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 !CC_IS_CLANG || (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
319 depends on BPF_SYSCALL
321 Generate deduplicated BTF type information from DWARF debug info.
322 Turning this on expects presence of pahole tool, which will convert
323 DWARF type info into equivalent deduplicated BTF type info.
325 config PAHOLE_HAS_SPLIT_BTF
326 def_bool $(success, test `$(PAHOLE) --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/'` -ge "119")
328 config DEBUG_INFO_BTF_MODULES
330 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
332 Generate compact split BTF type information for kernel modules.
335 bool "Provide GDB scripts for kernel debugging"
337 This creates the required links to GDB helper scripts in the
338 build directory. If you load vmlinux into gdb, the helper
339 scripts will be automatically imported by gdb as well, and
340 additional functions are available to analyze a Linux kernel
341 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
347 int "Warn for stack frames larger than"
349 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
350 default 2048 if PARISC
351 default 1536 if (!64BIT && XTENSA)
352 default 1024 if !64BIT
353 default 2048 if 64BIT
355 Tell gcc to warn at build time for stack frames larger than this.
356 Setting this too low will cause a lot of warnings.
357 Setting it to 0 disables the warning.
359 config STRIP_ASM_SYMS
360 bool "Strip assembler-generated symbols during link"
363 Strip internal assembler-generated symbols during a link (symbols
364 that look like '.Lxxx') so they don't pollute the output of
365 get_wchan() and suchlike.
368 bool "Generate readable assembler code"
369 depends on DEBUG_KERNEL
372 Disable some compiler optimizations that tend to generate human unreadable
373 assembler output. This may make the kernel slightly slower, but it helps
374 to keep kernel developers who have to stare a lot at assembler listings
377 config HEADERS_INSTALL
378 bool "Install uapi headers to usr/include"
381 This option will install uapi headers (headers exported to user-space)
382 into the usr/include directory for use during the kernel build.
383 This is unneeded for building the kernel itself, but needed for some
384 user-space program samples. It is also needed by some features such
385 as uapi header sanity checks.
387 config DEBUG_SECTION_MISMATCH
388 bool "Enable full Section mismatch analysis"
391 The section mismatch analysis checks if there are illegal
392 references from one section to another section.
393 During linktime or runtime, some sections are dropped;
394 any use of code/data previously in these sections would
395 most likely result in an oops.
396 In the code, functions and variables are annotated with
397 __init,, etc. (see the full list in include/linux/init.h),
398 which results in the code/data being placed in specific sections.
399 The section mismatch analysis is always performed after a full
400 kernel build, and enabling this option causes the following
401 additional step to occur:
402 - Add the option -fno-inline-functions-called-once to gcc commands.
403 When inlining a function annotated with __init in a non-init
404 function, we would lose the section information and thus
405 the analysis would not catch the illegal reference.
406 This option tells gcc to inline less (but it does result in
409 config SECTION_MISMATCH_WARN_ONLY
410 bool "Make section mismatch errors non-fatal"
413 If you say N here, the build process will fail if there are any
414 section mismatch, instead of just throwing warnings.
418 config DEBUG_FORCE_FUNCTION_ALIGN_64B
419 bool "Force all function address 64B aligned"
420 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC)
422 There are cases that a commit from one domain changes the function
423 address alignment of other domains, and cause magic performance
424 bump (regression or improvement). Enable this option will help to
425 verify if the bump is caused by function alignment changes, while
426 it will slightly increase the kernel size and affect icache usage.
428 It is mainly for debug and performance tuning use.
431 # Select this config option from the architecture Kconfig, if it
432 # is preferred to always offer frame pointers as a config
433 # option on the architecture (regardless of KERNEL_DEBUG):
435 config ARCH_WANT_FRAME_POINTERS
439 bool "Compile the kernel with frame pointers"
440 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
441 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
443 If you say Y here the resulting kernel image will be slightly
444 larger and slower, but it gives very useful debugging information
445 in case of kernel bugs. (precise oopses/stacktraces/warnings)
447 config STACK_VALIDATION
448 bool "Compile-time stack metadata validation"
449 depends on HAVE_STACK_VALIDATION
452 Add compile-time checks to validate stack metadata, including frame
453 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
454 that runtime stack traces are more reliable.
456 This is also a prerequisite for generation of ORC unwind data, which
457 is needed for CONFIG_UNWINDER_ORC.
459 For more information, see
460 tools/objtool/Documentation/stack-validation.txt.
462 config VMLINUX_VALIDATION
464 depends on STACK_VALIDATION && DEBUG_ENTRY
468 bool "Generate vmlinux.map file when linking"
471 Selecting this option will pass "-Map=vmlinux.map" to ld
472 when linking vmlinux. That file can be useful for verifying
473 and debugging magic section games, and for seeing which
474 pieces of code get eliminated with
475 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
477 config DEBUG_FORCE_WEAK_PER_CPU
478 bool "Force weak per-cpu definitions"
479 depends on DEBUG_KERNEL
481 s390 and alpha require percpu variables in modules to be
482 defined weak to work around addressing range issue which
483 puts the following two restrictions on percpu variable
486 1. percpu symbols must be unique whether static or not
487 2. percpu variables can't be defined inside a function
489 To ensure that generic code follows the above rules, this
490 option forces all percpu variables to be defined as weak.
492 endmenu # "Compiler options"
494 menu "Generic Kernel Debugging Instruments"
497 bool "Magic SysRq key"
500 If you say Y here, you will have some control over the system even
501 if the system crashes for example during kernel debugging (e.g., you
502 will be able to flush the buffer cache to disk, reboot the system
503 immediately or dump some status information). This is accomplished
504 by pressing various keys while holding SysRq (Alt+PrintScreen). It
505 also works on a serial console (on PC hardware at least), if you
506 send a BREAK and then within 5 seconds a command keypress. The
507 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
508 Don't say Y unless you really know what this hack does.
510 config MAGIC_SYSRQ_DEFAULT_ENABLE
511 hex "Enable magic SysRq key functions by default"
512 depends on MAGIC_SYSRQ
515 Specifies which SysRq key functions are enabled by default.
516 This may be set to 1 or 0 to enable or disable them all, or
517 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
519 config MAGIC_SYSRQ_SERIAL
520 bool "Enable magic SysRq key over serial"
521 depends on MAGIC_SYSRQ
524 Many embedded boards have a disconnected TTL level serial which can
525 generate some garbage that can lead to spurious false sysrq detects.
526 This option allows you to decide whether you want to enable the
529 config MAGIC_SYSRQ_SERIAL_SEQUENCE
530 string "Char sequence that enables magic SysRq over serial"
531 depends on MAGIC_SYSRQ_SERIAL
534 Specifies a sequence of characters that can follow BREAK to enable
535 SysRq on a serial console.
537 If unsure, leave an empty string and the option will not be enabled.
540 bool "Debug Filesystem"
542 debugfs is a virtual file system that kernel developers use to put
543 debugging files into. Enable this option to be able to read and
544 write to these files.
546 For detailed documentation on the debugfs API, see
547 Documentation/filesystems/.
552 prompt "Debugfs default access"
554 default DEBUG_FS_ALLOW_ALL
556 This selects the default access restrictions for debugfs.
557 It can be overridden with kernel command line option
558 debugfs=[on,no-mount,off]. The restrictions apply for API access
559 and filesystem registration.
561 config DEBUG_FS_ALLOW_ALL
564 No restrictions apply. Both API and filesystem registration
565 is on. This is the normal default operation.
567 config DEBUG_FS_DISALLOW_MOUNT
568 bool "Do not register debugfs as filesystem"
570 The API is open but filesystem is not loaded. Clients can still do
571 their work and read with debug tools that do not need
574 config DEBUG_FS_ALLOW_NONE
577 Access is off. Clients get -PERM when trying to create nodes in
578 debugfs tree and debugfs is not registered as a filesystem.
579 Client can then back-off or continue without debugfs access.
583 source "lib/Kconfig.kgdb"
584 source "lib/Kconfig.ubsan"
585 source "lib/Kconfig.kcsan"
590 bool "Kernel debugging"
592 Say Y here if you are developing drivers or trying to debug and
593 identify kernel problems.
596 bool "Miscellaneous debug code"
598 depends on DEBUG_KERNEL
600 Say Y here if you need to enable miscellaneous debug code that should
601 be under a more specific debug option but isn't.
603 menu "Networking Debugging"
605 source "net/Kconfig.debug"
607 endmenu # "Networking Debugging"
609 menu "Memory Debugging"
611 source "mm/Kconfig.debug"
614 bool "Debug object operations"
615 depends on DEBUG_KERNEL
617 If you say Y here, additional code will be inserted into the
618 kernel to track the life time of various objects and validate
619 the operations on those objects.
