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
758 Say Y here if you want to enable the memory leak
759 detector. The memory allocation/freeing is traced in a way
760 similar to the Boehm's conservative garbage collector, the
761 difference being that the orphan objects are not freed but
762 only shown in /sys/kernel/debug/kmemleak. Enabling this
763 feature will introduce an overhead to memory
764 allocations. See Documentation/dev-tools/kmemleak.rst for more
767 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
768 of finding leaks due to the slab objects poisoning.
770 In order to access the kmemleak file, debugfs needs to be
771 mounted (usually at /sys/kernel/debug).
773 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
774 int "Kmemleak memory pool size"
775 depends on DEBUG_KMEMLEAK
779 Kmemleak must track all the memory allocations to avoid
780 reporting false positives. Since memory may be allocated or
781 freed before kmemleak is fully initialised, use a static pool
782 of metadata objects to track such callbacks. After kmemleak is
783 fully initialised, this memory pool acts as an emergency one
784 if slab allocations fail.
786 config DEBUG_KMEMLEAK_TEST
787 tristate "Simple test for the kernel memory leak detector"
788 depends on DEBUG_KMEMLEAK && m
790 This option enables a module that explicitly leaks memory.
794 config DEBUG_KMEMLEAK_DEFAULT_OFF
795 bool "Default kmemleak to off"
796 depends on DEBUG_KMEMLEAK
798 Say Y here to disable kmemleak by default. It can then be enabled
799 on the command line via kmemleak=on.
801 config DEBUG_KMEMLEAK_AUTO_SCAN
802 bool "Enable kmemleak auto scan thread on boot up"
804 depends on DEBUG_KMEMLEAK
806 Depending on the cpu, kmemleak scan may be cpu intensive and can
807 stall user tasks at times. This option enables/disables automatic
808 kmemleak scan at boot up.
810 Say N here to disable kmemleak auto scan thread to stop automatic
811 scanning. Disabling this option disables automatic reporting of
816 config DEBUG_STACK_USAGE
817 bool "Stack utilization instrumentation"
818 depends on DEBUG_KERNEL && !IA64
820 Enables the display of the minimum amount of free stack which each
821 task has ever had available in the sysrq-T and sysrq-P debug output.
823 This option will slow down process creation somewhat.
825 config SCHED_STACK_END_CHECK
826 bool "Detect stack corruption on calls to schedule()"
827 depends on DEBUG_KERNEL
830 This option checks for a stack overrun on calls to schedule().
831 If the stack end location is found to be over written always panic as
832 the content of the corrupted region can no longer be trusted.
833 This is to ensure no erroneous behaviour occurs which could result in
834 data corruption or a sporadic crash at a later stage once the region
835 is examined. The runtime overhead introduced is minimal.
837 config ARCH_HAS_DEBUG_VM_PGTABLE
840 An architecture should select this when it can successfully
841 build and run DEBUG_VM_PGTABLE.
843 config DEBUG_VM_IRQSOFF
844 def_bool DEBUG_VM && !PREEMPT_RT
848 depends on DEBUG_KERNEL
850 Enable this to turn on extended checks in the virtual-memory system
851 that may impact performance.
855 config DEBUG_VM_MAPLE_TREE
856 bool "Debug VM maple trees"
858 select DEBUG_MAPLE_TREE
860 Enable VM maple tree debugging information and extra validations.
865 bool "Debug VM red-black trees"
868 Enable VM red-black tree debugging information and extra validations.
872 config DEBUG_VM_PGFLAGS
873 bool "Debug page-flags operations"
876 Enables extra validation on page flags operations.
880 config DEBUG_VM_PGTABLE
881 bool "Debug arch page table for semantics compliance"
883 depends on ARCH_HAS_DEBUG_VM_PGTABLE
884 default y if DEBUG_VM
886 This option provides a debug method which can be used to test
887 architecture page table helper functions on various platforms in
888 verifying if they comply with expected generic MM semantics. This
889 will help architecture code in making sure that any changes or
890 new additions of these helpers still conform to expected
891 semantics of the generic MM. Platforms will have to opt in for
892 this through ARCH_HAS_DEBUG_VM_PGTABLE.
896 config ARCH_HAS_DEBUG_VIRTUAL
900 bool "Debug VM translations"
901 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
903 Enable some costly sanity checks in virtual to page code. This can
904 catch mistakes with virt_to_page() and friends.
908 config DEBUG_NOMMU_REGIONS
909 bool "Debug the global anon/private NOMMU mapping region tree"
910 depends on DEBUG_KERNEL && !MMU
912 This option causes the global tree of anonymous and private mapping
913 regions to be regularly checked for invalid topology.
915 config DEBUG_MEMORY_INIT
916 bool "Debug memory initialisation" if EXPERT
919 Enable this for additional checks during memory initialisation.
920 The sanity checks verify aspects of the VM such as the memory model
921 and other information provided by the architecture. Verbose
922 information will be printed at KERN_DEBUG loglevel depending
923 on the mminit_loglevel= command-line option.
927 config MEMORY_NOTIFIER_ERROR_INJECT
928 tristate "Memory hotplug notifier error injection module"
929 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
931 This option provides the ability to inject artificial errors to
932 memory hotplug notifier chain callbacks. It is controlled through
933 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
935 If the notifier call chain should be failed with some events
936 notified, write the error code to "actions/<notifier event>/error".
938 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
940 # cd /sys/kernel/debug/notifier-error-inject/memory
941 # echo -12 > actions/MEM_GOING_OFFLINE/error
942 # echo offline > /sys/devices/system/memory/memoryXXX/state
943 bash: echo: write error: Cannot allocate memory
945 To compile this code as a module, choose M here: the module will
946 be called memory-notifier-error-inject.
950 config DEBUG_PER_CPU_MAPS
951 bool "Debug access to per_cpu maps"
952 depends on DEBUG_KERNEL
955 Say Y to verify that the per_cpu map being accessed has
956 been set up. This adds a fair amount of code to kernel memory
957 and decreases performance.
961 config DEBUG_KMAP_LOCAL
962 bool "Debug kmap_local temporary mappings"
963 depends on DEBUG_KERNEL && KMAP_LOCAL
965 This option enables additional error checking for the kmap_local
966 infrastructure. Disable for production use.
968 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
971 config DEBUG_KMAP_LOCAL_FORCE_MAP
972 bool "Enforce kmap_local temporary mappings"
973 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
975 select DEBUG_KMAP_LOCAL
977 This option enforces temporary mappings through the kmap_local
978 mechanism for non-highmem pages and on non-highmem systems.
979 Disable this for production systems!
982 bool "Highmem debugging"
983 depends on DEBUG_KERNEL && HIGHMEM
984 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
985 select DEBUG_KMAP_LOCAL
987 This option enables additional error checking for high memory
988 systems. Disable for production systems.
990 config HAVE_DEBUG_STACKOVERFLOW
993 config DEBUG_STACKOVERFLOW
994 bool "Check for stack overflows"
995 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
997 Say Y here if you want to check for overflows of kernel, IRQ
998 and exception stacks (if your architecture uses them). This
999 option will show detailed messages if free stack space drops
1000 below a certain limit.
1002 These kinds of bugs usually occur when call-chains in the
1003 kernel get too deep, especially when interrupts are
1006 Use this in cases where you see apparently random memory
1007 corruption, especially if it appears in 'struct thread_info'
1009 If in doubt, say "N".
1011 source "lib/Kconfig.kasan"
1012 source "lib/Kconfig.kfence"
1013 source "lib/Kconfig.kmsan"
1015 endmenu # "Memory Debugging"
1018 bool "Debug shared IRQ handlers"
1019 depends on DEBUG_KERNEL
1021 Enable this to generate a spurious interrupt just before a shared
1022 interrupt handler is deregistered (generating one when registering
1023 is currently disabled). Drivers need to handle this correctly. Some
1024 don't and need to be caught.
