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.
603 menu "Memory Debugging"
605 source "mm/Kconfig.debug"
608 bool "Debug object operations"
609 depends on DEBUG_KERNEL
611 If you say Y here, additional code will be inserted into the
612 kernel to track the life time of various objects and validate
613 the operations on those objects.
615 config DEBUG_OBJECTS_SELFTEST
616 bool "Debug objects selftest"
617 depends on DEBUG_OBJECTS
619 This enables the selftest of the object debug code.
621 config DEBUG_OBJECTS_FREE
622 bool "Debug objects in freed memory"
623 depends on DEBUG_OBJECTS
625 This enables checks whether a k/v free operation frees an area
626 which contains an object which has not been deactivated
627 properly. This can make kmalloc/kfree-intensive workloads
630 config DEBUG_OBJECTS_TIMERS
631 bool "Debug timer objects"
632 depends on DEBUG_OBJECTS
634 If you say Y here, additional code will be inserted into the
635 timer routines to track the life time of timer objects and
636 validate the timer operations.
638 config DEBUG_OBJECTS_WORK
639 bool "Debug work objects"
640 depends on DEBUG_OBJECTS
642 If you say Y here, additional code will be inserted into the
643 work queue routines to track the life time of work objects and
644 validate the work operations.
646 config DEBUG_OBJECTS_RCU_HEAD
647 bool "Debug RCU callbacks objects"
648 depends on DEBUG_OBJECTS
650 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
652 config DEBUG_OBJECTS_PERCPU_COUNTER
653 bool "Debug percpu counter objects"
654 depends on DEBUG_OBJECTS
656 If you say Y here, additional code will be inserted into the
657 percpu counter routines to track the life time of percpu counter
658 objects and validate the percpu counter operations.
660 config DEBUG_OBJECTS_ENABLE_DEFAULT
661 int "debug_objects bootup default value (0-1)"
664 depends on DEBUG_OBJECTS
666 Debug objects boot parameter default value
669 bool "Debug slab memory allocations"
670 depends on DEBUG_KERNEL && SLAB
672 Say Y here to have the kernel do limited verification on memory
673 allocation as well as poisoning memory on free to catch use of freed
674 memory. This can make kmalloc/kfree-intensive workloads much slower.
677 bool "SLUB debugging on by default"
678 depends on SLUB && SLUB_DEBUG
681 Boot with debugging on by default. SLUB boots by default with
682 the runtime debug capabilities switched off. Enabling this is
683 equivalent to specifying the "slub_debug" parameter on boot.
684 There is no support for more fine grained debug control like
685 possible with slub_debug=xxx. SLUB debugging may be switched
686 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
691 bool "Enable SLUB performance statistics"
692 depends on SLUB && SYSFS
694 SLUB statistics are useful to debug SLUBs allocation behavior in
695 order find ways to optimize the allocator. This should never be
696 enabled for production use since keeping statistics slows down
697 the allocator by a few percentage points. The slabinfo command
698 supports the determination of the most active slabs to figure
699 out which slabs are relevant to a particular load.
700 Try running: slabinfo -DA
702 config HAVE_DEBUG_KMEMLEAK
705 config DEBUG_KMEMLEAK
706 bool "Kernel memory leak detector"
707 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
709 select STACKTRACE if STACKTRACE_SUPPORT
713 Say Y here if you want to enable the memory leak
714 detector. The memory allocation/freeing is traced in a way
715 similar to the Boehm's conservative garbage collector, the
716 difference being that the orphan objects are not freed but
717 only shown in /sys/kernel/debug/kmemleak. Enabling this
718 feature will introduce an overhead to memory
719 allocations. See Documentation/dev-tools/kmemleak.rst for more
722 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
723 of finding leaks due to the slab objects poisoning.
725 In order to access the kmemleak file, debugfs needs to be
726 mounted (usually at /sys/kernel/debug).
728 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
729 int "Kmemleak memory pool size"
730 depends on DEBUG_KMEMLEAK
734 Kmemleak must track all the memory allocations to avoid
735 reporting false positives. Since memory may be allocated or
736 freed before kmemleak is fully initialised, use a static pool
737 of metadata objects to track such callbacks. After kmemleak is
738 fully initialised, this memory pool acts as an emergency one
739 if slab allocations fail.
741 config DEBUG_KMEMLEAK_TEST
742 tristate "Simple test for the kernel memory leak detector"
743 depends on DEBUG_KMEMLEAK && m
745 This option enables a module that explicitly leaks memory.
749 config DEBUG_KMEMLEAK_DEFAULT_OFF
750 bool "Default kmemleak to off"
751 depends on DEBUG_KMEMLEAK
753 Say Y here to disable kmemleak by default. It can then be enabled
754 on the command line via kmemleak=on.
756 config DEBUG_KMEMLEAK_AUTO_SCAN
757 bool "Enable kmemleak auto scan thread on boot up"
759 depends on DEBUG_KMEMLEAK
761 Depending on the cpu, kmemleak scan may be cpu intensive and can
762 stall user tasks at times. This option enables/disables automatic
763 kmemleak scan at boot up.
765 Say N here to disable kmemleak auto scan thread to stop automatic
766 scanning. Disabling this option disables automatic reporting of
771 config DEBUG_STACK_USAGE
772 bool "Stack utilization instrumentation"
773 depends on DEBUG_KERNEL && !IA64
775 Enables the display of the minimum amount of free stack which each
776 task has ever had available in the sysrq-T and sysrq-P debug output.
778 This option will slow down process creation somewhat.
780 config SCHED_STACK_END_CHECK
781 bool "Detect stack corruption on calls to schedule()"
782 depends on DEBUG_KERNEL
785 This option checks for a stack overrun on calls to schedule().
786 If the stack end location is found to be over written always panic as
787 the content of the corrupted region can no longer be trusted.
788 This is to ensure no erroneous behaviour occurs which could result in
789 data corruption or a sporadic crash at a later stage once the region
790 is examined. The runtime overhead introduced is minimal.
792 config ARCH_HAS_DEBUG_VM_PGTABLE
795 An architecture should select this when it can successfully
796 build and run DEBUG_VM_PGTABLE.
800 depends on DEBUG_KERNEL
802 Enable this to turn on extended checks in the virtual-memory system
803 that may impact performance.
807 config DEBUG_VM_VMACACHE
808 bool "Debug VMA caching"
811 Enable this to turn on VMA caching debug information. Doing so
812 can cause significant overhead, so only enable it in non-production
818 bool "Debug VM red-black trees"
821 Enable VM red-black tree debugging information and extra validations.
825 config DEBUG_VM_PGFLAGS
826 bool "Debug page-flags operations"
829 Enables extra validation on page flags operations.
833 config DEBUG_VM_PGTABLE
834 bool "Debug arch page table for semantics compliance"
836 depends on ARCH_HAS_DEBUG_VM_PGTABLE
837 default y if DEBUG_VM
839 This option provides a debug method which can be used to test
840 architecture page table helper functions on various platforms in
841 verifying if they comply with expected generic MM semantics. This
842 will help architecture code in making sure that any changes or
843 new additions of these helpers still conform to expected
844 semantics of the generic MM. Platforms will have to opt in for
845 this through ARCH_HAS_DEBUG_VM_PGTABLE.
849 config ARCH_HAS_DEBUG_VIRTUAL
853 bool "Debug VM translations"
854 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
856 Enable some costly sanity checks in virtual to page code. This can
857 catch mistakes with virt_to_page() and friends.
