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 DEBUG_INFO_BTF_MODULES
394 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
396 Generate compact split BTF type information for kernel modules.
398 config MODULE_ALLOW_BTF_MISMATCH
399 bool "Allow loading modules with non-matching BTF type info"
400 depends on DEBUG_INFO_BTF_MODULES
402 For modules whose split BTF does not match vmlinux, load without
403 BTF rather than refusing to load. The default behavior with
404 module BTF enabled is to reject modules with such mismatches;
405 this option will still load module BTF where possible but ignore
406 it when a mismatch is found.
409 bool "Provide GDB scripts for kernel debugging"
411 This creates the required links to GDB helper scripts in the
412 build directory. If you load vmlinux into gdb, the helper
413 scripts will be automatically imported by gdb as well, and
414 additional functions are available to analyze a Linux kernel
415 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
421 int "Warn for stack frames larger than"
424 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
425 default 2048 if PARISC
426 default 1536 if (!64BIT && XTENSA)
427 default 1280 if KASAN && !64BIT
428 default 1024 if !64BIT
429 default 2048 if 64BIT
431 Tell the compiler to warn at build time for stack frames larger than this.
432 Setting this too low will cause a lot of warnings.
433 Setting it to 0 disables the warning.
435 config STRIP_ASM_SYMS
436 bool "Strip assembler-generated symbols during link"
439 Strip internal assembler-generated symbols during a link (symbols
440 that look like '.Lxxx') so they don't pollute the output of
441 get_wchan() and suchlike.
444 bool "Generate readable assembler code"
445 depends on DEBUG_KERNEL
448 Disable some compiler optimizations that tend to generate human unreadable
449 assembler output. This may make the kernel slightly slower, but it helps
450 to keep kernel developers who have to stare a lot at assembler listings
453 config HEADERS_INSTALL
454 bool "Install uapi headers to usr/include"
457 This option will install uapi headers (headers exported to user-space)
458 into the usr/include directory for use during the kernel build.
459 This is unneeded for building the kernel itself, but needed for some
460 user-space program samples. It is also needed by some features such
461 as uapi header sanity checks.
463 config DEBUG_SECTION_MISMATCH
464 bool "Enable full Section mismatch analysis"
467 The section mismatch analysis checks if there are illegal
468 references from one section to another section.
469 During linktime or runtime, some sections are dropped;
470 any use of code/data previously in these sections would
471 most likely result in an oops.
472 In the code, functions and variables are annotated with
473 __init,, etc. (see the full list in include/linux/init.h),
474 which results in the code/data being placed in specific sections.
475 The section mismatch analysis is always performed after a full
476 kernel build, and enabling this option causes the following
477 additional step to occur:
478 - Add the option -fno-inline-functions-called-once to gcc commands.
479 When inlining a function annotated with __init in a non-init
480 function, we would lose the section information and thus
481 the analysis would not catch the illegal reference.
482 This option tells gcc to inline less (but it does result in
485 config SECTION_MISMATCH_WARN_ONLY
486 bool "Make section mismatch errors non-fatal"
489 If you say N here, the build process will fail if there are any
490 section mismatch, instead of just throwing warnings.
494 config DEBUG_FORCE_FUNCTION_ALIGN_64B
495 bool "Force all function address 64B aligned"
496 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC)
497 select FUNCTION_ALIGNMENT_64B
499 There are cases that a commit from one domain changes the function
500 address alignment of other domains, and cause magic performance
501 bump (regression or improvement). Enable this option will help to
502 verify if the bump is caused by function alignment changes, while
503 it will slightly increase the kernel size and affect icache usage.
505 It is mainly for debug and performance tuning use.
508 # Select this config option from the architecture Kconfig, if it
509 # is preferred to always offer frame pointers as a config
510 # option on the architecture (regardless of KERNEL_DEBUG):
512 config ARCH_WANT_FRAME_POINTERS
516 bool "Compile the kernel with frame pointers"
517 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
518 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
520 If you say Y here the resulting kernel image will be slightly
521 larger and slower, but it gives very useful debugging information
522 in case of kernel bugs. (precise oopses/stacktraces/warnings)
527 config STACK_VALIDATION
528 bool "Compile-time stack metadata validation"
529 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
533 Validate frame pointer rules at compile-time. This helps ensure that
534 runtime stack traces are more reliable.
536 For more information, see
537 tools/objtool/Documentation/objtool.txt.
539 config NOINSTR_VALIDATION
541 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
546 bool "Generate vmlinux.map file when linking"
549 Selecting this option will pass "-Map=vmlinux.map" to ld
550 when linking vmlinux. That file can be useful for verifying
551 and debugging magic section games, and for seeing which
552 pieces of code get eliminated with
553 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
555 config DEBUG_FORCE_WEAK_PER_CPU
556 bool "Force weak per-cpu definitions"
557 depends on DEBUG_KERNEL
559 s390 and alpha require percpu variables in modules to be
560 defined weak to work around addressing range issue which
561 puts the following two restrictions on percpu variable
564 1. percpu symbols must be unique whether static or not
565 2. percpu variables can't be defined inside a function
567 To ensure that generic code follows the above rules, this
568 option forces all percpu variables to be defined as weak.
570 endmenu # "Compiler options"
572 menu "Generic Kernel Debugging Instruments"
575 bool "Magic SysRq key"
578 If you say Y here, you will have some control over the system even
579 if the system crashes for example during kernel debugging (e.g., you
580 will be able to flush the buffer cache to disk, reboot the system
581 immediately or dump some status information). This is accomplished
582 by pressing various keys while holding SysRq (Alt+PrintScreen). It
583 also works on a serial console (on PC hardware at least), if you
584 send a BREAK and then within 5 seconds a command keypress. The
585 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
586 Don't say Y unless you really know what this hack does.
588 config MAGIC_SYSRQ_DEFAULT_ENABLE
589 hex "Enable magic SysRq key functions by default"
590 depends on MAGIC_SYSRQ
593 Specifies which SysRq key functions are enabled by default.
594 This may be set to 1 or 0 to enable or disable them all, or
595 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
597 config MAGIC_SYSRQ_SERIAL
598 bool "Enable magic SysRq key over serial"
599 depends on MAGIC_SYSRQ
602 Many embedded boards have a disconnected TTL level serial which can
603 generate some garbage that can lead to spurious false sysrq detects.
604 This option allows you to decide whether you want to enable the
607 config MAGIC_SYSRQ_SERIAL_SEQUENCE
608 string "Char sequence that enables magic SysRq over serial"
609 depends on MAGIC_SYSRQ_SERIAL
612 Specifies a sequence of characters that can follow BREAK to enable
613 SysRq on a serial console.
615 If unsure, leave an empty string and the option will not be enabled.
618 bool "Debug Filesystem"
620 debugfs is a virtual file system that kernel developers use to put
621 debugging files into. Enable this option to be able to read and
622 write to these files.
624 For detailed documentation on the debugfs API, see
625 Documentation/filesystems/.
630 prompt "Debugfs default access"
632 default DEBUG_FS_ALLOW_ALL
634 This selects the default access restrictions for debugfs.
635 It can be overridden with kernel command line option
636 debugfs=[on,no-mount,off]. The restrictions apply for API access
637 and filesystem registration.
639 config DEBUG_FS_ALLOW_ALL
642 No restrictions apply. Both API and filesystem registration
643 is on. This is the normal default operation.
645 config DEBUG_FS_DISALLOW_MOUNT
646 bool "Do not register debugfs as filesystem"
648 The API is open but filesystem is not loaded. Clients can still do
649 their work and read with debug tools that do not need
652 config DEBUG_FS_ALLOW_NONE
655 Access is off. Clients get -PERM when trying to create nodes in
656 debugfs tree and debugfs is not registered as a filesystem.
