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 1280 if (!64BIT && PARISC)
302 default 1024 if (!64BIT && !PARISC)
303 default 2048 if 64BIT
305 Tell gcc to warn at build time for stack frames larger than this.
306 Setting this too low will cause a lot of warnings.
307 Setting it to 0 disables the warning.
309 config STRIP_ASM_SYMS
310 bool "Strip assembler-generated symbols during link"
313 Strip internal assembler-generated symbols during a link (symbols
314 that look like '.Lxxx') so they don't pollute the output of
315 get_wchan() and suchlike.
318 bool "Generate readable assembler code"
319 depends on DEBUG_KERNEL
321 Disable some compiler optimizations that tend to generate human unreadable
322 assembler output. This may make the kernel slightly slower, but it helps
323 to keep kernel developers who have to stare a lot at assembler listings
326 config HEADERS_INSTALL
327 bool "Install uapi headers to usr/include"
330 This option will install uapi headers (headers exported to user-space)
331 into the usr/include directory for use during the kernel build.
332 This is unneeded for building the kernel itself, but needed for some
333 user-space program samples. It is also needed by some features such
334 as uapi header sanity checks.
336 config DEBUG_SECTION_MISMATCH
337 bool "Enable full Section mismatch analysis"
339 The section mismatch analysis checks if there are illegal
340 references from one section to another section.
341 During linktime or runtime, some sections are dropped;
342 any use of code/data previously in these sections would
343 most likely result in an oops.
344 In the code, functions and variables are annotated with
345 __init,, etc. (see the full list in include/linux/init.h),
346 which results in the code/data being placed in specific sections.
347 The section mismatch analysis is always performed after a full
348 kernel build, and enabling this option causes the following
349 additional step to occur:
350 - Add the option -fno-inline-functions-called-once to gcc commands.
351 When inlining a function annotated with __init in a non-init
352 function, we would lose the section information and thus
353 the analysis would not catch the illegal reference.
354 This option tells gcc to inline less (but it does result in
357 config SECTION_MISMATCH_WARN_ONLY
358 bool "Make section mismatch errors non-fatal"
361 If you say N here, the build process will fail if there are any
362 section mismatch, instead of just throwing warnings.
366 config DEBUG_FORCE_FUNCTION_ALIGN_32B
367 bool "Force all function address 32B aligned" if EXPERT
369 There are cases that a commit from one domain changes the function
370 address alignment of other domains, and cause magic performance
371 bump (regression or improvement). Enable this option will help to
372 verify if the bump is caused by function alignment changes, while
373 it will slightly increase the kernel size and affect icache usage.
375 It is mainly for debug and performance tuning use.
378 # Select this config option from the architecture Kconfig, if it
379 # is preferred to always offer frame pointers as a config
380 # option on the architecture (regardless of KERNEL_DEBUG):
382 config ARCH_WANT_FRAME_POINTERS
386 bool "Compile the kernel with frame pointers"
387 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
388 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
390 If you say Y here the resulting kernel image will be slightly
391 larger and slower, but it gives very useful debugging information
392 in case of kernel bugs. (precise oopses/stacktraces/warnings)
394 config STACK_VALIDATION
395 bool "Compile-time stack metadata validation"
396 depends on HAVE_STACK_VALIDATION
399 Add compile-time checks to validate stack metadata, including frame
400 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
401 that runtime stack traces are more reliable.
403 This is also a prerequisite for generation of ORC unwind data, which
404 is needed for CONFIG_UNWINDER_ORC.
406 For more information, see
407 tools/objtool/Documentation/stack-validation.txt.
409 config VMLINUX_VALIDATION
411 depends on STACK_VALIDATION && DEBUG_ENTRY && !PARAVIRT
414 config DEBUG_FORCE_WEAK_PER_CPU
415 bool "Force weak per-cpu definitions"
416 depends on DEBUG_KERNEL
418 s390 and alpha require percpu variables in modules to be
419 defined weak to work around addressing range issue which
420 puts the following two restrictions on percpu variable
423 1. percpu symbols must be unique whether static or not
424 2. percpu variables can't be defined inside a function
426 To ensure that generic code follows the above rules, this
427 option forces all percpu variables to be defined as weak.
429 endmenu # "Compiler options"
431 menu "Generic Kernel Debugging Instruments"
434 bool "Magic SysRq key"
437 If you say Y here, you will have some control over the system even
438 if the system crashes for example during kernel debugging (e.g., you
439 will be able to flush the buffer cache to disk, reboot the system
440 immediately or dump some status information). This is accomplished
441 by pressing various keys while holding SysRq (Alt+PrintScreen). It
442 also works on a serial console (on PC hardware at least), if you
443 send a BREAK and then within 5 seconds a command keypress. The
444 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
445 Don't say Y unless you really know what this hack does.
447 config MAGIC_SYSRQ_DEFAULT_ENABLE
448 hex "Enable magic SysRq key functions by default"
449 depends on MAGIC_SYSRQ
452 Specifies which SysRq key functions are enabled by default.
453 This may be set to 1 or 0 to enable or disable them all, or
454 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
456 config MAGIC_SYSRQ_SERIAL
457 bool "Enable magic SysRq key over serial"
458 depends on MAGIC_SYSRQ
461 Many embedded boards have a disconnected TTL level serial which can
462 generate some garbage that can lead to spurious false sysrq detects.
463 This option allows you to decide whether you want to enable the
466 config MAGIC_SYSRQ_SERIAL_SEQUENCE
467 string "Char sequence that enables magic SysRq over serial"
468 depends on MAGIC_SYSRQ_SERIAL
471 Specifies a sequence of characters that can follow BREAK to enable
472 SysRq on a serial console.
474 If unsure, leave an empty string and the option will not be enabled.
477 bool "Debug Filesystem"
479 debugfs is a virtual file system that kernel developers use to put
480 debugging files into. Enable this option to be able to read and
481 write to these files.
483 For detailed documentation on the debugfs API, see
484 Documentation/filesystems/.
489 prompt "Debugfs default access"
491 default DEBUG_FS_ALLOW_ALL
493 This selects the default access restrictions for debugfs.
494 It can be overridden with kernel command line option
495 debugfs=[on,no-mount,off]. The restrictions apply for API access
496 and filesystem registration.
498 config DEBUG_FS_ALLOW_ALL
501 No restrictions apply. Both API and filesystem registration
502 is on. This is the normal default operation.
504 config DEBUG_FS_DISALLOW_MOUNT
505 bool "Do not register debugfs as filesystem"
507 The API is open but filesystem is not loaded. Clients can still do
508 their work and read with debug tools that do not need
511 config DEBUG_FS_ALLOW_NONE
514 Access is off. Clients get -PERM when trying to create nodes in
515 debugfs tree and debugfs is not registered as a filesystem.
516 Client can then back-off or continue without debugfs access.
520 source "lib/Kconfig.kgdb"
521 source "lib/Kconfig.ubsan"
522 source "lib/Kconfig.kcsan"
527 bool "Kernel debugging"
529 Say Y here if you are developing drivers or trying to debug and
530 identify kernel problems.
533 bool "Miscellaneous debug code"
535 depends on DEBUG_KERNEL
537 Say Y here if you need to enable miscellaneous debug code that should
538 be under a more specific debug option but isn't.
541 menu "Memory Debugging"
543 source "mm/Kconfig.debug"
546 bool "Debug object operations"
547 depends on DEBUG_KERNEL
549 If you say Y here, additional code will be inserted into the
550 kernel to track the life time of various objects and validate
551 the operations on those objects.
553 config DEBUG_OBJECTS_SELFTEST
554 bool "Debug objects selftest"
555 depends on DEBUG_OBJECTS
557 This enables the selftest of the object debug code.
559 config DEBUG_OBJECTS_FREE
560 bool "Debug objects in freed memory"
561 depends on DEBUG_OBJECTS
563 This enables checks whether a k/v free operation frees an area
564 which contains an object which has not been deactivated
565 properly. This can make kmalloc/kfree-intensive workloads
568 config DEBUG_OBJECTS_TIMERS
569 bool "Debug timer objects"
570 depends on DEBUG_OBJECTS
572 If you say Y here, additional code will be inserted into the
573 timer routines to track the life time of timer objects and
574 validate the timer operations.