861 config DEBUG_NOMMU_REGIONS
862 bool "Debug the global anon/private NOMMU mapping region tree"
863 depends on DEBUG_KERNEL && !MMU
865 This option causes the global tree of anonymous and private mapping
866 regions to be regularly checked for invalid topology.
868 config DEBUG_MEMORY_INIT
869 bool "Debug memory initialisation" if EXPERT
872 Enable this for additional checks during memory initialisation.
873 The sanity checks verify aspects of the VM such as the memory model
874 and other information provided by the architecture. Verbose
875 information will be printed at KERN_DEBUG loglevel depending
876 on the mminit_loglevel= command-line option.
880 config MEMORY_NOTIFIER_ERROR_INJECT
881 tristate "Memory hotplug notifier error injection module"
882 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
884 This option provides the ability to inject artificial errors to
885 memory hotplug notifier chain callbacks. It is controlled through
886 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
888 If the notifier call chain should be failed with some events
889 notified, write the error code to "actions/<notifier event>/error".
891 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
893 # cd /sys/kernel/debug/notifier-error-inject/memory
894 # echo -12 > actions/MEM_GOING_OFFLINE/error
895 # echo offline > /sys/devices/system/memory/memoryXXX/state
896 bash: echo: write error: Cannot allocate memory
898 To compile this code as a module, choose M here: the module will
899 be called memory-notifier-error-inject.
903 config DEBUG_PER_CPU_MAPS
904 bool "Debug access to per_cpu maps"
905 depends on DEBUG_KERNEL
908 Say Y to verify that the per_cpu map being accessed has
909 been set up. This adds a fair amount of code to kernel memory
910 and decreases performance.
914 config DEBUG_KMAP_LOCAL
915 bool "Debug kmap_local temporary mappings"
916 depends on DEBUG_KERNEL && KMAP_LOCAL
918 This option enables additional error checking for the kmap_local
919 infrastructure. Disable for production use.
921 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
924 config DEBUG_KMAP_LOCAL_FORCE_MAP
925 bool "Enforce kmap_local temporary mappings"
926 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
928 select DEBUG_KMAP_LOCAL
930 This option enforces temporary mappings through the kmap_local
931 mechanism for non-highmem pages and on non-highmem systems.
932 Disable this for production systems!
935 bool "Highmem debugging"
936 depends on DEBUG_KERNEL && HIGHMEM
937 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
938 select DEBUG_KMAP_LOCAL
940 This option enables additional error checking for high memory
941 systems. Disable for production systems.
943 config HAVE_DEBUG_STACKOVERFLOW
946 config DEBUG_STACKOVERFLOW
947 bool "Check for stack overflows"
948 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
950 Say Y here if you want to check for overflows of kernel, IRQ
951 and exception stacks (if your architecture uses them). This
952 option will show detailed messages if free stack space drops
953 below a certain limit.
955 These kinds of bugs usually occur when call-chains in the
956 kernel get too deep, especially when interrupts are
959 Use this in cases where you see apparently random memory
960 corruption, especially if it appears in 'struct thread_info'
962 If in doubt, say "N".
964 source "lib/Kconfig.kasan"
965 source "lib/Kconfig.kfence"
967 endmenu # "Memory Debugging"
970 bool "Debug shared IRQ handlers"
971 depends on DEBUG_KERNEL
973 Enable this to generate a spurious interrupt just before a shared
974 interrupt handler is deregistered (generating one when registering
975 is currently disabled). Drivers need to handle this correctly. Some
976 don't and need to be caught.
978 menu "Debug Oops, Lockups and Hangs"
983 Say Y here to enable the kernel to panic when it oopses. This
984 has the same effect as setting oops=panic on the kernel command
987 This feature is useful to ensure that the kernel does not do
988 anything erroneous after an oops which could result in data
989 corruption or other issues.
993 config PANIC_ON_OOPS_VALUE
996 default 0 if !PANIC_ON_OOPS
997 default 1 if PANIC_ON_OOPS
1003 Set the timeout value (in seconds) until a reboot occurs when
1004 the kernel panics. If n = 0, then we wait forever. A timeout
1005 value n > 0 will wait n seconds before rebooting, while a timeout
1006 value n < 0 will reboot immediately.
1008 config LOCKUP_DETECTOR
1011 config SOFTLOCKUP_DETECTOR
1012 bool "Detect Soft Lockups"
1013 depends on DEBUG_KERNEL && !S390
1014 select LOCKUP_DETECTOR
1016 Say Y here to enable the kernel to act as a watchdog to detect
1019 Softlockups are bugs that cause the kernel to loop in kernel
1020 mode for more than 20 seconds, without giving other tasks a
1021 chance to run. The current stack trace is displayed upon
1022 detection and the system will stay locked up.
1024 config BOOTPARAM_SOFTLOCKUP_PANIC
1025 bool "Panic (Reboot) On Soft Lockups"
1026 depends on SOFTLOCKUP_DETECTOR
1028 Say Y here to enable the kernel to panic on "soft lockups",
1029 which are bugs that cause the kernel to loop in kernel
1030 mode for more than 20 seconds (configurable using the watchdog_thresh
1031 sysctl), without giving other tasks a chance to run.
1033 The panic can be used in combination with panic_timeout,
1034 to cause the system to reboot automatically after a
1035 lockup has been detected. This feature is useful for
1036 high-availability systems that have uptime guarantees and
1037 where a lockup must be resolved ASAP.
1041 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
1043 depends on SOFTLOCKUP_DETECTOR
1045 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
1046 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
1048 config HARDLOCKUP_DETECTOR_PERF
1050 select SOFTLOCKUP_DETECTOR
1053 # Enables a timestamp based low pass filter to compensate for perf based
1054 # hard lockup detection which runs too fast due to turbo modes.
1056 config HARDLOCKUP_CHECK_TIMESTAMP
1060 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1061 # lockup detector rather than the perf based detector.
1063 config HARDLOCKUP_DETECTOR
1064 bool "Detect Hard Lockups"
1065 depends on DEBUG_KERNEL && !S390
1066 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1067 select LOCKUP_DETECTOR
1068 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1070 Say Y here to enable the kernel to act as a watchdog to detect
1073 Hardlockups are bugs that cause the CPU to loop in kernel mode
1074 for more than 10 seconds, without letting other interrupts have a
1075 chance to run. The current stack trace is displayed upon detection
1076 and the system will stay locked up.
1078 config BOOTPARAM_HARDLOCKUP_PANIC
1079 bool "Panic (Reboot) On Hard Lockups"
1080 depends on HARDLOCKUP_DETECTOR
1082 Say Y here to enable the kernel to panic on "hard lockups",
1083 which are bugs that cause the kernel to loop in kernel
1084 mode with interrupts disabled for more than 10 seconds (configurable
1085 using the watchdog_thresh sysctl).
1089 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
1091 depends on HARDLOCKUP_DETECTOR
1093 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
1094 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
1096 config DETECT_HUNG_TASK
1097 bool "Detect Hung Tasks"
1098 depends on DEBUG_KERNEL
1099 default SOFTLOCKUP_DETECTOR
1101 Say Y here to enable the kernel to detect "hung tasks",
1102 which are bugs that cause the task to be stuck in
1103 uninterruptible "D" state indefinitely.
1105 When a hung task is detected, the kernel will print the
1106 current stack trace (which you should report), but the
1107 task will stay in uninterruptible state. If lockdep is
1108 enabled then all held locks will also be reported. This
1109 feature has negligible overhead.