657 Client can then back-off or continue without debugfs access.
661 source "lib/Kconfig.kgdb"
662 source "lib/Kconfig.ubsan"
663 source "lib/Kconfig.kcsan"
667 menu "Networking Debugging"
669 source "net/Kconfig.debug"
671 endmenu # "Networking Debugging"
673 menu "Memory Debugging"
675 source "mm/Kconfig.debug"
678 bool "Debug object operations"
679 depends on DEBUG_KERNEL
681 If you say Y here, additional code will be inserted into the
682 kernel to track the life time of various objects and validate
683 the operations on those objects.
685 config DEBUG_OBJECTS_SELFTEST
686 bool "Debug objects selftest"
687 depends on DEBUG_OBJECTS
689 This enables the selftest of the object debug code.
691 config DEBUG_OBJECTS_FREE
692 bool "Debug objects in freed memory"
693 depends on DEBUG_OBJECTS
695 This enables checks whether a k/v free operation frees an area
696 which contains an object which has not been deactivated
697 properly. This can make kmalloc/kfree-intensive workloads
700 config DEBUG_OBJECTS_TIMERS
701 bool "Debug timer objects"
702 depends on DEBUG_OBJECTS
704 If you say Y here, additional code will be inserted into the
705 timer routines to track the life time of timer objects and
706 validate the timer operations.
708 config DEBUG_OBJECTS_WORK
709 bool "Debug work objects"
710 depends on DEBUG_OBJECTS
712 If you say Y here, additional code will be inserted into the
713 work queue routines to track the life time of work objects and
714 validate the work operations.
716 config DEBUG_OBJECTS_RCU_HEAD
717 bool "Debug RCU callbacks objects"
718 depends on DEBUG_OBJECTS
720 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
722 config DEBUG_OBJECTS_PERCPU_COUNTER
723 bool "Debug percpu counter objects"
724 depends on DEBUG_OBJECTS
726 If you say Y here, additional code will be inserted into the
727 percpu counter routines to track the life time of percpu counter
728 objects and validate the percpu counter operations.
730 config DEBUG_OBJECTS_ENABLE_DEFAULT
731 int "debug_objects bootup default value (0-1)"
734 depends on DEBUG_OBJECTS
736 Debug objects boot parameter default value
738 config SHRINKER_DEBUG
739 bool "Enable shrinker debugging support"
742 Say Y to enable the shrinker debugfs interface which provides
743 visibility into the kernel memory shrinkers subsystem.
744 Disable it to avoid an extra memory footprint.
746 config HAVE_DEBUG_KMEMLEAK
749 config DEBUG_KMEMLEAK
750 bool "Kernel memory leak detector"
751 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
753 select STACKTRACE if STACKTRACE_SUPPORT
757 select STACKDEPOT_ALWAYS_INIT if !DEBUG_KMEMLEAK_DEFAULT_OFF
759 Say Y here if you want to enable the memory leak
760 detector. The memory allocation/freeing is traced in a way
761 similar to the Boehm's conservative garbage collector, the
762 difference being that the orphan objects are not freed but
763 only shown in /sys/kernel/debug/kmemleak. Enabling this
764 feature will introduce an overhead to memory
765 allocations. See Documentation/dev-tools/kmemleak.rst for more
768 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
769 of finding leaks due to the slab objects poisoning.
771 In order to access the kmemleak file, debugfs needs to be
772 mounted (usually at /sys/kernel/debug).
774 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
775 int "Kmemleak memory pool size"
776 depends on DEBUG_KMEMLEAK
780 Kmemleak must track all the memory allocations to avoid
781 reporting false positives. Since memory may be allocated or
782 freed before kmemleak is fully initialised, use a static pool
783 of metadata objects to track such callbacks. After kmemleak is
784 fully initialised, this memory pool acts as an emergency one
785 if slab allocations fail.
787 config DEBUG_KMEMLEAK_TEST
788 tristate "Simple test for the kernel memory leak detector"
789 depends on DEBUG_KMEMLEAK && m
791 This option enables a module that explicitly leaks memory.
795 config DEBUG_KMEMLEAK_DEFAULT_OFF
796 bool "Default kmemleak to off"
797 depends on DEBUG_KMEMLEAK
799 Say Y here to disable kmemleak by default. It can then be enabled
800 on the command line via kmemleak=on.
802 config DEBUG_KMEMLEAK_AUTO_SCAN
803 bool "Enable kmemleak auto scan thread on boot up"
805 depends on DEBUG_KMEMLEAK
807 Depending on the cpu, kmemleak scan may be cpu intensive and can
808 stall user tasks at times. This option enables/disables automatic
809 kmemleak scan at boot up.
811 Say N here to disable kmemleak auto scan thread to stop automatic
812 scanning. Disabling this option disables automatic reporting of
817 config DEBUG_STACK_USAGE
818 bool "Stack utilization instrumentation"
819 depends on DEBUG_KERNEL && !IA64
821 Enables the display of the minimum amount of free stack which each
822 task has ever had available in the sysrq-T and sysrq-P debug output.
824 This option will slow down process creation somewhat.
826 config SCHED_STACK_END_CHECK
827 bool "Detect stack corruption on calls to schedule()"
828 depends on DEBUG_KERNEL
831 This option checks for a stack overrun on calls to schedule().
832 If the stack end location is found to be over written always panic as
833 the content of the corrupted region can no longer be trusted.
834 This is to ensure no erroneous behaviour occurs which could result in
835 data corruption or a sporadic crash at a later stage once the region
836 is examined. The runtime overhead introduced is minimal.
838 config ARCH_HAS_DEBUG_VM_PGTABLE
841 An architecture should select this when it can successfully
842 build and run DEBUG_VM_PGTABLE.
844 config DEBUG_VM_IRQSOFF
845 def_bool DEBUG_VM && !PREEMPT_RT
849 depends on DEBUG_KERNEL
851 Enable this to turn on extended checks in the virtual-memory system
852 that may impact performance.
856 config DEBUG_VM_MAPLE_TREE
857 bool "Debug VM maple trees"
859 select DEBUG_MAPLE_TREE
861 Enable VM maple tree debugging information and extra validations.
866 bool "Debug VM red-black trees"
869 Enable VM red-black tree debugging information and extra validations.
873 config DEBUG_VM_PGFLAGS
874 bool "Debug page-flags operations"
877 Enables extra validation on page flags operations.
881 config DEBUG_VM_PGTABLE
882 bool "Debug arch page table for semantics compliance"
884 depends on ARCH_HAS_DEBUG_VM_PGTABLE
885 default y if DEBUG_VM
887 This option provides a debug method which can be used to test
888 architecture page table helper functions on various platforms in
889 verifying if they comply with expected generic MM semantics. This
890 will help architecture code in making sure that any changes or
891 new additions of these helpers still conform to expected
892 semantics of the generic MM. Platforms will have to opt in for
893 this through ARCH_HAS_DEBUG_VM_PGTABLE.
897 config ARCH_HAS_DEBUG_VIRTUAL
901 bool "Debug VM translations"
902 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
904 Enable some costly sanity checks in virtual to page code. This can
905 catch mistakes with virt_to_page() and friends.
909 config DEBUG_NOMMU_REGIONS
910 bool "Debug the global anon/private NOMMU mapping region tree"
911 depends on DEBUG_KERNEL && !MMU
913 This option causes the global tree of anonymous and private mapping
914 regions to be regularly checked for invalid topology.
916 config DEBUG_MEMORY_INIT
917 bool "Debug memory initialisation" if EXPERT
920 Enable this for additional checks during memory initialisation.
921 The sanity checks verify aspects of the VM such as the memory model
922 and other information provided by the architecture. Verbose
923 information will be printed at KERN_DEBUG loglevel depending
924 on the mminit_loglevel= command-line option.
