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 1280 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
369 Disable some compiler optimizations that tend to generate human unreadable
370 assembler output. This may make the kernel slightly slower, but it helps
371 to keep kernel developers who have to stare a lot at assembler listings
374 config HEADERS_INSTALL
375 bool "Install uapi headers to usr/include"
378 This option will install uapi headers (headers exported to user-space)
379 into the usr/include directory for use during the kernel build.
380 This is unneeded for building the kernel itself, but needed for some
381 user-space program samples. It is also needed by some features such
382 as uapi header sanity checks.
384 config DEBUG_SECTION_MISMATCH
385 bool "Enable full Section mismatch analysis"
387 The section mismatch analysis checks if there are illegal
388 references from one section to another section.
389 During linktime or runtime, some sections are dropped;
390 any use of code/data previously in these sections would
391 most likely result in an oops.
392 In the code, functions and variables are annotated with
393 __init,, etc. (see the full list in include/linux/init.h),
394 which results in the code/data being placed in specific sections.
395 The section mismatch analysis is always performed after a full
396 kernel build, and enabling this option causes the following
397 additional step to occur:
398 - Add the option -fno-inline-functions-called-once to gcc commands.
399 When inlining a function annotated with __init in a non-init
400 function, we would lose the section information and thus
401 the analysis would not catch the illegal reference.
402 This option tells gcc to inline less (but it does result in
405 config SECTION_MISMATCH_WARN_ONLY
406 bool "Make section mismatch errors non-fatal"
409 If you say N here, the build process will fail if there are any
410 section mismatch, instead of just throwing warnings.
414 config DEBUG_FORCE_FUNCTION_ALIGN_64B
415 bool "Force all function address 64B aligned" if EXPERT
417 There are cases that a commit from one domain changes the function
418 address alignment of other domains, and cause magic performance
419 bump (regression or improvement). Enable this option will help to
420 verify if the bump is caused by function alignment changes, while
421 it will slightly increase the kernel size and affect icache usage.
423 It is mainly for debug and performance tuning use.
426 # Select this config option from the architecture Kconfig, if it
427 # is preferred to always offer frame pointers as a config
428 # option on the architecture (regardless of KERNEL_DEBUG):
430 config ARCH_WANT_FRAME_POINTERS
434 bool "Compile the kernel with frame pointers"
435 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
436 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
438 If you say Y here the resulting kernel image will be slightly
439 larger and slower, but it gives very useful debugging information
440 in case of kernel bugs. (precise oopses/stacktraces/warnings)
442 config STACK_VALIDATION
443 bool "Compile-time stack metadata validation"
444 depends on HAVE_STACK_VALIDATION
447 Add compile-time checks to validate stack metadata, including frame
448 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
449 that runtime stack traces are more reliable.
451 This is also a prerequisite for generation of ORC unwind data, which
452 is needed for CONFIG_UNWINDER_ORC.
454 For more information, see
455 tools/objtool/Documentation/stack-validation.txt.
457 config VMLINUX_VALIDATION
459 depends on STACK_VALIDATION && DEBUG_ENTRY && !PARAVIRT
463 bool "Generate vmlinux.map file when linking"
466 Selecting this option will pass "-Map=vmlinux.map" to ld
467 when linking vmlinux. That file can be useful for verifying
468 and debugging magic section games, and for seeing which
469 pieces of code get eliminated with
470 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
472 config DEBUG_FORCE_WEAK_PER_CPU
473 bool "Force weak per-cpu definitions"
474 depends on DEBUG_KERNEL
476 s390 and alpha require percpu variables in modules to be
477 defined weak to work around addressing range issue which
478 puts the following two restrictions on percpu variable
481 1. percpu symbols must be unique whether static or not
482 2. percpu variables can't be defined inside a function
484 To ensure that generic code follows the above rules, this
485 option forces all percpu variables to be defined as weak.
487 endmenu # "Compiler options"
489 menu "Generic Kernel Debugging Instruments"
492 bool "Magic SysRq key"
495 If you say Y here, you will have some control over the system even
496 if the system crashes for example during kernel debugging (e.g., you
497 will be able to flush the buffer cache to disk, reboot the system
498 immediately or dump some status information). This is accomplished
499 by pressing various keys while holding SysRq (Alt+PrintScreen). It
500 also works on a serial console (on PC hardware at least), if you
501 send a BREAK and then within 5 seconds a command keypress. The
502 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
503 Don't say Y unless you really know what this hack does.
505 config MAGIC_SYSRQ_DEFAULT_ENABLE
506 hex "Enable magic SysRq key functions by default"
507 depends on MAGIC_SYSRQ
510 Specifies which SysRq key functions are enabled by default.
511 This may be set to 1 or 0 to enable or disable them all, or
512 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
514 config MAGIC_SYSRQ_SERIAL
515 bool "Enable magic SysRq key over serial"
516 depends on MAGIC_SYSRQ
519 Many embedded boards have a disconnected TTL level serial which can
520 generate some garbage that can lead to spurious false sysrq detects.
521 This option allows you to decide whether you want to enable the
524 config MAGIC_SYSRQ_SERIAL_SEQUENCE
525 string "Char sequence that enables magic SysRq over serial"
526 depends on MAGIC_SYSRQ_SERIAL
529 Specifies a sequence of characters that can follow BREAK to enable
530 SysRq on a serial console.
532 If unsure, leave an empty string and the option will not be enabled.
535 bool "Debug Filesystem"
537 debugfs is a virtual file system that kernel developers use to put
538 debugging files into. Enable this option to be able to read and
539 write to these files.
541 For detailed documentation on the debugfs API, see
542 Documentation/filesystems/.
547 prompt "Debugfs default access"
549 default DEBUG_FS_ALLOW_ALL
551 This selects the default access restrictions for debugfs.
552 It can be overridden with kernel command line option
553 debugfs=[on,no-mount,off]. The restrictions apply for API access
554 and filesystem registration.
556 config DEBUG_FS_ALLOW_ALL
559 No restrictions apply. Both API and filesystem registration
560 is on. This is the normal default operation.
562 config DEBUG_FS_DISALLOW_MOUNT
563 bool "Do not register debugfs as filesystem"
565 The API is open but filesystem is not loaded. Clients can still do
566 their work and read with debug tools that do not need
569 config DEBUG_FS_ALLOW_NONE
572 Access is off. Clients get -PERM when trying to create nodes in
573 debugfs tree and debugfs is not registered as a filesystem.
574 Client can then back-off or continue without debugfs access.
578 source "lib/Kconfig.kgdb"
579 source "lib/Kconfig.ubsan"
580 source "lib/Kconfig.kcsan"
585 bool "Kernel debugging"
587 Say Y here if you are developing drivers or trying to debug and
588 identify kernel problems.
591 bool "Miscellaneous debug code"
593 depends on DEBUG_KERNEL
595 Say Y here if you need to enable miscellaneous debug code that should
596 be under a more specific debug option but isn't.
599 menu "Memory Debugging"
601 source "mm/Kconfig.debug"
604 bool "Debug object operations"
605 depends on DEBUG_KERNEL
607 If you say Y here, additional code will be inserted into the
608 kernel to track the life time of various objects and validate
609 the operations on those objects.
611 config DEBUG_OBJECTS_SELFTEST
612 bool "Debug objects selftest"
613 depends on DEBUG_OBJECTS
615 This enables the selftest of the object debug code.
617 config DEBUG_OBJECTS_FREE
618 bool "Debug objects in freed memory"
619 depends on DEBUG_OBJECTS
621 This enables checks whether a k/v free operation frees an area
622 which contains an object which has not been deactivated
623 properly. This can make kmalloc/kfree-intensive workloads
626 config DEBUG_OBJECTS_TIMERS
627 bool "Debug timer objects"
628 depends on DEBUG_OBJECTS
630 If you say Y here, additional code will be inserted into the
631 timer routines to track the life time of timer objects and
632 validate the timer operations.
634 config DEBUG_OBJECTS_WORK
635 bool "Debug work objects"
636 depends on DEBUG_OBJECTS
638 If you say Y here, additional code will be inserted into the
639 work queue routines to track the life time of work objects and
640 validate the work operations.