1111 config DEFAULT_HUNG_TASK_TIMEOUT
1112 int "Default timeout for hung task detection (in seconds)"
1113 depends on DETECT_HUNG_TASK
1116 This option controls the default timeout (in seconds) used
1117 to determine when a task has become non-responsive and should
1120 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1121 sysctl or by writing a value to
1122 /proc/sys/kernel/hung_task_timeout_secs.
1124 A timeout of 0 disables the check. The default is two minutes.
1125 Keeping the default should be fine in most cases.
1127 config BOOTPARAM_HUNG_TASK_PANIC
1128 bool "Panic (Reboot) On Hung Tasks"
1129 depends on DETECT_HUNG_TASK
1131 Say Y here to enable the kernel to panic on "hung tasks",
1132 which are bugs that cause the kernel to leave a task stuck
1133 in uninterruptible "D" state.
1135 The panic can be used in combination with panic_timeout,
1136 to cause the system to reboot automatically after a
1137 hung task has been detected. This feature is useful for
1138 high-availability systems that have uptime guarantees and
1139 where a hung tasks must be resolved ASAP.
1143 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
1145 depends on DETECT_HUNG_TASK
1147 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
1148 default 1 if BOOTPARAM_HUNG_TASK_PANIC
1151 bool "Detect Workqueue Stalls"
1152 depends on DEBUG_KERNEL
1154 Say Y here to enable stall detection on workqueues. If a
1155 worker pool doesn't make forward progress on a pending work
1156 item for over a given amount of time, 30s by default, a
1157 warning message is printed along with dump of workqueue
1158 state. This can be configured through kernel parameter
1159 "workqueue.watchdog_thresh" and its sysfs counterpart.
1162 tristate "Test module to generate lockups"
1165 This builds the "test_lockup" module that helps to make sure
1166 that watchdogs and lockup detectors are working properly.
1168 Depending on module parameters it could emulate soft or hard
1169 lockup, "hung task", or locking arbitrary lock for a long time.
1170 Also it could generate series of lockups with cooling-down periods.
1174 endmenu # "Debug lockups and hangs"
1176 menu "Scheduler Debugging"
1179 bool "Collect scheduler debugging info"
1180 depends on DEBUG_KERNEL && PROC_FS
1183 If you say Y here, the /proc/sched_debug file will be provided
1184 that can help debug the scheduler. The runtime overhead of this
1192 bool "Collect scheduler statistics"
1193 depends on DEBUG_KERNEL && PROC_FS
1196 If you say Y here, additional code will be inserted into the
1197 scheduler and related routines to collect statistics about
1198 scheduler behavior and provide them in /proc/schedstat. These
1199 stats may be useful for both tuning and debugging the scheduler
1200 If you aren't debugging the scheduler or trying to tune a specific
1201 application, you can say N to avoid the very slight overhead
1206 config DEBUG_TIMEKEEPING
1207 bool "Enable extra timekeeping sanity checking"
1209 This option will enable additional timekeeping sanity checks
1210 which may be helpful when diagnosing issues where timekeeping
1211 problems are suspected.
1213 This may include checks in the timekeeping hotpaths, so this
1214 option may have a (very small) performance impact to some
1219 config DEBUG_PREEMPT
1220 bool "Debug preemptible kernel"
1221 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1224 If you say Y here then the kernel will use a debug variant of the
1225 commonly used smp_processor_id() function and will print warnings
1226 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1227 will detect preemption count underflows.
1229 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1231 config LOCK_DEBUGGING_SUPPORT
1233 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1236 config PROVE_LOCKING
1237 bool "Lock debugging: prove locking correctness"
1238 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1240 select DEBUG_SPINLOCK
1241 select DEBUG_MUTEXES if !PREEMPT_RT
1242 select DEBUG_RT_MUTEXES if RT_MUTEXES
1244 select DEBUG_WW_MUTEX_SLOWPATH
1245 select DEBUG_LOCK_ALLOC
1246 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1247 select TRACE_IRQFLAGS
1250 This feature enables the kernel to prove that all locking
1251 that occurs in the kernel runtime is mathematically
1252 correct: that under no circumstance could an arbitrary (and
1253 not yet triggered) combination of observed locking
1254 sequences (on an arbitrary number of CPUs, running an
1255 arbitrary number of tasks and interrupt contexts) cause a
1258 In short, this feature enables the kernel to report locking
1259 related deadlocks before they actually occur.
1261 The proof does not depend on how hard and complex a
1262 deadlock scenario would be to trigger: how many
1263 participant CPUs, tasks and irq-contexts would be needed
1264 for it to trigger. The proof also does not depend on
1265 timing: if a race and a resulting deadlock is possible
1266 theoretically (no matter how unlikely the race scenario
1267 is), it will be proven so and will immediately be
1268 reported by the kernel (once the event is observed that
1269 makes the deadlock theoretically possible).
1271 If a deadlock is impossible (i.e. the locking rules, as
1272 observed by the kernel, are mathematically correct), the
1273 kernel reports nothing.
1275 NOTE: this feature can also be enabled for rwlocks, mutexes
1276 and rwsems - in which case all dependencies between these
1277 different locking variants are observed and mapped too, and
1278 the proof of observed correctness is also maintained for an
1279 arbitrary combination of these separate locking variants.
1281 For more details, see Documentation/locking/lockdep-design.rst.
1283 config PROVE_RAW_LOCK_NESTING
1284 bool "Enable raw_spinlock - spinlock nesting checks"
1285 depends on PROVE_LOCKING
1288 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1289 that the lock nesting rules for PREEMPT_RT enabled kernels are
1292 NOTE: There are known nesting problems. So if you enable this
1293 option expect lockdep splats until these problems have been fully
1294 addressed which is work in progress. This config switch allows to
1295 identify and analyze these problems. It will be removed and the
1296 check permanently enabled once the main issues have been fixed.
1298 If unsure, select N.
1301 bool "Lock usage statistics"
1302 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1304 select DEBUG_SPINLOCK
1305 select DEBUG_MUTEXES if !PREEMPT_RT
1306 select DEBUG_RT_MUTEXES if RT_MUTEXES
1307 select DEBUG_LOCK_ALLOC
1310 This feature enables tracking lock contention points
1312 For more details, see Documentation/locking/lockstat.rst
1314 This also enables lock events required by "perf lock",
1316 If you want to use "perf lock", you also need to turn on
1317 CONFIG_EVENT_TRACING.
1319 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1320 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1322 config DEBUG_RT_MUTEXES
1323 bool "RT Mutex debugging, deadlock detection"
1324 depends on DEBUG_KERNEL && RT_MUTEXES
1326 This allows rt mutex semantics violations and rt mutex related
1327 deadlocks (lockups) to be detected and reported automatically.
1329 config DEBUG_SPINLOCK
1330 bool "Spinlock and rw-lock debugging: basic checks"
1331 depends on DEBUG_KERNEL
1332 select UNINLINE_SPIN_UNLOCK
1334 Say Y here and build SMP to catch missing spinlock initialization
1335 and certain other kinds of spinlock errors commonly made. This is
1336 best used in conjunction with the NMI watchdog so that spinlock
1337 deadlocks are also debuggable.