621 config DEBUG_OBJECTS_SELFTEST
622 bool "Debug objects selftest"
623 depends on DEBUG_OBJECTS
625 This enables the selftest of the object debug code.
627 config DEBUG_OBJECTS_FREE
628 bool "Debug objects in freed memory"
629 depends on DEBUG_OBJECTS
631 This enables checks whether a k/v free operation frees an area
632 which contains an object which has not been deactivated
633 properly. This can make kmalloc/kfree-intensive workloads
636 config DEBUG_OBJECTS_TIMERS
637 bool "Debug timer objects"
638 depends on DEBUG_OBJECTS
640 If you say Y here, additional code will be inserted into the
641 timer routines to track the life time of timer objects and
642 validate the timer operations.
644 config DEBUG_OBJECTS_WORK
645 bool "Debug work objects"
646 depends on DEBUG_OBJECTS
648 If you say Y here, additional code will be inserted into the
649 work queue routines to track the life time of work objects and
650 validate the work operations.
652 config DEBUG_OBJECTS_RCU_HEAD
653 bool "Debug RCU callbacks objects"
654 depends on DEBUG_OBJECTS
656 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
658 config DEBUG_OBJECTS_PERCPU_COUNTER
659 bool "Debug percpu counter objects"
660 depends on DEBUG_OBJECTS
662 If you say Y here, additional code will be inserted into the
663 percpu counter routines to track the life time of percpu counter
664 objects and validate the percpu counter operations.
666 config DEBUG_OBJECTS_ENABLE_DEFAULT
667 int "debug_objects bootup default value (0-1)"
670 depends on DEBUG_OBJECTS
672 Debug objects boot parameter default value
675 bool "Debug slab memory allocations"
676 depends on DEBUG_KERNEL && SLAB
678 Say Y here to have the kernel do limited verification on memory
679 allocation as well as poisoning memory on free to catch use of freed
680 memory. This can make kmalloc/kfree-intensive workloads much slower.
683 bool "SLUB debugging on by default"
684 depends on SLUB && SLUB_DEBUG
687 Boot with debugging on by default. SLUB boots by default with
688 the runtime debug capabilities switched off. Enabling this is
689 equivalent to specifying the "slub_debug" parameter on boot.
690 There is no support for more fine grained debug control like
691 possible with slub_debug=xxx. SLUB debugging may be switched
692 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
697 bool "Enable SLUB performance statistics"
698 depends on SLUB && SYSFS
700 SLUB statistics are useful to debug SLUBs allocation behavior in
701 order find ways to optimize the allocator. This should never be
702 enabled for production use since keeping statistics slows down
703 the allocator by a few percentage points. The slabinfo command
704 supports the determination of the most active slabs to figure
705 out which slabs are relevant to a particular load.
706 Try running: slabinfo -DA
708 config HAVE_DEBUG_KMEMLEAK
711 config DEBUG_KMEMLEAK
712 bool "Kernel memory leak detector"
713 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
715 select STACKTRACE if STACKTRACE_SUPPORT
719 Say Y here if you want to enable the memory leak
720 detector. The memory allocation/freeing is traced in a way
721 similar to the Boehm's conservative garbage collector, the
722 difference being that the orphan objects are not freed but
723 only shown in /sys/kernel/debug/kmemleak. Enabling this
724 feature will introduce an overhead to memory
725 allocations. See Documentation/dev-tools/kmemleak.rst for more
728 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
729 of finding leaks due to the slab objects poisoning.
731 In order to access the kmemleak file, debugfs needs to be
732 mounted (usually at /sys/kernel/debug).
734 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
735 int "Kmemleak memory pool size"
736 depends on DEBUG_KMEMLEAK
740 Kmemleak must track all the memory allocations to avoid
741 reporting false positives. Since memory may be allocated or
742 freed before kmemleak is fully initialised, use a static pool
743 of metadata objects to track such callbacks. After kmemleak is
744 fully initialised, this memory pool acts as an emergency one
745 if slab allocations fail.
747 config DEBUG_KMEMLEAK_TEST
748 tristate "Simple test for the kernel memory leak detector"
749 depends on DEBUG_KMEMLEAK && m
751 This option enables a module that explicitly leaks memory.
755 config DEBUG_KMEMLEAK_DEFAULT_OFF
756 bool "Default kmemleak to off"
757 depends on DEBUG_KMEMLEAK
759 Say Y here to disable kmemleak by default. It can then be enabled
760 on the command line via kmemleak=on.
762 config DEBUG_KMEMLEAK_AUTO_SCAN
763 bool "Enable kmemleak auto scan thread on boot up"
765 depends on DEBUG_KMEMLEAK
767 Depending on the cpu, kmemleak scan may be cpu intensive and can
768 stall user tasks at times. This option enables/disables automatic
769 kmemleak scan at boot up.
771 Say N here to disable kmemleak auto scan thread to stop automatic
772 scanning. Disabling this option disables automatic reporting of
777 config DEBUG_STACK_USAGE
778 bool "Stack utilization instrumentation"
779 depends on DEBUG_KERNEL && !IA64
781 Enables the display of the minimum amount of free stack which each
782 task has ever had available in the sysrq-T and sysrq-P debug output.
784 This option will slow down process creation somewhat.
786 config SCHED_STACK_END_CHECK
787 bool "Detect stack corruption on calls to schedule()"
788 depends on DEBUG_KERNEL
791 This option checks for a stack overrun on calls to schedule().
792 If the stack end location is found to be over written always panic as
793 the content of the corrupted region can no longer be trusted.
794 This is to ensure no erroneous behaviour occurs which could result in
795 data corruption or a sporadic crash at a later stage once the region
796 is examined. The runtime overhead introduced is minimal.
798 config ARCH_HAS_DEBUG_VM_PGTABLE
801 An architecture should select this when it can successfully
802 build and run DEBUG_VM_PGTABLE.
806 depends on DEBUG_KERNEL
808 Enable this to turn on extended checks in the virtual-memory system
809 that may impact performance.
813 config DEBUG_VM_VMACACHE
814 bool "Debug VMA caching"
817 Enable this to turn on VMA caching debug information. Doing so
818 can cause significant overhead, so only enable it in non-production
824 bool "Debug VM red-black trees"
827 Enable VM red-black tree debugging information and extra validations.
831 config DEBUG_VM_PGFLAGS
832 bool "Debug page-flags operations"
835 Enables extra validation on page flags operations.
839 config DEBUG_VM_PGTABLE
840 bool "Debug arch page table for semantics compliance"
842 depends on ARCH_HAS_DEBUG_VM_PGTABLE
843 default y if DEBUG_VM
845 This option provides a debug method which can be used to test
846 architecture page table helper functions on various platforms in
847 verifying if they comply with expected generic MM semantics. This
848 will help architecture code in making sure that any changes or
849 new additions of these helpers still conform to expected
850 semantics of the generic MM. Platforms will have to opt in for
851 this through ARCH_HAS_DEBUG_VM_PGTABLE.
855 config ARCH_HAS_DEBUG_VIRTUAL
859 bool "Debug VM translations"
860 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
862 Enable some costly sanity checks in virtual to page code. This can
863 catch mistakes with virt_to_page() and friends.
867 config DEBUG_NOMMU_REGIONS
868 bool "Debug the global anon/private NOMMU mapping region tree"
869 depends on DEBUG_KERNEL && !MMU
871 This option causes the global tree of anonymous and private mapping
872 regions to be regularly checked for invalid topology.
874 config DEBUG_MEMORY_INIT
875 bool "Debug memory initialisation" if EXPERT
878 Enable this for additional checks during memory initialisation.
879 The sanity checks verify aspects of the VM such as the memory model
880 and other information provided by the architecture. Verbose
881 information will be printed at KERN_DEBUG loglevel depending
882 on the mminit_loglevel= command-line option.
886 config MEMORY_NOTIFIER_ERROR_INJECT
887 tristate "Memory hotplug notifier error injection module"
888 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
890 This option provides the ability to inject artificial errors to
891 memory hotplug notifier chain callbacks. It is controlled through
892 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
894 If the notifier call chain should be failed with some events
895 notified, write the error code to "actions/<notifier event>/error".
897 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
899 # cd /sys/kernel/debug/notifier-error-inject/memory
900 # echo -12 > actions/MEM_GOING_OFFLINE/error
901 # echo offline > /sys/devices/system/memory/memoryXXX/state
902 bash: echo: write error: Cannot allocate memory
904 To compile this code as a module, choose M here: the module will
905 be called memory-notifier-error-inject.