576 config DEBUG_OBJECTS_WORK
577 bool "Debug work objects"
578 depends on DEBUG_OBJECTS
580 If you say Y here, additional code will be inserted into the
581 work queue routines to track the life time of work objects and
582 validate the work operations.
584 config DEBUG_OBJECTS_RCU_HEAD
585 bool "Debug RCU callbacks objects"
586 depends on DEBUG_OBJECTS
588 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
590 config DEBUG_OBJECTS_PERCPU_COUNTER
591 bool "Debug percpu counter objects"
592 depends on DEBUG_OBJECTS
594 If you say Y here, additional code will be inserted into the
595 percpu counter routines to track the life time of percpu counter
596 objects and validate the percpu counter operations.
598 config DEBUG_OBJECTS_ENABLE_DEFAULT
599 int "debug_objects bootup default value (0-1)"
602 depends on DEBUG_OBJECTS
604 Debug objects boot parameter default value
607 bool "Debug slab memory allocations"
608 depends on DEBUG_KERNEL && SLAB
610 Say Y here to have the kernel do limited verification on memory
611 allocation as well as poisoning memory on free to catch use of freed
612 memory. This can make kmalloc/kfree-intensive workloads much slower.
615 bool "SLUB debugging on by default"
616 depends on SLUB && SLUB_DEBUG
619 Boot with debugging on by default. SLUB boots by default with
620 the runtime debug capabilities switched off. Enabling this is
621 equivalent to specifying the "slub_debug" parameter on boot.
622 There is no support for more fine grained debug control like
623 possible with slub_debug=xxx. SLUB debugging may be switched
624 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
629 bool "Enable SLUB performance statistics"
630 depends on SLUB && SYSFS
632 SLUB statistics are useful to debug SLUBs allocation behavior in
633 order find ways to optimize the allocator. This should never be
634 enabled for production use since keeping statistics slows down
635 the allocator by a few percentage points. The slabinfo command
636 supports the determination of the most active slabs to figure
637 out which slabs are relevant to a particular load.
638 Try running: slabinfo -DA
640 config HAVE_DEBUG_KMEMLEAK
643 config DEBUG_KMEMLEAK
644 bool "Kernel memory leak detector"
645 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
647 select STACKTRACE if STACKTRACE_SUPPORT
651 Say Y here if you want to enable the memory leak
652 detector. The memory allocation/freeing is traced in a way
653 similar to the Boehm's conservative garbage collector, the
654 difference being that the orphan objects are not freed but
655 only shown in /sys/kernel/debug/kmemleak. Enabling this
656 feature will introduce an overhead to memory
657 allocations. See Documentation/dev-tools/kmemleak.rst for more
660 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
661 of finding leaks due to the slab objects poisoning.
663 In order to access the kmemleak file, debugfs needs to be
664 mounted (usually at /sys/kernel/debug).
666 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
667 int "Kmemleak memory pool size"
668 depends on DEBUG_KMEMLEAK
672 Kmemleak must track all the memory allocations to avoid
673 reporting false positives. Since memory may be allocated or
674 freed before kmemleak is fully initialised, use a static pool
675 of metadata objects to track such callbacks. After kmemleak is
676 fully initialised, this memory pool acts as an emergency one
677 if slab allocations fail.
679 config DEBUG_KMEMLEAK_TEST
680 tristate "Simple test for the kernel memory leak detector"
681 depends on DEBUG_KMEMLEAK && m
683 This option enables a module that explicitly leaks memory.
687 config DEBUG_KMEMLEAK_DEFAULT_OFF
688 bool "Default kmemleak to off"
689 depends on DEBUG_KMEMLEAK
691 Say Y here to disable kmemleak by default. It can then be enabled
692 on the command line via kmemleak=on.
694 config DEBUG_KMEMLEAK_AUTO_SCAN
695 bool "Enable kmemleak auto scan thread on boot up"
697 depends on DEBUG_KMEMLEAK
699 Depending on the cpu, kmemleak scan may be cpu intensive and can
700 stall user tasks at times. This option enables/disables automatic
701 kmemleak scan at boot up.
703 Say N here to disable kmemleak auto scan thread to stop automatic
704 scanning. Disabling this option disables automatic reporting of
709 config DEBUG_STACK_USAGE
710 bool "Stack utilization instrumentation"
711 depends on DEBUG_KERNEL && !IA64
713 Enables the display of the minimum amount of free stack which each
714 task has ever had available in the sysrq-T and sysrq-P debug output.
716 This option will slow down process creation somewhat.
718 config SCHED_STACK_END_CHECK
719 bool "Detect stack corruption on calls to schedule()"
720 depends on DEBUG_KERNEL
723 This option checks for a stack overrun on calls to schedule().
724 If the stack end location is found to be over written always panic as
725 the content of the corrupted region can no longer be trusted.
726 This is to ensure no erroneous behaviour occurs which could result in
727 data corruption or a sporadic crash at a later stage once the region
728 is examined. The runtime overhead introduced is minimal.
730 config ARCH_HAS_DEBUG_VM_PGTABLE
733 An architecture should select this when it can successfully
734 build and run DEBUG_VM_PGTABLE.
738 depends on DEBUG_KERNEL
740 Enable this to turn on extended checks in the virtual-memory system
741 that may impact performance.
745 config DEBUG_VM_VMACACHE
746 bool "Debug VMA caching"
749 Enable this to turn on VMA caching debug information. Doing so
750 can cause significant overhead, so only enable it in non-production
756 bool "Debug VM red-black trees"
759 Enable VM red-black tree debugging information and extra validations.
763 config DEBUG_VM_PGFLAGS
764 bool "Debug page-flags operations"
767 Enables extra validation on page flags operations.
771 config DEBUG_VM_PGTABLE
772 bool "Debug arch page table for semantics compliance"
774 depends on ARCH_HAS_DEBUG_VM_PGTABLE
775 default y if DEBUG_VM
777 This option provides a debug method which can be used to test
778 architecture page table helper functions on various platforms in
779 verifying if they comply with expected generic MM semantics. This
780 will help architecture code in making sure that any changes or
781 new additions of these helpers still conform to expected
782 semantics of the generic MM. Platforms will have to opt in for
783 this through ARCH_HAS_DEBUG_VM_PGTABLE.
787 config ARCH_HAS_DEBUG_VIRTUAL
791 bool "Debug VM translations"
792 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
794 Enable some costly sanity checks in virtual to page code. This can
795 catch mistakes with virt_to_page() and friends.
799 config DEBUG_NOMMU_REGIONS
800 bool "Debug the global anon/private NOMMU mapping region tree"
801 depends on DEBUG_KERNEL && !MMU
803 This option causes the global tree of anonymous and private mapping
804 regions to be regularly checked for invalid topology.
806 config DEBUG_MEMORY_INIT
807 bool "Debug memory initialisation" if EXPERT
810 Enable this for additional checks during memory initialisation.
811 The sanity checks verify aspects of the VM such as the memory model
812 and other information provided by the architecture. Verbose
813 information will be printed at KERN_DEBUG loglevel depending
814 on the mminit_loglevel= command-line option.
818 config MEMORY_NOTIFIER_ERROR_INJECT
819 tristate "Memory hotplug notifier error injection module"
820 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
822 This option provides the ability to inject artificial errors to
823 memory hotplug notifier chain callbacks. It is controlled through
824 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
826 If the notifier call chain should be failed with some events
827 notified, write the error code to "actions/<notifier event>/error".