1339 config DEBUG_MUTEXES
1340 bool "Mutex debugging: basic checks"
1341 depends on DEBUG_KERNEL && !PREEMPT_RT
1343 This feature allows mutex semantics violations to be detected and
1346 config DEBUG_WW_MUTEX_SLOWPATH
1347 bool "Wait/wound mutex debugging: Slowpath testing"
1348 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1349 select DEBUG_LOCK_ALLOC
1350 select DEBUG_SPINLOCK
1351 select DEBUG_MUTEXES if !PREEMPT_RT
1352 select DEBUG_RT_MUTEXES if PREEMPT_RT
1354 This feature enables slowpath testing for w/w mutex users by
1355 injecting additional -EDEADLK wound/backoff cases. Together with
1356 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1357 will test all possible w/w mutex interface abuse with the
1358 exception of simply not acquiring all the required locks.
1359 Note that this feature can introduce significant overhead, so
1360 it really should not be enabled in a production or distro kernel,
1361 even a debug kernel. If you are a driver writer, enable it. If
1362 you are a distro, do not.
1365 bool "RW Semaphore debugging: basic checks"
1366 depends on DEBUG_KERNEL
1368 This debugging feature allows mismatched rw semaphore locks
1369 and unlocks to be detected and reported.
1371 config DEBUG_LOCK_ALLOC
1372 bool "Lock debugging: detect incorrect freeing of live locks"
1373 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1374 select DEBUG_SPINLOCK
1375 select DEBUG_MUTEXES if !PREEMPT_RT
1376 select DEBUG_RT_MUTEXES if RT_MUTEXES
1379 This feature will check whether any held lock (spinlock, rwlock,
1380 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1381 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1382 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1383 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1384 held during task exit.
1388 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1393 config LOCKDEP_SMALL
1397 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1398 depends on LOCKDEP && !LOCKDEP_SMALL
1402 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1404 config LOCKDEP_CHAINS_BITS
1405 int "Bitsize for MAX_LOCKDEP_CHAINS"
1406 depends on LOCKDEP && !LOCKDEP_SMALL
1410 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1412 config LOCKDEP_STACK_TRACE_BITS
1413 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1414 depends on LOCKDEP && !LOCKDEP_SMALL
1418 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1420 config LOCKDEP_STACK_TRACE_HASH_BITS
1421 int "Bitsize for STACK_TRACE_HASH_SIZE"
1422 depends on LOCKDEP && !LOCKDEP_SMALL
1426 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1428 config LOCKDEP_CIRCULAR_QUEUE_BITS
1429 int "Bitsize for elements in circular_queue struct"
1434 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1436 config DEBUG_LOCKDEP
1437 bool "Lock dependency engine debugging"
1438 depends on DEBUG_KERNEL && LOCKDEP
1439 select DEBUG_IRQFLAGS
1441 If you say Y here, the lock dependency engine will do
1442 additional runtime checks to debug itself, at the price
1443 of more runtime overhead.
1445 config DEBUG_ATOMIC_SLEEP
1446 bool "Sleep inside atomic section checking"
1447 select PREEMPT_COUNT
1448 depends on DEBUG_KERNEL
1449 depends on !ARCH_NO_PREEMPT
1451 If you say Y here, various routines which may sleep will become very
1452 noisy if they are called inside atomic sections: when a spinlock is
1453 held, inside an rcu read side critical section, inside preempt disabled
1454 sections, inside an interrupt, etc...
1456 config DEBUG_LOCKING_API_SELFTESTS
1457 bool "Locking API boot-time self-tests"
1458 depends on DEBUG_KERNEL
1460 Say Y here if you want the kernel to run a short self-test during
1461 bootup. The self-test checks whether common types of locking bugs
1462 are detected by debugging mechanisms or not. (if you disable
1463 lock debugging then those bugs won't be detected of course.)
1464 The following locking APIs are covered: spinlocks, rwlocks,
1467 config LOCK_TORTURE_TEST
1468 tristate "torture tests for locking"
1469 depends on DEBUG_KERNEL
1472 This option provides a kernel module that runs torture tests
1473 on kernel locking primitives. The kernel module may be built
1474 after the fact on the running kernel to be tested, if desired.
1476 Say Y here if you want kernel locking-primitive torture tests
1477 to be built into the kernel.
1478 Say M if you want these torture tests to build as a module.
1479 Say N if you are unsure.
1481 config WW_MUTEX_SELFTEST
1482 tristate "Wait/wound mutex selftests"
1484 This option provides a kernel module that runs tests on the
1485 on the struct ww_mutex locking API.
1487 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1488 with this test harness.
1490 Say M if you want these self tests to build as a module.
1491 Say N if you are unsure.
1493 config SCF_TORTURE_TEST
1494 tristate "torture tests for smp_call_function*()"
1495 depends on DEBUG_KERNEL
1498 This option provides a kernel module that runs torture tests
1499 on the smp_call_function() family of primitives. The kernel
1500 module may be built after the fact on the running kernel to
1501 be tested, if desired.
1503 config CSD_LOCK_WAIT_DEBUG
1504 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1505 depends on DEBUG_KERNEL
1509 This option enables debug prints when CPUs are slow to respond
1510 to the smp_call_function*() IPI wrappers. These debug prints
1511 include the IPI handler function currently executing (if any)
1512 and relevant stack traces.
1514 endmenu # lock debugging
1516 config TRACE_IRQFLAGS
1517 depends on TRACE_IRQFLAGS_SUPPORT
1520 Enables hooks to interrupt enabling and disabling for
1521 either tracing or lock debugging.
1523 config TRACE_IRQFLAGS_NMI
1525 depends on TRACE_IRQFLAGS
1526 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1528 config DEBUG_IRQFLAGS
1529 bool "Debug IRQ flag manipulation"
1531 Enables checks for potentially unsafe enabling or disabling of
1532 interrupts, such as calling raw_local_irq_restore() when interrupts
1536 bool "Stack backtrace support"
1537 depends on STACKTRACE_SUPPORT
1539 This option causes the kernel to create a /proc/pid/stack for
1540 every process, showing its current stack trace.
1541 It is also used by various kernel debugging features that require
1542 stack trace generation.
1544 config WARN_ALL_UNSEEDED_RANDOM
1545 bool "Warn for all uses of unseeded randomness"
1548 Some parts of the kernel contain bugs relating to their use of
1549 cryptographically secure random numbers before it's actually possible
1550 to generate those numbers securely. This setting ensures that these
1551 flaws don't go unnoticed, by enabling a message, should this ever
1552 occur. This will allow people with obscure setups to know when things
1553 are going wrong, so that they might contact developers about fixing
1556 Unfortunately, on some models of some architectures getting
1557 a fully seeded CRNG is extremely difficult, and so this can
1558 result in dmesg getting spammed for a surprisingly long
1559 time. This is really bad from a security perspective, and
1560 so architecture maintainers really need to do what they can
1561 to get the CRNG seeded sooner after the system is booted.
1562 However, since users cannot do anything actionable to
1563 address this, by default the kernel will issue only a single
1564 warning for the first use of unseeded randomness.
1566 Say Y here if you want to receive warnings for all uses of
1567 unseeded randomness. This will be of use primarily for
1568 those developers interested in improving the security of
1569 Linux kernels running on their architecture (or
1572 config DEBUG_KOBJECT
1573 bool "kobject debugging"
1574 depends on DEBUG_KERNEL
1576 If you say Y here, some extra kobject debugging messages will be sent
1579 config DEBUG_KOBJECT_RELEASE
1580 bool "kobject release debugging"
1581 depends on DEBUG_OBJECTS_TIMERS
1583 kobjects are reference counted objects. This means that their
1584 last reference count put is not predictable, and the kobject can
1585 live on past the point at which a driver decides to drop it's
1586 initial reference to the kobject gained on allocation. An
1587 example of this would be a struct device which has just been
1590 However, some buggy drivers assume that after such an operation,
1591 the memory backing the kobject can be immediately freed. This
1592 goes completely against the principles of a refcounted object.