909 config DEBUG_PER_CPU_MAPS
910 bool "Debug access to per_cpu maps"
911 depends on DEBUG_KERNEL
914 Say Y to verify that the per_cpu map being accessed has
915 been set up. This adds a fair amount of code to kernel memory
916 and decreases performance.
920 config DEBUG_KMAP_LOCAL
921 bool "Debug kmap_local temporary mappings"
922 depends on DEBUG_KERNEL && KMAP_LOCAL
924 This option enables additional error checking for the kmap_local
925 infrastructure. Disable for production use.
927 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
930 config DEBUG_KMAP_LOCAL_FORCE_MAP
931 bool "Enforce kmap_local temporary mappings"
932 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
934 select DEBUG_KMAP_LOCAL
936 This option enforces temporary mappings through the kmap_local
937 mechanism for non-highmem pages and on non-highmem systems.
938 Disable this for production systems!
941 bool "Highmem debugging"
942 depends on DEBUG_KERNEL && HIGHMEM
943 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
944 select DEBUG_KMAP_LOCAL
946 This option enables additional error checking for high memory
947 systems. Disable for production systems.
949 config HAVE_DEBUG_STACKOVERFLOW
952 config DEBUG_STACKOVERFLOW
953 bool "Check for stack overflows"
954 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
956 Say Y here if you want to check for overflows of kernel, IRQ
957 and exception stacks (if your architecture uses them). This
958 option will show detailed messages if free stack space drops
959 below a certain limit.
961 These kinds of bugs usually occur when call-chains in the
962 kernel get too deep, especially when interrupts are
965 Use this in cases where you see apparently random memory
966 corruption, especially if it appears in 'struct thread_info'
968 If in doubt, say "N".
970 source "lib/Kconfig.kasan"
971 source "lib/Kconfig.kfence"
973 endmenu # "Memory Debugging"
976 bool "Debug shared IRQ handlers"
977 depends on DEBUG_KERNEL
979 Enable this to generate a spurious interrupt just before a shared
980 interrupt handler is deregistered (generating one when registering
981 is currently disabled). Drivers need to handle this correctly. Some
982 don't and need to be caught.
984 menu "Debug Oops, Lockups and Hangs"
989 Say Y here to enable the kernel to panic when it oopses. This
990 has the same effect as setting oops=panic on the kernel command
993 This feature is useful to ensure that the kernel does not do
994 anything erroneous after an oops which could result in data
995 corruption or other issues.
999 config PANIC_ON_OOPS_VALUE
1002 default 0 if !PANIC_ON_OOPS
1003 default 1 if PANIC_ON_OOPS
1005 config PANIC_TIMEOUT
1009 Set the timeout value (in seconds) until a reboot occurs when
1010 the kernel panics. If n = 0, then we wait forever. A timeout
1011 value n > 0 will wait n seconds before rebooting, while a timeout
1012 value n < 0 will reboot immediately.
1014 config LOCKUP_DETECTOR
1017 config SOFTLOCKUP_DETECTOR
1018 bool "Detect Soft Lockups"
1019 depends on DEBUG_KERNEL && !S390
1020 select LOCKUP_DETECTOR
1022 Say Y here to enable the kernel to act as a watchdog to detect
1025 Softlockups are bugs that cause the kernel to loop in kernel
1026 mode for more than 20 seconds, without giving other tasks a
1027 chance to run. The current stack trace is displayed upon
1028 detection and the system will stay locked up.
1030 config BOOTPARAM_SOFTLOCKUP_PANIC
1031 bool "Panic (Reboot) On Soft Lockups"
1032 depends on SOFTLOCKUP_DETECTOR
1034 Say Y here to enable the kernel to panic on "soft lockups",
1035 which are bugs that cause the kernel to loop in kernel
1036 mode for more than 20 seconds (configurable using the watchdog_thresh
1037 sysctl), without giving other tasks a chance to run.
1039 The panic can be used in combination with panic_timeout,
1040 to cause the system to reboot automatically after a
1041 lockup has been detected. This feature is useful for
1042 high-availability systems that have uptime guarantees and
1043 where a lockup must be resolved ASAP.
1047 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
1049 depends on SOFTLOCKUP_DETECTOR
1051 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
1052 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
1054 config HARDLOCKUP_DETECTOR_PERF
1056 select SOFTLOCKUP_DETECTOR
1059 # Enables a timestamp based low pass filter to compensate for perf based
1060 # hard lockup detection which runs too fast due to turbo modes.
1062 config HARDLOCKUP_CHECK_TIMESTAMP
1066 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1067 # lockup detector rather than the perf based detector.
1069 config HARDLOCKUP_DETECTOR
1070 bool "Detect Hard Lockups"
1071 depends on DEBUG_KERNEL && !S390
1072 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1073 select LOCKUP_DETECTOR
1074 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1076 Say Y here to enable the kernel to act as a watchdog to detect
1079 Hardlockups are bugs that cause the CPU to loop in kernel mode
1080 for more than 10 seconds, without letting other interrupts have a
1081 chance to run. The current stack trace is displayed upon detection
1082 and the system will stay locked up.
1084 config BOOTPARAM_HARDLOCKUP_PANIC
1085 bool "Panic (Reboot) On Hard Lockups"
1086 depends on HARDLOCKUP_DETECTOR
1088 Say Y here to enable the kernel to panic on "hard lockups",
1089 which are bugs that cause the kernel to loop in kernel
1090 mode with interrupts disabled for more than 10 seconds (configurable
1091 using the watchdog_thresh sysctl).
1095 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
1097 depends on HARDLOCKUP_DETECTOR
1099 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
1100 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
1102 config DETECT_HUNG_TASK
1103 bool "Detect Hung Tasks"
1104 depends on DEBUG_KERNEL
1105 default SOFTLOCKUP_DETECTOR
1107 Say Y here to enable the kernel to detect "hung tasks",
1108 which are bugs that cause the task to be stuck in
1109 uninterruptible "D" state indefinitely.
1111 When a hung task is detected, the kernel will print the
1112 current stack trace (which you should report), but the
1113 task will stay in uninterruptible state. If lockdep is
1114 enabled then all held locks will also be reported. This
1115 feature has negligible overhead.
1117 config DEFAULT_HUNG_TASK_TIMEOUT
1118 int "Default timeout for hung task detection (in seconds)"
1119 depends on DETECT_HUNG_TASK
1122 This option controls the default timeout (in seconds) used
1123 to determine when a task has become non-responsive and should
1126 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1127 sysctl or by writing a value to
1128 /proc/sys/kernel/hung_task_timeout_secs.
1130 A timeout of 0 disables the check. The default is two minutes.
1131 Keeping the default should be fine in most cases.
1133 config BOOTPARAM_HUNG_TASK_PANIC
1134 bool "Panic (Reboot) On Hung Tasks"
1135 depends on DETECT_HUNG_TASK
1137 Say Y here to enable the kernel to panic on "hung tasks",
1138 which are bugs that cause the kernel to leave a task stuck
1139 in uninterruptible "D" state.
1141 The panic can be used in combination with panic_timeout,
1142 to cause the system to reboot automatically after a
1143 hung task has been detected. This feature is useful for
1144 high-availability systems that have uptime guarantees and
1145 where a hung tasks must be resolved ASAP.
1149 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
1151 depends on DETECT_HUNG_TASK
1153 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
1154 default 1 if BOOTPARAM_HUNG_TASK_PANIC
1157 bool "Detect Workqueue Stalls"
1158 depends on DEBUG_KERNEL
1160 Say Y here to enable stall detection on workqueues. If a
1161 worker pool doesn't make forward progress on a pending work
1162 item for over a given amount of time, 30s by default, a
1163 warning message is printed along with dump of workqueue
1164 state. This can be configured through kernel parameter
1165 "workqueue.watchdog_thresh" and its sysfs counterpart.
1168 tristate "Test module to generate lockups"
1171 This builds the "test_lockup" module that helps to make sure
1172 that watchdogs and lockup detectors are working properly.
1174 Depending on module parameters it could emulate soft or hard
1175 lockup, "hung task", or locking arbitrary lock for a long time.
