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"
211 menu "Compile-time checks and compiler options"
214 bool "Compile the kernel with debug info"
215 depends on DEBUG_KERNEL && !COMPILE_TEST
217 If you say Y here the resulting kernel image will include
218 debugging info resulting in a larger kernel image.
219 This adds debug symbols to the kernel and modules (gcc -g), and
220 is needed if you intend to use kernel crashdump or binary object
221 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
222 Say Y here only if you plan to debug the kernel.
228 config DEBUG_INFO_REDUCED
229 bool "Reduce debugging information"
231 If you say Y here gcc is instructed to generate less debugging
232 information for structure types. This means that tools that
233 need full debugging information (like kgdb or systemtap) won't
234 be happy. But if you merely need debugging information to
235 resolve line numbers there is no loss. Advantage is that
236 build directory object sizes shrink dramatically over a full
237 DEBUG_INFO build and compile times are reduced too.
238 Only works with newer gcc versions.
240 config DEBUG_INFO_COMPRESSED
241 bool "Compressed debugging information"
242 depends on $(cc-option,-gz=zlib)
243 depends on $(ld-option,--compress-debug-sections=zlib)
245 Compress the debug information using zlib. Requires GCC 5.0+ or Clang
246 5.0+, binutils 2.26+, and zlib.
248 Users of dpkg-deb via scripts/package/builddeb may find an increase in
249 size of their debug .deb packages with this config set, due to the
250 debug info being compressed with zlib, then the object files being
251 recompressed with a different compression scheme. But this is still
252 preferable to setting $KDEB_COMPRESS to "none" which would be even
255 config DEBUG_INFO_SPLIT
256 bool "Produce split debuginfo in .dwo files"
257 depends on $(cc-option,-gsplit-dwarf)
259 Generate debug info into separate .dwo files. This significantly
260 reduces the build directory size for builds with DEBUG_INFO,
261 because it stores the information only once on disk in .dwo
262 files instead of multiple times in object files and executables.
263 In addition the debug information is also compressed.
265 Requires recent gcc (4.7+) and recent gdb/binutils.
266 Any tool that packages or reads debug information would need
267 to know about the .dwo files and include them.
268 Incompatible with older versions of ccache.
271 prompt "DWARF version"
273 Which version of DWARF debug info to emit.
275 config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
276 bool "Rely on the toolchain's implicit default DWARF version"
278 The implicit default version of DWARF debug info produced by a
279 toolchain changes over time.
281 This can break consumers of the debug info that haven't upgraded to
282 support newer revisions, and prevent testing newer versions, but
283 those should be less common scenarios.
287 config DEBUG_INFO_DWARF4
288 bool "Generate DWARF Version 4 debuginfo"
290 Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+.
292 If you have consumers of DWARF debug info that are not ready for
293 newer revisions of DWARF, you may wish to choose this or have your
296 config DEBUG_INFO_DWARF5
297 bool "Generate DWARF Version 5 debuginfo"
298 depends on GCC_VERSION >= 50000 || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)))
299 depends on !DEBUG_INFO_BTF
301 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
302 5.0+ accepts the -gdwarf-5 flag but only had partial support for some
303 draft features until 7.0), and gdb 8.0+.
305 Changes to the structure of debug info in Version 5 allow for around
306 15-18% savings in resulting image and debug info section sizes as
307 compared to DWARF Version 4. DWARF Version 5 standardizes previous
308 extensions such as accelerators for symbol indexing and the format
309 for fission (.dwo/.dwp) files. Users may not want to select this
310 config if they rely on tooling that has not yet been updated to
311 support DWARF Version 5.
313 endchoice # "DWARF version"
315 config DEBUG_INFO_BTF
316 bool "Generate BTF typeinfo"
317 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
318 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
320 Generate deduplicated BTF type information from DWARF debug info.
321 Turning this on expects presence of pahole tool, which will convert
322 DWARF type info into equivalent deduplicated BTF type info.
324 config PAHOLE_HAS_SPLIT_BTF
325 def_bool $(success, test `$(PAHOLE) --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/'` -ge "119")
327 config DEBUG_INFO_BTF_MODULES
329 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
331 Generate compact split BTF type information for kernel modules.
334 bool "Provide GDB scripts for kernel debugging"
336 This creates the required links to GDB helper scripts in the
337 build directory. If you load vmlinux into gdb, the helper
338 scripts will be automatically imported by gdb as well, and
339 additional functions are available to analyze a Linux kernel
340 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
346 int "Warn for stack frames larger than"
348 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
349 default 1536 if (!64BIT && PARISC)
350 default 1024 if (!64BIT && !PARISC)
351 default 2048 if 64BIT
353 Tell gcc to warn at build time for stack frames larger than this.
354 Setting this too low will cause a lot of warnings.
355 Setting it to 0 disables the warning.
357 config STRIP_ASM_SYMS
358 bool "Strip assembler-generated symbols during link"
361 Strip internal assembler-generated symbols during a link (symbols
362 that look like '.Lxxx') so they don't pollute the output of
363 get_wchan() and suchlike.
366 bool "Generate readable assembler code"
367 depends on DEBUG_KERNEL
370 Disable some compiler optimizations that tend to generate human unreadable
371 assembler output. This may make the kernel slightly slower, but it helps
372 to keep kernel developers who have to stare a lot at assembler listings
375 config HEADERS_INSTALL
376 bool "Install uapi headers to usr/include"
379 This option will install uapi headers (headers exported to user-space)
380 into the usr/include directory for use during the kernel build.
381 This is unneeded for building the kernel itself, but needed for some
382 user-space program samples. It is also needed by some features such
383 as uapi header sanity checks.
385 config DEBUG_SECTION_MISMATCH
386 bool "Enable full Section mismatch analysis"
389 The section mismatch analysis checks if there are illegal
390 references from one section to another section.
391 During linktime or runtime, some sections are dropped;
392 any use of code/data previously in these sections would
393 most likely result in an oops.
394 In the code, functions and variables are annotated with
395 __init,, etc. (see the full list in include/linux/init.h),
396 which results in the code/data being placed in specific sections.
397 The section mismatch analysis is always performed after a full
398 kernel build, and enabling this option causes the following
399 additional step to occur:
400 - Add the option -fno-inline-functions-called-once to gcc commands.
401 When inlining a function annotated with __init in a non-init
402 function, we would lose the section information and thus
403 the analysis would not catch the illegal reference.
404 This option tells gcc to inline less (but it does result in
407 config SECTION_MISMATCH_WARN_ONLY
408 bool "Make section mismatch errors non-fatal"
411 If you say N here, the build process will fail if there are any
412 section mismatch, instead of just throwing warnings.
416 config DEBUG_FORCE_FUNCTION_ALIGN_64B
417 bool "Force all function address 64B aligned" if EXPERT
419 There are cases that a commit from one domain changes the function
420 address alignment of other domains, and cause magic performance
421 bump (regression or improvement). Enable this option will help to
422 verify if the bump is caused by function alignment changes, while
423 it will slightly increase the kernel size and affect icache usage.
425 It is mainly for debug and performance tuning use.
428 # Select this config option from the architecture Kconfig, if it
429 # is preferred to always offer frame pointers as a config
430 # option on the architecture (regardless of KERNEL_DEBUG):
432 config ARCH_WANT_FRAME_POINTERS
436 bool "Compile the kernel with frame pointers"
437 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
438 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
440 If you say Y here the resulting kernel image will be slightly
441 larger and slower, but it gives very useful debugging information
442 in case of kernel bugs. (precise oopses/stacktraces/warnings)
444 config STACK_VALIDATION
445 bool "Compile-time stack metadata validation"
446 depends on HAVE_STACK_VALIDATION
449 Add compile-time checks to validate stack metadata, including frame
450 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
451 that runtime stack traces are more reliable.
453 This is also a prerequisite for generation of ORC unwind data, which
454 is needed for CONFIG_UNWINDER_ORC.
456 For more information, see
457 tools/objtool/Documentation/stack-validation.txt.
459 config VMLINUX_VALIDATION
461 depends on STACK_VALIDATION && DEBUG_ENTRY && !PARAVIRT
465 bool "Generate vmlinux.map file when linking"
468 Selecting this option will pass "-Map=vmlinux.map" to ld
469 when linking vmlinux. That file can be useful for verifying
470 and debugging magic section games, and for seeing which
471 pieces of code get eliminated with
472 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
474 config DEBUG_FORCE_WEAK_PER_CPU
475 bool "Force weak per-cpu definitions"
476 depends on DEBUG_KERNEL
478 s390 and alpha require percpu variables in modules to be
479 defined weak to work around addressing range issue which
480 puts the following two restrictions on percpu variable
483 1. percpu symbols must be unique whether static or not
484 2. percpu variables can't be defined inside a function
486 To ensure that generic code follows the above rules, this
487 option forces all percpu variables to be defined as weak.