1026 menu "Debug Oops, Lockups and Hangs"
1028 config PANIC_ON_OOPS
1029 bool "Panic on Oops"
1031 Say Y here to enable the kernel to panic when it oopses. This
1032 has the same effect as setting oops=panic on the kernel command
1035 This feature is useful to ensure that the kernel does not do
1036 anything erroneous after an oops which could result in data
1037 corruption or other issues.
1041 config PANIC_ON_OOPS_VALUE
1044 default 0 if !PANIC_ON_OOPS
1045 default 1 if PANIC_ON_OOPS
1047 config PANIC_TIMEOUT
1051 Set the timeout value (in seconds) until a reboot occurs when
1052 the kernel panics. If n = 0, then we wait forever. A timeout
1053 value n > 0 will wait n seconds before rebooting, while a timeout
1054 value n < 0 will reboot immediately.
1056 config LOCKUP_DETECTOR
1059 config SOFTLOCKUP_DETECTOR
1060 bool "Detect Soft Lockups"
1061 depends on DEBUG_KERNEL && !S390
1062 select LOCKUP_DETECTOR
1064 Say Y here to enable the kernel to act as a watchdog to detect
1067 Softlockups are bugs that cause the kernel to loop in kernel
1068 mode for more than 20 seconds, without giving other tasks a
1069 chance to run. The current stack trace is displayed upon
1070 detection and the system will stay locked up.
1072 config BOOTPARAM_SOFTLOCKUP_PANIC
1073 bool "Panic (Reboot) On Soft Lockups"
1074 depends on SOFTLOCKUP_DETECTOR
1076 Say Y here to enable the kernel to panic on "soft lockups",
1077 which are bugs that cause the kernel to loop in kernel
1078 mode for more than 20 seconds (configurable using the watchdog_thresh
1079 sysctl), without giving other tasks a chance to run.
1081 The panic can be used in combination with panic_timeout,
1082 to cause the system to reboot automatically after a
1083 lockup has been detected. This feature is useful for
1084 high-availability systems that have uptime guarantees and
1085 where a lockup must be resolved ASAP.
1089 config HARDLOCKUP_DETECTOR_PERF
1091 select SOFTLOCKUP_DETECTOR
1094 # Enables a timestamp based low pass filter to compensate for perf based
1095 # hard lockup detection which runs too fast due to turbo modes.
1097 config HARDLOCKUP_CHECK_TIMESTAMP
1101 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1102 # lockup detector rather than the perf based detector.
1104 config HARDLOCKUP_DETECTOR
1105 bool "Detect Hard Lockups"
1106 depends on DEBUG_KERNEL && !S390
1107 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1108 select LOCKUP_DETECTOR
1109 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1111 Say Y here to enable the kernel to act as a watchdog to detect
1114 Hardlockups are bugs that cause the CPU to loop in kernel mode
1115 for more than 10 seconds, without letting other interrupts have a
1116 chance to run. The current stack trace is displayed upon detection
1117 and the system will stay locked up.
1119 config BOOTPARAM_HARDLOCKUP_PANIC
1120 bool "Panic (Reboot) On Hard Lockups"
1121 depends on HARDLOCKUP_DETECTOR
1123 Say Y here to enable the kernel to panic on "hard lockups",
1124 which are bugs that cause the kernel to loop in kernel
1125 mode with interrupts disabled for more than 10 seconds (configurable
1126 using the watchdog_thresh sysctl).
1130 config DETECT_HUNG_TASK
1131 bool "Detect Hung Tasks"
1132 depends on DEBUG_KERNEL
1133 default SOFTLOCKUP_DETECTOR
1135 Say Y here to enable the kernel to detect "hung tasks",
1136 which are bugs that cause the task to be stuck in
1137 uninterruptible "D" state indefinitely.
1139 When a hung task is detected, the kernel will print the
1140 current stack trace (which you should report), but the
1141 task will stay in uninterruptible state. If lockdep is
1142 enabled then all held locks will also be reported. This
1143 feature has negligible overhead.
1145 config DEFAULT_HUNG_TASK_TIMEOUT
1146 int "Default timeout for hung task detection (in seconds)"
1147 depends on DETECT_HUNG_TASK
1150 This option controls the default timeout (in seconds) used
1151 to determine when a task has become non-responsive and should
1154 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1155 sysctl or by writing a value to
1156 /proc/sys/kernel/hung_task_timeout_secs.
1158 A timeout of 0 disables the check. The default is two minutes.
1159 Keeping the default should be fine in most cases.
1161 config BOOTPARAM_HUNG_TASK_PANIC
1162 bool "Panic (Reboot) On Hung Tasks"
1163 depends on DETECT_HUNG_TASK
1165 Say Y here to enable the kernel to panic on "hung tasks",
1166 which are bugs that cause the kernel to leave a task stuck
1167 in uninterruptible "D" state.
1169 The panic can be used in combination with panic_timeout,
1170 to cause the system to reboot automatically after a
1171 hung task has been detected. This feature is useful for
1172 high-availability systems that have uptime guarantees and
1173 where a hung tasks must be resolved ASAP.
1178 bool "Detect Workqueue Stalls"
1179 depends on DEBUG_KERNEL
1181 Say Y here to enable stall detection on workqueues. If a
1182 worker pool doesn't make forward progress on a pending work
1183 item for over a given amount of time, 30s by default, a
1184 warning message is printed along with dump of workqueue
1185 state. This can be configured through kernel parameter
1186 "workqueue.watchdog_thresh" and its sysfs counterpart.
1189 tristate "Test module to generate lockups"
1192 This builds the "test_lockup" module that helps to make sure
1193 that watchdogs and lockup detectors are working properly.
1195 Depending on module parameters it could emulate soft or hard
1196 lockup, "hung task", or locking arbitrary lock for a long time.
1197 Also it could generate series of lockups with cooling-down periods.
1201 endmenu # "Debug lockups and hangs"
1203 menu "Scheduler Debugging"
1206 bool "Collect scheduler debugging info"
1207 depends on DEBUG_KERNEL && PROC_FS
1210 If you say Y here, the /proc/sched_debug file will be provided
1211 that can help debug the scheduler. The runtime overhead of this
1219 bool "Collect scheduler statistics"
1220 depends on DEBUG_KERNEL && PROC_FS
1223 If you say Y here, additional code will be inserted into the
1224 scheduler and related routines to collect statistics about
1225 scheduler behavior and provide them in /proc/schedstat. These
1226 stats may be useful for both tuning and debugging the scheduler
1227 If you aren't debugging the scheduler or trying to tune a specific
1228 application, you can say N to avoid the very slight overhead
1233 config DEBUG_TIMEKEEPING
1234 bool "Enable extra timekeeping sanity checking"
1236 This option will enable additional timekeeping sanity checks
1237 which may be helpful when diagnosing issues where timekeeping
1238 problems are suspected.
1240 This may include checks in the timekeeping hotpaths, so this
1241 option may have a (very small) performance impact to some
1246 config DEBUG_PREEMPT
1247 bool "Debug preemptible kernel"
1248 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1251 If you say Y here then the kernel will use a debug variant of the
1252 commonly used smp_processor_id() function and will print warnings
1253 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1254 will detect preemption count underflows.