829 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
831 # cd /sys/kernel/debug/notifier-error-inject/memory
832 # echo -12 > actions/MEM_GOING_OFFLINE/error
833 # echo offline > /sys/devices/system/memory/memoryXXX/state
834 bash: echo: write error: Cannot allocate memory
836 To compile this code as a module, choose M here: the module will
837 be called memory-notifier-error-inject.
841 config DEBUG_PER_CPU_MAPS
842 bool "Debug access to per_cpu maps"
843 depends on DEBUG_KERNEL
846 Say Y to verify that the per_cpu map being accessed has
847 been set up. This adds a fair amount of code to kernel memory
848 and decreases performance.
852 config DEBUG_KMAP_LOCAL
853 bool "Debug kmap_local temporary mappings"
854 depends on DEBUG_KERNEL && KMAP_LOCAL
856 This option enables additional error checking for the kmap_local
857 infrastructure. Disable for production use.
859 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
862 config DEBUG_KMAP_LOCAL_FORCE_MAP
863 bool "Enforce kmap_local temporary mappings"
864 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
866 select DEBUG_KMAP_LOCAL
868 This option enforces temporary mappings through the kmap_local
869 mechanism for non-highmem pages and on non-highmem systems.
870 Disable this for production systems!
873 bool "Highmem debugging"
874 depends on DEBUG_KERNEL && HIGHMEM
875 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
876 select DEBUG_KMAP_LOCAL
878 This option enables additional error checking for high memory
879 systems. Disable for production systems.
881 config HAVE_DEBUG_STACKOVERFLOW
884 config DEBUG_STACKOVERFLOW
885 bool "Check for stack overflows"
886 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
888 Say Y here if you want to check for overflows of kernel, IRQ
889 and exception stacks (if your architecture uses them). This
890 option will show detailed messages if free stack space drops
891 below a certain limit.
893 These kinds of bugs usually occur when call-chains in the
894 kernel get too deep, especially when interrupts are
897 Use this in cases where you see apparently random memory
898 corruption, especially if it appears in 'struct thread_info'
900 If in doubt, say "N".
902 source "lib/Kconfig.kasan"
904 endmenu # "Memory Debugging"
907 bool "Debug shared IRQ handlers"
908 depends on DEBUG_KERNEL
910 Enable this to generate a spurious interrupt just before a shared
911 interrupt handler is deregistered (generating one when registering
912 is currently disabled). Drivers need to handle this correctly. Some
913 don't and need to be caught.
915 menu "Debug Oops, Lockups and Hangs"
920 Say Y here to enable the kernel to panic when it oopses. This
921 has the same effect as setting oops=panic on the kernel command
924 This feature is useful to ensure that the kernel does not do
925 anything erroneous after an oops which could result in data
926 corruption or other issues.
930 config PANIC_ON_OOPS_VALUE
933 default 0 if !PANIC_ON_OOPS
934 default 1 if PANIC_ON_OOPS
940 Set the timeout value (in seconds) until a reboot occurs when
941 the kernel panics. If n = 0, then we wait forever. A timeout
942 value n > 0 will wait n seconds before rebooting, while a timeout
943 value n < 0 will reboot immediately.
945 config LOCKUP_DETECTOR
948 config SOFTLOCKUP_DETECTOR
949 bool "Detect Soft Lockups"
950 depends on DEBUG_KERNEL && !S390
951 select LOCKUP_DETECTOR
953 Say Y here to enable the kernel to act as a watchdog to detect
956 Softlockups are bugs that cause the kernel to loop in kernel
957 mode for more than 20 seconds, without giving other tasks a
958 chance to run. The current stack trace is displayed upon
959 detection and the system will stay locked up.
961 config BOOTPARAM_SOFTLOCKUP_PANIC
962 bool "Panic (Reboot) On Soft Lockups"
963 depends on SOFTLOCKUP_DETECTOR
965 Say Y here to enable the kernel to panic on "soft lockups",
966 which are bugs that cause the kernel to loop in kernel
967 mode for more than 20 seconds (configurable using the watchdog_thresh
968 sysctl), without giving other tasks a chance to run.
970 The panic can be used in combination with panic_timeout,
971 to cause the system to reboot automatically after a
972 lockup has been detected. This feature is useful for
973 high-availability systems that have uptime guarantees and
974 where a lockup must be resolved ASAP.
978 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
980 depends on SOFTLOCKUP_DETECTOR
982 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
983 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
985 config HARDLOCKUP_DETECTOR_PERF
987 select SOFTLOCKUP_DETECTOR
990 # Enables a timestamp based low pass filter to compensate for perf based
991 # hard lockup detection which runs too fast due to turbo modes.
993 config HARDLOCKUP_CHECK_TIMESTAMP
997 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
998 # lockup detector rather than the perf based detector.
1000 config HARDLOCKUP_DETECTOR
1001 bool "Detect Hard Lockups"
1002 depends on DEBUG_KERNEL && !S390
1003 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1004 select LOCKUP_DETECTOR
1005 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1006 select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH
1008 Say Y here to enable the kernel to act as a watchdog to detect
1011 Hardlockups are bugs that cause the CPU to loop in kernel mode
1012 for more than 10 seconds, without letting other interrupts have a
1013 chance to run. The current stack trace is displayed upon detection
1014 and the system will stay locked up.
1016 config BOOTPARAM_HARDLOCKUP_PANIC
1017 bool "Panic (Reboot) On Hard Lockups"
1018 depends on HARDLOCKUP_DETECTOR
1020 Say Y here to enable the kernel to panic on "hard lockups",
1021 which are bugs that cause the kernel to loop in kernel
1022 mode with interrupts disabled for more than 10 seconds (configurable
1023 using the watchdog_thresh sysctl).
1027 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
1029 depends on HARDLOCKUP_DETECTOR
1031 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
1032 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
1034 config DETECT_HUNG_TASK
1035 bool "Detect Hung Tasks"
1036 depends on DEBUG_KERNEL
1037 default SOFTLOCKUP_DETECTOR
1039 Say Y here to enable the kernel to detect "hung tasks",
1040 which are bugs that cause the task to be stuck in
1041 uninterruptible "D" state indefinitely.
1043 When a hung task is detected, the kernel will print the
1044 current stack trace (which you should report), but the
1045 task will stay in uninterruptible state. If lockdep is
1046 enabled then all held locks will also be reported. This
1047 feature has negligible overhead.
1049 config DEFAULT_HUNG_TASK_TIMEOUT
1050 int "Default timeout for hung task detection (in seconds)"
1051 depends on DETECT_HUNG_TASK
1054 This option controls the default timeout (in seconds) used
1055 to determine when a task has become non-responsive and should
1058 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1059 sysctl or by writing a value to
1060 /proc/sys/kernel/hung_task_timeout_secs.
1062 A timeout of 0 disables the check. The default is two minutes.
1063 Keeping the default should be fine in most cases.
1065 config BOOTPARAM_HUNG_TASK_PANIC
1066 bool "Panic (Reboot) On Hung Tasks"
1067 depends on DETECT_HUNG_TASK
1069 Say Y here to enable the kernel to panic on "hung tasks",
1070 which are bugs that cause the kernel to leave a task stuck
1071 in uninterruptible "D" state.
1073 The panic can be used in combination with panic_timeout,
1074 to cause the system to reboot automatically after a
1075 hung task has been detected. This feature is useful for
1076 high-availability systems that have uptime guarantees and
1077 where a hung tasks must be resolved ASAP.
1081 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
1083 depends on DETECT_HUNG_TASK
1085 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
1086 default 1 if BOOTPARAM_HUNG_TASK_PANIC
1089 bool "Detect Workqueue Stalls"
1090 depends on DEBUG_KERNEL
1092 Say Y here to enable stall detection on workqueues. If a
1093 worker pool doesn't make forward progress on a pending work
1094 item for over a given amount of time, 30s by default, a
1095 warning message is printed along with dump of workqueue
1096 state. This can be configured through kernel parameter
1097 "workqueue.watchdog_thresh" and its sysfs counterpart.
