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 if !PREEMPT_RT
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 if !PREEMPT_RT
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 && !PREEMPT_RT
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 if !PREEMPT_RT
1349 select DEBUG_RT_MUTEXES if PREEMPT_RT
1351 This feature enables slowpath testing for w/w mutex users by
1352 injecting additional -EDEADLK wound/backoff cases. Together with
1353 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1354 will test all possible w/w mutex interface abuse with the
1355 exception of simply not acquiring all the required locks.
1356 Note that this feature can introduce significant overhead, so
1357 it really should not be enabled in a production or distro kernel,
1358 even a debug kernel. If you are a driver writer, enable it. If
1359 you are a distro, do not.
1362 bool "RW Semaphore debugging: basic checks"
1363 depends on DEBUG_KERNEL
1365 This debugging feature allows mismatched rw semaphore locks
1366 and unlocks to be detected and reported.
1368 config DEBUG_LOCK_ALLOC
1369 bool "Lock debugging: detect incorrect freeing of live locks"
1370 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1371 select DEBUG_SPINLOCK
1372 select DEBUG_MUTEXES if !PREEMPT_RT
1373 select DEBUG_RT_MUTEXES if RT_MUTEXES
1376 This feature will check whether any held lock (spinlock, rwlock,
1377 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1378 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1379 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1380 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1381 held during task exit.
1385 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1390 config LOCKDEP_SMALL
1394 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1395 depends on LOCKDEP && !LOCKDEP_SMALL
1399 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1401 config LOCKDEP_CHAINS_BITS
1402 int "Bitsize for MAX_LOCKDEP_CHAINS"
1403 depends on LOCKDEP && !LOCKDEP_SMALL
1407 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1409 config LOCKDEP_STACK_TRACE_BITS
1410 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1411 depends on LOCKDEP && !LOCKDEP_SMALL
1415 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1417 config LOCKDEP_STACK_TRACE_HASH_BITS
1418 int "Bitsize for STACK_TRACE_HASH_SIZE"
1419 depends on LOCKDEP && !LOCKDEP_SMALL
1423 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1425 config LOCKDEP_CIRCULAR_QUEUE_BITS
1426 int "Bitsize for elements in circular_queue struct"
1431 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1433 config DEBUG_LOCKDEP
1434 bool "Lock dependency engine debugging"
1435 depends on DEBUG_KERNEL && LOCKDEP
1436 select DEBUG_IRQFLAGS
1438 If you say Y here, the lock dependency engine will do
1439 additional runtime checks to debug itself, at the price
1440 of more runtime overhead.
1442 config DEBUG_ATOMIC_SLEEP
1443 bool "Sleep inside atomic section checking"
1444 select PREEMPT_COUNT
1445 depends on DEBUG_KERNEL
1446 depends on !ARCH_NO_PREEMPT
1448 If you say Y here, various routines which may sleep will become very
1449 noisy if they are called inside atomic sections: when a spinlock is
1450 held, inside an rcu read side critical section, inside preempt disabled
1451 sections, inside an interrupt, etc...
1453 config DEBUG_LOCKING_API_SELFTESTS
1454 bool "Locking API boot-time self-tests"
1455 depends on DEBUG_KERNEL
1457 Say Y here if you want the kernel to run a short self-test during
1458 bootup. The self-test checks whether common types of locking bugs
1459 are detected by debugging mechanisms or not. (if you disable
1460 lock debugging then those bugs won't be detected of course.)
1461 The following locking APIs are covered: spinlocks, rwlocks,
1464 config LOCK_TORTURE_TEST
1465 tristate "torture tests for locking"
1466 depends on DEBUG_KERNEL
1469 This option provides a kernel module that runs torture tests
1470 on kernel locking primitives. The kernel module may be built
1471 after the fact on the running kernel to be tested, if desired.
1473 Say Y here if you want kernel locking-primitive torture tests
1474 to be built into the kernel.
1475 Say M if you want these torture tests to build as a module.
1476 Say N if you are unsure.
1478 config WW_MUTEX_SELFTEST
1479 tristate "Wait/wound mutex selftests"
1481 This option provides a kernel module that runs tests on the
1482 on the struct ww_mutex locking API.
1484 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1485 with this test harness.
1487 Say M if you want these self tests to build as a module.
1488 Say N if you are unsure.
1490 config SCF_TORTURE_TEST
1491 tristate "torture tests for smp_call_function*()"
1492 depends on DEBUG_KERNEL
1495 This option provides a kernel module that runs torture tests
1496 on the smp_call_function() family of primitives. The kernel
1497 module may be built after the fact on the running kernel to
1498 be tested, if desired.