1256 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1258 config LOCK_DEBUGGING_SUPPORT
1260 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1263 config PROVE_LOCKING
1264 bool "Lock debugging: prove locking correctness"
1265 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1267 select DEBUG_SPINLOCK
1268 select DEBUG_MUTEXES if !PREEMPT_RT
1269 select DEBUG_RT_MUTEXES if RT_MUTEXES
1271 select DEBUG_WW_MUTEX_SLOWPATH
1272 select DEBUG_LOCK_ALLOC
1273 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1274 select TRACE_IRQFLAGS
1277 This feature enables the kernel to prove that all locking
1278 that occurs in the kernel runtime is mathematically
1279 correct: that under no circumstance could an arbitrary (and
1280 not yet triggered) combination of observed locking
1281 sequences (on an arbitrary number of CPUs, running an
1282 arbitrary number of tasks and interrupt contexts) cause a
1285 In short, this feature enables the kernel to report locking
1286 related deadlocks before they actually occur.
1288 The proof does not depend on how hard and complex a
1289 deadlock scenario would be to trigger: how many
1290 participant CPUs, tasks and irq-contexts would be needed
1291 for it to trigger. The proof also does not depend on
1292 timing: if a race and a resulting deadlock is possible
1293 theoretically (no matter how unlikely the race scenario
1294 is), it will be proven so and will immediately be
1295 reported by the kernel (once the event is observed that
1296 makes the deadlock theoretically possible).
1298 If a deadlock is impossible (i.e. the locking rules, as
1299 observed by the kernel, are mathematically correct), the
1300 kernel reports nothing.
1302 NOTE: this feature can also be enabled for rwlocks, mutexes
1303 and rwsems - in which case all dependencies between these
1304 different locking variants are observed and mapped too, and
1305 the proof of observed correctness is also maintained for an
1306 arbitrary combination of these separate locking variants.
1308 For more details, see Documentation/locking/lockdep-design.rst.
1310 config PROVE_RAW_LOCK_NESTING
1311 bool "Enable raw_spinlock - spinlock nesting checks"
1312 depends on PROVE_LOCKING
1315 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1316 that the lock nesting rules for PREEMPT_RT enabled kernels are
1319 NOTE: There are known nesting problems. So if you enable this
1320 option expect lockdep splats until these problems have been fully
1321 addressed which is work in progress. This config switch allows to
1322 identify and analyze these problems. It will be removed and the
1323 check permanently enabled once the main issues have been fixed.
1325 If unsure, select N.
1328 bool "Lock usage statistics"
1329 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1331 select DEBUG_SPINLOCK
1332 select DEBUG_MUTEXES if !PREEMPT_RT
1333 select DEBUG_RT_MUTEXES if RT_MUTEXES
1334 select DEBUG_LOCK_ALLOC
1337 This feature enables tracking lock contention points
1339 For more details, see Documentation/locking/lockstat.rst
1341 This also enables lock events required by "perf lock",
1343 If you want to use "perf lock", you also need to turn on
1344 CONFIG_EVENT_TRACING.
1346 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1347 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1349 config DEBUG_RT_MUTEXES
1350 bool "RT Mutex debugging, deadlock detection"
1351 depends on DEBUG_KERNEL && RT_MUTEXES
1353 This allows rt mutex semantics violations and rt mutex related
1354 deadlocks (lockups) to be detected and reported automatically.
1356 config DEBUG_SPINLOCK
1357 bool "Spinlock and rw-lock debugging: basic checks"
1358 depends on DEBUG_KERNEL
1359 select UNINLINE_SPIN_UNLOCK
1361 Say Y here and build SMP to catch missing spinlock initialization
1362 and certain other kinds of spinlock errors commonly made. This is
1363 best used in conjunction with the NMI watchdog so that spinlock
1364 deadlocks are also debuggable.
1366 config DEBUG_MUTEXES
1367 bool "Mutex debugging: basic checks"
1368 depends on DEBUG_KERNEL && !PREEMPT_RT
1370 This feature allows mutex semantics violations to be detected and
1373 config DEBUG_WW_MUTEX_SLOWPATH
1374 bool "Wait/wound mutex debugging: Slowpath testing"
1375 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1376 select DEBUG_LOCK_ALLOC
1377 select DEBUG_SPINLOCK
1378 select DEBUG_MUTEXES if !PREEMPT_RT
1379 select DEBUG_RT_MUTEXES if PREEMPT_RT
1381 This feature enables slowpath testing for w/w mutex users by
1382 injecting additional -EDEADLK wound/backoff cases. Together with
1383 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1384 will test all possible w/w mutex interface abuse with the
1385 exception of simply not acquiring all the required locks.
1386 Note that this feature can introduce significant overhead, so
1387 it really should not be enabled in a production or distro kernel,
1388 even a debug kernel. If you are a driver writer, enable it. If
1389 you are a distro, do not.
1392 bool "RW Semaphore debugging: basic checks"
1393 depends on DEBUG_KERNEL
1395 This debugging feature allows mismatched rw semaphore locks
1396 and unlocks to be detected and reported.
1398 config DEBUG_LOCK_ALLOC
1399 bool "Lock debugging: detect incorrect freeing of live locks"
1400 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1401 select DEBUG_SPINLOCK
1402 select DEBUG_MUTEXES if !PREEMPT_RT
1403 select DEBUG_RT_MUTEXES if RT_MUTEXES
1406 This feature will check whether any held lock (spinlock, rwlock,
1407 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1408 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1409 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1410 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1411 held during task exit.
1415 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1420 config LOCKDEP_SMALL
1424 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1425 depends on LOCKDEP && !LOCKDEP_SMALL
1429 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1431 config LOCKDEP_CHAINS_BITS
1432 int "Bitsize for MAX_LOCKDEP_CHAINS"
1433 depends on LOCKDEP && !LOCKDEP_SMALL
1437 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1439 config LOCKDEP_STACK_TRACE_BITS
1440 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1441 depends on LOCKDEP && !LOCKDEP_SMALL
1445 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1447 config LOCKDEP_STACK_TRACE_HASH_BITS
1448 int "Bitsize for STACK_TRACE_HASH_SIZE"
1449 depends on LOCKDEP && !LOCKDEP_SMALL
1453 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1455 config LOCKDEP_CIRCULAR_QUEUE_BITS
1456 int "Bitsize for elements in circular_queue struct"
1461 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1463 config DEBUG_LOCKDEP
1464 bool "Lock dependency engine debugging"
1465 depends on DEBUG_KERNEL && LOCKDEP
1466 select DEBUG_IRQFLAGS
1468 If you say Y here, the lock dependency engine will do
1469 additional runtime checks to debug itself, at the price
1470 of more runtime overhead.
1472 config DEBUG_ATOMIC_SLEEP
1473 bool "Sleep inside atomic section checking"
1474 select PREEMPT_COUNT
1475 depends on DEBUG_KERNEL
1476 depends on !ARCH_NO_PREEMPT
1478 If you say Y here, various routines which may sleep will become very
1479 noisy if they are called inside atomic sections: when a spinlock is
1480 held, inside an rcu read side critical section, inside preempt disabled
1481 sections, inside an interrupt, etc...
1483 config DEBUG_LOCKING_API_SELFTESTS
1484 bool "Locking API boot-time self-tests"
1485 depends on DEBUG_KERNEL
1487 Say Y here if you want the kernel to run a short self-test during
1488 bootup. The self-test checks whether common types of locking bugs
1489 are detected by debugging mechanisms or not. (if you disable
1490 lock debugging then those bugs won't be detected of course.)
1491 The following locking APIs are covered: spinlocks, rwlocks,
1494 config LOCK_TORTURE_TEST
1495 tristate "torture tests for locking"
1496 depends on DEBUG_KERNEL
1499 This option provides a kernel module that runs torture tests
1500 on kernel locking primitives. The kernel module may be built
1501 after the fact on the running kernel to be tested, if desired.
