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 CONSOLE_LOGLEVEL_DEFAULT
39 int "Default console loglevel (1-15)"
43 Default loglevel to determine what will be printed on the console.
45 Setting a default here is equivalent to passing in loglevel=<x> in
46 the kernel bootargs. loglevel=<x> continues to override whatever
47 value is specified here as well.
49 Note: This does not affect the log level of un-prefixed printk()
50 usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
53 config CONSOLE_LOGLEVEL_QUIET
54 int "quiet console loglevel (1-15)"
58 loglevel to use when "quiet" is passed on the kernel commandline.
60 When "quiet" is passed on the kernel commandline this loglevel
61 will be used as the loglevel. IOW passing "quiet" will be the
62 equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
64 config MESSAGE_LOGLEVEL_DEFAULT
65 int "Default message log level (1-7)"
69 Default log level for printk statements with no specified priority.
71 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
72 that are auditing their logs closely may want to set it to a lower
75 Note: This does not affect what message level gets printed on the console
76 by default. To change that, use loglevel=<x> in the kernel bootargs,
77 or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
79 config BOOT_PRINTK_DELAY
80 bool "Delay each boot printk message by N milliseconds"
81 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
83 This build option allows you to read kernel boot messages
84 by inserting a short delay after each one. The delay is
85 specified in milliseconds on the kernel command line,
88 It is likely that you would also need to use "lpj=M" to preset
89 the "loops per jiffie" value.
90 See a previous boot log for the "lpj" value to use for your
91 system, and then set "lpj=M" before setting "boot_delay=N".
92 NOTE: Using this option may adversely affect SMP systems.
93 I.e., processors other than the first one may not boot up.
94 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
95 what it believes to be lockup conditions.
98 bool "Enable dynamic printk() support"
101 depends on (DEBUG_FS || PROC_FS)
102 select DYNAMIC_DEBUG_CORE
105 Compiles debug level messages into the kernel, which would not
106 otherwise be available at runtime. These messages can then be
107 enabled/disabled based on various levels of scope - per source file,
108 function, module, format string, and line number. This mechanism
109 implicitly compiles in all pr_debug() and dev_dbg() calls, which
110 enlarges the kernel text size by about 2%.
112 If a source file is compiled with DEBUG flag set, any
113 pr_debug() calls in it are enabled by default, but can be
114 disabled at runtime as below. Note that DEBUG flag is
115 turned on by many CONFIG_*DEBUG* options.
119 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
120 which is contained in the 'debugfs' filesystem or procfs.
121 Thus, the debugfs or procfs filesystem must first be mounted before
122 making use of this feature.
123 We refer the control file as: <debugfs>/dynamic_debug/control. This
124 file contains a list of the debug statements that can be enabled. The
125 format for each line of the file is:
127 filename:lineno [module]function flags format
129 filename : source file of the debug statement
130 lineno : line number of the debug statement
131 module : module that contains the debug statement
132 function : function that contains the debug statement
133 flags : '=p' means the line is turned 'on' for printing
134 format : the format used for the debug statement
138 nullarbor:~ # cat <debugfs>/dynamic_debug/control
139 # filename:lineno [module]function flags format
140 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
141 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
142 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
146 // enable the message at line 1603 of file svcsock.c
147 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
148 <debugfs>/dynamic_debug/control
150 // enable all the messages in file svcsock.c
151 nullarbor:~ # echo -n 'file svcsock.c +p' >
152 <debugfs>/dynamic_debug/control
154 // enable all the messages in the NFS server module
155 nullarbor:~ # echo -n 'module nfsd +p' >
156 <debugfs>/dynamic_debug/control
158 // enable all 12 messages in the function svc_process()
159 nullarbor:~ # echo -n 'func svc_process +p' >
160 <debugfs>/dynamic_debug/control
162 // disable all 12 messages in the function svc_process()
163 nullarbor:~ # echo -n 'func svc_process -p' >
164 <debugfs>/dynamic_debug/control
166 See Documentation/admin-guide/dynamic-debug-howto.rst for additional
169 config DYNAMIC_DEBUG_CORE
170 bool "Enable core function of dynamic debug support"
172 depends on (DEBUG_FS || PROC_FS)
174 Enable core functional support of dynamic debug. It is useful
175 when you want to tie dynamic debug to your kernel modules with
176 DYNAMIC_DEBUG_MODULE defined for each of them, especially for
177 the case of embedded system where the kernel image size is
178 sensitive for people.
180 config SYMBOLIC_ERRNAME
181 bool "Support symbolic error names in printf"
184 If you say Y here, the kernel's printf implementation will
185 be able to print symbolic error names such as ENOSPC instead
186 of the number 28. It makes the kernel image slightly larger
187 (about 3KB), but can make the kernel logs easier to read.
189 config DEBUG_BUGVERBOSE
190 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
191 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
194 Say Y here to make BUG() panics output the file name and line number
195 of the BUG call as well as the EIP and oops trace. This aids
196 debugging but costs about 70-100K of memory.
198 endmenu # "printk and dmesg options"
200 menu "Compile-time checks and compiler options"
203 bool "Compile the kernel with debug info"
204 depends on DEBUG_KERNEL && !COMPILE_TEST
206 If you say Y here the resulting kernel image will include
207 debugging info resulting in a larger kernel image.
208 This adds debug symbols to the kernel and modules (gcc -g), and
209 is needed if you intend to use kernel crashdump or binary object
210 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
211 Say Y here only if you plan to debug the kernel.
217 config DEBUG_INFO_REDUCED
218 bool "Reduce debugging information"
220 If you say Y here gcc is instructed to generate less debugging
221 information for structure types. This means that tools that
222 need full debugging information (like kgdb or systemtap) won't
223 be happy. But if you merely need debugging information to
224 resolve line numbers there is no loss. Advantage is that
225 build directory object sizes shrink dramatically over a full
226 DEBUG_INFO build and compile times are reduced too.
227 Only works with newer gcc versions.
229 config DEBUG_INFO_COMPRESSED
230 bool "Compressed debugging information"
231 depends on $(cc-option,-gz=zlib)
232 depends on $(ld-option,--compress-debug-sections=zlib)
234 Compress the debug information using zlib. Requires GCC 5.0+ or Clang
235 5.0+, binutils 2.26+, and zlib.
237 Users of dpkg-deb via scripts/package/builddeb may find an increase in
238 size of their debug .deb packages with this config set, due to the
239 debug info being compressed with zlib, then the object files being
240 recompressed with a different compression scheme. But this is still
241 preferable to setting $KDEB_COMPRESS to "none" which would be even
244 config DEBUG_INFO_SPLIT
245 bool "Produce split debuginfo in .dwo files"
246 depends on $(cc-option,-gsplit-dwarf)
248 Generate debug info into separate .dwo files. This significantly
249 reduces the build directory size for builds with DEBUG_INFO,
250 because it stores the information only once on disk in .dwo
251 files instead of multiple times in object files and executables.
252 In addition the debug information is also compressed.
254 Requires recent gcc (4.7+) and recent gdb/binutils.
255 Any tool that packages or reads debug information would need
256 to know about the .dwo files and include them.
257 Incompatible with older versions of ccache.
259 config DEBUG_INFO_DWARF4
260 bool "Generate dwarf4 debuginfo"
261 depends on $(cc-option,-gdwarf-4)
263 Generate dwarf4 debug info. This requires recent versions
264 of gcc and gdb. It makes the debug information larger.
265 But it significantly improves the success of resolving
266 variables in gdb on optimized code.
268 config DEBUG_INFO_BTF
269 bool "Generate BTF typeinfo"
270 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
271 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
273 Generate deduplicated BTF type information from DWARF debug info.
274 Turning this on expects presence of pahole tool, which will convert
275 DWARF type info into equivalent deduplicated BTF type info.
278 bool "Provide GDB scripts for kernel debugging"
280 This creates the required links to GDB helper scripts in the
281 build directory. If you load vmlinux into gdb, the helper
282 scripts will be automatically imported by gdb as well, and
283 additional functions are available to analyze a Linux kernel
284 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
289 config ENABLE_MUST_CHECK
290 bool "Enable __must_check logic"
293 Enable the __must_check logic in the kernel build. Disable this to
294 suppress the "warning: ignoring return value of 'foo', declared with
295 attribute warn_unused_result" messages.
298 int "Warn for stack frames larger than"
300 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
301 default 2048 if PARISC
302 default 1536 if (!64BIT && XTENSA)
303 default 1280 if KASAN && !64BIT
304 default 1024 if !64BIT
305 default 2048 if 64BIT
307 Tell gcc to warn at build time for stack frames larger than this.
308 Setting this too low will cause a lot of warnings.
309 Setting it to 0 disables the warning.
311 config STRIP_ASM_SYMS
312 bool "Strip assembler-generated symbols during link"
315 Strip internal assembler-generated symbols during a link (symbols
316 that look like '.Lxxx') so they don't pollute the output of
317 get_wchan() and suchlike.
