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.
235 prompt "Debug information"
236 depends on DEBUG_KERNEL
238 Selecting something other than "None" results in a kernel image
239 that will include debugging info resulting in a larger kernel image.
240 This adds debug symbols to the kernel and modules (gcc -g), and
241 is needed if you intend to use kernel crashdump or binary object
242 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
244 Choose which version of DWARF debug info to emit. If unsure,
245 select "Toolchain default".
247 config DEBUG_INFO_NONE
248 bool "Disable debug information"
250 Do not build the kernel with debugging information, which will
251 result in a faster and smaller build.
253 config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
254 bool "Rely on the toolchain's implicit default DWARF version"
257 The implicit default version of DWARF debug info produced by a
258 toolchain changes over time.
260 This can break consumers of the debug info that haven't upgraded to
261 support newer revisions, and prevent testing newer versions, but
262 those should be less common scenarios.
264 config DEBUG_INFO_DWARF4
265 bool "Generate DWARF Version 4 debuginfo"
268 Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+.
270 If you have consumers of DWARF debug info that are not ready for
271 newer revisions of DWARF, you may wish to choose this or have your
274 config DEBUG_INFO_DWARF5
275 bool "Generate DWARF Version 5 debuginfo"
277 depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)))
279 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
280 5.0+ accepts the -gdwarf-5 flag but only had partial support for some
281 draft features until 7.0), and gdb 8.0+.
283 Changes to the structure of debug info in Version 5 allow for around
284 15-18% savings in resulting image and debug info section sizes as
285 compared to DWARF Version 4. DWARF Version 5 standardizes previous
286 extensions such as accelerators for symbol indexing and the format
287 for fission (.dwo/.dwp) files. Users may not want to select this
288 config if they rely on tooling that has not yet been updated to
289 support DWARF Version 5.
291 endchoice # "Debug information"
295 config DEBUG_INFO_REDUCED
296 bool "Reduce debugging information"
298 If you say Y here gcc is instructed to generate less debugging
299 information for structure types. This means that tools that
300 need full debugging information (like kgdb or systemtap) won't
301 be happy. But if you merely need debugging information to
302 resolve line numbers there is no loss. Advantage is that
303 build directory object sizes shrink dramatically over a full
304 DEBUG_INFO build and compile times are reduced too.
305 Only works with newer gcc versions.
307 config DEBUG_INFO_COMPRESSED
308 bool "Compressed debugging information"
309 depends on $(cc-option,-gz=zlib)
310 depends on $(ld-option,--compress-debug-sections=zlib)
312 Compress the debug information using zlib. Requires GCC 5.0+ or Clang
313 5.0+, binutils 2.26+, and zlib.
315 Users of dpkg-deb via scripts/package/builddeb may find an increase in
316 size of their debug .deb packages with this config set, due to the
317 debug info being compressed with zlib, then the object files being
318 recompressed with a different compression scheme. But this is still
319 preferable to setting $KDEB_COMPRESS to "none" which would be even
322 config DEBUG_INFO_SPLIT
323 bool "Produce split debuginfo in .dwo files"
324 depends on $(cc-option,-gsplit-dwarf)
326 Generate debug info into separate .dwo files. This significantly
327 reduces the build directory size for builds with DEBUG_INFO,
328 because it stores the information only once on disk in .dwo
329 files instead of multiple times in object files and executables.
330 In addition the debug information is also compressed.
332 Requires recent gcc (4.7+) and recent gdb/binutils.
333 Any tool that packages or reads debug information would need
334 to know about the .dwo files and include them.
335 Incompatible with older versions of ccache.
337 config DEBUG_INFO_BTF
338 bool "Generate BTF typeinfo"
339 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
340 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
341 depends on BPF_SYSCALL
342 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121
344 Generate deduplicated BTF type information from DWARF debug info.
345 Turning this on expects presence of pahole tool, which will convert
346 DWARF type info into equivalent deduplicated BTF type info.
348 config PAHOLE_HAS_SPLIT_BTF
349 def_bool PAHOLE_VERSION >= 119
351 config PAHOLE_HAS_BTF_TAG
352 def_bool PAHOLE_VERSION >= 123
353 depends on CC_IS_CLANG
355 Decide whether pahole emits btf_tag attributes (btf_type_tag and
356 btf_decl_tag) or not. Currently only clang compiler implements
357 these attributes, so make the config depend on CC_IS_CLANG.
359 config DEBUG_INFO_BTF_MODULES
361 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
363 Generate compact split BTF type information for kernel modules.
365 config MODULE_ALLOW_BTF_MISMATCH
366 bool "Allow loading modules with non-matching BTF type info"
367 depends on DEBUG_INFO_BTF_MODULES
369 For modules whose split BTF does not match vmlinux, load without
370 BTF rather than refusing to load. The default behavior with
371 module BTF enabled is to reject modules with such mismatches;
372 this option will still load module BTF where possible but ignore
373 it when a mismatch is found.
376 bool "Provide GDB scripts for kernel debugging"
378 This creates the required links to GDB helper scripts in the
379 build directory. If you load vmlinux into gdb, the helper
380 scripts will be automatically imported by gdb as well, and
381 additional functions are available to analyze a Linux kernel
382 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
388 int "Warn for stack frames larger than"
390 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
391 default 2048 if PARISC
392 default 1536 if (!64BIT && XTENSA)
393 default 1024 if !64BIT
394 default 2048 if 64BIT
396 Tell gcc to warn at build time for stack frames larger than this.
397 Setting this too low will cause a lot of warnings.
398 Setting it to 0 disables the warning.
400 config STRIP_ASM_SYMS
401 bool "Strip assembler-generated symbols during link"
404 Strip internal assembler-generated symbols during a link (symbols
405 that look like '.Lxxx') so they don't pollute the output of
406 get_wchan() and suchlike.
409 bool "Generate readable assembler code"
410 depends on DEBUG_KERNEL
413 Disable some compiler optimizations that tend to generate human unreadable
414 assembler output. This may make the kernel slightly slower, but it helps
415 to keep kernel developers who have to stare a lot at assembler listings
418 config HEADERS_INSTALL
419 bool "Install uapi headers to usr/include"
422 This option will install uapi headers (headers exported to user-space)
423 into the usr/include directory for use during the kernel build.
424 This is unneeded for building the kernel itself, but needed for some
425 user-space program samples. It is also needed by some features such
426 as uapi header sanity checks.
428 config DEBUG_SECTION_MISMATCH
429 bool "Enable full Section mismatch analysis"
432 The section mismatch analysis checks if there are illegal
433 references from one section to another section.
434 During linktime or runtime, some sections are dropped;
435 any use of code/data previously in these sections would
436 most likely result in an oops.
437 In the code, functions and variables are annotated with
438 __init,, etc. (see the full list in include/linux/init.h),
439 which results in the code/data being placed in specific sections.
440 The section mismatch analysis is always performed after a full
441 kernel build, and enabling this option causes the following
442 additional step to occur:
443 - Add the option -fno-inline-functions-called-once to gcc commands.
444 When inlining a function annotated with __init in a non-init
445 function, we would lose the section information and thus
446 the analysis would not catch the illegal reference.
447 This option tells gcc to inline less (but it does result in
450 config SECTION_MISMATCH_WARN_ONLY
451 bool "Make section mismatch errors non-fatal"
454 If you say N here, the build process will fail if there are any
455 section mismatch, instead of just throwing warnings.
459 config DEBUG_FORCE_FUNCTION_ALIGN_64B
460 bool "Force all function address 64B aligned"
461 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC)
463 There are cases that a commit from one domain changes the function
464 address alignment of other domains, and cause magic performance
465 bump (regression or improvement). Enable this option will help to
466 verify if the bump is caused by function alignment changes, while
467 it will slightly increase the kernel size and affect icache usage.
469 It is mainly for debug and performance tuning use.
472 # Select this config option from the architecture Kconfig, if it
473 # is preferred to always offer frame pointers as a config
474 # option on the architecture (regardless of KERNEL_DEBUG):
476 config ARCH_WANT_FRAME_POINTERS
480 bool "Compile the kernel with frame pointers"
481 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
482 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
484 If you say Y here the resulting kernel image will be slightly
485 larger and slower, but it gives very useful debugging information
486 in case of kernel bugs. (precise oopses/stacktraces/warnings)
491 config STACK_VALIDATION
492 bool "Compile-time stack metadata validation"
493 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
497 Validate frame pointer rules at compile-time. This helps ensure that
498 runtime stack traces are more reliable.
500 For more information, see
501 tools/objtool/Documentation/stack-validation.txt.
503 config NOINSTR_VALIDATION
505 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
510 bool "Generate vmlinux.map file when linking"
513 Selecting this option will pass "-Map=vmlinux.map" to ld
514 when linking vmlinux. That file can be useful for verifying
515 and debugging magic section games, and for seeing which
516 pieces of code get eliminated with
517 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
519 config DEBUG_FORCE_WEAK_PER_CPU
520 bool "Force weak per-cpu definitions"
521 depends on DEBUG_KERNEL
523 s390 and alpha require percpu variables in modules to be
524 defined weak to work around addressing range issue which
525 puts the following two restrictions on percpu variable
528 1. percpu symbols must be unique whether static or not
529 2. percpu variables can't be defined inside a function
531 To ensure that generic code follows the above rules, this
532 option forces all percpu variables to be defined as weak.