1100 tristate "Test module to generate lockups"
1103 This builds the "test_lockup" module that helps to make sure
1104 that watchdogs and lockup detectors are working properly.
1106 Depending on module parameters it could emulate soft or hard
1107 lockup, "hung task", or locking arbitrary lock for a long time.
1108 Also it could generate series of lockups with cooling-down periods.
1112 endmenu # "Debug lockups and hangs"
1114 menu "Scheduler Debugging"
1117 bool "Collect scheduler debugging info"
1118 depends on DEBUG_KERNEL && PROC_FS
1121 If you say Y here, the /proc/sched_debug file will be provided
1122 that can help debug the scheduler. The runtime overhead of this
1130 bool "Collect scheduler statistics"
1131 depends on DEBUG_KERNEL && PROC_FS
1134 If you say Y here, additional code will be inserted into the
1135 scheduler and related routines to collect statistics about
1136 scheduler behavior and provide them in /proc/schedstat. These
1137 stats may be useful for both tuning and debugging the scheduler
1138 If you aren't debugging the scheduler or trying to tune a specific
1139 application, you can say N to avoid the very slight overhead
1144 config DEBUG_TIMEKEEPING
1145 bool "Enable extra timekeeping sanity checking"
1147 This option will enable additional timekeeping sanity checks
1148 which may be helpful when diagnosing issues where timekeeping
1149 problems are suspected.
1151 This may include checks in the timekeeping hotpaths, so this
1152 option may have a (very small) performance impact to some
1157 config DEBUG_PREEMPT
1158 bool "Debug preemptible kernel"
1159 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1162 If you say Y here then the kernel will use a debug variant of the
1163 commonly used smp_processor_id() function and will print warnings
1164 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1165 will detect preemption count underflows.
1167 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1169 config LOCK_DEBUGGING_SUPPORT
1171 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1174 config PROVE_LOCKING
1175 bool "Lock debugging: prove locking correctness"
1176 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1178 select DEBUG_SPINLOCK
1179 select DEBUG_MUTEXES
1180 select DEBUG_RT_MUTEXES if RT_MUTEXES
1182 select DEBUG_WW_MUTEX_SLOWPATH
1183 select DEBUG_LOCK_ALLOC
1184 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1185 select TRACE_IRQFLAGS
1188 This feature enables the kernel to prove that all locking
1189 that occurs in the kernel runtime is mathematically
1190 correct: that under no circumstance could an arbitrary (and
1191 not yet triggered) combination of observed locking
1192 sequences (on an arbitrary number of CPUs, running an
1193 arbitrary number of tasks and interrupt contexts) cause a
1196 In short, this feature enables the kernel to report locking
1197 related deadlocks before they actually occur.
1199 The proof does not depend on how hard and complex a
1200 deadlock scenario would be to trigger: how many
1201 participant CPUs, tasks and irq-contexts would be needed
1202 for it to trigger. The proof also does not depend on
1203 timing: if a race and a resulting deadlock is possible
1204 theoretically (no matter how unlikely the race scenario
1205 is), it will be proven so and will immediately be
1206 reported by the kernel (once the event is observed that
1207 makes the deadlock theoretically possible).
1209 If a deadlock is impossible (i.e. the locking rules, as
1210 observed by the kernel, are mathematically correct), the
1211 kernel reports nothing.
1213 NOTE: this feature can also be enabled for rwlocks, mutexes
1214 and rwsems - in which case all dependencies between these
1215 different locking variants are observed and mapped too, and
1216 the proof of observed correctness is also maintained for an
1217 arbitrary combination of these separate locking variants.
1219 For more details, see Documentation/locking/lockdep-design.rst.
1221 config PROVE_RAW_LOCK_NESTING
1222 bool "Enable raw_spinlock - spinlock nesting checks"
1223 depends on PROVE_LOCKING
1226 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1227 that the lock nesting rules for PREEMPT_RT enabled kernels are
1230 NOTE: There are known nesting problems. So if you enable this
1231 option expect lockdep splats until these problems have been fully
1232 addressed which is work in progress. This config switch allows to
1233 identify and analyze these problems. It will be removed and the
1234 check permanentely enabled once the main issues have been fixed.
1236 If unsure, select N.
1239 bool "Lock usage statistics"
1240 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1242 select DEBUG_SPINLOCK
1243 select DEBUG_MUTEXES
1244 select DEBUG_RT_MUTEXES if RT_MUTEXES
1245 select DEBUG_LOCK_ALLOC
1248 This feature enables tracking lock contention points
1250 For more details, see Documentation/locking/lockstat.rst
1252 This also enables lock events required by "perf lock",
1254 If you want to use "perf lock", you also need to turn on
1255 CONFIG_EVENT_TRACING.
1257 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1258 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1260 config DEBUG_RT_MUTEXES
1261 bool "RT Mutex debugging, deadlock detection"
1262 depends on DEBUG_KERNEL && RT_MUTEXES
1264 This allows rt mutex semantics violations and rt mutex related
1265 deadlocks (lockups) to be detected and reported automatically.
1267 config DEBUG_SPINLOCK
1268 bool "Spinlock and rw-lock debugging: basic checks"
1269 depends on DEBUG_KERNEL
1270 select UNINLINE_SPIN_UNLOCK
1272 Say Y here and build SMP to catch missing spinlock initialization
1273 and certain other kinds of spinlock errors commonly made. This is
1274 best used in conjunction with the NMI watchdog so that spinlock
1275 deadlocks are also debuggable.
1277 config DEBUG_MUTEXES
1278 bool "Mutex debugging: basic checks"
1279 depends on DEBUG_KERNEL
1281 This feature allows mutex semantics violations to be detected and
1284 config DEBUG_WW_MUTEX_SLOWPATH
1285 bool "Wait/wound mutex debugging: Slowpath testing"
1286 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1287 select DEBUG_LOCK_ALLOC
1288 select DEBUG_SPINLOCK
1289 select DEBUG_MUTEXES
1291 This feature enables slowpath testing for w/w mutex users by
1292 injecting additional -EDEADLK wound/backoff cases. Together with
1293 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1294 will test all possible w/w mutex interface abuse with the
1295 exception of simply not acquiring all the required locks.
1296 Note that this feature can introduce significant overhead, so
1297 it really should not be enabled in a production or distro kernel,
1298 even a debug kernel. If you are a driver writer, enable it. If
1299 you are a distro, do not.
1302 bool "RW Semaphore debugging: basic checks"
1303 depends on DEBUG_KERNEL
1305 This debugging feature allows mismatched rw semaphore locks
1306 and unlocks to be detected and reported.
1308 config DEBUG_LOCK_ALLOC
1309 bool "Lock debugging: detect incorrect freeing of live locks"
1310 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1311 select DEBUG_SPINLOCK
1312 select DEBUG_MUTEXES
1313 select DEBUG_RT_MUTEXES if RT_MUTEXES
1316 This feature will check whether any held lock (spinlock, rwlock,
1317 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1318 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1319 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1320 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1321 held during task exit.
1325 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1327 select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86
1331 config LOCKDEP_SMALL
1334 config DEBUG_LOCKDEP
1335 bool "Lock dependency engine debugging"
1336 depends on DEBUG_KERNEL && LOCKDEP
1338 If you say Y here, the lock dependency engine will do
1339 additional runtime checks to debug itself, at the price
1340 of more runtime overhead.
1342 config DEBUG_ATOMIC_SLEEP
1343 bool "Sleep inside atomic section checking"
1344 select PREEMPT_COUNT
1345 depends on DEBUG_KERNEL
1346 depends on !ARCH_NO_PREEMPT
1348 If you say Y here, various routines which may sleep will become very
1349 noisy if they are called inside atomic sections: when a spinlock is
1350 held, inside an rcu read side critical section, inside preempt disabled
1351 sections, inside an interrupt, etc...