1500 config CSD_LOCK_WAIT_DEBUG
1501 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1502 depends on DEBUG_KERNEL
1506 This option enables debug prints when CPUs are slow to respond
1507 to the smp_call_function*() IPI wrappers. These debug prints
1508 include the IPI handler function currently executing (if any)
1509 and relevant stack traces.
1511 endmenu # lock debugging
1513 config TRACE_IRQFLAGS
1514 depends on TRACE_IRQFLAGS_SUPPORT
1517 Enables hooks to interrupt enabling and disabling for
1518 either tracing or lock debugging.
1520 config TRACE_IRQFLAGS_NMI
1522 depends on TRACE_IRQFLAGS
1523 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1525 config DEBUG_IRQFLAGS
1526 bool "Debug IRQ flag manipulation"
1528 Enables checks for potentially unsafe enabling or disabling of
1529 interrupts, such as calling raw_local_irq_restore() when interrupts
1533 bool "Stack backtrace support"
1534 depends on STACKTRACE_SUPPORT
1536 This option causes the kernel to create a /proc/pid/stack for
1537 every process, showing its current stack trace.
1538 It is also used by various kernel debugging features that require
1539 stack trace generation.
1541 config WARN_ALL_UNSEEDED_RANDOM
1542 bool "Warn for all uses of unseeded randomness"
1545 Some parts of the kernel contain bugs relating to their use of
1546 cryptographically secure random numbers before it's actually possible
1547 to generate those numbers securely. This setting ensures that these
1548 flaws don't go unnoticed, by enabling a message, should this ever
1549 occur. This will allow people with obscure setups to know when things
1550 are going wrong, so that they might contact developers about fixing
1553 Unfortunately, on some models of some architectures getting
1554 a fully seeded CRNG is extremely difficult, and so this can
1555 result in dmesg getting spammed for a surprisingly long
1556 time. This is really bad from a security perspective, and
1557 so architecture maintainers really need to do what they can
1558 to get the CRNG seeded sooner after the system is booted.
1559 However, since users cannot do anything actionable to
1560 address this, by default the kernel will issue only a single
1561 warning for the first use of unseeded randomness.
1563 Say Y here if you want to receive warnings for all uses of
1564 unseeded randomness. This will be of use primarily for
1565 those developers interested in improving the security of
1566 Linux kernels running on their architecture (or
1569 config DEBUG_KOBJECT
1570 bool "kobject debugging"
1571 depends on DEBUG_KERNEL
1573 If you say Y here, some extra kobject debugging messages will be sent
1576 config DEBUG_KOBJECT_RELEASE
1577 bool "kobject release debugging"
1578 depends on DEBUG_OBJECTS_TIMERS
1580 kobjects are reference counted objects. This means that their
1581 last reference count put is not predictable, and the kobject can
1582 live on past the point at which a driver decides to drop it's
1583 initial reference to the kobject gained on allocation. An
1584 example of this would be a struct device which has just been
1587 However, some buggy drivers assume that after such an operation,
1588 the memory backing the kobject can be immediately freed. This
1589 goes completely against the principles of a refcounted object.
1591 If you say Y here, the kernel will delay the release of kobjects
1592 on the last reference count to improve the visibility of this
1593 kind of kobject release bug.
1595 config HAVE_DEBUG_BUGVERBOSE
1598 menu "Debug kernel data structures"
1601 bool "Debug linked list manipulation"
1602 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1604 Enable this to turn on extended checks in the linked-list
1610 bool "Debug priority linked list manipulation"
1611 depends on DEBUG_KERNEL
1613 Enable this to turn on extended checks in the priority-ordered
1614 linked-list (plist) walking routines. This checks the entire
1615 list multiple times during each manipulation.
1620 bool "Debug SG table operations"
1621 depends on DEBUG_KERNEL
1623 Enable this to turn on checks on scatter-gather tables. This can
1624 help find problems with drivers that do not properly initialize
1629 config DEBUG_NOTIFIERS
1630 bool "Debug notifier call chains"
1631 depends on DEBUG_KERNEL
1633 Enable this to turn on sanity checking for notifier call chains.
1634 This is most useful for kernel developers to make sure that
1635 modules properly unregister themselves from notifier chains.
1636 This is a relatively cheap check but if you care about maximum
1639 config BUG_ON_DATA_CORRUPTION
1640 bool "Trigger a BUG when data corruption is detected"
1643 Select this option if the kernel should BUG when it encounters
1644 data corruption in kernel memory structures when they get checked
1651 config DEBUG_CREDENTIALS
1652 bool "Debug credential management"
1653 depends on DEBUG_KERNEL
1655 Enable this to turn on some debug checking for credential
1656 management. The additional code keeps track of the number of
1657 pointers from task_structs to any given cred struct, and checks to
1658 see that this number never exceeds the usage count of the cred
1661 Furthermore, if SELinux is enabled, this also checks that the
1662 security pointer in the cred struct is never seen to be invalid.
