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" if EXPERT
421 There are cases that a commit from one domain changes the function
422 address alignment of other domains, and cause magic performance
423 bump (regression or improvement). Enable this option will help to
424 verify if the bump is caused by function alignment changes, while
425 it will slightly increase the kernel size and affect icache usage.
427 It is mainly for debug and performance tuning use.
430 # Select this config option from the architecture Kconfig, if it
431 # is preferred to always offer frame pointers as a config
432 # option on the architecture (regardless of KERNEL_DEBUG):
434 config ARCH_WANT_FRAME_POINTERS
438 bool "Compile the kernel with frame pointers"
439 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
440 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
442 If you say Y here the resulting kernel image will be slightly
443 larger and slower, but it gives very useful debugging information
444 in case of kernel bugs. (precise oopses/stacktraces/warnings)
446 config STACK_VALIDATION
447 bool "Compile-time stack metadata validation"
448 depends on HAVE_STACK_VALIDATION
451 Add compile-time checks to validate stack metadata, including frame
452 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
453 that runtime stack traces are more reliable.
455 This is also a prerequisite for generation of ORC unwind data, which
456 is needed for CONFIG_UNWINDER_ORC.
458 For more information, see
459 tools/objtool/Documentation/stack-validation.txt.
461 config VMLINUX_VALIDATION
463 depends on STACK_VALIDATION && DEBUG_ENTRY
467 bool "Generate vmlinux.map file when linking"
470 Selecting this option will pass "-Map=vmlinux.map" to ld
471 when linking vmlinux. That file can be useful for verifying
472 and debugging magic section games, and for seeing which
473 pieces of code get eliminated with
474 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
476 config DEBUG_FORCE_WEAK_PER_CPU
477 bool "Force weak per-cpu definitions"
478 depends on DEBUG_KERNEL
480 s390 and alpha require percpu variables in modules to be
481 defined weak to work around addressing range issue which
482 puts the following two restrictions on percpu variable
485 1. percpu symbols must be unique whether static or not
486 2. percpu variables can't be defined inside a function
488 To ensure that generic code follows the above rules, this
489 option forces all percpu variables to be defined as weak.
491 endmenu # "Compiler options"
493 menu "Generic Kernel Debugging Instruments"
496 bool "Magic SysRq key"
499 If you say Y here, you will have some control over the system even
500 if the system crashes for example during kernel debugging (e.g., you
501 will be able to flush the buffer cache to disk, reboot the system
502 immediately or dump some status information). This is accomplished
503 by pressing various keys while holding SysRq (Alt+PrintScreen). It
504 also works on a serial console (on PC hardware at least), if you
505 send a BREAK and then within 5 seconds a command keypress. The
506 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
507 Don't say Y unless you really know what this hack does.
509 config MAGIC_SYSRQ_DEFAULT_ENABLE
510 hex "Enable magic SysRq key functions by default"
511 depends on MAGIC_SYSRQ
514 Specifies which SysRq key functions are enabled by default.
515 This may be set to 1 or 0 to enable or disable them all, or
516 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
518 config MAGIC_SYSRQ_SERIAL
519 bool "Enable magic SysRq key over serial"
520 depends on MAGIC_SYSRQ
523 Many embedded boards have a disconnected TTL level serial which can
524 generate some garbage that can lead to spurious false sysrq detects.
525 This option allows you to decide whether you want to enable the
528 config MAGIC_SYSRQ_SERIAL_SEQUENCE
529 string "Char sequence that enables magic SysRq over serial"
530 depends on MAGIC_SYSRQ_SERIAL
533 Specifies a sequence of characters that can follow BREAK to enable
534 SysRq on a serial console.
536 If unsure, leave an empty string and the option will not be enabled.
539 bool "Debug Filesystem"
541 debugfs is a virtual file system that kernel developers use to put
542 debugging files into. Enable this option to be able to read and
543 write to these files.
545 For detailed documentation on the debugfs API, see
546 Documentation/filesystems/.
551 prompt "Debugfs default access"
553 default DEBUG_FS_ALLOW_ALL
555 This selects the default access restrictions for debugfs.
556 It can be overridden with kernel command line option
557 debugfs=[on,no-mount,off]. The restrictions apply for API access
558 and filesystem registration.
560 config DEBUG_FS_ALLOW_ALL
563 No restrictions apply. Both API and filesystem registration
564 is on. This is the normal default operation.
566 config DEBUG_FS_DISALLOW_MOUNT
567 bool "Do not register debugfs as filesystem"
569 The API is open but filesystem is not loaded. Clients can still do
570 their work and read with debug tools that do not need
573 config DEBUG_FS_ALLOW_NONE
576 Access is off. Clients get -PERM when trying to create nodes in
577 debugfs tree and debugfs is not registered as a filesystem.
578 Client can then back-off or continue without debugfs access.
582 source "lib/Kconfig.kgdb"
583 source "lib/Kconfig.ubsan"
584 source "lib/Kconfig.kcsan"
589 bool "Kernel debugging"
591 Say Y here if you are developing drivers or trying to debug and
592 identify kernel problems.
595 bool "Miscellaneous debug code"
597 depends on DEBUG_KERNEL
599 Say Y here if you need to enable miscellaneous debug code that should
600 be under a more specific debug option but isn't.
602 menu "Networking Debugging"
604 source "net/Kconfig.debug"
606 endmenu # "Networking Debugging"
608 menu "Memory Debugging"
610 source "mm/Kconfig.debug"
613 bool "Debug object operations"
614 depends on DEBUG_KERNEL
616 If you say Y here, additional code will be inserted into the
617 kernel to track the life time of various objects and validate
618 the operations on those objects.
620 config DEBUG_OBJECTS_SELFTEST
621 bool "Debug objects selftest"
622 depends on DEBUG_OBJECTS
624 This enables the selftest of the object debug code.
626 config DEBUG_OBJECTS_FREE
627 bool "Debug objects in freed memory"
628 depends on DEBUG_OBJECTS
630 This enables checks whether a k/v free operation frees an area
631 which contains an object which has not been deactivated
632 properly. This can make kmalloc/kfree-intensive workloads
635 config DEBUG_OBJECTS_TIMERS
636 bool "Debug timer objects"
637 depends on DEBUG_OBJECTS
639 If you say Y here, additional code will be inserted into the
640 timer routines to track the life time of timer objects and
641 validate the timer operations.
643 config DEBUG_OBJECTS_WORK
644 bool "Debug work objects"
645 depends on DEBUG_OBJECTS
647 If you say Y here, additional code will be inserted into the
648 work queue routines to track the life time of work objects and
649 validate the work operations.
651 config DEBUG_OBJECTS_RCU_HEAD
652 bool "Debug RCU callbacks objects"
653 depends on DEBUG_OBJECTS
655 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
657 config DEBUG_OBJECTS_PERCPU_COUNTER
658 bool "Debug percpu counter objects"
659 depends on DEBUG_OBJECTS
661 If you say Y here, additional code will be inserted into the
662 percpu counter routines to track the life time of percpu counter
663 objects and validate the percpu counter operations.
665 config DEBUG_OBJECTS_ENABLE_DEFAULT
666 int "debug_objects bootup default value (0-1)"
669 depends on DEBUG_OBJECTS
671 Debug objects boot parameter default value
674 bool "Debug slab memory allocations"
675 depends on DEBUG_KERNEL && SLAB
677 Say Y here to have the kernel do limited verification on memory
678 allocation as well as poisoning memory on free to catch use of freed
679 memory. This can make kmalloc/kfree-intensive workloads much slower.
682 bool "SLUB debugging on by default"
683 depends on SLUB && SLUB_DEBUG
686 Boot with debugging on by default. SLUB boots by default with
687 the runtime debug capabilities switched off. Enabling this is
688 equivalent to specifying the "slub_debug" parameter on boot.
689 There is no support for more fine grained debug control like
690 possible with slub_debug=xxx. SLUB debugging may be switched
691 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
696 bool "Enable SLUB performance statistics"
697 depends on SLUB && SYSFS
699 SLUB statistics are useful to debug SLUBs allocation behavior in
700 order find ways to optimize the allocator. This should never be
701 enabled for production use since keeping statistics slows down
702 the allocator by a few percentage points. The slabinfo command
703 supports the determination of the most active slabs to figure
704 out which slabs are relevant to a particular load.