642 config DEBUG_OBJECTS_RCU_HEAD
643 bool "Debug RCU callbacks objects"
644 depends on DEBUG_OBJECTS
646 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
648 config DEBUG_OBJECTS_PERCPU_COUNTER
649 bool "Debug percpu counter objects"
650 depends on DEBUG_OBJECTS
652 If you say Y here, additional code will be inserted into the
653 percpu counter routines to track the life time of percpu counter
654 objects and validate the percpu counter operations.
656 config DEBUG_OBJECTS_ENABLE_DEFAULT
657 int "debug_objects bootup default value (0-1)"
660 depends on DEBUG_OBJECTS
662 Debug objects boot parameter default value
665 bool "Debug slab memory allocations"
666 depends on DEBUG_KERNEL && SLAB
668 Say Y here to have the kernel do limited verification on memory
669 allocation as well as poisoning memory on free to catch use of freed
670 memory. This can make kmalloc/kfree-intensive workloads much slower.
673 bool "SLUB debugging on by default"
674 depends on SLUB && SLUB_DEBUG
677 Boot with debugging on by default. SLUB boots by default with
678 the runtime debug capabilities switched off. Enabling this is
679 equivalent to specifying the "slub_debug" parameter on boot.
680 There is no support for more fine grained debug control like
681 possible with slub_debug=xxx. SLUB debugging may be switched
682 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
687 bool "Enable SLUB performance statistics"
688 depends on SLUB && SYSFS
690 SLUB statistics are useful to debug SLUBs allocation behavior in
691 order find ways to optimize the allocator. This should never be
692 enabled for production use since keeping statistics slows down
693 the allocator by a few percentage points. The slabinfo command
694 supports the determination of the most active slabs to figure
695 out which slabs are relevant to a particular load.
696 Try running: slabinfo -DA
698 config HAVE_DEBUG_KMEMLEAK
701 config DEBUG_KMEMLEAK
702 bool "Kernel memory leak detector"
703 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
705 select STACKTRACE if STACKTRACE_SUPPORT
709 Say Y here if you want to enable the memory leak
710 detector. The memory allocation/freeing is traced in a way
711 similar to the Boehm's conservative garbage collector, the
712 difference being that the orphan objects are not freed but
713 only shown in /sys/kernel/debug/kmemleak. Enabling this
714 feature will introduce an overhead to memory
715 allocations. See Documentation/dev-tools/kmemleak.rst for more
718 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
719 of finding leaks due to the slab objects poisoning.
721 In order to access the kmemleak file, debugfs needs to be
722 mounted (usually at /sys/kernel/debug).
724 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
725 int "Kmemleak memory pool size"
726 depends on DEBUG_KMEMLEAK
730 Kmemleak must track all the memory allocations to avoid
731 reporting false positives. Since memory may be allocated or
732 freed before kmemleak is fully initialised, use a static pool
733 of metadata objects to track such callbacks. After kmemleak is
734 fully initialised, this memory pool acts as an emergency one
735 if slab allocations fail.
737 config DEBUG_KMEMLEAK_TEST
738 tristate "Simple test for the kernel memory leak detector"
739 depends on DEBUG_KMEMLEAK && m
741 This option enables a module that explicitly leaks memory.
745 config DEBUG_KMEMLEAK_DEFAULT_OFF
746 bool "Default kmemleak to off"
747 depends on DEBUG_KMEMLEAK
749 Say Y here to disable kmemleak by default. It can then be enabled
750 on the command line via kmemleak=on.
752 config DEBUG_KMEMLEAK_AUTO_SCAN
753 bool "Enable kmemleak auto scan thread on boot up"
755 depends on DEBUG_KMEMLEAK
757 Depending on the cpu, kmemleak scan may be cpu intensive and can
758 stall user tasks at times. This option enables/disables automatic
759 kmemleak scan at boot up.
761 Say N here to disable kmemleak auto scan thread to stop automatic
762 scanning. Disabling this option disables automatic reporting of
767 config DEBUG_STACK_USAGE
768 bool "Stack utilization instrumentation"
769 depends on DEBUG_KERNEL && !IA64
771 Enables the display of the minimum amount of free stack which each
772 task has ever had available in the sysrq-T and sysrq-P debug output.
774 This option will slow down process creation somewhat.
776 config SCHED_STACK_END_CHECK
777 bool "Detect stack corruption on calls to schedule()"
778 depends on DEBUG_KERNEL
781 This option checks for a stack overrun on calls to schedule().
782 If the stack end location is found to be over written always panic as
783 the content of the corrupted region can no longer be trusted.
784 This is to ensure no erroneous behaviour occurs which could result in
785 data corruption or a sporadic crash at a later stage once the region
786 is examined. The runtime overhead introduced is minimal.
788 config ARCH_HAS_DEBUG_VM_PGTABLE
791 An architecture should select this when it can successfully
792 build and run DEBUG_VM_PGTABLE.
796 depends on DEBUG_KERNEL
798 Enable this to turn on extended checks in the virtual-memory system
799 that may impact performance.
803 config DEBUG_VM_VMACACHE
804 bool "Debug VMA caching"
807 Enable this to turn on VMA caching debug information. Doing so
808 can cause significant overhead, so only enable it in non-production
814 bool "Debug VM red-black trees"
817 Enable VM red-black tree debugging information and extra validations.
821 config DEBUG_VM_PGFLAGS
822 bool "Debug page-flags operations"
825 Enables extra validation on page flags operations.
829 config DEBUG_VM_PGTABLE
830 bool "Debug arch page table for semantics compliance"
832 depends on ARCH_HAS_DEBUG_VM_PGTABLE
833 default y if DEBUG_VM
835 This option provides a debug method which can be used to test
836 architecture page table helper functions on various platforms in
837 verifying if they comply with expected generic MM semantics. This
838 will help architecture code in making sure that any changes or
839 new additions of these helpers still conform to expected
840 semantics of the generic MM. Platforms will have to opt in for
841 this through ARCH_HAS_DEBUG_VM_PGTABLE.
845 config ARCH_HAS_DEBUG_VIRTUAL
849 bool "Debug VM translations"
850 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
852 Enable some costly sanity checks in virtual to page code. This can
853 catch mistakes with virt_to_page() and friends.
857 config DEBUG_NOMMU_REGIONS
858 bool "Debug the global anon/private NOMMU mapping region tree"
859 depends on DEBUG_KERNEL && !MMU
861 This option causes the global tree of anonymous and private mapping
862 regions to be regularly checked for invalid topology.
864 config DEBUG_MEMORY_INIT
865 bool "Debug memory initialisation" if EXPERT
868 Enable this for additional checks during memory initialisation.
869 The sanity checks verify aspects of the VM such as the memory model
870 and other information provided by the architecture. Verbose
871 information will be printed at KERN_DEBUG loglevel depending
872 on the mminit_loglevel= command-line option.
876 config MEMORY_NOTIFIER_ERROR_INJECT
877 tristate "Memory hotplug notifier error injection module"
878 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
880 This option provides the ability to inject artificial errors to
881 memory hotplug notifier chain callbacks. It is controlled through
882 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
884 If the notifier call chain should be failed with some events
885 notified, write the error code to "actions/<notifier event>/error".
887 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
889 # cd /sys/kernel/debug/notifier-error-inject/memory
890 # echo -12 > actions/MEM_GOING_OFFLINE/error
891 # echo offline > /sys/devices/system/memory/memoryXXX/state
892 bash: echo: write error: Cannot allocate memory
894 To compile this code as a module, choose M here: the module will
895 be called memory-notifier-error-inject.
899 config DEBUG_PER_CPU_MAPS
900 bool "Debug access to per_cpu maps"
901 depends on DEBUG_KERNEL
904 Say Y to verify that the per_cpu map being accessed has
905 been set up. This adds a fair amount of code to kernel memory
906 and decreases performance.
910 config DEBUG_KMAP_LOCAL
911 bool "Debug kmap_local temporary mappings"
912 depends on DEBUG_KERNEL && KMAP_LOCAL
914 This option enables additional error checking for the kmap_local
915 infrastructure. Disable for production use.
917 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
920 config DEBUG_KMAP_LOCAL_FORCE_MAP
921 bool "Enforce kmap_local temporary mappings"
922 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
924 select DEBUG_KMAP_LOCAL
926 This option enforces temporary mappings through the kmap_local
927 mechanism for non-highmem pages and on non-highmem systems.