1666 source "kernel/rcu/Kconfig.debug"
1668 config DEBUG_WQ_FORCE_RR_CPU
1669 bool "Force round-robin CPU selection for unbound work items"
1670 depends on DEBUG_KERNEL
1673 Workqueue used to implicitly guarantee that work items queued
1674 without explicit CPU specified are put on the local CPU. This
1675 guarantee is no longer true and while local CPU is still
1676 preferred work items may be put on foreign CPUs. Kernel
1677 parameter "workqueue.debug_force_rr_cpu" is added to force
1678 round-robin CPU selection to flush out usages which depend on the
1679 now broken guarantee. This config option enables the debug
1680 feature by default. When enabled, memory and cache locality will
1683 config CPU_HOTPLUG_STATE_CONTROL
1684 bool "Enable CPU hotplug state control"
1685 depends on DEBUG_KERNEL
1686 depends on HOTPLUG_CPU
1689 Allows to write steps between "offline" and "online" to the CPUs
1690 sysfs target file so states can be stepped granular. This is a debug
1691 option for now as the hotplug machinery cannot be stopped and
1692 restarted at arbitrary points yet.
1694 Say N if your are unsure.
1697 bool "Latency measuring infrastructure"
1698 depends on DEBUG_KERNEL
1699 depends on STACKTRACE_SUPPORT
1701 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1707 Enable this option if you want to use the LatencyTOP tool
1708 to find out which userspace is blocking on what kernel operations.
1710 source "kernel/trace/Kconfig"
1712 config PROVIDE_OHCI1394_DMA_INIT
1713 bool "Remote debugging over FireWire early on boot"
1714 depends on PCI && X86
1716 If you want to debug problems which hang or crash the kernel early
1717 on boot and the crashing machine has a FireWire port, you can use
1718 this feature to remotely access the memory of the crashed machine
1719 over FireWire. This employs remote DMA as part of the OHCI1394
1720 specification which is now the standard for FireWire controllers.
1722 With remote DMA, you can monitor the printk buffer remotely using
1723 firescope and access all memory below 4GB using fireproxy from gdb.
1724 Even controlling a kernel debugger is possible using remote DMA.
1728 If ohci1394_dma=early is used as boot parameter, it will initialize
1729 all OHCI1394 controllers which are found in the PCI config space.
1731 As all changes to the FireWire bus such as enabling and disabling
1732 devices cause a bus reset and thereby disable remote DMA for all
1733 devices, be sure to have the cable plugged and FireWire enabled on
1734 the debugging host before booting the debug target for debugging.
1736 This code (~1k) is freed after boot. By then, the firewire stack
1737 in charge of the OHCI-1394 controllers should be used instead.
1739 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1741 source "samples/Kconfig"
1743 config ARCH_HAS_DEVMEM_IS_ALLOWED
1746 config STRICT_DEVMEM
1747 bool "Filter access to /dev/mem"
1748 depends on MMU && DEVMEM
1749 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1750 default y if PPC || X86 || ARM64
1752 If this option is disabled, you allow userspace (root) access to all
1753 of memory, including kernel and userspace memory. Accidental
1754 access to this is obviously disastrous, but specific access can
1755 be used by people debugging the kernel. Note that with PAT support
1756 enabled, even in this case there are restrictions on /dev/mem
1757 use due to the cache aliasing requirements.
1759 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1760 file only allows userspace access to PCI space and the BIOS code and
1761 data regions. This is sufficient for dosemu and X and all common
1766 config IO_STRICT_DEVMEM
1767 bool "Filter I/O access to /dev/mem"
1768 depends on STRICT_DEVMEM
1770 If this option is disabled, you allow userspace (root) access to all
1771 io-memory regardless of whether a driver is actively using that
1772 range. Accidental access to this is obviously disastrous, but
1773 specific access can be used by people debugging kernel drivers.
1775 If this option is switched on, the /dev/mem file only allows
1776 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1777 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1778 if the driver using a given range cannot be disabled.
1782 menu "$(SRCARCH) Debugging"
1784 source "arch/$(SRCARCH)/Kconfig.debug"
1788 menu "Kernel Testing and Coverage"
1790 source "lib/kunit/Kconfig"
1792 config NOTIFIER_ERROR_INJECTION
1793 tristate "Notifier error injection"
1794 depends on DEBUG_KERNEL
1797 This option provides the ability to inject artificial errors to
1798 specified notifier chain callbacks. It is useful to test the error
1799 handling of notifier call chain failures.
