1 # SPDX-License-Identifier: GPL-2.0-only
4 menu "printk and dmesg options"
7 bool "Show timing information on printks"
10 Selecting this option causes time stamps of the printk()
11 messages to be added to the output of the syslog() system
12 call and at the console.
14 The timestamp is always recorded internally, and exported
15 to /dev/kmsg. This flag just specifies if the timestamp should
16 be included, not that the timestamp is recorded.
18 The behavior is also controlled by the kernel command line
19 parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
22 bool "Show caller information on printks"
25 Selecting this option causes printk() to add a caller "thread id" (if
26 in task context) or a caller "processor id" (if not in task context)
29 This option is intended for environments where multiple threads
30 concurrently call printk() for many times, for it is difficult to
31 interpret without knowing where these lines (or sometimes individual
32 line which was divided into multiple lines due to race) came from.
34 Since toggling after boot makes the code racy, currently there is
35 no option to enable/disable at the kernel command line parameter or
38 config STACKTRACE_BUILD_ID
39 bool "Show build ID information in stacktraces"
42 Selecting this option adds build ID information for symbols in
43 stacktraces printed with the printk format '%p[SR]b'.
45 This option is intended for distros where debuginfo is not easily
46 accessible but can be downloaded given the build ID of the vmlinux or
47 kernel module where the function is located.
49 config CONSOLE_LOGLEVEL_DEFAULT
50 int "Default console loglevel (1-15)"
54 Default loglevel to determine what will be printed on the console.
56 Setting a default here is equivalent to passing in loglevel=<x> in
57 the kernel bootargs. loglevel=<x> continues to override whatever
58 value is specified here as well.
60 Note: This does not affect the log level of un-prefixed printk()
61 usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
64 config CONSOLE_LOGLEVEL_QUIET
65 int "quiet console loglevel (1-15)"
69 loglevel to use when "quiet" is passed on the kernel commandline.
71 When "quiet" is passed on the kernel commandline this loglevel
72 will be used as the loglevel. IOW passing "quiet" will be the
73 equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
75 config MESSAGE_LOGLEVEL_DEFAULT
76 int "Default message log level (1-7)"
80 Default log level for printk statements with no specified priority.
82 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
83 that are auditing their logs closely may want to set it to a lower
86 Note: This does not affect what message level gets printed on the console
87 by default. To change that, use loglevel=<x> in the kernel bootargs,
88 or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
90 config BOOT_PRINTK_DELAY
91 bool "Delay each boot printk message by N milliseconds"
92 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
94 This build option allows you to read kernel boot messages
95 by inserting a short delay after each one. The delay is
96 specified in milliseconds on the kernel command line,
99 It is likely that you would also need to use "lpj=M" to preset
100 the "loops per jiffie" value.
101 See a previous boot log for the "lpj" value to use for your
102 system, and then set "lpj=M" before setting "boot_delay=N".
103 NOTE: Using this option may adversely affect SMP systems.
104 I.e., processors other than the first one may not boot up.
105 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
106 what it believes to be lockup conditions.
109 bool "Enable dynamic printk() support"
112 depends on (DEBUG_FS || PROC_FS)
113 select DYNAMIC_DEBUG_CORE
116 Compiles debug level messages into the kernel, which would not
117 otherwise be available at runtime. These messages can then be
118 enabled/disabled based on various levels of scope - per source file,
119 function, module, format string, and line number. This mechanism
120 implicitly compiles in all pr_debug() and dev_dbg() calls, which
121 enlarges the kernel text size by about 2%.
123 If a source file is compiled with DEBUG flag set, any
124 pr_debug() calls in it are enabled by default, but can be
125 disabled at runtime as below. Note that DEBUG flag is
126 turned on by many CONFIG_*DEBUG* options.
130 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
131 which is contained in the 'debugfs' filesystem or procfs.
132 Thus, the debugfs or procfs filesystem must first be mounted before
133 making use of this feature.
134 We refer the control file as: <debugfs>/dynamic_debug/control. This
135 file contains a list of the debug statements that can be enabled. The
136 format for each line of the file is:
138 filename:lineno [module]function flags format
140 filename : source file of the debug statement
141 lineno : line number of the debug statement
142 module : module that contains the debug statement
143 function : function that contains the debug statement
144 flags : '=p' means the line is turned 'on' for printing
145 format : the format used for the debug statement
149 nullarbor:~ # cat <debugfs>/dynamic_debug/control
150 # filename:lineno [module]function flags format
151 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
152 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
153 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
157 // enable the message at line 1603 of file svcsock.c
158 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
159 <debugfs>/dynamic_debug/control
161 // enable all the messages in file svcsock.c
162 nullarbor:~ # echo -n 'file svcsock.c +p' >
163 <debugfs>/dynamic_debug/control
165 // enable all the messages in the NFS server module
166 nullarbor:~ # echo -n 'module nfsd +p' >
167 <debugfs>/dynamic_debug/control
169 // enable all 12 messages in the function svc_process()
170 nullarbor:~ # echo -n 'func svc_process +p' >
171 <debugfs>/dynamic_debug/control
173 // disable all 12 messages in the function svc_process()
174 nullarbor:~ # echo -n 'func svc_process -p' >
175 <debugfs>/dynamic_debug/control
177 See Documentation/admin-guide/dynamic-debug-howto.rst for additional
180 config DYNAMIC_DEBUG_CORE
181 bool "Enable core function of dynamic debug support"
183 depends on (DEBUG_FS || PROC_FS)
185 Enable core functional support of dynamic debug. It is useful
186 when you want to tie dynamic debug to your kernel modules with
187 DYNAMIC_DEBUG_MODULE defined for each of them, especially for
188 the case of embedded system where the kernel image size is
189 sensitive for people.
191 config SYMBOLIC_ERRNAME
192 bool "Support symbolic error names in printf"
195 If you say Y here, the kernel's printf implementation will
196 be able to print symbolic error names such as ENOSPC instead
197 of the number 28. It makes the kernel image slightly larger
198 (about 3KB), but can make the kernel logs easier to read.
200 config DEBUG_BUGVERBOSE
201 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
202 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
205 Say Y here to make BUG() panics output the file name and line number
206 of the BUG call as well as the EIP and oops trace. This aids
207 debugging but costs about 70-100K of memory.
209 endmenu # "printk and dmesg options"
211 menu "Compile-time checks and compiler options"
214 bool "Compile the kernel with debug info"
215 depends on DEBUG_KERNEL && !COMPILE_TEST
217 If you say Y here the resulting kernel image will include
218 debugging info resulting in a larger kernel image.
219 This adds debug symbols to the kernel and modules (gcc -g), and
220 is needed if you intend to use kernel crashdump or binary object
221 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
222 Say Y here only if you plan to debug the kernel.
228 config DEBUG_INFO_REDUCED
229 bool "Reduce debugging information"
231 If you say Y here gcc is instructed to generate less debugging
232 information for structure types. This means that tools that
233 need full debugging information (like kgdb or systemtap) won't
234 be happy. But if you merely need debugging information to
235 resolve line numbers there is no loss. Advantage is that
236 build directory object sizes shrink dramatically over a full
237 DEBUG_INFO build and compile times are reduced too.
238 Only works with newer gcc versions.
240 config DEBUG_INFO_COMPRESSED
241 bool "Compressed debugging information"
242 depends on $(cc-option,-gz=zlib)
243 depends on $(ld-option,--compress-debug-sections=zlib)
245 Compress the debug information using zlib. Requires GCC 5.0+ or Clang
246 5.0+, binutils 2.26+, and zlib.
248 Users of dpkg-deb via scripts/package/builddeb may find an increase in
249 size of their debug .deb packages with this config set, due to the
250 debug info being compressed with zlib, then the object files being
251 recompressed with a different compression scheme. But this is still
252 preferable to setting $KDEB_COMPRESS to "none" which would be even
255 config DEBUG_INFO_SPLIT
256 bool "Produce split debuginfo in .dwo files"
257 depends on $(cc-option,-gsplit-dwarf)
259 Generate debug info into separate .dwo files. This significantly
260 reduces the build directory size for builds with DEBUG_INFO,
261 because it stores the information only once on disk in .dwo
262 files instead of multiple times in object files and executables.
263 In addition the debug information is also compressed.
265 Requires recent gcc (4.7+) and recent gdb/binutils.
266 Any tool that packages or reads debug information would need
267 to know about the .dwo files and include them.
268 Incompatible with older versions of ccache.
271 prompt "DWARF version"
273 Which version of DWARF debug info to emit.
275 config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
276 bool "Rely on the toolchain's implicit default DWARF version"
278 The implicit default version of DWARF debug info produced by a
279 toolchain changes over time.
281 This can break consumers of the debug info that haven't upgraded to
282 support newer revisions, and prevent testing newer versions, but
283 those should be less common scenarios.
287 config DEBUG_INFO_DWARF4
288 bool "Generate DWARF Version 4 debuginfo"
290 Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+.
292 If you have consumers of DWARF debug info that are not ready for
293 newer revisions of DWARF, you may wish to choose this or have your
296 config DEBUG_INFO_DWARF5
297 bool "Generate DWARF Version 5 debuginfo"
298 depends on GCC_VERSION >= 50000 || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)))
299 depends on !DEBUG_INFO_BTF
301 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
302 5.0+ accepts the -gdwarf-5 flag but only had partial support for some
303 draft features until 7.0), and gdb 8.0+.
305 Changes to the structure of debug info in Version 5 allow for around
306 15-18% savings in resulting image and debug info section sizes as
307 compared to DWARF Version 4. DWARF Version 5 standardizes previous
308 extensions such as accelerators for symbol indexing and the format
309 for fission (.dwo/.dwp) files. Users may not want to select this
310 config if they rely on tooling that has not yet been updated to
311 support DWARF Version 5.