928 config MEMORY_NOTIFIER_ERROR_INJECT
929 tristate "Memory hotplug notifier error injection module"
930 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
932 This option provides the ability to inject artificial errors to
933 memory hotplug notifier chain callbacks. It is controlled through
934 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
936 If the notifier call chain should be failed with some events
937 notified, write the error code to "actions/<notifier event>/error".
939 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
941 # cd /sys/kernel/debug/notifier-error-inject/memory
942 # echo -12 > actions/MEM_GOING_OFFLINE/error
943 # echo offline > /sys/devices/system/memory/memoryXXX/state
944 bash: echo: write error: Cannot allocate memory
946 To compile this code as a module, choose M here: the module will
947 be called memory-notifier-error-inject.
951 config DEBUG_PER_CPU_MAPS
952 bool "Debug access to per_cpu maps"
953 depends on DEBUG_KERNEL
956 Say Y to verify that the per_cpu map being accessed has
957 been set up. This adds a fair amount of code to kernel memory
958 and decreases performance.
962 config DEBUG_KMAP_LOCAL
963 bool "Debug kmap_local temporary mappings"
964 depends on DEBUG_KERNEL && KMAP_LOCAL
966 This option enables additional error checking for the kmap_local
967 infrastructure. Disable for production use.
969 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
972 config DEBUG_KMAP_LOCAL_FORCE_MAP
973 bool "Enforce kmap_local temporary mappings"
974 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
976 select DEBUG_KMAP_LOCAL
978 This option enforces temporary mappings through the kmap_local
979 mechanism for non-highmem pages and on non-highmem systems.
980 Disable this for production systems!
983 bool "Highmem debugging"
984 depends on DEBUG_KERNEL && HIGHMEM
985 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
986 select DEBUG_KMAP_LOCAL
988 This option enables additional error checking for high memory
989 systems. Disable for production systems.
991 config HAVE_DEBUG_STACKOVERFLOW
994 config DEBUG_STACKOVERFLOW
995 bool "Check for stack overflows"
996 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
998 Say Y here if you want to check for overflows of kernel, IRQ
999 and exception stacks (if your architecture uses them). This
1000 option will show detailed messages if free stack space drops
1001 below a certain limit.
1003 These kinds of bugs usually occur when call-chains in the
1004 kernel get too deep, especially when interrupts are
1007 Use this in cases where you see apparently random memory
1008 corruption, especially if it appears in 'struct thread_info'
1010 If in doubt, say "N".
1012 source "lib/Kconfig.kasan"
1013 source "lib/Kconfig.kfence"
1014 source "lib/Kconfig.kmsan"
1016 endmenu # "Memory Debugging"
1019 bool "Debug shared IRQ handlers"
1020 depends on DEBUG_KERNEL
1022 Enable this to generate a spurious interrupt just before a shared
1023 interrupt handler is deregistered (generating one when registering
1024 is currently disabled). Drivers need to handle this correctly. Some
1025 don't and need to be caught.
1027 menu "Debug Oops, Lockups and Hangs"
1029 config PANIC_ON_OOPS
1030 bool "Panic on Oops"
1032 Say Y here to enable the kernel to panic when it oopses. This
1033 has the same effect as setting oops=panic on the kernel command
1036 This feature is useful to ensure that the kernel does not do
1037 anything erroneous after an oops which could result in data
1038 corruption or other issues.
1042 config PANIC_ON_OOPS_VALUE
1045 default 0 if !PANIC_ON_OOPS
1046 default 1 if PANIC_ON_OOPS
1048 config PANIC_TIMEOUT
1052 Set the timeout value (in seconds) until a reboot occurs when
1053 the kernel panics. If n = 0, then we wait forever. A timeout
1054 value n > 0 will wait n seconds before rebooting, while a timeout
1055 value n < 0 will reboot immediately.
1057 config LOCKUP_DETECTOR
1060 config SOFTLOCKUP_DETECTOR
1061 bool "Detect Soft Lockups"
1062 depends on DEBUG_KERNEL && !S390
1063 select LOCKUP_DETECTOR
1065 Say Y here to enable the kernel to act as a watchdog to detect
1068 Softlockups are bugs that cause the kernel to loop in kernel
1069 mode for more than 20 seconds, without giving other tasks a
1070 chance to run. The current stack trace is displayed upon
1071 detection and the system will stay locked up.
1073 config BOOTPARAM_SOFTLOCKUP_PANIC
1074 bool "Panic (Reboot) On Soft Lockups"
1075 depends on SOFTLOCKUP_DETECTOR
1077 Say Y here to enable the kernel to panic on "soft lockups",
1078 which are bugs that cause the kernel to loop in kernel
1079 mode for more than 20 seconds (configurable using the watchdog_thresh
1080 sysctl), without giving other tasks a chance to run.
1082 The panic can be used in combination with panic_timeout,
1083 to cause the system to reboot automatically after a
1084 lockup has been detected. This feature is useful for
1085 high-availability systems that have uptime guarantees and
1086 where a lockup must be resolved ASAP.
1090 config HARDLOCKUP_DETECTOR_PERF
1092 select SOFTLOCKUP_DETECTOR
1095 # Enables a timestamp based low pass filter to compensate for perf based
1096 # hard lockup detection which runs too fast due to turbo modes.
1098 config HARDLOCKUP_CHECK_TIMESTAMP
1102 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1103 # lockup detector rather than the perf based detector.
1105 config HARDLOCKUP_DETECTOR
1106 bool "Detect Hard Lockups"
1107 depends on DEBUG_KERNEL && !S390
1108 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1109 select LOCKUP_DETECTOR
1110 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1112 Say Y here to enable the kernel to act as a watchdog to detect
1115 Hardlockups are bugs that cause the CPU to loop in kernel mode
1116 for more than 10 seconds, without letting other interrupts have a
1117 chance to run. The current stack trace is displayed upon detection
1118 and the system will stay locked up.
1120 config BOOTPARAM_HARDLOCKUP_PANIC
1121 bool "Panic (Reboot) On Hard Lockups"
1122 depends on HARDLOCKUP_DETECTOR
1124 Say Y here to enable the kernel to panic on "hard lockups",
1125 which are bugs that cause the kernel to loop in kernel
1126 mode with interrupts disabled for more than 10 seconds (configurable
1127 using the watchdog_thresh sysctl).
1131 config DETECT_HUNG_TASK
1132 bool "Detect Hung Tasks"
1133 depends on DEBUG_KERNEL
1134 default SOFTLOCKUP_DETECTOR
1136 Say Y here to enable the kernel to detect "hung tasks",
1137 which are bugs that cause the task to be stuck in
1138 uninterruptible "D" state indefinitely.
1140 When a hung task is detected, the kernel will print the
1141 current stack trace (which you should report), but the
1142 task will stay in uninterruptible state. If lockdep is
1143 enabled then all held locks will also be reported. This
1144 feature has negligible overhead.
1146 config DEFAULT_HUNG_TASK_TIMEOUT
1147 int "Default timeout for hung task detection (in seconds)"
1148 depends on DETECT_HUNG_TASK
1151 This option controls the default timeout (in seconds) used
1152 to determine when a task has become non-responsive and should
1155 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1156 sysctl or by writing a value to
1157 /proc/sys/kernel/hung_task_timeout_secs.
1159 A timeout of 0 disables the check. The default is two minutes.
1160 Keeping the default should be fine in most cases.
1162 config BOOTPARAM_HUNG_TASK_PANIC
1163 bool "Panic (Reboot) On Hung Tasks"
1164 depends on DETECT_HUNG_TASK
1166 Say Y here to enable the kernel to panic on "hung tasks",
1167 which are bugs that cause the kernel to leave a task stuck
1168 in uninterruptible "D" state.