320 bool "Generate readable assembler code"
321 depends on DEBUG_KERNEL
323 Disable some compiler optimizations that tend to generate human unreadable
324 assembler output. This may make the kernel slightly slower, but it helps
325 to keep kernel developers who have to stare a lot at assembler listings
328 config HEADERS_INSTALL
329 bool "Install uapi headers to usr/include"
332 This option will install uapi headers (headers exported to user-space)
333 into the usr/include directory for use during the kernel build.
334 This is unneeded for building the kernel itself, but needed for some
335 user-space program samples. It is also needed by some features such
336 as uapi header sanity checks.
338 config DEBUG_SECTION_MISMATCH
339 bool "Enable full Section mismatch analysis"
341 The section mismatch analysis checks if there are illegal
342 references from one section to another section.
343 During linktime or runtime, some sections are dropped;
344 any use of code/data previously in these sections would
345 most likely result in an oops.
346 In the code, functions and variables are annotated with
347 __init,, etc. (see the full list in include/linux/init.h),
348 which results in the code/data being placed in specific sections.
349 The section mismatch analysis is always performed after a full
350 kernel build, and enabling this option causes the following
351 additional step to occur:
352 - Add the option -fno-inline-functions-called-once to gcc commands.
353 When inlining a function annotated with __init in a non-init
354 function, we would lose the section information and thus
355 the analysis would not catch the illegal reference.
356 This option tells gcc to inline less (but it does result in
359 config SECTION_MISMATCH_WARN_ONLY
360 bool "Make section mismatch errors non-fatal"
363 If you say N here, the build process will fail if there are any
364 section mismatch, instead of just throwing warnings.
368 config DEBUG_FORCE_FUNCTION_ALIGN_32B
369 bool "Force all function address 32B aligned" if EXPERT
371 There are cases that a commit from one domain changes the function
372 address alignment of other domains, and cause magic performance
373 bump (regression or improvement). Enable this option will help to
374 verify if the bump is caused by function alignment changes, while
375 it will slightly increase the kernel size and affect icache usage.
377 It is mainly for debug and performance tuning use.
380 # Select this config option from the architecture Kconfig, if it
381 # is preferred to always offer frame pointers as a config
382 # option on the architecture (regardless of KERNEL_DEBUG):
384 config ARCH_WANT_FRAME_POINTERS
388 bool "Compile the kernel with frame pointers"
389 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
390 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
392 If you say Y here the resulting kernel image will be slightly
393 larger and slower, but it gives very useful debugging information
394 in case of kernel bugs. (precise oopses/stacktraces/warnings)
396 config STACK_VALIDATION
397 bool "Compile-time stack metadata validation"
398 depends on HAVE_STACK_VALIDATION
401 Add compile-time checks to validate stack metadata, including frame
402 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
403 that runtime stack traces are more reliable.
405 This is also a prerequisite for generation of ORC unwind data, which
406 is needed for CONFIG_UNWINDER_ORC.
408 For more information, see
409 tools/objtool/Documentation/stack-validation.txt.
411 config VMLINUX_VALIDATION
413 depends on STACK_VALIDATION && DEBUG_ENTRY && !PARAVIRT
416 config DEBUG_FORCE_WEAK_PER_CPU
417 bool "Force weak per-cpu definitions"
418 depends on DEBUG_KERNEL
420 s390 and alpha require percpu variables in modules to be
421 defined weak to work around addressing range issue which
422 puts the following two restrictions on percpu variable
425 1. percpu symbols must be unique whether static or not
426 2. percpu variables can't be defined inside a function
428 To ensure that generic code follows the above rules, this
429 option forces all percpu variables to be defined as weak.
431 endmenu # "Compiler options"
433 menu "Generic Kernel Debugging Instruments"
436 bool "Magic SysRq key"
439 If you say Y here, you will have some control over the system even
440 if the system crashes for example during kernel debugging (e.g., you
441 will be able to flush the buffer cache to disk, reboot the system
442 immediately or dump some status information). This is accomplished
443 by pressing various keys while holding SysRq (Alt+PrintScreen). It
444 also works on a serial console (on PC hardware at least), if you
445 send a BREAK and then within 5 seconds a command keypress. The
446 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
447 Don't say Y unless you really know what this hack does.
449 config MAGIC_SYSRQ_DEFAULT_ENABLE
450 hex "Enable magic SysRq key functions by default"
451 depends on MAGIC_SYSRQ
454 Specifies which SysRq key functions are enabled by default.
455 This may be set to 1 or 0 to enable or disable them all, or
456 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
458 config MAGIC_SYSRQ_SERIAL
459 bool "Enable magic SysRq key over serial"
460 depends on MAGIC_SYSRQ
463 Many embedded boards have a disconnected TTL level serial which can
464 generate some garbage that can lead to spurious false sysrq detects.
465 This option allows you to decide whether you want to enable the
468 config MAGIC_SYSRQ_SERIAL_SEQUENCE
469 string "Char sequence that enables magic SysRq over serial"
470 depends on MAGIC_SYSRQ_SERIAL
473 Specifies a sequence of characters that can follow BREAK to enable
474 SysRq on a serial console.
476 If unsure, leave an empty string and the option will not be enabled.
479 bool "Debug Filesystem"
481 debugfs is a virtual file system that kernel developers use to put
482 debugging files into. Enable this option to be able to read and
483 write to these files.
485 For detailed documentation on the debugfs API, see
486 Documentation/filesystems/.
491 prompt "Debugfs default access"
493 default DEBUG_FS_ALLOW_ALL
495 This selects the default access restrictions for debugfs.
496 It can be overridden with kernel command line option
497 debugfs=[on,no-mount,off]. The restrictions apply for API access
498 and filesystem registration.
500 config DEBUG_FS_ALLOW_ALL
503 No restrictions apply. Both API and filesystem registration
504 is on. This is the normal default operation.
506 config DEBUG_FS_DISALLOW_MOUNT
507 bool "Do not register debugfs as filesystem"
509 The API is open but filesystem is not loaded. Clients can still do
510 their work and read with debug tools that do not need
513 config DEBUG_FS_ALLOW_NONE
516 Access is off. Clients get -PERM when trying to create nodes in
517 debugfs tree and debugfs is not registered as a filesystem.
518 Client can then back-off or continue without debugfs access.
522 source "lib/Kconfig.kgdb"
523 source "lib/Kconfig.ubsan"
524 source "lib/Kconfig.kcsan"
529 bool "Kernel debugging"
531 Say Y here if you are developing drivers or trying to debug and
532 identify kernel problems.
535 bool "Miscellaneous debug code"
537 depends on DEBUG_KERNEL
539 Say Y here if you need to enable miscellaneous debug code that should
540 be under a more specific debug option but isn't.
543 menu "Memory Debugging"
545 source "mm/Kconfig.debug"
548 bool "Debug object operations"
549 depends on DEBUG_KERNEL
551 If you say Y here, additional code will be inserted into the
552 kernel to track the life time of various objects and validate
553 the operations on those objects.
555 config DEBUG_OBJECTS_SELFTEST
556 bool "Debug objects selftest"
557 depends on DEBUG_OBJECTS
559 This enables the selftest of the object debug code.
561 config DEBUG_OBJECTS_FREE
562 bool "Debug objects in freed memory"
563 depends on DEBUG_OBJECTS
565 This enables checks whether a k/v free operation frees an area
566 which contains an object which has not been deactivated
567 properly. This can make kmalloc/kfree-intensive workloads
570 config DEBUG_OBJECTS_TIMERS
571 bool "Debug timer objects"
572 depends on DEBUG_OBJECTS
574 If you say Y here, additional code will be inserted into the
575 timer routines to track the life time of timer objects and
576 validate the timer operations.
578 config DEBUG_OBJECTS_WORK
579 bool "Debug work objects"
580 depends on DEBUG_OBJECTS
582 If you say Y here, additional code will be inserted into the
583 work queue routines to track the life time of work objects and
584 validate the work operations.
586 config DEBUG_OBJECTS_RCU_HEAD
587 bool "Debug RCU callbacks objects"
588 depends on DEBUG_OBJECTS
590 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
592 config DEBUG_OBJECTS_PERCPU_COUNTER
593 bool "Debug percpu counter objects"
594 depends on DEBUG_OBJECTS
596 If you say Y here, additional code will be inserted into the
597 percpu counter routines to track the life time of percpu counter
598 objects and validate the percpu counter operations.
600 config DEBUG_OBJECTS_ENABLE_DEFAULT
601 int "debug_objects bootup default value (0-1)"
604 depends on DEBUG_OBJECTS
606 Debug objects boot parameter default value
609 bool "Debug slab memory allocations"
610 depends on DEBUG_KERNEL && SLAB
612 Say Y here to have the kernel do limited verification on memory
613 allocation as well as poisoning memory on free to catch use of freed
614 memory. This can make kmalloc/kfree-intensive workloads much slower.
617 bool "SLUB debugging on by default"
618 depends on SLUB && SLUB_DEBUG
621 Boot with debugging on by default. SLUB boots by default with
622 the runtime debug capabilities switched off. Enabling this is
623 equivalent to specifying the "slub_debug" parameter on boot.