489 endmenu # "Compiler options"
491 menu "Generic Kernel Debugging Instruments"
494 bool "Magic SysRq key"
497 If you say Y here, you will have some control over the system even
498 if the system crashes for example during kernel debugging (e.g., you
499 will be able to flush the buffer cache to disk, reboot the system
500 immediately or dump some status information). This is accomplished
501 by pressing various keys while holding SysRq (Alt+PrintScreen). It
502 also works on a serial console (on PC hardware at least), if you
503 send a BREAK and then within 5 seconds a command keypress. The
504 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
505 Don't say Y unless you really know what this hack does.
507 config MAGIC_SYSRQ_DEFAULT_ENABLE
508 hex "Enable magic SysRq key functions by default"
509 depends on MAGIC_SYSRQ
512 Specifies which SysRq key functions are enabled by default.
513 This may be set to 1 or 0 to enable or disable them all, or
514 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
516 config MAGIC_SYSRQ_SERIAL
517 bool "Enable magic SysRq key over serial"
518 depends on MAGIC_SYSRQ
521 Many embedded boards have a disconnected TTL level serial which can
522 generate some garbage that can lead to spurious false sysrq detects.
523 This option allows you to decide whether you want to enable the
526 config MAGIC_SYSRQ_SERIAL_SEQUENCE
527 string "Char sequence that enables magic SysRq over serial"
528 depends on MAGIC_SYSRQ_SERIAL
531 Specifies a sequence of characters that can follow BREAK to enable
532 SysRq on a serial console.
534 If unsure, leave an empty string and the option will not be enabled.
537 bool "Debug Filesystem"
539 debugfs is a virtual file system that kernel developers use to put
540 debugging files into. Enable this option to be able to read and
541 write to these files.
543 For detailed documentation on the debugfs API, see
544 Documentation/filesystems/.
549 prompt "Debugfs default access"
551 default DEBUG_FS_ALLOW_ALL
553 This selects the default access restrictions for debugfs.
554 It can be overridden with kernel command line option
555 debugfs=[on,no-mount,off]. The restrictions apply for API access
556 and filesystem registration.
558 config DEBUG_FS_ALLOW_ALL
561 No restrictions apply. Both API and filesystem registration
562 is on. This is the normal default operation.
564 config DEBUG_FS_DISALLOW_MOUNT
565 bool "Do not register debugfs as filesystem"
567 The API is open but filesystem is not loaded. Clients can still do
568 their work and read with debug tools that do not need
571 config DEBUG_FS_ALLOW_NONE
574 Access is off. Clients get -PERM when trying to create nodes in
575 debugfs tree and debugfs is not registered as a filesystem.
576 Client can then back-off or continue without debugfs access.
580 source "lib/Kconfig.kgdb"
581 source "lib/Kconfig.ubsan"
582 source "lib/Kconfig.kcsan"
587 bool "Kernel debugging"
589 Say Y here if you are developing drivers or trying to debug and
590 identify kernel problems.
593 bool "Miscellaneous debug code"
595 depends on DEBUG_KERNEL
597 Say Y here if you need to enable miscellaneous debug code that should
598 be under a more specific debug option but isn't.
601 menu "Memory Debugging"
603 source "mm/Kconfig.debug"
606 bool "Debug object operations"
607 depends on DEBUG_KERNEL
609 If you say Y here, additional code will be inserted into the
610 kernel to track the life time of various objects and validate
611 the operations on those objects.
613 config DEBUG_OBJECTS_SELFTEST
614 bool "Debug objects selftest"
615 depends on DEBUG_OBJECTS
617 This enables the selftest of the object debug code.
619 config DEBUG_OBJECTS_FREE
620 bool "Debug objects in freed memory"
621 depends on DEBUG_OBJECTS
623 This enables checks whether a k/v free operation frees an area
624 which contains an object which has not been deactivated
625 properly. This can make kmalloc/kfree-intensive workloads
628 config DEBUG_OBJECTS_TIMERS
629 bool "Debug timer objects"
630 depends on DEBUG_OBJECTS
632 If you say Y here, additional code will be inserted into the
633 timer routines to track the life time of timer objects and
634 validate the timer operations.
636 config DEBUG_OBJECTS_WORK
637 bool "Debug work objects"
638 depends on DEBUG_OBJECTS
640 If you say Y here, additional code will be inserted into the
641 work queue routines to track the life time of work objects and
642 validate the work operations.
644 config DEBUG_OBJECTS_RCU_HEAD
645 bool "Debug RCU callbacks objects"
646 depends on DEBUG_OBJECTS
648 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
650 config DEBUG_OBJECTS_PERCPU_COUNTER
651 bool "Debug percpu counter objects"
652 depends on DEBUG_OBJECTS
654 If you say Y here, additional code will be inserted into the
655 percpu counter routines to track the life time of percpu counter
656 objects and validate the percpu counter operations.
658 config DEBUG_OBJECTS_ENABLE_DEFAULT
659 int "debug_objects bootup default value (0-1)"
662 depends on DEBUG_OBJECTS
664 Debug objects boot parameter default value
667 bool "Debug slab memory allocations"
668 depends on DEBUG_KERNEL && SLAB
670 Say Y here to have the kernel do limited verification on memory
671 allocation as well as poisoning memory on free to catch use of freed
672 memory. This can make kmalloc/kfree-intensive workloads much slower.
675 bool "SLUB debugging on by default"
676 depends on SLUB && SLUB_DEBUG
679 Boot with debugging on by default. SLUB boots by default with
680 the runtime debug capabilities switched off. Enabling this is
681 equivalent to specifying the "slub_debug" parameter on boot.
682 There is no support for more fine grained debug control like
683 possible with slub_debug=xxx. SLUB debugging may be switched
684 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
689 bool "Enable SLUB performance statistics"
690 depends on SLUB && SYSFS
692 SLUB statistics are useful to debug SLUBs allocation behavior in
693 order find ways to optimize the allocator. This should never be
694 enabled for production use since keeping statistics slows down
695 the allocator by a few percentage points. The slabinfo command
696 supports the determination of the most active slabs to figure
697 out which slabs are relevant to a particular load.
698 Try running: slabinfo -DA
700 config HAVE_DEBUG_KMEMLEAK
703 config DEBUG_KMEMLEAK
704 bool "Kernel memory leak detector"
705 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
707 select STACKTRACE if STACKTRACE_SUPPORT
711 Say Y here if you want to enable the memory leak
712 detector. The memory allocation/freeing is traced in a way
713 similar to the Boehm's conservative garbage collector, the
714 difference being that the orphan objects are not freed but
715 only shown in /sys/kernel/debug/kmemleak. Enabling this
716 feature will introduce an overhead to memory
717 allocations. See Documentation/dev-tools/kmemleak.rst for more
720 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
721 of finding leaks due to the slab objects poisoning.
723 In order to access the kmemleak file, debugfs needs to be
724 mounted (usually at /sys/kernel/debug).
726 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
727 int "Kmemleak memory pool size"
728 depends on DEBUG_KMEMLEAK
732 Kmemleak must track all the memory allocations to avoid
733 reporting false positives. Since memory may be allocated or
734 freed before kmemleak is fully initialised, use a static pool
735 of metadata objects to track such callbacks. After kmemleak is
736 fully initialised, this memory pool acts as an emergency one
737 if slab allocations fail.
739 config DEBUG_KMEMLEAK_TEST
740 tristate "Simple test for the kernel memory leak detector"
741 depends on DEBUG_KMEMLEAK && m
743 This option enables a module that explicitly leaks memory.
747 config DEBUG_KMEMLEAK_DEFAULT_OFF
748 bool "Default kmemleak to off"
749 depends on DEBUG_KMEMLEAK
751 Say Y here to disable kmemleak by default. It can then be enabled
752 on the command line via kmemleak=on.
754 config DEBUG_KMEMLEAK_AUTO_SCAN
755 bool "Enable kmemleak auto scan thread on boot up"
757 depends on DEBUG_KMEMLEAK
759 Depending on the cpu, kmemleak scan may be cpu intensive and can
760 stall user tasks at times. This option enables/disables automatic
761 kmemleak scan at boot up.
763 Say N here to disable kmemleak auto scan thread to stop automatic
764 scanning. Disabling this option disables automatic reporting of
769 config DEBUG_STACK_USAGE
770 bool "Stack utilization instrumentation"
771 depends on DEBUG_KERNEL && !IA64
773 Enables the display of the minimum amount of free stack which each
774 task has ever had available in the sysrq-T and sysrq-P debug output.
776 This option will slow down process creation somewhat.
778 config SCHED_STACK_END_CHECK
779 bool "Detect stack corruption on calls to schedule()"
780 depends on DEBUG_KERNEL
783 This option checks for a stack overrun on calls to schedule().
784 If the stack end location is found to be over written always panic as
785 the content of the corrupted region can no longer be trusted.