1803 config PM_NOTIFIER_ERROR_INJECT
1804 tristate "PM notifier error injection module"
1805 depends on PM && NOTIFIER_ERROR_INJECTION
1806 default m if PM_DEBUG
1808 This option provides the ability to inject artificial errors to
1809 PM notifier chain callbacks. It is controlled through debugfs
1810 interface /sys/kernel/debug/notifier-error-inject/pm
1812 If the notifier call chain should be failed with some events
1813 notified, write the error code to "actions/<notifier event>/error".
1815 Example: Inject PM suspend error (-12 = -ENOMEM)
1817 # cd /sys/kernel/debug/notifier-error-inject/pm/
1818 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1819 # echo mem > /sys/power/state
1820 bash: echo: write error: Cannot allocate memory
1822 To compile this code as a module, choose M here: the module will
1823 be called pm-notifier-error-inject.
1827 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1828 tristate "OF reconfig notifier error injection module"
1829 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1831 This option provides the ability to inject artificial errors to
1832 OF reconfig notifier chain callbacks. It is controlled
1833 through debugfs interface under
1834 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1836 If the notifier call chain should be failed with some events
1837 notified, write the error code to "actions/<notifier event>/error".
1839 To compile this code as a module, choose M here: the module will
1840 be called of-reconfig-notifier-error-inject.
1844 config NETDEV_NOTIFIER_ERROR_INJECT
1845 tristate "Netdev notifier error injection module"
1846 depends on NET && NOTIFIER_ERROR_INJECTION
1848 This option provides the ability to inject artificial errors to
1849 netdevice notifier chain callbacks. It is controlled through debugfs
1850 interface /sys/kernel/debug/notifier-error-inject/netdev
1852 If the notifier call chain should be failed with some events
1853 notified, write the error code to "actions/<notifier event>/error".
1855 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1857 # cd /sys/kernel/debug/notifier-error-inject/netdev
1858 # echo -22 > actions/NETDEV_CHANGEMTU/error
1859 # ip link set eth0 mtu 1024
1860 RTNETLINK answers: Invalid argument
1862 To compile this code as a module, choose M here: the module will
1863 be called netdev-notifier-error-inject.
1867 config FUNCTION_ERROR_INJECTION
1869 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1871 config FAULT_INJECTION
1872 bool "Fault-injection framework"
1873 depends on DEBUG_KERNEL
1875 Provide fault-injection framework.
1876 For more details, see Documentation/fault-injection/.
1879 bool "Fault-injection capability for kmalloc"
1880 depends on FAULT_INJECTION
1881 depends on SLAB || SLUB
1883 Provide fault-injection capability for kmalloc.
1885 config FAIL_PAGE_ALLOC
1886 bool "Fault-injection capability for alloc_pages()"
1887 depends on FAULT_INJECTION
1889 Provide fault-injection capability for alloc_pages().
1891 config FAULT_INJECTION_USERCOPY
1892 bool "Fault injection capability for usercopy functions"
1893 depends on FAULT_INJECTION
1895 Provides fault-injection capability to inject failures
1896 in usercopy functions (copy_from_user(), get_user(), ...).
1898 config FAIL_MAKE_REQUEST
1899 bool "Fault-injection capability for disk IO"
1900 depends on FAULT_INJECTION && BLOCK
1902 Provide fault-injection capability for disk IO.
1904 config FAIL_IO_TIMEOUT
1905 bool "Fault-injection capability for faking disk interrupts"
1906 depends on FAULT_INJECTION && BLOCK
1908 Provide fault-injection capability on end IO handling. This
1909 will make the block layer "forget" an interrupt as configured,
1910 thus exercising the error handling.
1912 Only works with drivers that use the generic timeout handling,
1913 for others it won't do anything.
1916 bool "Fault-injection capability for futexes"
1918 depends on FAULT_INJECTION && FUTEX
1920 Provide fault-injection capability for futexes.
1922 config FAULT_INJECTION_DEBUG_FS
1923 bool "Debugfs entries for fault-injection capabilities"
1924 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1926 Enable configuration of fault-injection capabilities via debugfs.
1928 config FAIL_FUNCTION
1929 bool "Fault-injection capability for functions"
1930 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1932 Provide function-based fault-injection capability.
1933 This will allow you to override a specific function with a return
1934 with given return value. As a result, function caller will see
1935 an error value and have to handle it. This is useful to test the
1936 error handling in various subsystems.