534 endmenu # "Compiler options"
536 menu "Generic Kernel Debugging Instruments"
539 bool "Magic SysRq key"
542 If you say Y here, you will have some control over the system even
543 if the system crashes for example during kernel debugging (e.g., you
544 will be able to flush the buffer cache to disk, reboot the system
545 immediately or dump some status information). This is accomplished
546 by pressing various keys while holding SysRq (Alt+PrintScreen). It
547 also works on a serial console (on PC hardware at least), if you
548 send a BREAK and then within 5 seconds a command keypress. The
549 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
550 Don't say Y unless you really know what this hack does.
552 config MAGIC_SYSRQ_DEFAULT_ENABLE
553 hex "Enable magic SysRq key functions by default"
554 depends on MAGIC_SYSRQ
557 Specifies which SysRq key functions are enabled by default.
558 This may be set to 1 or 0 to enable or disable them all, or
559 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
561 config MAGIC_SYSRQ_SERIAL
562 bool "Enable magic SysRq key over serial"
563 depends on MAGIC_SYSRQ
566 Many embedded boards have a disconnected TTL level serial which can
567 generate some garbage that can lead to spurious false sysrq detects.
568 This option allows you to decide whether you want to enable the
571 config MAGIC_SYSRQ_SERIAL_SEQUENCE
572 string "Char sequence that enables magic SysRq over serial"
573 depends on MAGIC_SYSRQ_SERIAL
576 Specifies a sequence of characters that can follow BREAK to enable
577 SysRq on a serial console.
579 If unsure, leave an empty string and the option will not be enabled.
582 bool "Debug Filesystem"
584 debugfs is a virtual file system that kernel developers use to put
585 debugging files into. Enable this option to be able to read and
586 write to these files.
588 For detailed documentation on the debugfs API, see
589 Documentation/filesystems/.
594 prompt "Debugfs default access"
596 default DEBUG_FS_ALLOW_ALL
598 This selects the default access restrictions for debugfs.
599 It can be overridden with kernel command line option
600 debugfs=[on,no-mount,off]. The restrictions apply for API access
601 and filesystem registration.
603 config DEBUG_FS_ALLOW_ALL
606 No restrictions apply. Both API and filesystem registration
607 is on. This is the normal default operation.
609 config DEBUG_FS_DISALLOW_MOUNT
610 bool "Do not register debugfs as filesystem"
612 The API is open but filesystem is not loaded. Clients can still do
613 their work and read with debug tools that do not need
616 config DEBUG_FS_ALLOW_NONE
619 Access is off. Clients get -PERM when trying to create nodes in
620 debugfs tree and debugfs is not registered as a filesystem.
621 Client can then back-off or continue without debugfs access.
625 source "lib/Kconfig.kgdb"
626 source "lib/Kconfig.ubsan"
627 source "lib/Kconfig.kcsan"
631 menu "Networking Debugging"
633 source "net/Kconfig.debug"
635 endmenu # "Networking Debugging"
637 menu "Memory Debugging"
639 source "mm/Kconfig.debug"
642 bool "Debug object operations"
643 depends on DEBUG_KERNEL
645 If you say Y here, additional code will be inserted into the
646 kernel to track the life time of various objects and validate
647 the operations on those objects.
649 config DEBUG_OBJECTS_SELFTEST
650 bool "Debug objects selftest"
651 depends on DEBUG_OBJECTS
653 This enables the selftest of the object debug code.
655 config DEBUG_OBJECTS_FREE
656 bool "Debug objects in freed memory"
657 depends on DEBUG_OBJECTS
659 This enables checks whether a k/v free operation frees an area
660 which contains an object which has not been deactivated
661 properly. This can make kmalloc/kfree-intensive workloads
664 config DEBUG_OBJECTS_TIMERS
665 bool "Debug timer objects"
666 depends on DEBUG_OBJECTS
668 If you say Y here, additional code will be inserted into the
669 timer routines to track the life time of timer objects and
670 validate the timer operations.
672 config DEBUG_OBJECTS_WORK
673 bool "Debug work objects"
674 depends on DEBUG_OBJECTS
676 If you say Y here, additional code will be inserted into the
677 work queue routines to track the life time of work objects and
678 validate the work operations.
680 config DEBUG_OBJECTS_RCU_HEAD
681 bool "Debug RCU callbacks objects"
682 depends on DEBUG_OBJECTS
684 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
686 config DEBUG_OBJECTS_PERCPU_COUNTER
687 bool "Debug percpu counter objects"
688 depends on DEBUG_OBJECTS
690 If you say Y here, additional code will be inserted into the
691 percpu counter routines to track the life time of percpu counter
692 objects and validate the percpu counter operations.
694 config DEBUG_OBJECTS_ENABLE_DEFAULT
695 int "debug_objects bootup default value (0-1)"
698 depends on DEBUG_OBJECTS
700 Debug objects boot parameter default value
703 bool "Debug slab memory allocations"
704 depends on DEBUG_KERNEL && SLAB
706 Say Y here to have the kernel do limited verification on memory
707 allocation as well as poisoning memory on free to catch use of freed
708 memory. This can make kmalloc/kfree-intensive workloads much slower.
711 bool "SLUB debugging on by default"
712 depends on SLUB && SLUB_DEBUG
713 select STACKDEPOT_ALWAYS_INIT if STACKTRACE_SUPPORT
716 Boot with debugging on by default. SLUB boots by default with
717 the runtime debug capabilities switched off. Enabling this is
718 equivalent to specifying the "slub_debug" parameter on boot.
719 There is no support for more fine grained debug control like
720 possible with slub_debug=xxx. SLUB debugging may be switched
721 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
726 bool "Enable SLUB performance statistics"
727 depends on SLUB && SYSFS
729 SLUB statistics are useful to debug SLUBs allocation behavior in
730 order find ways to optimize the allocator. This should never be
731 enabled for production use since keeping statistics slows down
732 the allocator by a few percentage points. The slabinfo command
733 supports the determination of the most active slabs to figure
734 out which slabs are relevant to a particular load.
735 Try running: slabinfo -DA
737 config HAVE_DEBUG_KMEMLEAK
740 config DEBUG_KMEMLEAK
741 bool "Kernel memory leak detector"
742 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
744 select STACKTRACE if STACKTRACE_SUPPORT
748 Say Y here if you want to enable the memory leak
749 detector. The memory allocation/freeing is traced in a way
750 similar to the Boehm's conservative garbage collector, the
751 difference being that the orphan objects are not freed but
752 only shown in /sys/kernel/debug/kmemleak. Enabling this
753 feature will introduce an overhead to memory
754 allocations. See Documentation/dev-tools/kmemleak.rst for more
757 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
758 of finding leaks due to the slab objects poisoning.
760 In order to access the kmemleak file, debugfs needs to be
761 mounted (usually at /sys/kernel/debug).
763 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
764 int "Kmemleak memory pool size"
765 depends on DEBUG_KMEMLEAK
769 Kmemleak must track all the memory allocations to avoid
770 reporting false positives. Since memory may be allocated or
771 freed before kmemleak is fully initialised, use a static pool
772 of metadata objects to track such callbacks. After kmemleak is
773 fully initialised, this memory pool acts as an emergency one
774 if slab allocations fail.
776 config DEBUG_KMEMLEAK_TEST
777 tristate "Simple test for the kernel memory leak detector"
778 depends on DEBUG_KMEMLEAK && m
780 This option enables a module that explicitly leaks memory.
784 config DEBUG_KMEMLEAK_DEFAULT_OFF
785 bool "Default kmemleak to off"
786 depends on DEBUG_KMEMLEAK
788 Say Y here to disable kmemleak by default. It can then be enabled
789 on the command line via kmemleak=on.
791 config DEBUG_KMEMLEAK_AUTO_SCAN
792 bool "Enable kmemleak auto scan thread on boot up"
794 depends on DEBUG_KMEMLEAK
796 Depending on the cpu, kmemleak scan may be cpu intensive and can
797 stall user tasks at times. This option enables/disables automatic
798 kmemleak scan at boot up.
800 Say N here to disable kmemleak auto scan thread to stop automatic
801 scanning. Disabling this option disables automatic reporting of
806 config DEBUG_STACK_USAGE
807 bool "Stack utilization instrumentation"
808 depends on DEBUG_KERNEL && !IA64
810 Enables the display of the minimum amount of free stack which each
811 task has ever had available in the sysrq-T and sysrq-P debug output.
813 This option will slow down process creation somewhat.
815 config SCHED_STACK_END_CHECK
816 bool "Detect stack corruption on calls to schedule()"
817 depends on DEBUG_KERNEL
820 This option checks for a stack overrun on calls to schedule().
821 If the stack end location is found to be over written always panic as
822 the content of the corrupted region can no longer be trusted.