1176 Also it could generate series of lockups with cooling-down periods.
1180 endmenu # "Debug lockups and hangs"
1182 menu "Scheduler Debugging"
1185 bool "Collect scheduler debugging info"
1186 depends on DEBUG_KERNEL && PROC_FS
1189 If you say Y here, the /proc/sched_debug file will be provided
1190 that can help debug the scheduler. The runtime overhead of this
1198 bool "Collect scheduler statistics"
1199 depends on DEBUG_KERNEL && PROC_FS
1202 If you say Y here, additional code will be inserted into the
1203 scheduler and related routines to collect statistics about
1204 scheduler behavior and provide them in /proc/schedstat. These
1205 stats may be useful for both tuning and debugging the scheduler
1206 If you aren't debugging the scheduler or trying to tune a specific
1207 application, you can say N to avoid the very slight overhead
1212 config DEBUG_TIMEKEEPING
1213 bool "Enable extra timekeeping sanity checking"
1215 This option will enable additional timekeeping sanity checks
1216 which may be helpful when diagnosing issues where timekeeping
1217 problems are suspected.
1219 This may include checks in the timekeeping hotpaths, so this
1220 option may have a (very small) performance impact to some
1225 config DEBUG_PREEMPT
1226 bool "Debug preemptible kernel"
1227 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1230 If you say Y here then the kernel will use a debug variant of the
1231 commonly used smp_processor_id() function and will print warnings
1232 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1233 will detect preemption count underflows.
1235 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1237 config LOCK_DEBUGGING_SUPPORT
1239 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1242 config PROVE_LOCKING
1243 bool "Lock debugging: prove locking correctness"
1244 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1246 select DEBUG_SPINLOCK
1247 select DEBUG_MUTEXES if !PREEMPT_RT
1248 select DEBUG_RT_MUTEXES if RT_MUTEXES
1250 select DEBUG_WW_MUTEX_SLOWPATH
1251 select DEBUG_LOCK_ALLOC
1252 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1253 select TRACE_IRQFLAGS
1256 This feature enables the kernel to prove that all locking
1257 that occurs in the kernel runtime is mathematically
1258 correct: that under no circumstance could an arbitrary (and
1259 not yet triggered) combination of observed locking
1260 sequences (on an arbitrary number of CPUs, running an
1261 arbitrary number of tasks and interrupt contexts) cause a
1264 In short, this feature enables the kernel to report locking
1265 related deadlocks before they actually occur.
1267 The proof does not depend on how hard and complex a
1268 deadlock scenario would be to trigger: how many
1269 participant CPUs, tasks and irq-contexts would be needed
1270 for it to trigger. The proof also does not depend on
1271 timing: if a race and a resulting deadlock is possible
1272 theoretically (no matter how unlikely the race scenario
1273 is), it will be proven so and will immediately be
1274 reported by the kernel (once the event is observed that
1275 makes the deadlock theoretically possible).
1277 If a deadlock is impossible (i.e. the locking rules, as
1278 observed by the kernel, are mathematically correct), the
1279 kernel reports nothing.
1281 NOTE: this feature can also be enabled for rwlocks, mutexes
1282 and rwsems - in which case all dependencies between these
1283 different locking variants are observed and mapped too, and
1284 the proof of observed correctness is also maintained for an
1285 arbitrary combination of these separate locking variants.
1287 For more details, see Documentation/locking/lockdep-design.rst.
1289 config PROVE_RAW_LOCK_NESTING
1290 bool "Enable raw_spinlock - spinlock nesting checks"
1291 depends on PROVE_LOCKING
1294 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1295 that the lock nesting rules for PREEMPT_RT enabled kernels are
1298 NOTE: There are known nesting problems. So if you enable this
1299 option expect lockdep splats until these problems have been fully
1300 addressed which is work in progress. This config switch allows to
1301 identify and analyze these problems. It will be removed and the
1302 check permanently enabled once the main issues have been fixed.
1304 If unsure, select N.
1307 bool "Lock usage statistics"
1308 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1310 select DEBUG_SPINLOCK
1311 select DEBUG_MUTEXES if !PREEMPT_RT
1312 select DEBUG_RT_MUTEXES if RT_MUTEXES
1313 select DEBUG_LOCK_ALLOC
1316 This feature enables tracking lock contention points
1318 For more details, see Documentation/locking/lockstat.rst
1320 This also enables lock events required by "perf lock",
1322 If you want to use "perf lock", you also need to turn on
1323 CONFIG_EVENT_TRACING.
1325 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1326 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1328 config DEBUG_RT_MUTEXES
1329 bool "RT Mutex debugging, deadlock detection"
1330 depends on DEBUG_KERNEL && RT_MUTEXES
1332 This allows rt mutex semantics violations and rt mutex related
1333 deadlocks (lockups) to be detected and reported automatically.
1335 config DEBUG_SPINLOCK
1336 bool "Spinlock and rw-lock debugging: basic checks"
1337 depends on DEBUG_KERNEL
1338 select UNINLINE_SPIN_UNLOCK
1340 Say Y here and build SMP to catch missing spinlock initialization
1341 and certain other kinds of spinlock errors commonly made. This is
1342 best used in conjunction with the NMI watchdog so that spinlock
1343 deadlocks are also debuggable.
1345 config DEBUG_MUTEXES
1346 bool "Mutex debugging: basic checks"
1347 depends on DEBUG_KERNEL && !PREEMPT_RT
1349 This feature allows mutex semantics violations to be detected and
1352 config DEBUG_WW_MUTEX_SLOWPATH
1353 bool "Wait/wound mutex debugging: Slowpath testing"
1354 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1355 select DEBUG_LOCK_ALLOC
1356 select DEBUG_SPINLOCK
1357 select DEBUG_MUTEXES if !PREEMPT_RT
1358 select DEBUG_RT_MUTEXES if PREEMPT_RT
1360 This feature enables slowpath testing for w/w mutex users by
1361 injecting additional -EDEADLK wound/backoff cases. Together with
1362 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1363 will test all possible w/w mutex interface abuse with the
1364 exception of simply not acquiring all the required locks.
1365 Note that this feature can introduce significant overhead, so
1366 it really should not be enabled in a production or distro kernel,
1367 even a debug kernel. If you are a driver writer, enable it. If
1368 you are a distro, do not.
1371 bool "RW Semaphore debugging: basic checks"
1372 depends on DEBUG_KERNEL
1374 This debugging feature allows mismatched rw semaphore locks
1375 and unlocks to be detected and reported.
1377 config DEBUG_LOCK_ALLOC
1378 bool "Lock debugging: detect incorrect freeing of live locks"
1379 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1380 select DEBUG_SPINLOCK
1381 select DEBUG_MUTEXES if !PREEMPT_RT
1382 select DEBUG_RT_MUTEXES if RT_MUTEXES
1385 This feature will check whether any held lock (spinlock, rwlock,
1386 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1387 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1388 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1389 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1390 held during task exit.
1394 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1399 config LOCKDEP_SMALL
1403 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1404 depends on LOCKDEP && !LOCKDEP_SMALL
1408 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1410 config LOCKDEP_CHAINS_BITS
1411 int "Bitsize for MAX_LOCKDEP_CHAINS"
1412 depends on LOCKDEP && !LOCKDEP_SMALL
1416 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1418 config LOCKDEP_STACK_TRACE_BITS
1419 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1420 depends on LOCKDEP && !LOCKDEP_SMALL
1424 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1426 config LOCKDEP_STACK_TRACE_HASH_BITS
1427 int "Bitsize for STACK_TRACE_HASH_SIZE"
1428 depends on LOCKDEP && !LOCKDEP_SMALL
1432 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1434 config LOCKDEP_CIRCULAR_QUEUE_BITS
1435 int "Bitsize for elements in circular_queue struct"
1440 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1442 config DEBUG_LOCKDEP
1443 bool "Lock dependency engine debugging"
1444 depends on DEBUG_KERNEL && LOCKDEP
1445 select DEBUG_IRQFLAGS
1447 If you say Y here, the lock dependency engine will do
1448 additional runtime checks to debug itself, at the price
1449 of more runtime overhead.
1451 config DEBUG_ATOMIC_SLEEP
1452 bool "Sleep inside atomic section checking"
1453 select PREEMPT_COUNT
1454 depends on DEBUG_KERNEL
1455 depends on !ARCH_NO_PREEMPT
1457 If you say Y here, various routines which may sleep will become very
1458 noisy if they are called inside atomic sections: when a spinlock is
1459 held, inside an rcu read side critical section, inside preempt disabled
1460 sections, inside an interrupt, etc...
1462 config DEBUG_LOCKING_API_SELFTESTS
1463 bool "Locking API boot-time self-tests"
1464 depends on DEBUG_KERNEL
1466 Say Y here if you want the kernel to run a short self-test during
1467 bootup. The self-test checks whether common types of locking bugs
1468 are detected by debugging mechanisms or not. (if you disable
1469 lock debugging then those bugs won't be detected of course.)