1938 config FAIL_MMC_REQUEST
1939 bool "Fault-injection capability for MMC IO"
1940 depends on FAULT_INJECTION_DEBUG_FS && MMC
1942 Provide fault-injection capability for MMC IO.
1943 This will make the mmc core return data errors. This is
1944 useful to test the error handling in the mmc block device
1945 and to test how the mmc host driver handles retries from
1949 bool "Fault-injection capability for SunRPC"
1950 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1952 Provide fault-injection capability for SunRPC and
1955 config FAULT_INJECTION_STACKTRACE_FILTER
1956 bool "stacktrace filter for fault-injection capabilities"
1957 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1960 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1962 Provide stacktrace filter for fault-injection capabilities
1964 config ARCH_HAS_KCOV
1967 An architecture should select this when it can successfully
1968 build and run with CONFIG_KCOV. This typically requires
1969 disabling instrumentation for some early boot code.
1971 config CC_HAS_SANCOV_TRACE_PC
1972 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1976 bool "Code coverage for fuzzing"
1977 depends on ARCH_HAS_KCOV
1978 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1980 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1982 KCOV exposes kernel code coverage information in a form suitable
1983 for coverage-guided fuzzing (randomized testing).
1985 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1986 different machines and across reboots. If you need stable PC values,
1987 disable RANDOMIZE_BASE.
1989 For more details, see Documentation/dev-tools/kcov.rst.
1991 config KCOV_ENABLE_COMPARISONS
1992 bool "Enable comparison operands collection by KCOV"
1994 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
1996 KCOV also exposes operands of every comparison in the instrumented
1997 code along with operand sizes and PCs of the comparison instructions.
1998 These operands can be used by fuzzing engines to improve the quality
1999 of fuzzing coverage.
2001 config KCOV_INSTRUMENT_ALL
2002 bool "Instrument all code by default"
2006 If you are doing generic system call fuzzing (like e.g. syzkaller),
2007 then you will want to instrument the whole kernel and you should
2008 say y here. If you are doing more targeted fuzzing (like e.g.
2009 filesystem fuzzing with AFL) then you will want to enable coverage
2010 for more specific subsets of files, and should say n here.
2012 config KCOV_IRQ_AREA_SIZE
2013 hex "Size of interrupt coverage collection area in words"
2017 KCOV uses preallocated per-cpu areas to collect coverage from
2018 soft interrupts. This specifies the size of those areas in the
2019 number of unsigned long words.
2021 menuconfig RUNTIME_TESTING_MENU
2022 bool "Runtime Testing"
2025 if RUNTIME_TESTING_MENU
2028 tristate "Linux Kernel Dump Test Tool Module"
2031 This module enables testing of the different dumping mechanisms by
2032 inducing system failures at predefined crash points.
2033 If you don't need it: say N
2034 Choose M here to compile this code as a module. The module will be
2037 Documentation on how to use the module can be found in
2038 Documentation/fault-injection/provoke-crashes.rst
2040 config TEST_LIST_SORT
2041 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2043 default KUNIT_ALL_TESTS
2045 Enable this to turn on 'list_sort()' function test. This test is
2046 executed only once during system boot (so affects only boot time),
2047 or at module load time.
2051 config TEST_MIN_HEAP
2052 tristate "Min heap test"
2053 depends on DEBUG_KERNEL || m
2055 Enable this to turn on min heap function tests. This test is
2056 executed only once during system boot (so affects only boot time),
2057 or at module load time.
2062 tristate "Array-based sort test"
2063 depends on DEBUG_KERNEL || m
2065 This option enables the self-test function of 'sort()' at boot,
2066 or at module load time.
2071 tristate "64bit/32bit division and modulo test"
2072 depends on DEBUG_KERNEL || m
2074 Enable this to turn on 'do_div()' function test. This test is
2075 executed only once during system boot (so affects only boot time),
2076 or at module load time.
2080 config KPROBES_SANITY_TEST
2081 bool "Kprobes sanity tests"
2082 depends on DEBUG_KERNEL
2085 This option provides for testing basic kprobes functionality on
2086 boot. Samples of kprobe and kretprobe are inserted and
2087 verified for functionality.
2089 Say N if you are unsure.
2091 config BACKTRACE_SELF_TEST
2092 tristate "Self test for the backtrace code"
2093 depends on DEBUG_KERNEL
2095 This option provides a kernel module that can be used to test
2096 the kernel stack backtrace code. This option is not useful
2097 for distributions or general kernels, but only for kernel
2098 developers working on architecture code.