928 Disable this for production systems!
931 bool "Highmem debugging"
932 depends on DEBUG_KERNEL && HIGHMEM
933 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
934 select DEBUG_KMAP_LOCAL
936 This option enables additional error checking for high memory
937 systems. Disable for production systems.
939 config HAVE_DEBUG_STACKOVERFLOW
942 config DEBUG_STACKOVERFLOW
943 bool "Check for stack overflows"
944 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
946 Say Y here if you want to check for overflows of kernel, IRQ
947 and exception stacks (if your architecture uses them). This
948 option will show detailed messages if free stack space drops
949 below a certain limit.
951 These kinds of bugs usually occur when call-chains in the
952 kernel get too deep, especially when interrupts are
955 Use this in cases where you see apparently random memory
956 corruption, especially if it appears in 'struct thread_info'
958 If in doubt, say "N".
960 source "lib/Kconfig.kasan"
961 source "lib/Kconfig.kfence"
963 endmenu # "Memory Debugging"
966 bool "Debug shared IRQ handlers"
967 depends on DEBUG_KERNEL
969 Enable this to generate a spurious interrupt just before a shared
970 interrupt handler is deregistered (generating one when registering
971 is currently disabled). Drivers need to handle this correctly. Some
972 don't and need to be caught.
974 menu "Debug Oops, Lockups and Hangs"
979 Say Y here to enable the kernel to panic when it oopses. This
980 has the same effect as setting oops=panic on the kernel command
983 This feature is useful to ensure that the kernel does not do
984 anything erroneous after an oops which could result in data
985 corruption or other issues.
989 config PANIC_ON_OOPS_VALUE
992 default 0 if !PANIC_ON_OOPS
993 default 1 if PANIC_ON_OOPS
999 Set the timeout value (in seconds) until a reboot occurs when
1000 the kernel panics. If n = 0, then we wait forever. A timeout
1001 value n > 0 will wait n seconds before rebooting, while a timeout
1002 value n < 0 will reboot immediately.
1004 config LOCKUP_DETECTOR
1007 config SOFTLOCKUP_DETECTOR
1008 bool "Detect Soft Lockups"
1009 depends on DEBUG_KERNEL && !S390
1010 select LOCKUP_DETECTOR
1012 Say Y here to enable the kernel to act as a watchdog to detect
1015 Softlockups are bugs that cause the kernel to loop in kernel
1016 mode for more than 20 seconds, without giving other tasks a
1017 chance to run. The current stack trace is displayed upon
1018 detection and the system will stay locked up.
1020 config BOOTPARAM_SOFTLOCKUP_PANIC
1021 bool "Panic (Reboot) On Soft Lockups"
1022 depends on SOFTLOCKUP_DETECTOR
1024 Say Y here to enable the kernel to panic on "soft lockups",
1025 which are bugs that cause the kernel to loop in kernel
1026 mode for more than 20 seconds (configurable using the watchdog_thresh
1027 sysctl), without giving other tasks a chance to run.
1029 The panic can be used in combination with panic_timeout,
1030 to cause the system to reboot automatically after a
1031 lockup has been detected. This feature is useful for
1032 high-availability systems that have uptime guarantees and
1033 where a lockup must be resolved ASAP.
1037 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
1039 depends on SOFTLOCKUP_DETECTOR
1041 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
1042 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
1044 config HARDLOCKUP_DETECTOR_PERF
1046 select SOFTLOCKUP_DETECTOR
1049 # Enables a timestamp based low pass filter to compensate for perf based
1050 # hard lockup detection which runs too fast due to turbo modes.
1052 config HARDLOCKUP_CHECK_TIMESTAMP
1056 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1057 # lockup detector rather than the perf based detector.
1059 config HARDLOCKUP_DETECTOR
1060 bool "Detect Hard Lockups"
1061 depends on DEBUG_KERNEL && !S390
1062 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1063 select LOCKUP_DETECTOR
1064 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1065 select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH
1067 Say Y here to enable the kernel to act as a watchdog to detect
1070 Hardlockups are bugs that cause the CPU to loop in kernel mode
1071 for more than 10 seconds, without letting other interrupts have a
1072 chance to run. The current stack trace is displayed upon detection
1073 and the system will stay locked up.
1075 config BOOTPARAM_HARDLOCKUP_PANIC
1076 bool "Panic (Reboot) On Hard Lockups"
1077 depends on HARDLOCKUP_DETECTOR
1079 Say Y here to enable the kernel to panic on "hard lockups",
1080 which are bugs that cause the kernel to loop in kernel
1081 mode with interrupts disabled for more than 10 seconds (configurable
1082 using the watchdog_thresh sysctl).
1086 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
1088 depends on HARDLOCKUP_DETECTOR
1090 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
1091 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
1093 config DETECT_HUNG_TASK
1094 bool "Detect Hung Tasks"
1095 depends on DEBUG_KERNEL
1096 default SOFTLOCKUP_DETECTOR
1098 Say Y here to enable the kernel to detect "hung tasks",
1099 which are bugs that cause the task to be stuck in
1100 uninterruptible "D" state indefinitely.
1102 When a hung task is detected, the kernel will print the
1103 current stack trace (which you should report), but the
1104 task will stay in uninterruptible state. If lockdep is
1105 enabled then all held locks will also be reported. This
1106 feature has negligible overhead.
1108 config DEFAULT_HUNG_TASK_TIMEOUT
1109 int "Default timeout for hung task detection (in seconds)"
1110 depends on DETECT_HUNG_TASK
1113 This option controls the default timeout (in seconds) used
1114 to determine when a task has become non-responsive and should
1117 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1118 sysctl or by writing a value to
1119 /proc/sys/kernel/hung_task_timeout_secs.
1121 A timeout of 0 disables the check. The default is two minutes.
1122 Keeping the default should be fine in most cases.
1124 config BOOTPARAM_HUNG_TASK_PANIC
1125 bool "Panic (Reboot) On Hung Tasks"
1126 depends on DETECT_HUNG_TASK
1128 Say Y here to enable the kernel to panic on "hung tasks",
1129 which are bugs that cause the kernel to leave a task stuck
1130 in uninterruptible "D" state.
1132 The panic can be used in combination with panic_timeout,
1133 to cause the system to reboot automatically after a
1134 hung task has been detected. This feature is useful for
1135 high-availability systems that have uptime guarantees and
1136 where a hung tasks must be resolved ASAP.
1140 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
1142 depends on DETECT_HUNG_TASK
1144 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
1145 default 1 if BOOTPARAM_HUNG_TASK_PANIC
1148 bool "Detect Workqueue Stalls"
1149 depends on DEBUG_KERNEL
1151 Say Y here to enable stall detection on workqueues. If a
1152 worker pool doesn't make forward progress on a pending work
1153 item for over a given amount of time, 30s by default, a
1154 warning message is printed along with dump of workqueue
1155 state. This can be configured through kernel parameter
1156 "workqueue.watchdog_thresh" and its sysfs counterpart.
1159 tristate "Test module to generate lockups"
1162 This builds the "test_lockup" module that helps to make sure
1163 that watchdogs and lockup detectors are working properly.
1165 Depending on module parameters it could emulate soft or hard
1166 lockup, "hung task", or locking arbitrary lock for a long time.
1167 Also it could generate series of lockups with cooling-down periods.
1171 endmenu # "Debug lockups and hangs"
1173 menu "Scheduler Debugging"
1176 bool "Collect scheduler debugging info"
1177 depends on DEBUG_KERNEL && PROC_FS
1180 If you say Y here, the /proc/sched_debug file will be provided
1181 that can help debug the scheduler. The runtime overhead of this
1189 bool "Collect scheduler statistics"
1190 depends on DEBUG_KERNEL && PROC_FS
1193 If you say Y here, additional code will be inserted into the
1194 scheduler and related routines to collect statistics about
1195 scheduler behavior and provide them in /proc/schedstat. These
1196 stats may be useful for both tuning and debugging the scheduler
1197 If you aren't debugging the scheduler or trying to tune a specific
1198 application, you can say N to avoid the very slight overhead
1203 config DEBUG_TIMEKEEPING
1204 bool "Enable extra timekeeping sanity checking"
1206 This option will enable additional timekeeping sanity checks
1207 which may be helpful when diagnosing issues where timekeeping
1208 problems are suspected.