1470 The following locking APIs are covered: spinlocks, rwlocks,
1473 config LOCK_TORTURE_TEST
1474 tristate "torture tests for locking"
1475 depends on DEBUG_KERNEL
1478 This option provides a kernel module that runs torture tests
1479 on kernel locking primitives. The kernel module may be built
1480 after the fact on the running kernel to be tested, if desired.
1482 Say Y here if you want kernel locking-primitive torture tests
1483 to be built into the kernel.
1484 Say M if you want these torture tests to build as a module.
1485 Say N if you are unsure.
1487 config WW_MUTEX_SELFTEST
1488 tristate "Wait/wound mutex selftests"
1490 This option provides a kernel module that runs tests on the
1491 on the struct ww_mutex locking API.
1493 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1494 with this test harness.
1496 Say M if you want these self tests to build as a module.
1497 Say N if you are unsure.
1499 config SCF_TORTURE_TEST
1500 tristate "torture tests for smp_call_function*()"
1501 depends on DEBUG_KERNEL
1504 This option provides a kernel module that runs torture tests
1505 on the smp_call_function() family of primitives. The kernel
1506 module may be built after the fact on the running kernel to
1507 be tested, if desired.
1509 config CSD_LOCK_WAIT_DEBUG
1510 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1511 depends on DEBUG_KERNEL
1515 This option enables debug prints when CPUs are slow to respond
1516 to the smp_call_function*() IPI wrappers. These debug prints
1517 include the IPI handler function currently executing (if any)
1518 and relevant stack traces.
1520 endmenu # lock debugging
1522 config TRACE_IRQFLAGS
1523 depends on TRACE_IRQFLAGS_SUPPORT
1526 Enables hooks to interrupt enabling and disabling for
1527 either tracing or lock debugging.
1529 config TRACE_IRQFLAGS_NMI
1531 depends on TRACE_IRQFLAGS
1532 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1534 config DEBUG_IRQFLAGS
1535 bool "Debug IRQ flag manipulation"
1537 Enables checks for potentially unsafe enabling or disabling of
1538 interrupts, such as calling raw_local_irq_restore() when interrupts
1542 bool "Stack backtrace support"
1543 depends on STACKTRACE_SUPPORT
1545 This option causes the kernel to create a /proc/pid/stack for
1546 every process, showing its current stack trace.
1547 It is also used by various kernel debugging features that require
1548 stack trace generation.
1550 config WARN_ALL_UNSEEDED_RANDOM
1551 bool "Warn for all uses of unseeded randomness"
1554 Some parts of the kernel contain bugs relating to their use of
1555 cryptographically secure random numbers before it's actually possible
1556 to generate those numbers securely. This setting ensures that these
1557 flaws don't go unnoticed, by enabling a message, should this ever
1558 occur. This will allow people with obscure setups to know when things
1559 are going wrong, so that they might contact developers about fixing
1562 Unfortunately, on some models of some architectures getting
1563 a fully seeded CRNG is extremely difficult, and so this can
1564 result in dmesg getting spammed for a surprisingly long
1565 time. This is really bad from a security perspective, and
1566 so architecture maintainers really need to do what they can
1567 to get the CRNG seeded sooner after the system is booted.
1568 However, since users cannot do anything actionable to
1569 address this, by default the kernel will issue only a single
1570 warning for the first use of unseeded randomness.
1572 Say Y here if you want to receive warnings for all uses of
1573 unseeded randomness. This will be of use primarily for
1574 those developers interested in improving the security of
1575 Linux kernels running on their architecture (or
1578 config DEBUG_KOBJECT
1579 bool "kobject debugging"
1580 depends on DEBUG_KERNEL
1582 If you say Y here, some extra kobject debugging messages will be sent
1585 config DEBUG_KOBJECT_RELEASE
1586 bool "kobject release debugging"
1587 depends on DEBUG_OBJECTS_TIMERS
1589 kobjects are reference counted objects. This means that their
1590 last reference count put is not predictable, and the kobject can
1591 live on past the point at which a driver decides to drop it's
1592 initial reference to the kobject gained on allocation. An
1593 example of this would be a struct device which has just been
1596 However, some buggy drivers assume that after such an operation,
1597 the memory backing the kobject can be immediately freed. This
1598 goes completely against the principles of a refcounted object.
1600 If you say Y here, the kernel will delay the release of kobjects
1601 on the last reference count to improve the visibility of this
1602 kind of kobject release bug.
1604 config HAVE_DEBUG_BUGVERBOSE
1607 menu "Debug kernel data structures"
1610 bool "Debug linked list manipulation"
1611 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1613 Enable this to turn on extended checks in the linked-list
1619 bool "Debug priority linked list manipulation"
1620 depends on DEBUG_KERNEL
1622 Enable this to turn on extended checks in the priority-ordered
1623 linked-list (plist) walking routines. This checks the entire
1624 list multiple times during each manipulation.
1629 bool "Debug SG table operations"
1630 depends on DEBUG_KERNEL
1632 Enable this to turn on checks on scatter-gather tables. This can
1633 help find problems with drivers that do not properly initialize
1638 config DEBUG_NOTIFIERS
1639 bool "Debug notifier call chains"
1640 depends on DEBUG_KERNEL
1642 Enable this to turn on sanity checking for notifier call chains.
1643 This is most useful for kernel developers to make sure that
1644 modules properly unregister themselves from notifier chains.
1645 This is a relatively cheap check but if you care about maximum
1648 config BUG_ON_DATA_CORRUPTION
1649 bool "Trigger a BUG when data corruption is detected"
1652 Select this option if the kernel should BUG when it encounters
1653 data corruption in kernel memory structures when they get checked
1660 config DEBUG_CREDENTIALS
1661 bool "Debug credential management"
1662 depends on DEBUG_KERNEL
1664 Enable this to turn on some debug checking for credential
1665 management. The additional code keeps track of the number of
1666 pointers from task_structs to any given cred struct, and checks to
1667 see that this number never exceeds the usage count of the cred
1670 Furthermore, if SELinux is enabled, this also checks that the
1671 security pointer in the cred struct is never seen to be invalid.
1675 source "kernel/rcu/Kconfig.debug"
1677 config DEBUG_WQ_FORCE_RR_CPU
1678 bool "Force round-robin CPU selection for unbound work items"
1679 depends on DEBUG_KERNEL
1682 Workqueue used to implicitly guarantee that work items queued
1683 without explicit CPU specified are put on the local CPU. This
1684 guarantee is no longer true and while local CPU is still
1685 preferred work items may be put on foreign CPUs. Kernel
1686 parameter "workqueue.debug_force_rr_cpu" is added to force
1687 round-robin CPU selection to flush out usages which depend on the
1688 now broken guarantee. This config option enables the debug
1689 feature by default. When enabled, memory and cache locality will
1692 config CPU_HOTPLUG_STATE_CONTROL
1693 bool "Enable CPU hotplug state control"
1694 depends on DEBUG_KERNEL
1695 depends on HOTPLUG_CPU
1698 Allows to write steps between "offline" and "online" to the CPUs
1699 sysfs target file so states can be stepped granular. This is a debug
1700 option for now as the hotplug machinery cannot be stopped and
1701 restarted at arbitrary points yet.
1703 Say N if your are unsure.
1706 bool "Latency measuring infrastructure"
1707 depends on DEBUG_KERNEL
1708 depends on STACKTRACE_SUPPORT
1710 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1716 Enable this option if you want to use the LatencyTOP tool
1717 to find out which userspace is blocking on what kernel operations.
1719 source "kernel/trace/Kconfig"
1721 config PROVIDE_OHCI1394_DMA_INIT
1722 bool "Remote debugging over FireWire early on boot"
1723 depends on PCI && X86
1725 If you want to debug problems which hang or crash the kernel early
1726 on boot and the crashing machine has a FireWire port, you can use
1727 this feature to remotely access the memory of the crashed machine
1728 over FireWire. This employs remote DMA as part of the OHCI1394
1729 specification which is now the standard for FireWire controllers.
1731 With remote DMA, you can monitor the printk buffer remotely using
1732 firescope and access all memory below 4GB using fireproxy from gdb.
1733 Even controlling a kernel debugger is possible using remote DMA.
1737 If ohci1394_dma=early is used as boot parameter, it will initialize
1738 all OHCI1394 controllers which are found in the PCI config space.
1740 As all changes to the FireWire bus such as enabling and disabling
1741 devices cause a bus reset and thereby disable remote DMA for all
1742 devices, be sure to have the cable plugged and FireWire enabled on
1743 the debugging host before booting the debug target for debugging.