1353 config DEBUG_LOCKING_API_SELFTESTS
1354 bool "Locking API boot-time self-tests"
1355 depends on DEBUG_KERNEL
1357 Say Y here if you want the kernel to run a short self-test during
1358 bootup. The self-test checks whether common types of locking bugs
1359 are detected by debugging mechanisms or not. (if you disable
1360 lock debugging then those bugs wont be detected of course.)
1361 The following locking APIs are covered: spinlocks, rwlocks,
1364 config LOCK_TORTURE_TEST
1365 tristate "torture tests for locking"
1366 depends on DEBUG_KERNEL
1369 This option provides a kernel module that runs torture tests
1370 on kernel locking primitives. The kernel module may be built
1371 after the fact on the running kernel to be tested, if desired.
1373 Say Y here if you want kernel locking-primitive torture tests
1374 to be built into the kernel.
1375 Say M if you want these torture tests to build as a module.
1376 Say N if you are unsure.
1378 config WW_MUTEX_SELFTEST
1379 tristate "Wait/wound mutex selftests"
1381 This option provides a kernel module that runs tests on the
1382 on the struct ww_mutex locking API.
1384 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1385 with this test harness.
1387 Say M if you want these self tests to build as a module.
1388 Say N if you are unsure.
1390 config SCF_TORTURE_TEST
1391 tristate "torture tests for smp_call_function*()"
1392 depends on DEBUG_KERNEL
1395 This option provides a kernel module that runs torture tests
1396 on the smp_call_function() family of primitives. The kernel
1397 module may be built after the fact on the running kernel to
1398 be tested, if desired.
1400 config CSD_LOCK_WAIT_DEBUG
1401 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1402 depends on DEBUG_KERNEL
1406 This option enables debug prints when CPUs are slow to respond
1407 to the smp_call_function*() IPI wrappers. These debug prints
1408 include the IPI handler function currently executing (if any)
1409 and relevant stack traces.
1411 endmenu # lock debugging
1413 config TRACE_IRQFLAGS
1414 depends on TRACE_IRQFLAGS_SUPPORT
1417 Enables hooks to interrupt enabling and disabling for
1418 either tracing or lock debugging.
1420 config TRACE_IRQFLAGS_NMI
1422 depends on TRACE_IRQFLAGS
1423 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1426 bool "Stack backtrace support"
1427 depends on STACKTRACE_SUPPORT
1429 This option causes the kernel to create a /proc/pid/stack for
1430 every process, showing its current stack trace.
1431 It is also used by various kernel debugging features that require
1432 stack trace generation.
1434 config WARN_ALL_UNSEEDED_RANDOM
1435 bool "Warn for all uses of unseeded randomness"
1438 Some parts of the kernel contain bugs relating to their use of
1439 cryptographically secure random numbers before it's actually possible
1440 to generate those numbers securely. This setting ensures that these
1441 flaws don't go unnoticed, by enabling a message, should this ever
1442 occur. This will allow people with obscure setups to know when things
1443 are going wrong, so that they might contact developers about fixing
1446 Unfortunately, on some models of some architectures getting
1447 a fully seeded CRNG is extremely difficult, and so this can
1448 result in dmesg getting spammed for a surprisingly long
1449 time. This is really bad from a security perspective, and
1450 so architecture maintainers really need to do what they can
1451 to get the CRNG seeded sooner after the system is booted.
1452 However, since users cannot do anything actionable to
1453 address this, by default the kernel will issue only a single
1454 warning for the first use of unseeded randomness.
1456 Say Y here if you want to receive warnings for all uses of
1457 unseeded randomness. This will be of use primarily for
1458 those developers interested in improving the security of
1459 Linux kernels running on their architecture (or
1462 config DEBUG_KOBJECT
1463 bool "kobject debugging"
1464 depends on DEBUG_KERNEL
1466 If you say Y here, some extra kobject debugging messages will be sent
1469 config DEBUG_KOBJECT_RELEASE
1470 bool "kobject release debugging"
1471 depends on DEBUG_OBJECTS_TIMERS
1473 kobjects are reference counted objects. This means that their
1474 last reference count put is not predictable, and the kobject can
1475 live on past the point at which a driver decides to drop it's
1476 initial reference to the kobject gained on allocation. An
1477 example of this would be a struct device which has just been
1480 However, some buggy drivers assume that after such an operation,
1481 the memory backing the kobject can be immediately freed. This
1482 goes completely against the principles of a refcounted object.
1484 If you say Y here, the kernel will delay the release of kobjects
1485 on the last reference count to improve the visibility of this
1486 kind of kobject release bug.
1488 config HAVE_DEBUG_BUGVERBOSE
1491 menu "Debug kernel data structures"
1494 bool "Debug linked list manipulation"
1495 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1497 Enable this to turn on extended checks in the linked-list
1503 bool "Debug priority linked list manipulation"
1504 depends on DEBUG_KERNEL
1506 Enable this to turn on extended checks in the priority-ordered
1507 linked-list (plist) walking routines. This checks the entire
1508 list multiple times during each manipulation.
1513 bool "Debug SG table operations"
1514 depends on DEBUG_KERNEL
1516 Enable this to turn on checks on scatter-gather tables. This can
1517 help find problems with drivers that do not properly initialize
1522 config DEBUG_NOTIFIERS
1523 bool "Debug notifier call chains"
1524 depends on DEBUG_KERNEL
1526 Enable this to turn on sanity checking for notifier call chains.
1527 This is most useful for kernel developers to make sure that
1528 modules properly unregister themselves from notifier chains.
1529 This is a relatively cheap check but if you care about maximum
1532 config BUG_ON_DATA_CORRUPTION
1533 bool "Trigger a BUG when data corruption is detected"
1536 Select this option if the kernel should BUG when it encounters
1537 data corruption in kernel memory structures when they get checked
1544 config DEBUG_CREDENTIALS
1545 bool "Debug credential management"
1546 depends on DEBUG_KERNEL
1548 Enable this to turn on some debug checking for credential
1549 management. The additional code keeps track of the number of
1550 pointers from task_structs to any given cred struct, and checks to
1551 see that this number never exceeds the usage count of the cred
1554 Furthermore, if SELinux is enabled, this also checks that the
1555 security pointer in the cred struct is never seen to be invalid.
1559 source "kernel/rcu/Kconfig.debug"
1561 config DEBUG_WQ_FORCE_RR_CPU
1562 bool "Force round-robin CPU selection for unbound work items"
1563 depends on DEBUG_KERNEL
1566 Workqueue used to implicitly guarantee that work items queued
1567 without explicit CPU specified are put on the local CPU. This
1568 guarantee is no longer true and while local CPU is still
1569 preferred work items may be put on foreign CPUs. Kernel
1570 parameter "workqueue.debug_force_rr_cpu" is added to force
1571 round-robin CPU selection to flush out usages which depend on the
1572 now broken guarantee. This config option enables the debug
1573 feature by default. When enabled, memory and cache locality will
1576 config DEBUG_BLOCK_EXT_DEVT
1577 bool "Force extended block device numbers and spread them"
1578 depends on DEBUG_KERNEL
1582 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1583 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1584 YOU ARE DOING. Distros, please enable this and fix whatever
1587 Conventionally, block device numbers are allocated from
1588 predetermined contiguous area. However, extended block area
1589 may introduce non-contiguous block device numbers. This
1590 option forces most block device numbers to be allocated from
1591 the extended space and spreads them to discover kernel or
1592 userland code paths which assume predetermined contiguous
1593 device number allocation.
1595 Note that turning on this debug option shuffles all the
1596 device numbers for all IDE and SCSI devices including libata
1597 ones, so root partition specified using device number
1598 directly (via rdev or root=MAJ:MIN) won't work anymore.
1599 Textual device names (root=/dev/sdXn) will continue to work.
1601 Say N if you are unsure.
1603 config CPU_HOTPLUG_STATE_CONTROL
1604 bool "Enable CPU hotplug state control"
1605 depends on DEBUG_KERNEL
1606 depends on HOTPLUG_CPU
1609 Allows to write steps between "offline" and "online" to the CPUs
1610 sysfs target file so states can be stepped granular. This is a debug
1611 option for now as the hotplug machinery cannot be stopped and
1612 restarted at arbitrary points yet.
