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.
260 prompt "DWARF version"
262 Which version of DWARF debug info to emit.
264 config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
265 bool "Rely on the toolchain's implicit default DWARF version"
267 The implicit default version of DWARF debug info produced by a
268 toolchain changes over time.
270 This can break consumers of the debug info that haven't upgraded to
271 support newer revisions, and prevent testing newer versions, but
272 those should be less common scenarios.
276 config DEBUG_INFO_DWARF4
277 bool "Generate DWARF Version 4 debuginfo"
279 Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+.
281 If you have consumers of DWARF debug info that are not ready for
282 newer revisions of DWARF, you may wish to choose this or have your
285 endchoice # "DWARF version"
287 config DEBUG_INFO_BTF
288 bool "Generate BTF typeinfo"
289 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
290 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
292 Generate deduplicated BTF type information from DWARF debug info.
293 Turning this on expects presence of pahole tool, which will convert
294 DWARF type info into equivalent deduplicated BTF type info.
296 config PAHOLE_HAS_SPLIT_BTF
297 def_bool $(success, test `$(PAHOLE) --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/'` -ge "119")
299 config DEBUG_INFO_BTF_MODULES
301 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
303 Generate compact split BTF type information for kernel modules.
306 bool "Provide GDB scripts for kernel debugging"
308 This creates the required links to GDB helper scripts in the
309 build directory. If you load vmlinux into gdb, the helper
310 scripts will be automatically imported by gdb as well, and
311 additional functions are available to analyze a Linux kernel
312 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
318 int "Warn for stack frames larger than"
320 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
321 default 1280 if (!64BIT && PARISC)
322 default 1024 if (!64BIT && !PARISC)
323 default 2048 if 64BIT
325 Tell gcc to warn at build time for stack frames larger than this.
326 Setting this too low will cause a lot of warnings.
327 Setting it to 0 disables the warning.
329 config STRIP_ASM_SYMS
330 bool "Strip assembler-generated symbols during link"
333 Strip internal assembler-generated symbols during a link (symbols
334 that look like '.Lxxx') so they don't pollute the output of
335 get_wchan() and suchlike.
338 bool "Generate readable assembler code"
339 depends on DEBUG_KERNEL
341 Disable some compiler optimizations that tend to generate human unreadable
342 assembler output. This may make the kernel slightly slower, but it helps
343 to keep kernel developers who have to stare a lot at assembler listings
346 config HEADERS_INSTALL
347 bool "Install uapi headers to usr/include"
350 This option will install uapi headers (headers exported to user-space)
351 into the usr/include directory for use during the kernel build.
352 This is unneeded for building the kernel itself, but needed for some
353 user-space program samples. It is also needed by some features such
354 as uapi header sanity checks.
356 config DEBUG_SECTION_MISMATCH
357 bool "Enable full Section mismatch analysis"
359 The section mismatch analysis checks if there are illegal
360 references from one section to another section.
361 During linktime or runtime, some sections are dropped;
362 any use of code/data previously in these sections would
363 most likely result in an oops.
364 In the code, functions and variables are annotated with
365 __init,, etc. (see the full list in include/linux/init.h),
366 which results in the code/data being placed in specific sections.
367 The section mismatch analysis is always performed after a full
368 kernel build, and enabling this option causes the following
369 additional step to occur:
370 - Add the option -fno-inline-functions-called-once to gcc commands.
371 When inlining a function annotated with __init in a non-init
372 function, we would lose the section information and thus
373 the analysis would not catch the illegal reference.
374 This option tells gcc to inline less (but it does result in
377 config SECTION_MISMATCH_WARN_ONLY
378 bool "Make section mismatch errors non-fatal"
381 If you say N here, the build process will fail if there are any
382 section mismatch, instead of just throwing warnings.
386 config DEBUG_FORCE_FUNCTION_ALIGN_32B
387 bool "Force all function address 32B aligned" if EXPERT
389 There are cases that a commit from one domain changes the function
390 address alignment of other domains, and cause magic performance
391 bump (regression or improvement). Enable this option will help to
392 verify if the bump is caused by function alignment changes, while
393 it will slightly increase the kernel size and affect icache usage.
395 It is mainly for debug and performance tuning use.
398 # Select this config option from the architecture Kconfig, if it
399 # is preferred to always offer frame pointers as a config
400 # option on the architecture (regardless of KERNEL_DEBUG):
402 config ARCH_WANT_FRAME_POINTERS
406 bool "Compile the kernel with frame pointers"
407 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
408 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
410 If you say Y here the resulting kernel image will be slightly
411 larger and slower, but it gives very useful debugging information
412 in case of kernel bugs. (precise oopses/stacktraces/warnings)
414 config STACK_VALIDATION
415 bool "Compile-time stack metadata validation"
416 depends on HAVE_STACK_VALIDATION
419 Add compile-time checks to validate stack metadata, including frame
420 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
421 that runtime stack traces are more reliable.
423 This is also a prerequisite for generation of ORC unwind data, which
424 is needed for CONFIG_UNWINDER_ORC.
426 For more information, see
427 tools/objtool/Documentation/stack-validation.txt.
429 config VMLINUX_VALIDATION
431 depends on STACK_VALIDATION && DEBUG_ENTRY && !PARAVIRT
434 config DEBUG_FORCE_WEAK_PER_CPU
435 bool "Force weak per-cpu definitions"
436 depends on DEBUG_KERNEL
438 s390 and alpha require percpu variables in modules to be
439 defined weak to work around addressing range issue which
440 puts the following two restrictions on percpu variable
443 1. percpu symbols must be unique whether static or not
444 2. percpu variables can't be defined inside a function
446 To ensure that generic code follows the above rules, this
447 option forces all percpu variables to be defined as weak.