1503 Say Y here if you want kernel locking-primitive torture tests
1504 to be built into the kernel.
1505 Say M if you want these torture tests to build as a module.
1506 Say N if you are unsure.
1508 config WW_MUTEX_SELFTEST
1509 tristate "Wait/wound mutex selftests"
1511 This option provides a kernel module that runs tests on the
1512 on the struct ww_mutex locking API.
1514 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1515 with this test harness.
1517 Say M if you want these self tests to build as a module.
1518 Say N if you are unsure.
1520 config SCF_TORTURE_TEST
1521 tristate "torture tests for smp_call_function*()"
1522 depends on DEBUG_KERNEL
1525 This option provides a kernel module that runs torture tests
1526 on the smp_call_function() family of primitives. The kernel
1527 module may be built after the fact on the running kernel to
1528 be tested, if desired.
1530 config CSD_LOCK_WAIT_DEBUG
1531 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1532 depends on DEBUG_KERNEL
1536 This option enables debug prints when CPUs are slow to respond
1537 to the smp_call_function*() IPI wrappers. These debug prints
1538 include the IPI handler function currently executing (if any)
1539 and relevant stack traces.
1541 endmenu # lock debugging
1543 config TRACE_IRQFLAGS
1544 depends on TRACE_IRQFLAGS_SUPPORT
1547 Enables hooks to interrupt enabling and disabling for
1548 either tracing or lock debugging.
1550 config TRACE_IRQFLAGS_NMI
1552 depends on TRACE_IRQFLAGS
1553 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1555 config DEBUG_IRQFLAGS
1556 bool "Debug IRQ flag manipulation"
1558 Enables checks for potentially unsafe enabling or disabling of
1559 interrupts, such as calling raw_local_irq_restore() when interrupts
1563 bool "Stack backtrace support"
1564 depends on STACKTRACE_SUPPORT
1566 This option causes the kernel to create a /proc/pid/stack for
1567 every process, showing its current stack trace.
1568 It is also used by various kernel debugging features that require
1569 stack trace generation.
1571 config WARN_ALL_UNSEEDED_RANDOM
1572 bool "Warn for all uses of unseeded randomness"
1575 Some parts of the kernel contain bugs relating to their use of
1576 cryptographically secure random numbers before it's actually possible
1577 to generate those numbers securely. This setting ensures that these
1578 flaws don't go unnoticed, by enabling a message, should this ever
1579 occur. This will allow people with obscure setups to know when things
1580 are going wrong, so that they might contact developers about fixing
1583 Unfortunately, on some models of some architectures getting
1584 a fully seeded CRNG is extremely difficult, and so this can
1585 result in dmesg getting spammed for a surprisingly long
1586 time. This is really bad from a security perspective, and
1587 so architecture maintainers really need to do what they can
1588 to get the CRNG seeded sooner after the system is booted.
1589 However, since users cannot do anything actionable to
1590 address this, by default this option is disabled.
1592 Say Y here if you want to receive warnings for all uses of
1593 unseeded randomness. This will be of use primarily for
1594 those developers interested in improving the security of
1595 Linux kernels running on their architecture (or
1598 config DEBUG_KOBJECT
1599 bool "kobject debugging"
1600 depends on DEBUG_KERNEL
1602 If you say Y here, some extra kobject debugging messages will be sent
1605 config DEBUG_KOBJECT_RELEASE
1606 bool "kobject release debugging"
1607 depends on DEBUG_OBJECTS_TIMERS
1609 kobjects are reference counted objects. This means that their
1610 last reference count put is not predictable, and the kobject can
1611 live on past the point at which a driver decides to drop its
1612 initial reference to the kobject gained on allocation. An
1613 example of this would be a struct device which has just been
1616 However, some buggy drivers assume that after such an operation,
1617 the memory backing the kobject can be immediately freed. This
1618 goes completely against the principles of a refcounted object.
1620 If you say Y here, the kernel will delay the release of kobjects
1621 on the last reference count to improve the visibility of this
1622 kind of kobject release bug.
1624 config HAVE_DEBUG_BUGVERBOSE
1627 menu "Debug kernel data structures"
1630 bool "Debug linked list manipulation"
1631 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1633 Enable this to turn on extended checks in the linked-list
1639 bool "Debug priority linked list manipulation"
1640 depends on DEBUG_KERNEL
1642 Enable this to turn on extended checks in the priority-ordered
1643 linked-list (plist) walking routines. This checks the entire
1644 list multiple times during each manipulation.
1649 bool "Debug SG table operations"
1650 depends on DEBUG_KERNEL
1652 Enable this to turn on checks on scatter-gather tables. This can
1653 help find problems with drivers that do not properly initialize
1658 config DEBUG_NOTIFIERS
1659 bool "Debug notifier call chains"
1660 depends on DEBUG_KERNEL
1662 Enable this to turn on sanity checking for notifier call chains.
1663 This is most useful for kernel developers to make sure that
1664 modules properly unregister themselves from notifier chains.
1665 This is a relatively cheap check but if you care about maximum
1668 config BUG_ON_DATA_CORRUPTION
1669 bool "Trigger a BUG when data corruption is detected"
1672 Select this option if the kernel should BUG when it encounters
1673 data corruption in kernel memory structures when they get checked
1678 config DEBUG_MAPLE_TREE
1679 bool "Debug maple trees"
1680 depends on DEBUG_KERNEL
1682 Enable maple tree debugging information and extra validations.
1688 config DEBUG_CREDENTIALS
1689 bool "Debug credential management"
1690 depends on DEBUG_KERNEL
1692 Enable this to turn on some debug checking for credential
1693 management. The additional code keeps track of the number of
1694 pointers from task_structs to any given cred struct, and checks to
1695 see that this number never exceeds the usage count of the cred
1698 Furthermore, if SELinux is enabled, this also checks that the
1699 security pointer in the cred struct is never seen to be invalid.
1703 source "kernel/rcu/Kconfig.debug"
1705 config DEBUG_WQ_FORCE_RR_CPU
1706 bool "Force round-robin CPU selection for unbound work items"
1707 depends on DEBUG_KERNEL
1710 Workqueue used to implicitly guarantee that work items queued
1711 without explicit CPU specified are put on the local CPU. This
1712 guarantee is no longer true and while local CPU is still
1713 preferred work items may be put on foreign CPUs. Kernel
1714 parameter "workqueue.debug_force_rr_cpu" is added to force
1715 round-robin CPU selection to flush out usages which depend on the
1716 now broken guarantee. This config option enables the debug
1717 feature by default. When enabled, memory and cache locality will
1720 config CPU_HOTPLUG_STATE_CONTROL
1721 bool "Enable CPU hotplug state control"
1722 depends on DEBUG_KERNEL
1723 depends on HOTPLUG_CPU
1726 Allows to write steps between "offline" and "online" to the CPUs
1727 sysfs target file so states can be stepped granular. This is a debug
1728 option for now as the hotplug machinery cannot be stopped and
1729 restarted at arbitrary points yet.
1731 Say N if your are unsure.
1734 bool "Latency measuring infrastructure"
1735 depends on DEBUG_KERNEL
1736 depends on STACKTRACE_SUPPORT
1738 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1744 Enable this option if you want to use the LatencyTOP tool
1745 to find out which userspace is blocking on what kernel operations.
1747 config DEBUG_CGROUP_REF
1748 bool "Disable inlining of cgroup css reference count functions"
1749 depends on DEBUG_KERNEL
1754 Force cgroup css reference count functions to not be inlined so
1755 that they can be kprobed for debugging.