786 This is to ensure no erroneous behaviour occurs which could result in
787 data corruption or a sporadic crash at a later stage once the region
788 is examined. The runtime overhead introduced is minimal.
790 config ARCH_HAS_DEBUG_VM_PGTABLE
793 An architecture should select this when it can successfully
794 build and run DEBUG_VM_PGTABLE.
798 depends on DEBUG_KERNEL
800 Enable this to turn on extended checks in the virtual-memory system
801 that may impact performance.
805 config DEBUG_VM_VMACACHE
806 bool "Debug VMA caching"
809 Enable this to turn on VMA caching debug information. Doing so
810 can cause significant overhead, so only enable it in non-production
816 bool "Debug VM red-black trees"
819 Enable VM red-black tree debugging information and extra validations.
823 config DEBUG_VM_PGFLAGS
824 bool "Debug page-flags operations"
827 Enables extra validation on page flags operations.
831 config DEBUG_VM_PGTABLE
832 bool "Debug arch page table for semantics compliance"
834 depends on ARCH_HAS_DEBUG_VM_PGTABLE
835 default y if DEBUG_VM
837 This option provides a debug method which can be used to test
838 architecture page table helper functions on various platforms in
839 verifying if they comply with expected generic MM semantics. This
840 will help architecture code in making sure that any changes or
841 new additions of these helpers still conform to expected
842 semantics of the generic MM. Platforms will have to opt in for
843 this through ARCH_HAS_DEBUG_VM_PGTABLE.
847 config ARCH_HAS_DEBUG_VIRTUAL
851 bool "Debug VM translations"
852 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
854 Enable some costly sanity checks in virtual to page code. This can
855 catch mistakes with virt_to_page() and friends.
859 config DEBUG_NOMMU_REGIONS
860 bool "Debug the global anon/private NOMMU mapping region tree"
861 depends on DEBUG_KERNEL && !MMU
863 This option causes the global tree of anonymous and private mapping
864 regions to be regularly checked for invalid topology.
866 config DEBUG_MEMORY_INIT
867 bool "Debug memory initialisation" if EXPERT
870 Enable this for additional checks during memory initialisation.
871 The sanity checks verify aspects of the VM such as the memory model
872 and other information provided by the architecture. Verbose
873 information will be printed at KERN_DEBUG loglevel depending
874 on the mminit_loglevel= command-line option.
878 config MEMORY_NOTIFIER_ERROR_INJECT
879 tristate "Memory hotplug notifier error injection module"
880 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
882 This option provides the ability to inject artificial errors to
883 memory hotplug notifier chain callbacks. It is controlled through
884 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
886 If the notifier call chain should be failed with some events
887 notified, write the error code to "actions/<notifier event>/error".
889 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
891 # cd /sys/kernel/debug/notifier-error-inject/memory
892 # echo -12 > actions/MEM_GOING_OFFLINE/error
893 # echo offline > /sys/devices/system/memory/memoryXXX/state
894 bash: echo: write error: Cannot allocate memory
896 To compile this code as a module, choose M here: the module will
897 be called memory-notifier-error-inject.
901 config DEBUG_PER_CPU_MAPS
902 bool "Debug access to per_cpu maps"
903 depends on DEBUG_KERNEL
906 Say Y to verify that the per_cpu map being accessed has
907 been set up. This adds a fair amount of code to kernel memory
908 and decreases performance.
912 config DEBUG_KMAP_LOCAL
913 bool "Debug kmap_local temporary mappings"
914 depends on DEBUG_KERNEL && KMAP_LOCAL
916 This option enables additional error checking for the kmap_local
917 infrastructure. Disable for production use.
919 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
922 config DEBUG_KMAP_LOCAL_FORCE_MAP
923 bool "Enforce kmap_local temporary mappings"
924 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
926 select DEBUG_KMAP_LOCAL
928 This option enforces temporary mappings through the kmap_local
929 mechanism for non-highmem pages and on non-highmem systems.
930 Disable this for production systems!
933 bool "Highmem debugging"
934 depends on DEBUG_KERNEL && HIGHMEM
935 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
936 select DEBUG_KMAP_LOCAL
938 This option enables additional error checking for high memory
939 systems. Disable for production systems.
941 config HAVE_DEBUG_STACKOVERFLOW
944 config DEBUG_STACKOVERFLOW
945 bool "Check for stack overflows"
946 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
948 Say Y here if you want to check for overflows of kernel, IRQ
949 and exception stacks (if your architecture uses them). This
950 option will show detailed messages if free stack space drops
951 below a certain limit.
953 These kinds of bugs usually occur when call-chains in the
954 kernel get too deep, especially when interrupts are
957 Use this in cases where you see apparently random memory
958 corruption, especially if it appears in 'struct thread_info'
960 If in doubt, say "N".
962 source "lib/Kconfig.kasan"
963 source "lib/Kconfig.kfence"
965 endmenu # "Memory Debugging"
968 bool "Debug shared IRQ handlers"
969 depends on DEBUG_KERNEL
971 Enable this to generate a spurious interrupt just before a shared
972 interrupt handler is deregistered (generating one when registering
973 is currently disabled). Drivers need to handle this correctly. Some
974 don't and need to be caught.
976 menu "Debug Oops, Lockups and Hangs"
981 Say Y here to enable the kernel to panic when it oopses. This
982 has the same effect as setting oops=panic on the kernel command
985 This feature is useful to ensure that the kernel does not do
986 anything erroneous after an oops which could result in data
987 corruption or other issues.
991 config PANIC_ON_OOPS_VALUE
994 default 0 if !PANIC_ON_OOPS
995 default 1 if PANIC_ON_OOPS
1001 Set the timeout value (in seconds) until a reboot occurs when
1002 the kernel panics. If n = 0, then we wait forever. A timeout
1003 value n > 0 will wait n seconds before rebooting, while a timeout
1004 value n < 0 will reboot immediately.
1006 config LOCKUP_DETECTOR
1009 config SOFTLOCKUP_DETECTOR
1010 bool "Detect Soft Lockups"
1011 depends on DEBUG_KERNEL && !S390
1012 select LOCKUP_DETECTOR
1014 Say Y here to enable the kernel to act as a watchdog to detect
1017 Softlockups are bugs that cause the kernel to loop in kernel
1018 mode for more than 20 seconds, without giving other tasks a
1019 chance to run. The current stack trace is displayed upon
1020 detection and the system will stay locked up.
1022 config BOOTPARAM_SOFTLOCKUP_PANIC
1023 bool "Panic (Reboot) On Soft Lockups"
1024 depends on SOFTLOCKUP_DETECTOR
1026 Say Y here to enable the kernel to panic on "soft lockups",
1027 which are bugs that cause the kernel to loop in kernel
1028 mode for more than 20 seconds (configurable using the watchdog_thresh
1029 sysctl), without giving other tasks a chance to run.
1031 The panic can be used in combination with panic_timeout,
1032 to cause the system to reboot automatically after a
1033 lockup has been detected. This feature is useful for
1034 high-availability systems that have uptime guarantees and
1035 where a lockup must be resolved ASAP.
1039 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
1041 depends on SOFTLOCKUP_DETECTOR
1043 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
1044 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
1046 config HARDLOCKUP_DETECTOR_PERF
1048 select SOFTLOCKUP_DETECTOR
1051 # Enables a timestamp based low pass filter to compensate for perf based
1052 # hard lockup detection which runs too fast due to turbo modes.
1054 config HARDLOCKUP_CHECK_TIMESTAMP
1058 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1059 # lockup detector rather than the perf based detector.
1061 config HARDLOCKUP_DETECTOR
1062 bool "Detect Hard Lockups"
1063 depends on DEBUG_KERNEL && !S390
1064 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1065 select LOCKUP_DETECTOR
1066 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1068 Say Y here to enable the kernel to act as a watchdog to detect
1071 Hardlockups are bugs that cause the CPU to loop in kernel mode
1072 for more than 10 seconds, without letting other interrupts have a
1073 chance to run. The current stack trace is displayed upon detection
1074 and the system will stay locked up.
1076 config BOOTPARAM_HARDLOCKUP_PANIC
1077 bool "Panic (Reboot) On Hard Lockups"
1078 depends on HARDLOCKUP_DETECTOR
1080 Say Y here to enable the kernel to panic on "hard lockups",
1081 which are bugs that cause the kernel to loop in kernel
1082 mode with interrupts disabled for more than 10 seconds (configurable
1083 using the watchdog_thresh sysctl).
1087 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
1089 depends on HARDLOCKUP_DETECTOR
1091 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
1092 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
1094 config DETECT_HUNG_TASK
1095 bool "Detect Hung Tasks"
1096 depends on DEBUG_KERNEL
1097 default SOFTLOCKUP_DETECTOR
1099 Say Y here to enable the kernel to detect "hung tasks",
1100 which are bugs that cause the task to be stuck in
1101 uninterruptible "D" state indefinitely.