1594 If you say Y here, the kernel will delay the release of kobjects
1595 on the last reference count to improve the visibility of this
1596 kind of kobject release bug.
1598 config HAVE_DEBUG_BUGVERBOSE
1601 menu "Debug kernel data structures"
1604 bool "Debug linked list manipulation"
1605 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1607 Enable this to turn on extended checks in the linked-list
1613 bool "Debug priority linked list manipulation"
1614 depends on DEBUG_KERNEL
1616 Enable this to turn on extended checks in the priority-ordered
1617 linked-list (plist) walking routines. This checks the entire
1618 list multiple times during each manipulation.
1623 bool "Debug SG table operations"
1624 depends on DEBUG_KERNEL
1626 Enable this to turn on checks on scatter-gather tables. This can
1627 help find problems with drivers that do not properly initialize
1632 config DEBUG_NOTIFIERS
1633 bool "Debug notifier call chains"
1634 depends on DEBUG_KERNEL
1636 Enable this to turn on sanity checking for notifier call chains.
1637 This is most useful for kernel developers to make sure that
1638 modules properly unregister themselves from notifier chains.
1639 This is a relatively cheap check but if you care about maximum
1642 config BUG_ON_DATA_CORRUPTION
1643 bool "Trigger a BUG when data corruption is detected"
1646 Select this option if the kernel should BUG when it encounters
1647 data corruption in kernel memory structures when they get checked
1654 config DEBUG_CREDENTIALS
1655 bool "Debug credential management"
1656 depends on DEBUG_KERNEL
1658 Enable this to turn on some debug checking for credential
1659 management. The additional code keeps track of the number of
1660 pointers from task_structs to any given cred struct, and checks to
1661 see that this number never exceeds the usage count of the cred
1664 Furthermore, if SELinux is enabled, this also checks that the
1665 security pointer in the cred struct is never seen to be invalid.
1669 source "kernel/rcu/Kconfig.debug"
1671 config DEBUG_WQ_FORCE_RR_CPU
1672 bool "Force round-robin CPU selection for unbound work items"
1673 depends on DEBUG_KERNEL
1676 Workqueue used to implicitly guarantee that work items queued
1677 without explicit CPU specified are put on the local CPU. This
1678 guarantee is no longer true and while local CPU is still
1679 preferred work items may be put on foreign CPUs. Kernel
1680 parameter "workqueue.debug_force_rr_cpu" is added to force
1681 round-robin CPU selection to flush out usages which depend on the
1682 now broken guarantee. This config option enables the debug
1683 feature by default. When enabled, memory and cache locality will
1686 config CPU_HOTPLUG_STATE_CONTROL
1687 bool "Enable CPU hotplug state control"
1688 depends on DEBUG_KERNEL
1689 depends on HOTPLUG_CPU
1692 Allows to write steps between "offline" and "online" to the CPUs
1693 sysfs target file so states can be stepped granular. This is a debug
1694 option for now as the hotplug machinery cannot be stopped and
1695 restarted at arbitrary points yet.
1697 Say N if your are unsure.
1700 bool "Latency measuring infrastructure"
1701 depends on DEBUG_KERNEL
1702 depends on STACKTRACE_SUPPORT
1704 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1710 Enable this option if you want to use the LatencyTOP tool
1711 to find out which userspace is blocking on what kernel operations.
1713 source "kernel/trace/Kconfig"
1715 config PROVIDE_OHCI1394_DMA_INIT
1716 bool "Remote debugging over FireWire early on boot"
1717 depends on PCI && X86
1719 If you want to debug problems which hang or crash the kernel early
1720 on boot and the crashing machine has a FireWire port, you can use
1721 this feature to remotely access the memory of the crashed machine
1722 over FireWire. This employs remote DMA as part of the OHCI1394
1723 specification which is now the standard for FireWire controllers.
1725 With remote DMA, you can monitor the printk buffer remotely using
1726 firescope and access all memory below 4GB using fireproxy from gdb.
1727 Even controlling a kernel debugger is possible using remote DMA.
1731 If ohci1394_dma=early is used as boot parameter, it will initialize
1732 all OHCI1394 controllers which are found in the PCI config space.
1734 As all changes to the FireWire bus such as enabling and disabling
1735 devices cause a bus reset and thereby disable remote DMA for all
1736 devices, be sure to have the cable plugged and FireWire enabled on
1737 the debugging host before booting the debug target for debugging.
1739 This code (~1k) is freed after boot. By then, the firewire stack
1740 in charge of the OHCI-1394 controllers should be used instead.
1742 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1744 source "samples/Kconfig"
1746 config ARCH_HAS_DEVMEM_IS_ALLOWED
1749 config STRICT_DEVMEM
1750 bool "Filter access to /dev/mem"
1751 depends on MMU && DEVMEM
1752 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1753 default y if PPC || X86 || ARM64
1755 If this option is disabled, you allow userspace (root) access to all
1756 of memory, including kernel and userspace memory. Accidental
1757 access to this is obviously disastrous, but specific access can
1758 be used by people debugging the kernel. Note that with PAT support
1759 enabled, even in this case there are restrictions on /dev/mem
1760 use due to the cache aliasing requirements.
1762 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1763 file only allows userspace access to PCI space and the BIOS code and
1764 data regions. This is sufficient for dosemu and X and all common
1769 config IO_STRICT_DEVMEM
1770 bool "Filter I/O access to /dev/mem"
1771 depends on STRICT_DEVMEM
1773 If this option is disabled, you allow userspace (root) access to all
1774 io-memory regardless of whether a driver is actively using that
1775 range. Accidental access to this is obviously disastrous, but
1776 specific access can be used by people debugging kernel drivers.
1778 If this option is switched on, the /dev/mem file only allows
1779 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1780 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1781 if the driver using a given range cannot be disabled.
1785 menu "$(SRCARCH) Debugging"
1787 source "arch/$(SRCARCH)/Kconfig.debug"
1791 menu "Kernel Testing and Coverage"
1793 source "lib/kunit/Kconfig"
1795 config NOTIFIER_ERROR_INJECTION
1796 tristate "Notifier error injection"
1797 depends on DEBUG_KERNEL
1800 This option provides the ability to inject artificial errors to
1801 specified notifier chain callbacks. It is useful to test the error
1802 handling of notifier call chain failures.
1806 config PM_NOTIFIER_ERROR_INJECT
1807 tristate "PM notifier error injection module"
1808 depends on PM && NOTIFIER_ERROR_INJECTION
1809 default m if PM_DEBUG
1811 This option provides the ability to inject artificial errors to
1812 PM notifier chain callbacks. It is controlled through debugfs
1813 interface /sys/kernel/debug/notifier-error-inject/pm
1815 If the notifier call chain should be failed with some events
1816 notified, write the error code to "actions/<notifier event>/error".
1818 Example: Inject PM suspend error (-12 = -ENOMEM)
1820 # cd /sys/kernel/debug/notifier-error-inject/pm/
1821 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1822 # echo mem > /sys/power/state
1823 bash: echo: write error: Cannot allocate memory
1825 To compile this code as a module, choose M here: the module will
1826 be called pm-notifier-error-inject.