313 endchoice # "DWARF version"
315 config DEBUG_INFO_BTF
316 bool "Generate BTF typeinfo"
317 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
318 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
320 Generate deduplicated BTF type information from DWARF debug info.
321 Turning this on expects presence of pahole tool, which will convert
322 DWARF type info into equivalent deduplicated BTF type info.
324 config PAHOLE_HAS_SPLIT_BTF
325 def_bool $(success, test `$(PAHOLE) --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/'` -ge "119")
327 config DEBUG_INFO_BTF_MODULES
329 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
331 Generate compact split BTF type information for kernel modules.
334 bool "Provide GDB scripts for kernel debugging"
336 This creates the required links to GDB helper scripts in the
337 build directory. If you load vmlinux into gdb, the helper
338 scripts will be automatically imported by gdb as well, and
339 additional functions are available to analyze a Linux kernel
340 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
346 int "Warn for stack frames larger than"
348 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
349 default 1536 if (!64BIT && PARISC)
350 default 1024 if (!64BIT && !PARISC)
351 default 2048 if 64BIT
353 Tell gcc to warn at build time for stack frames larger than this.
354 Setting this too low will cause a lot of warnings.
355 Setting it to 0 disables the warning.
357 config STRIP_ASM_SYMS
358 bool "Strip assembler-generated symbols during link"
361 Strip internal assembler-generated symbols during a link (symbols
362 that look like '.Lxxx') so they don't pollute the output of
363 get_wchan() and suchlike.
366 bool "Generate readable assembler code"
367 depends on DEBUG_KERNEL
370 Disable some compiler optimizations that tend to generate human unreadable
371 assembler output. This may make the kernel slightly slower, but it helps
372 to keep kernel developers who have to stare a lot at assembler listings
375 config HEADERS_INSTALL
376 bool "Install uapi headers to usr/include"
379 This option will install uapi headers (headers exported to user-space)
380 into the usr/include directory for use during the kernel build.
381 This is unneeded for building the kernel itself, but needed for some
382 user-space program samples. It is also needed by some features such
383 as uapi header sanity checks.
385 config DEBUG_SECTION_MISMATCH
386 bool "Enable full Section mismatch analysis"
389 The section mismatch analysis checks if there are illegal
390 references from one section to another section.
391 During linktime or runtime, some sections are dropped;
392 any use of code/data previously in these sections would
393 most likely result in an oops.
394 In the code, functions and variables are annotated with
395 __init,, etc. (see the full list in include/linux/init.h),
396 which results in the code/data being placed in specific sections.
397 The section mismatch analysis is always performed after a full
398 kernel build, and enabling this option causes the following
399 additional step to occur:
400 - Add the option -fno-inline-functions-called-once to gcc commands.
401 When inlining a function annotated with __init in a non-init
402 function, we would lose the section information and thus
403 the analysis would not catch the illegal reference.
404 This option tells gcc to inline less (but it does result in
407 config SECTION_MISMATCH_WARN_ONLY
408 bool "Make section mismatch errors non-fatal"
411 If you say N here, the build process will fail if there are any
412 section mismatch, instead of just throwing warnings.
416 config DEBUG_FORCE_FUNCTION_ALIGN_64B
417 bool "Force all function address 64B aligned" if EXPERT
419 There are cases that a commit from one domain changes the function
420 address alignment of other domains, and cause magic performance
421 bump (regression or improvement). Enable this option will help to
422 verify if the bump is caused by function alignment changes, while
423 it will slightly increase the kernel size and affect icache usage.
425 It is mainly for debug and performance tuning use.
428 # Select this config option from the architecture Kconfig, if it
429 # is preferred to always offer frame pointers as a config
430 # option on the architecture (regardless of KERNEL_DEBUG):
432 config ARCH_WANT_FRAME_POINTERS
436 bool "Compile the kernel with frame pointers"
437 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
438 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
440 If you say Y here the resulting kernel image will be slightly
441 larger and slower, but it gives very useful debugging information
442 in case of kernel bugs. (precise oopses/stacktraces/warnings)
444 config STACK_VALIDATION
445 bool "Compile-time stack metadata validation"
446 depends on HAVE_STACK_VALIDATION
449 Add compile-time checks to validate stack metadata, including frame
450 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
451 that runtime stack traces are more reliable.
453 This is also a prerequisite for generation of ORC unwind data, which
454 is needed for CONFIG_UNWINDER_ORC.
456 For more information, see
457 tools/objtool/Documentation/stack-validation.txt.
459 config VMLINUX_VALIDATION
461 depends on STACK_VALIDATION && DEBUG_ENTRY && !PARAVIRT
465 bool "Generate vmlinux.map file when linking"
468 Selecting this option will pass "-Map=vmlinux.map" to ld
469 when linking vmlinux. That file can be useful for verifying
470 and debugging magic section games, and for seeing which
471 pieces of code get eliminated with
472 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
474 config DEBUG_FORCE_WEAK_PER_CPU
475 bool "Force weak per-cpu definitions"
476 depends on DEBUG_KERNEL
478 s390 and alpha require percpu variables in modules to be
479 defined weak to work around addressing range issue which
480 puts the following two restrictions on percpu variable
483 1. percpu symbols must be unique whether static or not
484 2. percpu variables can't be defined inside a function
486 To ensure that generic code follows the above rules, this
487 option forces all percpu variables to be defined as weak.
489 endmenu # "Compiler options"
491 menu "Generic Kernel Debugging Instruments"
494 bool "Magic SysRq key"
497 If you say Y here, you will have some control over the system even
498 if the system crashes for example during kernel debugging (e.g., you
499 will be able to flush the buffer cache to disk, reboot the system
500 immediately or dump some status information). This is accomplished
501 by pressing various keys while holding SysRq (Alt+PrintScreen). It
502 also works on a serial console (on PC hardware at least), if you
503 send a BREAK and then within 5 seconds a command keypress. The
504 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
505 Don't say Y unless you really know what this hack does.
507 config MAGIC_SYSRQ_DEFAULT_ENABLE
508 hex "Enable magic SysRq key functions by default"
509 depends on MAGIC_SYSRQ
512 Specifies which SysRq key functions are enabled by default.
513 This may be set to 1 or 0 to enable or disable them all, or
514 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
516 config MAGIC_SYSRQ_SERIAL
517 bool "Enable magic SysRq key over serial"
518 depends on MAGIC_SYSRQ
521 Many embedded boards have a disconnected TTL level serial which can
522 generate some garbage that can lead to spurious false sysrq detects.
523 This option allows you to decide whether you want to enable the
526 config MAGIC_SYSRQ_SERIAL_SEQUENCE
527 string "Char sequence that enables magic SysRq over serial"
528 depends on MAGIC_SYSRQ_SERIAL
531 Specifies a sequence of characters that can follow BREAK to enable
532 SysRq on a serial console.
534 If unsure, leave an empty string and the option will not be enabled.
537 bool "Debug Filesystem"
539 debugfs is a virtual file system that kernel developers use to put
540 debugging files into. Enable this option to be able to read and
541 write to these files.
543 For detailed documentation on the debugfs API, see
544 Documentation/filesystems/.
549 prompt "Debugfs default access"
551 default DEBUG_FS_ALLOW_ALL
553 This selects the default access restrictions for debugfs.
554 It can be overridden with kernel command line option
555 debugfs=[on,no-mount,off]. The restrictions apply for API access
556 and filesystem registration.
558 config DEBUG_FS_ALLOW_ALL
561 No restrictions apply. Both API and filesystem registration
562 is on. This is the normal default operation.
564 config DEBUG_FS_DISALLOW_MOUNT
565 bool "Do not register debugfs as filesystem"
567 The API is open but filesystem is not loaded. Clients can still do
568 their work and read with debug tools that do not need
571 config DEBUG_FS_ALLOW_NONE
574 Access is off. Clients get -PERM when trying to create nodes in
575 debugfs tree and debugfs is not registered as a filesystem.
576 Client can then back-off or continue without debugfs access.
580 source "lib/Kconfig.kgdb"
581 source "lib/Kconfig.ubsan"
582 source "lib/Kconfig.kcsan"
587 bool "Kernel debugging"
589 Say Y here if you are developing drivers or trying to debug and
590 identify kernel problems.
593 bool "Miscellaneous debug code"
595 depends on DEBUG_KERNEL
597 Say Y here if you need to enable miscellaneous debug code that should
598 be under a more specific debug option but isn't.
601 menu "Memory Debugging"
603 source "mm/Kconfig.debug"
606 bool "Debug object operations"
607 depends on DEBUG_KERNEL
609 If you say Y here, additional code will be inserted into the
610 kernel to track the life time of various objects and validate
611 the operations on those objects.
613 config DEBUG_OBJECTS_SELFTEST
614 bool "Debug objects selftest"
615 depends on DEBUG_OBJECTS
617 This enables the selftest of the object debug code.
619 config DEBUG_OBJECTS_FREE
620 bool "Debug objects in freed memory"
621 depends on DEBUG_OBJECTS
623 This enables checks whether a k/v free operation frees an area
624 which contains an object which has not been deactivated
625 properly. This can make kmalloc/kfree-intensive workloads
628 config DEBUG_OBJECTS_TIMERS
629 bool "Debug timer objects"
630 depends on DEBUG_OBJECTS
632 If you say Y here, additional code will be inserted into the
633 timer routines to track the life time of timer objects and
634 validate the timer operations.