1103 When a hung task is detected, the kernel will print the
1104 current stack trace (which you should report), but the
1105 task will stay in uninterruptible state. If lockdep is
1106 enabled then all held locks will also be reported. This
1107 feature has negligible overhead.
1109 config DEFAULT_HUNG_TASK_TIMEOUT
1110 int "Default timeout for hung task detection (in seconds)"
1111 depends on DETECT_HUNG_TASK
1114 This option controls the default timeout (in seconds) used
1115 to determine when a task has become non-responsive and should
1118 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1119 sysctl or by writing a value to
1120 /proc/sys/kernel/hung_task_timeout_secs.
1122 A timeout of 0 disables the check. The default is two minutes.
1123 Keeping the default should be fine in most cases.
1125 config BOOTPARAM_HUNG_TASK_PANIC
1126 bool "Panic (Reboot) On Hung Tasks"
1127 depends on DETECT_HUNG_TASK
1129 Say Y here to enable the kernel to panic on "hung tasks",
1130 which are bugs that cause the kernel to leave a task stuck
1131 in uninterruptible "D" state.
1133 The panic can be used in combination with panic_timeout,
1134 to cause the system to reboot automatically after a
1135 hung task has been detected. This feature is useful for
1136 high-availability systems that have uptime guarantees and
1137 where a hung tasks must be resolved ASAP.
1141 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
1143 depends on DETECT_HUNG_TASK
1145 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
1146 default 1 if BOOTPARAM_HUNG_TASK_PANIC
1149 bool "Detect Workqueue Stalls"
1150 depends on DEBUG_KERNEL
1152 Say Y here to enable stall detection on workqueues. If a
1153 worker pool doesn't make forward progress on a pending work
1154 item for over a given amount of time, 30s by default, a
1155 warning message is printed along with dump of workqueue
1156 state. This can be configured through kernel parameter
1157 "workqueue.watchdog_thresh" and its sysfs counterpart.
1160 tristate "Test module to generate lockups"
1163 This builds the "test_lockup" module that helps to make sure
1164 that watchdogs and lockup detectors are working properly.
1166 Depending on module parameters it could emulate soft or hard
1167 lockup, "hung task", or locking arbitrary lock for a long time.
1168 Also it could generate series of lockups with cooling-down periods.
1172 endmenu # "Debug lockups and hangs"
1174 menu "Scheduler Debugging"
1177 bool "Collect scheduler debugging info"
1178 depends on DEBUG_KERNEL && PROC_FS
1181 If you say Y here, the /proc/sched_debug file will be provided
1182 that can help debug the scheduler. The runtime overhead of this
1190 bool "Collect scheduler statistics"
1191 depends on DEBUG_KERNEL && PROC_FS
1194 If you say Y here, additional code will be inserted into the
1195 scheduler and related routines to collect statistics about
1196 scheduler behavior and provide them in /proc/schedstat. These
1197 stats may be useful for both tuning and debugging the scheduler
1198 If you aren't debugging the scheduler or trying to tune a specific
1199 application, you can say N to avoid the very slight overhead
1204 config DEBUG_TIMEKEEPING
1205 bool "Enable extra timekeeping sanity checking"
1207 This option will enable additional timekeeping sanity checks
1208 which may be helpful when diagnosing issues where timekeeping
1209 problems are suspected.
1211 This may include checks in the timekeeping hotpaths, so this
1212 option may have a (very small) performance impact to some
1217 config DEBUG_PREEMPT
1218 bool "Debug preemptible kernel"
1219 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1222 If you say Y here then the kernel will use a debug variant of the
1223 commonly used smp_processor_id() function and will print warnings
1224 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1225 will detect preemption count underflows.
1227 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1229 config LOCK_DEBUGGING_SUPPORT
1231 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1234 config PROVE_LOCKING
1235 bool "Lock debugging: prove locking correctness"
1236 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1238 select DEBUG_SPINLOCK
1239 select DEBUG_MUTEXES if !PREEMPT_RT
1240 select DEBUG_RT_MUTEXES if RT_MUTEXES
1242 select DEBUG_WW_MUTEX_SLOWPATH
1243 select DEBUG_LOCK_ALLOC
1244 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1245 select TRACE_IRQFLAGS
1248 This feature enables the kernel to prove that all locking
1249 that occurs in the kernel runtime is mathematically
1250 correct: that under no circumstance could an arbitrary (and
1251 not yet triggered) combination of observed locking
1252 sequences (on an arbitrary number of CPUs, running an
1253 arbitrary number of tasks and interrupt contexts) cause a
1256 In short, this feature enables the kernel to report locking
1257 related deadlocks before they actually occur.
1259 The proof does not depend on how hard and complex a
1260 deadlock scenario would be to trigger: how many
1261 participant CPUs, tasks and irq-contexts would be needed
1262 for it to trigger. The proof also does not depend on
1263 timing: if a race and a resulting deadlock is possible
1264 theoretically (no matter how unlikely the race scenario
1265 is), it will be proven so and will immediately be
1266 reported by the kernel (once the event is observed that
1267 makes the deadlock theoretically possible).
1269 If a deadlock is impossible (i.e. the locking rules, as
1270 observed by the kernel, are mathematically correct), the
1271 kernel reports nothing.
1273 NOTE: this feature can also be enabled for rwlocks, mutexes
1274 and rwsems - in which case all dependencies between these
1275 different locking variants are observed and mapped too, and
1276 the proof of observed correctness is also maintained for an
1277 arbitrary combination of these separate locking variants.
1279 For more details, see Documentation/locking/lockdep-design.rst.
1281 config PROVE_RAW_LOCK_NESTING
1282 bool "Enable raw_spinlock - spinlock nesting checks"
1283 depends on PROVE_LOCKING
1286 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1287 that the lock nesting rules for PREEMPT_RT enabled kernels are
1290 NOTE: There are known nesting problems. So if you enable this
1291 option expect lockdep splats until these problems have been fully
1292 addressed which is work in progress. This config switch allows to
1293 identify and analyze these problems. It will be removed and the
1294 check permanently enabled once the main issues have been fixed.
1296 If unsure, select N.
1299 bool "Lock usage statistics"
1300 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1302 select DEBUG_SPINLOCK
1303 select DEBUG_MUTEXES if !PREEMPT_RT
1304 select DEBUG_RT_MUTEXES if RT_MUTEXES
1305 select DEBUG_LOCK_ALLOC
1308 This feature enables tracking lock contention points
1310 For more details, see Documentation/locking/lockstat.rst
1312 This also enables lock events required by "perf lock",
1314 If you want to use "perf lock", you also need to turn on
1315 CONFIG_EVENT_TRACING.
1317 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1318 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1320 config DEBUG_RT_MUTEXES
1321 bool "RT Mutex debugging, deadlock detection"
1322 depends on DEBUG_KERNEL && RT_MUTEXES
1324 This allows rt mutex semantics violations and rt mutex related
1325 deadlocks (lockups) to be detected and reported automatically.
1327 config DEBUG_SPINLOCK
1328 bool "Spinlock and rw-lock debugging: basic checks"
1329 depends on DEBUG_KERNEL
1330 select UNINLINE_SPIN_UNLOCK
1332 Say Y here and build SMP to catch missing spinlock initialization
1333 and certain other kinds of spinlock errors commonly made. This is
1334 best used in conjunction with the NMI watchdog so that spinlock
1335 deadlocks are also debuggable.
1337 config DEBUG_MUTEXES
1338 bool "Mutex debugging: basic checks"
1339 depends on DEBUG_KERNEL && !PREEMPT_RT
1341 This feature allows mutex semantics violations to be detected and
1344 config DEBUG_WW_MUTEX_SLOWPATH
1345 bool "Wait/wound mutex debugging: Slowpath testing"
1346 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1347 select DEBUG_LOCK_ALLOC
1348 select DEBUG_SPINLOCK
1349 select DEBUG_MUTEXES if !PREEMPT_RT
1350 select DEBUG_RT_MUTEXES if PREEMPT_RT
1352 This feature enables slowpath testing for w/w mutex users by
1353 injecting additional -EDEADLK wound/backoff cases. Together with
1354 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1355 will test all possible w/w mutex interface abuse with the
1356 exception of simply not acquiring all the required locks.
1357 Note that this feature can introduce significant overhead, so
1358 it really should not be enabled in a production or distro kernel,
1359 even a debug kernel. If you are a driver writer, enable it. If
1360 you are a distro, do not.
1363 bool "RW Semaphore debugging: basic checks"
1364 depends on DEBUG_KERNEL
1366 This debugging feature allows mismatched rw semaphore locks
1367 and unlocks to be detected and reported.