1614 Say N if your are unsure.
1617 bool "Latency measuring infrastructure"
1618 depends on DEBUG_KERNEL
1619 depends on STACKTRACE_SUPPORT
1621 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
1628 Enable this option if you want to use the LatencyTOP tool
1629 to find out which userspace is blocking on what kernel operations.
1631 source "kernel/trace/Kconfig"
1633 config PROVIDE_OHCI1394_DMA_INIT
1634 bool "Remote debugging over FireWire early on boot"
1635 depends on PCI && X86
1637 If you want to debug problems which hang or crash the kernel early
1638 on boot and the crashing machine has a FireWire port, you can use
1639 this feature to remotely access the memory of the crashed machine
1640 over FireWire. This employs remote DMA as part of the OHCI1394
1641 specification which is now the standard for FireWire controllers.
1643 With remote DMA, you can monitor the printk buffer remotely using
1644 firescope and access all memory below 4GB using fireproxy from gdb.
1645 Even controlling a kernel debugger is possible using remote DMA.
1649 If ohci1394_dma=early is used as boot parameter, it will initialize
1650 all OHCI1394 controllers which are found in the PCI config space.
1652 As all changes to the FireWire bus such as enabling and disabling
1653 devices cause a bus reset and thereby disable remote DMA for all
1654 devices, be sure to have the cable plugged and FireWire enabled on
1655 the debugging host before booting the debug target for debugging.
1657 This code (~1k) is freed after boot. By then, the firewire stack
1658 in charge of the OHCI-1394 controllers should be used instead.
1660 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1662 source "samples/Kconfig"
1664 config ARCH_HAS_DEVMEM_IS_ALLOWED
1667 config STRICT_DEVMEM
1668 bool "Filter access to /dev/mem"
1669 depends on MMU && DEVMEM
1670 depends on ARCH_HAS_DEVMEM_IS_ALLOWED
1671 default y if PPC || X86 || ARM64
1673 If this option is disabled, you allow userspace (root) access to all
1674 of memory, including kernel and userspace memory. Accidental
1675 access to this is obviously disastrous, but specific access can
1676 be used by people debugging the kernel. Note that with PAT support
1677 enabled, even in this case there are restrictions on /dev/mem
1678 use due to the cache aliasing requirements.
1680 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1681 file only allows userspace access to PCI space and the BIOS code and
1682 data regions. This is sufficient for dosemu and X and all common
1687 config IO_STRICT_DEVMEM
1688 bool "Filter I/O access to /dev/mem"
1689 depends on STRICT_DEVMEM
1691 If this option is disabled, you allow userspace (root) access to all
1692 io-memory regardless of whether a driver is actively using that
1693 range. Accidental access to this is obviously disastrous, but
1694 specific access can be used by people debugging kernel drivers.
1696 If this option is switched on, the /dev/mem file only allows
1697 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1698 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1699 if the driver using a given range cannot be disabled.
1703 menu "$(SRCARCH) Debugging"
1705 source "arch/$(SRCARCH)/Kconfig.debug"
1709 menu "Kernel Testing and Coverage"
1711 source "lib/kunit/Kconfig"
1713 config NOTIFIER_ERROR_INJECTION
1714 tristate "Notifier error injection"
1715 depends on DEBUG_KERNEL
1718 This option provides the ability to inject artificial errors to
1719 specified notifier chain callbacks. It is useful to test the error
1720 handling of notifier call chain failures.
1724 config PM_NOTIFIER_ERROR_INJECT
1725 tristate "PM notifier error injection module"
1726 depends on PM && NOTIFIER_ERROR_INJECTION
1727 default m if PM_DEBUG
1729 This option provides the ability to inject artificial errors to
1730 PM notifier chain callbacks. It is controlled through debugfs
1731 interface /sys/kernel/debug/notifier-error-inject/pm
1733 If the notifier call chain should be failed with some events
1734 notified, write the error code to "actions/<notifier event>/error".
1736 Example: Inject PM suspend error (-12 = -ENOMEM)
1738 # cd /sys/kernel/debug/notifier-error-inject/pm/
1739 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1740 # echo mem > /sys/power/state
1741 bash: echo: write error: Cannot allocate memory
1743 To compile this code as a module, choose M here: the module will
1744 be called pm-notifier-error-inject.
1748 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1749 tristate "OF reconfig notifier error injection module"
1750 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1752 This option provides the ability to inject artificial errors to
1753 OF reconfig notifier chain callbacks. It is controlled
1754 through debugfs interface under
1755 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1757 If the notifier call chain should be failed with some events
1758 notified, write the error code to "actions/<notifier event>/error".
1760 To compile this code as a module, choose M here: the module will
1761 be called of-reconfig-notifier-error-inject.
1765 config NETDEV_NOTIFIER_ERROR_INJECT
1766 tristate "Netdev notifier error injection module"
1767 depends on NET && NOTIFIER_ERROR_INJECTION
1769 This option provides the ability to inject artificial errors to
1770 netdevice notifier chain callbacks. It is controlled through debugfs
1771 interface /sys/kernel/debug/notifier-error-inject/netdev
1773 If the notifier call chain should be failed with some events
1774 notified, write the error code to "actions/<notifier event>/error".
1776 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1778 # cd /sys/kernel/debug/notifier-error-inject/netdev
1779 # echo -22 > actions/NETDEV_CHANGEMTU/error
1780 # ip link set eth0 mtu 1024
1781 RTNETLINK answers: Invalid argument
1783 To compile this code as a module, choose M here: the module will
1784 be called netdev-notifier-error-inject.
1788 config FUNCTION_ERROR_INJECTION
1790 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1792 config FAULT_INJECTION
1793 bool "Fault-injection framework"
1794 depends on DEBUG_KERNEL
1796 Provide fault-injection framework.
1797 For more details, see Documentation/fault-injection/.
1800 bool "Fault-injection capability for kmalloc"
1801 depends on FAULT_INJECTION
1802 depends on SLAB || SLUB
1804 Provide fault-injection capability for kmalloc.
1806 config FAIL_PAGE_ALLOC
1807 bool "Fault-injection capability for alloc_pages()"
1808 depends on FAULT_INJECTION
1810 Provide fault-injection capability for alloc_pages().
1812 config FAULT_INJECTION_USERCOPY
1813 bool "Fault injection capability for usercopy functions"
1814 depends on FAULT_INJECTION
1816 Provides fault-injection capability to inject failures
1817 in usercopy functions (copy_from_user(), get_user(), ...).
1819 config FAIL_MAKE_REQUEST
1820 bool "Fault-injection capability for disk IO"
1821 depends on FAULT_INJECTION && BLOCK
1823 Provide fault-injection capability for disk IO.
1825 config FAIL_IO_TIMEOUT
1826 bool "Fault-injection capability for faking disk interrupts"
1827 depends on FAULT_INJECTION && BLOCK
1829 Provide fault-injection capability on end IO handling. This
1830 will make the block layer "forget" an interrupt as configured,
1831 thus exercising the error handling.
1833 Only works with drivers that use the generic timeout handling,
1834 for others it wont do anything.
1837 bool "Fault-injection capability for futexes"
1839 depends on FAULT_INJECTION && FUTEX
1841 Provide fault-injection capability for futexes.
1843 config FAULT_INJECTION_DEBUG_FS
1844 bool "Debugfs entries for fault-injection capabilities"
1845 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1847 Enable configuration of fault-injection capabilities via debugfs.
1849 config FAIL_FUNCTION
1850 bool "Fault-injection capability for functions"
1851 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1853 Provide function-based fault-injection capability.
1854 This will allow you to override a specific function with a return
1855 with given return value. As a result, function caller will see
1856 an error value and have to handle it. This is useful to test the
1857 error handling in various subsystems.