449 endmenu # "Compiler options"
451 menu "Generic Kernel Debugging Instruments"
454 bool "Magic SysRq key"
457 If you say Y here, you will have some control over the system even
458 if the system crashes for example during kernel debugging (e.g., you
459 will be able to flush the buffer cache to disk, reboot the system
460 immediately or dump some status information). This is accomplished
461 by pressing various keys while holding SysRq (Alt+PrintScreen). It
462 also works on a serial console (on PC hardware at least), if you
463 send a BREAK and then within 5 seconds a command keypress. The
464 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
465 Don't say Y unless you really know what this hack does.
467 config MAGIC_SYSRQ_DEFAULT_ENABLE
468 hex "Enable magic SysRq key functions by default"
469 depends on MAGIC_SYSRQ
472 Specifies which SysRq key functions are enabled by default.
473 This may be set to 1 or 0 to enable or disable them all, or
474 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
476 config MAGIC_SYSRQ_SERIAL
477 bool "Enable magic SysRq key over serial"
478 depends on MAGIC_SYSRQ
481 Many embedded boards have a disconnected TTL level serial which can
482 generate some garbage that can lead to spurious false sysrq detects.
483 This option allows you to decide whether you want to enable the
486 config MAGIC_SYSRQ_SERIAL_SEQUENCE
487 string "Char sequence that enables magic SysRq over serial"
488 depends on MAGIC_SYSRQ_SERIAL
491 Specifies a sequence of characters that can follow BREAK to enable
492 SysRq on a serial console.
494 If unsure, leave an empty string and the option will not be enabled.
497 bool "Debug Filesystem"
499 debugfs is a virtual file system that kernel developers use to put
500 debugging files into. Enable this option to be able to read and
501 write to these files.
503 For detailed documentation on the debugfs API, see
504 Documentation/filesystems/.
509 prompt "Debugfs default access"
511 default DEBUG_FS_ALLOW_ALL
513 This selects the default access restrictions for debugfs.
514 It can be overridden with kernel command line option
515 debugfs=[on,no-mount,off]. The restrictions apply for API access
516 and filesystem registration.
518 config DEBUG_FS_ALLOW_ALL
521 No restrictions apply. Both API and filesystem registration
522 is on. This is the normal default operation.
524 config DEBUG_FS_DISALLOW_MOUNT
525 bool "Do not register debugfs as filesystem"
527 The API is open but filesystem is not loaded. Clients can still do
528 their work and read with debug tools that do not need
531 config DEBUG_FS_ALLOW_NONE
534 Access is off. Clients get -PERM when trying to create nodes in
535 debugfs tree and debugfs is not registered as a filesystem.
536 Client can then back-off or continue without debugfs access.
540 source "lib/Kconfig.kgdb"
541 source "lib/Kconfig.ubsan"
542 source "lib/Kconfig.kcsan"
547 bool "Kernel debugging"
549 Say Y here if you are developing drivers or trying to debug and
550 identify kernel problems.
553 bool "Miscellaneous debug code"
555 depends on DEBUG_KERNEL
557 Say Y here if you need to enable miscellaneous debug code that should
558 be under a more specific debug option but isn't.
561 menu "Memory Debugging"
563 source "mm/Kconfig.debug"
566 bool "Debug object operations"
567 depends on DEBUG_KERNEL
569 If you say Y here, additional code will be inserted into the
570 kernel to track the life time of various objects and validate
571 the operations on those objects.
573 config DEBUG_OBJECTS_SELFTEST
574 bool "Debug objects selftest"
575 depends on DEBUG_OBJECTS
577 This enables the selftest of the object debug code.
579 config DEBUG_OBJECTS_FREE
580 bool "Debug objects in freed memory"
581 depends on DEBUG_OBJECTS
583 This enables checks whether a k/v free operation frees an area
584 which contains an object which has not been deactivated
585 properly. This can make kmalloc/kfree-intensive workloads
588 config DEBUG_OBJECTS_TIMERS
589 bool "Debug timer objects"
590 depends on DEBUG_OBJECTS
592 If you say Y here, additional code will be inserted into the
593 timer routines to track the life time of timer objects and
594 validate the timer operations.
596 config DEBUG_OBJECTS_WORK
597 bool "Debug work objects"
598 depends on DEBUG_OBJECTS
600 If you say Y here, additional code will be inserted into the
601 work queue routines to track the life time of work objects and
602 validate the work operations.
604 config DEBUG_OBJECTS_RCU_HEAD
605 bool "Debug RCU callbacks objects"
606 depends on DEBUG_OBJECTS
608 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
610 config DEBUG_OBJECTS_PERCPU_COUNTER
611 bool "Debug percpu counter objects"
612 depends on DEBUG_OBJECTS
614 If you say Y here, additional code will be inserted into the
615 percpu counter routines to track the life time of percpu counter
616 objects and validate the percpu counter operations.
618 config DEBUG_OBJECTS_ENABLE_DEFAULT
619 int "debug_objects bootup default value (0-1)"
622 depends on DEBUG_OBJECTS
624 Debug objects boot parameter default value
627 bool "Debug slab memory allocations"
628 depends on DEBUG_KERNEL && SLAB
630 Say Y here to have the kernel do limited verification on memory
631 allocation as well as poisoning memory on free to catch use of freed
632 memory. This can make kmalloc/kfree-intensive workloads much slower.
635 bool "SLUB debugging on by default"
636 depends on SLUB && SLUB_DEBUG
639 Boot with debugging on by default. SLUB boots by default with
640 the runtime debug capabilities switched off. Enabling this is
641 equivalent to specifying the "slub_debug" parameter on boot.
642 There is no support for more fine grained debug control like
643 possible with slub_debug=xxx. SLUB debugging may be switched
644 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
649 bool "Enable SLUB performance statistics"
650 depends on SLUB && SYSFS
652 SLUB statistics are useful to debug SLUBs allocation behavior in
653 order find ways to optimize the allocator. This should never be
654 enabled for production use since keeping statistics slows down
655 the allocator by a few percentage points. The slabinfo command
656 supports the determination of the most active slabs to figure
657 out which slabs are relevant to a particular load.
658 Try running: slabinfo -DA
660 config HAVE_DEBUG_KMEMLEAK
663 config DEBUG_KMEMLEAK
664 bool "Kernel memory leak detector"
665 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
667 select STACKTRACE if STACKTRACE_SUPPORT
671 Say Y here if you want to enable the memory leak
672 detector. The memory allocation/freeing is traced in a way
673 similar to the Boehm's conservative garbage collector, the
674 difference being that the orphan objects are not freed but
675 only shown in /sys/kernel/debug/kmemleak. Enabling this
676 feature will introduce an overhead to memory
677 allocations. See Documentation/dev-tools/kmemleak.rst for more
680 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
681 of finding leaks due to the slab objects poisoning.