636 config DEBUG_OBJECTS_WORK
637 bool "Debug work objects"
638 depends on DEBUG_OBJECTS
640 If you say Y here, additional code will be inserted into the
641 work queue routines to track the life time of work objects and
642 validate the work operations.
644 config DEBUG_OBJECTS_RCU_HEAD
645 bool "Debug RCU callbacks objects"
646 depends on DEBUG_OBJECTS
648 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
650 config DEBUG_OBJECTS_PERCPU_COUNTER
651 bool "Debug percpu counter objects"
652 depends on DEBUG_OBJECTS
654 If you say Y here, additional code will be inserted into the
655 percpu counter routines to track the life time of percpu counter
656 objects and validate the percpu counter operations.
658 config DEBUG_OBJECTS_ENABLE_DEFAULT
659 int "debug_objects bootup default value (0-1)"
662 depends on DEBUG_OBJECTS
664 Debug objects boot parameter default value
667 bool "Debug slab memory allocations"
668 depends on DEBUG_KERNEL && SLAB
670 Say Y here to have the kernel do limited verification on memory
671 allocation as well as poisoning memory on free to catch use of freed
672 memory. This can make kmalloc/kfree-intensive workloads much slower.
675 bool "SLUB debugging on by default"
676 depends on SLUB && SLUB_DEBUG
679 Boot with debugging on by default. SLUB boots by default with
680 the runtime debug capabilities switched off. Enabling this is
681 equivalent to specifying the "slub_debug" parameter on boot.
682 There is no support for more fine grained debug control like
683 possible with slub_debug=xxx. SLUB debugging may be switched
684 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
689 bool "Enable SLUB performance statistics"
690 depends on SLUB && SYSFS
692 SLUB statistics are useful to debug SLUBs allocation behavior in
693 order find ways to optimize the allocator. This should never be
694 enabled for production use since keeping statistics slows down
695 the allocator by a few percentage points. The slabinfo command
696 supports the determination of the most active slabs to figure
697 out which slabs are relevant to a particular load.
698 Try running: slabinfo -DA
700 config HAVE_DEBUG_KMEMLEAK
703 config DEBUG_KMEMLEAK
704 bool "Kernel memory leak detector"
705 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
707 select STACKTRACE if STACKTRACE_SUPPORT
711 Say Y here if you want to enable the memory leak
712 detector. The memory allocation/freeing is traced in a way
713 similar to the Boehm's conservative garbage collector, the
714 difference being that the orphan objects are not freed but
715 only shown in /sys/kernel/debug/kmemleak. Enabling this
716 feature will introduce an overhead to memory
717 allocations. See Documentation/dev-tools/kmemleak.rst for more
720 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
721 of finding leaks due to the slab objects poisoning.
723 In order to access the kmemleak file, debugfs needs to be
724 mounted (usually at /sys/kernel/debug).
726 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
727 int "Kmemleak memory pool size"
728 depends on DEBUG_KMEMLEAK
732 Kmemleak must track all the memory allocations to avoid
733 reporting false positives. Since memory may be allocated or
734 freed before kmemleak is fully initialised, use a static pool
735 of metadata objects to track such callbacks. After kmemleak is
736 fully initialised, this memory pool acts as an emergency one
737 if slab allocations fail.
739 config DEBUG_KMEMLEAK_TEST
740 tristate "Simple test for the kernel memory leak detector"
741 depends on DEBUG_KMEMLEAK && m
743 This option enables a module that explicitly leaks memory.
747 config DEBUG_KMEMLEAK_DEFAULT_OFF
748 bool "Default kmemleak to off"
749 depends on DEBUG_KMEMLEAK
751 Say Y here to disable kmemleak by default. It can then be enabled
752 on the command line via kmemleak=on.
754 config DEBUG_KMEMLEAK_AUTO_SCAN
755 bool "Enable kmemleak auto scan thread on boot up"
757 depends on DEBUG_KMEMLEAK
759 Depending on the cpu, kmemleak scan may be cpu intensive and can
760 stall user tasks at times. This option enables/disables automatic
761 kmemleak scan at boot up.
763 Say N here to disable kmemleak auto scan thread to stop automatic
764 scanning. Disabling this option disables automatic reporting of
769 config DEBUG_STACK_USAGE
770 bool "Stack utilization instrumentation"
771 depends on DEBUG_KERNEL && !IA64
773 Enables the display of the minimum amount of free stack which each
774 task has ever had available in the sysrq-T and sysrq-P debug output.
776 This option will slow down process creation somewhat.
778 config SCHED_STACK_END_CHECK
779 bool "Detect stack corruption on calls to schedule()"
780 depends on DEBUG_KERNEL
783 This option checks for a stack overrun on calls to schedule().
784 If the stack end location is found to be over written always panic as
785 the content of the corrupted region can no longer be trusted.
786 This is to ensure no erroneous behaviour occurs which could result in
787 data corruption or a sporadic crash at a later stage once the region
788 is examined. The runtime overhead introduced is minimal.
790 config ARCH_HAS_DEBUG_VM_PGTABLE
793 An architecture should select this when it can successfully
794 build and run DEBUG_VM_PGTABLE.
798 depends on DEBUG_KERNEL
800 Enable this to turn on extended checks in the virtual-memory system
801 that may impact performance.
805 config DEBUG_VM_VMACACHE
806 bool "Debug VMA caching"
809 Enable this to turn on VMA caching debug information. Doing so
810 can cause significant overhead, so only enable it in non-production
816 bool "Debug VM red-black trees"
819 Enable VM red-black tree debugging information and extra validations.
823 config DEBUG_VM_PGFLAGS
824 bool "Debug page-flags operations"
827 Enables extra validation on page flags operations.
831 config DEBUG_VM_PGTABLE
832 bool "Debug arch page table for semantics compliance"
834 depends on ARCH_HAS_DEBUG_VM_PGTABLE
835 default y if DEBUG_VM
837 This option provides a debug method which can be used to test
838 architecture page table helper functions on various platforms in
839 verifying if they comply with expected generic MM semantics. This
840 will help architecture code in making sure that any changes or
841 new additions of these helpers still conform to expected
842 semantics of the generic MM. Platforms will have to opt in for
843 this through ARCH_HAS_DEBUG_VM_PGTABLE.
847 config ARCH_HAS_DEBUG_VIRTUAL
851 bool "Debug VM translations"
852 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
854 Enable some costly sanity checks in virtual to page code. This can
855 catch mistakes with virt_to_page() and friends.
859 config DEBUG_NOMMU_REGIONS
860 bool "Debug the global anon/private NOMMU mapping region tree"
861 depends on DEBUG_KERNEL && !MMU
863 This option causes the global tree of anonymous and private mapping
864 regions to be regularly checked for invalid topology.
866 config DEBUG_MEMORY_INIT
867 bool "Debug memory initialisation" if EXPERT
870 Enable this for additional checks during memory initialisation.
871 The sanity checks verify aspects of the VM such as the memory model
872 and other information provided by the architecture. Verbose
873 information will be printed at KERN_DEBUG loglevel depending
874 on the mminit_loglevel= command-line option.
878 config MEMORY_NOTIFIER_ERROR_INJECT
879 tristate "Memory hotplug notifier error injection module"
880 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
882 This option provides the ability to inject artificial errors to
883 memory hotplug notifier chain callbacks. It is controlled through
884 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
886 If the notifier call chain should be failed with some events
887 notified, write the error code to "actions/<notifier event>/error".
889 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
891 # cd /sys/kernel/debug/notifier-error-inject/memory
892 # echo -12 > actions/MEM_GOING_OFFLINE/error
893 # echo offline > /sys/devices/system/memory/memoryXXX/state
894 bash: echo: write error: Cannot allocate memory
896 To compile this code as a module, choose M here: the module will
897 be called memory-notifier-error-inject.
901 config DEBUG_PER_CPU_MAPS
902 bool "Debug access to per_cpu maps"
903 depends on DEBUG_KERNEL
906 Say Y to verify that the per_cpu map being accessed has
907 been set up. This adds a fair amount of code to kernel memory
908 and decreases performance.
912 config DEBUG_KMAP_LOCAL
913 bool "Debug kmap_local temporary mappings"
914 depends on DEBUG_KERNEL && KMAP_LOCAL
916 This option enables additional error checking for the kmap_local
917 infrastructure. Disable for production use.
919 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
922 config DEBUG_KMAP_LOCAL_FORCE_MAP
923 bool "Enforce kmap_local temporary mappings"
924 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
926 select DEBUG_KMAP_LOCAL
928 This option enforces temporary mappings through the kmap_local
929 mechanism for non-highmem pages and on non-highmem systems.
930 Disable this for production systems!
933 bool "Highmem debugging"
934 depends on DEBUG_KERNEL && HIGHMEM
935 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
936 select DEBUG_KMAP_LOCAL
938 This option enables additional error checking for high memory
939 systems. Disable for production systems.
941 config HAVE_DEBUG_STACKOVERFLOW
944 config DEBUG_STACKOVERFLOW
945 bool "Check for stack overflows"
946 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
948 Say Y here if you want to check for overflows of kernel, IRQ
949 and exception stacks (if your architecture uses them). This
950 option will show detailed messages if free stack space drops
951 below a certain limit.
953 These kinds of bugs usually occur when call-chains in the
954 kernel get too deep, especially when interrupts are
957 Use this in cases where you see apparently random memory
958 corruption, especially if it appears in 'struct thread_info'
960 If in doubt, say "N".
962 source "lib/Kconfig.kasan"
963 source "lib/Kconfig.kfence"
965 endmenu # "Memory Debugging"
968 bool "Debug shared IRQ handlers"
969 depends on DEBUG_KERNEL
971 Enable this to generate a spurious interrupt just before a shared
972 interrupt handler is deregistered (generating one when registering
973 is currently disabled). Drivers need to handle this correctly. Some
974 don't and need to be caught.