1210 This may include checks in the timekeeping hotpaths, so this
1211 option may have a (very small) performance impact to some
1216 config DEBUG_PREEMPT
1217 bool "Debug preemptible kernel"
1218 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1221 If you say Y here then the kernel will use a debug variant of the
1222 commonly used smp_processor_id() function and will print warnings
1223 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1224 will detect preemption count underflows.
1226 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1228 config LOCK_DEBUGGING_SUPPORT
1230 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1233 config PROVE_LOCKING
1234 bool "Lock debugging: prove locking correctness"
1235 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1237 select DEBUG_SPINLOCK
1238 select DEBUG_MUTEXES
1239 select DEBUG_RT_MUTEXES if RT_MUTEXES
1241 select DEBUG_WW_MUTEX_SLOWPATH
1242 select DEBUG_LOCK_ALLOC
1243 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1244 select TRACE_IRQFLAGS
1247 This feature enables the kernel to prove that all locking
1248 that occurs in the kernel runtime is mathematically
1249 correct: that under no circumstance could an arbitrary (and
1250 not yet triggered) combination of observed locking
1251 sequences (on an arbitrary number of CPUs, running an
1252 arbitrary number of tasks and interrupt contexts) cause a
1255 In short, this feature enables the kernel to report locking
1256 related deadlocks before they actually occur.
1258 The proof does not depend on how hard and complex a
1259 deadlock scenario would be to trigger: how many
1260 participant CPUs, tasks and irq-contexts would be needed
1261 for it to trigger. The proof also does not depend on
1262 timing: if a race and a resulting deadlock is possible
1263 theoretically (no matter how unlikely the race scenario
1264 is), it will be proven so and will immediately be
1265 reported by the kernel (once the event is observed that
1266 makes the deadlock theoretically possible).
1268 If a deadlock is impossible (i.e. the locking rules, as
1269 observed by the kernel, are mathematically correct), the
1270 kernel reports nothing.
1272 NOTE: this feature can also be enabled for rwlocks, mutexes
1273 and rwsems - in which case all dependencies between these
1274 different locking variants are observed and mapped too, and
1275 the proof of observed correctness is also maintained for an
1276 arbitrary combination of these separate locking variants.
1278 For more details, see Documentation/locking/lockdep-design.rst.
1280 config PROVE_RAW_LOCK_NESTING
1281 bool "Enable raw_spinlock - spinlock nesting checks"
1282 depends on PROVE_LOCKING
1285 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1286 that the lock nesting rules for PREEMPT_RT enabled kernels are
1289 NOTE: There are known nesting problems. So if you enable this
1290 option expect lockdep splats until these problems have been fully
1291 addressed which is work in progress. This config switch allows to
1292 identify and analyze these problems. It will be removed and the
1293 check permanently enabled once the main issues have been fixed.
1295 If unsure, select N.
1298 bool "Lock usage statistics"
1299 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1301 select DEBUG_SPINLOCK
1302 select DEBUG_MUTEXES
1303 select DEBUG_RT_MUTEXES if RT_MUTEXES
1304 select DEBUG_LOCK_ALLOC
1307 This feature enables tracking lock contention points
1309 For more details, see Documentation/locking/lockstat.rst
1311 This also enables lock events required by "perf lock",
1313 If you want to use "perf lock", you also need to turn on
1314 CONFIG_EVENT_TRACING.
1316 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1317 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1319 config DEBUG_RT_MUTEXES
1320 bool "RT Mutex debugging, deadlock detection"
1321 depends on DEBUG_KERNEL && RT_MUTEXES
1323 This allows rt mutex semantics violations and rt mutex related
1324 deadlocks (lockups) to be detected and reported automatically.
1326 config DEBUG_SPINLOCK
1327 bool "Spinlock and rw-lock debugging: basic checks"
1328 depends on DEBUG_KERNEL
1329 select UNINLINE_SPIN_UNLOCK
1331 Say Y here and build SMP to catch missing spinlock initialization
1332 and certain other kinds of spinlock errors commonly made. This is
1333 best used in conjunction with the NMI watchdog so that spinlock
1334 deadlocks are also debuggable.
1336 config DEBUG_MUTEXES
1337 bool "Mutex debugging: basic checks"
1338 depends on DEBUG_KERNEL
1340 This feature allows mutex semantics violations to be detected and
1343 config DEBUG_WW_MUTEX_SLOWPATH
1344 bool "Wait/wound mutex debugging: Slowpath testing"
1345 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1346 select DEBUG_LOCK_ALLOC
1347 select DEBUG_SPINLOCK
1348 select DEBUG_MUTEXES
1350 This feature enables slowpath testing for w/w mutex users by
1351 injecting additional -EDEADLK wound/backoff cases. Together with
1352 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1353 will test all possible w/w mutex interface abuse with the
1354 exception of simply not acquiring all the required locks.
1355 Note that this feature can introduce significant overhead, so
1356 it really should not be enabled in a production or distro kernel,
1357 even a debug kernel. If you are a driver writer, enable it. If
1358 you are a distro, do not.
1361 bool "RW Semaphore debugging: basic checks"
1362 depends on DEBUG_KERNEL
1364 This debugging feature allows mismatched rw semaphore locks
1365 and unlocks to be detected and reported.
1367 config DEBUG_LOCK_ALLOC
1368 bool "Lock debugging: detect incorrect freeing of live locks"
1369 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1370 select DEBUG_SPINLOCK
1371 select DEBUG_MUTEXES
1372 select DEBUG_RT_MUTEXES if RT_MUTEXES
1375 This feature will check whether any held lock (spinlock, rwlock,
1376 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1377 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1378 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1379 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1380 held during task exit.
1384 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1389 config LOCKDEP_SMALL
1393 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1394 depends on LOCKDEP && !LOCKDEP_SMALL
1398 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1400 config LOCKDEP_CHAINS_BITS
1401 int "Bitsize for MAX_LOCKDEP_CHAINS"
1402 depends on LOCKDEP && !LOCKDEP_SMALL
1406 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1408 config LOCKDEP_STACK_TRACE_BITS
1409 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1410 depends on LOCKDEP && !LOCKDEP_SMALL
1414 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1416 config LOCKDEP_STACK_TRACE_HASH_BITS
1417 int "Bitsize for STACK_TRACE_HASH_SIZE"
1418 depends on LOCKDEP && !LOCKDEP_SMALL
1422 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1424 config LOCKDEP_CIRCULAR_QUEUE_BITS
1425 int "Bitsize for elements in circular_queue struct"
1430 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1432 config DEBUG_LOCKDEP
1433 bool "Lock dependency engine debugging"
1434 depends on DEBUG_KERNEL && LOCKDEP
1435 select DEBUG_IRQFLAGS
1437 If you say Y here, the lock dependency engine will do
1438 additional runtime checks to debug itself, at the price
1439 of more runtime overhead.
1441 config DEBUG_ATOMIC_SLEEP
1442 bool "Sleep inside atomic section checking"
1443 select PREEMPT_COUNT
1444 depends on DEBUG_KERNEL
1445 depends on !ARCH_NO_PREEMPT
1447 If you say Y here, various routines which may sleep will become very
1448 noisy if they are called inside atomic sections: when a spinlock is
1449 held, inside an rcu read side critical section, inside preempt disabled
1450 sections, inside an interrupt, etc...
1452 config DEBUG_LOCKING_API_SELFTESTS
1453 bool "Locking API boot-time self-tests"
1454 depends on DEBUG_KERNEL
1456 Say Y here if you want the kernel to run a short self-test during
1457 bootup. The self-test checks whether common types of locking bugs
1458 are detected by debugging mechanisms or not. (if you disable
1459 lock debugging then those bugs won't be detected of course.)
1460 The following locking APIs are covered: spinlocks, rwlocks,
1463 config LOCK_TORTURE_TEST
1464 tristate "torture tests for locking"
1465 depends on DEBUG_KERNEL
1468 This option provides a kernel module that runs torture tests
1469 on kernel locking primitives. The kernel module may be built
1470 after the fact on the running kernel to be tested, if desired.
1472 Say Y here if you want kernel locking-primitive torture tests
1473 to be built into the kernel.
1474 Say M if you want these torture tests to build as a module.
1475 Say N if you are unsure.
1477 config WW_MUTEX_SELFTEST
1478 tristate "Wait/wound mutex selftests"
1480 This option provides a kernel module that runs tests on the
1481 on the struct ww_mutex locking API.