1170 The panic can be used in combination with panic_timeout,
1171 to cause the system to reboot automatically after a
1172 hung task has been detected. This feature is useful for
1173 high-availability systems that have uptime guarantees and
1174 where a hung tasks must be resolved ASAP.
1179 bool "Detect Workqueue Stalls"
1180 depends on DEBUG_KERNEL
1182 Say Y here to enable stall detection on workqueues. If a
1183 worker pool doesn't make forward progress on a pending work
1184 item for over a given amount of time, 30s by default, a
1185 warning message is printed along with dump of workqueue
1186 state. This can be configured through kernel parameter
1187 "workqueue.watchdog_thresh" and its sysfs counterpart.
1190 tristate "Test module to generate lockups"
1193 This builds the "test_lockup" module that helps to make sure
1194 that watchdogs and lockup detectors are working properly.
1196 Depending on module parameters it could emulate soft or hard
1197 lockup, "hung task", or locking arbitrary lock for a long time.
1198 Also it could generate series of lockups with cooling-down periods.
1202 endmenu # "Debug lockups and hangs"
1204 menu "Scheduler Debugging"
1207 bool "Collect scheduler debugging info"
1208 depends on DEBUG_KERNEL && PROC_FS
1211 If you say Y here, the /sys/kernel/debug/sched file will be provided
1212 that can help debug the scheduler. The runtime overhead of this
1220 bool "Collect scheduler statistics"
1221 depends on DEBUG_KERNEL && PROC_FS
1224 If you say Y here, additional code will be inserted into the
1225 scheduler and related routines to collect statistics about
1226 scheduler behavior and provide them in /proc/schedstat. These
1227 stats may be useful for both tuning and debugging the scheduler
1228 If you aren't debugging the scheduler or trying to tune a specific
1229 application, you can say N to avoid the very slight overhead
1234 config DEBUG_TIMEKEEPING
1235 bool "Enable extra timekeeping sanity checking"
1237 This option will enable additional timekeeping sanity checks
1238 which may be helpful when diagnosing issues where timekeeping
1239 problems are suspected.
1241 This may include checks in the timekeeping hotpaths, so this
1242 option may have a (very small) performance impact to some
1247 config DEBUG_PREEMPT
1248 bool "Debug preemptible kernel"
1249 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1252 If you say Y here then the kernel will use a debug variant of the
1253 commonly used smp_processor_id() function and will print warnings
1254 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1255 will detect preemption count underflows.
1257 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1259 config LOCK_DEBUGGING_SUPPORT
1261 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1264 config PROVE_LOCKING
1265 bool "Lock debugging: prove locking correctness"
1266 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1268 select DEBUG_SPINLOCK
1269 select DEBUG_MUTEXES if !PREEMPT_RT
1270 select DEBUG_RT_MUTEXES if RT_MUTEXES
1272 select DEBUG_WW_MUTEX_SLOWPATH
1273 select DEBUG_LOCK_ALLOC
1274 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1275 select TRACE_IRQFLAGS
1278 This feature enables the kernel to prove that all locking
1279 that occurs in the kernel runtime is mathematically
1280 correct: that under no circumstance could an arbitrary (and
1281 not yet triggered) combination of observed locking
1282 sequences (on an arbitrary number of CPUs, running an
1283 arbitrary number of tasks and interrupt contexts) cause a
1286 In short, this feature enables the kernel to report locking
1287 related deadlocks before they actually occur.
1289 The proof does not depend on how hard and complex a
1290 deadlock scenario would be to trigger: how many
1291 participant CPUs, tasks and irq-contexts would be needed
1292 for it to trigger. The proof also does not depend on
1293 timing: if a race and a resulting deadlock is possible
1294 theoretically (no matter how unlikely the race scenario
1295 is), it will be proven so and will immediately be
1296 reported by the kernel (once the event is observed that
1297 makes the deadlock theoretically possible).
1299 If a deadlock is impossible (i.e. the locking rules, as
1300 observed by the kernel, are mathematically correct), the
1301 kernel reports nothing.
1303 NOTE: this feature can also be enabled for rwlocks, mutexes
1304 and rwsems - in which case all dependencies between these
1305 different locking variants are observed and mapped too, and
1306 the proof of observed correctness is also maintained for an
1307 arbitrary combination of these separate locking variants.
1309 For more details, see Documentation/locking/lockdep-design.rst.
1311 config PROVE_RAW_LOCK_NESTING
1312 bool "Enable raw_spinlock - spinlock nesting checks"
1313 depends on PROVE_LOCKING
1316 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1317 that the lock nesting rules for PREEMPT_RT enabled kernels are
1320 NOTE: There are known nesting problems. So if you enable this
1321 option expect lockdep splats until these problems have been fully
1322 addressed which is work in progress. This config switch allows to
1323 identify and analyze these problems. It will be removed and the
1324 check permanently enabled once the main issues have been fixed.
1326 If unsure, select N.
1329 bool "Lock usage statistics"
1330 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1332 select DEBUG_SPINLOCK
1333 select DEBUG_MUTEXES if !PREEMPT_RT
1334 select DEBUG_RT_MUTEXES if RT_MUTEXES
1335 select DEBUG_LOCK_ALLOC
1338 This feature enables tracking lock contention points
1340 For more details, see Documentation/locking/lockstat.rst
1342 This also enables lock events required by "perf lock",
1344 If you want to use "perf lock", you also need to turn on
1345 CONFIG_EVENT_TRACING.
1347 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1348 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1350 config DEBUG_RT_MUTEXES
1351 bool "RT Mutex debugging, deadlock detection"
1352 depends on DEBUG_KERNEL && RT_MUTEXES
1354 This allows rt mutex semantics violations and rt mutex related
1355 deadlocks (lockups) to be detected and reported automatically.
1357 config DEBUG_SPINLOCK
1358 bool "Spinlock and rw-lock debugging: basic checks"
1359 depends on DEBUG_KERNEL
1360 select UNINLINE_SPIN_UNLOCK
1362 Say Y here and build SMP to catch missing spinlock initialization
1363 and certain other kinds of spinlock errors commonly made. This is
1364 best used in conjunction with the NMI watchdog so that spinlock
1365 deadlocks are also debuggable.
1367 config DEBUG_MUTEXES
1368 bool "Mutex debugging: basic checks"
1369 depends on DEBUG_KERNEL && !PREEMPT_RT
1371 This feature allows mutex semantics violations to be detected and
1374 config DEBUG_WW_MUTEX_SLOWPATH
1375 bool "Wait/wound mutex debugging: Slowpath testing"
1376 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1377 select DEBUG_LOCK_ALLOC
1378 select DEBUG_SPINLOCK
1379 select DEBUG_MUTEXES if !PREEMPT_RT
1380 select DEBUG_RT_MUTEXES if PREEMPT_RT
1382 This feature enables slowpath testing for w/w mutex users by
1383 injecting additional -EDEADLK wound/backoff cases. Together with
1384 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1385 will test all possible w/w mutex interface abuse with the
1386 exception of simply not acquiring all the required locks.
1387 Note that this feature can introduce significant overhead, so
1388 it really should not be enabled in a production or distro kernel,
1389 even a debug kernel. If you are a driver writer, enable it. If
1390 you are a distro, do not.
1393 bool "RW Semaphore debugging: basic checks"
1394 depends on DEBUG_KERNEL
1396 This debugging feature allows mismatched rw semaphore locks
1397 and unlocks to be detected and reported.
1399 config DEBUG_LOCK_ALLOC
1400 bool "Lock debugging: detect incorrect freeing of live locks"
1401 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1402 select DEBUG_SPINLOCK
1403 select DEBUG_MUTEXES if !PREEMPT_RT
1404 select DEBUG_RT_MUTEXES if RT_MUTEXES
1407 This feature will check whether any held lock (spinlock, rwlock,
1408 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1409 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1410 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1411 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1412 held during task exit.