705 Try running: slabinfo -DA
707 config HAVE_DEBUG_KMEMLEAK
710 config DEBUG_KMEMLEAK
711 bool "Kernel memory leak detector"
712 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
714 select STACKTRACE if STACKTRACE_SUPPORT
718 Say Y here if you want to enable the memory leak
719 detector. The memory allocation/freeing is traced in a way
720 similar to the Boehm's conservative garbage collector, the
721 difference being that the orphan objects are not freed but
722 only shown in /sys/kernel/debug/kmemleak. Enabling this
723 feature will introduce an overhead to memory
724 allocations. See Documentation/dev-tools/kmemleak.rst for more
727 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
728 of finding leaks due to the slab objects poisoning.
730 In order to access the kmemleak file, debugfs needs to be
731 mounted (usually at /sys/kernel/debug).
733 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
734 int "Kmemleak memory pool size"
735 depends on DEBUG_KMEMLEAK
739 Kmemleak must track all the memory allocations to avoid
740 reporting false positives. Since memory may be allocated or
741 freed before kmemleak is fully initialised, use a static pool
742 of metadata objects to track such callbacks. After kmemleak is
743 fully initialised, this memory pool acts as an emergency one
744 if slab allocations fail.
746 config DEBUG_KMEMLEAK_TEST
747 tristate "Simple test for the kernel memory leak detector"
748 depends on DEBUG_KMEMLEAK && m
750 This option enables a module that explicitly leaks memory.
754 config DEBUG_KMEMLEAK_DEFAULT_OFF
755 bool "Default kmemleak to off"
756 depends on DEBUG_KMEMLEAK
758 Say Y here to disable kmemleak by default. It can then be enabled
759 on the command line via kmemleak=on.
761 config DEBUG_KMEMLEAK_AUTO_SCAN
762 bool "Enable kmemleak auto scan thread on boot up"
764 depends on DEBUG_KMEMLEAK
766 Depending on the cpu, kmemleak scan may be cpu intensive and can
767 stall user tasks at times. This option enables/disables automatic
768 kmemleak scan at boot up.
770 Say N here to disable kmemleak auto scan thread to stop automatic
771 scanning. Disabling this option disables automatic reporting of
776 config DEBUG_STACK_USAGE
777 bool "Stack utilization instrumentation"
778 depends on DEBUG_KERNEL && !IA64
780 Enables the display of the minimum amount of free stack which each
781 task has ever had available in the sysrq-T and sysrq-P debug output.
783 This option will slow down process creation somewhat.
785 config SCHED_STACK_END_CHECK
786 bool "Detect stack corruption on calls to schedule()"
787 depends on DEBUG_KERNEL
790 This option checks for a stack overrun on calls to schedule().
791 If the stack end location is found to be over written always panic as
792 the content of the corrupted region can no longer be trusted.
793 This is to ensure no erroneous behaviour occurs which could result in
794 data corruption or a sporadic crash at a later stage once the region
795 is examined. The runtime overhead introduced is minimal.
797 config ARCH_HAS_DEBUG_VM_PGTABLE
800 An architecture should select this when it can successfully
801 build and run DEBUG_VM_PGTABLE.
805 depends on DEBUG_KERNEL
807 Enable this to turn on extended checks in the virtual-memory system
808 that may impact performance.
812 config DEBUG_VM_VMACACHE
813 bool "Debug VMA caching"
816 Enable this to turn on VMA caching debug information. Doing so
817 can cause significant overhead, so only enable it in non-production
823 bool "Debug VM red-black trees"
826 Enable VM red-black tree debugging information and extra validations.
830 config DEBUG_VM_PGFLAGS
831 bool "Debug page-flags operations"
834 Enables extra validation on page flags operations.
838 config DEBUG_VM_PGTABLE
839 bool "Debug arch page table for semantics compliance"
841 depends on ARCH_HAS_DEBUG_VM_PGTABLE
842 default y if DEBUG_VM
844 This option provides a debug method which can be used to test
845 architecture page table helper functions on various platforms in
846 verifying if they comply with expected generic MM semantics. This
847 will help architecture code in making sure that any changes or
848 new additions of these helpers still conform to expected
849 semantics of the generic MM. Platforms will have to opt in for
850 this through ARCH_HAS_DEBUG_VM_PGTABLE.
854 config ARCH_HAS_DEBUG_VIRTUAL
858 bool "Debug VM translations"
859 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
861 Enable some costly sanity checks in virtual to page code. This can
862 catch mistakes with virt_to_page() and friends.
866 config DEBUG_NOMMU_REGIONS
867 bool "Debug the global anon/private NOMMU mapping region tree"
868 depends on DEBUG_KERNEL && !MMU
870 This option causes the global tree of anonymous and private mapping
871 regions to be regularly checked for invalid topology.
873 config DEBUG_MEMORY_INIT
874 bool "Debug memory initialisation" if EXPERT
877 Enable this for additional checks during memory initialisation.
878 The sanity checks verify aspects of the VM such as the memory model
879 and other information provided by the architecture. Verbose
880 information will be printed at KERN_DEBUG loglevel depending
881 on the mminit_loglevel= command-line option.
885 config MEMORY_NOTIFIER_ERROR_INJECT
886 tristate "Memory hotplug notifier error injection module"
887 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
889 This option provides the ability to inject artificial errors to
890 memory hotplug notifier chain callbacks. It is controlled through
891 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
893 If the notifier call chain should be failed with some events
894 notified, write the error code to "actions/<notifier event>/error".
896 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
898 # cd /sys/kernel/debug/notifier-error-inject/memory
899 # echo -12 > actions/MEM_GOING_OFFLINE/error
900 # echo offline > /sys/devices/system/memory/memoryXXX/state
901 bash: echo: write error: Cannot allocate memory
903 To compile this code as a module, choose M here: the module will
904 be called memory-notifier-error-inject.
908 config DEBUG_PER_CPU_MAPS
909 bool "Debug access to per_cpu maps"
910 depends on DEBUG_KERNEL
913 Say Y to verify that the per_cpu map being accessed has
914 been set up. This adds a fair amount of code to kernel memory
915 and decreases performance.
919 config DEBUG_KMAP_LOCAL
920 bool "Debug kmap_local temporary mappings"
921 depends on DEBUG_KERNEL && KMAP_LOCAL
923 This option enables additional error checking for the kmap_local
924 infrastructure. Disable for production use.
926 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
929 config DEBUG_KMAP_LOCAL_FORCE_MAP
930 bool "Enforce kmap_local temporary mappings"
931 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
933 select DEBUG_KMAP_LOCAL
935 This option enforces temporary mappings through the kmap_local
936 mechanism for non-highmem pages and on non-highmem systems.
937 Disable this for production systems!
940 bool "Highmem debugging"
941 depends on DEBUG_KERNEL && HIGHMEM
942 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
943 select DEBUG_KMAP_LOCAL
945 This option enables additional error checking for high memory
946 systems. Disable for production systems.
948 config HAVE_DEBUG_STACKOVERFLOW
951 config DEBUG_STACKOVERFLOW
952 bool "Check for stack overflows"
953 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
955 Say Y here if you want to check for overflows of kernel, IRQ
956 and exception stacks (if your architecture uses them). This
957 option will show detailed messages if free stack space drops
958 below a certain limit.
960 These kinds of bugs usually occur when call-chains in the
961 kernel get too deep, especially when interrupts are
964 Use this in cases where you see apparently random memory
965 corruption, especially if it appears in 'struct thread_info'
967 If in doubt, say "N".
969 source "lib/Kconfig.kasan"
970 source "lib/Kconfig.kfence"
972 endmenu # "Memory Debugging"
975 bool "Debug shared IRQ handlers"
976 depends on DEBUG_KERNEL
978 Enable this to generate a spurious interrupt just before a shared
979 interrupt handler is deregistered (generating one when registering
980 is currently disabled). Drivers need to handle this correctly. Some
981 don't and need to be caught.