683 In order to access the kmemleak file, debugfs needs to be
684 mounted (usually at /sys/kernel/debug).
686 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
687 int "Kmemleak memory pool size"
688 depends on DEBUG_KMEMLEAK
692 Kmemleak must track all the memory allocations to avoid
693 reporting false positives. Since memory may be allocated or
694 freed before kmemleak is fully initialised, use a static pool
695 of metadata objects to track such callbacks. After kmemleak is
696 fully initialised, this memory pool acts as an emergency one
697 if slab allocations fail.
699 config DEBUG_KMEMLEAK_TEST
700 tristate "Simple test for the kernel memory leak detector"
701 depends on DEBUG_KMEMLEAK && m
703 This option enables a module that explicitly leaks memory.
707 config DEBUG_KMEMLEAK_DEFAULT_OFF
708 bool "Default kmemleak to off"
709 depends on DEBUG_KMEMLEAK
711 Say Y here to disable kmemleak by default. It can then be enabled
712 on the command line via kmemleak=on.
714 config DEBUG_KMEMLEAK_AUTO_SCAN
715 bool "Enable kmemleak auto scan thread on boot up"
717 depends on DEBUG_KMEMLEAK
719 Depending on the cpu, kmemleak scan may be cpu intensive and can
720 stall user tasks at times. This option enables/disables automatic
721 kmemleak scan at boot up.
723 Say N here to disable kmemleak auto scan thread to stop automatic
724 scanning. Disabling this option disables automatic reporting of
729 config DEBUG_STACK_USAGE
730 bool "Stack utilization instrumentation"
731 depends on DEBUG_KERNEL && !IA64
733 Enables the display of the minimum amount of free stack which each
734 task has ever had available in the sysrq-T and sysrq-P debug output.
736 This option will slow down process creation somewhat.
738 config SCHED_STACK_END_CHECK
739 bool "Detect stack corruption on calls to schedule()"
740 depends on DEBUG_KERNEL
743 This option checks for a stack overrun on calls to schedule().
744 If the stack end location is found to be over written always panic as
745 the content of the corrupted region can no longer be trusted.
746 This is to ensure no erroneous behaviour occurs which could result in
747 data corruption or a sporadic crash at a later stage once the region
748 is examined. The runtime overhead introduced is minimal.
750 config ARCH_HAS_DEBUG_VM_PGTABLE
753 An architecture should select this when it can successfully
754 build and run DEBUG_VM_PGTABLE.
758 depends on DEBUG_KERNEL
760 Enable this to turn on extended checks in the virtual-memory system
761 that may impact performance.
765 config DEBUG_VM_VMACACHE
766 bool "Debug VMA caching"
769 Enable this to turn on VMA caching debug information. Doing so
770 can cause significant overhead, so only enable it in non-production
776 bool "Debug VM red-black trees"
779 Enable VM red-black tree debugging information and extra validations.
783 config DEBUG_VM_PGFLAGS
784 bool "Debug page-flags operations"
787 Enables extra validation on page flags operations.
791 config DEBUG_VM_PGTABLE
792 bool "Debug arch page table for semantics compliance"
794 depends on ARCH_HAS_DEBUG_VM_PGTABLE
795 default y if DEBUG_VM
797 This option provides a debug method which can be used to test
798 architecture page table helper functions on various platforms in
799 verifying if they comply with expected generic MM semantics. This
800 will help architecture code in making sure that any changes or
801 new additions of these helpers still conform to expected
802 semantics of the generic MM. Platforms will have to opt in for
803 this through ARCH_HAS_DEBUG_VM_PGTABLE.
807 config ARCH_HAS_DEBUG_VIRTUAL
811 bool "Debug VM translations"
812 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
814 Enable some costly sanity checks in virtual to page code. This can
815 catch mistakes with virt_to_page() and friends.
819 config DEBUG_NOMMU_REGIONS
820 bool "Debug the global anon/private NOMMU mapping region tree"
821 depends on DEBUG_KERNEL && !MMU
823 This option causes the global tree of anonymous and private mapping
824 regions to be regularly checked for invalid topology.
826 config DEBUG_MEMORY_INIT
827 bool "Debug memory initialisation" if EXPERT
830 Enable this for additional checks during memory initialisation.
831 The sanity checks verify aspects of the VM such as the memory model
832 and other information provided by the architecture. Verbose
833 information will be printed at KERN_DEBUG loglevel depending
834 on the mminit_loglevel= command-line option.
838 config MEMORY_NOTIFIER_ERROR_INJECT
839 tristate "Memory hotplug notifier error injection module"
840 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
842 This option provides the ability to inject artificial errors to
843 memory hotplug notifier chain callbacks. It is controlled through
844 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
846 If the notifier call chain should be failed with some events
847 notified, write the error code to "actions/<notifier event>/error".
849 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
851 # cd /sys/kernel/debug/notifier-error-inject/memory
852 # echo -12 > actions/MEM_GOING_OFFLINE/error
853 # echo offline > /sys/devices/system/memory/memoryXXX/state
854 bash: echo: write error: Cannot allocate memory
856 To compile this code as a module, choose M here: the module will
857 be called memory-notifier-error-inject.
861 config DEBUG_PER_CPU_MAPS
862 bool "Debug access to per_cpu maps"
863 depends on DEBUG_KERNEL
866 Say Y to verify that the per_cpu map being accessed has
867 been set up. This adds a fair amount of code to kernel memory
868 and decreases performance.
872 config DEBUG_KMAP_LOCAL
873 bool "Debug kmap_local temporary mappings"
874 depends on DEBUG_KERNEL && KMAP_LOCAL
876 This option enables additional error checking for the kmap_local
877 infrastructure. Disable for production use.
879 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
882 config DEBUG_KMAP_LOCAL_FORCE_MAP
883 bool "Enforce kmap_local temporary mappings"
884 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
886 select DEBUG_KMAP_LOCAL
888 This option enforces temporary mappings through the kmap_local
889 mechanism for non-highmem pages and on non-highmem systems.