976 menu "Debug Oops, Lockups and Hangs"
981 Say Y here to enable the kernel to panic when it oopses. This
982 has the same effect as setting oops=panic on the kernel command
985 This feature is useful to ensure that the kernel does not do
986 anything erroneous after an oops which could result in data
987 corruption or other issues.
991 config PANIC_ON_OOPS_VALUE
994 default 0 if !PANIC_ON_OOPS
995 default 1 if PANIC_ON_OOPS
1001 Set the timeout value (in seconds) until a reboot occurs when
1002 the kernel panics. If n = 0, then we wait forever. A timeout
1003 value n > 0 will wait n seconds before rebooting, while a timeout
1004 value n < 0 will reboot immediately.
1006 config LOCKUP_DETECTOR
1009 config SOFTLOCKUP_DETECTOR
1010 bool "Detect Soft Lockups"
1011 depends on DEBUG_KERNEL && !S390
1012 select LOCKUP_DETECTOR
1014 Say Y here to enable the kernel to act as a watchdog to detect
1017 Softlockups are bugs that cause the kernel to loop in kernel
1018 mode for more than 20 seconds, without giving other tasks a
1019 chance to run. The current stack trace is displayed upon
1020 detection and the system will stay locked up.
1022 config BOOTPARAM_SOFTLOCKUP_PANIC
1023 bool "Panic (Reboot) On Soft Lockups"
1024 depends on SOFTLOCKUP_DETECTOR
1026 Say Y here to enable the kernel to panic on "soft lockups",
1027 which are bugs that cause the kernel to loop in kernel
1028 mode for more than 20 seconds (configurable using the watchdog_thresh
1029 sysctl), without giving other tasks a chance to run.
1031 The panic can be used in combination with panic_timeout,
1032 to cause the system to reboot automatically after a
1033 lockup has been detected. This feature is useful for
1034 high-availability systems that have uptime guarantees and
1035 where a lockup must be resolved ASAP.
1039 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
1041 depends on SOFTLOCKUP_DETECTOR
1043 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
1044 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
1046 config HARDLOCKUP_DETECTOR_PERF
1048 select SOFTLOCKUP_DETECTOR
1051 # Enables a timestamp based low pass filter to compensate for perf based
1052 # hard lockup detection which runs too fast due to turbo modes.
1054 config HARDLOCKUP_CHECK_TIMESTAMP
1058 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1059 # lockup detector rather than the perf based detector.
1061 config HARDLOCKUP_DETECTOR
1062 bool "Detect Hard Lockups"
1063 depends on DEBUG_KERNEL && !S390
1064 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1065 select LOCKUP_DETECTOR
1066 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1067 select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH
1069 Say Y here to enable the kernel to act as a watchdog to detect
1072 Hardlockups are bugs that cause the CPU to loop in kernel mode
1073 for more than 10 seconds, without letting other interrupts have a
1074 chance to run. The current stack trace is displayed upon detection
1075 and the system will stay locked up.
1077 config BOOTPARAM_HARDLOCKUP_PANIC
1078 bool "Panic (Reboot) On Hard Lockups"
1079 depends on HARDLOCKUP_DETECTOR
1081 Say Y here to enable the kernel to panic on "hard lockups",
1082 which are bugs that cause the kernel to loop in kernel
1083 mode with interrupts disabled for more than 10 seconds (configurable
1084 using the watchdog_thresh sysctl).
1088 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
1090 depends on HARDLOCKUP_DETECTOR
1092 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
1093 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
1095 config DETECT_HUNG_TASK
1096 bool "Detect Hung Tasks"
1097 depends on DEBUG_KERNEL
1098 default SOFTLOCKUP_DETECTOR
1100 Say Y here to enable the kernel to detect "hung tasks",
1101 which are bugs that cause the task to be stuck in
1102 uninterruptible "D" state indefinitely.
1104 When a hung task is detected, the kernel will print the
1105 current stack trace (which you should report), but the
1106 task will stay in uninterruptible state. If lockdep is
1107 enabled then all held locks will also be reported. This
1108 feature has negligible overhead.
1110 config DEFAULT_HUNG_TASK_TIMEOUT
1111 int "Default timeout for hung task detection (in seconds)"
1112 depends on DETECT_HUNG_TASK
1115 This option controls the default timeout (in seconds) used
1116 to determine when a task has become non-responsive and should
1119 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1120 sysctl or by writing a value to
1121 /proc/sys/kernel/hung_task_timeout_secs.
1123 A timeout of 0 disables the check. The default is two minutes.
1124 Keeping the default should be fine in most cases.
1126 config BOOTPARAM_HUNG_TASK_PANIC
1127 bool "Panic (Reboot) On Hung Tasks"
1128 depends on DETECT_HUNG_TASK
1130 Say Y here to enable the kernel to panic on "hung tasks",
1131 which are bugs that cause the kernel to leave a task stuck
1132 in uninterruptible "D" state.
1134 The panic can be used in combination with panic_timeout,
1135 to cause the system to reboot automatically after a
1136 hung task has been detected. This feature is useful for
1137 high-availability systems that have uptime guarantees and
1138 where a hung tasks must be resolved ASAP.
1142 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
1144 depends on DETECT_HUNG_TASK
1146 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
1147 default 1 if BOOTPARAM_HUNG_TASK_PANIC
1150 bool "Detect Workqueue Stalls"
1151 depends on DEBUG_KERNEL
1153 Say Y here to enable stall detection on workqueues. If a
1154 worker pool doesn't make forward progress on a pending work
1155 item for over a given amount of time, 30s by default, a
1156 warning message is printed along with dump of workqueue
1157 state. This can be configured through kernel parameter
1158 "workqueue.watchdog_thresh" and its sysfs counterpart.
1161 tristate "Test module to generate lockups"
1164 This builds the "test_lockup" module that helps to make sure
1165 that watchdogs and lockup detectors are working properly.
1167 Depending on module parameters it could emulate soft or hard
1168 lockup, "hung task", or locking arbitrary lock for a long time.
1169 Also it could generate series of lockups with cooling-down periods.
1173 endmenu # "Debug lockups and hangs"
1175 menu "Scheduler Debugging"
1178 bool "Collect scheduler debugging info"
1179 depends on DEBUG_KERNEL && PROC_FS
1182 If you say Y here, the /proc/sched_debug file will be provided
1183 that can help debug the scheduler. The runtime overhead of this
1191 bool "Collect scheduler statistics"
1192 depends on DEBUG_KERNEL && PROC_FS
1195 If you say Y here, additional code will be inserted into the
1196 scheduler and related routines to collect statistics about
1197 scheduler behavior and provide them in /proc/schedstat. These
1198 stats may be useful for both tuning and debugging the scheduler
1199 If you aren't debugging the scheduler or trying to tune a specific
1200 application, you can say N to avoid the very slight overhead
1205 config DEBUG_TIMEKEEPING
1206 bool "Enable extra timekeeping sanity checking"
1208 This option will enable additional timekeeping sanity checks
1209 which may be helpful when diagnosing issues where timekeeping
1210 problems are suspected.
1212 This may include checks in the timekeeping hotpaths, so this
1213 option may have a (very small) performance impact to some
1218 config DEBUG_PREEMPT
1219 bool "Debug preemptible kernel"
1220 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1223 If you say Y here then the kernel will use a debug variant of the
1224 commonly used smp_processor_id() function and will print warnings
1225 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1226 will detect preemption count underflows.
1228 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1230 config LOCK_DEBUGGING_SUPPORT
1232 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1235 config PROVE_LOCKING
1236 bool "Lock debugging: prove locking correctness"
1237 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1239 select DEBUG_SPINLOCK
1240 select DEBUG_MUTEXES if !PREEMPT_RT
1241 select DEBUG_RT_MUTEXES if RT_MUTEXES
1243 select DEBUG_WW_MUTEX_SLOWPATH
1244 select DEBUG_LOCK_ALLOC
1245 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1246 select TRACE_IRQFLAGS
1249 This feature enables the kernel to prove that all locking
1250 that occurs in the kernel runtime is mathematically
1251 correct: that under no circumstance could an arbitrary (and
1252 not yet triggered) combination of observed locking
1253 sequences (on an arbitrary number of CPUs, running an
1254 arbitrary number of tasks and interrupt contexts) cause a
1257 In short, this feature enables the kernel to report locking
1258 related deadlocks before they actually occur.
1260 The proof does not depend on how hard and complex a
1261 deadlock scenario would be to trigger: how many
1262 participant CPUs, tasks and irq-contexts would be needed
1263 for it to trigger. The proof also does not depend on
1264 timing: if a race and a resulting deadlock is possible
1265 theoretically (no matter how unlikely the race scenario
1266 is), it will be proven so and will immediately be
1267 reported by the kernel (once the event is observed that
1268 makes the deadlock theoretically possible).
1270 If a deadlock is impossible (i.e. the locking rules, as
1271 observed by the kernel, are mathematically correct), the
1272 kernel reports nothing.
1274 NOTE: this feature can also be enabled for rwlocks, mutexes
1275 and rwsems - in which case all dependencies between these
1276 different locking variants are observed and mapped too, and
1277 the proof of observed correctness is also maintained for an
1278 arbitrary combination of these separate locking variants.