1745 This code (~1k) is freed after boot. By then, the firewire stack
1746 in charge of the OHCI-1394 controllers should be used instead.
1748 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1750 source "samples/Kconfig"
1752 config ARCH_HAS_DEVMEM_IS_ALLOWED
1755 config STRICT_DEVMEM
1756 bool "Filter access to /dev/mem"
1757 depends on MMU && DEVMEM
1758 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1759 default y if PPC || X86 || ARM64
1761 If this option is disabled, you allow userspace (root) access to all
1762 of memory, including kernel and userspace memory. Accidental
1763 access to this is obviously disastrous, but specific access can
1764 be used by people debugging the kernel. Note that with PAT support
1765 enabled, even in this case there are restrictions on /dev/mem
1766 use due to the cache aliasing requirements.
1768 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1769 file only allows userspace access to PCI space and the BIOS code and
1770 data regions. This is sufficient for dosemu and X and all common
1775 config IO_STRICT_DEVMEM
1776 bool "Filter I/O access to /dev/mem"
1777 depends on STRICT_DEVMEM
1779 If this option is disabled, you allow userspace (root) access to all
1780 io-memory regardless of whether a driver is actively using that
1781 range. Accidental access to this is obviously disastrous, but
1782 specific access can be used by people debugging kernel drivers.
1784 If this option is switched on, the /dev/mem file only allows
1785 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1786 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1787 if the driver using a given range cannot be disabled.
1791 menu "$(SRCARCH) Debugging"
1793 source "arch/$(SRCARCH)/Kconfig.debug"
1797 menu "Kernel Testing and Coverage"
1799 source "lib/kunit/Kconfig"
1801 config NOTIFIER_ERROR_INJECTION
1802 tristate "Notifier error injection"
1803 depends on DEBUG_KERNEL
1806 This option provides the ability to inject artificial errors to
1807 specified notifier chain callbacks. It is useful to test the error
1808 handling of notifier call chain failures.
1812 config PM_NOTIFIER_ERROR_INJECT
1813 tristate "PM notifier error injection module"
1814 depends on PM && NOTIFIER_ERROR_INJECTION
1815 default m if PM_DEBUG
1817 This option provides the ability to inject artificial errors to
1818 PM notifier chain callbacks. It is controlled through debugfs
1819 interface /sys/kernel/debug/notifier-error-inject/pm
1821 If the notifier call chain should be failed with some events
1822 notified, write the error code to "actions/<notifier event>/error".
1824 Example: Inject PM suspend error (-12 = -ENOMEM)
1826 # cd /sys/kernel/debug/notifier-error-inject/pm/
1827 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1828 # echo mem > /sys/power/state
1829 bash: echo: write error: Cannot allocate memory
1831 To compile this code as a module, choose M here: the module will
1832 be called pm-notifier-error-inject.
1836 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1837 tristate "OF reconfig notifier error injection module"
1838 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1840 This option provides the ability to inject artificial errors to
1841 OF reconfig notifier chain callbacks. It is controlled
1842 through debugfs interface under
1843 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1845 If the notifier call chain should be failed with some events
1846 notified, write the error code to "actions/<notifier event>/error".
1848 To compile this code as a module, choose M here: the module will
1849 be called of-reconfig-notifier-error-inject.
1853 config NETDEV_NOTIFIER_ERROR_INJECT
1854 tristate "Netdev notifier error injection module"
1855 depends on NET && NOTIFIER_ERROR_INJECTION
1857 This option provides the ability to inject artificial errors to
1858 netdevice notifier chain callbacks. It is controlled through debugfs
1859 interface /sys/kernel/debug/notifier-error-inject/netdev
1861 If the notifier call chain should be failed with some events
1862 notified, write the error code to "actions/<notifier event>/error".
1864 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1866 # cd /sys/kernel/debug/notifier-error-inject/netdev
1867 # echo -22 > actions/NETDEV_CHANGEMTU/error
1868 # ip link set eth0 mtu 1024
1869 RTNETLINK answers: Invalid argument
1871 To compile this code as a module, choose M here: the module will
1872 be called netdev-notifier-error-inject.
1876 config FUNCTION_ERROR_INJECTION
1878 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1880 config FAULT_INJECTION
1881 bool "Fault-injection framework"
1882 depends on DEBUG_KERNEL
1884 Provide fault-injection framework.
1885 For more details, see Documentation/fault-injection/.
1888 bool "Fault-injection capability for kmalloc"
1889 depends on FAULT_INJECTION
1890 depends on SLAB || SLUB
1892 Provide fault-injection capability for kmalloc.
1894 config FAIL_PAGE_ALLOC
1895 bool "Fault-injection capability for alloc_pages()"
1896 depends on FAULT_INJECTION
1898 Provide fault-injection capability for alloc_pages().
1900 config FAULT_INJECTION_USERCOPY
1901 bool "Fault injection capability for usercopy functions"
1902 depends on FAULT_INJECTION
1904 Provides fault-injection capability to inject failures
1905 in usercopy functions (copy_from_user(), get_user(), ...).
1907 config FAIL_MAKE_REQUEST
1908 bool "Fault-injection capability for disk IO"
1909 depends on FAULT_INJECTION && BLOCK
1911 Provide fault-injection capability for disk IO.
1913 config FAIL_IO_TIMEOUT
1914 bool "Fault-injection capability for faking disk interrupts"
1915 depends on FAULT_INJECTION && BLOCK
1917 Provide fault-injection capability on end IO handling. This
1918 will make the block layer "forget" an interrupt as configured,
1919 thus exercising the error handling.
1921 Only works with drivers that use the generic timeout handling,
1922 for others it won't do anything.
1925 bool "Fault-injection capability for futexes"
1927 depends on FAULT_INJECTION && FUTEX
1929 Provide fault-injection capability for futexes.
1931 config FAULT_INJECTION_DEBUG_FS
1932 bool "Debugfs entries for fault-injection capabilities"
1933 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1935 Enable configuration of fault-injection capabilities via debugfs.
1937 config FAIL_FUNCTION
1938 bool "Fault-injection capability for functions"
1939 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1941 Provide function-based fault-injection capability.
1942 This will allow you to override a specific function with a return
1943 with given return value. As a result, function caller will see
1944 an error value and have to handle it. This is useful to test the
1945 error handling in various subsystems.
1947 config FAIL_MMC_REQUEST
1948 bool "Fault-injection capability for MMC IO"
1949 depends on FAULT_INJECTION_DEBUG_FS && MMC
1951 Provide fault-injection capability for MMC IO.
1952 This will make the mmc core return data errors. This is
1953 useful to test the error handling in the mmc block device
1954 and to test how the mmc host driver handles retries from
1958 bool "Fault-injection capability for SunRPC"
1959 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1961 Provide fault-injection capability for SunRPC and
1964 config FAULT_INJECTION_STACKTRACE_FILTER
1965 bool "stacktrace filter for fault-injection capabilities"
1966 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1969 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1971 Provide stacktrace filter for fault-injection capabilities
1973 config ARCH_HAS_KCOV
1976 An architecture should select this when it can successfully
1977 build and run with CONFIG_KCOV. This typically requires
1978 disabling instrumentation for some early boot code.
1980 config CC_HAS_SANCOV_TRACE_PC
1981 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1985 bool "Code coverage for fuzzing"
1986 depends on ARCH_HAS_KCOV
1987 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1988 depends on !ARCH_WANTS_NO_INSTR || STACK_VALIDATION || \
1989 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
1991 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1993 KCOV exposes kernel code coverage information in a form suitable
1994 for coverage-guided fuzzing (randomized testing).
1996 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1997 different machines and across reboots. If you need stable PC values,
1998 disable RANDOMIZE_BASE.
2000 For more details, see Documentation/dev-tools/kcov.rst.
2002 config KCOV_ENABLE_COMPARISONS
2003 bool "Enable comparison operands collection by KCOV"
2005 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2007 KCOV also exposes operands of every comparison in the instrumented
2008 code along with operand sizes and PCs of the comparison instructions.
2009 These operands can be used by fuzzing engines to improve the quality
2010 of fuzzing coverage.
2012 config KCOV_INSTRUMENT_ALL
2013 bool "Instrument all code by default"
2017 If you are doing generic system call fuzzing (like e.g. syzkaller),
2018 then you will want to instrument the whole kernel and you should
2019 say y here. If you are doing more targeted fuzzing (like e.g.
2020 filesystem fuzzing with AFL) then you will want to enable coverage
2021 for more specific subsets of files, and should say n here.