1830 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1831 tristate "OF reconfig notifier error injection module"
1832 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1834 This option provides the ability to inject artificial errors to
1835 OF reconfig notifier chain callbacks. It is controlled
1836 through debugfs interface under
1837 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1839 If the notifier call chain should be failed with some events
1840 notified, write the error code to "actions/<notifier event>/error".
1842 To compile this code as a module, choose M here: the module will
1843 be called of-reconfig-notifier-error-inject.
1847 config NETDEV_NOTIFIER_ERROR_INJECT
1848 tristate "Netdev notifier error injection module"
1849 depends on NET && NOTIFIER_ERROR_INJECTION
1851 This option provides the ability to inject artificial errors to
1852 netdevice notifier chain callbacks. It is controlled through debugfs
1853 interface /sys/kernel/debug/notifier-error-inject/netdev
1855 If the notifier call chain should be failed with some events
1856 notified, write the error code to "actions/<notifier event>/error".
1858 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1860 # cd /sys/kernel/debug/notifier-error-inject/netdev
1861 # echo -22 > actions/NETDEV_CHANGEMTU/error
1862 # ip link set eth0 mtu 1024
1863 RTNETLINK answers: Invalid argument
1865 To compile this code as a module, choose M here: the module will
1866 be called netdev-notifier-error-inject.
1870 config FUNCTION_ERROR_INJECTION
1872 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1874 config FAULT_INJECTION
1875 bool "Fault-injection framework"
1876 depends on DEBUG_KERNEL
1878 Provide fault-injection framework.
1879 For more details, see Documentation/fault-injection/.
1882 bool "Fault-injection capability for kmalloc"
1883 depends on FAULT_INJECTION
1884 depends on SLAB || SLUB
1886 Provide fault-injection capability for kmalloc.
1888 config FAIL_PAGE_ALLOC
1889 bool "Fault-injection capability for alloc_pages()"
1890 depends on FAULT_INJECTION
1892 Provide fault-injection capability for alloc_pages().
1894 config FAULT_INJECTION_USERCOPY
1895 bool "Fault injection capability for usercopy functions"
1896 depends on FAULT_INJECTION
1898 Provides fault-injection capability to inject failures
1899 in usercopy functions (copy_from_user(), get_user(), ...).
1901 config FAIL_MAKE_REQUEST
1902 bool "Fault-injection capability for disk IO"
1903 depends on FAULT_INJECTION && BLOCK
1905 Provide fault-injection capability for disk IO.
1907 config FAIL_IO_TIMEOUT
1908 bool "Fault-injection capability for faking disk interrupts"
1909 depends on FAULT_INJECTION && BLOCK
1911 Provide fault-injection capability on end IO handling. This
1912 will make the block layer "forget" an interrupt as configured,
1913 thus exercising the error handling.
1915 Only works with drivers that use the generic timeout handling,
1916 for others it won't do anything.
1919 bool "Fault-injection capability for futexes"
1921 depends on FAULT_INJECTION && FUTEX
1923 Provide fault-injection capability for futexes.
1925 config FAULT_INJECTION_DEBUG_FS
1926 bool "Debugfs entries for fault-injection capabilities"
1927 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1929 Enable configuration of fault-injection capabilities via debugfs.
1931 config FAIL_FUNCTION
1932 bool "Fault-injection capability for functions"
1933 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1935 Provide function-based fault-injection capability.
1936 This will allow you to override a specific function with a return
1937 with given return value. As a result, function caller will see
1938 an error value and have to handle it. This is useful to test the
1939 error handling in various subsystems.
1941 config FAIL_MMC_REQUEST
1942 bool "Fault-injection capability for MMC IO"
1943 depends on FAULT_INJECTION_DEBUG_FS && MMC
1945 Provide fault-injection capability for MMC IO.
1946 This will make the mmc core return data errors. This is
1947 useful to test the error handling in the mmc block device
1948 and to test how the mmc host driver handles retries from
1952 bool "Fault-injection capability for SunRPC"
1953 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1955 Provide fault-injection capability for SunRPC and
1958 config FAULT_INJECTION_STACKTRACE_FILTER
1959 bool "stacktrace filter for fault-injection capabilities"
1960 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1963 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1965 Provide stacktrace filter for fault-injection capabilities
1967 config ARCH_HAS_KCOV
1970 An architecture should select this when it can successfully
1971 build and run with CONFIG_KCOV. This typically requires
1972 disabling instrumentation for some early boot code.
1974 config CC_HAS_SANCOV_TRACE_PC
1975 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1979 bool "Code coverage for fuzzing"
1980 depends on ARCH_HAS_KCOV
1981 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1983 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1985 KCOV exposes kernel code coverage information in a form suitable
1986 for coverage-guided fuzzing (randomized testing).
1988 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1989 different machines and across reboots. If you need stable PC values,
1990 disable RANDOMIZE_BASE.
1992 For more details, see Documentation/dev-tools/kcov.rst.
1994 config KCOV_ENABLE_COMPARISONS
1995 bool "Enable comparison operands collection by KCOV"
1997 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
1999 KCOV also exposes operands of every comparison in the instrumented
2000 code along with operand sizes and PCs of the comparison instructions.
2001 These operands can be used by fuzzing engines to improve the quality
2002 of fuzzing coverage.
2004 config KCOV_INSTRUMENT_ALL
2005 bool "Instrument all code by default"
2009 If you are doing generic system call fuzzing (like e.g. syzkaller),
2010 then you will want to instrument the whole kernel and you should
2011 say y here. If you are doing more targeted fuzzing (like e.g.
2012 filesystem fuzzing with AFL) then you will want to enable coverage
2013 for more specific subsets of files, and should say n here.
2015 config KCOV_IRQ_AREA_SIZE
2016 hex "Size of interrupt coverage collection area in words"
2020 KCOV uses preallocated per-cpu areas to collect coverage from
2021 soft interrupts. This specifies the size of those areas in the
2022 number of unsigned long words.
2024 menuconfig RUNTIME_TESTING_MENU
2025 bool "Runtime Testing"
2028 if RUNTIME_TESTING_MENU
2031 tristate "Linux Kernel Dump Test Tool Module"
2034 This module enables testing of the different dumping mechanisms by
2035 inducing system failures at predefined crash points.
2036 If you don't need it: say N
2037 Choose M here to compile this code as a module. The module will be
2040 Documentation on how to use the module can be found in
2041 Documentation/fault-injection/provoke-crashes.rst
2043 config TEST_LIST_SORT
2044 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2046 default KUNIT_ALL_TESTS
2048 Enable this to turn on 'list_sort()' function test. This test is
2049 executed only once during system boot (so affects only boot time),
2050 or at module load time.
2054 config TEST_MIN_HEAP
2055 tristate "Min heap test"
2056 depends on DEBUG_KERNEL || m
2058 Enable this to turn on min heap function tests. This test is
2059 executed only once during system boot (so affects only boot time),
2060 or at module load time.
2065 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2067 default KUNIT_ALL_TESTS
2069 This option enables the self-test function of 'sort()' at boot,
2070 or at module load time.
2075 tristate "64bit/32bit division and modulo test"
2076 depends on DEBUG_KERNEL || m
2078 Enable this to turn on 'do_div()' function test. This test is
2079 executed only once during system boot (so affects only boot time),
2080 or at module load time.