983 menu "Debug Oops, Lockups and Hangs"
988 Say Y here to enable the kernel to panic when it oopses. This
989 has the same effect as setting oops=panic on the kernel command
992 This feature is useful to ensure that the kernel does not do
993 anything erroneous after an oops which could result in data
994 corruption or other issues.
998 config PANIC_ON_OOPS_VALUE
1001 default 0 if !PANIC_ON_OOPS
1002 default 1 if PANIC_ON_OOPS
1004 config PANIC_TIMEOUT
1008 Set the timeout value (in seconds) until a reboot occurs when
1009 the kernel panics. If n = 0, then we wait forever. A timeout
1010 value n > 0 will wait n seconds before rebooting, while a timeout
1011 value n < 0 will reboot immediately.
1013 config LOCKUP_DETECTOR
1016 config SOFTLOCKUP_DETECTOR
1017 bool "Detect Soft Lockups"
1018 depends on DEBUG_KERNEL && !S390
1019 select LOCKUP_DETECTOR
1021 Say Y here to enable the kernel to act as a watchdog to detect
1024 Softlockups are bugs that cause the kernel to loop in kernel
1025 mode for more than 20 seconds, without giving other tasks a
1026 chance to run. The current stack trace is displayed upon
1027 detection and the system will stay locked up.
1029 config BOOTPARAM_SOFTLOCKUP_PANIC
1030 bool "Panic (Reboot) On Soft Lockups"
1031 depends on SOFTLOCKUP_DETECTOR
1033 Say Y here to enable the kernel to panic on "soft lockups",
1034 which are bugs that cause the kernel to loop in kernel
1035 mode for more than 20 seconds (configurable using the watchdog_thresh
1036 sysctl), without giving other tasks a chance to run.
1038 The panic can be used in combination with panic_timeout,
1039 to cause the system to reboot automatically after a
1040 lockup has been detected. This feature is useful for
1041 high-availability systems that have uptime guarantees and
1042 where a lockup must be resolved ASAP.
1046 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
1048 depends on SOFTLOCKUP_DETECTOR
1050 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
1051 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
1053 config HARDLOCKUP_DETECTOR_PERF
1055 select SOFTLOCKUP_DETECTOR
1058 # Enables a timestamp based low pass filter to compensate for perf based
1059 # hard lockup detection which runs too fast due to turbo modes.
1061 config HARDLOCKUP_CHECK_TIMESTAMP
1065 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1066 # lockup detector rather than the perf based detector.
1068 config HARDLOCKUP_DETECTOR
1069 bool "Detect Hard Lockups"
1070 depends on DEBUG_KERNEL && !S390
1071 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1072 select LOCKUP_DETECTOR
1073 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1075 Say Y here to enable the kernel to act as a watchdog to detect
1078 Hardlockups are bugs that cause the CPU to loop in kernel mode
1079 for more than 10 seconds, without letting other interrupts have a
1080 chance to run. The current stack trace is displayed upon detection
1081 and the system will stay locked up.
1083 config BOOTPARAM_HARDLOCKUP_PANIC
1084 bool "Panic (Reboot) On Hard Lockups"
1085 depends on HARDLOCKUP_DETECTOR
1087 Say Y here to enable the kernel to panic on "hard lockups",
1088 which are bugs that cause the kernel to loop in kernel
1089 mode with interrupts disabled for more than 10 seconds (configurable
1090 using the watchdog_thresh sysctl).
1094 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
1096 depends on HARDLOCKUP_DETECTOR
1098 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
1099 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
1101 config DETECT_HUNG_TASK
1102 bool "Detect Hung Tasks"
1103 depends on DEBUG_KERNEL
1104 default SOFTLOCKUP_DETECTOR
1106 Say Y here to enable the kernel to detect "hung tasks",
1107 which are bugs that cause the task to be stuck in
1108 uninterruptible "D" state indefinitely.
1110 When a hung task is detected, the kernel will print the
1111 current stack trace (which you should report), but the
1112 task will stay in uninterruptible state. If lockdep is
1113 enabled then all held locks will also be reported. This
1114 feature has negligible overhead.
1116 config DEFAULT_HUNG_TASK_TIMEOUT
1117 int "Default timeout for hung task detection (in seconds)"
1118 depends on DETECT_HUNG_TASK
1121 This option controls the default timeout (in seconds) used
1122 to determine when a task has become non-responsive and should
1125 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1126 sysctl or by writing a value to
1127 /proc/sys/kernel/hung_task_timeout_secs.
1129 A timeout of 0 disables the check. The default is two minutes.
1130 Keeping the default should be fine in most cases.
1132 config BOOTPARAM_HUNG_TASK_PANIC
1133 bool "Panic (Reboot) On Hung Tasks"
1134 depends on DETECT_HUNG_TASK
1136 Say Y here to enable the kernel to panic on "hung tasks",
1137 which are bugs that cause the kernel to leave a task stuck
1138 in uninterruptible "D" state.
1140 The panic can be used in combination with panic_timeout,
1141 to cause the system to reboot automatically after a
1142 hung task has been detected. This feature is useful for
1143 high-availability systems that have uptime guarantees and
1144 where a hung tasks must be resolved ASAP.
1148 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
1150 depends on DETECT_HUNG_TASK
1152 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
1153 default 1 if BOOTPARAM_HUNG_TASK_PANIC
1156 bool "Detect Workqueue Stalls"
1157 depends on DEBUG_KERNEL
1159 Say Y here to enable stall detection on workqueues. If a
1160 worker pool doesn't make forward progress on a pending work
1161 item for over a given amount of time, 30s by default, a
1162 warning message is printed along with dump of workqueue
1163 state. This can be configured through kernel parameter
1164 "workqueue.watchdog_thresh" and its sysfs counterpart.
1167 tristate "Test module to generate lockups"
1170 This builds the "test_lockup" module that helps to make sure
1171 that watchdogs and lockup detectors are working properly.
1173 Depending on module parameters it could emulate soft or hard
1174 lockup, "hung task", or locking arbitrary lock for a long time.
1175 Also it could generate series of lockups with cooling-down periods.
1179 endmenu # "Debug lockups and hangs"
1181 menu "Scheduler Debugging"
1184 bool "Collect scheduler debugging info"
1185 depends on DEBUG_KERNEL && PROC_FS
1188 If you say Y here, the /proc/sched_debug file will be provided
1189 that can help debug the scheduler. The runtime overhead of this
1197 bool "Collect scheduler statistics"
1198 depends on DEBUG_KERNEL && PROC_FS
1201 If you say Y here, additional code will be inserted into the
1202 scheduler and related routines to collect statistics about
1203 scheduler behavior and provide them in /proc/schedstat. These
1204 stats may be useful for both tuning and debugging the scheduler
1205 If you aren't debugging the scheduler or trying to tune a specific
1206 application, you can say N to avoid the very slight overhead
1211 config DEBUG_TIMEKEEPING
1212 bool "Enable extra timekeeping sanity checking"
1214 This option will enable additional timekeeping sanity checks
1215 which may be helpful when diagnosing issues where timekeeping
1216 problems are suspected.
1218 This may include checks in the timekeeping hotpaths, so this
1219 option may have a (very small) performance impact to some
1224 config DEBUG_PREEMPT
1225 bool "Debug preemptible kernel"
1226 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1229 If you say Y here then the kernel will use a debug variant of the
1230 commonly used smp_processor_id() function and will print warnings
1231 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1232 will detect preemption count underflows.
1234 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1236 config LOCK_DEBUGGING_SUPPORT
1238 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1241 config PROVE_LOCKING
1242 bool "Lock debugging: prove locking correctness"
1243 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1245 select DEBUG_SPINLOCK
1246 select DEBUG_MUTEXES if !PREEMPT_RT
1247 select DEBUG_RT_MUTEXES if RT_MUTEXES
1249 select DEBUG_WW_MUTEX_SLOWPATH
1250 select DEBUG_LOCK_ALLOC
1251 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1252 select TRACE_IRQFLAGS
1255 This feature enables the kernel to prove that all locking
1256 that occurs in the kernel runtime is mathematically
1257 correct: that under no circumstance could an arbitrary (and
1258 not yet triggered) combination of observed locking
1259 sequences (on an arbitrary number of CPUs, running an
1260 arbitrary number of tasks and interrupt contexts) cause a
1263 In short, this feature enables the kernel to report locking
1264 related deadlocks before they actually occur.