1416 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1421 config LOCKDEP_SMALL
1425 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1426 depends on LOCKDEP && !LOCKDEP_SMALL
1430 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1432 config LOCKDEP_CHAINS_BITS
1433 int "Bitsize for MAX_LOCKDEP_CHAINS"
1434 depends on LOCKDEP && !LOCKDEP_SMALL
1438 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1440 config LOCKDEP_STACK_TRACE_BITS
1441 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1442 depends on LOCKDEP && !LOCKDEP_SMALL
1446 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1448 config LOCKDEP_STACK_TRACE_HASH_BITS
1449 int "Bitsize for STACK_TRACE_HASH_SIZE"
1450 depends on LOCKDEP && !LOCKDEP_SMALL
1454 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1456 config LOCKDEP_CIRCULAR_QUEUE_BITS
1457 int "Bitsize for elements in circular_queue struct"
1462 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1464 config DEBUG_LOCKDEP
1465 bool "Lock dependency engine debugging"
1466 depends on DEBUG_KERNEL && LOCKDEP
1467 select DEBUG_IRQFLAGS
1469 If you say Y here, the lock dependency engine will do
1470 additional runtime checks to debug itself, at the price
1471 of more runtime overhead.
1473 config DEBUG_ATOMIC_SLEEP
1474 bool "Sleep inside atomic section checking"
1475 select PREEMPT_COUNT
1476 depends on DEBUG_KERNEL
1477 depends on !ARCH_NO_PREEMPT
1479 If you say Y here, various routines which may sleep will become very
1480 noisy if they are called inside atomic sections: when a spinlock is
1481 held, inside an rcu read side critical section, inside preempt disabled
1482 sections, inside an interrupt, etc...
1484 config DEBUG_LOCKING_API_SELFTESTS
1485 bool "Locking API boot-time self-tests"
1486 depends on DEBUG_KERNEL
1488 Say Y here if you want the kernel to run a short self-test during
1489 bootup. The self-test checks whether common types of locking bugs
1490 are detected by debugging mechanisms or not. (if you disable
1491 lock debugging then those bugs won't be detected of course.)
1492 The following locking APIs are covered: spinlocks, rwlocks,
1495 config LOCK_TORTURE_TEST
1496 tristate "torture tests for locking"
1497 depends on DEBUG_KERNEL
1500 This option provides a kernel module that runs torture tests
1501 on kernel locking primitives. The kernel module may be built
1502 after the fact on the running kernel to be tested, if desired.
1504 Say Y here if you want kernel locking-primitive torture tests
1505 to be built into the kernel.
1506 Say M if you want these torture tests to build as a module.
1507 Say N if you are unsure.
1509 config WW_MUTEX_SELFTEST
1510 tristate "Wait/wound mutex selftests"
1512 This option provides a kernel module that runs tests on the
1513 on the struct ww_mutex locking API.
1515 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1516 with this test harness.
1518 Say M if you want these self tests to build as a module.
1519 Say N if you are unsure.
1521 config SCF_TORTURE_TEST
1522 tristate "torture tests for smp_call_function*()"
1523 depends on DEBUG_KERNEL
1526 This option provides a kernel module that runs torture tests
1527 on the smp_call_function() family of primitives. The kernel
1528 module may be built after the fact on the running kernel to
1529 be tested, if desired.
1531 config CSD_LOCK_WAIT_DEBUG
1532 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1533 depends on DEBUG_KERNEL
1537 This option enables debug prints when CPUs are slow to respond
1538 to the smp_call_function*() IPI wrappers. These debug prints
1539 include the IPI handler function currently executing (if any)
1540 and relevant stack traces.
1542 endmenu # lock debugging
1544 config TRACE_IRQFLAGS
1545 depends on TRACE_IRQFLAGS_SUPPORT
1548 Enables hooks to interrupt enabling and disabling for
1549 either tracing or lock debugging.
1551 config TRACE_IRQFLAGS_NMI
1553 depends on TRACE_IRQFLAGS
1554 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1556 config DEBUG_IRQFLAGS
1557 bool "Debug IRQ flag manipulation"
1559 Enables checks for potentially unsafe enabling or disabling of
1560 interrupts, such as calling raw_local_irq_restore() when interrupts
1564 bool "Stack backtrace support"
1565 depends on STACKTRACE_SUPPORT
1567 This option causes the kernel to create a /proc/pid/stack for
1568 every process, showing its current stack trace.
1569 It is also used by various kernel debugging features that require
1570 stack trace generation.
1572 config WARN_ALL_UNSEEDED_RANDOM
1573 bool "Warn for all uses of unseeded randomness"
1576 Some parts of the kernel contain bugs relating to their use of
1577 cryptographically secure random numbers before it's actually possible
1578 to generate those numbers securely. This setting ensures that these
1579 flaws don't go unnoticed, by enabling a message, should this ever
1580 occur. This will allow people with obscure setups to know when things
1581 are going wrong, so that they might contact developers about fixing
1584 Unfortunately, on some models of some architectures getting
1585 a fully seeded CRNG is extremely difficult, and so this can
1586 result in dmesg getting spammed for a surprisingly long
1587 time. This is really bad from a security perspective, and
1588 so architecture maintainers really need to do what they can
1589 to get the CRNG seeded sooner after the system is booted.
1590 However, since users cannot do anything actionable to
1591 address this, by default this option is disabled.
1593 Say Y here if you want to receive warnings for all uses of
1594 unseeded randomness. This will be of use primarily for
1595 those developers interested in improving the security of
1596 Linux kernels running on their architecture (or
1599 config DEBUG_KOBJECT
1600 bool "kobject debugging"
1601 depends on DEBUG_KERNEL
1603 If you say Y here, some extra kobject debugging messages will be sent
1606 config DEBUG_KOBJECT_RELEASE
1607 bool "kobject release debugging"
1608 depends on DEBUG_OBJECTS_TIMERS
1610 kobjects are reference counted objects. This means that their
1611 last reference count put is not predictable, and the kobject can
1612 live on past the point at which a driver decides to drop its
1613 initial reference to the kobject gained on allocation. An
1614 example of this would be a struct device which has just been
1617 However, some buggy drivers assume that after such an operation,
1618 the memory backing the kobject can be immediately freed. This
1619 goes completely against the principles of a refcounted object.
1621 If you say Y here, the kernel will delay the release of kobjects
1622 on the last reference count to improve the visibility of this
1623 kind of kobject release bug.
1625 config HAVE_DEBUG_BUGVERBOSE
1628 menu "Debug kernel data structures"
1631 bool "Debug linked list manipulation"
1632 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1634 Enable this to turn on extended checks in the linked-list
1640 bool "Debug priority linked list manipulation"
1641 depends on DEBUG_KERNEL
1643 Enable this to turn on extended checks in the priority-ordered
1644 linked-list (plist) walking routines. This checks the entire
1645 list multiple times during each manipulation.
1650 bool "Debug SG table operations"
1651 depends on DEBUG_KERNEL
1653 Enable this to turn on checks on scatter-gather tables. This can
1654 help find problems with drivers that do not properly initialize
1659 config DEBUG_NOTIFIERS
1660 bool "Debug notifier call chains"
1661 depends on DEBUG_KERNEL
1663 Enable this to turn on sanity checking for notifier call chains.
1664 This is most useful for kernel developers to make sure that
1665 modules properly unregister themselves from notifier chains.