1859 config FAIL_MMC_REQUEST
1860 bool "Fault-injection capability for MMC IO"
1861 depends on FAULT_INJECTION_DEBUG_FS && MMC
1863 Provide fault-injection capability for MMC IO.
1864 This will make the mmc core return data errors. This is
1865 useful to test the error handling in the mmc block device
1866 and to test how the mmc host driver handles retries from
1869 config FAULT_INJECTION_STACKTRACE_FILTER
1870 bool "stacktrace filter for fault-injection capabilities"
1871 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1874 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
1876 Provide stacktrace filter for fault-injection capabilities
1878 config ARCH_HAS_KCOV
1881 An architecture should select this when it can successfully
1882 build and run with CONFIG_KCOV. This typically requires
1883 disabling instrumentation for some early boot code.
1885 config CC_HAS_SANCOV_TRACE_PC
1886 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1890 bool "Code coverage for fuzzing"
1891 depends on ARCH_HAS_KCOV
1892 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1894 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1896 KCOV exposes kernel code coverage information in a form suitable
1897 for coverage-guided fuzzing (randomized testing).
1899 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1900 different machines and across reboots. If you need stable PC values,
1901 disable RANDOMIZE_BASE.
1903 For more details, see Documentation/dev-tools/kcov.rst.
1905 config KCOV_ENABLE_COMPARISONS
1906 bool "Enable comparison operands collection by KCOV"
1908 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
1910 KCOV also exposes operands of every comparison in the instrumented
1911 code along with operand sizes and PCs of the comparison instructions.
1912 These operands can be used by fuzzing engines to improve the quality
1913 of fuzzing coverage.
1915 config KCOV_INSTRUMENT_ALL
1916 bool "Instrument all code by default"
1920 If you are doing generic system call fuzzing (like e.g. syzkaller),
1921 then you will want to instrument the whole kernel and you should
1922 say y here. If you are doing more targeted fuzzing (like e.g.
1923 filesystem fuzzing with AFL) then you will want to enable coverage
1924 for more specific subsets of files, and should say n here.
1926 config KCOV_IRQ_AREA_SIZE
1927 hex "Size of interrupt coverage collection area in words"
1931 KCOV uses preallocated per-cpu areas to collect coverage from
1932 soft interrupts. This specifies the size of those areas in the
1933 number of unsigned long words.
1935 menuconfig RUNTIME_TESTING_MENU
1936 bool "Runtime Testing"
1939 if RUNTIME_TESTING_MENU
1942 tristate "Linux Kernel Dump Test Tool Module"
1945 This module enables testing of the different dumping mechanisms by
1946 inducing system failures at predefined crash points.
1947 If you don't need it: say N
1948 Choose M here to compile this code as a module. The module will be
1951 Documentation on how to use the module can be found in
1952 Documentation/fault-injection/provoke-crashes.rst
1954 config TEST_LIST_SORT
1955 tristate "Linked list sorting test"
1956 depends on DEBUG_KERNEL || m
1958 Enable this to turn on 'list_sort()' function test. This test is
1959 executed only once during system boot (so affects only boot time),
1960 or at module load time.
1964 config TEST_MIN_HEAP
1965 tristate "Min heap test"
1966 depends on DEBUG_KERNEL || m
1968 Enable this to turn on min heap function tests. This test is
1969 executed only once during system boot (so affects only boot time),
1970 or at module load time.
1975 tristate "Array-based sort test"
1976 depends on DEBUG_KERNEL || m
1978 This option enables the self-test function of 'sort()' at boot,
1979 or at module load time.
1983 config KPROBES_SANITY_TEST
1984 bool "Kprobes sanity tests"
1985 depends on DEBUG_KERNEL
1988 This option provides for testing basic kprobes functionality on
1989 boot. Samples of kprobe and kretprobe are inserted and
1990 verified for functionality.
1992 Say N if you are unsure.
1994 config BACKTRACE_SELF_TEST
1995 tristate "Self test for the backtrace code"
1996 depends on DEBUG_KERNEL
1998 This option provides a kernel module that can be used to test
1999 the kernel stack backtrace code. This option is not useful
2000 for distributions or general kernels, but only for kernel
2001 developers working on architecture code.
2003 Note that if you want to also test saved backtraces, you will
2004 have to enable STACKTRACE as well.
2006 Say N if you are unsure.
2009 tristate "Red-Black tree test"
2010 depends on DEBUG_KERNEL
2012 A benchmark measuring the performance of the rbtree library.
2013 Also includes rbtree invariant checks.
2015 config REED_SOLOMON_TEST
2016 tristate "Reed-Solomon library test"
2017 depends on DEBUG_KERNEL || m
2019 select REED_SOLOMON_ENC16
2020 select REED_SOLOMON_DEC16
2022 This option enables the self-test function of rslib at boot,
2023 or at module load time.
2027 config INTERVAL_TREE_TEST
2028 tristate "Interval tree test"
2029 depends on DEBUG_KERNEL
2030 select INTERVAL_TREE
2032 A benchmark measuring the performance of the interval tree library
2035 tristate "Per cpu operations test"
2036 depends on m && DEBUG_KERNEL
2038 Enable this option to build test module which validates per-cpu
2043 config ATOMIC64_SELFTEST
2044 tristate "Perform an atomic64_t self-test"
2046 Enable this option to test the atomic64_t functions at boot or
2047 at module load time.
2051 config ASYNC_RAID6_TEST
2052 tristate "Self test for hardware accelerated raid6 recovery"
2053 depends on ASYNC_RAID6_RECOV
2056 This is a one-shot self test that permutes through the
2057 recovery of all the possible two disk failure scenarios for a
2058 N-disk array. Recovery is performed with the asynchronous
2059 raid6 recovery routines, and will optionally use an offload
2060 engine if one is available.
2065 tristate "Test functions located in the hexdump module at runtime"
2067 config TEST_STRING_HELPERS
2068 tristate "Test functions located in the string_helpers module at runtime"
2071 tristate "Test strscpy*() family of functions at runtime"
2074 tristate "Test kstrto*() family of functions at runtime"
2077 tristate "Test printf() family of functions at runtime"
2080 tristate "Test bitmap_*() family of functions at runtime"
2082 Enable this option to test the bitmap functions at boot.
2087 tristate "Test functions located in the uuid module at runtime"
2090 tristate "Test the XArray code at runtime"
2092 config TEST_OVERFLOW
2093 tristate "Test check_*_overflow() functions at runtime"
2095 config TEST_RHASHTABLE
2096 tristate "Perform selftest on resizable hash table"
2098 Enable this option to test the rhashtable functions at boot.
2103 tristate "Perform selftest on hash functions"
2105 Enable this option to test the kernel's integer (<linux/hash.h>),
2106 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
2107 hash functions on boot (or module load).
2109 This is intended to help people writing architecture-specific
2110 optimized versions. If unsure, say N.
2113 tristate "Perform selftest on IDA functions"
2116 tristate "Perform selftest on priority array manager"
2119 Enable this option to test priority array manager on boot
2124 config TEST_IRQ_TIMINGS
2125 bool "IRQ timings selftest"
2126 depends on IRQ_TIMINGS
2128 Enable this option to test the irq timings code on boot.
2133 tristate "Test module loading with 'hello world' module"
2136 This builds the "test_module" module that emits "Hello, world"
2137 on printk when loaded. It is designed to be used for basic
2138 evaluation of the module loading subsystem (for example when
2139 validating module verification). It lacks any extra dependencies,
2140 and will not normally be loaded by the system unless explicitly
2146 tristate "Test module for compilation of bitops operations"
2149 This builds the "test_bitops" module that is much like the
2150 TEST_LKM module except that it does a basic exercise of the
2151 set/clear_bit macros and get_count_order/long to make sure there are
2152 no compiler warnings from C=1 sparse checker or -Wextra
2153 compilations. It has no dependencies and doesn't run or load unless
2154 explicitly requested by name. for example: modprobe test_bitops.