1369 config DEBUG_LOCK_ALLOC
1370 bool "Lock debugging: detect incorrect freeing of live locks"
1371 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1372 select DEBUG_SPINLOCK
1373 select DEBUG_MUTEXES if !PREEMPT_RT
1374 select DEBUG_RT_MUTEXES if RT_MUTEXES
1377 This feature will check whether any held lock (spinlock, rwlock,
1378 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1379 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1380 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1381 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1382 held during task exit.
1386 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1391 config LOCKDEP_SMALL
1395 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1396 depends on LOCKDEP && !LOCKDEP_SMALL
1400 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1402 config LOCKDEP_CHAINS_BITS
1403 int "Bitsize for MAX_LOCKDEP_CHAINS"
1404 depends on LOCKDEP && !LOCKDEP_SMALL
1408 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1410 config LOCKDEP_STACK_TRACE_BITS
1411 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1412 depends on LOCKDEP && !LOCKDEP_SMALL
1416 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1418 config LOCKDEP_STACK_TRACE_HASH_BITS
1419 int "Bitsize for STACK_TRACE_HASH_SIZE"
1420 depends on LOCKDEP && !LOCKDEP_SMALL
1424 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1426 config LOCKDEP_CIRCULAR_QUEUE_BITS
1427 int "Bitsize for elements in circular_queue struct"
1432 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1434 config DEBUG_LOCKDEP
1435 bool "Lock dependency engine debugging"
1436 depends on DEBUG_KERNEL && LOCKDEP
1437 select DEBUG_IRQFLAGS
1439 If you say Y here, the lock dependency engine will do
1440 additional runtime checks to debug itself, at the price
1441 of more runtime overhead.
1443 config DEBUG_ATOMIC_SLEEP
1444 bool "Sleep inside atomic section checking"
1445 select PREEMPT_COUNT
1446 depends on DEBUG_KERNEL
1447 depends on !ARCH_NO_PREEMPT
1449 If you say Y here, various routines which may sleep will become very
1450 noisy if they are called inside atomic sections: when a spinlock is
1451 held, inside an rcu read side critical section, inside preempt disabled
1452 sections, inside an interrupt, etc...
1454 config DEBUG_LOCKING_API_SELFTESTS
1455 bool "Locking API boot-time self-tests"
1456 depends on DEBUG_KERNEL
1458 Say Y here if you want the kernel to run a short self-test during
1459 bootup. The self-test checks whether common types of locking bugs
1460 are detected by debugging mechanisms or not. (if you disable
1461 lock debugging then those bugs won't be detected of course.)
1462 The following locking APIs are covered: spinlocks, rwlocks,
1465 config LOCK_TORTURE_TEST
1466 tristate "torture tests for locking"
1467 depends on DEBUG_KERNEL
1470 This option provides a kernel module that runs torture tests
1471 on kernel locking primitives. The kernel module may be built
1472 after the fact on the running kernel to be tested, if desired.
1474 Say Y here if you want kernel locking-primitive torture tests
1475 to be built into the kernel.
1476 Say M if you want these torture tests to build as a module.
1477 Say N if you are unsure.
1479 config WW_MUTEX_SELFTEST
1480 tristate "Wait/wound mutex selftests"
1482 This option provides a kernel module that runs tests on the
1483 on the struct ww_mutex locking API.
1485 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1486 with this test harness.
1488 Say M if you want these self tests to build as a module.
1489 Say N if you are unsure.
1491 config SCF_TORTURE_TEST
1492 tristate "torture tests for smp_call_function*()"
1493 depends on DEBUG_KERNEL
1496 This option provides a kernel module that runs torture tests
1497 on the smp_call_function() family of primitives. The kernel
1498 module may be built after the fact on the running kernel to
1499 be tested, if desired.
1501 config CSD_LOCK_WAIT_DEBUG
1502 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1503 depends on DEBUG_KERNEL
1507 This option enables debug prints when CPUs are slow to respond
1508 to the smp_call_function*() IPI wrappers. These debug prints
1509 include the IPI handler function currently executing (if any)
1510 and relevant stack traces.
1512 endmenu # lock debugging
1514 config TRACE_IRQFLAGS
1515 depends on TRACE_IRQFLAGS_SUPPORT
1518 Enables hooks to interrupt enabling and disabling for
1519 either tracing or lock debugging.
1521 config TRACE_IRQFLAGS_NMI
1523 depends on TRACE_IRQFLAGS
1524 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1526 config DEBUG_IRQFLAGS
1527 bool "Debug IRQ flag manipulation"
1529 Enables checks for potentially unsafe enabling or disabling of
1530 interrupts, such as calling raw_local_irq_restore() when interrupts
1534 bool "Stack backtrace support"
1535 depends on STACKTRACE_SUPPORT
1537 This option causes the kernel to create a /proc/pid/stack for
1538 every process, showing its current stack trace.
1539 It is also used by various kernel debugging features that require
1540 stack trace generation.
1542 config WARN_ALL_UNSEEDED_RANDOM
1543 bool "Warn for all uses of unseeded randomness"
1546 Some parts of the kernel contain bugs relating to their use of
1547 cryptographically secure random numbers before it's actually possible
1548 to generate those numbers securely. This setting ensures that these
1549 flaws don't go unnoticed, by enabling a message, should this ever
1550 occur. This will allow people with obscure setups to know when things
1551 are going wrong, so that they might contact developers about fixing
1554 Unfortunately, on some models of some architectures getting
1555 a fully seeded CRNG is extremely difficult, and so this can
1556 result in dmesg getting spammed for a surprisingly long
1557 time. This is really bad from a security perspective, and
1558 so architecture maintainers really need to do what they can
1559 to get the CRNG seeded sooner after the system is booted.
1560 However, since users cannot do anything actionable to
1561 address this, by default the kernel will issue only a single
1562 warning for the first use of unseeded randomness.
1564 Say Y here if you want to receive warnings for all uses of
1565 unseeded randomness. This will be of use primarily for
1566 those developers interested in improving the security of
1567 Linux kernels running on their architecture (or
1570 config DEBUG_KOBJECT
1571 bool "kobject debugging"
1572 depends on DEBUG_KERNEL
1574 If you say Y here, some extra kobject debugging messages will be sent
1577 config DEBUG_KOBJECT_RELEASE
1578 bool "kobject release debugging"
1579 depends on DEBUG_OBJECTS_TIMERS
1581 kobjects are reference counted objects. This means that their
1582 last reference count put is not predictable, and the kobject can
1583 live on past the point at which a driver decides to drop it's
1584 initial reference to the kobject gained on allocation. An
1585 example of this would be a struct device which has just been
1588 However, some buggy drivers assume that after such an operation,
1589 the memory backing the kobject can be immediately freed. This
1590 goes completely against the principles of a refcounted object.
1592 If you say Y here, the kernel will delay the release of kobjects
1593 on the last reference count to improve the visibility of this
1594 kind of kobject release bug.
1596 config HAVE_DEBUG_BUGVERBOSE
1599 menu "Debug kernel data structures"
1602 bool "Debug linked list manipulation"
1603 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1605 Enable this to turn on extended checks in the linked-list
1611 bool "Debug priority linked list manipulation"
1612 depends on DEBUG_KERNEL
1614 Enable this to turn on extended checks in the priority-ordered
1615 linked-list (plist) walking routines. This checks the entire
1616 list multiple times during each manipulation.
1621 bool "Debug SG table operations"
1622 depends on DEBUG_KERNEL
1624 Enable this to turn on checks on scatter-gather tables. This can
1625 help find problems with drivers that do not properly initialize
1630 config DEBUG_NOTIFIERS
1631 bool "Debug notifier call chains"
1632 depends on DEBUG_KERNEL
1634 Enable this to turn on sanity checking for notifier call chains.
1635 This is most useful for kernel developers to make sure that
1636 modules properly unregister themselves from notifier chains.
1637 This is a relatively cheap check but if you care about maximum
1640 config BUG_ON_DATA_CORRUPTION
1641 bool "Trigger a BUG when data corruption is detected"
1644 Select this option if the kernel should BUG when it encounters
1645 data corruption in kernel memory structures when they get checked
1652 config DEBUG_CREDENTIALS
1653 bool "Debug credential management"
1654 depends on DEBUG_KERNEL
1656 Enable this to turn on some debug checking for credential
1657 management. The additional code keeps track of the number of
1658 pointers from task_structs to any given cred struct, and checks to
1659 see that this number never exceeds the usage count of the cred
1662 Furthermore, if SELinux is enabled, this also checks that the
1663 security pointer in the cred struct is never seen to be invalid.