624 There is no support for more fine grained debug control like
625 possible with slub_debug=xxx. SLUB debugging may be switched
626 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
631 bool "Enable SLUB performance statistics"
632 depends on SLUB && SYSFS
634 SLUB statistics are useful to debug SLUBs allocation behavior in
635 order find ways to optimize the allocator. This should never be
636 enabled for production use since keeping statistics slows down
637 the allocator by a few percentage points. The slabinfo command
638 supports the determination of the most active slabs to figure
639 out which slabs are relevant to a particular load.
640 Try running: slabinfo -DA
642 config HAVE_DEBUG_KMEMLEAK
645 config DEBUG_KMEMLEAK
646 bool "Kernel memory leak detector"
647 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
649 select STACKTRACE if STACKTRACE_SUPPORT
653 Say Y here if you want to enable the memory leak
654 detector. The memory allocation/freeing is traced in a way
655 similar to the Boehm's conservative garbage collector, the
656 difference being that the orphan objects are not freed but
657 only shown in /sys/kernel/debug/kmemleak. Enabling this
658 feature will introduce an overhead to memory
659 allocations. See Documentation/dev-tools/kmemleak.rst for more
662 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
663 of finding leaks due to the slab objects poisoning.
665 In order to access the kmemleak file, debugfs needs to be
666 mounted (usually at /sys/kernel/debug).
668 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
669 int "Kmemleak memory pool size"
670 depends on DEBUG_KMEMLEAK
674 Kmemleak must track all the memory allocations to avoid
675 reporting false positives. Since memory may be allocated or
676 freed before kmemleak is fully initialised, use a static pool
677 of metadata objects to track such callbacks. After kmemleak is
678 fully initialised, this memory pool acts as an emergency one
679 if slab allocations fail.
681 config DEBUG_KMEMLEAK_TEST
682 tristate "Simple test for the kernel memory leak detector"
683 depends on DEBUG_KMEMLEAK && m
685 This option enables a module that explicitly leaks memory.
689 config DEBUG_KMEMLEAK_DEFAULT_OFF
690 bool "Default kmemleak to off"
691 depends on DEBUG_KMEMLEAK
693 Say Y here to disable kmemleak by default. It can then be enabled
694 on the command line via kmemleak=on.
696 config DEBUG_KMEMLEAK_AUTO_SCAN
697 bool "Enable kmemleak auto scan thread on boot up"
699 depends on DEBUG_KMEMLEAK
701 Depending on the cpu, kmemleak scan may be cpu intensive and can
702 stall user tasks at times. This option enables/disables automatic
703 kmemleak scan at boot up.
705 Say N here to disable kmemleak auto scan thread to stop automatic
706 scanning. Disabling this option disables automatic reporting of
711 config DEBUG_STACK_USAGE
712 bool "Stack utilization instrumentation"
713 depends on DEBUG_KERNEL && !IA64
715 Enables the display of the minimum amount of free stack which each
716 task has ever had available in the sysrq-T and sysrq-P debug output.
718 This option will slow down process creation somewhat.
720 config SCHED_STACK_END_CHECK
721 bool "Detect stack corruption on calls to schedule()"
722 depends on DEBUG_KERNEL
725 This option checks for a stack overrun on calls to schedule().
726 If the stack end location is found to be over written always panic as
727 the content of the corrupted region can no longer be trusted.
728 This is to ensure no erroneous behaviour occurs which could result in
729 data corruption or a sporadic crash at a later stage once the region
730 is examined. The runtime overhead introduced is minimal.
732 config ARCH_HAS_DEBUG_VM_PGTABLE
735 An architecture should select this when it can successfully
736 build and run DEBUG_VM_PGTABLE.
740 depends on DEBUG_KERNEL
742 Enable this to turn on extended checks in the virtual-memory system
743 that may impact performance.
747 config DEBUG_VM_VMACACHE
748 bool "Debug VMA caching"
751 Enable this to turn on VMA caching debug information. Doing so
752 can cause significant overhead, so only enable it in non-production
758 bool "Debug VM red-black trees"
761 Enable VM red-black tree debugging information and extra validations.
765 config DEBUG_VM_PGFLAGS
766 bool "Debug page-flags operations"
769 Enables extra validation on page flags operations.
773 config DEBUG_VM_PGTABLE
774 bool "Debug arch page table for semantics compliance"
776 depends on ARCH_HAS_DEBUG_VM_PGTABLE
777 default y if DEBUG_VM
779 This option provides a debug method which can be used to test
780 architecture page table helper functions on various platforms in
781 verifying if they comply with expected generic MM semantics. This
782 will help architecture code in making sure that any changes or
783 new additions of these helpers still conform to expected
784 semantics of the generic MM. Platforms will have to opt in for
785 this through ARCH_HAS_DEBUG_VM_PGTABLE.
789 config ARCH_HAS_DEBUG_VIRTUAL
793 bool "Debug VM translations"
794 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
796 Enable some costly sanity checks in virtual to page code. This can
797 catch mistakes with virt_to_page() and friends.
801 config DEBUG_NOMMU_REGIONS
802 bool "Debug the global anon/private NOMMU mapping region tree"
803 depends on DEBUG_KERNEL && !MMU
805 This option causes the global tree of anonymous and private mapping
806 regions to be regularly checked for invalid topology.
808 config DEBUG_MEMORY_INIT
809 bool "Debug memory initialisation" if EXPERT
812 Enable this for additional checks during memory initialisation.
813 The sanity checks verify aspects of the VM such as the memory model
814 and other information provided by the architecture. Verbose
815 information will be printed at KERN_DEBUG loglevel depending
816 on the mminit_loglevel= command-line option.
820 config MEMORY_NOTIFIER_ERROR_INJECT
821 tristate "Memory hotplug notifier error injection module"
822 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
824 This option provides the ability to inject artificial errors to
825 memory hotplug notifier chain callbacks. It is controlled through
826 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
828 If the notifier call chain should be failed with some events
829 notified, write the error code to "actions/<notifier event>/error".
831 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
833 # cd /sys/kernel/debug/notifier-error-inject/memory
834 # echo -12 > actions/MEM_GOING_OFFLINE/error
835 # echo offline > /sys/devices/system/memory/memoryXXX/state
836 bash: echo: write error: Cannot allocate memory
838 To compile this code as a module, choose M here: the module will
839 be called memory-notifier-error-inject.
843 config DEBUG_PER_CPU_MAPS
844 bool "Debug access to per_cpu maps"
845 depends on DEBUG_KERNEL
848 Say Y to verify that the per_cpu map being accessed has
849 been set up. This adds a fair amount of code to kernel memory
850 and decreases performance.
855 bool "Highmem debugging"
856 depends on DEBUG_KERNEL && HIGHMEM
858 This option enables additional error checking for high memory
859 systems. Disable for production systems.
861 config HAVE_DEBUG_STACKOVERFLOW
864 config DEBUG_STACKOVERFLOW
865 bool "Check for stack overflows"
866 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
868 Say Y here if you want to check for overflows of kernel, IRQ
869 and exception stacks (if your architecture uses them). This
870 option will show detailed messages if free stack space drops
871 below a certain limit.
873 These kinds of bugs usually occur when call-chains in the
874 kernel get too deep, especially when interrupts are
877 Use this in cases where you see apparently random memory
878 corruption, especially if it appears in 'struct thread_info'
880 If in doubt, say "N".
882 source "lib/Kconfig.kasan"
884 endmenu # "Memory Debugging"
887 bool "Debug shared IRQ handlers"
888 depends on DEBUG_KERNEL
890 Enable this to generate a spurious interrupt just before a shared
891 interrupt handler is deregistered (generating one when registering
892 is currently disabled). Drivers need to handle this correctly. Some
893 don't and need to be caught.
895 menu "Debug Oops, Lockups and Hangs"
900 Say Y here to enable the kernel to panic when it oopses. This
901 has the same effect as setting oops=panic on the kernel command
904 This feature is useful to ensure that the kernel does not do
905 anything erroneous after an oops which could result in data
906 corruption or other issues.
910 config PANIC_ON_OOPS_VALUE
913 default 0 if !PANIC_ON_OOPS
914 default 1 if PANIC_ON_OOPS
920 Set the timeout value (in seconds) until a reboot occurs when
921 the kernel panics. If n = 0, then we wait forever. A timeout
922 value n > 0 will wait n seconds before rebooting, while a timeout
923 value n < 0 will reboot immediately.
925 config LOCKUP_DETECTOR
928 config SOFTLOCKUP_DETECTOR
929 bool "Detect Soft Lockups"
930 depends on DEBUG_KERNEL && !S390
931 select LOCKUP_DETECTOR
933 Say Y here to enable the kernel to act as a watchdog to detect
936 Softlockups are bugs that cause the kernel to loop in kernel
937 mode for more than 20 seconds, without giving other tasks a
938 chance to run. The current stack trace is displayed upon
939 detection and the system will stay locked up.