823 This is to ensure no erroneous behaviour occurs which could result in
824 data corruption or a sporadic crash at a later stage once the region
825 is examined. The runtime overhead introduced is minimal.
827 config ARCH_HAS_DEBUG_VM_PGTABLE
830 An architecture should select this when it can successfully
831 build and run DEBUG_VM_PGTABLE.
835 depends on DEBUG_KERNEL
837 Enable this to turn on extended checks in the virtual-memory system
838 that may impact performance.
842 config DEBUG_VM_VMACACHE
843 bool "Debug VMA caching"
846 Enable this to turn on VMA caching debug information. Doing so
847 can cause significant overhead, so only enable it in non-production
853 bool "Debug VM red-black trees"
856 Enable VM red-black tree debugging information and extra validations.
860 config DEBUG_VM_PGFLAGS
861 bool "Debug page-flags operations"
864 Enables extra validation on page flags operations.
868 config DEBUG_VM_PGTABLE
869 bool "Debug arch page table for semantics compliance"
871 depends on ARCH_HAS_DEBUG_VM_PGTABLE
872 default y if DEBUG_VM
874 This option provides a debug method which can be used to test
875 architecture page table helper functions on various platforms in
876 verifying if they comply with expected generic MM semantics. This
877 will help architecture code in making sure that any changes or
878 new additions of these helpers still conform to expected
879 semantics of the generic MM. Platforms will have to opt in for
880 this through ARCH_HAS_DEBUG_VM_PGTABLE.
884 config ARCH_HAS_DEBUG_VIRTUAL
888 bool "Debug VM translations"
889 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
891 Enable some costly sanity checks in virtual to page code. This can
892 catch mistakes with virt_to_page() and friends.
896 config DEBUG_NOMMU_REGIONS
897 bool "Debug the global anon/private NOMMU mapping region tree"
898 depends on DEBUG_KERNEL && !MMU
900 This option causes the global tree of anonymous and private mapping
901 regions to be regularly checked for invalid topology.
903 config DEBUG_MEMORY_INIT
904 bool "Debug memory initialisation" if EXPERT
907 Enable this for additional checks during memory initialisation.
908 The sanity checks verify aspects of the VM such as the memory model
909 and other information provided by the architecture. Verbose
910 information will be printed at KERN_DEBUG loglevel depending
911 on the mminit_loglevel= command-line option.
915 config MEMORY_NOTIFIER_ERROR_INJECT
916 tristate "Memory hotplug notifier error injection module"
917 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
919 This option provides the ability to inject artificial errors to
920 memory hotplug notifier chain callbacks. It is controlled through
921 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
923 If the notifier call chain should be failed with some events
924 notified, write the error code to "actions/<notifier event>/error".
926 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
928 # cd /sys/kernel/debug/notifier-error-inject/memory
929 # echo -12 > actions/MEM_GOING_OFFLINE/error
930 # echo offline > /sys/devices/system/memory/memoryXXX/state
931 bash: echo: write error: Cannot allocate memory
933 To compile this code as a module, choose M here: the module will
934 be called memory-notifier-error-inject.
938 config DEBUG_PER_CPU_MAPS
939 bool "Debug access to per_cpu maps"
940 depends on DEBUG_KERNEL
943 Say Y to verify that the per_cpu map being accessed has
944 been set up. This adds a fair amount of code to kernel memory
945 and decreases performance.
949 config DEBUG_KMAP_LOCAL
950 bool "Debug kmap_local temporary mappings"
951 depends on DEBUG_KERNEL && KMAP_LOCAL
953 This option enables additional error checking for the kmap_local
954 infrastructure. Disable for production use.
956 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
959 config DEBUG_KMAP_LOCAL_FORCE_MAP
960 bool "Enforce kmap_local temporary mappings"
961 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
963 select DEBUG_KMAP_LOCAL
965 This option enforces temporary mappings through the kmap_local
966 mechanism for non-highmem pages and on non-highmem systems.
967 Disable this for production systems!
970 bool "Highmem debugging"
971 depends on DEBUG_KERNEL && HIGHMEM
972 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
973 select DEBUG_KMAP_LOCAL
975 This option enables additional error checking for high memory
976 systems. Disable for production systems.
978 config HAVE_DEBUG_STACKOVERFLOW
981 config DEBUG_STACKOVERFLOW
982 bool "Check for stack overflows"
983 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
985 Say Y here if you want to check for overflows of kernel, IRQ
986 and exception stacks (if your architecture uses them). This
987 option will show detailed messages if free stack space drops
988 below a certain limit.
990 These kinds of bugs usually occur when call-chains in the
991 kernel get too deep, especially when interrupts are
994 Use this in cases where you see apparently random memory
995 corruption, especially if it appears in 'struct thread_info'
997 If in doubt, say "N".
999 source "lib/Kconfig.kasan"
1000 source "lib/Kconfig.kfence"
1002 endmenu # "Memory Debugging"
1005 bool "Debug shared IRQ handlers"
1006 depends on DEBUG_KERNEL
1008 Enable this to generate a spurious interrupt just before a shared
1009 interrupt handler is deregistered (generating one when registering
1010 is currently disabled). Drivers need to handle this correctly. Some
1011 don't and need to be caught.
1013 menu "Debug Oops, Lockups and Hangs"
1015 config PANIC_ON_OOPS
1016 bool "Panic on Oops"
1018 Say Y here to enable the kernel to panic when it oopses. This
1019 has the same effect as setting oops=panic on the kernel command
1022 This feature is useful to ensure that the kernel does not do
1023 anything erroneous after an oops which could result in data
1024 corruption or other issues.
1028 config PANIC_ON_OOPS_VALUE
1031 default 0 if !PANIC_ON_OOPS
1032 default 1 if PANIC_ON_OOPS
1034 config PANIC_TIMEOUT
1038 Set the timeout value (in seconds) until a reboot occurs when
1039 the kernel panics. If n = 0, then we wait forever. A timeout
1040 value n > 0 will wait n seconds before rebooting, while a timeout
1041 value n < 0 will reboot immediately.
1043 config LOCKUP_DETECTOR
1046 config SOFTLOCKUP_DETECTOR
1047 bool "Detect Soft Lockups"
1048 depends on DEBUG_KERNEL && !S390
1049 select LOCKUP_DETECTOR
1051 Say Y here to enable the kernel to act as a watchdog to detect
1054 Softlockups are bugs that cause the kernel to loop in kernel
1055 mode for more than 20 seconds, without giving other tasks a
1056 chance to run. The current stack trace is displayed upon
1057 detection and the system will stay locked up.
1059 config BOOTPARAM_SOFTLOCKUP_PANIC
1060 bool "Panic (Reboot) On Soft Lockups"
1061 depends on SOFTLOCKUP_DETECTOR
1063 Say Y here to enable the kernel to panic on "soft lockups",
1064 which are bugs that cause the kernel to loop in kernel
1065 mode for more than 20 seconds (configurable using the watchdog_thresh
1066 sysctl), without giving other tasks a chance to run.
1068 The panic can be used in combination with panic_timeout,
1069 to cause the system to reboot automatically after a
1070 lockup has been detected. This feature is useful for
1071 high-availability systems that have uptime guarantees and
1072 where a lockup must be resolved ASAP.
1076 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
1078 depends on SOFTLOCKUP_DETECTOR
1080 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
1081 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
1083 config HARDLOCKUP_DETECTOR_PERF
1085 select SOFTLOCKUP_DETECTOR
1088 # Enables a timestamp based low pass filter to compensate for perf based
1089 # hard lockup detection which runs too fast due to turbo modes.
1091 config HARDLOCKUP_CHECK_TIMESTAMP
1095 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1096 # lockup detector rather than the perf based detector.
1098 config HARDLOCKUP_DETECTOR
1099 bool "Detect Hard Lockups"
1100 depends on DEBUG_KERNEL && !S390
1101 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1102 select LOCKUP_DETECTOR
1103 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1105 Say Y here to enable the kernel to act as a watchdog to detect
1108 Hardlockups are bugs that cause the CPU to loop in kernel mode
1109 for more than 10 seconds, without letting other interrupts have a
1110 chance to run. The current stack trace is displayed upon detection
1111 and the system will stay locked up.
1113 config BOOTPARAM_HARDLOCKUP_PANIC
1114 bool "Panic (Reboot) On Hard Lockups"
1115 depends on HARDLOCKUP_DETECTOR
1117 Say Y here to enable the kernel to panic on "hard lockups",
1118 which are bugs that cause the kernel to loop in kernel
1119 mode with interrupts disabled for more than 10 seconds (configurable
1120 using the watchdog_thresh sysctl).
1124 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
1126 depends on HARDLOCKUP_DETECTOR
1128 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
1129 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
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.