1667 source "kernel/rcu/Kconfig.debug"
1669 config DEBUG_WQ_FORCE_RR_CPU
1670 bool "Force round-robin CPU selection for unbound work items"
1671 depends on DEBUG_KERNEL
1674 Workqueue used to implicitly guarantee that work items queued
1675 without explicit CPU specified are put on the local CPU. This
1676 guarantee is no longer true and while local CPU is still
1677 preferred work items may be put on foreign CPUs. Kernel
1678 parameter "workqueue.debug_force_rr_cpu" is added to force
1679 round-robin CPU selection to flush out usages which depend on the
1680 now broken guarantee. This config option enables the debug
1681 feature by default. When enabled, memory and cache locality will
1684 config CPU_HOTPLUG_STATE_CONTROL
1685 bool "Enable CPU hotplug state control"
1686 depends on DEBUG_KERNEL
1687 depends on HOTPLUG_CPU
1690 Allows to write steps between "offline" and "online" to the CPUs
1691 sysfs target file so states can be stepped granular. This is a debug
1692 option for now as the hotplug machinery cannot be stopped and
1693 restarted at arbitrary points yet.
1695 Say N if your are unsure.
1698 bool "Latency measuring infrastructure"
1699 depends on DEBUG_KERNEL
1700 depends on STACKTRACE_SUPPORT
1702 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1708 Enable this option if you want to use the LatencyTOP tool
1709 to find out which userspace is blocking on what kernel operations.
1711 source "kernel/trace/Kconfig"
1713 config PROVIDE_OHCI1394_DMA_INIT
1714 bool "Remote debugging over FireWire early on boot"
1715 depends on PCI && X86
1717 If you want to debug problems which hang or crash the kernel early
1718 on boot and the crashing machine has a FireWire port, you can use
1719 this feature to remotely access the memory of the crashed machine
1720 over FireWire. This employs remote DMA as part of the OHCI1394
1721 specification which is now the standard for FireWire controllers.
1723 With remote DMA, you can monitor the printk buffer remotely using
1724 firescope and access all memory below 4GB using fireproxy from gdb.
1725 Even controlling a kernel debugger is possible using remote DMA.
1729 If ohci1394_dma=early is used as boot parameter, it will initialize
1730 all OHCI1394 controllers which are found in the PCI config space.
1732 As all changes to the FireWire bus such as enabling and disabling
1733 devices cause a bus reset and thereby disable remote DMA for all
1734 devices, be sure to have the cable plugged and FireWire enabled on
1735 the debugging host before booting the debug target for debugging.
1737 This code (~1k) is freed after boot. By then, the firewire stack
1738 in charge of the OHCI-1394 controllers should be used instead.
1740 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1742 source "samples/Kconfig"
1744 config ARCH_HAS_DEVMEM_IS_ALLOWED
1747 config STRICT_DEVMEM
1748 bool "Filter access to /dev/mem"
1749 depends on MMU && DEVMEM
1750 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1751 default y if PPC || X86 || ARM64
1753 If this option is disabled, you allow userspace (root) access to all
1754 of memory, including kernel and userspace memory. Accidental
1755 access to this is obviously disastrous, but specific access can
1756 be used by people debugging the kernel. Note that with PAT support
1757 enabled, even in this case there are restrictions on /dev/mem
1758 use due to the cache aliasing requirements.
1760 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1761 file only allows userspace access to PCI space and the BIOS code and
1762 data regions. This is sufficient for dosemu and X and all common
1767 config IO_STRICT_DEVMEM
1768 bool "Filter I/O access to /dev/mem"
1769 depends on STRICT_DEVMEM
1771 If this option is disabled, you allow userspace (root) access to all
1772 io-memory regardless of whether a driver is actively using that
1773 range. Accidental access to this is obviously disastrous, but
1774 specific access can be used by people debugging kernel drivers.
1776 If this option is switched on, the /dev/mem file only allows
1777 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1778 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1779 if the driver using a given range cannot be disabled.
1783 menu "$(SRCARCH) Debugging"
1785 source "arch/$(SRCARCH)/Kconfig.debug"
1789 menu "Kernel Testing and Coverage"
1791 source "lib/kunit/Kconfig"
1793 config NOTIFIER_ERROR_INJECTION
1794 tristate "Notifier error injection"
1795 depends on DEBUG_KERNEL
1798 This option provides the ability to inject artificial errors to
1799 specified notifier chain callbacks. It is useful to test the error
1800 handling of notifier call chain failures.
1804 config PM_NOTIFIER_ERROR_INJECT
1805 tristate "PM notifier error injection module"
1806 depends on PM && NOTIFIER_ERROR_INJECTION
1807 default m if PM_DEBUG
1809 This option provides the ability to inject artificial errors to
1810 PM notifier chain callbacks. It is controlled through debugfs
1811 interface /sys/kernel/debug/notifier-error-inject/pm
1813 If the notifier call chain should be failed with some events
1814 notified, write the error code to "actions/<notifier event>/error".
1816 Example: Inject PM suspend error (-12 = -ENOMEM)
1818 # cd /sys/kernel/debug/notifier-error-inject/pm/
1819 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1820 # echo mem > /sys/power/state
1821 bash: echo: write error: Cannot allocate memory
1823 To compile this code as a module, choose M here: the module will
1824 be called pm-notifier-error-inject.
1828 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1829 tristate "OF reconfig notifier error injection module"
1830 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1832 This option provides the ability to inject artificial errors to
1833 OF reconfig notifier chain callbacks. It is controlled
1834 through debugfs interface under
1835 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1837 If the notifier call chain should be failed with some events
1838 notified, write the error code to "actions/<notifier event>/error".
1840 To compile this code as a module, choose M here: the module will
1841 be called of-reconfig-notifier-error-inject.
1845 config NETDEV_NOTIFIER_ERROR_INJECT
1846 tristate "Netdev notifier error injection module"
1847 depends on NET && NOTIFIER_ERROR_INJECTION
1849 This option provides the ability to inject artificial errors to
1850 netdevice notifier chain callbacks. It is controlled through debugfs
1851 interface /sys/kernel/debug/notifier-error-inject/netdev
1853 If the notifier call chain should be failed with some events
1854 notified, write the error code to "actions/<notifier event>/error".
1856 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1858 # cd /sys/kernel/debug/notifier-error-inject/netdev
1859 # echo -22 > actions/NETDEV_CHANGEMTU/error
1860 # ip link set eth0 mtu 1024
1861 RTNETLINK answers: Invalid argument
1863 To compile this code as a module, choose M here: the module will
1864 be called netdev-notifier-error-inject.
1868 config FUNCTION_ERROR_INJECTION
1870 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1872 config FAULT_INJECTION
1873 bool "Fault-injection framework"
1874 depends on DEBUG_KERNEL
1876 Provide fault-injection framework.
1877 For more details, see Documentation/fault-injection/.
1880 bool "Fault-injection capability for kmalloc"
1881 depends on FAULT_INJECTION
1882 depends on SLAB || SLUB
1884 Provide fault-injection capability for kmalloc.
1886 config FAIL_PAGE_ALLOC
1887 bool "Fault-injection capability for alloc_pages()"
1888 depends on FAULT_INJECTION
1890 Provide fault-injection capability for alloc_pages().
1892 config FAULT_INJECTION_USERCOPY
1893 bool "Fault injection capability for usercopy functions"
1894 depends on FAULT_INJECTION
1896 Provides fault-injection capability to inject failures
1897 in usercopy functions (copy_from_user(), get_user(), ...).
1899 config FAIL_MAKE_REQUEST
1900 bool "Fault-injection capability for disk IO"
1901 depends on FAULT_INJECTION && BLOCK
1903 Provide fault-injection capability for disk IO.
1905 config FAIL_IO_TIMEOUT
1906 bool "Fault-injection capability for faking disk interrupts"
1907 depends on FAULT_INJECTION && BLOCK
1909 Provide fault-injection capability on end IO handling. This
1910 will make the block layer "forget" an interrupt as configured,
1911 thus exercising the error handling.
1913 Only works with drivers that use the generic timeout handling,
1914 for others it won't do anything.
1917 bool "Fault-injection capability for futexes"
1919 depends on FAULT_INJECTION && FUTEX
1921 Provide fault-injection capability for futexes.
1923 config FAULT_INJECTION_DEBUG_FS
1924 bool "Debugfs entries for fault-injection capabilities"
1925 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1927 Enable configuration of fault-injection capabilities via debugfs.
1929 config FAIL_FUNCTION
1930 bool "Fault-injection capability for functions"
1931 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1933 Provide function-based fault-injection capability.
1934 This will allow you to override a specific function with a return
1935 with given return value. As a result, function caller will see
1936 an error value and have to handle it. This is useful to test the
1937 error handling in various subsystems.
1939 config FAIL_MMC_REQUEST
1940 bool "Fault-injection capability for MMC IO"
1941 depends on FAULT_INJECTION_DEBUG_FS && MMC
1943 Provide fault-injection capability for MMC IO.
1944 This will make the mmc core return data errors. This is
1945 useful to test the error handling in the mmc block device
1946 and to test how the mmc host driver handles retries from
1950 bool "Fault-injection capability for SunRPC"
1951 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1953 Provide fault-injection capability for SunRPC and
1956 config FAULT_INJECTION_STACKTRACE_FILTER
1957 bool "stacktrace filter for fault-injection capabilities"
1958 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1961 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1963 Provide stacktrace filter for fault-injection capabilities
1965 config ARCH_HAS_KCOV
1968 An architecture should select this when it can successfully
1969 build and run with CONFIG_KCOV. This typically requires
1970 disabling instrumentation for some early boot code.