890 Disable this for production systems!
893 bool "Highmem debugging"
894 depends on DEBUG_KERNEL && HIGHMEM
895 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
896 select DEBUG_KMAP_LOCAL
898 This option enables additional error checking for high memory
899 systems. Disable for production systems.
901 config HAVE_DEBUG_STACKOVERFLOW
904 config DEBUG_STACKOVERFLOW
905 bool "Check for stack overflows"
906 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
908 Say Y here if you want to check for overflows of kernel, IRQ
909 and exception stacks (if your architecture uses them). This
910 option will show detailed messages if free stack space drops
911 below a certain limit.
913 These kinds of bugs usually occur when call-chains in the
914 kernel get too deep, especially when interrupts are
917 Use this in cases where you see apparently random memory
918 corruption, especially if it appears in 'struct thread_info'
920 If in doubt, say "N".
922 source "lib/Kconfig.kasan"
924 endmenu # "Memory Debugging"
927 bool "Debug shared IRQ handlers"
928 depends on DEBUG_KERNEL
930 Enable this to generate a spurious interrupt just before a shared
931 interrupt handler is deregistered (generating one when registering
932 is currently disabled). Drivers need to handle this correctly. Some
933 don't and need to be caught.
935 menu "Debug Oops, Lockups and Hangs"
940 Say Y here to enable the kernel to panic when it oopses. This
941 has the same effect as setting oops=panic on the kernel command
944 This feature is useful to ensure that the kernel does not do
945 anything erroneous after an oops which could result in data
946 corruption or other issues.
950 config PANIC_ON_OOPS_VALUE
953 default 0 if !PANIC_ON_OOPS
954 default 1 if PANIC_ON_OOPS
960 Set the timeout value (in seconds) until a reboot occurs when
961 the kernel panics. If n = 0, then we wait forever. A timeout
962 value n > 0 will wait n seconds before rebooting, while a timeout
963 value n < 0 will reboot immediately.
965 config LOCKUP_DETECTOR
968 config SOFTLOCKUP_DETECTOR
969 bool "Detect Soft Lockups"
970 depends on DEBUG_KERNEL && !S390
971 select LOCKUP_DETECTOR
973 Say Y here to enable the kernel to act as a watchdog to detect
976 Softlockups are bugs that cause the kernel to loop in kernel
977 mode for more than 20 seconds, without giving other tasks a
978 chance to run. The current stack trace is displayed upon
979 detection and the system will stay locked up.
981 config BOOTPARAM_SOFTLOCKUP_PANIC
982 bool "Panic (Reboot) On Soft Lockups"
983 depends on SOFTLOCKUP_DETECTOR
985 Say Y here to enable the kernel to panic on "soft lockups",
986 which are bugs that cause the kernel to loop in kernel
987 mode for more than 20 seconds (configurable using the watchdog_thresh
988 sysctl), without giving other tasks a chance to run.
990 The panic can be used in combination with panic_timeout,
991 to cause the system to reboot automatically after a
992 lockup has been detected. This feature is useful for
993 high-availability systems that have uptime guarantees and
994 where a lockup must be resolved ASAP.
998 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
1000 depends on SOFTLOCKUP_DETECTOR
1002 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
1003 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
1005 config HARDLOCKUP_DETECTOR_PERF
1007 select SOFTLOCKUP_DETECTOR
1010 # Enables a timestamp based low pass filter to compensate for perf based
1011 # hard lockup detection which runs too fast due to turbo modes.
1013 config HARDLOCKUP_CHECK_TIMESTAMP
1017 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1018 # lockup detector rather than the perf based detector.
1020 config HARDLOCKUP_DETECTOR
1021 bool "Detect Hard Lockups"
1022 depends on DEBUG_KERNEL && !S390
1023 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1024 select LOCKUP_DETECTOR
1025 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1026 select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH
1028 Say Y here to enable the kernel to act as a watchdog to detect
1031 Hardlockups are bugs that cause the CPU to loop in kernel mode
1032 for more than 10 seconds, without letting other interrupts have a
1033 chance to run. The current stack trace is displayed upon detection
1034 and the system will stay locked up.
1036 config BOOTPARAM_HARDLOCKUP_PANIC
1037 bool "Panic (Reboot) On Hard Lockups"
1038 depends on HARDLOCKUP_DETECTOR
1040 Say Y here to enable the kernel to panic on "hard lockups",
1041 which are bugs that cause the kernel to loop in kernel
1042 mode with interrupts disabled for more than 10 seconds (configurable
1043 using the watchdog_thresh sysctl).
1047 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
1049 depends on HARDLOCKUP_DETECTOR
1051 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
1052 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
1054 config DETECT_HUNG_TASK
1055 bool "Detect Hung Tasks"
1056 depends on DEBUG_KERNEL
1057 default SOFTLOCKUP_DETECTOR
1059 Say Y here to enable the kernel to detect "hung tasks",
1060 which are bugs that cause the task to be stuck in
1061 uninterruptible "D" state indefinitely.
1063 When a hung task is detected, the kernel will print the
1064 current stack trace (which you should report), but the
1065 task will stay in uninterruptible state. If lockdep is
1066 enabled then all held locks will also be reported. This
1067 feature has negligible overhead.
1069 config DEFAULT_HUNG_TASK_TIMEOUT
1070 int "Default timeout for hung task detection (in seconds)"
1071 depends on DETECT_HUNG_TASK
1074 This option controls the default timeout (in seconds) used
1075 to determine when a task has become non-responsive and should
1078 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1079 sysctl or by writing a value to
1080 /proc/sys/kernel/hung_task_timeout_secs.
1082 A timeout of 0 disables the check. The default is two minutes.
1083 Keeping the default should be fine in most cases.
1085 config BOOTPARAM_HUNG_TASK_PANIC
1086 bool "Panic (Reboot) On Hung Tasks"
1087 depends on DETECT_HUNG_TASK
1089 Say Y here to enable the kernel to panic on "hung tasks",
1090 which are bugs that cause the kernel to leave a task stuck
1091 in uninterruptible "D" state.
1093 The panic can be used in combination with panic_timeout,
1094 to cause the system to reboot automatically after a
1095 hung task has been detected. This feature is useful for
1096 high-availability systems that have uptime guarantees and
1097 where a hung tasks must be resolved ASAP.