1178 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
1180 depends on DETECT_HUNG_TASK
1182 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
1183 default 1 if BOOTPARAM_HUNG_TASK_PANIC
1186 bool "Detect Workqueue Stalls"
1187 depends on DEBUG_KERNEL
1189 Say Y here to enable stall detection on workqueues. If a
1190 worker pool doesn't make forward progress on a pending work
1191 item for over a given amount of time, 30s by default, a
1192 warning message is printed along with dump of workqueue
1193 state. This can be configured through kernel parameter
1194 "workqueue.watchdog_thresh" and its sysfs counterpart.
1197 tristate "Test module to generate lockups"
1200 This builds the "test_lockup" module that helps to make sure
1201 that watchdogs and lockup detectors are working properly.
1203 Depending on module parameters it could emulate soft or hard
1204 lockup, "hung task", or locking arbitrary lock for a long time.
1205 Also it could generate series of lockups with cooling-down periods.
1209 endmenu # "Debug lockups and hangs"
1211 menu "Scheduler Debugging"
1214 bool "Collect scheduler debugging info"
1215 depends on DEBUG_KERNEL && PROC_FS
1218 If you say Y here, the /proc/sched_debug file will be provided
1219 that can help debug the scheduler. The runtime overhead of this
1227 bool "Collect scheduler statistics"
1228 depends on DEBUG_KERNEL && PROC_FS
1231 If you say Y here, additional code will be inserted into the
1232 scheduler and related routines to collect statistics about
1233 scheduler behavior and provide them in /proc/schedstat. These
1234 stats may be useful for both tuning and debugging the scheduler
1235 If you aren't debugging the scheduler or trying to tune a specific
1236 application, you can say N to avoid the very slight overhead
1241 config DEBUG_TIMEKEEPING
1242 bool "Enable extra timekeeping sanity checking"
1244 This option will enable additional timekeeping sanity checks
1245 which may be helpful when diagnosing issues where timekeeping
1246 problems are suspected.
1248 This may include checks in the timekeeping hotpaths, so this
1249 option may have a (very small) performance impact to some
1254 config DEBUG_PREEMPT
1255 bool "Debug preemptible kernel"
1256 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1259 If you say Y here then the kernel will use a debug variant of the
1260 commonly used smp_processor_id() function and will print warnings
1261 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1262 will detect preemption count underflows.
1264 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1266 config LOCK_DEBUGGING_SUPPORT
1268 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1271 config PROVE_LOCKING
1272 bool "Lock debugging: prove locking correctness"
1273 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1275 select DEBUG_SPINLOCK
1276 select DEBUG_MUTEXES if !PREEMPT_RT
1277 select DEBUG_RT_MUTEXES if RT_MUTEXES
1279 select DEBUG_WW_MUTEX_SLOWPATH
1280 select DEBUG_LOCK_ALLOC
1281 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1282 select TRACE_IRQFLAGS
1285 This feature enables the kernel to prove that all locking
1286 that occurs in the kernel runtime is mathematically
1287 correct: that under no circumstance could an arbitrary (and
1288 not yet triggered) combination of observed locking
1289 sequences (on an arbitrary number of CPUs, running an
1290 arbitrary number of tasks and interrupt contexts) cause a
1293 In short, this feature enables the kernel to report locking
1294 related deadlocks before they actually occur.
1296 The proof does not depend on how hard and complex a
1297 deadlock scenario would be to trigger: how many
1298 participant CPUs, tasks and irq-contexts would be needed
1299 for it to trigger. The proof also does not depend on
1300 timing: if a race and a resulting deadlock is possible
1301 theoretically (no matter how unlikely the race scenario
1302 is), it will be proven so and will immediately be
1303 reported by the kernel (once the event is observed that
1304 makes the deadlock theoretically possible).
1306 If a deadlock is impossible (i.e. the locking rules, as
1307 observed by the kernel, are mathematically correct), the
1308 kernel reports nothing.
1310 NOTE: this feature can also be enabled for rwlocks, mutexes
1311 and rwsems - in which case all dependencies between these
1312 different locking variants are observed and mapped too, and
1313 the proof of observed correctness is also maintained for an
1314 arbitrary combination of these separate locking variants.
1316 For more details, see Documentation/locking/lockdep-design.rst.
1318 config PROVE_RAW_LOCK_NESTING
1319 bool "Enable raw_spinlock - spinlock nesting checks"
1320 depends on PROVE_LOCKING
1323 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1324 that the lock nesting rules for PREEMPT_RT enabled kernels are
1327 NOTE: There are known nesting problems. So if you enable this
1328 option expect lockdep splats until these problems have been fully
1329 addressed which is work in progress. This config switch allows to
1330 identify and analyze these problems. It will be removed and the
1331 check permanently enabled once the main issues have been fixed.
1333 If unsure, select N.
1336 bool "Lock usage statistics"
1337 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1339 select DEBUG_SPINLOCK
1340 select DEBUG_MUTEXES if !PREEMPT_RT
1341 select DEBUG_RT_MUTEXES if RT_MUTEXES
1342 select DEBUG_LOCK_ALLOC
1345 This feature enables tracking lock contention points
1347 For more details, see Documentation/locking/lockstat.rst
1349 This also enables lock events required by "perf lock",
1351 If you want to use "perf lock", you also need to turn on
1352 CONFIG_EVENT_TRACING.
1354 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1355 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1357 config DEBUG_RT_MUTEXES
1358 bool "RT Mutex debugging, deadlock detection"
1359 depends on DEBUG_KERNEL && RT_MUTEXES
1361 This allows rt mutex semantics violations and rt mutex related
1362 deadlocks (lockups) to be detected and reported automatically.
1364 config DEBUG_SPINLOCK
1365 bool "Spinlock and rw-lock debugging: basic checks"
1366 depends on DEBUG_KERNEL
1367 select UNINLINE_SPIN_UNLOCK
1369 Say Y here and build SMP to catch missing spinlock initialization
1370 and certain other kinds of spinlock errors commonly made. This is
1371 best used in conjunction with the NMI watchdog so that spinlock
1372 deadlocks are also debuggable.
1374 config DEBUG_MUTEXES
1375 bool "Mutex debugging: basic checks"
1376 depends on DEBUG_KERNEL && !PREEMPT_RT
1378 This feature allows mutex semantics violations to be detected and
1381 config DEBUG_WW_MUTEX_SLOWPATH
1382 bool "Wait/wound mutex debugging: Slowpath testing"
1383 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1384 select DEBUG_LOCK_ALLOC
1385 select DEBUG_SPINLOCK
1386 select DEBUG_MUTEXES if !PREEMPT_RT
1387 select DEBUG_RT_MUTEXES if PREEMPT_RT
1389 This feature enables slowpath testing for w/w mutex users by
1390 injecting additional -EDEADLK wound/backoff cases. Together with
1391 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1392 will test all possible w/w mutex interface abuse with the
1393 exception of simply not acquiring all the required locks.
1394 Note that this feature can introduce significant overhead, so
1395 it really should not be enabled in a production or distro kernel,
1396 even a debug kernel. If you are a driver writer, enable it. If
1397 you are a distro, do not.
1400 bool "RW Semaphore debugging: basic checks"
1401 depends on DEBUG_KERNEL
1403 This debugging feature allows mismatched rw semaphore locks
1404 and unlocks to be detected and reported.
1406 config DEBUG_LOCK_ALLOC
1407 bool "Lock debugging: detect incorrect freeing of live locks"
1408 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1409 select DEBUG_SPINLOCK
1410 select DEBUG_MUTEXES if !PREEMPT_RT
1411 select DEBUG_RT_MUTEXES if RT_MUTEXES
1414 This feature will check whether any held lock (spinlock, rwlock,
1415 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1416 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1417 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1418 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1419 held during task exit.
1423 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1428 config LOCKDEP_SMALL
1432 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1433 depends on LOCKDEP && !LOCKDEP_SMALL
1437 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1439 config LOCKDEP_CHAINS_BITS
1440 int "Bitsize for MAX_LOCKDEP_CHAINS"
1441 depends on LOCKDEP && !LOCKDEP_SMALL
1445 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1447 config LOCKDEP_STACK_TRACE_BITS
1448 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1449 depends on LOCKDEP && !LOCKDEP_SMALL
1453 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1455 config LOCKDEP_STACK_TRACE_HASH_BITS
1456 int "Bitsize for STACK_TRACE_HASH_SIZE"
1457 depends on LOCKDEP && !LOCKDEP_SMALL
1461 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1463 config LOCKDEP_CIRCULAR_QUEUE_BITS
1464 int "Bitsize for elements in circular_queue struct"
1469 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1471 config DEBUG_LOCKDEP
1472 bool "Lock dependency engine debugging"
1473 depends on DEBUG_KERNEL && LOCKDEP
1474 select DEBUG_IRQFLAGS
1476 If you say Y here, the lock dependency engine will do
1477 additional runtime checks to debug itself, at the price
1478 of more runtime overhead.