1483 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1484 with this test harness.
1486 Say M if you want these self tests to build as a module.
1487 Say N if you are unsure.
1489 config SCF_TORTURE_TEST
1490 tristate "torture tests for smp_call_function*()"
1491 depends on DEBUG_KERNEL
1494 This option provides a kernel module that runs torture tests
1495 on the smp_call_function() family of primitives. The kernel
1496 module may be built after the fact on the running kernel to
1497 be tested, if desired.
1499 config CSD_LOCK_WAIT_DEBUG
1500 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1501 depends on DEBUG_KERNEL
1505 This option enables debug prints when CPUs are slow to respond
1506 to the smp_call_function*() IPI wrappers. These debug prints
1507 include the IPI handler function currently executing (if any)
1508 and relevant stack traces.
1510 endmenu # lock debugging
1512 config TRACE_IRQFLAGS
1513 depends on TRACE_IRQFLAGS_SUPPORT
1516 Enables hooks to interrupt enabling and disabling for
1517 either tracing or lock debugging.
1519 config TRACE_IRQFLAGS_NMI
1521 depends on TRACE_IRQFLAGS
1522 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1524 config DEBUG_IRQFLAGS
1525 bool "Debug IRQ flag manipulation"
1527 Enables checks for potentially unsafe enabling or disabling of
1528 interrupts, such as calling raw_local_irq_restore() when interrupts
1532 bool "Stack backtrace support"
1533 depends on STACKTRACE_SUPPORT
1535 This option causes the kernel to create a /proc/pid/stack for
1536 every process, showing its current stack trace.
1537 It is also used by various kernel debugging features that require
1538 stack trace generation.
1540 config WARN_ALL_UNSEEDED_RANDOM
1541 bool "Warn for all uses of unseeded randomness"
1544 Some parts of the kernel contain bugs relating to their use of
1545 cryptographically secure random numbers before it's actually possible
1546 to generate those numbers securely. This setting ensures that these
1547 flaws don't go unnoticed, by enabling a message, should this ever
1548 occur. This will allow people with obscure setups to know when things
1549 are going wrong, so that they might contact developers about fixing
1552 Unfortunately, on some models of some architectures getting
1553 a fully seeded CRNG is extremely difficult, and so this can
1554 result in dmesg getting spammed for a surprisingly long
1555 time. This is really bad from a security perspective, and
1556 so architecture maintainers really need to do what they can
1557 to get the CRNG seeded sooner after the system is booted.
1558 However, since users cannot do anything actionable to
1559 address this, by default the kernel will issue only a single
1560 warning for the first use of unseeded randomness.
1562 Say Y here if you want to receive warnings for all uses of
1563 unseeded randomness. This will be of use primarily for
1564 those developers interested in improving the security of
1565 Linux kernels running on their architecture (or
1568 config DEBUG_KOBJECT
1569 bool "kobject debugging"
1570 depends on DEBUG_KERNEL
1572 If you say Y here, some extra kobject debugging messages will be sent
1575 config DEBUG_KOBJECT_RELEASE
1576 bool "kobject release debugging"
1577 depends on DEBUG_OBJECTS_TIMERS
1579 kobjects are reference counted objects. This means that their
1580 last reference count put is not predictable, and the kobject can
1581 live on past the point at which a driver decides to drop it's
1582 initial reference to the kobject gained on allocation. An
1583 example of this would be a struct device which has just been
1586 However, some buggy drivers assume that after such an operation,
1587 the memory backing the kobject can be immediately freed. This
1588 goes completely against the principles of a refcounted object.
1590 If you say Y here, the kernel will delay the release of kobjects
1591 on the last reference count to improve the visibility of this
1592 kind of kobject release bug.
1594 config HAVE_DEBUG_BUGVERBOSE
1597 menu "Debug kernel data structures"
1600 bool "Debug linked list manipulation"
1601 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1603 Enable this to turn on extended checks in the linked-list
1609 bool "Debug priority linked list manipulation"
1610 depends on DEBUG_KERNEL
1612 Enable this to turn on extended checks in the priority-ordered
1613 linked-list (plist) walking routines. This checks the entire
1614 list multiple times during each manipulation.
1619 bool "Debug SG table operations"
1620 depends on DEBUG_KERNEL
1622 Enable this to turn on checks on scatter-gather tables. This can
1623 help find problems with drivers that do not properly initialize
1628 config DEBUG_NOTIFIERS
1629 bool "Debug notifier call chains"
1630 depends on DEBUG_KERNEL
1632 Enable this to turn on sanity checking for notifier call chains.
1633 This is most useful for kernel developers to make sure that
1634 modules properly unregister themselves from notifier chains.
1635 This is a relatively cheap check but if you care about maximum
1638 config BUG_ON_DATA_CORRUPTION
1639 bool "Trigger a BUG when data corruption is detected"
1642 Select this option if the kernel should BUG when it encounters
1643 data corruption in kernel memory structures when they get checked
1650 config DEBUG_CREDENTIALS
1651 bool "Debug credential management"
1652 depends on DEBUG_KERNEL
1654 Enable this to turn on some debug checking for credential
1655 management. The additional code keeps track of the number of
1656 pointers from task_structs to any given cred struct, and checks to
1657 see that this number never exceeds the usage count of the cred
1660 Furthermore, if SELinux is enabled, this also checks that the
1661 security pointer in the cred struct is never seen to be invalid.
1665 source "kernel/rcu/Kconfig.debug"
1667 config DEBUG_WQ_FORCE_RR_CPU
1668 bool "Force round-robin CPU selection for unbound work items"
1669 depends on DEBUG_KERNEL
1672 Workqueue used to implicitly guarantee that work items queued
1673 without explicit CPU specified are put on the local CPU. This
1674 guarantee is no longer true and while local CPU is still
1675 preferred work items may be put on foreign CPUs. Kernel
1676 parameter "workqueue.debug_force_rr_cpu" is added to force
1677 round-robin CPU selection to flush out usages which depend on the
1678 now broken guarantee. This config option enables the debug
1679 feature by default. When enabled, memory and cache locality will
1682 config DEBUG_BLOCK_EXT_DEVT
1683 bool "Force extended block device numbers and spread them"
1684 depends on DEBUG_KERNEL
1688 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1689 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1690 YOU ARE DOING. Distros, please enable this and fix whatever
1693 Conventionally, block device numbers are allocated from
1694 predetermined contiguous area. However, extended block area
1695 may introduce non-contiguous block device numbers. This
1696 option forces most block device numbers to be allocated from
1697 the extended space and spreads them to discover kernel or
1698 userland code paths which assume predetermined contiguous
1699 device number allocation.
1701 Note that turning on this debug option shuffles all the
1702 device numbers for all IDE and SCSI devices including libata
1703 ones, so root partition specified using device number
1704 directly (via rdev or root=MAJ:MIN) won't work anymore.
1705 Textual device names (root=/dev/sdXn) will continue to work.
1707 Say N if you are unsure.
1709 config CPU_HOTPLUG_STATE_CONTROL
1710 bool "Enable CPU hotplug state control"
1711 depends on DEBUG_KERNEL
1712 depends on HOTPLUG_CPU
1715 Allows to write steps between "offline" and "online" to the CPUs
1716 sysfs target file so states can be stepped granular. This is a debug
1717 option for now as the hotplug machinery cannot be stopped and
1718 restarted at arbitrary points yet.
1720 Say N if your are unsure.
1723 bool "Latency measuring infrastructure"
1724 depends on DEBUG_KERNEL
1725 depends on STACKTRACE_SUPPORT
1727 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1733 Enable this option if you want to use the LatencyTOP tool
1734 to find out which userspace is blocking on what kernel operations.
1736 source "kernel/trace/Kconfig"
1738 config PROVIDE_OHCI1394_DMA_INIT
1739 bool "Remote debugging over FireWire early on boot"
1740 depends on PCI && X86
1742 If you want to debug problems which hang or crash the kernel early
1743 on boot and the crashing machine has a FireWire port, you can use
1744 this feature to remotely access the memory of the crashed machine
1745 over FireWire. This employs remote DMA as part of the OHCI1394
1746 specification which is now the standard for FireWire controllers.
1748 With remote DMA, you can monitor the printk buffer remotely using
1749 firescope and access all memory below 4GB using fireproxy from gdb.