941 config BOOTPARAM_SOFTLOCKUP_PANIC
942 bool "Panic (Reboot) On Soft Lockups"
943 depends on SOFTLOCKUP_DETECTOR
945 Say Y here to enable the kernel to panic on "soft lockups",
946 which are bugs that cause the kernel to loop in kernel
947 mode for more than 20 seconds (configurable using the watchdog_thresh
948 sysctl), without giving other tasks a chance to run.
950 The panic can be used in combination with panic_timeout,
951 to cause the system to reboot automatically after a
952 lockup has been detected. This feature is useful for
953 high-availability systems that have uptime guarantees and
954 where a lockup must be resolved ASAP.
958 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
960 depends on SOFTLOCKUP_DETECTOR
962 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
963 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
965 config HARDLOCKUP_DETECTOR_PERF
967 select SOFTLOCKUP_DETECTOR
970 # Enables a timestamp based low pass filter to compensate for perf based
971 # hard lockup detection which runs too fast due to turbo modes.
973 config HARDLOCKUP_CHECK_TIMESTAMP
977 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
978 # lockup detector rather than the perf based detector.
980 config HARDLOCKUP_DETECTOR
981 bool "Detect Hard Lockups"
982 depends on DEBUG_KERNEL && !S390
983 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
984 select LOCKUP_DETECTOR
985 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
987 Say Y here to enable the kernel to act as a watchdog to detect
990 Hardlockups are bugs that cause the CPU to loop in kernel mode
991 for more than 10 seconds, without letting other interrupts have a
992 chance to run. The current stack trace is displayed upon detection
993 and the system will stay locked up.
995 config BOOTPARAM_HARDLOCKUP_PANIC
996 bool "Panic (Reboot) On Hard Lockups"
997 depends on HARDLOCKUP_DETECTOR
999 Say Y here to enable the kernel to panic on "hard lockups",
1000 which are bugs that cause the kernel to loop in kernel
1001 mode with interrupts disabled for more than 10 seconds (configurable
1002 using the watchdog_thresh sysctl).
1006 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
1008 depends on HARDLOCKUP_DETECTOR
1010 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
1011 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
1013 config DETECT_HUNG_TASK
1014 bool "Detect Hung Tasks"
1015 depends on DEBUG_KERNEL
1016 default SOFTLOCKUP_DETECTOR
1018 Say Y here to enable the kernel to detect "hung tasks",
1019 which are bugs that cause the task to be stuck in
1020 uninterruptible "D" state indefinitely.
1022 When a hung task is detected, the kernel will print the
1023 current stack trace (which you should report), but the
1024 task will stay in uninterruptible state. If lockdep is
1025 enabled then all held locks will also be reported. This
1026 feature has negligible overhead.
1028 config DEFAULT_HUNG_TASK_TIMEOUT
1029 int "Default timeout for hung task detection (in seconds)"
1030 depends on DETECT_HUNG_TASK
1033 This option controls the default timeout (in seconds) used
1034 to determine when a task has become non-responsive and should
1037 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1038 sysctl or by writing a value to
1039 /proc/sys/kernel/hung_task_timeout_secs.
1041 A timeout of 0 disables the check. The default is two minutes.
1042 Keeping the default should be fine in most cases.
1044 config BOOTPARAM_HUNG_TASK_PANIC
1045 bool "Panic (Reboot) On Hung Tasks"
1046 depends on DETECT_HUNG_TASK
1048 Say Y here to enable the kernel to panic on "hung tasks",
1049 which are bugs that cause the kernel to leave a task stuck
1050 in uninterruptible "D" state.
1052 The panic can be used in combination with panic_timeout,
1053 to cause the system to reboot automatically after a
1054 hung task has been detected. This feature is useful for
1055 high-availability systems that have uptime guarantees and
1056 where a hung tasks must be resolved ASAP.
1060 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
1062 depends on DETECT_HUNG_TASK
1064 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
1065 default 1 if BOOTPARAM_HUNG_TASK_PANIC
1068 bool "Detect Workqueue Stalls"
1069 depends on DEBUG_KERNEL
1071 Say Y here to enable stall detection on workqueues. If a
1072 worker pool doesn't make forward progress on a pending work
1073 item for over a given amount of time, 30s by default, a
1074 warning message is printed along with dump of workqueue
1075 state. This can be configured through kernel parameter
1076 "workqueue.watchdog_thresh" and its sysfs counterpart.
1079 tristate "Test module to generate lockups"
1082 This builds the "test_lockup" module that helps to make sure
1083 that watchdogs and lockup detectors are working properly.
1085 Depending on module parameters it could emulate soft or hard
1086 lockup, "hung task", or locking arbitrary lock for a long time.
1087 Also it could generate series of lockups with cooling-down periods.
1091 endmenu # "Debug lockups and hangs"
1093 menu "Scheduler Debugging"
1096 bool "Collect scheduler debugging info"
1097 depends on DEBUG_KERNEL && PROC_FS
1100 If you say Y here, the /proc/sched_debug file will be provided
1101 that can help debug the scheduler. The runtime overhead of this
1109 bool "Collect scheduler statistics"
1110 depends on DEBUG_KERNEL && PROC_FS
1113 If you say Y here, additional code will be inserted into the
1114 scheduler and related routines to collect statistics about
1115 scheduler behavior and provide them in /proc/schedstat. These
1116 stats may be useful for both tuning and debugging the scheduler
1117 If you aren't debugging the scheduler or trying to tune a specific
1118 application, you can say N to avoid the very slight overhead
1123 config DEBUG_TIMEKEEPING
1124 bool "Enable extra timekeeping sanity checking"
1126 This option will enable additional timekeeping sanity checks
1127 which may be helpful when diagnosing issues where timekeeping
1128 problems are suspected.
1130 This may include checks in the timekeeping hotpaths, so this
1131 option may have a (very small) performance impact to some
1136 config DEBUG_PREEMPT
1137 bool "Debug preemptible kernel"
1138 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1140 If you say Y here then the kernel will use a debug variant of the
1141 commonly used smp_processor_id() function and will print warnings
1142 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1143 will detect preemption count underflows.
1145 This option has potential to introduce high runtime overhead,
1146 depending on workload as it triggers debugging routines for each
1147 this_cpu operation. It should only be used for debugging purposes.
1149 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1151 config LOCK_DEBUGGING_SUPPORT
1153 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1156 config PROVE_LOCKING
1157 bool "Lock debugging: prove locking correctness"
1158 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1160 select DEBUG_SPINLOCK
1161 select DEBUG_MUTEXES
1162 select DEBUG_RT_MUTEXES if RT_MUTEXES
1164 select DEBUG_WW_MUTEX_SLOWPATH
1165 select DEBUG_LOCK_ALLOC
1166 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1167 select TRACE_IRQFLAGS
1170 This feature enables the kernel to prove that all locking
1171 that occurs in the kernel runtime is mathematically
1172 correct: that under no circumstance could an arbitrary (and
1173 not yet triggered) combination of observed locking
1174 sequences (on an arbitrary number of CPUs, running an
1175 arbitrary number of tasks and interrupt contexts) cause a
1178 In short, this feature enables the kernel to report locking
1179 related deadlocks before they actually occur.
1181 The proof does not depend on how hard and complex a
1182 deadlock scenario would be to trigger: how many
1183 participant CPUs, tasks and irq-contexts would be needed
1184 for it to trigger. The proof also does not depend on
1185 timing: if a race and a resulting deadlock is possible
1186 theoretically (no matter how unlikely the race scenario
1187 is), it will be proven so and will immediately be
1188 reported by the kernel (once the event is observed that
1189 makes the deadlock theoretically possible).
1191 If a deadlock is impossible (i.e. the locking rules, as
1192 observed by the kernel, are mathematically correct), the
1193 kernel reports nothing.
1195 NOTE: this feature can also be enabled for rwlocks, mutexes
1196 and rwsems - in which case all dependencies between these
1197 different locking variants are observed and mapped too, and
1198 the proof of observed correctness is also maintained for an
1199 arbitrary combination of these separate locking variants.
1201 For more details, see Documentation/locking/lockdep-design.rst.
1203 config PROVE_RAW_LOCK_NESTING
1204 bool "Enable raw_spinlock - spinlock nesting checks"
1205 depends on PROVE_LOCKING
1208 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1209 that the lock nesting rules for PREEMPT_RT enabled kernels are
1212 NOTE: There are known nesting problems. So if you enable this
1213 option expect lockdep splats until these problems have been fully
1214 addressed which is work in progress. This config switch allows to
1215 identify and analyze these problems. It will be removed and the
1216 check permanentely enabled once the main issues have been fixed.