2084 config KPROBES_SANITY_TEST
2085 tristate "Kprobes sanity tests"
2086 depends on DEBUG_KERNEL
2090 This option provides for testing basic kprobes functionality on
2091 boot. Samples of kprobe and kretprobe are inserted and
2092 verified for functionality.
2094 Say N if you are unsure.
2096 config BACKTRACE_SELF_TEST
2097 tristate "Self test for the backtrace code"
2098 depends on DEBUG_KERNEL
2100 This option provides a kernel module that can be used to test
2101 the kernel stack backtrace code. This option is not useful
2102 for distributions or general kernels, but only for kernel
2103 developers working on architecture code.
2105 Note that if you want to also test saved backtraces, you will
2106 have to enable STACKTRACE as well.
2108 Say N if you are unsure.
2111 tristate "Red-Black tree test"
2112 depends on DEBUG_KERNEL
2114 A benchmark measuring the performance of the rbtree library.
2115 Also includes rbtree invariant checks.
2117 config REED_SOLOMON_TEST
2118 tristate "Reed-Solomon library test"
2119 depends on DEBUG_KERNEL || m
2121 select REED_SOLOMON_ENC16
2122 select REED_SOLOMON_DEC16
2124 This option enables the self-test function of rslib at boot,
2125 or at module load time.
2129 config INTERVAL_TREE_TEST
2130 tristate "Interval tree test"
2131 depends on DEBUG_KERNEL
2132 select INTERVAL_TREE
2134 A benchmark measuring the performance of the interval tree library
2137 tristate "Per cpu operations test"
2138 depends on m && DEBUG_KERNEL
2140 Enable this option to build test module which validates per-cpu
2145 config ATOMIC64_SELFTEST
2146 tristate "Perform an atomic64_t self-test"
2148 Enable this option to test the atomic64_t functions at boot or
2149 at module load time.
2153 config ASYNC_RAID6_TEST
2154 tristate "Self test for hardware accelerated raid6 recovery"
2155 depends on ASYNC_RAID6_RECOV
2158 This is a one-shot self test that permutes through the
2159 recovery of all the possible two disk failure scenarios for a
2160 N-disk array. Recovery is performed with the asynchronous
2161 raid6 recovery routines, and will optionally use an offload
2162 engine if one is available.
2167 tristate "Test functions located in the hexdump module at runtime"
2169 config STRING_SELFTEST
2170 tristate "Test string functions at runtime"
2172 config TEST_STRING_HELPERS
2173 tristate "Test functions located in the string_helpers module at runtime"
2176 tristate "Test strscpy*() family of functions at runtime"
2179 tristate "Test kstrto*() family of functions at runtime"
2182 tristate "Test printf() family of functions at runtime"
2185 tristate "Test scanf() family of functions at runtime"
2188 tristate "Test bitmap_*() family of functions at runtime"
2190 Enable this option to test the bitmap functions at boot.
2195 tristate "Test functions located in the uuid module at runtime"
2198 tristate "Test the XArray code at runtime"
2200 config TEST_OVERFLOW
2201 tristate "Test check_*_overflow() functions at runtime"
2203 config TEST_RHASHTABLE
2204 tristate "Perform selftest on resizable hash table"
2206 Enable this option to test the rhashtable functions at boot.
2211 tristate "Perform selftest on hash functions"
2213 Enable this option to test the kernel's integer (<linux/hash.h>),
2214 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
2215 hash functions on boot (or module load).
2217 This is intended to help people writing architecture-specific
2218 optimized versions. If unsure, say N.
2221 tristate "Perform selftest on IDA functions"
2224 tristate "Perform selftest on priority array manager"
2227 Enable this option to test priority array manager on boot
2232 config TEST_IRQ_TIMINGS
2233 bool "IRQ timings selftest"
2234 depends on IRQ_TIMINGS
2236 Enable this option to test the irq timings code on boot.
2241 tristate "Test module loading with 'hello world' module"
2244 This builds the "test_module" module that emits "Hello, world"
2245 on printk when loaded. It is designed to be used for basic
2246 evaluation of the module loading subsystem (for example when
2247 validating module verification). It lacks any extra dependencies,
2248 and will not normally be loaded by the system unless explicitly
2254 tristate "Test module for compilation of bitops operations"
2257 This builds the "test_bitops" module that is much like the
2258 TEST_LKM module except that it does a basic exercise of the
2259 set/clear_bit macros and get_count_order/long to make sure there are
2260 no compiler warnings from C=1 sparse checker or -Wextra
2261 compilations. It has no dependencies and doesn't run or load unless
2262 explicitly requested by name. for example: modprobe test_bitops.
2267 tristate "Test module for stress/performance analysis of vmalloc allocator"
2272 This builds the "test_vmalloc" module that should be used for
2273 stress and performance analysis. So, any new change for vmalloc
2274 subsystem can be evaluated from performance and stability point
2279 config TEST_USER_COPY
2280 tristate "Test user/kernel boundary protections"
2283 This builds the "test_user_copy" module that runs sanity checks
2284 on the copy_to/from_user infrastructure, making sure basic
2285 user/kernel boundary testing is working. If it fails to load,
2286 a regression has been detected in the user/kernel memory boundary
2292 tristate "Test BPF filter functionality"
2295 This builds the "test_bpf" module that runs various test vectors
2296 against the BPF interpreter or BPF JIT compiler depending on the
2297 current setting. This is in particular useful for BPF JIT compiler
2298 development, but also to run regression tests against changes in
2299 the interpreter code. It also enables test stubs for eBPF maps and
2300 verifier used by user space verifier testsuite.
2304 config TEST_BLACKHOLE_DEV
2305 tristate "Test blackhole netdev functionality"
2308 This builds the "test_blackhole_dev" module that validates the
2309 data path through this blackhole netdev.
2313 config FIND_BIT_BENCHMARK
2314 tristate "Test find_bit functions"
2316 This builds the "test_find_bit" module that measure find_*_bit()
2317 functions performance.
2321 config TEST_FIRMWARE
2322 tristate "Test firmware loading via userspace interface"
2323 depends on FW_LOADER
2325 This builds the "test_firmware" module that creates a userspace
2326 interface for testing firmware loading. This can be used to
2327 control the triggering of firmware loading without needing an
2328 actual firmware-using device. The contents can be rechecked by
2334 tristate "sysctl test driver"
2335 depends on PROC_SYSCTL
2337 This builds the "test_sysctl" module. This driver enables to test the
2338 proc sysctl interfaces available to drivers safely without affecting
2339 production knobs which might alter system functionality.
2343 config BITFIELD_KUNIT
2344 tristate "KUnit test bitfield functions at runtime"
2347 Enable this option to test the bitfield functions at boot.
2349 KUnit tests run during boot and output the results to the debug log
2350 in TAP format (http://testanything.org/). Only useful for kernel devs
2351 running the KUnit test harness, and not intended for inclusion into a
2354 For more information on KUnit and unit tests in general please refer
2355 to the KUnit documentation in Documentation/dev-tools/kunit/.
2359 config RESOURCE_KUNIT_TEST
2360 tristate "KUnit test for resource API"
2363 This builds the resource API unit test.
2364 Tests the logic of API provided by resource.c and ioport.h.
2365 For more information on KUnit and unit tests in general please refer
2366 to the KUnit documentation in Documentation/dev-tools/kunit/.