1101 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
1103 depends on DETECT_HUNG_TASK
1105 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
1106 default 1 if BOOTPARAM_HUNG_TASK_PANIC
1109 bool "Detect Workqueue Stalls"
1110 depends on DEBUG_KERNEL
1112 Say Y here to enable stall detection on workqueues. If a
1113 worker pool doesn't make forward progress on a pending work
1114 item for over a given amount of time, 30s by default, a
1115 warning message is printed along with dump of workqueue
1116 state. This can be configured through kernel parameter
1117 "workqueue.watchdog_thresh" and its sysfs counterpart.
1120 tristate "Test module to generate lockups"
1123 This builds the "test_lockup" module that helps to make sure
1124 that watchdogs and lockup detectors are working properly.
1126 Depending on module parameters it could emulate soft or hard
1127 lockup, "hung task", or locking arbitrary lock for a long time.
1128 Also it could generate series of lockups with cooling-down periods.
1132 endmenu # "Debug lockups and hangs"
1134 menu "Scheduler Debugging"
1137 bool "Collect scheduler debugging info"
1138 depends on DEBUG_KERNEL && PROC_FS
1141 If you say Y here, the /proc/sched_debug file will be provided
1142 that can help debug the scheduler. The runtime overhead of this
1150 bool "Collect scheduler statistics"
1151 depends on DEBUG_KERNEL && PROC_FS
1154 If you say Y here, additional code will be inserted into the
1155 scheduler and related routines to collect statistics about
1156 scheduler behavior and provide them in /proc/schedstat. These
1157 stats may be useful for both tuning and debugging the scheduler
1158 If you aren't debugging the scheduler or trying to tune a specific
1159 application, you can say N to avoid the very slight overhead
1164 config DEBUG_TIMEKEEPING
1165 bool "Enable extra timekeeping sanity checking"
1167 This option will enable additional timekeeping sanity checks
1168 which may be helpful when diagnosing issues where timekeeping
1169 problems are suspected.
1171 This may include checks in the timekeeping hotpaths, so this
1172 option may have a (very small) performance impact to some
1177 config DEBUG_PREEMPT
1178 bool "Debug preemptible kernel"
1179 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1182 If you say Y here then the kernel will use a debug variant of the
1183 commonly used smp_processor_id() function and will print warnings
1184 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1185 will detect preemption count underflows.
1187 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1189 config LOCK_DEBUGGING_SUPPORT
1191 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1194 config PROVE_LOCKING
1195 bool "Lock debugging: prove locking correctness"
1196 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1198 select DEBUG_SPINLOCK
1199 select DEBUG_MUTEXES
1200 select DEBUG_RT_MUTEXES if RT_MUTEXES
1202 select DEBUG_WW_MUTEX_SLOWPATH
1203 select DEBUG_LOCK_ALLOC
1204 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1205 select TRACE_IRQFLAGS
1208 This feature enables the kernel to prove that all locking
1209 that occurs in the kernel runtime is mathematically
1210 correct: that under no circumstance could an arbitrary (and
1211 not yet triggered) combination of observed locking
1212 sequences (on an arbitrary number of CPUs, running an
1213 arbitrary number of tasks and interrupt contexts) cause a
1216 In short, this feature enables the kernel to report locking
1217 related deadlocks before they actually occur.
1219 The proof does not depend on how hard and complex a
1220 deadlock scenario would be to trigger: how many
1221 participant CPUs, tasks and irq-contexts would be needed
1222 for it to trigger. The proof also does not depend on
1223 timing: if a race and a resulting deadlock is possible
1224 theoretically (no matter how unlikely the race scenario
1225 is), it will be proven so and will immediately be
1226 reported by the kernel (once the event is observed that
1227 makes the deadlock theoretically possible).
1229 If a deadlock is impossible (i.e. the locking rules, as
1230 observed by the kernel, are mathematically correct), the
1231 kernel reports nothing.
1233 NOTE: this feature can also be enabled for rwlocks, mutexes
1234 and rwsems - in which case all dependencies between these
1235 different locking variants are observed and mapped too, and
1236 the proof of observed correctness is also maintained for an
1237 arbitrary combination of these separate locking variants.
1239 For more details, see Documentation/locking/lockdep-design.rst.
1241 config PROVE_RAW_LOCK_NESTING
1242 bool "Enable raw_spinlock - spinlock nesting checks"
1243 depends on PROVE_LOCKING
1246 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1247 that the lock nesting rules for PREEMPT_RT enabled kernels are
1250 NOTE: There are known nesting problems. So if you enable this
1251 option expect lockdep splats until these problems have been fully
1252 addressed which is work in progress. This config switch allows to
1253 identify and analyze these problems. It will be removed and the
1254 check permanentely enabled once the main issues have been fixed.
1256 If unsure, select N.
1259 bool "Lock usage statistics"
1260 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1262 select DEBUG_SPINLOCK
1263 select DEBUG_MUTEXES
1264 select DEBUG_RT_MUTEXES if RT_MUTEXES
1265 select DEBUG_LOCK_ALLOC
1268 This feature enables tracking lock contention points
1270 For more details, see Documentation/locking/lockstat.rst
1272 This also enables lock events required by "perf lock",
1274 If you want to use "perf lock", you also need to turn on
1275 CONFIG_EVENT_TRACING.
1277 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1278 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1280 config DEBUG_RT_MUTEXES
1281 bool "RT Mutex debugging, deadlock detection"
1282 depends on DEBUG_KERNEL && RT_MUTEXES
1284 This allows rt mutex semantics violations and rt mutex related
1285 deadlocks (lockups) to be detected and reported automatically.
1287 config DEBUG_SPINLOCK
1288 bool "Spinlock and rw-lock debugging: basic checks"
1289 depends on DEBUG_KERNEL
1290 select UNINLINE_SPIN_UNLOCK
1292 Say Y here and build SMP to catch missing spinlock initialization
1293 and certain other kinds of spinlock errors commonly made. This is
1294 best used in conjunction with the NMI watchdog so that spinlock
1295 deadlocks are also debuggable.