1218 If unsure, select N.
1221 bool "Lock usage statistics"
1222 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1224 select DEBUG_SPINLOCK
1225 select DEBUG_MUTEXES
1226 select DEBUG_RT_MUTEXES if RT_MUTEXES
1227 select DEBUG_LOCK_ALLOC
1230 This feature enables tracking lock contention points
1232 For more details, see Documentation/locking/lockstat.rst
1234 This also enables lock events required by "perf lock",
1236 If you want to use "perf lock", you also need to turn on
1237 CONFIG_EVENT_TRACING.
1239 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1240 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1242 config DEBUG_RT_MUTEXES
1243 bool "RT Mutex debugging, deadlock detection"
1244 depends on DEBUG_KERNEL && RT_MUTEXES
1246 This allows rt mutex semantics violations and rt mutex related
1247 deadlocks (lockups) to be detected and reported automatically.
1249 config DEBUG_SPINLOCK
1250 bool "Spinlock and rw-lock debugging: basic checks"
1251 depends on DEBUG_KERNEL
1252 select UNINLINE_SPIN_UNLOCK
1254 Say Y here and build SMP to catch missing spinlock initialization
1255 and certain other kinds of spinlock errors commonly made. This is
1256 best used in conjunction with the NMI watchdog so that spinlock
1257 deadlocks are also debuggable.
1259 config DEBUG_MUTEXES
1260 bool "Mutex debugging: basic checks"
1261 depends on DEBUG_KERNEL
1263 This feature allows mutex semantics violations to be detected and
1266 config DEBUG_WW_MUTEX_SLOWPATH
1267 bool "Wait/wound mutex debugging: Slowpath testing"
1268 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1269 select DEBUG_LOCK_ALLOC
1270 select DEBUG_SPINLOCK
1271 select DEBUG_MUTEXES
1273 This feature enables slowpath testing for w/w mutex users by
1274 injecting additional -EDEADLK wound/backoff cases. Together with
1275 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1276 will test all possible w/w mutex interface abuse with the
1277 exception of simply not acquiring all the required locks.
1278 Note that this feature can introduce significant overhead, so
1279 it really should not be enabled in a production or distro kernel,
1280 even a debug kernel. If you are a driver writer, enable it. If
1281 you are a distro, do not.
1284 bool "RW Semaphore debugging: basic checks"
1285 depends on DEBUG_KERNEL
1287 This debugging feature allows mismatched rw semaphore locks
1288 and unlocks to be detected and reported.
1290 config DEBUG_LOCK_ALLOC
1291 bool "Lock debugging: detect incorrect freeing of live locks"
1292 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1293 select DEBUG_SPINLOCK
1294 select DEBUG_MUTEXES
1295 select DEBUG_RT_MUTEXES if RT_MUTEXES
1298 This feature will check whether any held lock (spinlock, rwlock,
1299 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1300 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1301 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1302 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1303 held during task exit.
1307 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1312 config LOCKDEP_SMALL
1316 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1317 depends on LOCKDEP && !LOCKDEP_SMALL
1321 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1323 config LOCKDEP_CHAINS_BITS
1324 int "Bitsize for MAX_LOCKDEP_CHAINS"
1325 depends on LOCKDEP && !LOCKDEP_SMALL
1329 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1331 config LOCKDEP_STACK_TRACE_BITS
1332 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1333 depends on LOCKDEP && !LOCKDEP_SMALL
1337 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1339 config LOCKDEP_STACK_TRACE_HASH_BITS
1340 int "Bitsize for STACK_TRACE_HASH_SIZE"
1341 depends on LOCKDEP && !LOCKDEP_SMALL
1345 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1347 config LOCKDEP_CIRCULAR_QUEUE_BITS
1348 int "Bitsize for elements in circular_queue struct"
1353 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1355 config DEBUG_LOCKDEP
1356 bool "Lock dependency engine debugging"
1357 depends on DEBUG_KERNEL && LOCKDEP
1359 If you say Y here, the lock dependency engine will do
1360 additional runtime checks to debug itself, at the price
1361 of more runtime overhead.
1363 config DEBUG_ATOMIC_SLEEP
1364 bool "Sleep inside atomic section checking"
1365 select PREEMPT_COUNT
1366 depends on DEBUG_KERNEL
1367 depends on !ARCH_NO_PREEMPT
1369 If you say Y here, various routines which may sleep will become very
1370 noisy if they are called inside atomic sections: when a spinlock is
1371 held, inside an rcu read side critical section, inside preempt disabled
1372 sections, inside an interrupt, etc...
1374 config DEBUG_LOCKING_API_SELFTESTS
1375 bool "Locking API boot-time self-tests"
1376 depends on DEBUG_KERNEL
1378 Say Y here if you want the kernel to run a short self-test during
1379 bootup. The self-test checks whether common types of locking bugs
1380 are detected by debugging mechanisms or not. (if you disable
1381 lock debugging then those bugs wont be detected of course.)
1382 The following locking APIs are covered: spinlocks, rwlocks,
1385 config LOCK_TORTURE_TEST
1386 tristate "torture tests for locking"
1387 depends on DEBUG_KERNEL
1390 This option provides a kernel module that runs torture tests
1391 on kernel locking primitives. The kernel module may be built
1392 after the fact on the running kernel to be tested, if desired.
1394 Say Y here if you want kernel locking-primitive torture tests
1395 to be built into the kernel.
1396 Say M if you want these torture tests to build as a module.
1397 Say N if you are unsure.
1399 config WW_MUTEX_SELFTEST
1400 tristate "Wait/wound mutex selftests"
1402 This option provides a kernel module that runs tests on the
1403 on the struct ww_mutex locking API.
1405 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1406 with this test harness.
1408 Say M if you want these self tests to build as a module.
1409 Say N if you are unsure.
1411 config SCF_TORTURE_TEST
1412 tristate "torture tests for smp_call_function*()"
1413 depends on DEBUG_KERNEL
1416 This option provides a kernel module that runs torture tests
1417 on the smp_call_function() family of primitives. The kernel
1418 module may be built after the fact on the running kernel to
1419 be tested, if desired.
1421 config CSD_LOCK_WAIT_DEBUG
1422 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1423 depends on DEBUG_KERNEL
1427 This option enables debug prints when CPUs are slow to respond
1428 to the smp_call_function*() IPI wrappers. These debug prints
1429 include the IPI handler function currently executing (if any)
1430 and relevant stack traces.
1432 endmenu # lock debugging
1434 config TRACE_IRQFLAGS
1435 depends on TRACE_IRQFLAGS_SUPPORT
1438 Enables hooks to interrupt enabling and disabling for
1439 either tracing or lock debugging.
1441 config TRACE_IRQFLAGS_NMI
1443 depends on TRACE_IRQFLAGS
1444 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1447 bool "Stack backtrace support"
1448 depends on STACKTRACE_SUPPORT
1450 This option causes the kernel to create a /proc/pid/stack for
1451 every process, showing its current stack trace.
1452 It is also used by various kernel debugging features that require
1453 stack trace generation.
1455 config WARN_ALL_UNSEEDED_RANDOM
1456 bool "Warn for all uses of unseeded randomness"
1459 Some parts of the kernel contain bugs relating to their use of
1460 cryptographically secure random numbers before it's actually possible
1461 to generate those numbers securely. This setting ensures that these
1462 flaws don't go unnoticed, by enabling a message, should this ever
1463 occur. This will allow people with obscure setups to know when things
1464 are going wrong, so that they might contact developers about fixing
1467 Unfortunately, on some models of some architectures getting
1468 a fully seeded CRNG is extremely difficult, and so this can
1469 result in dmesg getting spammed for a surprisingly long
1470 time. This is really bad from a security perspective, and
1471 so architecture maintainers really need to do what they can
1472 to get the CRNG seeded sooner after the system is booted.
1473 However, since users cannot do anything actionable to
1474 address this, by default this option is disabled.
1476 Say Y here if you want to receive warnings for all uses of
1477 unseeded randomness. This will be of use primarily for
1478 those developers interested in improving the security of
1479 Linux kernels running on their architecture (or
1482 config DEBUG_KOBJECT
1483 bool "kobject debugging"
1484 depends on DEBUG_KERNEL
1486 If you say Y here, some extra kobject debugging messages will be sent
1489 config DEBUG_KOBJECT_RELEASE
1490 bool "kobject release debugging"
1491 depends on DEBUG_OBJECTS_TIMERS
1493 kobjects are reference counted objects. This means that their
1494 last reference count put is not predictable, and the kobject can
1495 live on past the point at which a driver decides to drop it's
1496 initial reference to the kobject gained on allocation. An
1497 example of this would be a struct device which has just been
1500 However, some buggy drivers assume that after such an operation,
1501 the memory backing the kobject can be immediately freed. This
1502 goes completely against the principles of a refcounted object.
1504 If you say Y here, the kernel will delay the release of kobjects
1505 on the last reference count to improve the visibility of this
1506 kind of kobject release bug.
1508 config HAVE_DEBUG_BUGVERBOSE
1511 menu "Debug kernel data structures"
1514 bool "Debug linked list manipulation"
1515 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1517 Enable this to turn on extended checks in the linked-list
1523 bool "Debug priority linked list manipulation"
1524 depends on DEBUG_KERNEL
1526 Enable this to turn on extended checks in the priority-ordered
1527 linked-list (plist) walking routines. This checks the entire
1528 list multiple times during each manipulation.