2370 config SYSCTL_KUNIT_TEST
2371 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2373 default KUNIT_ALL_TESTS
2375 This builds the proc sysctl unit test, which runs on boot.
2376 Tests the API contract and implementation correctness of sysctl.
2377 For more information on KUnit and unit tests in general please refer
2378 to the KUnit documentation in Documentation/dev-tools/kunit/.
2382 config LIST_KUNIT_TEST
2383 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2385 default KUNIT_ALL_TESTS
2387 This builds the linked list KUnit test suite.
2388 It tests that the API and basic functionality of the list_head type
2389 and associated macros.
2391 KUnit tests run during boot and output the results to the debug log
2392 in TAP format (https://testanything.org/). Only useful for kernel devs
2393 running the KUnit test harness, and not intended for inclusion into a
2396 For more information on KUnit and unit tests in general please refer
2397 to the KUnit documentation in Documentation/dev-tools/kunit/.
2401 config LINEAR_RANGES_TEST
2402 tristate "KUnit test for linear_ranges"
2404 select LINEAR_RANGES
2406 This builds the linear_ranges unit test, which runs on boot.
2407 Tests the linear_ranges logic correctness.
2408 For more information on KUnit and unit tests in general please refer
2409 to the KUnit documentation in Documentation/dev-tools/kunit/.
2413 config CMDLINE_KUNIT_TEST
2414 tristate "KUnit test for cmdline API"
2417 This builds the cmdline API unit test.
2418 Tests the logic of API provided by cmdline.c.
2419 For more information on KUnit and unit tests in general please refer
2420 to the KUnit documentation in Documentation/dev-tools/kunit/.
2425 tristate "KUnit test for bits.h"
2428 This builds the bits unit test.
2429 Tests the logic of macros defined in bits.h.
2430 For more information on KUnit and unit tests in general please refer
2431 to the KUnit documentation in Documentation/dev-tools/kunit/.
2435 config SLUB_KUNIT_TEST
2436 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2437 depends on SLUB_DEBUG && KUNIT
2438 default KUNIT_ALL_TESTS
2440 This builds SLUB allocator unit test.
2441 Tests SLUB cache debugging functionality.
2442 For more information on KUnit and unit tests in general please refer
2443 to the KUnit documentation in Documentation/dev-tools/kunit/.
2447 config RATIONAL_KUNIT_TEST
2448 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2449 depends on KUNIT && RATIONAL
2450 default KUNIT_ALL_TESTS
2452 This builds the rational math unit test.
2453 For more information on KUnit and unit tests in general please refer
2454 to the KUnit documentation in Documentation/dev-tools/kunit/.
2458 config MEMCPY_KUNIT_TEST
2459 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2461 default KUNIT_ALL_TESTS
2463 Builds unit tests for memcpy(), memmove(), and memset() functions.
2464 For more information on KUnit and unit tests in general please refer
2465 to the KUnit documentation in Documentation/dev-tools/kunit/.
2470 tristate "udelay test driver"
2472 This builds the "udelay_test" module that helps to make sure
2473 that udelay() is working properly.
2477 config TEST_STATIC_KEYS
2478 tristate "Test static keys"
2481 Test the static key interfaces.
2486 tristate "kmod stress tester"
2488 depends on NETDEVICES && NET_CORE && INET # for TUN
2495 Test the kernel's module loading mechanism: kmod. kmod implements
2496 support to load modules using the Linux kernel's usermode helper.
2497 This test provides a series of tests against kmod.
2499 Although technically you can either build test_kmod as a module or
2500 into the kernel we disallow building it into the kernel since
2501 it stress tests request_module() and this will very likely cause
2502 some issues by taking over precious threads available from other
2503 module load requests, ultimately this could be fatal.
2507 tools/testing/selftests/kmod/kmod.sh --help
2511 config TEST_DEBUG_VIRTUAL
2512 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2513 depends on DEBUG_VIRTUAL
2515 Test the kernel's ability to detect incorrect calls to
2516 virt_to_phys() done against the non-linear part of the
2517 kernel's virtual address map.
2521 config TEST_MEMCAT_P
2522 tristate "Test memcat_p() helper function"
2524 Test the memcat_p() helper for correctly merging two
2525 pointer arrays together.
2529 config TEST_LIVEPATCH
2530 tristate "Test livepatching"
2532 depends on DYNAMIC_DEBUG
2533 depends on LIVEPATCH
2536 Test kernel livepatching features for correctness. The tests will
2537 load test modules that will be livepatched in various scenarios.
2539 To run all the livepatching tests:
2541 make -C tools/testing/selftests TARGETS=livepatch run_tests
2543 Alternatively, individual tests may be invoked:
2545 tools/testing/selftests/livepatch/test-callbacks.sh
2546 tools/testing/selftests/livepatch/test-livepatch.sh
2547 tools/testing/selftests/livepatch/test-shadow-vars.sh
2552 tristate "Perform selftest on object aggreration manager"
2556 Enable this option to test object aggregation manager on boot
2560 config TEST_STACKINIT
2561 tristate "Test level of stack variable initialization"
2563 Test if the kernel is zero-initializing stack variables and
2564 padding. Coverage is controlled by compiler flags,
2565 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2566 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2571 tristate "Test heap/page initialization"
2573 Test if the kernel is zero-initializing heap and page allocations.
2574 This can be useful to test init_on_alloc and init_on_free features.
2579 tristate "Test HMM (Heterogeneous Memory Management)"
2580 depends on TRANSPARENT_HUGEPAGE
2581 depends on DEVICE_PRIVATE
2585 This is a pseudo device driver solely for testing HMM.
2586 Say M here if you want to build the HMM test module.
2587 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2591 config TEST_FREE_PAGES
2592 tristate "Test freeing pages"
2594 Test that a memory leak does not occur due to a race between
2595 freeing a block of pages and a speculative page reference.
2596 Loading this module is safe if your kernel has the bug fixed.
2597 If the bug is not fixed, it will leak gigabytes of memory and
2598 probably OOM your system.
2601 tristate "Test floating point operations in kernel space"
2602 depends on X86 && !KCOV_INSTRUMENT_ALL
2604 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2605 which will trigger a sequence of floating point operations. This is used
2606 for self-testing floating point control register setting in
2611 config TEST_CLOCKSOURCE_WATCHDOG
2612 tristate "Test clocksource watchdog in kernel space"
2613 depends on CLOCKSOURCE_WATCHDOG
2615 Enable this option to create a kernel module that will trigger
2616 a test of the clocksource watchdog. This module may be loaded
2617 via modprobe or insmod in which case it will run upon being
2618 loaded, or it may be built in, in which case it will run
2623 endif # RUNTIME_TESTING_MENU
2625 config ARCH_USE_MEMTEST
2628 An architecture should select this when it uses early_memtest()
2629 during boot process.
2633 depends on ARCH_USE_MEMTEST
2635 This option adds a kernel parameter 'memtest', which allows memtest
2636 to be set and executed.
2637 memtest=0, mean disabled; -- default
2638 memtest=1, mean do 1 test pattern;
2640 memtest=17, mean do 17 test patterns.
2641 If you are unsure how to answer this question, answer N.
2645 config HYPERV_TESTING
2646 bool "Microsoft Hyper-V driver testing"
2648 depends on HYPERV && DEBUG_FS
2650 Select this option to enable Hyper-V vmbus testing.
2652 endmenu # "Kernel Testing and Coverage"
2654 source "Documentation/Kconfig"
2656 endmenu # Kernel hacking
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