1480 config DEBUG_ATOMIC_SLEEP
1481 bool "Sleep inside atomic section checking"
1482 select PREEMPT_COUNT
1483 depends on DEBUG_KERNEL
1484 depends on !ARCH_NO_PREEMPT
1486 If you say Y here, various routines which may sleep will become very
1487 noisy if they are called inside atomic sections: when a spinlock is
1488 held, inside an rcu read side critical section, inside preempt disabled
1489 sections, inside an interrupt, etc...
1491 config DEBUG_LOCKING_API_SELFTESTS
1492 bool "Locking API boot-time self-tests"
1493 depends on DEBUG_KERNEL
1495 Say Y here if you want the kernel to run a short self-test during
1496 bootup. The self-test checks whether common types of locking bugs
1497 are detected by debugging mechanisms or not. (if you disable
1498 lock debugging then those bugs won't be detected of course.)
1499 The following locking APIs are covered: spinlocks, rwlocks,
1502 config LOCK_TORTURE_TEST
1503 tristate "torture tests for locking"
1504 depends on DEBUG_KERNEL
1507 This option provides a kernel module that runs torture tests
1508 on kernel locking primitives. The kernel module may be built
1509 after the fact on the running kernel to be tested, if desired.
1511 Say Y here if you want kernel locking-primitive torture tests
1512 to be built into the kernel.
1513 Say M if you want these torture tests to build as a module.
1514 Say N if you are unsure.
1516 config WW_MUTEX_SELFTEST
1517 tristate "Wait/wound mutex selftests"
1519 This option provides a kernel module that runs tests on the
1520 on the struct ww_mutex locking API.
1522 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1523 with this test harness.
1525 Say M if you want these self tests to build as a module.
1526 Say N if you are unsure.
1528 config SCF_TORTURE_TEST
1529 tristate "torture tests for smp_call_function*()"
1530 depends on DEBUG_KERNEL
1533 This option provides a kernel module that runs torture tests
1534 on the smp_call_function() family of primitives. The kernel
1535 module may be built after the fact on the running kernel to
1536 be tested, if desired.
1538 config CSD_LOCK_WAIT_DEBUG
1539 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1540 depends on DEBUG_KERNEL
1544 This option enables debug prints when CPUs are slow to respond
1545 to the smp_call_function*() IPI wrappers. These debug prints
1546 include the IPI handler function currently executing (if any)
1547 and relevant stack traces.
1550 prompt "Lock debugging: prove subsystem device_lock() correctness"
1551 depends on PROVE_LOCKING
1553 For subsystems that have instrumented their usage of the device_lock()
1554 with nested annotations, enable lock dependency checking. The locking
1555 hierarchy 'subclass' identifiers are not compatible across
1556 sub-systems, so only one can be enabled at a time.
1558 config PROVE_NVDIMM_LOCKING
1560 depends on LIBNVDIMM
1562 Enable lockdep to validate nd_device_lock() usage.
1564 config PROVE_CXL_LOCKING
1568 Enable lockdep to validate cxl_device_lock() usage.
1572 endmenu # lock debugging
1574 config TRACE_IRQFLAGS
1575 depends on TRACE_IRQFLAGS_SUPPORT
1578 Enables hooks to interrupt enabling and disabling for
1579 either tracing or lock debugging.
1581 config TRACE_IRQFLAGS_NMI
1583 depends on TRACE_IRQFLAGS
1584 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1586 config DEBUG_IRQFLAGS
1587 bool "Debug IRQ flag manipulation"
1589 Enables checks for potentially unsafe enabling or disabling of
1590 interrupts, such as calling raw_local_irq_restore() when interrupts
1594 bool "Stack backtrace support"
1595 depends on STACKTRACE_SUPPORT
1597 This option causes the kernel to create a /proc/pid/stack for
1598 every process, showing its current stack trace.
1599 It is also used by various kernel debugging features that require
1600 stack trace generation.
1602 config WARN_ALL_UNSEEDED_RANDOM
1603 bool "Warn for all uses of unseeded randomness"
1606 Some parts of the kernel contain bugs relating to their use of
1607 cryptographically secure random numbers before it's actually possible
1608 to generate those numbers securely. This setting ensures that these
1609 flaws don't go unnoticed, by enabling a message, should this ever
1610 occur. This will allow people with obscure setups to know when things
1611 are going wrong, so that they might contact developers about fixing
1614 Unfortunately, on some models of some architectures getting
1615 a fully seeded CRNG is extremely difficult, and so this can
1616 result in dmesg getting spammed for a surprisingly long
1617 time. This is really bad from a security perspective, and
1618 so architecture maintainers really need to do what they can
1619 to get the CRNG seeded sooner after the system is booted.
1620 However, since users cannot do anything actionable to
1621 address this, by default this option is disabled.
1623 Say Y here if you want to receive warnings for all uses of
1624 unseeded randomness. This will be of use primarily for
1625 those developers interested in improving the security of
1626 Linux kernels running on their architecture (or
1629 config DEBUG_KOBJECT
1630 bool "kobject debugging"
1631 depends on DEBUG_KERNEL
1633 If you say Y here, some extra kobject debugging messages will be sent
1636 config DEBUG_KOBJECT_RELEASE
1637 bool "kobject release debugging"
1638 depends on DEBUG_OBJECTS_TIMERS
1640 kobjects are reference counted objects. This means that their
1641 last reference count put is not predictable, and the kobject can
1642 live on past the point at which a driver decides to drop it's
1643 initial reference to the kobject gained on allocation. An
1644 example of this would be a struct device which has just been
1647 However, some buggy drivers assume that after such an operation,
1648 the memory backing the kobject can be immediately freed. This
1649 goes completely against the principles of a refcounted object.
1651 If you say Y here, the kernel will delay the release of kobjects
1652 on the last reference count to improve the visibility of this
1653 kind of kobject release bug.
1655 config HAVE_DEBUG_BUGVERBOSE
1658 menu "Debug kernel data structures"
1661 bool "Debug linked list manipulation"
1662 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1664 Enable this to turn on extended checks in the linked-list
1670 bool "Debug priority linked list manipulation"
1671 depends on DEBUG_KERNEL
1673 Enable this to turn on extended checks in the priority-ordered
1674 linked-list (plist) walking routines. This checks the entire
1675 list multiple times during each manipulation.
1680 bool "Debug SG table operations"
1681 depends on DEBUG_KERNEL
1683 Enable this to turn on checks on scatter-gather tables. This can
1684 help find problems with drivers that do not properly initialize
1689 config DEBUG_NOTIFIERS
1690 bool "Debug notifier call chains"
1691 depends on DEBUG_KERNEL
1693 Enable this to turn on sanity checking for notifier call chains.
1694 This is most useful for kernel developers to make sure that
1695 modules properly unregister themselves from notifier chains.
1696 This is a relatively cheap check but if you care about maximum
1699 config BUG_ON_DATA_CORRUPTION
1700 bool "Trigger a BUG when data corruption is detected"
1703 Select this option if the kernel should BUG when it encounters
1704 data corruption in kernel memory structures when they get checked
1711 config DEBUG_CREDENTIALS
1712 bool "Debug credential management"
1713 depends on DEBUG_KERNEL
1715 Enable this to turn on some debug checking for credential
1716 management. The additional code keeps track of the number of
1717 pointers from task_structs to any given cred struct, and checks to
1718 see that this number never exceeds the usage count of the cred
1721 Furthermore, if SELinux is enabled, this also checks that the
1722 security pointer in the cred struct is never seen to be invalid.
1726 source "kernel/rcu/Kconfig.debug"
1728 config DEBUG_WQ_FORCE_RR_CPU
1729 bool "Force round-robin CPU selection for unbound work items"
1730 depends on DEBUG_KERNEL
1733 Workqueue used to implicitly guarantee that work items queued
1734 without explicit CPU specified are put on the local CPU. This
1735 guarantee is no longer true and while local CPU is still
1736 preferred work items may be put on foreign CPUs. Kernel
1737 parameter "workqueue.debug_force_rr_cpu" is added to force
1738 round-robin CPU selection to flush out usages which depend on the
1739 now broken guarantee. This config option enables the debug
1740 feature by default. When enabled, memory and cache locality will
1743 config CPU_HOTPLUG_STATE_CONTROL
1744 bool "Enable CPU hotplug state control"
1745 depends on DEBUG_KERNEL
1746 depends on HOTPLUG_CPU
1749 Allows to write steps between "offline" and "online" to the CPUs
1750 sysfs target file so states can be stepped granular. This is a debug
1751 option for now as the hotplug machinery cannot be stopped and
1752 restarted at arbitrary points yet.
1754 Say N if your are unsure.
1757 bool "Latency measuring infrastructure"
1758 depends on DEBUG_KERNEL
1759 depends on STACKTRACE_SUPPORT
1761 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1767 Enable this option if you want to use the LatencyTOP tool
1768 to find out which userspace is blocking on what kernel operations.
1770 source "kernel/trace/Kconfig"
1772 config PROVIDE_OHCI1394_DMA_INIT
1773 bool "Remote debugging over FireWire early on boot"
1774 depends on PCI && X86
1776 If you want to debug problems which hang or crash the kernel early
1777 on boot and the crashing machine has a FireWire port, you can use
1778 this feature to remotely access the memory of the crashed machine
1779 over FireWire. This employs remote DMA as part of the OHCI1394
1780 specification which is now the standard for FireWire controllers.