1297 config DEBUG_MUTEXES
1298 bool "Mutex debugging: basic checks"
1299 depends on DEBUG_KERNEL
1301 This feature allows mutex semantics violations to be detected and
1304 config DEBUG_WW_MUTEX_SLOWPATH
1305 bool "Wait/wound mutex debugging: Slowpath testing"
1306 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1307 select DEBUG_LOCK_ALLOC
1308 select DEBUG_SPINLOCK
1309 select DEBUG_MUTEXES
1311 This feature enables slowpath testing for w/w mutex users by
1312 injecting additional -EDEADLK wound/backoff cases. Together with
1313 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1314 will test all possible w/w mutex interface abuse with the
1315 exception of simply not acquiring all the required locks.
1316 Note that this feature can introduce significant overhead, so
1317 it really should not be enabled in a production or distro kernel,
1318 even a debug kernel. If you are a driver writer, enable it. If
1319 you are a distro, do not.
1322 bool "RW Semaphore debugging: basic checks"
1323 depends on DEBUG_KERNEL
1325 This debugging feature allows mismatched rw semaphore locks
1326 and unlocks to be detected and reported.
1328 config DEBUG_LOCK_ALLOC
1329 bool "Lock debugging: detect incorrect freeing of live locks"
1330 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1331 select DEBUG_SPINLOCK
1332 select DEBUG_MUTEXES
1333 select DEBUG_RT_MUTEXES if RT_MUTEXES
1336 This feature will check whether any held lock (spinlock, rwlock,
1337 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1338 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1339 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1340 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1341 held during task exit.
1345 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1347 select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86
1351 config LOCKDEP_SMALL
1354 config DEBUG_LOCKDEP
1355 bool "Lock dependency engine debugging"
1356 depends on DEBUG_KERNEL && LOCKDEP
1358 If you say Y here, the lock dependency engine will do
1359 additional runtime checks to debug itself, at the price
1360 of more runtime overhead.
1362 config DEBUG_ATOMIC_SLEEP
1363 bool "Sleep inside atomic section checking"
1364 select PREEMPT_COUNT
1365 depends on DEBUG_KERNEL
1366 depends on !ARCH_NO_PREEMPT
1368 If you say Y here, various routines which may sleep will become very
1369 noisy if they are called inside atomic sections: when a spinlock is
1370 held, inside an rcu read side critical section, inside preempt disabled
1371 sections, inside an interrupt, etc...
1373 config DEBUG_LOCKING_API_SELFTESTS
1374 bool "Locking API boot-time self-tests"
1375 depends on DEBUG_KERNEL
1377 Say Y here if you want the kernel to run a short self-test during
1378 bootup. The self-test checks whether common types of locking bugs
1379 are detected by debugging mechanisms or not. (if you disable
1380 lock debugging then those bugs wont be detected of course.)
1381 The following locking APIs are covered: spinlocks, rwlocks,
1384 config LOCK_TORTURE_TEST
1385 tristate "torture tests for locking"
1386 depends on DEBUG_KERNEL
1389 This option provides a kernel module that runs torture tests
1390 on kernel locking primitives. The kernel module may be built
1391 after the fact on the running kernel to be tested, if desired.
1393 Say Y here if you want kernel locking-primitive torture tests
1394 to be built into the kernel.
1395 Say M if you want these torture tests to build as a module.
1396 Say N if you are unsure.
1398 config WW_MUTEX_SELFTEST
1399 tristate "Wait/wound mutex selftests"
1401 This option provides a kernel module that runs tests on the
1402 on the struct ww_mutex locking API.
1404 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1405 with this test harness.
1407 Say M if you want these self tests to build as a module.
1408 Say N if you are unsure.
1410 config SCF_TORTURE_TEST
1411 tristate "torture tests for smp_call_function*()"
1412 depends on DEBUG_KERNEL
1415 This option provides a kernel module that runs torture tests
1416 on the smp_call_function() family of primitives. The kernel
1417 module may be built after the fact on the running kernel to
1418 be tested, if desired.
1420 config CSD_LOCK_WAIT_DEBUG
1421 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1422 depends on DEBUG_KERNEL
1426 This option enables debug prints when CPUs are slow to respond
1427 to the smp_call_function*() IPI wrappers. These debug prints
1428 include the IPI handler function currently executing (if any)
1429 and relevant stack traces.
1431 endmenu # lock debugging
1433 config TRACE_IRQFLAGS
1434 depends on TRACE_IRQFLAGS_SUPPORT
1437 Enables hooks to interrupt enabling and disabling for
1438 either tracing or lock debugging.
1440 config TRACE_IRQFLAGS_NMI
1442 depends on TRACE_IRQFLAGS
1443 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1446 bool "Stack backtrace support"
1447 depends on STACKTRACE_SUPPORT
1449 This option causes the kernel to create a /proc/pid/stack for
1450 every process, showing its current stack trace.
1451 It is also used by various kernel debugging features that require
1452 stack trace generation.
1454 config WARN_ALL_UNSEEDED_RANDOM
1455 bool "Warn for all uses of unseeded randomness"
1458 Some parts of the kernel contain bugs relating to their use of
1459 cryptographically secure random numbers before it's actually possible
1460 to generate those numbers securely. This setting ensures that these
1461 flaws don't go unnoticed, by enabling a message, should this ever
1462 occur. This will allow people with obscure setups to know when things
1463 are going wrong, so that they might contact developers about fixing
1466 Unfortunately, on some models of some architectures getting
1467 a fully seeded CRNG is extremely difficult, and so this can
1468 result in dmesg getting spammed for a surprisingly long
1469 time. This is really bad from a security perspective, and
1470 so architecture maintainers really need to do what they can
1471 to get the CRNG seeded sooner after the system is booted.
1472 However, since users cannot do anything actionable to
1473 address this, by default the kernel will issue only a single
1474 warning for the first use of unseeded randomness.
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 select FRAME_POINTER if !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 || GENERIC_LIB_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
1810 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1812 config FAULT_INJECTION
1813 bool "Fault-injection framework"
1814 depends on DEBUG_KERNEL
1816 Provide fault-injection framework.
1817 For more details, see Documentation/fault-injection/.
1820 bool "Fault-injection capability for kmalloc"
1821 depends on FAULT_INJECTION
1822 depends on SLAB || SLUB
1824 Provide fault-injection capability for kmalloc.
1826 config FAIL_PAGE_ALLOC
1827 bool "Fault-injection capability for alloc_pages()"
1828 depends on FAULT_INJECTION
1830 Provide fault-injection capability for alloc_pages().
1832 config FAULT_INJECTION_USERCOPY
1833 bool "Fault injection capability for usercopy functions"
1834 depends on FAULT_INJECTION
1836 Provides fault-injection capability to inject failures
1837 in usercopy functions (copy_from_user(), get_user(), ...).
