2619 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2620 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2621 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2623 config FORTIFY_KUNIT_TEST
2624 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2625 depends on KUNIT && FORTIFY_SOURCE
2626 default KUNIT_ALL_TESTS
2628 Builds unit tests for checking internals of FORTIFY_SOURCE as used
2629 by the str*() and mem*() family of functions. For testing runtime
2630 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2632 config HW_BREAKPOINT_KUNIT_TEST
2633 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2634 depends on HAVE_HW_BREAKPOINT
2636 default KUNIT_ALL_TESTS
2638 Tests for hw_breakpoint constraints accounting.
2642 config STRSCPY_KUNIT_TEST
2643 tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS
2645 default KUNIT_ALL_TESTS
2647 config SIPHASH_KUNIT_TEST
2648 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2650 default KUNIT_ALL_TESTS
2652 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2653 functions on boot (or module load).
2655 This is intended to help people writing architecture-specific
2656 optimized versions. If unsure, say N.
2659 tristate "udelay test driver"
2661 This builds the "udelay_test" module that helps to make sure
2662 that udelay() is working properly.
2666 config TEST_STATIC_KEYS
2667 tristate "Test static keys"
2670 Test the static key interfaces.
2674 config TEST_DYNAMIC_DEBUG
2675 tristate "Test DYNAMIC_DEBUG"
2676 depends on DYNAMIC_DEBUG
2678 This module registers a tracer callback to count enabled
2679 pr_debugs in a 'do_debugging' function, then alters their
2680 enablements, calls the function, and compares counts.
2685 tristate "kmod stress tester"
2687 depends on NETDEVICES && NET_CORE && INET # for TUN
2689 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2695 Test the kernel's module loading mechanism: kmod. kmod implements
2696 support to load modules using the Linux kernel's usermode helper.
2697 This test provides a series of tests against kmod.
2699 Although technically you can either build test_kmod as a module or
2700 into the kernel we disallow building it into the kernel since
2701 it stress tests request_module() and this will very likely cause
2702 some issues by taking over precious threads available from other
2703 module load requests, ultimately this could be fatal.
2707 tools/testing/selftests/kmod/kmod.sh --help
2711 config TEST_DEBUG_VIRTUAL
2712 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2713 depends on DEBUG_VIRTUAL
2715 Test the kernel's ability to detect incorrect calls to
2716 virt_to_phys() done against the non-linear part of the
2717 kernel's virtual address map.
2721 config TEST_MEMCAT_P
2722 tristate "Test memcat_p() helper function"
2724 Test the memcat_p() helper for correctly merging two
2725 pointer arrays together.
2729 config TEST_LIVEPATCH
2730 tristate "Test livepatching"
2732 depends on DYNAMIC_DEBUG
2733 depends on LIVEPATCH
2736 Test kernel livepatching features for correctness. The tests will
2737 load test modules that will be livepatched in various scenarios.
2739 To run all the livepatching tests:
2741 make -C tools/testing/selftests TARGETS=livepatch run_tests
2743 Alternatively, individual tests may be invoked:
2745 tools/testing/selftests/livepatch/test-callbacks.sh
2746 tools/testing/selftests/livepatch/test-livepatch.sh
2747 tools/testing/selftests/livepatch/test-shadow-vars.sh
2752 tristate "Perform selftest on object aggreration manager"
2756 Enable this option to test object aggregation manager on boot
2760 tristate "Test heap/page initialization"
2762 Test if the kernel is zero-initializing heap and page allocations.
2763 This can be useful to test init_on_alloc and init_on_free features.
2768 tristate "Test HMM (Heterogeneous Memory Management)"
2769 depends on TRANSPARENT_HUGEPAGE
2770 depends on DEVICE_PRIVATE
2774 This is a pseudo device driver solely for testing HMM.
2775 Say M here if you want to build the HMM test module.
2776 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2780 config TEST_FREE_PAGES
2781 tristate "Test freeing pages"
2783 Test that a memory leak does not occur due to a race between
2784 freeing a block of pages and a speculative page reference.
2785 Loading this module is safe if your kernel has the bug fixed.
2786 If the bug is not fixed, it will leak gigabytes of memory and
2787 probably OOM your system.
2790 tristate "Test floating point operations in kernel space"
2791 depends on X86 && !KCOV_INSTRUMENT_ALL
2793 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2794 which will trigger a sequence of floating point operations. This is used
2795 for self-testing floating point control register setting in
2800 config TEST_CLOCKSOURCE_WATCHDOG
2801 tristate "Test clocksource watchdog in kernel space"
2802 depends on CLOCKSOURCE_WATCHDOG
2804 Enable this option to create a kernel module that will trigger
2805 a test of the clocksource watchdog. This module may be loaded
2806 via modprobe or insmod in which case it will run upon being
2807 loaded, or it may be built in, in which case it will run
2812 endif # RUNTIME_TESTING_MENU
2814 config ARCH_USE_MEMTEST
2817 An architecture should select this when it uses early_memtest()
2818 during boot process.
2822 depends on ARCH_USE_MEMTEST
2824 This option adds a kernel parameter 'memtest', which allows memtest
2825 to be set and executed.
2826 memtest=0, mean disabled; -- default
2827 memtest=1, mean do 1 test pattern;
2829 memtest=17, mean do 17 test patterns.
2830 If you are unsure how to answer this question, answer N.
2834 config HYPERV_TESTING
2835 bool "Microsoft Hyper-V driver testing"
2837 depends on HYPERV && DEBUG_FS
2839 Select this option to enable Hyper-V vmbus testing.
2841 endmenu # "Kernel Testing and Coverage"
2845 config RUST_DEBUG_ASSERTIONS
2846 bool "Debug assertions"
2849 Enables rustc's `-Cdebug-assertions` codegen option.
2851 This flag lets you turn `cfg(debug_assertions)` conditional
2852 compilation on or off. This can be used to enable extra debugging
2853 code in development but not in production. For example, it controls
2854 the behavior of the standard library's `debug_assert!` macro.
2856 Note that this will apply to all Rust code, including `core`.
2860 config RUST_OVERFLOW_CHECKS
2861 bool "Overflow checks"
2865 Enables rustc's `-Coverflow-checks` codegen option.
2867 This flag allows you to control the behavior of runtime integer
2868 overflow. When overflow-checks are enabled, a Rust panic will occur
2871 Note that this will apply to all Rust code, including `core`.
2875 config RUST_BUILD_ASSERT_ALLOW
2876 bool "Allow unoptimized build-time assertions"
2879 Controls how are `build_error!` and `build_assert!` handled during build.
2881 If calls to them exist in the binary, it may indicate a violated invariant
2882 or that the optimizer failed to verify the invariant during compilation.
2884 This should not happen, thus by default the build is aborted. However,
2885 as an escape hatch, you can choose Y here to ignore them during build
2886 and let the check be carried at runtime (with `panic!` being called if
2893 source "Documentation/Kconfig"
2895 endmenu # Kernel hacking
projects / linux-2.6-block.git / blob