1782 With remote DMA, you can monitor the printk buffer remotely using
1783 firescope and access all memory below 4GB using fireproxy from gdb.
1784 Even controlling a kernel debugger is possible using remote DMA.
1788 If ohci1394_dma=early is used as boot parameter, it will initialize
1789 all OHCI1394 controllers which are found in the PCI config space.
1791 As all changes to the FireWire bus such as enabling and disabling
1792 devices cause a bus reset and thereby disable remote DMA for all
1793 devices, be sure to have the cable plugged and FireWire enabled on
1794 the debugging host before booting the debug target for debugging.
1796 This code (~1k) is freed after boot. By then, the firewire stack
1797 in charge of the OHCI-1394 controllers should be used instead.
1799 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1801 source "samples/Kconfig"
1803 config ARCH_HAS_DEVMEM_IS_ALLOWED
1806 config STRICT_DEVMEM
1807 bool "Filter access to /dev/mem"
1808 depends on MMU && DEVMEM
1809 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1810 default y if PPC || X86 || ARM64
1812 If this option is disabled, you allow userspace (root) access to all
1813 of memory, including kernel and userspace memory. Accidental
1814 access to this is obviously disastrous, but specific access can
1815 be used by people debugging the kernel. Note that with PAT support
1816 enabled, even in this case there are restrictions on /dev/mem
1817 use due to the cache aliasing requirements.
1819 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1820 file only allows userspace access to PCI space and the BIOS code and
1821 data regions. This is sufficient for dosemu and X and all common
1826 config IO_STRICT_DEVMEM
1827 bool "Filter I/O access to /dev/mem"
1828 depends on STRICT_DEVMEM
1830 If this option is disabled, you allow userspace (root) access to all
1831 io-memory regardless of whether a driver is actively using that
1832 range. Accidental access to this is obviously disastrous, but
1833 specific access can be used by people debugging kernel drivers.
1835 If this option is switched on, the /dev/mem file only allows
1836 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1837 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1838 if the driver using a given range cannot be disabled.
1842 menu "$(SRCARCH) Debugging"
1844 source "arch/$(SRCARCH)/Kconfig.debug"
1848 menu "Kernel Testing and Coverage"
1850 source "lib/kunit/Kconfig"
1852 config NOTIFIER_ERROR_INJECTION
1853 tristate "Notifier error injection"
1854 depends on DEBUG_KERNEL
1857 This option provides the ability to inject artificial errors to
1858 specified notifier chain callbacks. It is useful to test the error
1859 handling of notifier call chain failures.
1863 config PM_NOTIFIER_ERROR_INJECT
1864 tristate "PM notifier error injection module"
1865 depends on PM && NOTIFIER_ERROR_INJECTION
1866 default m if PM_DEBUG
1868 This option provides the ability to inject artificial errors to
1869 PM notifier chain callbacks. It is controlled through debugfs
1870 interface /sys/kernel/debug/notifier-error-inject/pm
1872 If the notifier call chain should be failed with some events
1873 notified, write the error code to "actions/<notifier event>/error".
1875 Example: Inject PM suspend error (-12 = -ENOMEM)
1877 # cd /sys/kernel/debug/notifier-error-inject/pm/
1878 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1879 # echo mem > /sys/power/state
1880 bash: echo: write error: Cannot allocate memory
1882 To compile this code as a module, choose M here: the module will
1883 be called pm-notifier-error-inject.
1887 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1888 tristate "OF reconfig notifier error injection module"
1889 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1891 This option provides the ability to inject artificial errors to
1892 OF reconfig notifier chain callbacks. It is controlled
1893 through debugfs interface under
1894 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1896 If the notifier call chain should be failed with some events
1897 notified, write the error code to "actions/<notifier event>/error".
1899 To compile this code as a module, choose M here: the module will
1900 be called of-reconfig-notifier-error-inject.
1904 config NETDEV_NOTIFIER_ERROR_INJECT
1905 tristate "Netdev notifier error injection module"
1906 depends on NET && NOTIFIER_ERROR_INJECTION
1908 This option provides the ability to inject artificial errors to
1909 netdevice notifier chain callbacks. It is controlled through debugfs
1910 interface /sys/kernel/debug/notifier-error-inject/netdev
1912 If the notifier call chain should be failed with some events
1913 notified, write the error code to "actions/<notifier event>/error".
1915 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1917 # cd /sys/kernel/debug/notifier-error-inject/netdev
1918 # echo -22 > actions/NETDEV_CHANGEMTU/error
1919 # ip link set eth0 mtu 1024
1920 RTNETLINK answers: Invalid argument
1922 To compile this code as a module, choose M here: the module will
1923 be called netdev-notifier-error-inject.
1927 config FUNCTION_ERROR_INJECTION
1929 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1931 config FAULT_INJECTION
1932 bool "Fault-injection framework"
1933 depends on DEBUG_KERNEL
1935 Provide fault-injection framework.
1936 For more details, see Documentation/fault-injection/.
1939 bool "Fault-injection capability for kmalloc"
1940 depends on FAULT_INJECTION
1941 depends on SLAB || SLUB
1943 Provide fault-injection capability for kmalloc.
1945 config FAIL_PAGE_ALLOC
1946 bool "Fault-injection capability for alloc_pages()"
1947 depends on FAULT_INJECTION
1949 Provide fault-injection capability for alloc_pages().
1951 config FAULT_INJECTION_USERCOPY
1952 bool "Fault injection capability for usercopy functions"
1953 depends on FAULT_INJECTION
1955 Provides fault-injection capability to inject failures
1956 in usercopy functions (copy_from_user(), get_user(), ...).
1958 config FAIL_MAKE_REQUEST
1959 bool "Fault-injection capability for disk IO"
1960 depends on FAULT_INJECTION && BLOCK
1962 Provide fault-injection capability for disk IO.
1964 config FAIL_IO_TIMEOUT
1965 bool "Fault-injection capability for faking disk interrupts"
1966 depends on FAULT_INJECTION && BLOCK
1968 Provide fault-injection capability on end IO handling. This
1969 will make the block layer "forget" an interrupt as configured,
1970 thus exercising the error handling.
1972 Only works with drivers that use the generic timeout handling,
1973 for others it won't do anything.
1976 bool "Fault-injection capability for futexes"
1978 depends on FAULT_INJECTION && FUTEX
1980 Provide fault-injection capability for futexes.
1982 config FAULT_INJECTION_DEBUG_FS
1983 bool "Debugfs entries for fault-injection capabilities"
1984 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1986 Enable configuration of fault-injection capabilities via debugfs.
1988 config FAIL_FUNCTION
1989 bool "Fault-injection capability for functions"
1990 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1992 Provide function-based fault-injection capability.
1993 This will allow you to override a specific function with a return
1994 with given return value. As a result, function caller will see
1995 an error value and have to handle it. This is useful to test the
1996 error handling in various subsystems.
1998 config FAIL_MMC_REQUEST
1999 bool "Fault-injection capability for MMC IO"
2000 depends on FAULT_INJECTION_DEBUG_FS && MMC
2002 Provide fault-injection capability for MMC IO.
2003 This will make the mmc core return data errors. This is
2004 useful to test the error handling in the mmc block device
2005 and to test how the mmc host driver handles retries from
2009 bool "Fault-injection capability for SunRPC"
2010 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2012 Provide fault-injection capability for SunRPC and
2015 config FAULT_INJECTION_STACKTRACE_FILTER
2016 bool "stacktrace filter for fault-injection capabilities"
2017 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
2020 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2022 Provide stacktrace filter for fault-injection capabilities
2024 config ARCH_HAS_KCOV
2027 An architecture should select this when it can successfully
2028 build and run with CONFIG_KCOV. This typically requires
2029 disabling instrumentation for some early boot code.
2031 config CC_HAS_SANCOV_TRACE_PC
2032 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2036 bool "Code coverage for fuzzing"
2037 depends on ARCH_HAS_KCOV
2038 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2039 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2040 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
2042 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2043 select OBJTOOL if HAVE_NOINSTR_HACK
2045 KCOV exposes kernel code coverage information in a form suitable
2046 for coverage-guided fuzzing (randomized testing).
2048 If RANDOMIZE_BASE is enabled, PC values will not be stable across
2049 different machines and across reboots. If you need stable PC values,
2050 disable RANDOMIZE_BASE.
2052 For more details, see Documentation/dev-tools/kcov.rst.
2054 config KCOV_ENABLE_COMPARISONS
2055 bool "Enable comparison operands collection by KCOV"
2057 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2059 KCOV also exposes operands of every comparison in the instrumented
2060 code along with operand sizes and PCs of the comparison instructions.
2061 These operands can be used by fuzzing engines to improve the quality
2062 of fuzzing coverage.