1280 For more details, see Documentation/locking/lockdep-design.rst.
1282 config PROVE_RAW_LOCK_NESTING
1283 bool "Enable raw_spinlock - spinlock nesting checks"
1284 depends on PROVE_LOCKING
1287 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1288 that the lock nesting rules for PREEMPT_RT enabled kernels are
1291 NOTE: There are known nesting problems. So if you enable this
1292 option expect lockdep splats until these problems have been fully
1293 addressed which is work in progress. This config switch allows to
1294 identify and analyze these problems. It will be removed and the
1295 check permanently enabled once the main issues have been fixed.
1297 If unsure, select N.
1300 bool "Lock usage statistics"
1301 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1303 select DEBUG_SPINLOCK
1304 select DEBUG_MUTEXES if !PREEMPT_RT
1305 select DEBUG_RT_MUTEXES if RT_MUTEXES
1306 select DEBUG_LOCK_ALLOC
1309 This feature enables tracking lock contention points
1311 For more details, see Documentation/locking/lockstat.rst
1313 This also enables lock events required by "perf lock",
1315 If you want to use "perf lock", you also need to turn on
1316 CONFIG_EVENT_TRACING.
1318 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1319 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1321 config DEBUG_RT_MUTEXES
1322 bool "RT Mutex debugging, deadlock detection"
1323 depends on DEBUG_KERNEL && RT_MUTEXES
1325 This allows rt mutex semantics violations and rt mutex related
1326 deadlocks (lockups) to be detected and reported automatically.
1328 config DEBUG_SPINLOCK
1329 bool "Spinlock and rw-lock debugging: basic checks"
1330 depends on DEBUG_KERNEL
1331 select UNINLINE_SPIN_UNLOCK
1333 Say Y here and build SMP to catch missing spinlock initialization
1334 and certain other kinds of spinlock errors commonly made. This is
1335 best used in conjunction with the NMI watchdog so that spinlock
1336 deadlocks are also debuggable.
1338 config DEBUG_MUTEXES
1339 bool "Mutex debugging: basic checks"
1340 depends on DEBUG_KERNEL && !PREEMPT_RT
1342 This feature allows mutex semantics violations to be detected and
1345 config DEBUG_WW_MUTEX_SLOWPATH
1346 bool "Wait/wound mutex debugging: Slowpath testing"
1347 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1348 select DEBUG_LOCK_ALLOC
1349 select DEBUG_SPINLOCK
1350 select DEBUG_MUTEXES if !PREEMPT_RT
1351 select DEBUG_RT_MUTEXES if PREEMPT_RT
1353 This feature enables slowpath testing for w/w mutex users by
1354 injecting additional -EDEADLK wound/backoff cases. Together with
1355 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1356 will test all possible w/w mutex interface abuse with the
1357 exception of simply not acquiring all the required locks.
1358 Note that this feature can introduce significant overhead, so
1359 it really should not be enabled in a production or distro kernel,
1360 even a debug kernel. If you are a driver writer, enable it. If
1361 you are a distro, do not.
1364 bool "RW Semaphore debugging: basic checks"
1365 depends on DEBUG_KERNEL
1367 This debugging feature allows mismatched rw semaphore locks
1368 and unlocks to be detected and reported.
1370 config DEBUG_LOCK_ALLOC
1371 bool "Lock debugging: detect incorrect freeing of live locks"
1372 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1373 select DEBUG_SPINLOCK
1374 select DEBUG_MUTEXES if !PREEMPT_RT
1375 select DEBUG_RT_MUTEXES if RT_MUTEXES
1378 This feature will check whether any held lock (spinlock, rwlock,
1379 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1380 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1381 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1382 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1383 held during task exit.
1387 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1392 config LOCKDEP_SMALL
1396 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1397 depends on LOCKDEP && !LOCKDEP_SMALL
1401 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1403 config LOCKDEP_CHAINS_BITS
1404 int "Bitsize for MAX_LOCKDEP_CHAINS"
1405 depends on LOCKDEP && !LOCKDEP_SMALL
1409 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1411 config LOCKDEP_STACK_TRACE_BITS
1412 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1413 depends on LOCKDEP && !LOCKDEP_SMALL
1417 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1419 config LOCKDEP_STACK_TRACE_HASH_BITS
1420 int "Bitsize for STACK_TRACE_HASH_SIZE"
1421 depends on LOCKDEP && !LOCKDEP_SMALL
1425 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1427 config LOCKDEP_CIRCULAR_QUEUE_BITS
1428 int "Bitsize for elements in circular_queue struct"
1433 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1435 config DEBUG_LOCKDEP
1436 bool "Lock dependency engine debugging"
1437 depends on DEBUG_KERNEL && LOCKDEP
1438 select DEBUG_IRQFLAGS
1440 If you say Y here, the lock dependency engine will do
1441 additional runtime checks to debug itself, at the price
1442 of more runtime overhead.
1444 config DEBUG_ATOMIC_SLEEP
1445 bool "Sleep inside atomic section checking"
1446 select PREEMPT_COUNT
1447 depends on DEBUG_KERNEL
1448 depends on !ARCH_NO_PREEMPT
1450 If you say Y here, various routines which may sleep will become very
1451 noisy if they are called inside atomic sections: when a spinlock is
1452 held, inside an rcu read side critical section, inside preempt disabled
1453 sections, inside an interrupt, etc...
1455 config DEBUG_LOCKING_API_SELFTESTS
1456 bool "Locking API boot-time self-tests"
1457 depends on DEBUG_KERNEL
1459 Say Y here if you want the kernel to run a short self-test during
1460 bootup. The self-test checks whether common types of locking bugs
1461 are detected by debugging mechanisms or not. (if you disable
1462 lock debugging then those bugs won't be detected of course.)
1463 The following locking APIs are covered: spinlocks, rwlocks,
1466 config LOCK_TORTURE_TEST
1467 tristate "torture tests for locking"
1468 depends on DEBUG_KERNEL
1471 This option provides a kernel module that runs torture tests
1472 on kernel locking primitives. The kernel module may be built
1473 after the fact on the running kernel to be tested, if desired.
1475 Say Y here if you want kernel locking-primitive torture tests
1476 to be built into the kernel.
1477 Say M if you want these torture tests to build as a module.
1478 Say N if you are unsure.
1480 config WW_MUTEX_SELFTEST
1481 tristate "Wait/wound mutex selftests"
1483 This option provides a kernel module that runs tests on the
1484 on the struct ww_mutex locking API.
1486 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1487 with this test harness.
1489 Say M if you want these self tests to build as a module.
1490 Say N if you are unsure.
1492 config SCF_TORTURE_TEST
1493 tristate "torture tests for smp_call_function*()"
1494 depends on DEBUG_KERNEL
1497 This option provides a kernel module that runs torture tests
1498 on the smp_call_function() family of primitives. The kernel
1499 module may be built after the fact on the running kernel to
1500 be tested, if desired.
1502 config CSD_LOCK_WAIT_DEBUG
1503 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1504 depends on DEBUG_KERNEL
1508 This option enables debug prints when CPUs are slow to respond
1509 to the smp_call_function*() IPI wrappers. These debug prints
1510 include the IPI handler function currently executing (if any)
1511 and relevant stack traces.
1513 endmenu # lock debugging
1515 config TRACE_IRQFLAGS
1516 depends on TRACE_IRQFLAGS_SUPPORT
1519 Enables hooks to interrupt enabling and disabling for
1520 either tracing or lock debugging.
1522 config TRACE_IRQFLAGS_NMI
1524 depends on TRACE_IRQFLAGS
1525 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1527 config DEBUG_IRQFLAGS
1528 bool "Debug IRQ flag manipulation"
1530 Enables checks for potentially unsafe enabling or disabling of
1531 interrupts, such as calling raw_local_irq_restore() when interrupts
1535 bool "Stack backtrace support"
1536 depends on STACKTRACE_SUPPORT
1538 This option causes the kernel to create a /proc/pid/stack for
1539 every process, showing its current stack trace.
1540 It is also used by various kernel debugging features that require
1541 stack trace generation.
1543 config WARN_ALL_UNSEEDED_RANDOM
1544 bool "Warn for all uses of unseeded randomness"
1547 Some parts of the kernel contain bugs relating to their use of
1548 cryptographically secure random numbers before it's actually possible
1549 to generate those numbers securely. This setting ensures that these
1550 flaws don't go unnoticed, by enabling a message, should this ever
1551 occur. This will allow people with obscure setups to know when things
1552 are going wrong, so that they might contact developers about fixing
1555 Unfortunately, on some models of some architectures getting
1556 a fully seeded CRNG is extremely difficult, and so this can
1557 result in dmesg getting spammed for a surprisingly long
1558 time. This is really bad from a security perspective, and
1559 so architecture maintainers really need to do what they can
1560 to get the CRNG seeded sooner after the system is booted.
1561 However, since users cannot do anything actionable to
1562 address this, by default the kernel will issue only a single
1563 warning for the first use of unseeded randomness.
1565 Say Y here if you want to receive warnings for all uses of
1566 unseeded randomness. This will be of use primarily for
1567 those developers interested in improving the security of
1568 Linux kernels running on their architecture (or
1571 config DEBUG_KOBJECT
1572 bool "kobject debugging"
1573 depends on DEBUG_KERNEL
1575 If you say Y here, some extra kobject debugging messages will be sent
1578 config DEBUG_KOBJECT_RELEASE
1579 bool "kobject release debugging"
1580 depends on DEBUG_OBJECTS_TIMERS
1582 kobjects are reference counted objects. This means that their
1583 last reference count put is not predictable, and the kobject can
1584 live on past the point at which a driver decides to drop it's
1585 initial reference to the kobject gained on allocation. An
1586 example of this would be a struct device which has just been
1589 However, some buggy drivers assume that after such an operation,
1590 the memory backing the kobject can be immediately freed. This
1591 goes completely against the principles of a refcounted object.