1533 bool "Debug SG table operations"
1534 depends on DEBUG_KERNEL
1536 Enable this to turn on checks on scatter-gather tables. This can
1537 help find problems with drivers that do not properly initialize
1542 config DEBUG_NOTIFIERS
1543 bool "Debug notifier call chains"
1544 depends on DEBUG_KERNEL
1546 Enable this to turn on sanity checking for notifier call chains.
1547 This is most useful for kernel developers to make sure that
1548 modules properly unregister themselves from notifier chains.
1549 This is a relatively cheap check but if you care about maximum
1552 config BUG_ON_DATA_CORRUPTION
1553 bool "Trigger a BUG when data corruption is detected"
1556 Select this option if the kernel should BUG when it encounters
1557 data corruption in kernel memory structures when they get checked
1564 config DEBUG_CREDENTIALS
1565 bool "Debug credential management"
1566 depends on DEBUG_KERNEL
1568 Enable this to turn on some debug checking for credential
1569 management. The additional code keeps track of the number of
1570 pointers from task_structs to any given cred struct, and checks to
1571 see that this number never exceeds the usage count of the cred
1574 Furthermore, if SELinux is enabled, this also checks that the
1575 security pointer in the cred struct is never seen to be invalid.
1579 source "kernel/rcu/Kconfig.debug"
1581 config DEBUG_WQ_FORCE_RR_CPU
1582 bool "Force round-robin CPU selection for unbound work items"
1583 depends on DEBUG_KERNEL
1586 Workqueue used to implicitly guarantee that work items queued
1587 without explicit CPU specified are put on the local CPU. This
1588 guarantee is no longer true and while local CPU is still
1589 preferred work items may be put on foreign CPUs. Kernel
1590 parameter "workqueue.debug_force_rr_cpu" is added to force
1591 round-robin CPU selection to flush out usages which depend on the
1592 now broken guarantee. This config option enables the debug
1593 feature by default. When enabled, memory and cache locality will
1596 config DEBUG_BLOCK_EXT_DEVT
1597 bool "Force extended block device numbers and spread them"
1598 depends on DEBUG_KERNEL
1602 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1603 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1604 YOU ARE DOING. Distros, please enable this and fix whatever
1607 Conventionally, block device numbers are allocated from
1608 predetermined contiguous area. However, extended block area
1609 may introduce non-contiguous block device numbers. This
1610 option forces most block device numbers to be allocated from
1611 the extended space and spreads them to discover kernel or
1612 userland code paths which assume predetermined contiguous
1613 device number allocation.
1615 Note that turning on this debug option shuffles all the
1616 device numbers for all IDE and SCSI devices including libata
1617 ones, so root partition specified using device number
1618 directly (via rdev or root=MAJ:MIN) won't work anymore.
1619 Textual device names (root=/dev/sdXn) will continue to work.
1621 Say N if you are unsure.
1623 config CPU_HOTPLUG_STATE_CONTROL
1624 bool "Enable CPU hotplug state control"
1625 depends on DEBUG_KERNEL
1626 depends on HOTPLUG_CPU
1629 Allows to write steps between "offline" and "online" to the CPUs
1630 sysfs target file so states can be stepped granular. This is a debug
1631 option for now as the hotplug machinery cannot be stopped and
1632 restarted at arbitrary points yet.
1634 Say N if your are unsure.
1637 bool "Latency measuring infrastructure"
1638 depends on DEBUG_KERNEL
1639 depends on STACKTRACE_SUPPORT
1641 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1648 Enable this option if you want to use the LatencyTOP tool
1649 to find out which userspace is blocking on what kernel operations.
1651 source "kernel/trace/Kconfig"
1653 config PROVIDE_OHCI1394_DMA_INIT
1654 bool "Remote debugging over FireWire early on boot"
1655 depends on PCI && X86
1657 If you want to debug problems which hang or crash the kernel early
1658 on boot and the crashing machine has a FireWire port, you can use
1659 this feature to remotely access the memory of the crashed machine
1660 over FireWire. This employs remote DMA as part of the OHCI1394
1661 specification which is now the standard for FireWire controllers.
1663 With remote DMA, you can monitor the printk buffer remotely using
1664 firescope and access all memory below 4GB using fireproxy from gdb.
1665 Even controlling a kernel debugger is possible using remote DMA.
1669 If ohci1394_dma=early is used as boot parameter, it will initialize
1670 all OHCI1394 controllers which are found in the PCI config space.
1672 As all changes to the FireWire bus such as enabling and disabling
1673 devices cause a bus reset and thereby disable remote DMA for all
1674 devices, be sure to have the cable plugged and FireWire enabled on
1675 the debugging host before booting the debug target for debugging.
1677 This code (~1k) is freed after boot. By then, the firewire stack
1678 in charge of the OHCI-1394 controllers should be used instead.
1680 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1682 source "samples/Kconfig"
1684 config ARCH_HAS_DEVMEM_IS_ALLOWED
1687 config STRICT_DEVMEM
1688 bool "Filter access to /dev/mem"
1689 depends on MMU && DEVMEM
1690 depends on ARCH_HAS_DEVMEM_IS_ALLOWED
1691 default y if PPC || X86 || ARM64
1693 If this option is disabled, you allow userspace (root) access to all
1694 of memory, including kernel and userspace memory. Accidental
1695 access to this is obviously disastrous, but specific access can
1696 be used by people debugging the kernel. Note that with PAT support
1697 enabled, even in this case there are restrictions on /dev/mem
1698 use due to the cache aliasing requirements.
1700 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1701 file only allows userspace access to PCI space and the BIOS code and
1702 data regions. This is sufficient for dosemu and X and all common
1707 config IO_STRICT_DEVMEM
1708 bool "Filter I/O access to /dev/mem"
1709 depends on STRICT_DEVMEM
1711 If this option is disabled, you allow userspace (root) access to all
1712 io-memory regardless of whether a driver is actively using that
1713 range. Accidental access to this is obviously disastrous, but
1714 specific access can be used by people debugging kernel drivers.
1716 If this option is switched on, the /dev/mem file only allows
1717 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1718 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1719 if the driver using a given range cannot be disabled.
1723 menu "$(SRCARCH) Debugging"
1725 source "arch/$(SRCARCH)/Kconfig.debug"
1729 menu "Kernel Testing and Coverage"
1731 source "lib/kunit/Kconfig"
1733 config NOTIFIER_ERROR_INJECTION
1734 tristate "Notifier error injection"
1735 depends on DEBUG_KERNEL
1738 This option provides the ability to inject artificial errors to
1739 specified notifier chain callbacks. It is useful to test the error
1740 handling of notifier call chain failures.
1744 config PM_NOTIFIER_ERROR_INJECT
1745 tristate "PM notifier error injection module"
1746 depends on PM && NOTIFIER_ERROR_INJECTION
1747 default m if PM_DEBUG
1749 This option provides the ability to inject artificial errors to
1750 PM notifier chain callbacks. It is controlled through debugfs
1751 interface /sys/kernel/debug/notifier-error-inject/pm
1753 If the notifier call chain should be failed with some events
1754 notified, write the error code to "actions/<notifier event>/error".
1756 Example: Inject PM suspend error (-12 = -ENOMEM)
1758 # cd /sys/kernel/debug/notifier-error-inject/pm/
1759 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1760 # echo mem > /sys/power/state
1761 bash: echo: write error: Cannot allocate memory
1763 To compile this code as a module, choose M here: the module will
1764 be called pm-notifier-error-inject.
1768 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1769 tristate "OF reconfig notifier error injection module"
1770 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1772 This option provides the ability to inject artificial errors to
1773 OF reconfig notifier chain callbacks. It is controlled
1774 through debugfs interface under
1775 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1777 If the notifier call chain should be failed with some events
1778 notified, write the error code to "actions/<notifier event>/error".
1780 To compile this code as a module, choose M here: the module will
1781 be called of-reconfig-notifier-error-inject.
1785 config NETDEV_NOTIFIER_ERROR_INJECT
1786 tristate "Netdev notifier error injection module"
1787 depends on NET && NOTIFIER_ERROR_INJECTION
1789 This option provides the ability to inject artificial errors to
1790 netdevice notifier chain callbacks. It is controlled through debugfs
1791 interface /sys/kernel/debug/notifier-error-inject/netdev
1793 If the notifier call chain should be failed with some events
1794 notified, write the error code to "actions/<notifier event>/error".
1796 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1798 # cd /sys/kernel/debug/notifier-error-inject/netdev
1799 # echo -22 > actions/NETDEV_CHANGEMTU/error
1800 # ip link set eth0 mtu 1024
1801 RTNETLINK answers: Invalid argument
1803 To compile this code as a module, choose M here: the module will
1804 be called netdev-notifier-error-inject.
1808 config FUNCTION_ERROR_INJECTION
1809 bool "Fault-injections of functions"
1810 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1812 Add fault injections into various functions that are annotated with
1813 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
1814 value of theses functions. This is useful to test error paths of code.