1266 The proof does not depend on how hard and complex a
1267 deadlock scenario would be to trigger: how many
1268 participant CPUs, tasks and irq-contexts would be needed
1269 for it to trigger. The proof also does not depend on
1270 timing: if a race and a resulting deadlock is possible
1271 theoretically (no matter how unlikely the race scenario
1272 is), it will be proven so and will immediately be
1273 reported by the kernel (once the event is observed that
1274 makes the deadlock theoretically possible).
1276 If a deadlock is impossible (i.e. the locking rules, as
1277 observed by the kernel, are mathematically correct), the
1278 kernel reports nothing.
1280 NOTE: this feature can also be enabled for rwlocks, mutexes
1281 and rwsems - in which case all dependencies between these
1282 different locking variants are observed and mapped too, and
1283 the proof of observed correctness is also maintained for an
1284 arbitrary combination of these separate locking variants.
1286 For more details, see Documentation/locking/lockdep-design.rst.
1288 config PROVE_RAW_LOCK_NESTING
1289 bool "Enable raw_spinlock - spinlock nesting checks"
1290 depends on PROVE_LOCKING
1293 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1294 that the lock nesting rules for PREEMPT_RT enabled kernels are
1297 NOTE: There are known nesting problems. So if you enable this
1298 option expect lockdep splats until these problems have been fully
1299 addressed which is work in progress. This config switch allows to
1300 identify and analyze these problems. It will be removed and the
1301 check permanently enabled once the main issues have been fixed.
1303 If unsure, select N.
1306 bool "Lock usage statistics"
1307 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1309 select DEBUG_SPINLOCK
1310 select DEBUG_MUTEXES if !PREEMPT_RT
1311 select DEBUG_RT_MUTEXES if RT_MUTEXES
1312 select DEBUG_LOCK_ALLOC
1315 This feature enables tracking lock contention points
1317 For more details, see Documentation/locking/lockstat.rst
1319 This also enables lock events required by "perf lock",
1321 If you want to use "perf lock", you also need to turn on
1322 CONFIG_EVENT_TRACING.
1324 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1325 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1327 config DEBUG_RT_MUTEXES
1328 bool "RT Mutex debugging, deadlock detection"
1329 depends on DEBUG_KERNEL && RT_MUTEXES
1331 This allows rt mutex semantics violations and rt mutex related
1332 deadlocks (lockups) to be detected and reported automatically.
1334 config DEBUG_SPINLOCK
1335 bool "Spinlock and rw-lock debugging: basic checks"
1336 depends on DEBUG_KERNEL
1337 select UNINLINE_SPIN_UNLOCK
1339 Say Y here and build SMP to catch missing spinlock initialization
1340 and certain other kinds of spinlock errors commonly made. This is
1341 best used in conjunction with the NMI watchdog so that spinlock
1342 deadlocks are also debuggable.
1344 config DEBUG_MUTEXES
1345 bool "Mutex debugging: basic checks"
1346 depends on DEBUG_KERNEL && !PREEMPT_RT
1348 This feature allows mutex semantics violations to be detected and
1351 config DEBUG_WW_MUTEX_SLOWPATH
1352 bool "Wait/wound mutex debugging: Slowpath testing"
1353 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1354 select DEBUG_LOCK_ALLOC
1355 select DEBUG_SPINLOCK
1356 select DEBUG_MUTEXES if !PREEMPT_RT
1357 select DEBUG_RT_MUTEXES if PREEMPT_RT
1359 This feature enables slowpath testing for w/w mutex users by
1360 injecting additional -EDEADLK wound/backoff cases. Together with
1361 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1362 will test all possible w/w mutex interface abuse with the
1363 exception of simply not acquiring all the required locks.
1364 Note that this feature can introduce significant overhead, so
1365 it really should not be enabled in a production or distro kernel,
1366 even a debug kernel. If you are a driver writer, enable it. If
1367 you are a distro, do not.
1370 bool "RW Semaphore debugging: basic checks"
1371 depends on DEBUG_KERNEL
1373 This debugging feature allows mismatched rw semaphore locks
1374 and unlocks to be detected and reported.
1376 config DEBUG_LOCK_ALLOC
1377 bool "Lock debugging: detect incorrect freeing of live locks"
1378 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1379 select DEBUG_SPINLOCK
1380 select DEBUG_MUTEXES if !PREEMPT_RT
1381 select DEBUG_RT_MUTEXES if RT_MUTEXES
1384 This feature will check whether any held lock (spinlock, rwlock,
1385 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1386 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1387 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1388 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1389 held during task exit.
1393 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1398 config LOCKDEP_SMALL
1402 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1403 depends on LOCKDEP && !LOCKDEP_SMALL
1407 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1409 config LOCKDEP_CHAINS_BITS
1410 int "Bitsize for MAX_LOCKDEP_CHAINS"
1411 depends on LOCKDEP && !LOCKDEP_SMALL
1415 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1417 config LOCKDEP_STACK_TRACE_BITS
1418 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1419 depends on LOCKDEP && !LOCKDEP_SMALL
1423 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1425 config LOCKDEP_STACK_TRACE_HASH_BITS
1426 int "Bitsize for STACK_TRACE_HASH_SIZE"
1427 depends on LOCKDEP && !LOCKDEP_SMALL
1431 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1433 config LOCKDEP_CIRCULAR_QUEUE_BITS
1434 int "Bitsize for elements in circular_queue struct"
1439 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1441 config DEBUG_LOCKDEP
1442 bool "Lock dependency engine debugging"
1443 depends on DEBUG_KERNEL && LOCKDEP
1444 select DEBUG_IRQFLAGS
1446 If you say Y here, the lock dependency engine will do
1447 additional runtime checks to debug itself, at the price
1448 of more runtime overhead.
1450 config DEBUG_ATOMIC_SLEEP
1451 bool "Sleep inside atomic section checking"
1452 select PREEMPT_COUNT
1453 depends on DEBUG_KERNEL
1454 depends on !ARCH_NO_PREEMPT
1456 If you say Y here, various routines which may sleep will become very
1457 noisy if they are called inside atomic sections: when a spinlock is
1458 held, inside an rcu read side critical section, inside preempt disabled
1459 sections, inside an interrupt, etc...
1461 config DEBUG_LOCKING_API_SELFTESTS
1462 bool "Locking API boot-time self-tests"
1463 depends on DEBUG_KERNEL
1465 Say Y here if you want the kernel to run a short self-test during
1466 bootup. The self-test checks whether common types of locking bugs
1467 are detected by debugging mechanisms or not. (if you disable
1468 lock debugging then those bugs won't be detected of course.)
1469 The following locking APIs are covered: spinlocks, rwlocks,
1472 config LOCK_TORTURE_TEST
1473 tristate "torture tests for locking"
1474 depends on DEBUG_KERNEL
1477 This option provides a kernel module that runs torture tests
1478 on kernel locking primitives. The kernel module may be built
1479 after the fact on the running kernel to be tested, if desired.
1481 Say Y here if you want kernel locking-primitive torture tests
1482 to be built into the kernel.
1483 Say M if you want these torture tests to build as a module.
1484 Say N if you are unsure.
1486 config WW_MUTEX_SELFTEST
1487 tristate "Wait/wound mutex selftests"
1489 This option provides a kernel module that runs tests on the
1490 on the struct ww_mutex locking API.
1492 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1493 with this test harness.
1495 Say M if you want these self tests to build as a module.
1496 Say N if you are unsure.
1498 config SCF_TORTURE_TEST
1499 tristate "torture tests for smp_call_function*()"
1500 depends on DEBUG_KERNEL
1503 This option provides a kernel module that runs torture tests
1504 on the smp_call_function() family of primitives. The kernel
1505 module may be built after the fact on the running kernel to
1506 be tested, if desired.