1593 If you say Y here, the kernel will delay the release of kobjects
1594 on the last reference count to improve the visibility of this
1595 kind of kobject release bug.
1597 config HAVE_DEBUG_BUGVERBOSE
1600 menu "Debug kernel data structures"
1603 bool "Debug linked list manipulation"
1604 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1606 Enable this to turn on extended checks in the linked-list
1612 bool "Debug priority linked list manipulation"
1613 depends on DEBUG_KERNEL
1615 Enable this to turn on extended checks in the priority-ordered
1616 linked-list (plist) walking routines. This checks the entire
1617 list multiple times during each manipulation.
1622 bool "Debug SG table operations"
1623 depends on DEBUG_KERNEL
1625 Enable this to turn on checks on scatter-gather tables. This can
1626 help find problems with drivers that do not properly initialize
1631 config DEBUG_NOTIFIERS
1632 bool "Debug notifier call chains"
1633 depends on DEBUG_KERNEL
1635 Enable this to turn on sanity checking for notifier call chains.
1636 This is most useful for kernel developers to make sure that
1637 modules properly unregister themselves from notifier chains.
1638 This is a relatively cheap check but if you care about maximum
1641 config BUG_ON_DATA_CORRUPTION
1642 bool "Trigger a BUG when data corruption is detected"
1645 Select this option if the kernel should BUG when it encounters
1646 data corruption in kernel memory structures when they get checked
1653 config DEBUG_CREDENTIALS
1654 bool "Debug credential management"
1655 depends on DEBUG_KERNEL
1657 Enable this to turn on some debug checking for credential
1658 management. The additional code keeps track of the number of
1659 pointers from task_structs to any given cred struct, and checks to
1660 see that this number never exceeds the usage count of the cred
1663 Furthermore, if SELinux is enabled, this also checks that the
1664 security pointer in the cred struct is never seen to be invalid.
1668 source "kernel/rcu/Kconfig.debug"
1670 config DEBUG_WQ_FORCE_RR_CPU
1671 bool "Force round-robin CPU selection for unbound work items"
1672 depends on DEBUG_KERNEL
1675 Workqueue used to implicitly guarantee that work items queued
1676 without explicit CPU specified are put on the local CPU. This
1677 guarantee is no longer true and while local CPU is still
1678 preferred work items may be put on foreign CPUs. Kernel
1679 parameter "workqueue.debug_force_rr_cpu" is added to force
1680 round-robin CPU selection to flush out usages which depend on the
1681 now broken guarantee. This config option enables the debug
1682 feature by default. When enabled, memory and cache locality will
1685 config CPU_HOTPLUG_STATE_CONTROL
1686 bool "Enable CPU hotplug state control"
1687 depends on DEBUG_KERNEL
1688 depends on HOTPLUG_CPU
1691 Allows to write steps between "offline" and "online" to the CPUs
1692 sysfs target file so states can be stepped granular. This is a debug
1693 option for now as the hotplug machinery cannot be stopped and
1694 restarted at arbitrary points yet.
1696 Say N if your are unsure.
1699 bool "Latency measuring infrastructure"
1700 depends on DEBUG_KERNEL
1701 depends on STACKTRACE_SUPPORT
1703 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1709 Enable this option if you want to use the LatencyTOP tool
1710 to find out which userspace is blocking on what kernel operations.
1712 source "kernel/trace/Kconfig"
1714 config PROVIDE_OHCI1394_DMA_INIT
1715 bool "Remote debugging over FireWire early on boot"
1716 depends on PCI && X86
1718 If you want to debug problems which hang or crash the kernel early
1719 on boot and the crashing machine has a FireWire port, you can use
1720 this feature to remotely access the memory of the crashed machine
1721 over FireWire. This employs remote DMA as part of the OHCI1394
1722 specification which is now the standard for FireWire controllers.
1724 With remote DMA, you can monitor the printk buffer remotely using
1725 firescope and access all memory below 4GB using fireproxy from gdb.
1726 Even controlling a kernel debugger is possible using remote DMA.
1730 If ohci1394_dma=early is used as boot parameter, it will initialize
1731 all OHCI1394 controllers which are found in the PCI config space.
1733 As all changes to the FireWire bus such as enabling and disabling
1734 devices cause a bus reset and thereby disable remote DMA for all
1735 devices, be sure to have the cable plugged and FireWire enabled on
1736 the debugging host before booting the debug target for debugging.
1738 This code (~1k) is freed after boot. By then, the firewire stack
1739 in charge of the OHCI-1394 controllers should be used instead.
1741 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1743 source "samples/Kconfig"
1745 config ARCH_HAS_DEVMEM_IS_ALLOWED
1748 config STRICT_DEVMEM
1749 bool "Filter access to /dev/mem"
1750 depends on MMU && DEVMEM
1751 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1752 default y if PPC || X86 || ARM64
1754 If this option is disabled, you allow userspace (root) access to all
1755 of memory, including kernel and userspace memory. Accidental
1756 access to this is obviously disastrous, but specific access can
1757 be used by people debugging the kernel. Note that with PAT support
1758 enabled, even in this case there are restrictions on /dev/mem
1759 use due to the cache aliasing requirements.
1761 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1762 file only allows userspace access to PCI space and the BIOS code and
1763 data regions. This is sufficient for dosemu and X and all common
1768 config IO_STRICT_DEVMEM
1769 bool "Filter I/O access to /dev/mem"
1770 depends on STRICT_DEVMEM
1772 If this option is disabled, you allow userspace (root) access to all
1773 io-memory regardless of whether a driver is actively using that
1774 range. Accidental access to this is obviously disastrous, but
1775 specific access can be used by people debugging kernel drivers.
1777 If this option is switched on, the /dev/mem file only allows
1778 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1779 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1780 if the driver using a given range cannot be disabled.
1784 menu "$(SRCARCH) Debugging"
1786 source "arch/$(SRCARCH)/Kconfig.debug"
1790 menu "Kernel Testing and Coverage"
1792 source "lib/kunit/Kconfig"
1794 config NOTIFIER_ERROR_INJECTION
1795 tristate "Notifier error injection"
1796 depends on DEBUG_KERNEL
1799 This option provides the ability to inject artificial errors to
1800 specified notifier chain callbacks. It is useful to test the error
1801 handling of notifier call chain failures.
1805 config PM_NOTIFIER_ERROR_INJECT
1806 tristate "PM notifier error injection module"
1807 depends on PM && NOTIFIER_ERROR_INJECTION
1808 default m if PM_DEBUG
1810 This option provides the ability to inject artificial errors to
1811 PM notifier chain callbacks. It is controlled through debugfs
1812 interface /sys/kernel/debug/notifier-error-inject/pm
1814 If the notifier call chain should be failed with some events
1815 notified, write the error code to "actions/<notifier event>/error".
1817 Example: Inject PM suspend error (-12 = -ENOMEM)
1819 # cd /sys/kernel/debug/notifier-error-inject/pm/
1820 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1821 # echo mem > /sys/power/state
1822 bash: echo: write error: Cannot allocate memory
1824 To compile this code as a module, choose M here: the module will
1825 be called pm-notifier-error-inject.
1829 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1830 tristate "OF reconfig notifier error injection module"
1831 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1833 This option provides the ability to inject artificial errors to
1834 OF reconfig notifier chain callbacks. It is controlled
1835 through debugfs interface under
1836 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1838 If the notifier call chain should be failed with some events
1839 notified, write the error code to "actions/<notifier event>/error".
1841 To compile this code as a module, choose M here: the module will
1842 be called of-reconfig-notifier-error-inject.
1846 config NETDEV_NOTIFIER_ERROR_INJECT
1847 tristate "Netdev notifier error injection module"
1848 depends on NET && NOTIFIER_ERROR_INJECTION
1850 This option provides the ability to inject artificial errors to
1851 netdevice notifier chain callbacks. It is controlled through debugfs
1852 interface /sys/kernel/debug/notifier-error-inject/netdev
1854 If the notifier call chain should be failed with some events
1855 notified, write the error code to "actions/<notifier event>/error".
1857 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1859 # cd /sys/kernel/debug/notifier-error-inject/netdev
1860 # echo -22 > actions/NETDEV_CHANGEMTU/error
1861 # ip link set eth0 mtu 1024
1862 RTNETLINK answers: Invalid argument
1864 To compile this code as a module, choose M here: the module will
1865 be called netdev-notifier-error-inject.
1869 config FUNCTION_ERROR_INJECTION
1871 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1873 config FAULT_INJECTION
1874 bool "Fault-injection framework"
1875 depends on DEBUG_KERNEL
1877 Provide fault-injection framework.
1878 For more details, see Documentation/fault-injection/.
1881 bool "Fault-injection capability for kmalloc"
1882 depends on FAULT_INJECTION
1883 depends on SLAB || SLUB
1885 Provide fault-injection capability for kmalloc.
1887 config FAIL_PAGE_ALLOC
1888 bool "Fault-injection capability for alloc_pages()"
1889 depends on FAULT_INJECTION
1891 Provide fault-injection capability for alloc_pages().
1893 config FAULT_INJECTION_USERCOPY
1894 bool "Fault injection capability for usercopy functions"
1895 depends on FAULT_INJECTION
1897 Provides fault-injection capability to inject failures
1898 in usercopy functions (copy_from_user(), get_user(), ...).