2100 Note that if you want to also test saved backtraces, you will
2101 have to enable STACKTRACE as well.
2103 Say N if you are unsure.
2106 tristate "Red-Black tree test"
2107 depends on DEBUG_KERNEL
2109 A benchmark measuring the performance of the rbtree library.
2110 Also includes rbtree invariant checks.
2112 config REED_SOLOMON_TEST
2113 tristate "Reed-Solomon library test"
2114 depends on DEBUG_KERNEL || m
2116 select REED_SOLOMON_ENC16
2117 select REED_SOLOMON_DEC16
2119 This option enables the self-test function of rslib at boot,
2120 or at module load time.
2124 config INTERVAL_TREE_TEST
2125 tristate "Interval tree test"
2126 depends on DEBUG_KERNEL
2127 select INTERVAL_TREE
2129 A benchmark measuring the performance of the interval tree library
2132 tristate "Per cpu operations test"
2133 depends on m && DEBUG_KERNEL
2135 Enable this option to build test module which validates per-cpu
2140 config ATOMIC64_SELFTEST
2141 tristate "Perform an atomic64_t self-test"
2143 Enable this option to test the atomic64_t functions at boot or
2144 at module load time.
2148 config ASYNC_RAID6_TEST
2149 tristate "Self test for hardware accelerated raid6 recovery"
2150 depends on ASYNC_RAID6_RECOV
2153 This is a one-shot self test that permutes through the
2154 recovery of all the possible two disk failure scenarios for a
2155 N-disk array. Recovery is performed with the asynchronous
2156 raid6 recovery routines, and will optionally use an offload
2157 engine if one is available.
2162 tristate "Test functions located in the hexdump module at runtime"
2164 config STRING_SELFTEST
2165 tristate "Test string functions at runtime"
2167 config TEST_STRING_HELPERS
2168 tristate "Test functions located in the string_helpers module at runtime"
2171 tristate "Test strscpy*() family of functions at runtime"
2174 tristate "Test kstrto*() family of functions at runtime"
2177 tristate "Test printf() family of functions at runtime"
2180 tristate "Test scanf() family of functions at runtime"
2183 tristate "Test bitmap_*() family of functions at runtime"
2185 Enable this option to test the bitmap functions at boot.
2190 tristate "Test functions located in the uuid module at runtime"
2193 tristate "Test the XArray code at runtime"
2195 config TEST_OVERFLOW
2196 tristate "Test check_*_overflow() functions at runtime"
2198 config TEST_RHASHTABLE
2199 tristate "Perform selftest on resizable hash table"
2201 Enable this option to test the rhashtable functions at boot.
2206 tristate "Perform selftest on hash functions"
2208 Enable this option to test the kernel's integer (<linux/hash.h>),
2209 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
2210 hash functions on boot (or module load).
2212 This is intended to help people writing architecture-specific
2213 optimized versions. If unsure, say N.
2216 tristate "Perform selftest on IDA functions"
2219 tristate "Perform selftest on priority array manager"
2222 Enable this option to test priority array manager on boot
2227 config TEST_IRQ_TIMINGS
2228 bool "IRQ timings selftest"
2229 depends on IRQ_TIMINGS
2231 Enable this option to test the irq timings code on boot.
2236 tristate "Test module loading with 'hello world' module"
2239 This builds the "test_module" module that emits "Hello, world"
2240 on printk when loaded. It is designed to be used for basic
2241 evaluation of the module loading subsystem (for example when
2242 validating module verification). It lacks any extra dependencies,
2243 and will not normally be loaded by the system unless explicitly
2249 tristate "Test module for compilation of bitops operations"
2252 This builds the "test_bitops" module that is much like the
2253 TEST_LKM module except that it does a basic exercise of the
2254 set/clear_bit macros and get_count_order/long to make sure there are
2255 no compiler warnings from C=1 sparse checker or -Wextra
2256 compilations. It has no dependencies and doesn't run or load unless
2257 explicitly requested by name. for example: modprobe test_bitops.
2262 tristate "Test module for stress/performance analysis of vmalloc allocator"
2267 This builds the "test_vmalloc" module that should be used for
2268 stress and performance analysis. So, any new change for vmalloc
2269 subsystem can be evaluated from performance and stability point
2274 config TEST_USER_COPY
2275 tristate "Test user/kernel boundary protections"
2278 This builds the "test_user_copy" module that runs sanity checks
2279 on the copy_to/from_user infrastructure, making sure basic
2280 user/kernel boundary testing is working. If it fails to load,
2281 a regression has been detected in the user/kernel memory boundary
2287 tristate "Test BPF filter functionality"
2290 This builds the "test_bpf" module that runs various test vectors
2291 against the BPF interpreter or BPF JIT compiler depending on the
2292 current setting. This is in particular useful for BPF JIT compiler
2293 development, but also to run regression tests against changes in
2294 the interpreter code. It also enables test stubs for eBPF maps and
2295 verifier used by user space verifier testsuite.