1508 config CSD_LOCK_WAIT_DEBUG
1509 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1510 depends on DEBUG_KERNEL
1514 This option enables debug prints when CPUs are slow to respond
1515 to the smp_call_function*() IPI wrappers. These debug prints
1516 include the IPI handler function currently executing (if any)
1517 and relevant stack traces.
1519 endmenu # lock debugging
1521 config TRACE_IRQFLAGS
1522 depends on TRACE_IRQFLAGS_SUPPORT
1525 Enables hooks to interrupt enabling and disabling for
1526 either tracing or lock debugging.
1528 config TRACE_IRQFLAGS_NMI
1530 depends on TRACE_IRQFLAGS
1531 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1533 config DEBUG_IRQFLAGS
1534 bool "Debug IRQ flag manipulation"
1536 Enables checks for potentially unsafe enabling or disabling of
1537 interrupts, such as calling raw_local_irq_restore() when interrupts
1541 bool "Stack backtrace support"
1542 depends on STACKTRACE_SUPPORT
1544 This option causes the kernel to create a /proc/pid/stack for
1545 every process, showing its current stack trace.
1546 It is also used by various kernel debugging features that require
1547 stack trace generation.
1549 config WARN_ALL_UNSEEDED_RANDOM
1550 bool "Warn for all uses of unseeded randomness"
1553 Some parts of the kernel contain bugs relating to their use of
1554 cryptographically secure random numbers before it's actually possible
1555 to generate those numbers securely. This setting ensures that these
1556 flaws don't go unnoticed, by enabling a message, should this ever
1557 occur. This will allow people with obscure setups to know when things
1558 are going wrong, so that they might contact developers about fixing
1561 Unfortunately, on some models of some architectures getting
1562 a fully seeded CRNG is extremely difficult, and so this can
1563 result in dmesg getting spammed for a surprisingly long
1564 time. This is really bad from a security perspective, and
1565 so architecture maintainers really need to do what they can
1566 to get the CRNG seeded sooner after the system is booted.
1567 However, since users cannot do anything actionable to
1568 address this, by default the kernel will issue only a single
1569 warning for the first use of unseeded randomness.
1571 Say Y here if you want to receive warnings for all uses of
1572 unseeded randomness. This will be of use primarily for
1573 those developers interested in improving the security of
1574 Linux kernels running on their architecture (or
1577 config DEBUG_KOBJECT
1578 bool "kobject debugging"
1579 depends on DEBUG_KERNEL
1581 If you say Y here, some extra kobject debugging messages will be sent
1584 config DEBUG_KOBJECT_RELEASE
1585 bool "kobject release debugging"
1586 depends on DEBUG_OBJECTS_TIMERS
1588 kobjects are reference counted objects. This means that their
1589 last reference count put is not predictable, and the kobject can
1590 live on past the point at which a driver decides to drop it's
1591 initial reference to the kobject gained on allocation. An
1592 example of this would be a struct device which has just been
1595 However, some buggy drivers assume that after such an operation,
1596 the memory backing the kobject can be immediately freed. This
1597 goes completely against the principles of a refcounted object.
1599 If you say Y here, the kernel will delay the release of kobjects
1600 on the last reference count to improve the visibility of this
1601 kind of kobject release bug.
1603 config HAVE_DEBUG_BUGVERBOSE
1606 menu "Debug kernel data structures"
1609 bool "Debug linked list manipulation"
1610 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1612 Enable this to turn on extended checks in the linked-list
1618 bool "Debug priority linked list manipulation"
1619 depends on DEBUG_KERNEL
1621 Enable this to turn on extended checks in the priority-ordered
1622 linked-list (plist) walking routines. This checks the entire
1623 list multiple times during each manipulation.
1628 bool "Debug SG table operations"
1629 depends on DEBUG_KERNEL
1631 Enable this to turn on checks on scatter-gather tables. This can
1632 help find problems with drivers that do not properly initialize
1637 config DEBUG_NOTIFIERS
1638 bool "Debug notifier call chains"
1639 depends on DEBUG_KERNEL
1641 Enable this to turn on sanity checking for notifier call chains.
1642 This is most useful for kernel developers to make sure that
1643 modules properly unregister themselves from notifier chains.
1644 This is a relatively cheap check but if you care about maximum
1647 config BUG_ON_DATA_CORRUPTION
1648 bool "Trigger a BUG when data corruption is detected"
1651 Select this option if the kernel should BUG when it encounters
1652 data corruption in kernel memory structures when they get checked
1659 config DEBUG_CREDENTIALS
1660 bool "Debug credential management"
1661 depends on DEBUG_KERNEL
1663 Enable this to turn on some debug checking for credential
1664 management. The additional code keeps track of the number of
1665 pointers from task_structs to any given cred struct, and checks to
1666 see that this number never exceeds the usage count of the cred
1669 Furthermore, if SELinux is enabled, this also checks that the
1670 security pointer in the cred struct is never seen to be invalid.
1674 source "kernel/rcu/Kconfig.debug"
1676 config DEBUG_WQ_FORCE_RR_CPU
1677 bool "Force round-robin CPU selection for unbound work items"
1678 depends on DEBUG_KERNEL
1681 Workqueue used to implicitly guarantee that work items queued
1682 without explicit CPU specified are put on the local CPU. This
1683 guarantee is no longer true and while local CPU is still
1684 preferred work items may be put on foreign CPUs. Kernel
1685 parameter "workqueue.debug_force_rr_cpu" is added to force
1686 round-robin CPU selection to flush out usages which depend on the
1687 now broken guarantee. This config option enables the debug
1688 feature by default. When enabled, memory and cache locality will
1691 config CPU_HOTPLUG_STATE_CONTROL
1692 bool "Enable CPU hotplug state control"
1693 depends on DEBUG_KERNEL
1694 depends on HOTPLUG_CPU
1697 Allows to write steps between "offline" and "online" to the CPUs
1698 sysfs target file so states can be stepped granular. This is a debug
1699 option for now as the hotplug machinery cannot be stopped and
1700 restarted at arbitrary points yet.
1702 Say N if your are unsure.
1705 bool "Latency measuring infrastructure"
1706 depends on DEBUG_KERNEL
1707 depends on STACKTRACE_SUPPORT
1709 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1715 Enable this option if you want to use the LatencyTOP tool
1716 to find out which userspace is blocking on what kernel operations.
1718 source "kernel/trace/Kconfig"
1720 config PROVIDE_OHCI1394_DMA_INIT
1721 bool "Remote debugging over FireWire early on boot"
1722 depends on PCI && X86
1724 If you want to debug problems which hang or crash the kernel early
1725 on boot and the crashing machine has a FireWire port, you can use
1726 this feature to remotely access the memory of the crashed machine
1727 over FireWire. This employs remote DMA as part of the OHCI1394
1728 specification which is now the standard for FireWire controllers.
1730 With remote DMA, you can monitor the printk buffer remotely using
1731 firescope and access all memory below 4GB using fireproxy from gdb.
1732 Even controlling a kernel debugger is possible using remote DMA.
1736 If ohci1394_dma=early is used as boot parameter, it will initialize
1737 all OHCI1394 controllers which are found in the PCI config space.
1739 As all changes to the FireWire bus such as enabling and disabling
1740 devices cause a bus reset and thereby disable remote DMA for all
1741 devices, be sure to have the cable plugged and FireWire enabled on
1742 the debugging host before booting the debug target for debugging.
1744 This code (~1k) is freed after boot. By then, the firewire stack
1745 in charge of the OHCI-1394 controllers should be used instead.
1747 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1749 source "samples/Kconfig"
1751 config ARCH_HAS_DEVMEM_IS_ALLOWED
1754 config STRICT_DEVMEM
1755 bool "Filter access to /dev/mem"
1756 depends on MMU && DEVMEM
1757 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1758 default y if PPC || X86 || ARM64
1760 If this option is disabled, you allow userspace (root) access to all
1761 of memory, including kernel and userspace memory. Accidental
1762 access to this is obviously disastrous, but specific access can
1763 be used by people debugging the kernel. Note that with PAT support
1764 enabled, even in this case there are restrictions on /dev/mem
1765 use due to the cache aliasing requirements.