1900 config FAIL_MAKE_REQUEST
1901 bool "Fault-injection capability for disk IO"
1902 depends on FAULT_INJECTION && BLOCK
1904 Provide fault-injection capability for disk IO.
1906 config FAIL_IO_TIMEOUT
1907 bool "Fault-injection capability for faking disk interrupts"
1908 depends on FAULT_INJECTION && BLOCK
1910 Provide fault-injection capability on end IO handling. This
1911 will make the block layer "forget" an interrupt as configured,
1912 thus exercising the error handling.
1914 Only works with drivers that use the generic timeout handling,
1915 for others it won't do anything.
1918 bool "Fault-injection capability for futexes"
1920 depends on FAULT_INJECTION && FUTEX
1922 Provide fault-injection capability for futexes.
1924 config FAULT_INJECTION_DEBUG_FS
1925 bool "Debugfs entries for fault-injection capabilities"
1926 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1928 Enable configuration of fault-injection capabilities via debugfs.
1930 config FAIL_FUNCTION
1931 bool "Fault-injection capability for functions"
1932 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1934 Provide function-based fault-injection capability.
1935 This will allow you to override a specific function with a return
1936 with given return value. As a result, function caller will see
1937 an error value and have to handle it. This is useful to test the
1938 error handling in various subsystems.
1940 config FAIL_MMC_REQUEST
1941 bool "Fault-injection capability for MMC IO"
1942 depends on FAULT_INJECTION_DEBUG_FS && MMC
1944 Provide fault-injection capability for MMC IO.
1945 This will make the mmc core return data errors. This is
1946 useful to test the error handling in the mmc block device
1947 and to test how the mmc host driver handles retries from
1951 bool "Fault-injection capability for SunRPC"
1952 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1954 Provide fault-injection capability for SunRPC and
1957 config FAULT_INJECTION_STACKTRACE_FILTER
1958 bool "stacktrace filter for fault-injection capabilities"
1959 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1962 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1964 Provide stacktrace filter for fault-injection capabilities
1966 config ARCH_HAS_KCOV
1969 An architecture should select this when it can successfully
1970 build and run with CONFIG_KCOV. This typically requires
1971 disabling instrumentation for some early boot code.
1973 config CC_HAS_SANCOV_TRACE_PC
1974 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1978 bool "Code coverage for fuzzing"
1979 depends on ARCH_HAS_KCOV
1980 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1982 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1984 KCOV exposes kernel code coverage information in a form suitable
1985 for coverage-guided fuzzing (randomized testing).
1987 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1988 different machines and across reboots. If you need stable PC values,
1989 disable RANDOMIZE_BASE.
1991 For more details, see Documentation/dev-tools/kcov.rst.
1993 config KCOV_ENABLE_COMPARISONS
1994 bool "Enable comparison operands collection by KCOV"
1996 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
1998 KCOV also exposes operands of every comparison in the instrumented
1999 code along with operand sizes and PCs of the comparison instructions.
2000 These operands can be used by fuzzing engines to improve the quality
2001 of fuzzing coverage.
2003 config KCOV_INSTRUMENT_ALL
2004 bool "Instrument all code by default"
2008 If you are doing generic system call fuzzing (like e.g. syzkaller),
2009 then you will want to instrument the whole kernel and you should
2010 say y here. If you are doing more targeted fuzzing (like e.g.
2011 filesystem fuzzing with AFL) then you will want to enable coverage
2012 for more specific subsets of files, and should say n here.
2014 config KCOV_IRQ_AREA_SIZE
2015 hex "Size of interrupt coverage collection area in words"
2019 KCOV uses preallocated per-cpu areas to collect coverage from
2020 soft interrupts. This specifies the size of those areas in the
2021 number of unsigned long words.
2023 menuconfig RUNTIME_TESTING_MENU
2024 bool "Runtime Testing"
2027 if RUNTIME_TESTING_MENU
2030 tristate "Linux Kernel Dump Test Tool Module"
2033 This module enables testing of the different dumping mechanisms by
2034 inducing system failures at predefined crash points.
2035 If you don't need it: say N
2036 Choose M here to compile this code as a module. The module will be
2039 Documentation on how to use the module can be found in
2040 Documentation/fault-injection/provoke-crashes.rst
2042 config TEST_LIST_SORT
2043 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2045 default KUNIT_ALL_TESTS
2047 Enable this to turn on 'list_sort()' function test. This test is
2048 executed only once during system boot (so affects only boot time),
2049 or at module load time.
2053 config TEST_MIN_HEAP
2054 tristate "Min heap test"
2055 depends on DEBUG_KERNEL || m
2057 Enable this to turn on min heap function tests. This test is
2058 executed only once during system boot (so affects only boot time),
2059 or at module load time.
2064 tristate "Array-based sort test"
2065 depends on DEBUG_KERNEL || m
2067 This option enables the self-test function of 'sort()' at boot,
2068 or at module load time.
2073 tristate "64bit/32bit division and modulo test"
2074 depends on DEBUG_KERNEL || m
2076 Enable this to turn on 'do_div()' function test. This test is
2077 executed only once during system boot (so affects only boot time),
2078 or at module load time.
2082 config KPROBES_SANITY_TEST
2083 bool "Kprobes sanity tests"
2084 depends on DEBUG_KERNEL
2087 This option provides for testing basic kprobes functionality on
2088 boot. Samples of kprobe and kretprobe are inserted and
2089 verified for functionality.
2091 Say N if you are unsure.
2093 config BACKTRACE_SELF_TEST
2094 tristate "Self test for the backtrace code"
2095 depends on DEBUG_KERNEL
2097 This option provides a kernel module that can be used to test
2098 the kernel stack backtrace code. This option is not useful
2099 for distributions or general kernels, but only for kernel
2100 developers working on architecture code.
2102 Note that if you want to also test saved backtraces, you will
2103 have to enable STACKTRACE as well.
2105 Say N if you are unsure.
2108 tristate "Red-Black tree test"
2109 depends on DEBUG_KERNEL
2111 A benchmark measuring the performance of the rbtree library.
2112 Also includes rbtree invariant checks.
2114 config REED_SOLOMON_TEST
2115 tristate "Reed-Solomon library test"
2116 depends on DEBUG_KERNEL || m
2118 select REED_SOLOMON_ENC16
2119 select REED_SOLOMON_DEC16
2121 This option enables the self-test function of rslib at boot,
2122 or at module load time.
2126 config INTERVAL_TREE_TEST
2127 tristate "Interval tree test"
2128 depends on DEBUG_KERNEL
2129 select INTERVAL_TREE
2131 A benchmark measuring the performance of the interval tree library
2134 tristate "Per cpu operations test"
2135 depends on m && DEBUG_KERNEL
2137 Enable this option to build test module which validates per-cpu
2142 config ATOMIC64_SELFTEST
2143 tristate "Perform an atomic64_t self-test"
2145 Enable this option to test the atomic64_t functions at boot or
2146 at module load time.
2150 config ASYNC_RAID6_TEST
2151 tristate "Self test for hardware accelerated raid6 recovery"
2152 depends on ASYNC_RAID6_RECOV
2155 This is a one-shot self test that permutes through the
2156 recovery of all the possible two disk failure scenarios for a
2157 N-disk array. Recovery is performed with the asynchronous
2158 raid6 recovery routines, and will optionally use an offload
2159 engine if one is available.
2164 tristate "Test functions located in the hexdump module at runtime"
2166 config STRING_SELFTEST
2167 tristate "Test string functions at runtime"
2169 config TEST_STRING_HELPERS
2170 tristate "Test functions located in the string_helpers module at runtime"
2173 tristate "Test strscpy*() family of functions at runtime"
2176 tristate "Test kstrto*() family of functions at runtime"
2179 tristate "Test printf() family of functions at runtime"
2182 tristate "Test scanf() family of functions at runtime"
2185 tristate "Test bitmap_*() family of functions at runtime"
2187 Enable this option to test the bitmap functions at boot.
2192 tristate "Test functions located in the uuid module at runtime"
2195 tristate "Test the XArray code at runtime"
2197 config TEST_OVERFLOW
2198 tristate "Test check_*_overflow() functions at runtime"
2200 config TEST_RHASHTABLE
2201 tristate "Perform selftest on resizable hash table"
2203 Enable this option to test the rhashtable functions at boot.
2208 tristate "Perform selftest on hash functions"
2210 Enable this option to test the kernel's integer (<linux/hash.h>),
2211 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
2212 hash functions on boot (or module load).
2214 This is intended to help people writing architecture-specific
2215 optimized versions. If unsure, say N.
2218 tristate "Perform selftest on IDA functions"
2221 tristate "Perform selftest on priority array manager"
2224 Enable this option to test priority array manager on boot
2229 config TEST_IRQ_TIMINGS
2230 bool "IRQ timings selftest"
2231 depends on IRQ_TIMINGS
2233 Enable this option to test the irq timings code on boot.
2238 tristate "Test module loading with 'hello world' module"
2241 This builds the "test_module" module that emits "Hello, world"
2242 on printk when loaded. It is designed to be used for basic
2243 evaluation of the module loading subsystem (for example when
2244 validating module verification). It lacks any extra dependencies,
2245 and will not normally be loaded by the system unless explicitly
2251 tristate "Test module for compilation of bitops operations"
2254 This builds the "test_bitops" module that is much like the
2255 TEST_LKM module except that it does a basic exercise of the
2256 set/clear_bit macros and get_count_order/long to make sure there are
2257 no compiler warnings from C=1 sparse checker or -Wextra
2258 compilations. It has no dependencies and doesn't run or load unless
2259 explicitly requested by name. for example: modprobe test_bitops.