2064 config KCOV_INSTRUMENT_ALL
2065 bool "Instrument all code by default"
2069 If you are doing generic system call fuzzing (like e.g. syzkaller),
2070 then you will want to instrument the whole kernel and you should
2071 say y here. If you are doing more targeted fuzzing (like e.g.
2072 filesystem fuzzing with AFL) then you will want to enable coverage
2073 for more specific subsets of files, and should say n here.
2075 config KCOV_IRQ_AREA_SIZE
2076 hex "Size of interrupt coverage collection area in words"
2080 KCOV uses preallocated per-cpu areas to collect coverage from
2081 soft interrupts. This specifies the size of those areas in the
2082 number of unsigned long words.
2084 menuconfig RUNTIME_TESTING_MENU
2085 bool "Runtime Testing"
2088 if RUNTIME_TESTING_MENU
2091 tristate "Linux Kernel Dump Test Tool Module"
2094 This module enables testing of the different dumping mechanisms by
2095 inducing system failures at predefined crash points.
2096 If you don't need it: say N
2097 Choose M here to compile this code as a module. The module will be
2100 Documentation on how to use the module can be found in
2101 Documentation/fault-injection/provoke-crashes.rst
2103 config TEST_LIST_SORT
2104 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2106 default KUNIT_ALL_TESTS
2108 Enable this to turn on 'list_sort()' function test. This test is
2109 executed only once during system boot (so affects only boot time),
2110 or at module load time.
2114 config TEST_MIN_HEAP
2115 tristate "Min heap test"
2116 depends on DEBUG_KERNEL || m
2118 Enable this to turn on min heap function tests. This test is
2119 executed only once during system boot (so affects only boot time),
2120 or at module load time.
2125 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2127 default KUNIT_ALL_TESTS
2129 This option enables the self-test function of 'sort()' at boot,
2130 or at module load time.
2135 tristate "64bit/32bit division and modulo test"
2136 depends on DEBUG_KERNEL || m
2138 Enable this to turn on 'do_div()' function test. This test is
2139 executed only once during system boot (so affects only boot time),
2140 or at module load time.
2144 config KPROBES_SANITY_TEST
2145 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2146 depends on DEBUG_KERNEL
2149 default KUNIT_ALL_TESTS
2151 This option provides for testing basic kprobes functionality on
2152 boot. Samples of kprobe and kretprobe are inserted and
2153 verified for functionality.
2155 Say N if you are unsure.
2157 config FPROBE_SANITY_TEST
2158 bool "Self test for fprobe"
2159 depends on DEBUG_KERNEL
2163 This option will enable testing the fprobe when the system boot.
2164 A series of tests are made to verify that the fprobe is functioning
2167 Say N if you are unsure.
2169 config BACKTRACE_SELF_TEST
2170 tristate "Self test for the backtrace code"
2171 depends on DEBUG_KERNEL
2173 This option provides a kernel module that can be used to test
2174 the kernel stack backtrace code. This option is not useful
2175 for distributions or general kernels, but only for kernel
2176 developers working on architecture code.
2178 Note that if you want to also test saved backtraces, you will
2179 have to enable STACKTRACE as well.
2181 Say N if you are unsure.
2183 config TEST_REF_TRACKER
2184 tristate "Self test for reference tracker"
2185 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2188 This option provides a kernel module performing tests
2189 using reference tracker infrastructure.
2191 Say N if you are unsure.
2194 tristate "Red-Black tree test"
2195 depends on DEBUG_KERNEL
2197 A benchmark measuring the performance of the rbtree library.
2198 Also includes rbtree invariant checks.
2200 config REED_SOLOMON_TEST
2201 tristate "Reed-Solomon library test"
2202 depends on DEBUG_KERNEL || m
2204 select REED_SOLOMON_ENC16
2205 select REED_SOLOMON_DEC16
2207 This option enables the self-test function of rslib at boot,
2208 or at module load time.
2212 config INTERVAL_TREE_TEST
2213 tristate "Interval tree test"
2214 depends on DEBUG_KERNEL
2215 select INTERVAL_TREE
2217 A benchmark measuring the performance of the interval tree library
2220 tristate "Per cpu operations test"
2221 depends on m && DEBUG_KERNEL
2223 Enable this option to build test module which validates per-cpu
2228 config ATOMIC64_SELFTEST
2229 tristate "Perform an atomic64_t self-test"
2231 Enable this option to test the atomic64_t functions at boot or
2232 at module load time.
2236 config ASYNC_RAID6_TEST
2237 tristate "Self test for hardware accelerated raid6 recovery"
2238 depends on ASYNC_RAID6_RECOV
2241 This is a one-shot self test that permutes through the
2242 recovery of all the possible two disk failure scenarios for a
2243 N-disk array. Recovery is performed with the asynchronous
2244 raid6 recovery routines, and will optionally use an offload
2245 engine if one is available.
2250 tristate "Test functions located in the hexdump module at runtime"
2252 config STRING_SELFTEST
2253 tristate "Test string functions at runtime"
2255 config TEST_STRING_HELPERS
2256 tristate "Test functions located in the string_helpers module at runtime"
2259 tristate "Test strscpy*() family of functions at runtime"
2262 tristate "Test kstrto*() family of functions at runtime"
2265 tristate "Test printf() family of functions at runtime"
2268 tristate "Test scanf() family of functions at runtime"
2271 tristate "Test bitmap_*() family of functions at runtime"
2273 Enable this option to test the bitmap functions at boot.
2278 tristate "Test functions located in the uuid module at runtime"
2281 tristate "Test the XArray code at runtime"
2283 config TEST_RHASHTABLE
2284 tristate "Perform selftest on resizable hash table"
2286 Enable this option to test the rhashtable functions at boot.
2291 tristate "Perform selftest on siphash functions"
2293 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2294 functions on boot (or module load).
2296 This is intended to help people writing architecture-specific
2297 optimized versions. If unsure, say N.
2300 tristate "Perform selftest on IDA functions"
2303 tristate "Perform selftest on priority array manager"
2306 Enable this option to test priority array manager on boot
2311 config TEST_IRQ_TIMINGS
2312 bool "IRQ timings selftest"
2313 depends on IRQ_TIMINGS
2315 Enable this option to test the irq timings code on boot.
2320 tristate "Test module loading with 'hello world' module"
2323 This builds the "test_module" module that emits "Hello, world"
2324 on printk when loaded. It is designed to be used for basic
2325 evaluation of the module loading subsystem (for example when
2326 validating module verification). It lacks any extra dependencies,
2327 and will not normally be loaded by the system unless explicitly
2333 tristate "Test module for compilation of bitops operations"
2336 This builds the "test_bitops" module that is much like the
2337 TEST_LKM module except that it does a basic exercise of the
2338 set/clear_bit macros and get_count_order/long to make sure there are
2339 no compiler warnings from C=1 sparse checker or -Wextra
2340 compilations. It has no dependencies and doesn't run or load unless
2341 explicitly requested by name. for example: modprobe test_bitops.
2346 tristate "Test module for stress/performance analysis of vmalloc allocator"
2351 This builds the "test_vmalloc" module that should be used for
2352 stress and performance analysis. So, any new change for vmalloc
2353 subsystem can be evaluated from performance and stability point
2358 config TEST_USER_COPY
2359 tristate "Test user/kernel boundary protections"
2362 This builds the "test_user_copy" module that runs sanity checks
2363 on the copy_to/from_user infrastructure, making sure basic
2364 user/kernel boundary testing is working. If it fails to load,
2365 a regression has been detected in the user/kernel memory boundary
2371 tristate "Test BPF filter functionality"
2374 This builds the "test_bpf" module that runs various test vectors
2375 against the BPF interpreter or BPF JIT compiler depending on the
2376 current setting. This is in particular useful for BPF JIT compiler
2377 development, but also to run regression tests against changes in
2378 the interpreter code. It also enables test stubs for eBPF maps and
2379 verifier used by user space verifier testsuite.
2383 config TEST_BLACKHOLE_DEV
2384 tristate "Test blackhole netdev functionality"
2387 This builds the "test_blackhole_dev" module that validates the
2388 data path through this blackhole netdev.
2392 config FIND_BIT_BENCHMARK
2393 tristate "Test find_bit functions"
2395 This builds the "test_find_bit" module that measure find_*_bit()
2396 functions performance.
2400 config TEST_FIRMWARE
2401 tristate "Test firmware loading via userspace interface"
2402 depends on FW_LOADER
2404 This builds the "test_firmware" module that creates a userspace
2405 interface for testing firmware loading. This can be used to
2406 control the triggering of firmware loading without needing an
2407 actual firmware-using device. The contents can be rechecked by
2413 tristate "sysctl test driver"
2414 depends on PROC_SYSCTL
2416 This builds the "test_sysctl" module. This driver enables to test the
2417 proc sysctl interfaces available to drivers safely without affecting
2418 production knobs which might alter system functionality.