1818 config FAULT_INJECTION
1819 bool "Fault-injection framework"
1820 depends on DEBUG_KERNEL
1822 Provide fault-injection framework.
1823 For more details, see Documentation/fault-injection/.
1826 bool "Fault-injection capability for kmalloc"
1827 depends on FAULT_INJECTION
1828 depends on SLAB || SLUB
1830 Provide fault-injection capability for kmalloc.
1832 config FAIL_PAGE_ALLOC
1833 bool "Fault-injection capability for alloc_pages()"
1834 depends on FAULT_INJECTION
1836 Provide fault-injection capability for alloc_pages().
1838 config FAULT_INJECTION_USERCOPY
1839 bool "Fault injection capability for usercopy functions"
1840 depends on FAULT_INJECTION
1842 Provides fault-injection capability to inject failures
1843 in usercopy functions (copy_from_user(), get_user(), ...).
1845 config FAIL_MAKE_REQUEST
1846 bool "Fault-injection capability for disk IO"
1847 depends on FAULT_INJECTION && BLOCK
1849 Provide fault-injection capability for disk IO.
1851 config FAIL_IO_TIMEOUT
1852 bool "Fault-injection capability for faking disk interrupts"
1853 depends on FAULT_INJECTION && BLOCK
1855 Provide fault-injection capability on end IO handling. This
1856 will make the block layer "forget" an interrupt as configured,
1857 thus exercising the error handling.
1859 Only works with drivers that use the generic timeout handling,
1860 for others it wont do anything.
1863 bool "Fault-injection capability for futexes"
1865 depends on FAULT_INJECTION && FUTEX
1867 Provide fault-injection capability for futexes.
1869 config FAULT_INJECTION_DEBUG_FS
1870 bool "Debugfs entries for fault-injection capabilities"
1871 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1873 Enable configuration of fault-injection capabilities via debugfs.
1875 config FAIL_FUNCTION
1876 bool "Fault-injection capability for functions"
1877 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1879 Provide function-based fault-injection capability.
1880 This will allow you to override a specific function with a return
1881 with given return value. As a result, function caller will see
1882 an error value and have to handle it. This is useful to test the
1883 error handling in various subsystems.
1885 config FAIL_MMC_REQUEST
1886 bool "Fault-injection capability for MMC IO"
1887 depends on FAULT_INJECTION_DEBUG_FS && MMC
1889 Provide fault-injection capability for MMC IO.
1890 This will make the mmc core return data errors. This is
1891 useful to test the error handling in the mmc block device
1892 and to test how the mmc host driver handles retries from
1895 config FAULT_INJECTION_STACKTRACE_FILTER
1896 bool "stacktrace filter for fault-injection capabilities"
1897 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1900 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1902 Provide stacktrace filter for fault-injection capabilities
1904 config ARCH_HAS_KCOV
1907 An architecture should select this when it can successfully
1908 build and run with CONFIG_KCOV. This typically requires
1909 disabling instrumentation for some early boot code.
1911 config CC_HAS_SANCOV_TRACE_PC
1912 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1916 bool "Code coverage for fuzzing"
1917 depends on ARCH_HAS_KCOV
1918 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1920 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1922 KCOV exposes kernel code coverage information in a form suitable
1923 for coverage-guided fuzzing (randomized testing).
1925 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1926 different machines and across reboots. If you need stable PC values,
1927 disable RANDOMIZE_BASE.
1929 For more details, see Documentation/dev-tools/kcov.rst.
1931 config KCOV_ENABLE_COMPARISONS
1932 bool "Enable comparison operands collection by KCOV"
1934 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
1936 KCOV also exposes operands of every comparison in the instrumented
1937 code along with operand sizes and PCs of the comparison instructions.
1938 These operands can be used by fuzzing engines to improve the quality
1939 of fuzzing coverage.
1941 config KCOV_INSTRUMENT_ALL
1942 bool "Instrument all code by default"
1946 If you are doing generic system call fuzzing (like e.g. syzkaller),
1947 then you will want to instrument the whole kernel and you should
1948 say y here. If you are doing more targeted fuzzing (like e.g.
1949 filesystem fuzzing with AFL) then you will want to enable coverage
1950 for more specific subsets of files, and should say n here.
1952 config KCOV_IRQ_AREA_SIZE
1953 hex "Size of interrupt coverage collection area in words"
1957 KCOV uses preallocated per-cpu areas to collect coverage from
1958 soft interrupts. This specifies the size of those areas in the
1959 number of unsigned long words.
1961 menuconfig RUNTIME_TESTING_MENU
1962 bool "Runtime Testing"
1965 if RUNTIME_TESTING_MENU
1968 tristate "Linux Kernel Dump Test Tool Module"
1971 This module enables testing of the different dumping mechanisms by
1972 inducing system failures at predefined crash points.
1973 If you don't need it: say N
1974 Choose M here to compile this code as a module. The module will be
1977 Documentation on how to use the module can be found in
1978 Documentation/fault-injection/provoke-crashes.rst
1980 config TEST_LIST_SORT
1981 tristate "Linked list sorting test"
1982 depends on DEBUG_KERNEL || m
1984 Enable this to turn on 'list_sort()' function test. This test is
1985 executed only once during system boot (so affects only boot time),
1986 or at module load time.
1990 config TEST_MIN_HEAP
1991 tristate "Min heap test"
1992 depends on DEBUG_KERNEL || m
1994 Enable this to turn on min heap function tests. This test is
1995 executed only once during system boot (so affects only boot time),
1996 or at module load time.
2001 tristate "Array-based sort test"
2002 depends on DEBUG_KERNEL || m
2004 This option enables the self-test function of 'sort()' at boot,
2005 or at module load time.
2009 config KPROBES_SANITY_TEST
2010 bool "Kprobes sanity tests"
2011 depends on DEBUG_KERNEL
2014 This option provides for testing basic kprobes functionality on
2015 boot. Samples of kprobe and kretprobe are inserted and
2016 verified for functionality.
2018 Say N if you are unsure.
2020 config BACKTRACE_SELF_TEST
2021 tristate "Self test for the backtrace code"
2022 depends on DEBUG_KERNEL
2024 This option provides a kernel module that can be used to test
2025 the kernel stack backtrace code. This option is not useful
2026 for distributions or general kernels, but only for kernel
2027 developers working on architecture code.
2029 Note that if you want to also test saved backtraces, you will
2030 have to enable STACKTRACE as well.
2032 Say N if you are unsure.
2035 tristate "Red-Black tree test"
2036 depends on DEBUG_KERNEL
2038 A benchmark measuring the performance of the rbtree library.
2039 Also includes rbtree invariant checks.
2041 config REED_SOLOMON_TEST
2042 tristate "Reed-Solomon library test"
2043 depends on DEBUG_KERNEL || m
2045 select REED_SOLOMON_ENC16
2046 select REED_SOLOMON_DEC16
2048 This option enables the self-test function of rslib at boot,
2049 or at module load time.
2053 config INTERVAL_TREE_TEST
2054 tristate "Interval tree test"
2055 depends on DEBUG_KERNEL
2056 select INTERVAL_TREE
2058 A benchmark measuring the performance of the interval tree library
2061 tristate "Per cpu operations test"
2062 depends on m && DEBUG_KERNEL
2064 Enable this option to build test module which validates per-cpu
2069 config ATOMIC64_SELFTEST
2070 tristate "Perform an atomic64_t self-test"
2072 Enable this option to test the atomic64_t functions at boot or
2073 at module load time.
2077 config ASYNC_RAID6_TEST
2078 tristate "Self test for hardware accelerated raid6 recovery"
2079 depends on ASYNC_RAID6_RECOV
2082 This is a one-shot self test that permutes through the
2083 recovery of all the possible two disk failure scenarios for a
2084 N-disk array. Recovery is performed with the asynchronous
2085 raid6 recovery routines, and will optionally use an offload
2086 engine if one is available.
2091 tristate "Test functions located in the hexdump module at runtime"
2093 config TEST_STRING_HELPERS
2094 tristate "Test functions located in the string_helpers module at runtime"
2097 tristate "Test strscpy*() family of functions at runtime"
2100 tristate "Test kstrto*() family of functions at runtime"
2103 tristate "Test printf() family of functions at runtime"
2106 tristate "Test bitmap_*() family of functions at runtime"
2108 Enable this option to test the bitmap functions at boot.
2113 tristate "Test functions located in the uuid module at runtime"
2116 tristate "Test the XArray code at runtime"
2118 config TEST_OVERFLOW
2119 tristate "Test check_*_overflow() functions at runtime"
2121 config TEST_RHASHTABLE
2122 tristate "Perform selftest on resizable hash table"
2124 Enable this option to test the rhashtable functions at boot.
2129 tristate "Perform selftest on hash functions"
2131 Enable this option to test the kernel's integer (<linux/hash.h>),
2132 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
2133 hash functions on boot (or module load).
2135 This is intended to help people writing architecture-specific
2136 optimized versions. If unsure, say N.