2264 tristate "Test module for stress/performance analysis of vmalloc allocator"
2269 This builds the "test_vmalloc" module that should be used for
2270 stress and performance analysis. So, any new change for vmalloc
2271 subsystem can be evaluated from performance and stability point
2276 config TEST_USER_COPY
2277 tristate "Test user/kernel boundary protections"
2280 This builds the "test_user_copy" module that runs sanity checks
2281 on the copy_to/from_user infrastructure, making sure basic
2282 user/kernel boundary testing is working. If it fails to load,
2283 a regression has been detected in the user/kernel memory boundary
2289 tristate "Test BPF filter functionality"
2292 This builds the "test_bpf" module that runs various test vectors
2293 against the BPF interpreter or BPF JIT compiler depending on the
2294 current setting. This is in particular useful for BPF JIT compiler
2295 development, but also to run regression tests against changes in
2296 the interpreter code. It also enables test stubs for eBPF maps and
2297 verifier used by user space verifier testsuite.
2301 config TEST_BLACKHOLE_DEV
2302 tristate "Test blackhole netdev functionality"
2305 This builds the "test_blackhole_dev" module that validates the
2306 data path through this blackhole netdev.
2310 config FIND_BIT_BENCHMARK
2311 tristate "Test find_bit functions"
2313 This builds the "test_find_bit" module that measure find_*_bit()
2314 functions performance.
2318 config TEST_FIRMWARE
2319 tristate "Test firmware loading via userspace interface"
2320 depends on FW_LOADER
2322 This builds the "test_firmware" module that creates a userspace
2323 interface for testing firmware loading. This can be used to
2324 control the triggering of firmware loading without needing an
2325 actual firmware-using device. The contents can be rechecked by
2331 tristate "sysctl test driver"
2332 depends on PROC_SYSCTL
2334 This builds the "test_sysctl" module. This driver enables to test the
2335 proc sysctl interfaces available to drivers safely without affecting
2336 production knobs which might alter system functionality.
2340 config BITFIELD_KUNIT
2341 tristate "KUnit test bitfield functions at runtime"
2344 Enable this option to test the bitfield functions at boot.
2346 KUnit tests run during boot and output the results to the debug log
2347 in TAP format (http://testanything.org/). Only useful for kernel devs
2348 running the KUnit test harness, and not intended for inclusion into a
2351 For more information on KUnit and unit tests in general please refer
2352 to the KUnit documentation in Documentation/dev-tools/kunit/.
2356 config RESOURCE_KUNIT_TEST
2357 tristate "KUnit test for resource API"
2360 This builds the resource API unit test.
2361 Tests the logic of API provided by resource.c and ioport.h.
2362 For more information on KUnit and unit tests in general please refer
2363 to the KUnit documentation in Documentation/dev-tools/kunit/.
2367 config SYSCTL_KUNIT_TEST
2368 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2370 default KUNIT_ALL_TESTS
2372 This builds the proc sysctl unit test, which runs on boot.
2373 Tests the API contract and implementation correctness of sysctl.
2374 For more information on KUnit and unit tests in general please refer
2375 to the KUnit documentation in Documentation/dev-tools/kunit/.
2379 config LIST_KUNIT_TEST
2380 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2382 default KUNIT_ALL_TESTS
2384 This builds the linked list KUnit test suite.
2385 It tests that the API and basic functionality of the list_head type
2386 and associated macros.
2388 KUnit tests run during boot and output the results to the debug log
2389 in TAP format (https://testanything.org/). Only useful for kernel devs
2390 running the KUnit test harness, and not intended for inclusion into a
2393 For more information on KUnit and unit tests in general please refer
2394 to the KUnit documentation in Documentation/dev-tools/kunit/.
2398 config LINEAR_RANGES_TEST
2399 tristate "KUnit test for linear_ranges"
2401 select LINEAR_RANGES
2403 This builds the linear_ranges unit test, which runs on boot.
2404 Tests the linear_ranges logic correctness.
2405 For more information on KUnit and unit tests in general please refer
2406 to the KUnit documentation in Documentation/dev-tools/kunit/.
2410 config CMDLINE_KUNIT_TEST
2411 tristate "KUnit test for cmdline API"
2414 This builds the cmdline API unit test.
2415 Tests the logic of API provided by cmdline.c.
2416 For more information on KUnit and unit tests in general please refer
2417 to the KUnit documentation in Documentation/dev-tools/kunit/.
2422 tristate "KUnit test for bits.h"
2425 This builds the bits unit test.
2426 Tests the logic of macros defined in bits.h.
2427 For more information on KUnit and unit tests in general please refer
2428 to the KUnit documentation in Documentation/dev-tools/kunit/.
2432 config SLUB_KUNIT_TEST
2433 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2434 depends on SLUB_DEBUG && KUNIT
2435 default KUNIT_ALL_TESTS
2437 This builds SLUB allocator unit test.
2438 Tests SLUB cache debugging functionality.
2439 For more information on KUnit and unit tests in general please refer
2440 to the KUnit documentation in Documentation/dev-tools/kunit/.
2444 config RATIONAL_KUNIT_TEST
2445 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2448 default KUNIT_ALL_TESTS
2450 This builds the rational math unit test.
2451 For more information on KUnit and unit tests in general please refer
2452 to the KUnit documentation in Documentation/dev-tools/kunit/.
2457 tristate "udelay test driver"
2459 This builds the "udelay_test" module that helps to make sure
2460 that udelay() is working properly.
2464 config TEST_STATIC_KEYS
2465 tristate "Test static keys"
2468 Test the static key interfaces.
2473 tristate "kmod stress tester"
2475 depends on NETDEVICES && NET_CORE && INET # for TUN
2482 Test the kernel's module loading mechanism: kmod. kmod implements
2483 support to load modules using the Linux kernel's usermode helper.
2484 This test provides a series of tests against kmod.
2486 Although technically you can either build test_kmod as a module or
2487 into the kernel we disallow building it into the kernel since
2488 it stress tests request_module() and this will very likely cause
2489 some issues by taking over precious threads available from other
2490 module load requests, ultimately this could be fatal.
2494 tools/testing/selftests/kmod/kmod.sh --help
2498 config TEST_DEBUG_VIRTUAL
2499 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2500 depends on DEBUG_VIRTUAL
2502 Test the kernel's ability to detect incorrect calls to
2503 virt_to_phys() done against the non-linear part of the
2504 kernel's virtual address map.
2508 config TEST_MEMCAT_P
2509 tristate "Test memcat_p() helper function"
2511 Test the memcat_p() helper for correctly merging two
2512 pointer arrays together.
2516 config TEST_LIVEPATCH
2517 tristate "Test livepatching"
2519 depends on DYNAMIC_DEBUG
2520 depends on LIVEPATCH
2523 Test kernel livepatching features for correctness. The tests will
2524 load test modules that will be livepatched in various scenarios.
2526 To run all the livepatching tests:
2528 make -C tools/testing/selftests TARGETS=livepatch run_tests
2530 Alternatively, individual tests may be invoked:
2532 tools/testing/selftests/livepatch/test-callbacks.sh
2533 tools/testing/selftests/livepatch/test-livepatch.sh
2534 tools/testing/selftests/livepatch/test-shadow-vars.sh
2539 tristate "Perform selftest on object aggreration manager"
2543 Enable this option to test object aggregation manager on boot
2547 config TEST_STACKINIT
2548 tristate "Test level of stack variable initialization"
2550 Test if the kernel is zero-initializing stack variables and
2551 padding. Coverage is controlled by compiler flags,
2552 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2553 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2558 tristate "Test heap/page initialization"
2560 Test if the kernel is zero-initializing heap and page allocations.
2561 This can be useful to test init_on_alloc and init_on_free features.
2566 tristate "Test HMM (Heterogeneous Memory Management)"
2567 depends on TRANSPARENT_HUGEPAGE
2568 depends on DEVICE_PRIVATE
2572 This is a pseudo device driver solely for testing HMM.
2573 Say M here if you want to build the HMM test module.
2574 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2578 config TEST_FREE_PAGES
2579 tristate "Test freeing pages"
2581 Test that a memory leak does not occur due to a race between
2582 freeing a block of pages and a speculative page reference.
2583 Loading this module is safe if your kernel has the bug fixed.
2584 If the bug is not fixed, it will leak gigabytes of memory and
2585 probably OOM your system.
2588 tristate "Test floating point operations in kernel space"
2589 depends on X86 && !KCOV_INSTRUMENT_ALL
2591 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2592 which will trigger a sequence of floating point operations. This is used
2593 for self-testing floating point control register setting in
2598 config TEST_CLOCKSOURCE_WATCHDOG
2599 tristate "Test clocksource watchdog in kernel space"
2600 depends on CLOCKSOURCE_WATCHDOG
2602 Enable this option to create a kernel module that will trigger
2603 a test of the clocksource watchdog. This module may be loaded
2604 via modprobe or insmod in which case it will run upon being
2605 loaded, or it may be built in, in which case it will run
2610 endif # RUNTIME_TESTING_MENU
2612 config ARCH_USE_MEMTEST
2615 An architecture should select this when it uses early_memtest()
2616 during boot process.
2620 depends on ARCH_USE_MEMTEST
2622 This option adds a kernel parameter 'memtest', which allows memtest
2623 to be set and executed.
2624 memtest=0, mean disabled; -- default
2625 memtest=1, mean do 1 test pattern;
2627 memtest=17, mean do 17 test patterns.
2628 If you are unsure how to answer this question, answer N.
2632 config HYPERV_TESTING
2633 bool "Microsoft Hyper-V driver testing"
2635 depends on HYPERV && DEBUG_FS
2637 Select this option to enable Hyper-V vmbus testing.
2639 endmenu # "Kernel Testing and Coverage"
2641 source "Documentation/Kconfig"
2643 endmenu # Kernel hacking
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