2299 config TEST_BLACKHOLE_DEV
2300 tristate "Test blackhole netdev functionality"
2303 This builds the "test_blackhole_dev" module that validates the
2304 data path through this blackhole netdev.
2308 config FIND_BIT_BENCHMARK
2309 tristate "Test find_bit functions"
2311 This builds the "test_find_bit" module that measure find_*_bit()
2312 functions performance.
2316 config TEST_FIRMWARE
2317 tristate "Test firmware loading via userspace interface"
2318 depends on FW_LOADER
2320 This builds the "test_firmware" module that creates a userspace
2321 interface for testing firmware loading. This can be used to
2322 control the triggering of firmware loading without needing an
2323 actual firmware-using device. The contents can be rechecked by
2329 tristate "sysctl test driver"
2330 depends on PROC_SYSCTL
2332 This builds the "test_sysctl" module. This driver enables to test the
2333 proc sysctl interfaces available to drivers safely without affecting
2334 production knobs which might alter system functionality.
2338 config BITFIELD_KUNIT
2339 tristate "KUnit test bitfield functions at runtime"
2342 Enable this option to test the bitfield functions at boot.
2344 KUnit tests run during boot and output the results to the debug log
2345 in TAP format (http://testanything.org/). Only useful for kernel devs
2346 running the KUnit test harness, and not intended for inclusion into a
2349 For more information on KUnit and unit tests in general please refer
2350 to the KUnit documentation in Documentation/dev-tools/kunit/.
2354 config RESOURCE_KUNIT_TEST
2355 tristate "KUnit test for resource API"
2358 This builds the resource API unit test.
2359 Tests the logic of API provided by resource.c and ioport.h.
2360 For more information on KUnit and unit tests in general please refer
2361 to the KUnit documentation in Documentation/dev-tools/kunit/.
2365 config SYSCTL_KUNIT_TEST
2366 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2368 default KUNIT_ALL_TESTS
2370 This builds the proc sysctl unit test, which runs on boot.
2371 Tests the API contract and implementation correctness of sysctl.
2372 For more information on KUnit and unit tests in general please refer
2373 to the KUnit documentation in Documentation/dev-tools/kunit/.
2377 config LIST_KUNIT_TEST
2378 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2380 default KUNIT_ALL_TESTS
2382 This builds the linked list KUnit test suite.
2383 It tests that the API and basic functionality of the list_head type
2384 and associated macros.
2386 KUnit tests run during boot and output the results to the debug log
2387 in TAP format (https://testanything.org/). Only useful for kernel devs
2388 running the KUnit test harness, and not intended for inclusion into a
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 LINEAR_RANGES_TEST
2397 tristate "KUnit test for linear_ranges"
2399 select LINEAR_RANGES
2401 This builds the linear_ranges unit test, which runs on boot.
2402 Tests the linear_ranges logic correctness.
2403 For more information on KUnit and unit tests in general please refer
2404 to the KUnit documentation in Documentation/dev-tools/kunit/.
2408 config CMDLINE_KUNIT_TEST
2409 tristate "KUnit test for cmdline API"
2412 This builds the cmdline API unit test.
2413 Tests the logic of API provided by cmdline.c.
2414 For more information on KUnit and unit tests in general please refer
2415 to the KUnit documentation in Documentation/dev-tools/kunit/.
2420 tristate "KUnit test for bits.h"
2423 This builds the bits unit test.
2424 Tests the logic of macros defined in bits.h.
2425 For more information on KUnit and unit tests in general please refer
2426 to the KUnit documentation in Documentation/dev-tools/kunit/.
2430 config SLUB_KUNIT_TEST
2431 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2432 depends on SLUB_DEBUG && KUNIT
2433 default KUNIT_ALL_TESTS
2435 This builds SLUB allocator unit test.
2436 Tests SLUB cache debugging functionality.
2437 For more information on KUnit and unit tests in general please refer
2438 to the KUnit documentation in Documentation/dev-tools/kunit/.
2442 config RATIONAL_KUNIT_TEST
2443 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2446 default KUNIT_ALL_TESTS
2448 This builds the rational math unit test.
2449 For more information on KUnit and unit tests in general please refer
2450 to the KUnit documentation in Documentation/dev-tools/kunit/.