2139 tristate "Perform selftest on IDA functions"
2142 tristate "Perform selftest on priority array manager"
2145 Enable this option to test priority array manager on boot
2150 config TEST_IRQ_TIMINGS
2151 bool "IRQ timings selftest"
2152 depends on IRQ_TIMINGS
2154 Enable this option to test the irq timings code on boot.
2159 tristate "Test module loading with 'hello world' module"
2162 This builds the "test_module" module that emits "Hello, world"
2163 on printk when loaded. It is designed to be used for basic
2164 evaluation of the module loading subsystem (for example when
2165 validating module verification). It lacks any extra dependencies,
2166 and will not normally be loaded by the system unless explicitly
2172 tristate "Test module for compilation of bitops operations"
2175 This builds the "test_bitops" module that is much like the
2176 TEST_LKM module except that it does a basic exercise of the
2177 set/clear_bit macros and get_count_order/long to make sure there are
2178 no compiler warnings from C=1 sparse checker or -Wextra
2179 compilations. It has no dependencies and doesn't run or load unless
2180 explicitly requested by name. for example: modprobe test_bitops.
2185 tristate "Test module for stress/performance analysis of vmalloc allocator"
2190 This builds the "test_vmalloc" module that should be used for
2191 stress and performance analysis. So, any new change for vmalloc
2192 subsystem can be evaluated from performance and stability point
2197 config TEST_USER_COPY
2198 tristate "Test user/kernel boundary protections"
2201 This builds the "test_user_copy" module that runs sanity checks
2202 on the copy_to/from_user infrastructure, making sure basic
2203 user/kernel boundary testing is working. If it fails to load,
2204 a regression has been detected in the user/kernel memory boundary
2210 tristate "Test BPF filter functionality"
2213 This builds the "test_bpf" module that runs various test vectors
2214 against the BPF interpreter or BPF JIT compiler depending on the
2215 current setting. This is in particular useful for BPF JIT compiler
2216 development, but also to run regression tests against changes in
2217 the interpreter code. It also enables test stubs for eBPF maps and
2218 verifier used by user space verifier testsuite.
2222 config TEST_BLACKHOLE_DEV
2223 tristate "Test blackhole netdev functionality"
2226 This builds the "test_blackhole_dev" module that validates the
2227 data path through this blackhole netdev.
2231 config FIND_BIT_BENCHMARK
2232 tristate "Test find_bit functions"
2234 This builds the "test_find_bit" module that measure find_*_bit()
2235 functions performance.
2239 config TEST_FIRMWARE
2240 tristate "Test firmware loading via userspace interface"
2241 depends on FW_LOADER
2243 This builds the "test_firmware" module that creates a userspace
2244 interface for testing firmware loading. This can be used to
2245 control the triggering of firmware loading without needing an
2246 actual firmware-using device. The contents can be rechecked by
2252 tristate "sysctl test driver"
2253 depends on PROC_SYSCTL
2255 This builds the "test_sysctl" module. This driver enables to test the
2256 proc sysctl interfaces available to drivers safely without affecting
2257 production knobs which might alter system functionality.
2261 config BITFIELD_KUNIT
2262 tristate "KUnit test bitfield functions at runtime"
2265 Enable this option to test the bitfield functions at boot.
2267 KUnit tests run during boot and output the results to the debug log
2268 in TAP format (http://testanything.org/). Only useful for kernel devs
2269 running the KUnit test harness, and not intended for inclusion into a
2272 For more information on KUnit and unit tests in general please refer
2273 to the KUnit documentation in Documentation/dev-tools/kunit/.
2277 config SYSCTL_KUNIT_TEST
2278 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2280 default KUNIT_ALL_TESTS
2282 This builds the proc sysctl unit test, which runs on boot.
2283 Tests the API contract and implementation correctness of sysctl.
2284 For more information on KUnit and unit tests in general please refer
2285 to the KUnit documentation in Documentation/dev-tools/kunit/.
2289 config LIST_KUNIT_TEST
2290 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2292 default KUNIT_ALL_TESTS
2294 This builds the linked list KUnit test suite.
2295 It tests that the API and basic functionality of the list_head type
2296 and associated macros.
2298 KUnit tests run during boot and output the results to the debug log
2299 in TAP format (https://testanything.org/). Only useful for kernel devs
2300 running the KUnit test harness, and not intended for inclusion into a
2303 For more information on KUnit and unit tests in general please refer
2304 to the KUnit documentation in Documentation/dev-tools/kunit/.
2308 config LINEAR_RANGES_TEST
2309 tristate "KUnit test for linear_ranges"
2311 select LINEAR_RANGES
2313 This builds the linear_ranges unit test, which runs on boot.
2314 Tests the linear_ranges logic correctness.
2315 For more information on KUnit and unit tests in general please refer
2316 to the KUnit documentation in Documentation/dev-tools/kunit/.
2321 tristate "KUnit test for bits.h"
2324 This builds the bits unit test.
2325 Tests the logic of macros defined in bits.h.
2326 For more information on KUnit and unit tests in general please refer
2327 to the KUnit documentation in Documentation/dev-tools/kunit/.
2332 tristate "udelay test driver"
2334 This builds the "udelay_test" module that helps to make sure
2335 that udelay() is working properly.
2339 config TEST_STATIC_KEYS
2340 tristate "Test static keys"
2343 Test the static key interfaces.
2348 tristate "kmod stress tester"
2350 depends on NETDEVICES && NET_CORE && INET # for TUN
2357 Test the kernel's module loading mechanism: kmod. kmod implements
2358 support to load modules using the Linux kernel's usermode helper.
2359 This test provides a series of tests against kmod.
2361 Although technically you can either build test_kmod as a module or
2362 into the kernel we disallow building it into the kernel since
2363 it stress tests request_module() and this will very likely cause
2364 some issues by taking over precious threads available from other
2365 module load requests, ultimately this could be fatal.
2369 tools/testing/selftests/kmod/kmod.sh --help
2373 config TEST_DEBUG_VIRTUAL
2374 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2375 depends on DEBUG_VIRTUAL
2377 Test the kernel's ability to detect incorrect calls to
2378 virt_to_phys() done against the non-linear part of the
2379 kernel's virtual address map.
2383 config TEST_MEMCAT_P
2384 tristate "Test memcat_p() helper function"
2386 Test the memcat_p() helper for correctly merging two
2387 pointer arrays together.
2391 config TEST_LIVEPATCH
2392 tristate "Test livepatching"
2394 depends on DYNAMIC_DEBUG
2395 depends on LIVEPATCH
2398 Test kernel livepatching features for correctness. The tests will
2399 load test modules that will be livepatched in various scenarios.
2401 To run all the livepatching tests:
2403 make -C tools/testing/selftests TARGETS=livepatch run_tests
2405 Alternatively, individual tests may be invoked:
2407 tools/testing/selftests/livepatch/test-callbacks.sh
2408 tools/testing/selftests/livepatch/test-livepatch.sh
2409 tools/testing/selftests/livepatch/test-shadow-vars.sh
2414 tristate "Perform selftest on object aggreration manager"
2418 Enable this option to test object aggregation manager on boot
2422 config TEST_STACKINIT
2423 tristate "Test level of stack variable initialization"
2425 Test if the kernel is zero-initializing stack variables and
2426 padding. Coverage is controlled by compiler flags,
2427 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2428 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2433 tristate "Test heap/page initialization"
2435 Test if the kernel is zero-initializing heap and page allocations.
2436 This can be useful to test init_on_alloc and init_on_free features.
2441 tristate "Test HMM (Heterogeneous Memory Management)"
2442 depends on TRANSPARENT_HUGEPAGE
2443 depends on DEVICE_PRIVATE
2447 This is a pseudo device driver solely for testing HMM.
2448 Say M here if you want to build the HMM test module.
2449 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2453 config TEST_FREE_PAGES
2454 tristate "Test freeing pages"
2456 Test that a memory leak does not occur due to a race between
2457 freeing a block of pages and a speculative page reference.
2458 Loading this module is safe if your kernel has the bug fixed.
2459 If the bug is not fixed, it will leak gigabytes of memory and
2460 probably OOM your system.
2463 tristate "Test floating point operations in kernel space"
2464 depends on X86 && !KCOV_INSTRUMENT_ALL
2466 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2467 which will trigger a sequence of floating point operations. This is used
2468 for self-testing floating point control register setting in
2473 endif # RUNTIME_TESTING_MENU
2478 This option adds a kernel parameter 'memtest', which allows memtest
2480 memtest=0, mean disabled; -- default
2481 memtest=1, mean do 1 test pattern;
2483 memtest=17, mean do 17 test patterns.
2484 If you are unsure how to answer this question, answer N.
2488 config HYPERV_TESTING
2489 bool "Microsoft Hyper-V driver testing"
2491 depends on HYPERV && DEBUG_FS
2493 Select this option to enable Hyper-V vmbus testing.
2495 endmenu # "Kernel Testing and Coverage"
2497 source "Documentation/Kconfig"
2499 endmenu # Kernel hacking