1757 source "kernel/trace/Kconfig"
1759 config PROVIDE_OHCI1394_DMA_INIT
1760 bool "Remote debugging over FireWire early on boot"
1761 depends on PCI && X86
1763 If you want to debug problems which hang or crash the kernel early
1764 on boot and the crashing machine has a FireWire port, you can use
1765 this feature to remotely access the memory of the crashed machine
1766 over FireWire. This employs remote DMA as part of the OHCI1394
1767 specification which is now the standard for FireWire controllers.
1769 With remote DMA, you can monitor the printk buffer remotely using
1770 firescope and access all memory below 4GB using fireproxy from gdb.
1771 Even controlling a kernel debugger is possible using remote DMA.
1775 If ohci1394_dma=early is used as boot parameter, it will initialize
1776 all OHCI1394 controllers which are found in the PCI config space.
1778 As all changes to the FireWire bus such as enabling and disabling
1779 devices cause a bus reset and thereby disable remote DMA for all
1780 devices, be sure to have the cable plugged and FireWire enabled on
1781 the debugging host before booting the debug target for debugging.
1783 This code (~1k) is freed after boot. By then, the firewire stack
1784 in charge of the OHCI-1394 controllers should be used instead.
1786 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1788 source "samples/Kconfig"
1790 config ARCH_HAS_DEVMEM_IS_ALLOWED
1793 config STRICT_DEVMEM
1794 bool "Filter access to /dev/mem"
1795 depends on MMU && DEVMEM
1796 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1797 default y if PPC || X86 || ARM64
1799 If this option is disabled, you allow userspace (root) access to all
1800 of memory, including kernel and userspace memory. Accidental
1801 access to this is obviously disastrous, but specific access can
1802 be used by people debugging the kernel. Note that with PAT support
1803 enabled, even in this case there are restrictions on /dev/mem
1804 use due to the cache aliasing requirements.
1806 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1807 file only allows userspace access to PCI space and the BIOS code and
1808 data regions. This is sufficient for dosemu and X and all common
1813 config IO_STRICT_DEVMEM
1814 bool "Filter I/O access to /dev/mem"
1815 depends on STRICT_DEVMEM
1817 If this option is disabled, you allow userspace (root) access to all
1818 io-memory regardless of whether a driver is actively using that
1819 range. Accidental access to this is obviously disastrous, but
1820 specific access can be used by people debugging kernel drivers.
1822 If this option is switched on, the /dev/mem file only allows
1823 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1824 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1825 if the driver using a given range cannot be disabled.
1829 menu "$(SRCARCH) Debugging"
1831 source "arch/$(SRCARCH)/Kconfig.debug"
1835 menu "Kernel Testing and Coverage"
1837 source "lib/kunit/Kconfig"
1839 config NOTIFIER_ERROR_INJECTION
1840 tristate "Notifier error injection"
1841 depends on DEBUG_KERNEL
1844 This option provides the ability to inject artificial errors to
1845 specified notifier chain callbacks. It is useful to test the error
1846 handling of notifier call chain failures.
1850 config PM_NOTIFIER_ERROR_INJECT
1851 tristate "PM notifier error injection module"
1852 depends on PM && NOTIFIER_ERROR_INJECTION
1853 default m if PM_DEBUG
1855 This option provides the ability to inject artificial errors to
1856 PM notifier chain callbacks. It is controlled through debugfs
1857 interface /sys/kernel/debug/notifier-error-inject/pm
1859 If the notifier call chain should be failed with some events
1860 notified, write the error code to "actions/<notifier event>/error".
1862 Example: Inject PM suspend error (-12 = -ENOMEM)
1864 # cd /sys/kernel/debug/notifier-error-inject/pm/
1865 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1866 # echo mem > /sys/power/state
1867 bash: echo: write error: Cannot allocate memory
1869 To compile this code as a module, choose M here: the module will
1870 be called pm-notifier-error-inject.
1874 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1875 tristate "OF reconfig notifier error injection module"
1876 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1878 This option provides the ability to inject artificial errors to
1879 OF reconfig notifier chain callbacks. It is controlled
1880 through debugfs interface under
1881 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1883 If the notifier call chain should be failed with some events
1884 notified, write the error code to "actions/<notifier event>/error".
1886 To compile this code as a module, choose M here: the module will
1887 be called of-reconfig-notifier-error-inject.
1891 config NETDEV_NOTIFIER_ERROR_INJECT
1892 tristate "Netdev notifier error injection module"
1893 depends on NET && NOTIFIER_ERROR_INJECTION
1895 This option provides the ability to inject artificial errors to
1896 netdevice notifier chain callbacks. It is controlled through debugfs
1897 interface /sys/kernel/debug/notifier-error-inject/netdev
1899 If the notifier call chain should be failed with some events
1900 notified, write the error code to "actions/<notifier event>/error".
1902 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1904 # cd /sys/kernel/debug/notifier-error-inject/netdev
1905 # echo -22 > actions/NETDEV_CHANGEMTU/error
1906 # ip link set eth0 mtu 1024
1907 RTNETLINK answers: Invalid argument
1909 To compile this code as a module, choose M here: the module will
1910 be called netdev-notifier-error-inject.
1914 config FUNCTION_ERROR_INJECTION
1915 bool "Fault-injections of functions"
1916 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1918 Add fault injections into various functions that are annotated with
1919 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
1920 value of theses functions. This is useful to test error paths of code.
1924 config FAULT_INJECTION
1925 bool "Fault-injection framework"
1926 depends on DEBUG_KERNEL
1928 Provide fault-injection framework.
1929 For more details, see Documentation/fault-injection/.
1932 bool "Fault-injection capability for kmalloc"
1933 depends on FAULT_INJECTION
1934 depends on SLAB || SLUB
1936 Provide fault-injection capability for kmalloc.
1938 config FAIL_PAGE_ALLOC
1939 bool "Fault-injection capability for alloc_pages()"
1940 depends on FAULT_INJECTION
1942 Provide fault-injection capability for alloc_pages().
1944 config FAULT_INJECTION_USERCOPY
1945 bool "Fault injection capability for usercopy functions"
1946 depends on FAULT_INJECTION
1948 Provides fault-injection capability to inject failures
1949 in usercopy functions (copy_from_user(), get_user(), ...).
1951 config FAIL_MAKE_REQUEST
1952 bool "Fault-injection capability for disk IO"
1953 depends on FAULT_INJECTION && BLOCK
1955 Provide fault-injection capability for disk IO.
1957 config FAIL_IO_TIMEOUT
1958 bool "Fault-injection capability for faking disk interrupts"
1959 depends on FAULT_INJECTION && BLOCK
1961 Provide fault-injection capability on end IO handling. This
1962 will make the block layer "forget" an interrupt as configured,
1963 thus exercising the error handling.
1965 Only works with drivers that use the generic timeout handling,
1966 for others it won't do anything.
1969 bool "Fault-injection capability for futexes"
1971 depends on FAULT_INJECTION && FUTEX
1973 Provide fault-injection capability for futexes.
1975 config FAULT_INJECTION_DEBUG_FS
1976 bool "Debugfs entries for fault-injection capabilities"
1977 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1979 Enable configuration of fault-injection capabilities via debugfs.
1981 config FAIL_FUNCTION
1982 bool "Fault-injection capability for functions"
1983 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1985 Provide function-based fault-injection capability.
1986 This will allow you to override a specific function with a return
1987 with given return value. As a result, function caller will see
1988 an error value and have to handle it. This is useful to test the
1989 error handling in various subsystems.