1972 config CC_HAS_SANCOV_TRACE_PC
1973 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1977 bool "Code coverage for fuzzing"
1978 depends on ARCH_HAS_KCOV
1979 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1981 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1983 KCOV exposes kernel code coverage information in a form suitable
1984 for coverage-guided fuzzing (randomized testing).
1986 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1987 different machines and across reboots. If you need stable PC values,
1988 disable RANDOMIZE_BASE.
1990 For more details, see Documentation/dev-tools/kcov.rst.
1992 config KCOV_ENABLE_COMPARISONS
1993 bool "Enable comparison operands collection by KCOV"
1995 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
1997 KCOV also exposes operands of every comparison in the instrumented
1998 code along with operand sizes and PCs of the comparison instructions.
1999 These operands can be used by fuzzing engines to improve the quality
2000 of fuzzing coverage.
2002 config KCOV_INSTRUMENT_ALL
2003 bool "Instrument all code by default"
2007 If you are doing generic system call fuzzing (like e.g. syzkaller),
2008 then you will want to instrument the whole kernel and you should
2009 say y here. If you are doing more targeted fuzzing (like e.g.
2010 filesystem fuzzing with AFL) then you will want to enable coverage
2011 for more specific subsets of files, and should say n here.
2013 config KCOV_IRQ_AREA_SIZE
2014 hex "Size of interrupt coverage collection area in words"
2018 KCOV uses preallocated per-cpu areas to collect coverage from
2019 soft interrupts. This specifies the size of those areas in the
2020 number of unsigned long words.
2022 menuconfig RUNTIME_TESTING_MENU
2023 bool "Runtime Testing"
2026 if RUNTIME_TESTING_MENU
2029 tristate "Linux Kernel Dump Test Tool Module"
2032 This module enables testing of the different dumping mechanisms by
2033 inducing system failures at predefined crash points.
2034 If you don't need it: say N
2035 Choose M here to compile this code as a module. The module will be
2038 Documentation on how to use the module can be found in
2039 Documentation/fault-injection/provoke-crashes.rst
2041 config TEST_LIST_SORT
2042 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2044 default KUNIT_ALL_TESTS
2046 Enable this to turn on 'list_sort()' function test. This test is
2047 executed only once during system boot (so affects only boot time),
2048 or at module load time.
2052 config TEST_MIN_HEAP
2053 tristate "Min heap test"
2054 depends on DEBUG_KERNEL || m
2056 Enable this to turn on min heap function tests. This test is
2057 executed only once during system boot (so affects only boot time),
2058 or at module load time.
2063 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2065 default KUNIT_ALL_TESTS
2067 This option enables the self-test function of 'sort()' at boot,
2068 or at module load time.
2073 tristate "64bit/32bit division and modulo test"
2074 depends on DEBUG_KERNEL || m
2076 Enable this to turn on 'do_div()' function test. This test is
2077 executed only once during system boot (so affects only boot time),
2078 or at module load time.
2082 config KPROBES_SANITY_TEST
2083 bool "Kprobes sanity tests"
2084 depends on DEBUG_KERNEL
2087 This option provides for testing basic kprobes functionality on
2088 boot. Samples of kprobe and kretprobe are inserted and
2089 verified for functionality.
2091 Say N if you are unsure.
2093 config BACKTRACE_SELF_TEST
2094 tristate "Self test for the backtrace code"
2095 depends on DEBUG_KERNEL
2097 This option provides a kernel module that can be used to test
2098 the kernel stack backtrace code. This option is not useful
2099 for distributions or general kernels, but only for kernel
2100 developers working on architecture code.
2102 Note that if you want to also test saved backtraces, you will
2103 have to enable STACKTRACE as well.
2105 Say N if you are unsure.
2108 tristate "Red-Black tree test"
2109 depends on DEBUG_KERNEL
2111 A benchmark measuring the performance of the rbtree library.
2112 Also includes rbtree invariant checks.
2114 config REED_SOLOMON_TEST
2115 tristate "Reed-Solomon library test"
2116 depends on DEBUG_KERNEL || m
2118 select REED_SOLOMON_ENC16
2119 select REED_SOLOMON_DEC16
2121 This option enables the self-test function of rslib at boot,
2122 or at module load time.
2126 config INTERVAL_TREE_TEST
2127 tristate "Interval tree test"
2128 depends on DEBUG_KERNEL
2129 select INTERVAL_TREE
2131 A benchmark measuring the performance of the interval tree library
2134 tristate "Per cpu operations test"
2135 depends on m && DEBUG_KERNEL
2137 Enable this option to build test module which validates per-cpu
2142 config ATOMIC64_SELFTEST
2143 tristate "Perform an atomic64_t self-test"
2145 Enable this option to test the atomic64_t functions at boot or
2146 at module load time.
2150 config ASYNC_RAID6_TEST
2151 tristate "Self test for hardware accelerated raid6 recovery"
2152 depends on ASYNC_RAID6_RECOV
2155 This is a one-shot self test that permutes through the
2156 recovery of all the possible two disk failure scenarios for a
2157 N-disk array. Recovery is performed with the asynchronous
2158 raid6 recovery routines, and will optionally use an offload
2159 engine if one is available.
2164 tristate "Test functions located in the hexdump module at runtime"
2166 config STRING_SELFTEST
2167 tristate "Test string functions at runtime"
2169 config TEST_STRING_HELPERS
2170 tristate "Test functions located in the string_helpers module at runtime"
2173 tristate "Test strscpy*() family of functions at runtime"
2176 tristate "Test kstrto*() family of functions at runtime"
2179 tristate "Test printf() family of functions at runtime"
2182 tristate "Test scanf() family of functions at runtime"
2185 tristate "Test bitmap_*() family of functions at runtime"
2187 Enable this option to test the bitmap functions at boot.
2192 tristate "Test functions located in the uuid module at runtime"
2195 tristate "Test the XArray code at runtime"
2197 config TEST_OVERFLOW
2198 tristate "Test check_*_overflow() functions at runtime"
2200 config TEST_RHASHTABLE
2201 tristate "Perform selftest on resizable hash table"
2203 Enable this option to test the rhashtable functions at boot.
2208 tristate "Perform selftest on hash functions"
2210 Enable this option to test the kernel's integer (<linux/hash.h>),
2211 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
2212 hash functions on boot (or module load).
2214 This is intended to help people writing architecture-specific
2215 optimized versions. If unsure, say N.
2218 tristate "Perform selftest on IDA functions"
2221 tristate "Perform selftest on priority array manager"
2224 Enable this option to test priority array manager on boot
2229 config TEST_IRQ_TIMINGS
2230 bool "IRQ timings selftest"
2231 depends on IRQ_TIMINGS
2233 Enable this option to test the irq timings code on boot.
2238 tristate "Test module loading with 'hello world' module"
2241 This builds the "test_module" module that emits "Hello, world"
2242 on printk when loaded. It is designed to be used for basic
2243 evaluation of the module loading subsystem (for example when
2244 validating module verification). It lacks any extra dependencies,
2245 and will not normally be loaded by the system unless explicitly
2251 tristate "Test module for compilation of bitops operations"
2254 This builds the "test_bitops" module that is much like the
2255 TEST_LKM module except that it does a basic exercise of the
2256 set/clear_bit macros and get_count_order/long to make sure there are
2257 no compiler warnings from C=1 sparse checker or -Wextra
2258 compilations. It has no dependencies and doesn't run or load unless
2259 explicitly requested by name. for example: modprobe test_bitops.
2264 tristate "Test module for stress/performance analysis of vmalloc allocator"
2269 This builds the "test_vmalloc" module that should be used for
2270 stress and performance analysis. So, any new change for vmalloc
2271 subsystem can be evaluated from performance and stability point
2276 config TEST_USER_COPY
2277 tristate "Test user/kernel boundary protections"
2280 This builds the "test_user_copy" module that runs sanity checks
2281 on the copy_to/from_user infrastructure, making sure basic
2282 user/kernel boundary testing is working. If it fails to load,
2283 a regression has been detected in the user/kernel memory boundary
2289 tristate "Test BPF filter functionality"
2292 This builds the "test_bpf" module that runs various test vectors
2293 against the BPF interpreter or BPF JIT compiler depending on the
2294 current setting. This is in particular useful for BPF JIT compiler
2295 development, but also to run regression tests against changes in
2296 the interpreter code. It also enables test stubs for eBPF maps and
2297 verifier used by user space verifier testsuite.