1750 Even controlling a kernel debugger is possible using remote DMA.
1754 If ohci1394_dma=early is used as boot parameter, it will initialize
1755 all OHCI1394 controllers which are found in the PCI config space.
1757 As all changes to the FireWire bus such as enabling and disabling
1758 devices cause a bus reset and thereby disable remote DMA for all
1759 devices, be sure to have the cable plugged and FireWire enabled on
1760 the debugging host before booting the debug target for debugging.
1762 This code (~1k) is freed after boot. By then, the firewire stack
1763 in charge of the OHCI-1394 controllers should be used instead.
1765 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1767 source "samples/Kconfig"
1769 config ARCH_HAS_DEVMEM_IS_ALLOWED
1772 config STRICT_DEVMEM
1773 bool "Filter access to /dev/mem"
1774 depends on MMU && DEVMEM
1775 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1776 default y if PPC || X86 || ARM64
1778 If this option is disabled, you allow userspace (root) access to all
1779 of memory, including kernel and userspace memory. Accidental
1780 access to this is obviously disastrous, but specific access can
1781 be used by people debugging the kernel. Note that with PAT support
1782 enabled, even in this case there are restrictions on /dev/mem
1783 use due to the cache aliasing requirements.
1785 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1786 file only allows userspace access to PCI space and the BIOS code and
1787 data regions. This is sufficient for dosemu and X and all common
1792 config IO_STRICT_DEVMEM
1793 bool "Filter I/O access to /dev/mem"
1794 depends on STRICT_DEVMEM
1796 If this option is disabled, you allow userspace (root) access to all
1797 io-memory regardless of whether a driver is actively using that
1798 range. Accidental access to this is obviously disastrous, but
1799 specific access can be used by people debugging kernel drivers.
1801 If this option is switched on, the /dev/mem file only allows
1802 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1803 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1804 if the driver using a given range cannot be disabled.
1808 menu "$(SRCARCH) Debugging"
1810 source "arch/$(SRCARCH)/Kconfig.debug"
1814 menu "Kernel Testing and Coverage"
1816 source "lib/kunit/Kconfig"
1818 config NOTIFIER_ERROR_INJECTION
1819 tristate "Notifier error injection"
1820 depends on DEBUG_KERNEL
1823 This option provides the ability to inject artificial errors to
1824 specified notifier chain callbacks. It is useful to test the error
1825 handling of notifier call chain failures.
1829 config PM_NOTIFIER_ERROR_INJECT
1830 tristate "PM notifier error injection module"
1831 depends on PM && NOTIFIER_ERROR_INJECTION
1832 default m if PM_DEBUG
1834 This option provides the ability to inject artificial errors to
1835 PM notifier chain callbacks. It is controlled through debugfs
1836 interface /sys/kernel/debug/notifier-error-inject/pm
1838 If the notifier call chain should be failed with some events
1839 notified, write the error code to "actions/<notifier event>/error".
1841 Example: Inject PM suspend error (-12 = -ENOMEM)
1843 # cd /sys/kernel/debug/notifier-error-inject/pm/
1844 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1845 # echo mem > /sys/power/state
1846 bash: echo: write error: Cannot allocate memory
1848 To compile this code as a module, choose M here: the module will
1849 be called pm-notifier-error-inject.
1853 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1854 tristate "OF reconfig notifier error injection module"
1855 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1857 This option provides the ability to inject artificial errors to
1858 OF reconfig notifier chain callbacks. It is controlled
1859 through debugfs interface under
1860 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1862 If the notifier call chain should be failed with some events
1863 notified, write the error code to "actions/<notifier event>/error".
1865 To compile this code as a module, choose M here: the module will
1866 be called of-reconfig-notifier-error-inject.
1870 config NETDEV_NOTIFIER_ERROR_INJECT
1871 tristate "Netdev notifier error injection module"
1872 depends on NET && NOTIFIER_ERROR_INJECTION
1874 This option provides the ability to inject artificial errors to
1875 netdevice notifier chain callbacks. It is controlled through debugfs
1876 interface /sys/kernel/debug/notifier-error-inject/netdev
1878 If the notifier call chain should be failed with some events
1879 notified, write the error code to "actions/<notifier event>/error".
1881 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1883 # cd /sys/kernel/debug/notifier-error-inject/netdev
1884 # echo -22 > actions/NETDEV_CHANGEMTU/error
1885 # ip link set eth0 mtu 1024
1886 RTNETLINK answers: Invalid argument
1888 To compile this code as a module, choose M here: the module will
1889 be called netdev-notifier-error-inject.
1893 config FUNCTION_ERROR_INJECTION
1895 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1897 config FAULT_INJECTION
1898 bool "Fault-injection framework"
1899 depends on DEBUG_KERNEL
1901 Provide fault-injection framework.
1902 For more details, see Documentation/fault-injection/.
1905 bool "Fault-injection capability for kmalloc"
1906 depends on FAULT_INJECTION
1907 depends on SLAB || SLUB
1909 Provide fault-injection capability for kmalloc.
1911 config FAIL_PAGE_ALLOC
1912 bool "Fault-injection capability for alloc_pages()"
1913 depends on FAULT_INJECTION
1915 Provide fault-injection capability for alloc_pages().
1917 config FAULT_INJECTION_USERCOPY
1918 bool "Fault injection capability for usercopy functions"
1919 depends on FAULT_INJECTION
1921 Provides fault-injection capability to inject failures
1922 in usercopy functions (copy_from_user(), get_user(), ...).
1924 config FAIL_MAKE_REQUEST
1925 bool "Fault-injection capability for disk IO"
1926 depends on FAULT_INJECTION && BLOCK
1928 Provide fault-injection capability for disk IO.
1930 config FAIL_IO_TIMEOUT
1931 bool "Fault-injection capability for faking disk interrupts"
1932 depends on FAULT_INJECTION && BLOCK
1934 Provide fault-injection capability on end IO handling. This
1935 will make the block layer "forget" an interrupt as configured,
1936 thus exercising the error handling.
1938 Only works with drivers that use the generic timeout handling,
1939 for others it won't do anything.
1942 bool "Fault-injection capability for futexes"
1944 depends on FAULT_INJECTION && FUTEX
1946 Provide fault-injection capability for futexes.
1948 config FAULT_INJECTION_DEBUG_FS
1949 bool "Debugfs entries for fault-injection capabilities"
1950 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1952 Enable configuration of fault-injection capabilities via debugfs.
1954 config FAIL_FUNCTION
1955 bool "Fault-injection capability for functions"
1956 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1958 Provide function-based fault-injection capability.
1959 This will allow you to override a specific function with a return
1960 with given return value. As a result, function caller will see
1961 an error value and have to handle it. This is useful to test the
1962 error handling in various subsystems.
1964 config FAIL_MMC_REQUEST
1965 bool "Fault-injection capability for MMC IO"
1966 depends on FAULT_INJECTION_DEBUG_FS && MMC
1968 Provide fault-injection capability for MMC IO.
1969 This will make the mmc core return data errors. This is
1970 useful to test the error handling in the mmc block device
1971 and to test how the mmc host driver handles retries from
1974 config FAULT_INJECTION_STACKTRACE_FILTER
1975 bool "stacktrace filter for fault-injection capabilities"
1976 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1979 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1981 Provide stacktrace filter for fault-injection capabilities
1983 config ARCH_HAS_KCOV
1986 An architecture should select this when it can successfully
1987 build and run with CONFIG_KCOV. This typically requires
1988 disabling instrumentation for some early boot code.
1990 config CC_HAS_SANCOV_TRACE_PC
1991 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1995 bool "Code coverage for fuzzing"
1996 depends on ARCH_HAS_KCOV
1997 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1999 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2001 KCOV exposes kernel code coverage information in a form suitable
2002 for coverage-guided fuzzing (randomized testing).
2004 If RANDOMIZE_BASE is enabled, PC values will not be stable across
2005 different machines and across reboots. If you need stable PC values,
2006 disable RANDOMIZE_BASE.
2008 For more details, see Documentation/dev-tools/kcov.rst.
2010 config KCOV_ENABLE_COMPARISONS
2011 bool "Enable comparison operands collection by KCOV"
2013 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2015 KCOV also exposes operands of every comparison in the instrumented
2016 code along with operand sizes and PCs of the comparison instructions.