1991 config FAIL_MMC_REQUEST
1992 bool "Fault-injection capability for MMC IO"
1993 depends on FAULT_INJECTION_DEBUG_FS && MMC
1995 Provide fault-injection capability for MMC IO.
1996 This will make the mmc core return data errors. This is
1997 useful to test the error handling in the mmc block device
1998 and to test how the mmc host driver handles retries from
2002 bool "Fault-injection capability for SunRPC"
2003 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2005 Provide fault-injection capability for SunRPC and
2008 config FAULT_INJECTION_STACKTRACE_FILTER
2009 bool "stacktrace filter for fault-injection capabilities"
2010 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
2012 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2014 Provide stacktrace filter for fault-injection capabilities
2016 config ARCH_HAS_KCOV
2019 An architecture should select this when it can successfully
2020 build and run with CONFIG_KCOV. This typically requires
2021 disabling instrumentation for some early boot code.
2023 config CC_HAS_SANCOV_TRACE_PC
2024 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2028 bool "Code coverage for fuzzing"
2029 depends on ARCH_HAS_KCOV
2030 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2031 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2032 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
2034 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2035 select OBJTOOL if HAVE_NOINSTR_HACK
2037 KCOV exposes kernel code coverage information in a form suitable
2038 for coverage-guided fuzzing (randomized testing).
2040 If RANDOMIZE_BASE is enabled, PC values will not be stable across
2041 different machines and across reboots. If you need stable PC values,
2042 disable RANDOMIZE_BASE.
2044 For more details, see Documentation/dev-tools/kcov.rst.
2046 config KCOV_ENABLE_COMPARISONS
2047 bool "Enable comparison operands collection by KCOV"
2049 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2051 KCOV also exposes operands of every comparison in the instrumented
2052 code along with operand sizes and PCs of the comparison instructions.
2053 These operands can be used by fuzzing engines to improve the quality
2054 of fuzzing coverage.
2056 config KCOV_INSTRUMENT_ALL
2057 bool "Instrument all code by default"
2061 If you are doing generic system call fuzzing (like e.g. syzkaller),
2062 then you will want to instrument the whole kernel and you should
2063 say y here. If you are doing more targeted fuzzing (like e.g.
2064 filesystem fuzzing with AFL) then you will want to enable coverage
2065 for more specific subsets of files, and should say n here.
2067 config KCOV_IRQ_AREA_SIZE
2068 hex "Size of interrupt coverage collection area in words"
2072 KCOV uses preallocated per-cpu areas to collect coverage from
2073 soft interrupts. This specifies the size of those areas in the
2074 number of unsigned long words.
2076 menuconfig RUNTIME_TESTING_MENU
2077 bool "Runtime Testing"
2080 if RUNTIME_TESTING_MENU
2083 tristate "Linux Kernel Dump Test Tool Module"
2086 This module enables testing of the different dumping mechanisms by
2087 inducing system failures at predefined crash points.
2088 If you don't need it: say N
2089 Choose M here to compile this code as a module. The module will be
2092 Documentation on how to use the module can be found in
2093 Documentation/fault-injection/provoke-crashes.rst
2095 config CPUMASK_KUNIT_TEST
2096 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2098 default KUNIT_ALL_TESTS
2100 Enable to turn on cpumask tests, running at boot or module load time.
2102 For more information on KUnit and unit tests in general, please refer
2103 to the KUnit documentation in Documentation/dev-tools/kunit/.
2107 config TEST_LIST_SORT
2108 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2110 default KUNIT_ALL_TESTS
2112 Enable this to turn on 'list_sort()' function test. This test is
2113 executed only once during system boot (so affects only boot time),
2114 or at module load time.
2118 config TEST_MIN_HEAP
2119 tristate "Min heap test"
2120 depends on DEBUG_KERNEL || m
2122 Enable this to turn on min heap function tests. This test is
2123 executed only once during system boot (so affects only boot time),
2124 or at module load time.
2129 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2131 default KUNIT_ALL_TESTS
2133 This option enables the self-test function of 'sort()' at boot,
2134 or at module load time.
2139 tristate "64bit/32bit division and modulo test"
2140 depends on DEBUG_KERNEL || m
2142 Enable this to turn on 'do_div()' function test. This test is
2143 executed only once during system boot (so affects only boot time),
2144 or at module load time.
2148 config KPROBES_SANITY_TEST
2149 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2150 depends on DEBUG_KERNEL
2153 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2154 default KUNIT_ALL_TESTS
2156 This option provides for testing basic kprobes functionality on
2157 boot. Samples of kprobe and kretprobe are inserted and
2158 verified for functionality.
2160 Say N if you are unsure.
2162 config FPROBE_SANITY_TEST
2163 bool "Self test for fprobe"
2164 depends on DEBUG_KERNEL
2168 This option will enable testing the fprobe when the system boot.
2169 A series of tests are made to verify that the fprobe is functioning
2172 Say N if you are unsure.
2174 config BACKTRACE_SELF_TEST
2175 tristate "Self test for the backtrace code"
2176 depends on DEBUG_KERNEL
2178 This option provides a kernel module that can be used to test
2179 the kernel stack backtrace code. This option is not useful
2180 for distributions or general kernels, but only for kernel
2181 developers working on architecture code.
2183 Note that if you want to also test saved backtraces, you will
2184 have to enable STACKTRACE as well.
2186 Say N if you are unsure.
2188 config TEST_REF_TRACKER
2189 tristate "Self test for reference tracker"
2190 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2193 This option provides a kernel module performing tests
2194 using reference tracker infrastructure.
2196 Say N if you are unsure.
2199 tristate "Red-Black tree test"
2200 depends on DEBUG_KERNEL
2202 A benchmark measuring the performance of the rbtree library.
2203 Also includes rbtree invariant checks.
2205 config REED_SOLOMON_TEST
2206 tristate "Reed-Solomon library test"
2207 depends on DEBUG_KERNEL || m
2209 select REED_SOLOMON_ENC16
2210 select REED_SOLOMON_DEC16
2212 This option enables the self-test function of rslib at boot,
2213 or at module load time.
2217 config INTERVAL_TREE_TEST
2218 tristate "Interval tree test"
2219 depends on DEBUG_KERNEL
2220 select INTERVAL_TREE
2222 A benchmark measuring the performance of the interval tree library
2225 tristate "Per cpu operations test"
2226 depends on m && DEBUG_KERNEL
2228 Enable this option to build test module which validates per-cpu
2233 config ATOMIC64_SELFTEST
2234 tristate "Perform an atomic64_t self-test"
2236 Enable this option to test the atomic64_t functions at boot or
2237 at module load time.
2241 config ASYNC_RAID6_TEST
2242 tristate "Self test for hardware accelerated raid6 recovery"
2243 depends on ASYNC_RAID6_RECOV
2246 This is a one-shot self test that permutes through the
2247 recovery of all the possible two disk failure scenarios for a
2248 N-disk array. Recovery is performed with the asynchronous
2249 raid6 recovery routines, and will optionally use an offload
2250 engine if one is available.