1767 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1768 file only allows userspace access to PCI space and the BIOS code and
1769 data regions. This is sufficient for dosemu and X and all common
1774 config IO_STRICT_DEVMEM
1775 bool "Filter I/O access to /dev/mem"
1776 depends on STRICT_DEVMEM
1778 If this option is disabled, you allow userspace (root) access to all
1779 io-memory regardless of whether a driver is actively using that
1780 range. Accidental access to this is obviously disastrous, but
1781 specific access can be used by people debugging kernel drivers.
1783 If this option is switched on, the /dev/mem file only allows
1784 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1785 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1786 if the driver using a given range cannot be disabled.
1790 menu "$(SRCARCH) Debugging"
1792 source "arch/$(SRCARCH)/Kconfig.debug"
1796 menu "Kernel Testing and Coverage"
1798 source "lib/kunit/Kconfig"
1800 config NOTIFIER_ERROR_INJECTION
1801 tristate "Notifier error injection"
1802 depends on DEBUG_KERNEL
1805 This option provides the ability to inject artificial errors to
1806 specified notifier chain callbacks. It is useful to test the error
1807 handling of notifier call chain failures.
1811 config PM_NOTIFIER_ERROR_INJECT
1812 tristate "PM notifier error injection module"
1813 depends on PM && NOTIFIER_ERROR_INJECTION
1814 default m if PM_DEBUG
1816 This option provides the ability to inject artificial errors to
1817 PM notifier chain callbacks. It is controlled through debugfs
1818 interface /sys/kernel/debug/notifier-error-inject/pm
1820 If the notifier call chain should be failed with some events
1821 notified, write the error code to "actions/<notifier event>/error".
1823 Example: Inject PM suspend error (-12 = -ENOMEM)
1825 # cd /sys/kernel/debug/notifier-error-inject/pm/
1826 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1827 # echo mem > /sys/power/state
1828 bash: echo: write error: Cannot allocate memory
1830 To compile this code as a module, choose M here: the module will
1831 be called pm-notifier-error-inject.
1835 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1836 tristate "OF reconfig notifier error injection module"
1837 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1839 This option provides the ability to inject artificial errors to
1840 OF reconfig notifier chain callbacks. It is controlled
1841 through debugfs interface under
1842 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1844 If the notifier call chain should be failed with some events
1845 notified, write the error code to "actions/<notifier event>/error".
1847 To compile this code as a module, choose M here: the module will
1848 be called of-reconfig-notifier-error-inject.
1852 config NETDEV_NOTIFIER_ERROR_INJECT
1853 tristate "Netdev notifier error injection module"
1854 depends on NET && NOTIFIER_ERROR_INJECTION
1856 This option provides the ability to inject artificial errors to
1857 netdevice notifier chain callbacks. It is controlled through debugfs
1858 interface /sys/kernel/debug/notifier-error-inject/netdev
1860 If the notifier call chain should be failed with some events
1861 notified, write the error code to "actions/<notifier event>/error".
1863 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1865 # cd /sys/kernel/debug/notifier-error-inject/netdev
1866 # echo -22 > actions/NETDEV_CHANGEMTU/error
1867 # ip link set eth0 mtu 1024
1868 RTNETLINK answers: Invalid argument
1870 To compile this code as a module, choose M here: the module will
1871 be called netdev-notifier-error-inject.
1875 config FUNCTION_ERROR_INJECTION
1877 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1879 config FAULT_INJECTION
1880 bool "Fault-injection framework"
1881 depends on DEBUG_KERNEL
1883 Provide fault-injection framework.
1884 For more details, see Documentation/fault-injection/.
1887 bool "Fault-injection capability for kmalloc"
1888 depends on FAULT_INJECTION
1889 depends on SLAB || SLUB
1891 Provide fault-injection capability for kmalloc.
1893 config FAIL_PAGE_ALLOC
1894 bool "Fault-injection capability for alloc_pages()"
1895 depends on FAULT_INJECTION
1897 Provide fault-injection capability for alloc_pages().
1899 config FAULT_INJECTION_USERCOPY
1900 bool "Fault injection capability for usercopy functions"
1901 depends on FAULT_INJECTION
1903 Provides fault-injection capability to inject failures
1904 in usercopy functions (copy_from_user(), get_user(), ...).
1906 config FAIL_MAKE_REQUEST
1907 bool "Fault-injection capability for disk IO"
1908 depends on FAULT_INJECTION && BLOCK
1910 Provide fault-injection capability for disk IO.
1912 config FAIL_IO_TIMEOUT
1913 bool "Fault-injection capability for faking disk interrupts"
1914 depends on FAULT_INJECTION && BLOCK
1916 Provide fault-injection capability on end IO handling. This
1917 will make the block layer "forget" an interrupt as configured,
1918 thus exercising the error handling.
1920 Only works with drivers that use the generic timeout handling,
1921 for others it won't do anything.
1924 bool "Fault-injection capability for futexes"
1926 depends on FAULT_INJECTION && FUTEX
1928 Provide fault-injection capability for futexes.
1930 config FAULT_INJECTION_DEBUG_FS
1931 bool "Debugfs entries for fault-injection capabilities"
1932 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1934 Enable configuration of fault-injection capabilities via debugfs.
1936 config FAIL_FUNCTION
1937 bool "Fault-injection capability for functions"
1938 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1940 Provide function-based fault-injection capability.
1941 This will allow you to override a specific function with a return
1942 with given return value. As a result, function caller will see
1943 an error value and have to handle it. This is useful to test the
1944 error handling in various subsystems.
1946 config FAIL_MMC_REQUEST
1947 bool "Fault-injection capability for MMC IO"
1948 depends on FAULT_INJECTION_DEBUG_FS && MMC
1950 Provide fault-injection capability for MMC IO.
1951 This will make the mmc core return data errors. This is
1952 useful to test the error handling in the mmc block device
1953 and to test how the mmc host driver handles retries from
1957 bool "Fault-injection capability for SunRPC"
1958 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1960 Provide fault-injection capability for SunRPC and
1963 config FAULT_INJECTION_STACKTRACE_FILTER
1964 bool "stacktrace filter for fault-injection capabilities"
1965 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1968 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1970 Provide stacktrace filter for fault-injection capabilities
1972 config ARCH_HAS_KCOV
1975 An architecture should select this when it can successfully
1976 build and run with CONFIG_KCOV. This typically requires
1977 disabling instrumentation for some early boot code.
1979 config CC_HAS_SANCOV_TRACE_PC
1980 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1984 bool "Code coverage for fuzzing"
1985 depends on ARCH_HAS_KCOV
1986 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1988 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1990 KCOV exposes kernel code coverage information in a form suitable
1991 for coverage-guided fuzzing (randomized testing).
1993 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1994 different machines and across reboots. If you need stable PC values,
1995 disable RANDOMIZE_BASE.
1997 For more details, see Documentation/dev-tools/kcov.rst.
1999 config KCOV_ENABLE_COMPARISONS
2000 bool "Enable comparison operands collection by KCOV"
2002 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2004 KCOV also exposes operands of every comparison in the instrumented
2005 code along with operand sizes and PCs of the comparison instructions.
2006 These operands can be used by fuzzing engines to improve the quality
2007 of fuzzing coverage.
2009 config KCOV_INSTRUMENT_ALL
2010 bool "Instrument all code by default"
2014 If you are doing generic system call fuzzing (like e.g. syzkaller),
2015 then you will want to instrument the whole kernel and you should
2016 say y here. If you are doing more targeted fuzzing (like e.g.
2017 filesystem fuzzing with AFL) then you will want to enable coverage
2018 for more specific subsets of files, and should say n here.
2020 config KCOV_IRQ_AREA_SIZE
2021 hex "Size of interrupt coverage collection area in words"
2025 KCOV uses preallocated per-cpu areas to collect coverage from
2026 soft interrupts. This specifies the size of those areas in the
2027 number of unsigned long words.
2029 menuconfig RUNTIME_TESTING_MENU
2030 bool "Runtime Testing"
2033 if RUNTIME_TESTING_MENU
2036 tristate "Linux Kernel Dump Test Tool Module"
2039 This module enables testing of the different dumping mechanisms by
2040 inducing system failures at predefined crash points.