1666 This is a relatively cheap check but if you care about maximum
1669 config BUG_ON_DATA_CORRUPTION
1670 bool "Trigger a BUG when data corruption is detected"
1673 Select this option if the kernel should BUG when it encounters
1674 data corruption in kernel memory structures when they get checked
1679 config DEBUG_MAPLE_TREE
1680 bool "Debug maple trees"
1681 depends on DEBUG_KERNEL
1683 Enable maple tree debugging information and extra validations.
1689 config DEBUG_CREDENTIALS
1690 bool "Debug credential management"
1691 depends on DEBUG_KERNEL
1693 Enable this to turn on some debug checking for credential
1694 management. The additional code keeps track of the number of
1695 pointers from task_structs to any given cred struct, and checks to
1696 see that this number never exceeds the usage count of the cred
1699 Furthermore, if SELinux is enabled, this also checks that the
1700 security pointer in the cred struct is never seen to be invalid.
1704 source "kernel/rcu/Kconfig.debug"
1706 config DEBUG_WQ_FORCE_RR_CPU
1707 bool "Force round-robin CPU selection for unbound work items"
1708 depends on DEBUG_KERNEL
1711 Workqueue used to implicitly guarantee that work items queued
1712 without explicit CPU specified are put on the local CPU. This
1713 guarantee is no longer true and while local CPU is still
1714 preferred work items may be put on foreign CPUs. Kernel
1715 parameter "workqueue.debug_force_rr_cpu" is added to force
1716 round-robin CPU selection to flush out usages which depend on the
1717 now broken guarantee. This config option enables the debug
1718 feature by default. When enabled, memory and cache locality will
1721 config CPU_HOTPLUG_STATE_CONTROL
1722 bool "Enable CPU hotplug state control"
1723 depends on DEBUG_KERNEL
1724 depends on HOTPLUG_CPU
1727 Allows to write steps between "offline" and "online" to the CPUs
1728 sysfs target file so states can be stepped granular. This is a debug
1729 option for now as the hotplug machinery cannot be stopped and
1730 restarted at arbitrary points yet.
1732 Say N if your are unsure.
1735 bool "Latency measuring infrastructure"
1736 depends on DEBUG_KERNEL
1737 depends on STACKTRACE_SUPPORT
1739 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1745 Enable this option if you want to use the LatencyTOP tool
1746 to find out which userspace is blocking on what kernel operations.
1748 config DEBUG_CGROUP_REF
1749 bool "Disable inlining of cgroup css reference count functions"
1750 depends on DEBUG_KERNEL
1755 Force cgroup css reference count functions to not be inlined so
1756 that they can be kprobed for debugging.
1758 source "kernel/trace/Kconfig"
1760 config PROVIDE_OHCI1394_DMA_INIT
1761 bool "Remote debugging over FireWire early on boot"
1762 depends on PCI && X86
1764 If you want to debug problems which hang or crash the kernel early
1765 on boot and the crashing machine has a FireWire port, you can use
1766 this feature to remotely access the memory of the crashed machine
1767 over FireWire. This employs remote DMA as part of the OHCI1394
1768 specification which is now the standard for FireWire controllers.
1770 With remote DMA, you can monitor the printk buffer remotely using
1771 firescope and access all memory below 4GB using fireproxy from gdb.
1772 Even controlling a kernel debugger is possible using remote DMA.
1776 If ohci1394_dma=early is used as boot parameter, it will initialize
1777 all OHCI1394 controllers which are found in the PCI config space.
1779 As all changes to the FireWire bus such as enabling and disabling
1780 devices cause a bus reset and thereby disable remote DMA for all
1781 devices, be sure to have the cable plugged and FireWire enabled on
1782 the debugging host before booting the debug target for debugging.
1784 This code (~1k) is freed after boot. By then, the firewire stack
1785 in charge of the OHCI-1394 controllers should be used instead.
1787 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1789 source "samples/Kconfig"
1791 config ARCH_HAS_DEVMEM_IS_ALLOWED
1794 config STRICT_DEVMEM
1795 bool "Filter access to /dev/mem"
1796 depends on MMU && DEVMEM
1797 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1798 default y if PPC || X86 || ARM64
1800 If this option is disabled, you allow userspace (root) access to all
1801 of memory, including kernel and userspace memory. Accidental
1802 access to this is obviously disastrous, but specific access can
1803 be used by people debugging the kernel. Note that with PAT support
1804 enabled, even in this case there are restrictions on /dev/mem
1805 use due to the cache aliasing requirements.
1807 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1808 file only allows userspace access to PCI space and the BIOS code and
1809 data regions. This is sufficient for dosemu and X and all common
1814 config IO_STRICT_DEVMEM
1815 bool "Filter I/O access to /dev/mem"
1816 depends on STRICT_DEVMEM
1818 If this option is disabled, you allow userspace (root) access to all
1819 io-memory regardless of whether a driver is actively using that
1820 range. Accidental access to this is obviously disastrous, but
1821 specific access can be used by people debugging kernel drivers.
1823 If this option is switched on, the /dev/mem file only allows
1824 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1825 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1826 if the driver using a given range cannot be disabled.
1830 menu "$(SRCARCH) Debugging"
1832 source "arch/$(SRCARCH)/Kconfig.debug"
1836 menu "Kernel Testing and Coverage"
1838 source "lib/kunit/Kconfig"
1840 config NOTIFIER_ERROR_INJECTION
1841 tristate "Notifier error injection"
1842 depends on DEBUG_KERNEL
1845 This option provides the ability to inject artificial errors to
1846 specified notifier chain callbacks. It is useful to test the error
1847 handling of notifier call chain failures.
1851 config PM_NOTIFIER_ERROR_INJECT
1852 tristate "PM notifier error injection module"
1853 depends on PM && NOTIFIER_ERROR_INJECTION
1854 default m if PM_DEBUG
1856 This option provides the ability to inject artificial errors to
1857 PM notifier chain callbacks. It is controlled through debugfs
1858 interface /sys/kernel/debug/notifier-error-inject/pm
1860 If the notifier call chain should be failed with some events
1861 notified, write the error code to "actions/<notifier event>/error".
1863 Example: Inject PM suspend error (-12 = -ENOMEM)
1865 # cd /sys/kernel/debug/notifier-error-inject/pm/
1866 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1867 # echo mem > /sys/power/state
1868 bash: echo: write error: Cannot allocate memory
1870 To compile this code as a module, choose M here: the module will
1871 be called pm-notifier-error-inject.
1875 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1876 tristate "OF reconfig notifier error injection module"
1877 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1879 This option provides the ability to inject artificial errors to
1880 OF reconfig notifier chain callbacks. It is controlled
1881 through debugfs interface under
1882 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1884 If the notifier call chain should be failed with some events
1885 notified, write the error code to "actions/<notifier event>/error".
1887 To compile this code as a module, choose M here: the module will
1888 be called of-reconfig-notifier-error-inject.
1892 config NETDEV_NOTIFIER_ERROR_INJECT
1893 tristate "Netdev notifier error injection module"
1894 depends on NET && NOTIFIER_ERROR_INJECTION
1896 This option provides the ability to inject artificial errors to
1897 netdevice notifier chain callbacks. It is controlled through debugfs
1898 interface /sys/kernel/debug/notifier-error-inject/netdev
1900 If the notifier call chain should be failed with some events
1901 notified, write the error code to "actions/<notifier event>/error".
1903 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1905 # cd /sys/kernel/debug/notifier-error-inject/netdev
1906 # echo -22 > actions/NETDEV_CHANGEMTU/error
1907 # ip link set eth0 mtu 1024
1908 RTNETLINK answers: Invalid argument
1910 To compile this code as a module, choose M here: the module will
1911 be called netdev-notifier-error-inject.
1915 config FUNCTION_ERROR_INJECTION
1916 bool "Fault-injections of functions"
1917 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1919 Add fault injections into various functions that are annotated with
1920 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
1921 value of these functions. This is useful to test error paths of code.