2422 config BITFIELD_KUNIT
2423 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2425 default KUNIT_ALL_TESTS
2427 Enable this option to test the bitfield functions at boot.
2429 KUnit tests run during boot and output the results to the debug log
2430 in TAP format (http://testanything.org/). Only useful for kernel devs
2431 running the KUnit test harness, and not intended for inclusion into a
2434 For more information on KUnit and unit tests in general please refer
2435 to the KUnit documentation in Documentation/dev-tools/kunit/.
2439 config HASH_KUNIT_TEST
2440 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2442 default KUNIT_ALL_TESTS
2444 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2445 integer (<linux/hash.h>) hash functions on boot.
2447 KUnit tests run during boot and output the results to the debug log
2448 in TAP format (https://testanything.org/). Only useful for kernel devs
2449 running the KUnit test harness, and not intended for inclusion into a
2452 For more information on KUnit and unit tests in general please refer
2453 to the KUnit documentation in Documentation/dev-tools/kunit/.
2455 This is intended to help people writing architecture-specific
2456 optimized versions. If unsure, say N.
2458 config RESOURCE_KUNIT_TEST
2459 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2461 default KUNIT_ALL_TESTS
2463 This builds the resource API unit test.
2464 Tests the logic of API provided by resource.c and ioport.h.
2465 For more information on KUnit and unit tests in general please refer
2466 to the KUnit documentation in Documentation/dev-tools/kunit/.
2470 config SYSCTL_KUNIT_TEST
2471 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2473 default KUNIT_ALL_TESTS
2475 This builds the proc sysctl unit test, which runs on boot.
2476 Tests the API contract and implementation correctness of sysctl.
2477 For more information on KUnit and unit tests in general please refer
2478 to the KUnit documentation in Documentation/dev-tools/kunit/.
2482 config LIST_KUNIT_TEST
2483 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2485 default KUNIT_ALL_TESTS
2487 This builds the linked list KUnit test suite.
2488 It tests that the API and basic functionality of the list_head type
2489 and associated macros.
2491 KUnit tests run during boot and output the results to the debug log
2492 in TAP format (https://testanything.org/). Only useful for kernel devs
2493 running the KUnit test harness, and not intended for inclusion into a
2496 For more information on KUnit and unit tests in general please refer
2497 to the KUnit documentation in Documentation/dev-tools/kunit/.
2501 config LINEAR_RANGES_TEST
2502 tristate "KUnit test for linear_ranges"
2504 select LINEAR_RANGES
2506 This builds the linear_ranges unit test, which runs on boot.
2507 Tests the linear_ranges logic correctness.
2508 For more information on KUnit and unit tests in general please refer
2509 to the KUnit documentation in Documentation/dev-tools/kunit/.
2513 config CMDLINE_KUNIT_TEST
2514 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2516 default KUNIT_ALL_TESTS
2518 This builds the cmdline API unit test.
2519 Tests the logic of API provided by cmdline.c.
2520 For more information on KUnit and unit tests in general please refer
2521 to the KUnit documentation in Documentation/dev-tools/kunit/.
2526 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2528 default KUNIT_ALL_TESTS
2530 This builds the bits unit test.
2531 Tests the logic of macros defined in bits.h.
2532 For more information on KUnit and unit tests in general please refer
2533 to the KUnit documentation in Documentation/dev-tools/kunit/.
2537 config SLUB_KUNIT_TEST
2538 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2539 depends on SLUB_DEBUG && KUNIT
2540 default KUNIT_ALL_TESTS
2542 This builds SLUB allocator unit test.
2543 Tests SLUB cache debugging functionality.
2544 For more information on KUnit and unit tests in general please refer
2545 to the KUnit documentation in Documentation/dev-tools/kunit/.
2549 config RATIONAL_KUNIT_TEST
2550 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2551 depends on KUNIT && RATIONAL
2552 default KUNIT_ALL_TESTS
2554 This builds the rational math unit test.
2555 For more information on KUnit and unit tests in general please refer
2556 to the KUnit documentation in Documentation/dev-tools/kunit/.
2560 config MEMCPY_KUNIT_TEST
2561 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2563 default KUNIT_ALL_TESTS
2565 Builds unit tests for memcpy(), memmove(), and memset() functions.
2566 For more information on KUnit and unit tests in general please refer
2567 to the KUnit documentation in Documentation/dev-tools/kunit/.
2571 config OVERFLOW_KUNIT_TEST
2572 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2574 default KUNIT_ALL_TESTS
2576 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2579 For more information on KUnit and unit tests in general please refer
2580 to the KUnit documentation in Documentation/dev-tools/kunit/.
2584 config STACKINIT_KUNIT_TEST
2585 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2587 default KUNIT_ALL_TESTS
2589 Test if the kernel is zero-initializing stack variables and
2590 padding. Coverage is controlled by compiler flags,
2591 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2592 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2593 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2596 tristate "udelay test driver"
2598 This builds the "udelay_test" module that helps to make sure
2599 that udelay() is working properly.
2603 config TEST_STATIC_KEYS
2604 tristate "Test static keys"
2607 Test the static key interfaces.
2612 tristate "kmod stress tester"
2614 depends on NETDEVICES && NET_CORE && INET # for TUN
2616 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2622 Test the kernel's module loading mechanism: kmod. kmod implements
2623 support to load modules using the Linux kernel's usermode helper.
2624 This test provides a series of tests against kmod.
2626 Although technically you can either build test_kmod as a module or
2627 into the kernel we disallow building it into the kernel since
2628 it stress tests request_module() and this will very likely cause
2629 some issues by taking over precious threads available from other
2630 module load requests, ultimately this could be fatal.
2634 tools/testing/selftests/kmod/kmod.sh --help
2638 config TEST_DEBUG_VIRTUAL
2639 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2640 depends on DEBUG_VIRTUAL
2642 Test the kernel's ability to detect incorrect calls to
2643 virt_to_phys() done against the non-linear part of the
2644 kernel's virtual address map.
2648 config TEST_MEMCAT_P
2649 tristate "Test memcat_p() helper function"
2651 Test the memcat_p() helper for correctly merging two
2652 pointer arrays together.
2656 config TEST_LIVEPATCH
2657 tristate "Test livepatching"
2659 depends on DYNAMIC_DEBUG
2660 depends on LIVEPATCH
2663 Test kernel livepatching features for correctness. The tests will
2664 load test modules that will be livepatched in various scenarios.
2666 To run all the livepatching tests:
2668 make -C tools/testing/selftests TARGETS=livepatch run_tests
2670 Alternatively, individual tests may be invoked:
2672 tools/testing/selftests/livepatch/test-callbacks.sh
2673 tools/testing/selftests/livepatch/test-livepatch.sh
2674 tools/testing/selftests/livepatch/test-shadow-vars.sh
2679 tristate "Perform selftest on object aggreration manager"
2683 Enable this option to test object aggregation manager on boot
2687 tristate "Test heap/page initialization"
2689 Test if the kernel is zero-initializing heap and page allocations.
2690 This can be useful to test init_on_alloc and init_on_free features.
2695 tristate "Test HMM (Heterogeneous Memory Management)"
2696 depends on TRANSPARENT_HUGEPAGE
2697 depends on DEVICE_PRIVATE
2701 This is a pseudo device driver solely for testing HMM.
2702 Say M here if you want to build the HMM test module.
2703 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2707 config TEST_FREE_PAGES
2708 tristate "Test freeing pages"
2710 Test that a memory leak does not occur due to a race between
2711 freeing a block of pages and a speculative page reference.
2712 Loading this module is safe if your kernel has the bug fixed.
2713 If the bug is not fixed, it will leak gigabytes of memory and
2714 probably OOM your system.
2717 tristate "Test floating point operations in kernel space"
2718 depends on X86 && !KCOV_INSTRUMENT_ALL
2720 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2721 which will trigger a sequence of floating point operations. This is used
2722 for self-testing floating point control register setting in
2727 config TEST_CLOCKSOURCE_WATCHDOG
2728 tristate "Test clocksource watchdog in kernel space"
2729 depends on CLOCKSOURCE_WATCHDOG
2731 Enable this option to create a kernel module that will trigger
2732 a test of the clocksource watchdog. This module may be loaded
2733 via modprobe or insmod in which case it will run upon being
2734 loaded, or it may be built in, in which case it will run
2739 endif # RUNTIME_TESTING_MENU
2741 config ARCH_USE_MEMTEST
2744 An architecture should select this when it uses early_memtest()
2745 during boot process.
2749 depends on ARCH_USE_MEMTEST
2751 This option adds a kernel parameter 'memtest', which allows memtest
2752 to be set and executed.
2753 memtest=0, mean disabled; -- default
2754 memtest=1, mean do 1 test pattern;
2756 memtest=17, mean do 17 test patterns.
2757 If you are unsure how to answer this question, answer N.
2761 config HYPERV_TESTING
2762 bool "Microsoft Hyper-V driver testing"
2764 depends on HYPERV && DEBUG_FS
2766 Select this option to enable Hyper-V vmbus testing.
2768 endmenu # "Kernel Testing and Coverage"
2770 source "Documentation/Kconfig"
2772 endmenu # Kernel hacking
projects / linux-2.6-microblaze.git / blob