2455 tristate "udelay test driver"
2457 This builds the "udelay_test" module that helps to make sure
2458 that udelay() is working properly.
2462 config TEST_STATIC_KEYS
2463 tristate "Test static keys"
2466 Test the static key interfaces.
2471 tristate "kmod stress tester"
2473 depends on NETDEVICES && NET_CORE && INET # for TUN
2480 Test the kernel's module loading mechanism: kmod. kmod implements
2481 support to load modules using the Linux kernel's usermode helper.
2482 This test provides a series of tests against kmod.
2484 Although technically you can either build test_kmod as a module or
2485 into the kernel we disallow building it into the kernel since
2486 it stress tests request_module() and this will very likely cause
2487 some issues by taking over precious threads available from other
2488 module load requests, ultimately this could be fatal.
2492 tools/testing/selftests/kmod/kmod.sh --help
2496 config TEST_DEBUG_VIRTUAL
2497 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2498 depends on DEBUG_VIRTUAL
2500 Test the kernel's ability to detect incorrect calls to
2501 virt_to_phys() done against the non-linear part of the
2502 kernel's virtual address map.
2506 config TEST_MEMCAT_P
2507 tristate "Test memcat_p() helper function"
2509 Test the memcat_p() helper for correctly merging two
2510 pointer arrays together.
2514 config TEST_LIVEPATCH
2515 tristate "Test livepatching"
2517 depends on DYNAMIC_DEBUG
2518 depends on LIVEPATCH
2521 Test kernel livepatching features for correctness. The tests will
2522 load test modules that will be livepatched in various scenarios.
2524 To run all the livepatching tests:
2526 make -C tools/testing/selftests TARGETS=livepatch run_tests
2528 Alternatively, individual tests may be invoked:
2530 tools/testing/selftests/livepatch/test-callbacks.sh
2531 tools/testing/selftests/livepatch/test-livepatch.sh
2532 tools/testing/selftests/livepatch/test-shadow-vars.sh
2537 tristate "Perform selftest on object aggreration manager"
2541 Enable this option to test object aggregation manager on boot
2545 config TEST_STACKINIT
2546 tristate "Test level of stack variable initialization"
2548 Test if the kernel is zero-initializing stack variables and
2549 padding. Coverage is controlled by compiler flags,
2550 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2551 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2556 tristate "Test heap/page initialization"
2558 Test if the kernel is zero-initializing heap and page allocations.
2559 This can be useful to test init_on_alloc and init_on_free features.
2564 tristate "Test HMM (Heterogeneous Memory Management)"
2565 depends on TRANSPARENT_HUGEPAGE
2566 depends on DEVICE_PRIVATE
2570 This is a pseudo device driver solely for testing HMM.
2571 Say M here if you want to build the HMM test module.
2572 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2576 config TEST_FREE_PAGES
2577 tristate "Test freeing pages"
2579 Test that a memory leak does not occur due to a race between
2580 freeing a block of pages and a speculative page reference.
2581 Loading this module is safe if your kernel has the bug fixed.
2582 If the bug is not fixed, it will leak gigabytes of memory and
2583 probably OOM your system.
2586 tristate "Test floating point operations in kernel space"
2587 depends on X86 && !KCOV_INSTRUMENT_ALL
2589 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2590 which will trigger a sequence of floating point operations. This is used
2591 for self-testing floating point control register setting in
2596 config TEST_CLOCKSOURCE_WATCHDOG
2597 tristate "Test clocksource watchdog in kernel space"
2598 depends on CLOCKSOURCE_WATCHDOG
2600 Enable this option to create a kernel module that will trigger
2601 a test of the clocksource watchdog. This module may be loaded
2602 via modprobe or insmod in which case it will run upon being
2603 loaded, or it may be built in, in which case it will run
2608 endif # RUNTIME_TESTING_MENU
2610 config ARCH_USE_MEMTEST
2613 An architecture should select this when it uses early_memtest()
2614 during boot process.
2618 depends on ARCH_USE_MEMTEST
2620 This option adds a kernel parameter 'memtest', which allows memtest
2621 to be set and executed.
2622 memtest=0, mean disabled; -- default
2623 memtest=1, mean do 1 test pattern;
2625 memtest=17, mean do 17 test patterns.
2626 If you are unsure how to answer this question, answer N.
2630 config HYPERV_TESTING
2631 bool "Microsoft Hyper-V driver testing"
2633 depends on HYPERV && DEBUG_FS
2635 Select this option to enable Hyper-V vmbus testing.
2637 endmenu # "Kernel Testing and Coverage"
2639 source "Documentation/Kconfig"
2641 endmenu # Kernel hacking
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