2017 These operands can be used by fuzzing engines to improve the quality
2018 of fuzzing coverage.
2020 config KCOV_INSTRUMENT_ALL
2021 bool "Instrument all code by default"
2025 If you are doing generic system call fuzzing (like e.g. syzkaller),
2026 then you will want to instrument the whole kernel and you should
2027 say y here. If you are doing more targeted fuzzing (like e.g.
2028 filesystem fuzzing with AFL) then you will want to enable coverage
2029 for more specific subsets of files, and should say n here.
2031 config KCOV_IRQ_AREA_SIZE
2032 hex "Size of interrupt coverage collection area in words"
2036 KCOV uses preallocated per-cpu areas to collect coverage from
2037 soft interrupts. This specifies the size of those areas in the
2038 number of unsigned long words.
2040 menuconfig RUNTIME_TESTING_MENU
2041 bool "Runtime Testing"
2044 if RUNTIME_TESTING_MENU
2047 tristate "Linux Kernel Dump Test Tool Module"
2050 This module enables testing of the different dumping mechanisms by
2051 inducing system failures at predefined crash points.
2052 If you don't need it: say N
2053 Choose M here to compile this code as a module. The module will be
2056 Documentation on how to use the module can be found in
2057 Documentation/fault-injection/provoke-crashes.rst
2059 config TEST_LIST_SORT
2060 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2062 default KUNIT_ALL_TESTS
2064 Enable this to turn on 'list_sort()' function test. This test is
2065 executed only once during system boot (so affects only boot time),
2066 or at module load time.
2070 config TEST_MIN_HEAP
2071 tristate "Min heap test"
2072 depends on DEBUG_KERNEL || m
2074 Enable this to turn on min heap function tests. This test is
2075 executed only once during system boot (so affects only boot time),
2076 or at module load time.
2081 tristate "Array-based sort test"
2082 depends on DEBUG_KERNEL || m
2084 This option enables the self-test function of 'sort()' at boot,
2085 or at module load time.
2090 tristate "64bit/32bit division and modulo test"
2091 depends on DEBUG_KERNEL || m
2093 Enable this to turn on 'do_div()' function test. This test is
2094 executed only once during system boot (so affects only boot time),
2095 or at module load time.
2099 config KPROBES_SANITY_TEST
2100 bool "Kprobes sanity tests"
2101 depends on DEBUG_KERNEL
2104 This option provides for testing basic kprobes functionality on
2105 boot. Samples of kprobe and kretprobe are inserted and
2106 verified for functionality.
2108 Say N if you are unsure.
2110 config BACKTRACE_SELF_TEST
2111 tristate "Self test for the backtrace code"
2112 depends on DEBUG_KERNEL
2114 This option provides a kernel module that can be used to test
2115 the kernel stack backtrace code. This option is not useful
2116 for distributions or general kernels, but only for kernel
2117 developers working on architecture code.
2119 Note that if you want to also test saved backtraces, you will
2120 have to enable STACKTRACE as well.
2122 Say N if you are unsure.
2125 tristate "Red-Black tree test"
2126 depends on DEBUG_KERNEL
2128 A benchmark measuring the performance of the rbtree library.
2129 Also includes rbtree invariant checks.
2131 config REED_SOLOMON_TEST
2132 tristate "Reed-Solomon library test"
2133 depends on DEBUG_KERNEL || m
2135 select REED_SOLOMON_ENC16
2136 select REED_SOLOMON_DEC16
2138 This option enables the self-test function of rslib at boot,
2139 or at module load time.
2143 config INTERVAL_TREE_TEST
2144 tristate "Interval tree test"
2145 depends on DEBUG_KERNEL
2146 select INTERVAL_TREE
2148 A benchmark measuring the performance of the interval tree library
2151 tristate "Per cpu operations test"
2152 depends on m && DEBUG_KERNEL
2154 Enable this option to build test module which validates per-cpu
2159 config ATOMIC64_SELFTEST
2160 tristate "Perform an atomic64_t self-test"
2162 Enable this option to test the atomic64_t functions at boot or
2163 at module load time.
2167 config ASYNC_RAID6_TEST
2168 tristate "Self test for hardware accelerated raid6 recovery"
2169 depends on ASYNC_RAID6_RECOV
2172 This is a one-shot self test that permutes through the
2173 recovery of all the possible two disk failure scenarios for a
2174 N-disk array. Recovery is performed with the asynchronous
2175 raid6 recovery routines, and will optionally use an offload
2176 engine if one is available.
2181 tristate "Test functions located in the hexdump module at runtime"
2183 config STRING_SELFTEST
2184 tristate "Test string functions at runtime"
2186 config TEST_STRING_HELPERS
2187 tristate "Test functions located in the string_helpers module at runtime"
2190 tristate "Test strscpy*() family of functions at runtime"
2193 tristate "Test kstrto*() family of functions at runtime"
2196 tristate "Test printf() family of functions at runtime"
2199 tristate "Test scanf() family of functions at runtime"
2202 tristate "Test bitmap_*() family of functions at runtime"
2204 Enable this option to test the bitmap functions at boot.
2209 tristate "Test functions located in the uuid module at runtime"
2212 tristate "Test the XArray code at runtime"
2214 config TEST_OVERFLOW
2215 tristate "Test check_*_overflow() functions at runtime"
2217 config TEST_RHASHTABLE
2218 tristate "Perform selftest on resizable hash table"
2220 Enable this option to test the rhashtable functions at boot.
2225 tristate "Perform selftest on hash functions"
2227 Enable this option to test the kernel's integer (<linux/hash.h>),
2228 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
2229 hash functions on boot (or module load).
2231 This is intended to help people writing architecture-specific
2232 optimized versions. If unsure, say N.
2235 tristate "Perform selftest on IDA functions"
2238 tristate "Perform selftest on priority array manager"
2241 Enable this option to test priority array manager on boot
2246 config TEST_IRQ_TIMINGS
2247 bool "IRQ timings selftest"
2248 depends on IRQ_TIMINGS
2250 Enable this option to test the irq timings code on boot.
2255 tristate "Test module loading with 'hello world' module"
2258 This builds the "test_module" module that emits "Hello, world"
2259 on printk when loaded. It is designed to be used for basic
2260 evaluation of the module loading subsystem (for example when
2261 validating module verification). It lacks any extra dependencies,
2262 and will not normally be loaded by the system unless explicitly
2268 tristate "Test module for compilation of bitops operations"
2271 This builds the "test_bitops" module that is much like the
2272 TEST_LKM module except that it does a basic exercise of the
2273 set/clear_bit macros and get_count_order/long to make sure there are
2274 no compiler warnings from C=1 sparse checker or -Wextra
2275 compilations. It has no dependencies and doesn't run or load unless
2276 explicitly requested by name. for example: modprobe test_bitops.
2281 tristate "Test module for stress/performance analysis of vmalloc allocator"
2286 This builds the "test_vmalloc" module that should be used for
2287 stress and performance analysis. So, any new change for vmalloc
2288 subsystem can be evaluated from performance and stability point
2293 config TEST_USER_COPY
2294 tristate "Test user/kernel boundary protections"
2297 This builds the "test_user_copy" module that runs sanity checks
2298 on the copy_to/from_user infrastructure, making sure basic
2299 user/kernel boundary testing is working. If it fails to load,
2300 a regression has been detected in the user/kernel memory boundary
2306 tristate "Test BPF filter functionality"
2309 This builds the "test_bpf" module that runs various test vectors
2310 against the BPF interpreter or BPF JIT compiler depending on the
2311 current setting. This is in particular useful for BPF JIT compiler
2312 development, but also to run regression tests against changes in
2313 the interpreter code. It also enables test stubs for eBPF maps and
2314 verifier used by user space verifier testsuite.
2318 config TEST_BLACKHOLE_DEV
2319 tristate "Test blackhole netdev functionality"
2322 This builds the "test_blackhole_dev" module that validates the
2323 data path through this blackhole netdev.
2327 config FIND_BIT_BENCHMARK
2328 tristate "Test find_bit functions"
2330 This builds the "test_find_bit" module that measure find_*_bit()
2331 functions performance.