1839 config FAIL_MAKE_REQUEST
1840 bool "Fault-injection capability for disk IO"
1841 depends on FAULT_INJECTION && BLOCK
1843 Provide fault-injection capability for disk IO.
1845 config FAIL_IO_TIMEOUT
1846 bool "Fault-injection capability for faking disk interrupts"
1847 depends on FAULT_INJECTION && BLOCK
1849 Provide fault-injection capability on end IO handling. This
1850 will make the block layer "forget" an interrupt as configured,
1851 thus exercising the error handling.
1853 Only works with drivers that use the generic timeout handling,
1854 for others it wont do anything.
1857 bool "Fault-injection capability for futexes"
1859 depends on FAULT_INJECTION && FUTEX
1861 Provide fault-injection capability for futexes.
1863 config FAULT_INJECTION_DEBUG_FS
1864 bool "Debugfs entries for fault-injection capabilities"
1865 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1867 Enable configuration of fault-injection capabilities via debugfs.
1869 config FAIL_FUNCTION
1870 bool "Fault-injection capability for functions"
1871 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1873 Provide function-based fault-injection capability.
1874 This will allow you to override a specific function with a return
1875 with given return value. As a result, function caller will see
1876 an error value and have to handle it. This is useful to test the
1877 error handling in various subsystems.
1879 config FAIL_MMC_REQUEST
1880 bool "Fault-injection capability for MMC IO"
1881 depends on FAULT_INJECTION_DEBUG_FS && MMC
1883 Provide fault-injection capability for MMC IO.
1884 This will make the mmc core return data errors. This is
1885 useful to test the error handling in the mmc block device
1886 and to test how the mmc host driver handles retries from
1889 config FAULT_INJECTION_STACKTRACE_FILTER
1890 bool "stacktrace filter for fault-injection capabilities"
1891 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1894 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
1896 Provide stacktrace filter for fault-injection capabilities
1898 config ARCH_HAS_KCOV
1901 An architecture should select this when it can successfully
1902 build and run with CONFIG_KCOV. This typically requires
1903 disabling instrumentation for some early boot code.
1905 config CC_HAS_SANCOV_TRACE_PC
1906 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1910 bool "Code coverage for fuzzing"
1911 depends on ARCH_HAS_KCOV
1912 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1914 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1916 KCOV exposes kernel code coverage information in a form suitable
1917 for coverage-guided fuzzing (randomized testing).
1919 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1920 different machines and across reboots. If you need stable PC values,
1921 disable RANDOMIZE_BASE.
1923 For more details, see Documentation/dev-tools/kcov.rst.
1925 config KCOV_ENABLE_COMPARISONS
1926 bool "Enable comparison operands collection by KCOV"
1928 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
1930 KCOV also exposes operands of every comparison in the instrumented
1931 code along with operand sizes and PCs of the comparison instructions.
1932 These operands can be used by fuzzing engines to improve the quality
1933 of fuzzing coverage.
1935 config KCOV_INSTRUMENT_ALL
1936 bool "Instrument all code by default"
1940 If you are doing generic system call fuzzing (like e.g. syzkaller),
1941 then you will want to instrument the whole kernel and you should
1942 say y here. If you are doing more targeted fuzzing (like e.g.
1943 filesystem fuzzing with AFL) then you will want to enable coverage
1944 for more specific subsets of files, and should say n here.
1946 config KCOV_IRQ_AREA_SIZE
1947 hex "Size of interrupt coverage collection area in words"
1951 KCOV uses preallocated per-cpu areas to collect coverage from
1952 soft interrupts. This specifies the size of those areas in the
1953 number of unsigned long words.
1955 menuconfig RUNTIME_TESTING_MENU
1956 bool "Runtime Testing"
1959 if RUNTIME_TESTING_MENU
1962 tristate "Linux Kernel Dump Test Tool Module"
1965 This module enables testing of the different dumping mechanisms by
1966 inducing system failures at predefined crash points.
1967 If you don't need it: say N
1968 Choose M here to compile this code as a module. The module will be
1971 Documentation on how to use the module can be found in
1972 Documentation/fault-injection/provoke-crashes.rst
1974 config TEST_LIST_SORT
1975 tristate "Linked list sorting test"
1976 depends on DEBUG_KERNEL || m
1978 Enable this to turn on 'list_sort()' function test. This test is
1979 executed only once during system boot (so affects only boot time),
1980 or at module load time.
1984 config TEST_MIN_HEAP
1985 tristate "Min heap test"
1986 depends on DEBUG_KERNEL || m
1988 Enable this to turn on min heap function tests. This test is
1989 executed only once during system boot (so affects only boot time),
1990 or at module load time.
1995 tristate "Array-based sort test"
1996 depends on DEBUG_KERNEL || m
1998 This option enables the self-test function of 'sort()' at boot,
1999 or at module load time.
2003 config KPROBES_SANITY_TEST
2004 bool "Kprobes sanity tests"
2005 depends on DEBUG_KERNEL
2008 This option provides for testing basic kprobes functionality on
2009 boot. Samples of kprobe and kretprobe are inserted and
2010 verified for functionality.
2012 Say N if you are unsure.
2014 config BACKTRACE_SELF_TEST
2015 tristate "Self test for the backtrace code"
2016 depends on DEBUG_KERNEL
2018 This option provides a kernel module that can be used to test
2019 the kernel stack backtrace code. This option is not useful
2020 for distributions or general kernels, but only for kernel
2021 developers working on architecture code.
2023 Note that if you want to also test saved backtraces, you will
2024 have to enable STACKTRACE as well.