2159 tristate "Test module for stress/performance analysis of vmalloc allocator"
2164 This builds the "test_vmalloc" module that should be used for
2165 stress and performance analysis. So, any new change for vmalloc
2166 subsystem can be evaluated from performance and stability point
2171 config TEST_USER_COPY
2172 tristate "Test user/kernel boundary protections"
2175 This builds the "test_user_copy" module that runs sanity checks
2176 on the copy_to/from_user infrastructure, making sure basic
2177 user/kernel boundary testing is working. If it fails to load,
2178 a regression has been detected in the user/kernel memory boundary
2184 tristate "Test BPF filter functionality"
2187 This builds the "test_bpf" module that runs various test vectors
2188 against the BPF interpreter or BPF JIT compiler depending on the
2189 current setting. This is in particular useful for BPF JIT compiler
2190 development, but also to run regression tests against changes in
2191 the interpreter code. It also enables test stubs for eBPF maps and
2192 verifier used by user space verifier testsuite.
2196 config TEST_BLACKHOLE_DEV
2197 tristate "Test blackhole netdev functionality"
2200 This builds the "test_blackhole_dev" module that validates the
2201 data path through this blackhole netdev.
2205 config FIND_BIT_BENCHMARK
2206 tristate "Test find_bit functions"
2208 This builds the "test_find_bit" module that measure find_*_bit()
2209 functions performance.
2213 config TEST_FIRMWARE
2214 tristate "Test firmware loading via userspace interface"
2215 depends on FW_LOADER
2217 This builds the "test_firmware" module that creates a userspace
2218 interface for testing firmware loading. This can be used to
2219 control the triggering of firmware loading without needing an
2220 actual firmware-using device. The contents can be rechecked by
2226 tristate "sysctl test driver"
2227 depends on PROC_SYSCTL
2229 This builds the "test_sysctl" module. This driver enables to test the
2230 proc sysctl interfaces available to drivers safely without affecting
2231 production knobs which might alter system functionality.
2235 config BITFIELD_KUNIT
2236 tristate "KUnit test bitfield functions at runtime"
2239 Enable this option to test the bitfield functions at boot.
2241 KUnit tests run during boot and output the results to the debug log
2242 in TAP format (http://testanything.org/). Only useful for kernel devs
2243 running the KUnit test harness, and not intended for inclusion into a
2246 For more information on KUnit and unit tests in general please refer
2247 to the KUnit documentation in Documentation/dev-tools/kunit/.
2251 config SYSCTL_KUNIT_TEST
2252 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2254 default KUNIT_ALL_TESTS
2256 This builds the proc sysctl unit test, which runs on boot.
2257 Tests the API contract and implementation correctness of sysctl.
2258 For more information on KUnit and unit tests in general please refer
2259 to the KUnit documentation in Documentation/dev-tools/kunit/.
2263 config LIST_KUNIT_TEST
2264 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2266 default KUNIT_ALL_TESTS
2268 This builds the linked list KUnit test suite.
2269 It tests that the API and basic functionality of the list_head type
2270 and associated macros.
2272 KUnit tests run during boot and output the results to the debug log
2273 in TAP format (https://testanything.org/). Only useful for kernel devs
2274 running the KUnit test harness, and not intended for inclusion into a
2277 For more information on KUnit and unit tests in general please refer
2278 to the KUnit documentation in Documentation/dev-tools/kunit/.
2282 config LINEAR_RANGES_TEST
2283 tristate "KUnit test for linear_ranges"
2285 select LINEAR_RANGES
2287 This builds the linear_ranges unit test, which runs on boot.
2288 Tests the linear_ranges logic correctness.
2289 For more information on KUnit and unit tests in general please refer
2290 to the KUnit documentation in Documentation/dev-tools/kunit/.
2295 tristate "KUnit test for bits.h"
2298 This builds the bits unit test.
2299 Tests the logic of macros defined in bits.h.
2300 For more information on KUnit and unit tests in general please refer
2301 to the KUnit documentation in Documentation/dev-tools/kunit/.
2306 tristate "udelay test driver"
2308 This builds the "udelay_test" module that helps to make sure
2309 that udelay() is working properly.
2313 config TEST_STATIC_KEYS
2314 tristate "Test static keys"
2317 Test the static key interfaces.
2322 tristate "kmod stress tester"
2324 depends on NETDEVICES && NET_CORE && INET # for TUN
2331 Test the kernel's module loading mechanism: kmod. kmod implements
2332 support to load modules using the Linux kernel's usermode helper.
2333 This test provides a series of tests against kmod.
2335 Although technically you can either build test_kmod as a module or
2336 into the kernel we disallow building it into the kernel since
2337 it stress tests request_module() and this will very likely cause
2338 some issues by taking over precious threads available from other
2339 module load requests, ultimately this could be fatal.
2343 tools/testing/selftests/kmod/kmod.sh --help
2347 config TEST_DEBUG_VIRTUAL
2348 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2349 depends on DEBUG_VIRTUAL
2351 Test the kernel's ability to detect incorrect calls to
2352 virt_to_phys() done against the non-linear part of the
2353 kernel's virtual address map.
2357 config TEST_MEMCAT_P
2358 tristate "Test memcat_p() helper function"
2360 Test the memcat_p() helper for correctly merging two
2361 pointer arrays together.
2365 config TEST_LIVEPATCH
2366 tristate "Test livepatching"
2368 depends on DYNAMIC_DEBUG
2369 depends on LIVEPATCH
2372 Test kernel livepatching features for correctness. The tests will
2373 load test modules that will be livepatched in various scenarios.
2375 To run all the livepatching tests:
2377 make -C tools/testing/selftests TARGETS=livepatch run_tests
2379 Alternatively, individual tests may be invoked:
2381 tools/testing/selftests/livepatch/test-callbacks.sh
2382 tools/testing/selftests/livepatch/test-livepatch.sh
2383 tools/testing/selftests/livepatch/test-shadow-vars.sh
2388 tristate "Perform selftest on object aggreration manager"
2392 Enable this option to test object aggregation manager on boot
2396 config TEST_STACKINIT
2397 tristate "Test level of stack variable initialization"
2399 Test if the kernel is zero-initializing stack variables and
2400 padding. Coverage is controlled by compiler flags,
2401 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2402 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2407 tristate "Test heap/page initialization"
2409 Test if the kernel is zero-initializing heap and page allocations.
2410 This can be useful to test init_on_alloc and init_on_free features.
2415 tristate "Test HMM (Heterogeneous Memory Management)"
2416 depends on TRANSPARENT_HUGEPAGE
2417 depends on DEVICE_PRIVATE
2421 This is a pseudo device driver solely for testing HMM.
2422 Say M here if you want to build the HMM test module.
2423 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2427 config TEST_FREE_PAGES
2428 tristate "Test freeing pages"
2430 Test that a memory leak does not occur due to a race between
2431 freeing a block of pages and a speculative page reference.
2432 Loading this module is safe if your kernel has the bug fixed.
2433 If the bug is not fixed, it will leak gigabytes of memory and
2434 probably OOM your system.
2437 tristate "Test floating point operations in kernel space"
2438 depends on X86 && !KCOV_INSTRUMENT_ALL
2440 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2441 which will trigger a sequence of floating point operations. This is used
2442 for self-testing floating point control register setting in
2447 endif # RUNTIME_TESTING_MENU
2452 This option adds a kernel parameter 'memtest', which allows memtest
2454 memtest=0, mean disabled; -- default
2455 memtest=1, mean do 1 test pattern;
2457 memtest=17, mean do 17 test patterns.
2458 If you are unsure how to answer this question, answer N.
2462 config HYPERV_TESTING
2463 bool "Microsoft Hyper-V driver testing"
2465 depends on HYPERV && DEBUG_FS
2467 Select this option to enable Hyper-V vmbus testing.
2469 endmenu # "Kernel Testing and Coverage"
2471 source "Documentation/Kconfig"
2473 endmenu # Kernel hacking