2255 tristate "Test functions located in the hexdump module at runtime"
2257 config STRING_SELFTEST
2258 tristate "Test string functions at runtime"
2260 config TEST_STRING_HELPERS
2261 tristate "Test functions located in the string_helpers module at runtime"
2264 tristate "Test kstrto*() family of functions at runtime"
2267 tristate "Test printf() family of functions at runtime"
2270 tristate "Test scanf() family of functions at runtime"
2273 tristate "Test bitmap_*() family of functions at runtime"
2275 Enable this option to test the bitmap functions at boot.
2280 tristate "Test functions located in the uuid module at runtime"
2283 tristate "Test the XArray code at runtime"
2285 config TEST_MAPLE_TREE
2286 depends on DEBUG_KERNEL
2287 select DEBUG_MAPLE_TREE
2288 tristate "Test the Maple Tree code at runtime"
2290 config TEST_RHASHTABLE
2291 tristate "Perform selftest on resizable hash table"
2293 Enable this option to test the rhashtable functions at boot.
2298 tristate "Perform selftest on IDA functions"
2301 tristate "Perform selftest on priority array manager"
2304 Enable this option to test priority array manager on boot
2309 config TEST_IRQ_TIMINGS
2310 bool "IRQ timings selftest"
2311 depends on IRQ_TIMINGS
2313 Enable this option to test the irq timings code on boot.
2318 tristate "Test module loading with 'hello world' module"
2321 This builds the "test_module" module that emits "Hello, world"
2322 on printk when loaded. It is designed to be used for basic
2323 evaluation of the module loading subsystem (for example when
2324 validating module verification). It lacks any extra dependencies,
2325 and will not normally be loaded by the system unless explicitly
2331 tristate "Test module for compilation of bitops operations"
2334 This builds the "test_bitops" module that is much like the
2335 TEST_LKM module except that it does a basic exercise of the
2336 set/clear_bit macros and get_count_order/long to make sure there are
2337 no compiler warnings from C=1 sparse checker or -Wextra
2338 compilations. It has no dependencies and doesn't run or load unless
2339 explicitly requested by name. for example: modprobe test_bitops.
2344 tristate "Test module for stress/performance analysis of vmalloc allocator"
2349 This builds the "test_vmalloc" module that should be used for
2350 stress and performance analysis. So, any new change for vmalloc
2351 subsystem can be evaluated from performance and stability point
2356 config TEST_USER_COPY
2357 tristate "Test user/kernel boundary protections"
2360 This builds the "test_user_copy" module that runs sanity checks
2361 on the copy_to/from_user infrastructure, making sure basic
2362 user/kernel boundary testing is working. If it fails to load,
2363 a regression has been detected in the user/kernel memory boundary
2369 tristate "Test BPF filter functionality"
2372 This builds the "test_bpf" module that runs various test vectors
2373 against the BPF interpreter or BPF JIT compiler depending on the
2374 current setting. This is in particular useful for BPF JIT compiler
2375 development, but also to run regression tests against changes in
2376 the interpreter code. It also enables test stubs for eBPF maps and
2377 verifier used by user space verifier testsuite.
2381 config TEST_BLACKHOLE_DEV
2382 tristate "Test blackhole netdev functionality"
2385 This builds the "test_blackhole_dev" module that validates the
2386 data path through this blackhole netdev.
2390 config FIND_BIT_BENCHMARK
2391 tristate "Test find_bit functions"
2393 This builds the "test_find_bit" module that measure find_*_bit()
2394 functions performance.
2398 config TEST_FIRMWARE
2399 tristate "Test firmware loading via userspace interface"
2400 depends on FW_LOADER
2402 This builds the "test_firmware" module that creates a userspace
2403 interface for testing firmware loading. This can be used to
2404 control the triggering of firmware loading without needing an
2405 actual firmware-using device. The contents can be rechecked by
2411 tristate "sysctl test driver"
2412 depends on PROC_SYSCTL
2414 This builds the "test_sysctl" module. This driver enables to test the
2415 proc sysctl interfaces available to drivers safely without affecting
2416 production knobs which might alter system functionality.
2420 config BITFIELD_KUNIT
2421 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2423 default KUNIT_ALL_TESTS
2425 Enable this option to test the bitfield functions at boot.
2427 KUnit tests run during boot and output the results to the debug log
2428 in TAP format (http://testanything.org/). Only useful for kernel devs
2429 running the KUnit test harness, and not intended for inclusion into a
2432 For more information on KUnit and unit tests in general please refer
2433 to the KUnit documentation in Documentation/dev-tools/kunit/.
2437 config HASH_KUNIT_TEST
2438 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2440 default KUNIT_ALL_TESTS
2442 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2443 integer (<linux/hash.h>) hash functions on boot.
2445 KUnit tests run during boot and output the results to the debug log
2446 in TAP format (https://testanything.org/). Only useful for kernel devs
2447 running the KUnit test harness, and not intended for inclusion into a
2450 For more information on KUnit and unit tests in general please refer
2451 to the KUnit documentation in Documentation/dev-tools/kunit/.
2453 This is intended to help people writing architecture-specific
2454 optimized versions. If unsure, say N.
2456 config RESOURCE_KUNIT_TEST
2457 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2459 default KUNIT_ALL_TESTS
2461 This builds the resource API unit test.
2462 Tests the logic of API provided by resource.c and ioport.h.
2463 For more information on KUnit and unit tests in general please refer
2464 to the KUnit documentation in Documentation/dev-tools/kunit/.
2468 config SYSCTL_KUNIT_TEST
2469 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2471 default KUNIT_ALL_TESTS
2473 This builds the proc sysctl unit test, which runs on boot.
2474 Tests the API contract and implementation correctness of sysctl.
2475 For more information on KUnit and unit tests in general please refer
2476 to the KUnit documentation in Documentation/dev-tools/kunit/.
2480 config LIST_KUNIT_TEST
2481 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2483 default KUNIT_ALL_TESTS
2485 This builds the linked list KUnit test suite.
2486 It tests that the API and basic functionality of the list_head type
2487 and associated macros.
2489 KUnit tests run during boot and output the results to the debug log
2490 in TAP format (https://testanything.org/). Only useful for kernel devs
2491 running the KUnit test harness, and not intended for inclusion into a
2494 For more information on KUnit and unit tests in general please refer
2495 to the KUnit documentation in Documentation/dev-tools/kunit/.
2499 config LINEAR_RANGES_TEST
2500 tristate "KUnit test for linear_ranges"
2502 select LINEAR_RANGES
2504 This builds the linear_ranges unit test, which runs on boot.
2505 Tests the linear_ranges logic correctness.
2506 For more information on KUnit and unit tests in general please refer
2507 to the KUnit documentation in Documentation/dev-tools/kunit/.
2511 config CMDLINE_KUNIT_TEST
2512 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2514 default KUNIT_ALL_TESTS
2516 This builds the cmdline API unit test.
2517 Tests the logic of API provided by cmdline.c.
2518 For more information on KUnit and unit tests in general please refer
2519 to the KUnit documentation in Documentation/dev-tools/kunit/.
2524 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2526 default KUNIT_ALL_TESTS
2528 This builds the bits unit test.
2529 Tests the logic of macros defined in bits.h.
2530 For more information on KUnit and unit tests in general please refer
2531 to the KUnit documentation in Documentation/dev-tools/kunit/.
2535 config SLUB_KUNIT_TEST
2536 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2537 depends on SLUB_DEBUG && KUNIT
2538 default KUNIT_ALL_TESTS
2540 This builds SLUB allocator unit test.
2541 Tests SLUB cache debugging functionality.
2542 For more information on KUnit and unit tests in general please refer
2543 to the KUnit documentation in Documentation/dev-tools/kunit/.
2547 config RATIONAL_KUNIT_TEST
2548 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2549 depends on KUNIT && RATIONAL
2550 default KUNIT_ALL_TESTS
2552 This builds the rational math unit test.
2553 For more information on KUnit and unit tests in general please refer
2554 to the KUnit documentation in Documentation/dev-tools/kunit/.
2558 config MEMCPY_KUNIT_TEST
2559 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2561 default KUNIT_ALL_TESTS
2563 Builds unit tests for memcpy(), memmove(), and memset() functions.
2564 For more information on KUnit and unit tests in general please refer
2565 to the KUnit documentation in Documentation/dev-tools/kunit/.