1925 config FAULT_INJECTION
1926 bool "Fault-injection framework"
1927 depends on DEBUG_KERNEL
1929 Provide fault-injection framework.
1930 For more details, see Documentation/fault-injection/.
1933 bool "Fault-injection capability for kmalloc"
1934 depends on FAULT_INJECTION
1935 depends on SLAB || SLUB
1937 Provide fault-injection capability for kmalloc.
1939 config FAIL_PAGE_ALLOC
1940 bool "Fault-injection capability for alloc_pages()"
1941 depends on FAULT_INJECTION
1943 Provide fault-injection capability for alloc_pages().
1945 config FAULT_INJECTION_USERCOPY
1946 bool "Fault injection capability for usercopy functions"
1947 depends on FAULT_INJECTION
1949 Provides fault-injection capability to inject failures
1950 in usercopy functions (copy_from_user(), get_user(), ...).
1952 config FAIL_MAKE_REQUEST
1953 bool "Fault-injection capability for disk IO"
1954 depends on FAULT_INJECTION && BLOCK
1956 Provide fault-injection capability for disk IO.
1958 config FAIL_IO_TIMEOUT
1959 bool "Fault-injection capability for faking disk interrupts"
1960 depends on FAULT_INJECTION && BLOCK
1962 Provide fault-injection capability on end IO handling. This
1963 will make the block layer "forget" an interrupt as configured,
1964 thus exercising the error handling.
1966 Only works with drivers that use the generic timeout handling,
1967 for others it won't do anything.
1970 bool "Fault-injection capability for futexes"
1972 depends on FAULT_INJECTION && FUTEX
1974 Provide fault-injection capability for futexes.
1976 config FAULT_INJECTION_DEBUG_FS
1977 bool "Debugfs entries for fault-injection capabilities"
1978 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1980 Enable configuration of fault-injection capabilities via debugfs.
1982 config FAIL_FUNCTION
1983 bool "Fault-injection capability for functions"
1984 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1986 Provide function-based fault-injection capability.
1987 This will allow you to override a specific function with a return
1988 with given return value. As a result, function caller will see
1989 an error value and have to handle it. This is useful to test the
1990 error handling in various subsystems.
1992 config FAIL_MMC_REQUEST
1993 bool "Fault-injection capability for MMC IO"
1994 depends on FAULT_INJECTION_DEBUG_FS && MMC
1996 Provide fault-injection capability for MMC IO.
1997 This will make the mmc core return data errors. This is
1998 useful to test the error handling in the mmc block device
1999 and to test how the mmc host driver handles retries from
2003 bool "Fault-injection capability for SunRPC"
2004 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2006 Provide fault-injection capability for SunRPC and
2009 config FAULT_INJECTION_STACKTRACE_FILTER
2010 bool "stacktrace filter for fault-injection capabilities"
2011 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
2013 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2015 Provide stacktrace filter for fault-injection capabilities
2017 config ARCH_HAS_KCOV
2020 An architecture should select this when it can successfully
2021 build and run with CONFIG_KCOV. This typically requires
2022 disabling instrumentation for some early boot code.
2024 config CC_HAS_SANCOV_TRACE_PC
2025 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2029 bool "Code coverage for fuzzing"
2030 depends on ARCH_HAS_KCOV
2031 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2032 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2033 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
2035 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2036 select OBJTOOL if HAVE_NOINSTR_HACK
2038 KCOV exposes kernel code coverage information in a form suitable
2039 for coverage-guided fuzzing (randomized testing).
2041 If RANDOMIZE_BASE is enabled, PC values will not be stable across
2042 different machines and across reboots. If you need stable PC values,
2043 disable RANDOMIZE_BASE.
2045 For more details, see Documentation/dev-tools/kcov.rst.
2047 config KCOV_ENABLE_COMPARISONS
2048 bool "Enable comparison operands collection by KCOV"
2050 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2052 KCOV also exposes operands of every comparison in the instrumented
2053 code along with operand sizes and PCs of the comparison instructions.
2054 These operands can be used by fuzzing engines to improve the quality
2055 of fuzzing coverage.
2057 config KCOV_INSTRUMENT_ALL
2058 bool "Instrument all code by default"
2062 If you are doing generic system call fuzzing (like e.g. syzkaller),
2063 then you will want to instrument the whole kernel and you should
2064 say y here. If you are doing more targeted fuzzing (like e.g.
2065 filesystem fuzzing with AFL) then you will want to enable coverage
2066 for more specific subsets of files, and should say n here.
2068 config KCOV_IRQ_AREA_SIZE
2069 hex "Size of interrupt coverage collection area in words"
2073 KCOV uses preallocated per-cpu areas to collect coverage from
2074 soft interrupts. This specifies the size of those areas in the
2075 number of unsigned long words.
2077 menuconfig RUNTIME_TESTING_MENU
2078 bool "Runtime Testing"
2081 if RUNTIME_TESTING_MENU
2084 tristate "Linux Kernel Dump Test Tool Module"
2087 This module enables testing of the different dumping mechanisms by
2088 inducing system failures at predefined crash points.
2089 If you don't need it: say N
2090 Choose M here to compile this code as a module. The module will be
2093 Documentation on how to use the module can be found in
2094 Documentation/fault-injection/provoke-crashes.rst
2096 config CPUMASK_KUNIT_TEST
2097 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2099 default KUNIT_ALL_TESTS
2101 Enable to turn on cpumask tests, running at boot or module load time.
2103 For more information on KUnit and unit tests in general, please refer
2104 to the KUnit documentation in Documentation/dev-tools/kunit/.
2108 config TEST_LIST_SORT
2109 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2111 default KUNIT_ALL_TESTS
2113 Enable this to turn on 'list_sort()' function test. This test is
2114 executed only once during system boot (so affects only boot time),
2115 or at module load time.
2119 config TEST_MIN_HEAP
2120 tristate "Min heap test"
2121 depends on DEBUG_KERNEL || m
2123 Enable this to turn on min heap function tests. This test is
2124 executed only once during system boot (so affects only boot time),
2125 or at module load time.
2130 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2132 default KUNIT_ALL_TESTS
2134 This option enables the self-test function of 'sort()' at boot,
2135 or at module load time.
2140 tristate "64bit/32bit division and modulo test"
2141 depends on DEBUG_KERNEL || m
2143 Enable this to turn on 'do_div()' function test. This test is
2144 executed only once during system boot (so affects only boot time),
2145 or at module load time.
2149 config KPROBES_SANITY_TEST
2150 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2151 depends on DEBUG_KERNEL
2154 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2155 default KUNIT_ALL_TESTS
2157 This option provides for testing basic kprobes functionality on
2158 boot. Samples of kprobe and kretprobe are inserted and
2159 verified for functionality.
2161 Say N if you are unsure.
2163 config FPROBE_SANITY_TEST
2164 bool "Self test for fprobe"
2165 depends on DEBUG_KERNEL
2169 This option will enable testing the fprobe when the system boot.
2170 A series of tests are made to verify that the fprobe is functioning
2173 Say N if you are unsure.
2175 config BACKTRACE_SELF_TEST
2176 tristate "Self test for the backtrace code"
2177 depends on DEBUG_KERNEL
2179 This option provides a kernel module that can be used to test
2180 the kernel stack backtrace code. This option is not useful
2181 for distributions or general kernels, but only for kernel
2182 developers working on architecture code.
2184 Note that if you want to also test saved backtraces, you will
2185 have to enable STACKTRACE as well.
2187 Say N if you are unsure.
2189 config TEST_REF_TRACKER
2190 tristate "Self test for reference tracker"
2191 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2194 This option provides a kernel module performing tests
2195 using reference tracker infrastructure.