2023 config KCOV_IRQ_AREA_SIZE
2024 hex "Size of interrupt coverage collection area in words"
2028 KCOV uses preallocated per-cpu areas to collect coverage from
2029 soft interrupts. This specifies the size of those areas in the
2030 number of unsigned long words.
2032 menuconfig RUNTIME_TESTING_MENU
2033 bool "Runtime Testing"
2036 if RUNTIME_TESTING_MENU
2039 tristate "Linux Kernel Dump Test Tool Module"
2042 This module enables testing of the different dumping mechanisms by
2043 inducing system failures at predefined crash points.
2044 If you don't need it: say N
2045 Choose M here to compile this code as a module. The module will be
2048 Documentation on how to use the module can be found in
2049 Documentation/fault-injection/provoke-crashes.rst
2051 config TEST_LIST_SORT
2052 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2054 default KUNIT_ALL_TESTS
2056 Enable this to turn on 'list_sort()' function test. This test is
2057 executed only once during system boot (so affects only boot time),
2058 or at module load time.
2062 config TEST_MIN_HEAP
2063 tristate "Min heap test"
2064 depends on DEBUG_KERNEL || m
2066 Enable this to turn on min heap function tests. This test is
2067 executed only once during system boot (so affects only boot time),
2068 or at module load time.
2073 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2075 default KUNIT_ALL_TESTS
2077 This option enables the self-test function of 'sort()' at boot,
2078 or at module load time.
2083 tristate "64bit/32bit division and modulo test"
2084 depends on DEBUG_KERNEL || m
2086 Enable this to turn on 'do_div()' function test. This test is
2087 executed only once during system boot (so affects only boot time),
2088 or at module load time.
2092 config KPROBES_SANITY_TEST
2093 tristate "Kprobes sanity tests"
2094 depends on DEBUG_KERNEL
2098 This option provides for testing basic kprobes functionality on
2099 boot. Samples of kprobe and kretprobe are inserted and
2100 verified for functionality.
2102 Say N if you are unsure.
2104 config BACKTRACE_SELF_TEST
2105 tristate "Self test for the backtrace code"
2106 depends on DEBUG_KERNEL
2108 This option provides a kernel module that can be used to test
2109 the kernel stack backtrace code. This option is not useful
2110 for distributions or general kernels, but only for kernel
2111 developers working on architecture code.
2113 Note that if you want to also test saved backtraces, you will
2114 have to enable STACKTRACE as well.
2116 Say N if you are unsure.
2118 config TEST_REF_TRACKER
2119 tristate "Self test for reference tracker"
2120 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2123 This option provides a kernel module performing tests
2124 using reference tracker infrastructure.
2126 Say N if you are unsure.
2129 tristate "Red-Black tree test"
2130 depends on DEBUG_KERNEL
2132 A benchmark measuring the performance of the rbtree library.
2133 Also includes rbtree invariant checks.
2135 config REED_SOLOMON_TEST
2136 tristate "Reed-Solomon library test"
2137 depends on DEBUG_KERNEL || m
2139 select REED_SOLOMON_ENC16
2140 select REED_SOLOMON_DEC16
2142 This option enables the self-test function of rslib at boot,
2143 or at module load time.
2147 config INTERVAL_TREE_TEST
2148 tristate "Interval tree test"
2149 depends on DEBUG_KERNEL
2150 select INTERVAL_TREE
2152 A benchmark measuring the performance of the interval tree library
2155 tristate "Per cpu operations test"
2156 depends on m && DEBUG_KERNEL
2158 Enable this option to build test module which validates per-cpu
2163 config ATOMIC64_SELFTEST
2164 tristate "Perform an atomic64_t self-test"
2166 Enable this option to test the atomic64_t functions at boot or
2167 at module load time.
2171 config ASYNC_RAID6_TEST
2172 tristate "Self test for hardware accelerated raid6 recovery"
2173 depends on ASYNC_RAID6_RECOV
2176 This is a one-shot self test that permutes through the
2177 recovery of all the possible two disk failure scenarios for a
2178 N-disk array. Recovery is performed with the asynchronous
2179 raid6 recovery routines, and will optionally use an offload
2180 engine if one is available.
2185 tristate "Test functions located in the hexdump module at runtime"
2187 config STRING_SELFTEST
2188 tristate "Test string functions at runtime"
2190 config TEST_STRING_HELPERS
2191 tristate "Test functions located in the string_helpers module at runtime"
2194 tristate "Test strscpy*() family of functions at runtime"
2197 tristate "Test kstrto*() family of functions at runtime"
2200 tristate "Test printf() family of functions at runtime"
2203 tristate "Test scanf() family of functions at runtime"
2206 tristate "Test bitmap_*() family of functions at runtime"
2208 Enable this option to test the bitmap functions at boot.
2213 tristate "Test functions located in the uuid module at runtime"
2216 tristate "Test the XArray code at runtime"
2218 config TEST_OVERFLOW
2219 tristate "Test check_*_overflow() functions at runtime"
2221 config TEST_RHASHTABLE
2222 tristate "Perform selftest on resizable hash table"
2224 Enable this option to test the rhashtable functions at boot.
2229 tristate "Perform selftest on siphash functions"
2231 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2232 functions on boot (or module load).
2234 This is intended to help people writing architecture-specific
2235 optimized versions. If unsure, say N.
2238 tristate "Perform selftest on IDA functions"
2241 tristate "Perform selftest on priority array manager"
2244 Enable this option to test priority array manager on boot
2249 config TEST_IRQ_TIMINGS
2250 bool "IRQ timings selftest"
2251 depends on IRQ_TIMINGS
2253 Enable this option to test the irq timings code on boot.
2258 tristate "Test module loading with 'hello world' module"
2261 This builds the "test_module" module that emits "Hello, world"
2262 on printk when loaded. It is designed to be used for basic
2263 evaluation of the module loading subsystem (for example when
2264 validating module verification). It lacks any extra dependencies,
2265 and will not normally be loaded by the system unless explicitly
2271 tristate "Test module for compilation of bitops operations"
2274 This builds the "test_bitops" module that is much like the
2275 TEST_LKM module except that it does a basic exercise of the
2276 set/clear_bit macros and get_count_order/long to make sure there are
2277 no compiler warnings from C=1 sparse checker or -Wextra
2278 compilations. It has no dependencies and doesn't run or load unless
2279 explicitly requested by name. for example: modprobe test_bitops.
2284 tristate "Test module for stress/performance analysis of vmalloc allocator"
2289 This builds the "test_vmalloc" module that should be used for
2290 stress and performance analysis. So, any new change for vmalloc
2291 subsystem can be evaluated from performance and stability point
2296 config TEST_USER_COPY
2297 tristate "Test user/kernel boundary protections"
2300 This builds the "test_user_copy" module that runs sanity checks
2301 on the copy_to/from_user infrastructure, making sure basic
2302 user/kernel boundary testing is working. If it fails to load,
2303 a regression has been detected in the user/kernel memory boundary
2309 tristate "Test BPF filter functionality"
2312 This builds the "test_bpf" module that runs various test vectors
2313 against the BPF interpreter or BPF JIT compiler depending on the
2314 current setting. This is in particular useful for BPF JIT compiler
2315 development, but also to run regression tests against changes in
2316 the interpreter code. It also enables test stubs for eBPF maps and
2317 verifier used by user space verifier testsuite.
2321 config TEST_BLACKHOLE_DEV
2322 tristate "Test blackhole netdev functionality"
2325 This builds the "test_blackhole_dev" module that validates the
2326 data path through this blackhole netdev.
2330 config FIND_BIT_BENCHMARK
2331 tristate "Test find_bit functions"
2333 This builds the "test_find_bit" module that measure find_*_bit()
2334 functions performance.
2338 config TEST_FIRMWARE
2339 tristate "Test firmware loading via userspace interface"
2340 depends on FW_LOADER
2342 This builds the "test_firmware" module that creates a userspace
2343 interface for testing firmware loading. This can be used to
2344 control the triggering of firmware loading without needing an
2345 actual firmware-using device. The contents can be rechecked by
2351 tristate "sysctl test driver"
2352 depends on PROC_SYSCTL
2354 This builds the "test_sysctl" module. This driver enables to test the
2355 proc sysctl interfaces available to drivers safely without affecting
2356 production knobs which might alter system functionality.
2360 config BITFIELD_KUNIT
2361 tristate "KUnit test bitfield functions at runtime"
2364 Enable this option to test the bitfield functions at boot.
2366 KUnit tests run during boot and output the results to the debug log
2367 in TAP format (http://testanything.org/). Only useful for kernel devs
2368 running the KUnit test harness, and not intended for inclusion into a
2371 For more information on KUnit and unit tests in general please refer
2372 to the KUnit documentation in Documentation/dev-tools/kunit/.