2569 config IS_SIGNED_TYPE_KUNIT_TEST
2570 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2572 default KUNIT_ALL_TESTS
2574 Builds unit tests for the is_signed_type() macro.
2576 For more information on KUnit and unit tests in general please refer
2577 to the KUnit documentation in Documentation/dev-tools/kunit/.
2581 config OVERFLOW_KUNIT_TEST
2582 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2584 default KUNIT_ALL_TESTS
2586 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2589 For more information on KUnit and unit tests in general please refer
2590 to the KUnit documentation in Documentation/dev-tools/kunit/.
2594 config STACKINIT_KUNIT_TEST
2595 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2597 default KUNIT_ALL_TESTS
2599 Test if the kernel is zero-initializing stack variables and
2600 padding. Coverage is controlled by compiler flags,
2601 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2602 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2603 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2605 config FORTIFY_KUNIT_TEST
2606 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2607 depends on KUNIT && FORTIFY_SOURCE
2608 default KUNIT_ALL_TESTS
2610 Builds unit tests for checking internals of FORTIFY_SOURCE as used
2611 by the str*() and mem*() family of functions. For testing runtime
2612 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2614 config HW_BREAKPOINT_KUNIT_TEST
2615 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2616 depends on HAVE_HW_BREAKPOINT
2618 default KUNIT_ALL_TESTS
2620 Tests for hw_breakpoint constraints accounting.
2624 config STRSCPY_KUNIT_TEST
2625 tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS
2627 default KUNIT_ALL_TESTS
2629 config SIPHASH_KUNIT_TEST
2630 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2632 default KUNIT_ALL_TESTS
2634 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2635 functions on boot (or module load).
2637 This is intended to help people writing architecture-specific
2638 optimized versions. If unsure, say N.
2641 tristate "udelay test driver"
2643 This builds the "udelay_test" module that helps to make sure
2644 that udelay() is working properly.
2648 config TEST_STATIC_KEYS
2649 tristate "Test static keys"
2652 Test the static key interfaces.
2656 config TEST_DYNAMIC_DEBUG
2657 tristate "Test DYNAMIC_DEBUG"
2658 depends on DYNAMIC_DEBUG
2660 This module registers a tracer callback to count enabled
2661 pr_debugs in a 'do_debugging' function, then alters their
2662 enablements, calls the function, and compares counts.
2667 tristate "kmod stress tester"
2669 depends on NETDEVICES && NET_CORE && INET # for TUN
2671 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2677 Test the kernel's module loading mechanism: kmod. kmod implements
2678 support to load modules using the Linux kernel's usermode helper.
2679 This test provides a series of tests against kmod.
2681 Although technically you can either build test_kmod as a module or
2682 into the kernel we disallow building it into the kernel since
2683 it stress tests request_module() and this will very likely cause
2684 some issues by taking over precious threads available from other
2685 module load requests, ultimately this could be fatal.
2689 tools/testing/selftests/kmod/kmod.sh --help
2693 config TEST_DEBUG_VIRTUAL
2694 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2695 depends on DEBUG_VIRTUAL
2697 Test the kernel's ability to detect incorrect calls to
2698 virt_to_phys() done against the non-linear part of the
2699 kernel's virtual address map.
2703 config TEST_MEMCAT_P
2704 tristate "Test memcat_p() helper function"
2706 Test the memcat_p() helper for correctly merging two
2707 pointer arrays together.
2711 config TEST_LIVEPATCH
2712 tristate "Test livepatching"
2714 depends on DYNAMIC_DEBUG
2715 depends on LIVEPATCH
2718 Test kernel livepatching features for correctness. The tests will
2719 load test modules that will be livepatched in various scenarios.
2721 To run all the livepatching tests:
2723 make -C tools/testing/selftests TARGETS=livepatch run_tests
2725 Alternatively, individual tests may be invoked:
2727 tools/testing/selftests/livepatch/test-callbacks.sh
2728 tools/testing/selftests/livepatch/test-livepatch.sh
2729 tools/testing/selftests/livepatch/test-shadow-vars.sh
2734 tristate "Perform selftest on object aggreration manager"
2738 Enable this option to test object aggregation manager on boot
2742 tristate "Test heap/page initialization"
2744 Test if the kernel is zero-initializing heap and page allocations.
2745 This can be useful to test init_on_alloc and init_on_free features.
2750 tristate "Test HMM (Heterogeneous Memory Management)"
2751 depends on TRANSPARENT_HUGEPAGE
2752 depends on DEVICE_PRIVATE
2756 This is a pseudo device driver solely for testing HMM.
2757 Say M here if you want to build the HMM test module.
2758 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2762 config TEST_FREE_PAGES
2763 tristate "Test freeing pages"
2765 Test that a memory leak does not occur due to a race between
2766 freeing a block of pages and a speculative page reference.
2767 Loading this module is safe if your kernel has the bug fixed.
2768 If the bug is not fixed, it will leak gigabytes of memory and
2769 probably OOM your system.
2772 tristate "Test floating point operations in kernel space"
2773 depends on X86 && !KCOV_INSTRUMENT_ALL
2775 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2776 which will trigger a sequence of floating point operations. This is used
2777 for self-testing floating point control register setting in
2782 config TEST_CLOCKSOURCE_WATCHDOG
2783 tristate "Test clocksource watchdog in kernel space"
2784 depends on CLOCKSOURCE_WATCHDOG
2786 Enable this option to create a kernel module that will trigger
2787 a test of the clocksource watchdog. This module may be loaded
2788 via modprobe or insmod in which case it will run upon being
2789 loaded, or it may be built in, in which case it will run
2794 endif # RUNTIME_TESTING_MENU
2796 config ARCH_USE_MEMTEST
2799 An architecture should select this when it uses early_memtest()
2800 during boot process.
2804 depends on ARCH_USE_MEMTEST
2806 This option adds a kernel parameter 'memtest', which allows memtest
2807 to be set and executed.
2808 memtest=0, mean disabled; -- default
2809 memtest=1, mean do 1 test pattern;
2811 memtest=17, mean do 17 test patterns.
2812 If you are unsure how to answer this question, answer N.
2816 config HYPERV_TESTING
2817 bool "Microsoft Hyper-V driver testing"
2819 depends on HYPERV && DEBUG_FS
2821 Select this option to enable Hyper-V vmbus testing.
2823 endmenu # "Kernel Testing and Coverage"
2827 config RUST_DEBUG_ASSERTIONS
2828 bool "Debug assertions"
2831 Enables rustc's `-Cdebug-assertions` codegen option.
2833 This flag lets you turn `cfg(debug_assertions)` conditional
2834 compilation on or off. This can be used to enable extra debugging
2835 code in development but not in production. For example, it controls
2836 the behavior of the standard library's `debug_assert!` macro.
2838 Note that this will apply to all Rust code, including `core`.
2842 config RUST_OVERFLOW_CHECKS
2843 bool "Overflow checks"
2847 Enables rustc's `-Coverflow-checks` codegen option.
2849 This flag allows you to control the behavior of runtime integer
2850 overflow. When overflow-checks are enabled, a Rust panic will occur
2853 Note that this will apply to all Rust code, including `core`.
2857 config RUST_BUILD_ASSERT_ALLOW
2858 bool "Allow unoptimized build-time assertions"
2861 Controls how are `build_error!` and `build_assert!` handled during build.
2863 If calls to them exist in the binary, it may indicate a violated invariant
2864 or that the optimizer failed to verify the invariant during compilation.
2866 This should not happen, thus by default the build is aborted. However,
2867 as an escape hatch, you can choose Y here to ignore them during build
2868 and let the check be carried at runtime (with `panic!` being called if
2875 source "Documentation/Kconfig"
2877 endmenu # Kernel hacking
projects / linux-2.6-block.git / blob