2197 Say N if you are unsure.
2200 tristate "Red-Black tree test"
2201 depends on DEBUG_KERNEL
2203 A benchmark measuring the performance of the rbtree library.
2204 Also includes rbtree invariant checks.
2206 config REED_SOLOMON_TEST
2207 tristate "Reed-Solomon library test"
2208 depends on DEBUG_KERNEL || m
2210 select REED_SOLOMON_ENC16
2211 select REED_SOLOMON_DEC16
2213 This option enables the self-test function of rslib at boot,
2214 or at module load time.
2218 config INTERVAL_TREE_TEST
2219 tristate "Interval tree test"
2220 depends on DEBUG_KERNEL
2221 select INTERVAL_TREE
2223 A benchmark measuring the performance of the interval tree library
2226 tristate "Per cpu operations test"
2227 depends on m && DEBUG_KERNEL
2229 Enable this option to build test module which validates per-cpu
2234 config ATOMIC64_SELFTEST
2235 tristate "Perform an atomic64_t self-test"
2237 Enable this option to test the atomic64_t functions at boot or
2238 at module load time.
2242 config ASYNC_RAID6_TEST
2243 tristate "Self test for hardware accelerated raid6 recovery"
2244 depends on ASYNC_RAID6_RECOV
2247 This is a one-shot self test that permutes through the
2248 recovery of all the possible two disk failure scenarios for a
2249 N-disk array. Recovery is performed with the asynchronous
2250 raid6 recovery routines, and will optionally use an offload
2251 engine if one is available.
2256 tristate "Test functions located in the hexdump module at runtime"
2258 config STRING_SELFTEST
2259 tristate "Test string functions at runtime"
2261 config TEST_STRING_HELPERS
2262 tristate "Test functions located in the string_helpers module at runtime"
2265 tristate "Test kstrto*() family of functions at runtime"
2268 tristate "Test printf() family of functions at runtime"
2271 tristate "Test scanf() family of functions at runtime"
2274 tristate "Test bitmap_*() family of functions at runtime"
2276 Enable this option to test the bitmap functions at boot.
2281 tristate "Test functions located in the uuid module at runtime"
2284 tristate "Test the XArray code at runtime"
2286 config TEST_MAPLE_TREE
2287 depends on DEBUG_KERNEL
2288 select DEBUG_MAPLE_TREE
2289 tristate "Test the Maple Tree code at runtime"
2291 config TEST_RHASHTABLE
2292 tristate "Perform selftest on resizable hash table"
2294 Enable this option to test the rhashtable functions at boot.
2299 tristate "Perform selftest on IDA functions"
2302 tristate "Perform selftest on priority array manager"
2305 Enable this option to test priority array manager on boot
2310 config TEST_IRQ_TIMINGS
2311 bool "IRQ timings selftest"
2312 depends on IRQ_TIMINGS
2314 Enable this option to test the irq timings code on boot.
2319 tristate "Test module loading with 'hello world' module"
2322 This builds the "test_module" module that emits "Hello, world"
2323 on printk when loaded. It is designed to be used for basic
2324 evaluation of the module loading subsystem (for example when
2325 validating module verification). It lacks any extra dependencies,
2326 and will not normally be loaded by the system unless explicitly
2332 tristate "Test module for compilation of bitops operations"
2335 This builds the "test_bitops" module that is much like the
2336 TEST_LKM module except that it does a basic exercise of the
2337 set/clear_bit macros and get_count_order/long to make sure there are
2338 no compiler warnings from C=1 sparse checker or -Wextra
2339 compilations. It has no dependencies and doesn't run or load unless
2340 explicitly requested by name. for example: modprobe test_bitops.
2345 tristate "Test module for stress/performance analysis of vmalloc allocator"
2350 This builds the "test_vmalloc" module that should be used for
2351 stress and performance analysis. So, any new change for vmalloc
2352 subsystem can be evaluated from performance and stability point
2357 config TEST_USER_COPY
2358 tristate "Test user/kernel boundary protections"
2361 This builds the "test_user_copy" module that runs sanity checks
2362 on the copy_to/from_user infrastructure, making sure basic
2363 user/kernel boundary testing is working. If it fails to load,
2364 a regression has been detected in the user/kernel memory boundary
2370 tristate "Test BPF filter functionality"
2373 This builds the "test_bpf" module that runs various test vectors
2374 against the BPF interpreter or BPF JIT compiler depending on the
2375 current setting. This is in particular useful for BPF JIT compiler
2376 development, but also to run regression tests against changes in
2377 the interpreter code. It also enables test stubs for eBPF maps and
2378 verifier used by user space verifier testsuite.
2382 config TEST_BLACKHOLE_DEV
2383 tristate "Test blackhole netdev functionality"
2386 This builds the "test_blackhole_dev" module that validates the
2387 data path through this blackhole netdev.
2391 config FIND_BIT_BENCHMARK
2392 tristate "Test find_bit functions"
2394 This builds the "test_find_bit" module that measure find_*_bit()
2395 functions performance.
2399 config TEST_FIRMWARE
2400 tristate "Test firmware loading via userspace interface"
2401 depends on FW_LOADER
2403 This builds the "test_firmware" module that creates a userspace
2404 interface for testing firmware loading. This can be used to
2405 control the triggering of firmware loading without needing an
2406 actual firmware-using device. The contents can be rechecked by
2412 tristate "sysctl test driver"
2413 depends on PROC_SYSCTL
2415 This builds the "test_sysctl" module. This driver enables to test the
2416 proc sysctl interfaces available to drivers safely without affecting
2417 production knobs which might alter system functionality.
2421 config BITFIELD_KUNIT
2422 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2424 default KUNIT_ALL_TESTS
2426 Enable this option to test the bitfield functions at boot.
2428 KUnit tests run during boot and output the results to the debug log
2429 in TAP format (http://testanything.org/). Only useful for kernel devs
2430 running the KUnit test harness, and not intended for inclusion into a
2433 For more information on KUnit and unit tests in general please refer
2434 to the KUnit documentation in Documentation/dev-tools/kunit/.
2438 config HASH_KUNIT_TEST
2439 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2441 default KUNIT_ALL_TESTS
2443 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2444 integer (<linux/hash.h>) hash functions on boot.
2446 KUnit tests run during boot and output the results to the debug log
2447 in TAP format (https://testanything.org/). Only useful for kernel devs
2448 running the KUnit test harness, and not intended for inclusion into a
2451 For more information on KUnit and unit tests in general please refer
2452 to the KUnit documentation in Documentation/dev-tools/kunit/.
2454 This is intended to help people writing architecture-specific
2455 optimized versions. If unsure, say N.
2457 config RESOURCE_KUNIT_TEST
2458 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2460 default KUNIT_ALL_TESTS
2462 This builds the resource API unit test.
2463 Tests the logic of API provided by resource.c and ioport.h.
2464 For more information on KUnit and unit tests in general please refer
2465 to the KUnit documentation in Documentation/dev-tools/kunit/.
2469 config SYSCTL_KUNIT_TEST
2470 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2472 default KUNIT_ALL_TESTS
2474 This builds the proc sysctl unit test, which runs on boot.
2475 Tests the API contract and implementation correctness of sysctl.
2476 For more information on KUnit and unit tests in general please refer
2477 to the KUnit documentation in Documentation/dev-tools/kunit/.
2481 config LIST_KUNIT_TEST
2482 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2484 default KUNIT_ALL_TESTS
2486 This builds the linked list KUnit test suite.
2487 It tests that the API and basic functionality of the list_head type
2488 and associated macros.
2490 KUnit tests run during boot and output the results to the debug log
2491 in TAP format (https://testanything.org/). Only useful for kernel devs
2492 running the KUnit test harness, and not intended for inclusion into a
2495 For more information on KUnit and unit tests in general please refer
2496 to the KUnit documentation 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 source "Documentation/Kconfig"
2887 endmenu # Kernel hacking
projects / linux.git / blob