2301 config TEST_BLACKHOLE_DEV
2302 tristate "Test blackhole netdev functionality"
2305 This builds the "test_blackhole_dev" module that validates the
2306 data path through this blackhole netdev.
2310 config FIND_BIT_BENCHMARK
2311 tristate "Test find_bit functions"
2313 This builds the "test_find_bit" module that measure find_*_bit()
2314 functions performance.
2318 config TEST_FIRMWARE
2319 tristate "Test firmware loading via userspace interface"
2320 depends on FW_LOADER
2322 This builds the "test_firmware" module that creates a userspace
2323 interface for testing firmware loading. This can be used to
2324 control the triggering of firmware loading without needing an
2325 actual firmware-using device. The contents can be rechecked by
2331 tristate "sysctl test driver"
2332 depends on PROC_SYSCTL
2334 This builds the "test_sysctl" module. This driver enables to test the
2335 proc sysctl interfaces available to drivers safely without affecting
2336 production knobs which might alter system functionality.
2340 config BITFIELD_KUNIT
2341 tristate "KUnit test bitfield functions at runtime"
2344 Enable this option to test the bitfield functions at boot.
2346 KUnit tests run during boot and output the results to the debug log
2347 in TAP format (http://testanything.org/). Only useful for kernel devs
2348 running the KUnit test harness, and not intended for inclusion into a
2351 For more information on KUnit and unit tests in general please refer
2352 to the KUnit documentation in Documentation/dev-tools/kunit/.
2356 config RESOURCE_KUNIT_TEST
2357 tristate "KUnit test for resource API"
2360 This builds the resource API unit test.
2361 Tests the logic of API provided by resource.c and ioport.h.
2362 For more information on KUnit and unit tests in general please refer
2363 to the KUnit documentation in Documentation/dev-tools/kunit/.
2367 config SYSCTL_KUNIT_TEST
2368 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2370 default KUNIT_ALL_TESTS
2372 This builds the proc sysctl unit test, which runs on boot.
2373 Tests the API contract and implementation correctness of sysctl.
2374 For more information on KUnit and unit tests in general please refer
2375 to the KUnit documentation in Documentation/dev-tools/kunit/.
2379 config LIST_KUNIT_TEST
2380 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2382 default KUNIT_ALL_TESTS
2384 This builds the linked list KUnit test suite.
2385 It tests that the API and basic functionality of the list_head type
2386 and associated macros.
2388 KUnit tests run during boot and output the results to the debug log
2389 in TAP format (https://testanything.org/). Only useful for kernel devs
2390 running the KUnit test harness, and not intended for inclusion into a
2393 For more information on KUnit and unit tests in general please refer
2394 to the KUnit documentation in Documentation/dev-tools/kunit/.
2398 config LINEAR_RANGES_TEST
2399 tristate "KUnit test for linear_ranges"
2401 select LINEAR_RANGES
2403 This builds the linear_ranges unit test, which runs on boot.
2404 Tests the linear_ranges logic correctness.
2405 For more information on KUnit and unit tests in general please refer
2406 to the KUnit documentation in Documentation/dev-tools/kunit/.
2410 config CMDLINE_KUNIT_TEST
2411 tristate "KUnit test for cmdline API"
2414 This builds the cmdline API unit test.
2415 Tests the logic of API provided by cmdline.c.
2416 For more information on KUnit and unit tests in general please refer
2417 to the KUnit documentation in Documentation/dev-tools/kunit/.
2422 tristate "KUnit test for bits.h"
2425 This builds the bits unit test.
2426 Tests the logic of macros defined in bits.h.
2427 For more information on KUnit and unit tests in general please refer
2428 to the KUnit documentation in Documentation/dev-tools/kunit/.
2432 config SLUB_KUNIT_TEST
2433 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2434 depends on SLUB_DEBUG && KUNIT
2435 default KUNIT_ALL_TESTS
2437 This builds SLUB allocator unit test.
2438 Tests SLUB cache debugging functionality.
2439 For more information on KUnit and unit tests in general please refer
2440 to the KUnit documentation in Documentation/dev-tools/kunit/.
2444 config RATIONAL_KUNIT_TEST
2445 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2446 depends on KUNIT && RATIONAL
2447 default KUNIT_ALL_TESTS
2449 This builds the rational math unit test.
2450 For more information on KUnit and unit tests in general please refer
2451 to the KUnit documentation in Documentation/dev-tools/kunit/.
2456 tristate "udelay test driver"
2458 This builds the "udelay_test" module that helps to make sure
2459 that udelay() is working properly.
2463 config TEST_STATIC_KEYS
2464 tristate "Test static keys"
2467 Test the static key interfaces.
2472 tristate "kmod stress tester"
2474 depends on NETDEVICES && NET_CORE && INET # for TUN
2481 Test the kernel's module loading mechanism: kmod. kmod implements
2482 support to load modules using the Linux kernel's usermode helper.
2483 This test provides a series of tests against kmod.
2485 Although technically you can either build test_kmod as a module or
2486 into the kernel we disallow building it into the kernel since
2487 it stress tests request_module() and this will very likely cause
2488 some issues by taking over precious threads available from other
2489 module load requests, ultimately this could be fatal.
2493 tools/testing/selftests/kmod/kmod.sh --help
2497 config TEST_DEBUG_VIRTUAL
2498 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2499 depends on DEBUG_VIRTUAL
2501 Test the kernel's ability to detect incorrect calls to
2502 virt_to_phys() done against the non-linear part of the
2503 kernel's virtual address map.
2507 config TEST_MEMCAT_P
2508 tristate "Test memcat_p() helper function"
2510 Test the memcat_p() helper for correctly merging two
2511 pointer arrays together.
2515 config TEST_LIVEPATCH
2516 tristate "Test livepatching"
2518 depends on DYNAMIC_DEBUG
2519 depends on LIVEPATCH
2522 Test kernel livepatching features for correctness. The tests will
2523 load test modules that will be livepatched in various scenarios.
2525 To run all the livepatching tests:
2527 make -C tools/testing/selftests TARGETS=livepatch run_tests
2529 Alternatively, individual tests may be invoked:
2531 tools/testing/selftests/livepatch/test-callbacks.sh
2532 tools/testing/selftests/livepatch/test-livepatch.sh
2533 tools/testing/selftests/livepatch/test-shadow-vars.sh
2538 tristate "Perform selftest on object aggreration manager"
2542 Enable this option to test object aggregation manager on boot
2546 config TEST_STACKINIT
2547 tristate "Test level of stack variable initialization"
2549 Test if the kernel is zero-initializing stack variables and
2550 padding. Coverage is controlled by compiler flags,
2551 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2552 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2557 tristate "Test heap/page initialization"
2559 Test if the kernel is zero-initializing heap and page allocations.
2560 This can be useful to test init_on_alloc and init_on_free features.
2565 tristate "Test HMM (Heterogeneous Memory Management)"
2566 depends on TRANSPARENT_HUGEPAGE
2567 depends on DEVICE_PRIVATE
2571 This is a pseudo device driver solely for testing HMM.
2572 Say M here if you want to build the HMM test module.
2573 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2577 config TEST_FREE_PAGES
2578 tristate "Test freeing pages"
2580 Test that a memory leak does not occur due to a race between
2581 freeing a block of pages and a speculative page reference.
2582 Loading this module is safe if your kernel has the bug fixed.
2583 If the bug is not fixed, it will leak gigabytes of memory and
2584 probably OOM your system.
2587 tristate "Test floating point operations in kernel space"
2588 depends on X86 && !KCOV_INSTRUMENT_ALL
2590 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2591 which will trigger a sequence of floating point operations. This is used
2592 for self-testing floating point control register setting in
2597 config TEST_CLOCKSOURCE_WATCHDOG
2598 tristate "Test clocksource watchdog in kernel space"
2599 depends on CLOCKSOURCE_WATCHDOG
2601 Enable this option to create a kernel module that will trigger
2602 a test of the clocksource watchdog. This module may be loaded
2603 via modprobe or insmod in which case it will run upon being
2604 loaded, or it may be built in, in which case it will run
2609 endif # RUNTIME_TESTING_MENU
2611 config ARCH_USE_MEMTEST
2614 An architecture should select this when it uses early_memtest()
2615 during boot process.
2619 depends on ARCH_USE_MEMTEST
2621 This option adds a kernel parameter 'memtest', which allows memtest
2622 to be set and executed.
2623 memtest=0, mean disabled; -- default
2624 memtest=1, mean do 1 test pattern;
2626 memtest=17, mean do 17 test patterns.
2627 If you are unsure how to answer this question, answer N.
2631 config HYPERV_TESTING
2632 bool "Microsoft Hyper-V driver testing"
2634 depends on HYPERV && DEBUG_FS
2636 Select this option to enable Hyper-V vmbus testing.
2638 endmenu # "Kernel Testing and Coverage"
2640 source "Documentation/Kconfig"
2642 endmenu # Kernel hacking
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