2376 config HASH_KUNIT_TEST
2377 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2379 default KUNIT_ALL_TESTS
2381 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2382 integer (<linux/hash.h>) hash functions on boot.
2384 KUnit tests run during boot and output the results to the debug log
2385 in TAP format (https://testanything.org/). Only useful for kernel devs
2386 running the KUnit test harness, and not intended for inclusion into a
2389 For more information on KUnit and unit tests in general please refer
2390 to the KUnit documentation in Documentation/dev-tools/kunit/.
2392 This is intended to help people writing architecture-specific
2393 optimized versions. If unsure, say N.
2395 config RESOURCE_KUNIT_TEST
2396 tristate "KUnit test for resource API"
2399 This builds the resource API unit test.
2400 Tests the logic of API provided by resource.c and ioport.h.
2401 For more information on KUnit and unit tests in general please refer
2402 to the KUnit documentation in Documentation/dev-tools/kunit/.
2406 config SYSCTL_KUNIT_TEST
2407 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2409 default KUNIT_ALL_TESTS
2411 This builds the proc sysctl unit test, which runs on boot.
2412 Tests the API contract and implementation correctness of sysctl.
2413 For more information on KUnit and unit tests in general please refer
2414 to the KUnit documentation in Documentation/dev-tools/kunit/.
2418 config LIST_KUNIT_TEST
2419 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2421 default KUNIT_ALL_TESTS
2423 This builds the linked list KUnit test suite.
2424 It tests that the API and basic functionality of the list_head type
2425 and associated macros.
2427 KUnit tests run during boot and output the results to the debug log
2428 in TAP format (https://testanything.org/). Only useful for kernel devs
2429 running the KUnit test harness, and not intended for inclusion into a
2432 For more information on KUnit and unit tests in general please refer
2433 to the KUnit documentation in Documentation/dev-tools/kunit/.
2437 config LINEAR_RANGES_TEST
2438 tristate "KUnit test for linear_ranges"
2440 select LINEAR_RANGES
2442 This builds the linear_ranges unit test, which runs on boot.
2443 Tests the linear_ranges logic correctness.
2444 For more information on KUnit and unit tests in general please refer
2445 to the KUnit documentation in Documentation/dev-tools/kunit/.
2449 config CMDLINE_KUNIT_TEST
2450 tristate "KUnit test for cmdline API"
2453 This builds the cmdline API unit test.
2454 Tests the logic of API provided by cmdline.c.
2455 For more information on KUnit and unit tests in general please refer
2456 to the KUnit documentation in Documentation/dev-tools/kunit/.
2461 tristate "KUnit test for bits.h"
2464 This builds the bits unit test.
2465 Tests the logic of macros defined in bits.h.
2466 For more information on KUnit and unit tests in general please refer
2467 to the KUnit documentation in Documentation/dev-tools/kunit/.
2471 config SLUB_KUNIT_TEST
2472 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2473 depends on SLUB_DEBUG && KUNIT
2474 default KUNIT_ALL_TESTS
2476 This builds SLUB allocator unit test.
2477 Tests SLUB cache debugging functionality.
2478 For more information on KUnit and unit tests in general please refer
2479 to the KUnit documentation in Documentation/dev-tools/kunit/.
2483 config RATIONAL_KUNIT_TEST
2484 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2485 depends on KUNIT && RATIONAL
2486 default KUNIT_ALL_TESTS
2488 This builds the rational math unit test.
2489 For more information on KUnit and unit tests in general please refer
2490 to the KUnit documentation in Documentation/dev-tools/kunit/.
2494 config MEMCPY_KUNIT_TEST
2495 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2497 default KUNIT_ALL_TESTS
2499 Builds unit tests for memcpy(), memmove(), and memset() functions.
2500 For more information on KUnit and unit tests in general please refer
2501 to the KUnit documentation in Documentation/dev-tools/kunit/.
2506 tristate "udelay test driver"
2508 This builds the "udelay_test" module that helps to make sure
2509 that udelay() is working properly.
2513 config TEST_STATIC_KEYS
2514 tristate "Test static keys"
2517 Test the static key interfaces.
2522 tristate "kmod stress tester"
2524 depends on NETDEVICES && NET_CORE && INET # for TUN
2526 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2532 Test the kernel's module loading mechanism: kmod. kmod implements
2533 support to load modules using the Linux kernel's usermode helper.
2534 This test provides a series of tests against kmod.
2536 Although technically you can either build test_kmod as a module or
2537 into the kernel we disallow building it into the kernel since
2538 it stress tests request_module() and this will very likely cause
2539 some issues by taking over precious threads available from other
2540 module load requests, ultimately this could be fatal.
2544 tools/testing/selftests/kmod/kmod.sh --help
2548 config TEST_DEBUG_VIRTUAL
2549 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2550 depends on DEBUG_VIRTUAL
2552 Test the kernel's ability to detect incorrect calls to
2553 virt_to_phys() done against the non-linear part of the
2554 kernel's virtual address map.
2558 config TEST_MEMCAT_P
2559 tristate "Test memcat_p() helper function"
2561 Test the memcat_p() helper for correctly merging two
2562 pointer arrays together.
2566 config TEST_LIVEPATCH
2567 tristate "Test livepatching"
2569 depends on DYNAMIC_DEBUG
2570 depends on LIVEPATCH
2573 Test kernel livepatching features for correctness. The tests will
2574 load test modules that will be livepatched in various scenarios.
2576 To run all the livepatching tests:
2578 make -C tools/testing/selftests TARGETS=livepatch run_tests
2580 Alternatively, individual tests may be invoked:
2582 tools/testing/selftests/livepatch/test-callbacks.sh
2583 tools/testing/selftests/livepatch/test-livepatch.sh
2584 tools/testing/selftests/livepatch/test-shadow-vars.sh
2589 tristate "Perform selftest on object aggreration manager"
2593 Enable this option to test object aggregation manager on boot
2597 config TEST_STACKINIT
2598 tristate "Test level of stack variable initialization"
2600 Test if the kernel is zero-initializing stack variables and
2601 padding. Coverage is controlled by compiler flags,
2602 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2603 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2608 tristate "Test heap/page initialization"
2610 Test if the kernel is zero-initializing heap and page allocations.
2611 This can be useful to test init_on_alloc and init_on_free features.
2616 tristate "Test HMM (Heterogeneous Memory Management)"
2617 depends on TRANSPARENT_HUGEPAGE
2618 depends on DEVICE_PRIVATE
2622 This is a pseudo device driver solely for testing HMM.
2623 Say M here if you want to build the HMM test module.
2624 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2628 config TEST_FREE_PAGES
2629 tristate "Test freeing pages"
2631 Test that a memory leak does not occur due to a race between
2632 freeing a block of pages and a speculative page reference.
2633 Loading this module is safe if your kernel has the bug fixed.
2634 If the bug is not fixed, it will leak gigabytes of memory and
2635 probably OOM your system.
2638 tristate "Test floating point operations in kernel space"
2639 depends on X86 && !KCOV_INSTRUMENT_ALL
2641 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2642 which will trigger a sequence of floating point operations. This is used
2643 for self-testing floating point control register setting in
2648 config TEST_CLOCKSOURCE_WATCHDOG
2649 tristate "Test clocksource watchdog in kernel space"
2650 depends on CLOCKSOURCE_WATCHDOG
2652 Enable this option to create a kernel module that will trigger
2653 a test of the clocksource watchdog. This module may be loaded
2654 via modprobe or insmod in which case it will run upon being
2655 loaded, or it may be built in, in which case it will run
2660 endif # RUNTIME_TESTING_MENU
2662 config ARCH_USE_MEMTEST
2665 An architecture should select this when it uses early_memtest()
2666 during boot process.
2670 depends on ARCH_USE_MEMTEST
2672 This option adds a kernel parameter 'memtest', which allows memtest
2673 to be set and executed.
2674 memtest=0, mean disabled; -- default
2675 memtest=1, mean do 1 test pattern;
2677 memtest=17, mean do 17 test patterns.
2678 If you are unsure how to answer this question, answer N.
2682 config HYPERV_TESTING
2683 bool "Microsoft Hyper-V driver testing"
2685 depends on HYPERV && DEBUG_FS
2687 Select this option to enable Hyper-V vmbus testing.
2689 endmenu # "Kernel Testing and Coverage"
2691 source "Documentation/Kconfig"
2693 endmenu # Kernel hacking
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