2335 config TEST_FIRMWARE
2336 tristate "Test firmware loading via userspace interface"
2337 depends on FW_LOADER
2339 This builds the "test_firmware" module that creates a userspace
2340 interface for testing firmware loading. This can be used to
2341 control the triggering of firmware loading without needing an
2342 actual firmware-using device. The contents can be rechecked by
2348 tristate "sysctl test driver"
2349 depends on PROC_SYSCTL
2351 This builds the "test_sysctl" module. This driver enables to test the
2352 proc sysctl interfaces available to drivers safely without affecting
2353 production knobs which might alter system functionality.
2357 config BITFIELD_KUNIT
2358 tristate "KUnit test bitfield functions at runtime"
2361 Enable this option to test the bitfield functions at boot.
2363 KUnit tests run during boot and output the results to the debug log
2364 in TAP format (http://testanything.org/). Only useful for kernel devs
2365 running the KUnit test harness, and not intended for inclusion into a
2368 For more information on KUnit and unit tests in general please refer
2369 to the KUnit documentation in Documentation/dev-tools/kunit/.
2373 config RESOURCE_KUNIT_TEST
2374 tristate "KUnit test for resource API"
2377 This builds the resource API unit test.
2378 Tests the logic of API provided by resource.c and ioport.h.
2379 For more information on KUnit and unit tests in general please refer
2380 to the KUnit documentation in Documentation/dev-tools/kunit/.
2384 config SYSCTL_KUNIT_TEST
2385 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2387 default KUNIT_ALL_TESTS
2389 This builds the proc sysctl unit test, which runs on boot.
2390 Tests the API contract and implementation correctness of sysctl.
2391 For more information on KUnit and unit tests in general please refer
2392 to the KUnit documentation in Documentation/dev-tools/kunit/.
2396 config LIST_KUNIT_TEST
2397 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2399 default KUNIT_ALL_TESTS
2401 This builds the linked list KUnit test suite.
2402 It tests that the API and basic functionality of the list_head type
2403 and associated macros.
2405 KUnit tests run during boot and output the results to the debug log
2406 in TAP format (https://testanything.org/). Only useful for kernel devs
2407 running the KUnit test harness, and not intended for inclusion into a
2410 For more information on KUnit and unit tests in general please refer
2411 to the KUnit documentation in Documentation/dev-tools/kunit/.
2415 config LINEAR_RANGES_TEST
2416 tristate "KUnit test for linear_ranges"
2418 select LINEAR_RANGES
2420 This builds the linear_ranges unit test, which runs on boot.
2421 Tests the linear_ranges logic correctness.
2422 For more information on KUnit and unit tests in general please refer
2423 to the KUnit documentation in Documentation/dev-tools/kunit/.
2427 config CMDLINE_KUNIT_TEST
2428 tristate "KUnit test for cmdline API"
2431 This builds the cmdline API unit test.
2432 Tests the logic of API provided by cmdline.c.
2433 For more information on KUnit and unit tests in general please refer
2434 to the KUnit documentation in Documentation/dev-tools/kunit/.
2439 tristate "KUnit test for bits.h"
2442 This builds the bits unit test.
2443 Tests the logic of macros defined in bits.h.
2444 For more information on KUnit and unit tests in general please refer
2445 to the KUnit documentation in Documentation/dev-tools/kunit/.
2449 config SLUB_KUNIT_TEST
2450 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2451 depends on SLUB_DEBUG && KUNIT
2452 default KUNIT_ALL_TESTS
2454 This builds SLUB allocator unit test.
2455 Tests SLUB cache debugging functionality.
2456 For more information on KUnit and unit tests in general please refer
2457 to the KUnit documentation in Documentation/dev-tools/kunit/.
2461 config RATIONAL_KUNIT_TEST
2462 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2465 default KUNIT_ALL_TESTS
2467 This builds the rational math unit test.
2468 For more information on KUnit and unit tests in general please refer
2469 to the KUnit documentation in Documentation/dev-tools/kunit/.
2474 tristate "udelay test driver"
2476 This builds the "udelay_test" module that helps to make sure
2477 that udelay() is working properly.
2481 config TEST_STATIC_KEYS
2482 tristate "Test static keys"
2485 Test the static key interfaces.
2490 tristate "kmod stress tester"
2492 depends on NETDEVICES && NET_CORE && INET # for TUN
2499 Test the kernel's module loading mechanism: kmod. kmod implements
2500 support to load modules using the Linux kernel's usermode helper.
2501 This test provides a series of tests against kmod.
2503 Although technically you can either build test_kmod as a module or
2504 into the kernel we disallow building it into the kernel since
2505 it stress tests request_module() and this will very likely cause
2506 some issues by taking over precious threads available from other
2507 module load requests, ultimately this could be fatal.
2511 tools/testing/selftests/kmod/kmod.sh --help
2515 config TEST_DEBUG_VIRTUAL
2516 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2517 depends on DEBUG_VIRTUAL
2519 Test the kernel's ability to detect incorrect calls to
2520 virt_to_phys() done against the non-linear part of the
2521 kernel's virtual address map.
2525 config TEST_MEMCAT_P
2526 tristate "Test memcat_p() helper function"
2528 Test the memcat_p() helper for correctly merging two
2529 pointer arrays together.
2533 config TEST_LIVEPATCH
2534 tristate "Test livepatching"
2536 depends on DYNAMIC_DEBUG
2537 depends on LIVEPATCH
2540 Test kernel livepatching features for correctness. The tests will
2541 load test modules that will be livepatched in various scenarios.
2543 To run all the livepatching tests:
2545 make -C tools/testing/selftests TARGETS=livepatch run_tests
2547 Alternatively, individual tests may be invoked:
2549 tools/testing/selftests/livepatch/test-callbacks.sh
2550 tools/testing/selftests/livepatch/test-livepatch.sh
2551 tools/testing/selftests/livepatch/test-shadow-vars.sh
2556 tristate "Perform selftest on object aggreration manager"
2560 Enable this option to test object aggregation manager on boot
2564 config TEST_STACKINIT
2565 tristate "Test level of stack variable initialization"
2567 Test if the kernel is zero-initializing stack variables and
2568 padding. Coverage is controlled by compiler flags,
2569 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2570 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2575 tristate "Test heap/page initialization"
2577 Test if the kernel is zero-initializing heap and page allocations.
2578 This can be useful to test init_on_alloc and init_on_free features.
2583 tristate "Test HMM (Heterogeneous Memory Management)"
2584 depends on TRANSPARENT_HUGEPAGE
2585 depends on DEVICE_PRIVATE
2589 This is a pseudo device driver solely for testing HMM.
2590 Say M here if you want to build the HMM test module.
2591 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2595 config TEST_FREE_PAGES
2596 tristate "Test freeing pages"
2598 Test that a memory leak does not occur due to a race between
2599 freeing a block of pages and a speculative page reference.
2600 Loading this module is safe if your kernel has the bug fixed.
2601 If the bug is not fixed, it will leak gigabytes of memory and
2602 probably OOM your system.
2605 tristate "Test floating point operations in kernel space"
2606 depends on X86 && !KCOV_INSTRUMENT_ALL
2608 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2609 which will trigger a sequence of floating point operations. This is used
2610 for self-testing floating point control register setting in
2615 config TEST_CLOCKSOURCE_WATCHDOG
2616 tristate "Test clocksource watchdog in kernel space"
2617 depends on CLOCKSOURCE_WATCHDOG
2619 Enable this option to create a kernel module that will trigger
2620 a test of the clocksource watchdog. This module may be loaded
2621 via modprobe or insmod in which case it will run upon being
2622 loaded, or it may be built in, in which case it will run
2627 endif # RUNTIME_TESTING_MENU
2629 config ARCH_USE_MEMTEST
2632 An architecture should select this when it uses early_memtest()
2633 during boot process.
2637 depends on ARCH_USE_MEMTEST
2639 This option adds a kernel parameter 'memtest', which allows memtest
2640 to be set and executed.
2641 memtest=0, mean disabled; -- default
2642 memtest=1, mean do 1 test pattern;
2644 memtest=17, mean do 17 test patterns.
2645 If you are unsure how to answer this question, answer N.
2649 config HYPERV_TESTING
2650 bool "Microsoft Hyper-V driver testing"
2652 depends on HYPERV && DEBUG_FS
2654 Select this option to enable Hyper-V vmbus testing.
2656 endmenu # "Kernel Testing and Coverage"
2658 source "Documentation/Kconfig"
2660 endmenu # Kernel hacking
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