2041 If you don't need it: say N
2042 Choose M here to compile this code as a module. The module will be
2045 Documentation on how to use the module can be found in
2046 Documentation/fault-injection/provoke-crashes.rst
2048 config TEST_LIST_SORT
2049 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2051 default KUNIT_ALL_TESTS
2053 Enable this to turn on 'list_sort()' function test. This test is
2054 executed only once during system boot (so affects only boot time),
2055 or at module load time.
2059 config TEST_MIN_HEAP
2060 tristate "Min heap test"
2061 depends on DEBUG_KERNEL || m
2063 Enable this to turn on min heap function tests. This test is
2064 executed only once during system boot (so affects only boot time),
2065 or at module load time.
2070 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2072 default KUNIT_ALL_TESTS
2074 This option enables the self-test function of 'sort()' at boot,
2075 or at module load time.
2080 tristate "64bit/32bit division and modulo test"
2081 depends on DEBUG_KERNEL || m
2083 Enable this to turn on 'do_div()' function test. This test is
2084 executed only once during system boot (so affects only boot time),
2085 or at module load time.
2089 config KPROBES_SANITY_TEST
2090 tristate "Kprobes sanity tests"
2091 depends on DEBUG_KERNEL
2095 This option provides for testing basic kprobes functionality on
2096 boot. Samples of kprobe and kretprobe are inserted and
2097 verified for functionality.
2099 Say N if you are unsure.
2101 config BACKTRACE_SELF_TEST
2102 tristate "Self test for the backtrace code"
2103 depends on DEBUG_KERNEL
2105 This option provides a kernel module that can be used to test
2106 the kernel stack backtrace code. This option is not useful
2107 for distributions or general kernels, but only for kernel
2108 developers working on architecture code.
2110 Note that if you want to also test saved backtraces, you will
2111 have to enable STACKTRACE as well.
2113 Say N if you are unsure.
2115 config TEST_REF_TRACKER
2116 tristate "Self test for reference tracker"
2117 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2120 This option provides a kernel module performing tests
2121 using reference tracker infrastructure.
2123 Say N if you are unsure.
2126 tristate "Red-Black tree test"
2127 depends on DEBUG_KERNEL
2129 A benchmark measuring the performance of the rbtree library.
2130 Also includes rbtree invariant checks.
2132 config REED_SOLOMON_TEST
2133 tristate "Reed-Solomon library test"
2134 depends on DEBUG_KERNEL || m
2136 select REED_SOLOMON_ENC16
2137 select REED_SOLOMON_DEC16
2139 This option enables the self-test function of rslib at boot,
2140 or at module load time.
2144 config INTERVAL_TREE_TEST
2145 tristate "Interval tree test"
2146 depends on DEBUG_KERNEL
2147 select INTERVAL_TREE
2149 A benchmark measuring the performance of the interval tree library
2152 tristate "Per cpu operations test"
2153 depends on m && DEBUG_KERNEL
2155 Enable this option to build test module which validates per-cpu
2160 config ATOMIC64_SELFTEST
2161 tristate "Perform an atomic64_t self-test"
2163 Enable this option to test the atomic64_t functions at boot or
2164 at module load time.
2168 config ASYNC_RAID6_TEST
2169 tristate "Self test for hardware accelerated raid6 recovery"
2170 depends on ASYNC_RAID6_RECOV
2173 This is a one-shot self test that permutes through the
2174 recovery of all the possible two disk failure scenarios for a
2175 N-disk array. Recovery is performed with the asynchronous
2176 raid6 recovery routines, and will optionally use an offload
2177 engine if one is available.
2182 tristate "Test functions located in the hexdump module at runtime"
2184 config STRING_SELFTEST
2185 tristate "Test string functions at runtime"
2187 config TEST_STRING_HELPERS
2188 tristate "Test functions located in the string_helpers module at runtime"
2191 tristate "Test strscpy*() family of functions at runtime"
2194 tristate "Test kstrto*() family of functions at runtime"
2197 tristate "Test printf() family of functions at runtime"
2200 tristate "Test scanf() family of functions at runtime"
2203 tristate "Test bitmap_*() family of functions at runtime"
2205 Enable this option to test the bitmap functions at boot.
2210 tristate "Test functions located in the uuid module at runtime"
2213 tristate "Test the XArray code at runtime"
2215 config TEST_OVERFLOW
2216 tristate "Test check_*_overflow() functions at runtime"
2218 config TEST_RHASHTABLE
2219 tristate "Perform selftest on resizable hash table"
2221 Enable this option to test the rhashtable functions at boot.
2226 tristate "Perform selftest on hash functions"
2228 Enable this option to test the kernel's integer (<linux/hash.h>),
2229 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
2230 hash functions on boot (or module load).
2232 This is intended to help people writing architecture-specific
2233 optimized versions. If unsure, say N.
2236 tristate "Perform selftest on IDA functions"
2239 tristate "Perform selftest on priority array manager"
2242 Enable this option to test priority array manager on boot
2247 config TEST_IRQ_TIMINGS
2248 bool "IRQ timings selftest"
2249 depends on IRQ_TIMINGS
2251 Enable this option to test the irq timings code on boot.
2256 tristate "Test module loading with 'hello world' module"
2259 This builds the "test_module" module that emits "Hello, world"
2260 on printk when loaded. It is designed to be used for basic
2261 evaluation of the module loading subsystem (for example when
2262 validating module verification). It lacks any extra dependencies,
2263 and will not normally be loaded by the system unless explicitly
2269 tristate "Test module for compilation of bitops operations"
2272 This builds the "test_bitops" module that is much like the
2273 TEST_LKM module except that it does a basic exercise of the
2274 set/clear_bit macros and get_count_order/long to make sure there are
2275 no compiler warnings from C=1 sparse checker or -Wextra
2276 compilations. It has no dependencies and doesn't run or load unless
2277 explicitly requested by name. for example: modprobe test_bitops.
2282 tristate "Test module for stress/performance analysis of vmalloc allocator"
2287 This builds the "test_vmalloc" module that should be used for
2288 stress and performance analysis. So, any new change for vmalloc
2289 subsystem can be evaluated from performance and stability point
2294 config TEST_USER_COPY
2295 tristate "Test user/kernel boundary protections"
2298 This builds the "test_user_copy" module that runs sanity checks
2299 on the copy_to/from_user infrastructure, making sure basic
2300 user/kernel boundary testing is working. If it fails to load,
2301 a regression has been detected in the user/kernel memory boundary
2307 tristate "Test BPF filter functionality"
2310 This builds the "test_bpf" module that runs various test vectors
2311 against the BPF interpreter or BPF JIT compiler depending on the
2312 current setting. This is in particular useful for BPF JIT compiler
2313 development, but also to run regression tests against changes in
2314 the interpreter code. It also enables test stubs for eBPF maps and
2315 verifier used by user space verifier testsuite.
2319 config TEST_BLACKHOLE_DEV
2320 tristate "Test blackhole netdev functionality"
2323 This builds the "test_blackhole_dev" module that validates the
2324 data path through this blackhole netdev.
2328 config FIND_BIT_BENCHMARK
2329 tristate "Test find_bit functions"
2331 This builds the "test_find_bit" module that measure find_*_bit()
2332 functions performance.
2336 config TEST_FIRMWARE
2337 tristate "Test firmware loading via userspace interface"
2338 depends on FW_LOADER
2340 This builds the "test_firmware" module that creates a userspace
2341 interface for testing firmware loading. This can be used to
2342 control the triggering of firmware loading without needing an
2343 actual firmware-using device. The contents can be rechecked by
2349 tristate "sysctl test driver"
2350 depends on PROC_SYSCTL
2352 This builds the "test_sysctl" module. This driver enables to test the
2353 proc sysctl interfaces available to drivers safely without affecting
2354 production knobs which might alter system functionality.
2358 config BITFIELD_KUNIT
2359 tristate "KUnit test bitfield functions at runtime"
2362 Enable this option to test the bitfield functions at boot.
2364 KUnit tests run during boot and output the results to the debug log
2365 in TAP format (http://testanything.org/). Only useful for kernel devs
2366 running the KUnit test harness, and not intended for inclusion into a
2369 For more information on KUnit and unit tests in general please refer
2370 to the KUnit documentation in Documentation/dev-tools/kunit/.
2374 config RESOURCE_KUNIT_TEST
2375 tristate "KUnit test for resource API"
2378 This builds the resource API unit test.
2379 Tests the logic of API provided by resource.c and ioport.h.
2380 For more information on KUnit and unit tests in general please refer
2381 to the KUnit documentation in Documentation/dev-tools/kunit/.
2385 config SYSCTL_KUNIT_TEST
2386 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2388 default KUNIT_ALL_TESTS
2390 This builds the proc sysctl unit test, which runs on boot.
2391 Tests the API contract and implementation correctness of sysctl.
2392 For more information on KUnit and unit tests in general please refer
2393 to the KUnit documentation in Documentation/dev-tools/kunit/.
2397 config LIST_KUNIT_TEST
2398 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2400 default KUNIT_ALL_TESTS
2402 This builds the linked list KUnit test suite.
2403 It tests that the API and basic functionality of the list_head type
2404 and associated macros.
2406 KUnit tests run during boot and output the results to the debug log
2407 in TAP format (https://testanything.org/). Only useful for kernel devs
2408 running the KUnit test harness, and not intended for inclusion into a
2411 For more information on KUnit and unit tests in general please refer
2412 to the KUnit documentation in Documentation/dev-tools/kunit/.
2416 config LINEAR_RANGES_TEST
2417 tristate "KUnit test for linear_ranges"
2419 select LINEAR_RANGES
2421 This builds the linear_ranges unit test, which runs on boot.
2422 Tests the linear_ranges logic correctness.
2423 For more information on KUnit and unit tests in general please refer
2424 to the KUnit documentation in Documentation/dev-tools/kunit/.
2428 config CMDLINE_KUNIT_TEST
2429 tristate "KUnit test for cmdline API"
2432 This builds the cmdline API unit test.
2433 Tests the logic of API provided by cmdline.c.
2434 For more information on KUnit and unit tests in general please refer
2435 to the KUnit documentation in Documentation/dev-tools/kunit/.
2440 tristate "KUnit test for bits.h"
2443 This builds the bits unit test.
2444 Tests the logic of macros defined in bits.h.
2445 For more information on KUnit and unit tests in general please refer
2446 to the KUnit documentation in Documentation/dev-tools/kunit/.
2450 config SLUB_KUNIT_TEST
2451 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2452 depends on SLUB_DEBUG && KUNIT
2453 default KUNIT_ALL_TESTS
2455 This builds SLUB allocator unit test.
2456 Tests SLUB cache debugging functionality.
2457 For more information on KUnit and unit tests in general please refer
2458 to the KUnit documentation in Documentation/dev-tools/kunit/.
2462 config RATIONAL_KUNIT_TEST
2463 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2464 depends on KUNIT && RATIONAL
2465 default KUNIT_ALL_TESTS
2467 This builds the rational math unit test.
2468 For more information on KUnit and unit tests in general please refer
2469 to the KUnit documentation in Documentation/dev-tools/kunit/.
2473 config MEMCPY_KUNIT_TEST
2474 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2476 default KUNIT_ALL_TESTS
2478 Builds unit tests for memcpy(), memmove(), and memset() functions.
2479 For more information on KUnit and unit tests in general please refer
2480 to the KUnit documentation in Documentation/dev-tools/kunit/.
2485 tristate "udelay test driver"
2487 This builds the "udelay_test" module that helps to make sure
2488 that udelay() is working properly.
2492 config TEST_STATIC_KEYS
2493 tristate "Test static keys"
2496 Test the static key interfaces.
2501 tristate "kmod stress tester"
2503 depends on NETDEVICES && NET_CORE && INET # for TUN
2510 Test the kernel's module loading mechanism: kmod. kmod implements
2511 support to load modules using the Linux kernel's usermode helper.
2512 This test provides a series of tests against kmod.
2514 Although technically you can either build test_kmod as a module or
2515 into the kernel we disallow building it into the kernel since
2516 it stress tests request_module() and this will very likely cause
2517 some issues by taking over precious threads available from other
2518 module load requests, ultimately this could be fatal.
2522 tools/testing/selftests/kmod/kmod.sh --help
2526 config TEST_DEBUG_VIRTUAL
2527 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2528 depends on DEBUG_VIRTUAL
2530 Test the kernel's ability to detect incorrect calls to
2531 virt_to_phys() done against the non-linear part of the
2532 kernel's virtual address map.
2536 config TEST_MEMCAT_P
2537 tristate "Test memcat_p() helper function"
2539 Test the memcat_p() helper for correctly merging two
2540 pointer arrays together.
2544 config TEST_LIVEPATCH
2545 tristate "Test livepatching"
2547 depends on DYNAMIC_DEBUG
2548 depends on LIVEPATCH
2551 Test kernel livepatching features for correctness. The tests will
2552 load test modules that will be livepatched in various scenarios.
2554 To run all the livepatching tests:
2556 make -C tools/testing/selftests TARGETS=livepatch run_tests
2558 Alternatively, individual tests may be invoked:
2560 tools/testing/selftests/livepatch/test-callbacks.sh
2561 tools/testing/selftests/livepatch/test-livepatch.sh
2562 tools/testing/selftests/livepatch/test-shadow-vars.sh
2567 tristate "Perform selftest on object aggreration manager"
2571 Enable this option to test object aggregation manager on boot
2575 config TEST_STACKINIT
2576 tristate "Test level of stack variable initialization"
2578 Test if the kernel is zero-initializing stack variables and
2579 padding. Coverage is controlled by compiler flags,
2580 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2581 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2586 tristate "Test heap/page initialization"
2588 Test if the kernel is zero-initializing heap and page allocations.
2589 This can be useful to test init_on_alloc and init_on_free features.
2594 tristate "Test HMM (Heterogeneous Memory Management)"
2595 depends on TRANSPARENT_HUGEPAGE
2596 depends on DEVICE_PRIVATE
2600 This is a pseudo device driver solely for testing HMM.
2601 Say M here if you want to build the HMM test module.
2602 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2606 config TEST_FREE_PAGES
2607 tristate "Test freeing pages"
2609 Test that a memory leak does not occur due to a race between
2610 freeing a block of pages and a speculative page reference.
2611 Loading this module is safe if your kernel has the bug fixed.
2612 If the bug is not fixed, it will leak gigabytes of memory and
2613 probably OOM your system.
2616 tristate "Test floating point operations in kernel space"
2617 depends on X86 && !KCOV_INSTRUMENT_ALL
2619 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2620 which will trigger a sequence of floating point operations. This is used
2621 for self-testing floating point control register setting in
2626 config TEST_CLOCKSOURCE_WATCHDOG
2627 tristate "Test clocksource watchdog in kernel space"
2628 depends on CLOCKSOURCE_WATCHDOG
2630 Enable this option to create a kernel module that will trigger
2631 a test of the clocksource watchdog. This module may be loaded
2632 via modprobe or insmod in which case it will run upon being
2633 loaded, or it may be built in, in which case it will run
2638 endif # RUNTIME_TESTING_MENU
2640 config ARCH_USE_MEMTEST
2643 An architecture should select this when it uses early_memtest()
2644 during boot process.
2648 depends on ARCH_USE_MEMTEST
2650 This option adds a kernel parameter 'memtest', which allows memtest
2651 to be set and executed.
2652 memtest=0, mean disabled; -- default
2653 memtest=1, mean do 1 test pattern;
2655 memtest=17, mean do 17 test patterns.
2656 If you are unsure how to answer this question, answer N.
2660 config HYPERV_TESTING
2661 bool "Microsoft Hyper-V driver testing"
2663 depends on HYPERV && DEBUG_FS
2665 Select this option to enable Hyper-V vmbus testing.
2667 endmenu # "Kernel Testing and Coverage"
2669 source "Documentation/Kconfig"
2671 endmenu # Kernel hacking
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