2026 Say N if you are unsure.
2029 tristate "Red-Black tree test"
2030 depends on DEBUG_KERNEL
2032 A benchmark measuring the performance of the rbtree library.
2033 Also includes rbtree invariant checks.
2035 config REED_SOLOMON_TEST
2036 tristate "Reed-Solomon library test"
2037 depends on DEBUG_KERNEL || m
2039 select REED_SOLOMON_ENC16
2040 select REED_SOLOMON_DEC16
2042 This option enables the self-test function of rslib at boot,
2043 or at module load time.
2047 config INTERVAL_TREE_TEST
2048 tristate "Interval tree test"
2049 depends on DEBUG_KERNEL
2050 select INTERVAL_TREE
2052 A benchmark measuring the performance of the interval tree library
2055 tristate "Per cpu operations test"
2056 depends on m && DEBUG_KERNEL
2058 Enable this option to build test module which validates per-cpu
2063 config ATOMIC64_SELFTEST
2064 tristate "Perform an atomic64_t self-test"
2066 Enable this option to test the atomic64_t functions at boot or
2067 at module load time.
2071 config ASYNC_RAID6_TEST
2072 tristate "Self test for hardware accelerated raid6 recovery"
2073 depends on ASYNC_RAID6_RECOV
2076 This is a one-shot self test that permutes through the
2077 recovery of all the possible two disk failure scenarios for a
2078 N-disk array. Recovery is performed with the asynchronous
2079 raid6 recovery routines, and will optionally use an offload
2080 engine if one is available.
2085 tristate "Test functions located in the hexdump module at runtime"
2087 config TEST_STRING_HELPERS
2088 tristate "Test functions located in the string_helpers module at runtime"
2091 tristate "Test strscpy*() family of functions at runtime"
2094 tristate "Test kstrto*() family of functions at runtime"
2097 tristate "Test printf() family of functions at runtime"
2100 tristate "Test bitmap_*() family of functions at runtime"
2102 Enable this option to test the bitmap functions at boot.
2107 tristate "Test functions located in the uuid module at runtime"
2110 tristate "Test the XArray code at runtime"
2112 config TEST_OVERFLOW
2113 tristate "Test check_*_overflow() functions at runtime"
2115 config TEST_RHASHTABLE
2116 tristate "Perform selftest on resizable hash table"
2118 Enable this option to test the rhashtable functions at boot.
2123 tristate "Perform selftest on hash functions"
2125 Enable this option to test the kernel's integer (<linux/hash.h>),
2126 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
2127 hash functions on boot (or module load).
2129 This is intended to help people writing architecture-specific
2130 optimized versions. If unsure, say N.
2133 tristate "Perform selftest on IDA functions"
2136 tristate "Perform selftest on priority array manager"
2139 Enable this option to test priority array manager on boot
2144 config TEST_IRQ_TIMINGS
2145 bool "IRQ timings selftest"
2146 depends on IRQ_TIMINGS
2148 Enable this option to test the irq timings code on boot.
2153 tristate "Test module loading with 'hello world' module"
2156 This builds the "test_module" module that emits "Hello, world"
2157 on printk when loaded. It is designed to be used for basic
2158 evaluation of the module loading subsystem (for example when
2159 validating module verification). It lacks any extra dependencies,
2160 and will not normally be loaded by the system unless explicitly
2166 tristate "Test module for compilation of bitops operations"
2169 This builds the "test_bitops" module that is much like the
2170 TEST_LKM module except that it does a basic exercise of the
2171 set/clear_bit macros and get_count_order/long to make sure there are
2172 no compiler warnings from C=1 sparse checker or -Wextra
2173 compilations. It has no dependencies and doesn't run or load unless
2174 explicitly requested by name. for example: modprobe test_bitops.
2179 tristate "Test module for stress/performance analysis of vmalloc allocator"
2184 This builds the "test_vmalloc" module that should be used for
2185 stress and performance analysis. So, any new change for vmalloc
2186 subsystem can be evaluated from performance and stability point
2191 config TEST_USER_COPY
2192 tristate "Test user/kernel boundary protections"
2195 This builds the "test_user_copy" module that runs sanity checks
2196 on the copy_to/from_user infrastructure, making sure basic
2197 user/kernel boundary testing is working. If it fails to load,
2198 a regression has been detected in the user/kernel memory boundary
2204 tristate "Test BPF filter functionality"
2207 This builds the "test_bpf" module that runs various test vectors
2208 against the BPF interpreter or BPF JIT compiler depending on the
2209 current setting. This is in particular useful for BPF JIT compiler
2210 development, but also to run regression tests against changes in
2211 the interpreter code. It also enables test stubs for eBPF maps and
2212 verifier used by user space verifier testsuite.
2216 config TEST_BLACKHOLE_DEV
2217 tristate "Test blackhole netdev functionality"
2220 This builds the "test_blackhole_dev" module that validates the
2221 data path through this blackhole netdev.
2225 config FIND_BIT_BENCHMARK
2226 tristate "Test find_bit functions"
2228 This builds the "test_find_bit" module that measure find_*_bit()
2229 functions performance.
2233 config TEST_FIRMWARE
2234 tristate "Test firmware loading via userspace interface"
2235 depends on FW_LOADER
2237 This builds the "test_firmware" module that creates a userspace
2238 interface for testing firmware loading. This can be used to
2239 control the triggering of firmware loading without needing an
2240 actual firmware-using device. The contents can be rechecked by
2246 tristate "sysctl test driver"
2247 depends on PROC_SYSCTL
2249 This builds the "test_sysctl" module. This driver enables to test the
2250 proc sysctl interfaces available to drivers safely without affecting
2251 production knobs which might alter system functionality.
2255 config BITFIELD_KUNIT
2256 tristate "KUnit test bitfield functions at runtime"
2259 Enable this option to test the bitfield functions at boot.
2261 KUnit tests run during boot and output the results to the debug log
2262 in TAP format (http://testanything.org/). Only useful for kernel devs
2263 running the KUnit test harness, and not intended for inclusion into a
2266 For more information on KUnit and unit tests in general please refer
2267 to the KUnit documentation in Documentation/dev-tools/kunit/.
2271 config RESOURCE_KUNIT_TEST
2272 tristate "KUnit test for resource API"
2275 This builds the resource API unit test.
2276 Tests the logic of API provided by resource.c and ioport.h.
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 SYSCTL_KUNIT_TEST
2283 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2285 default KUNIT_ALL_TESTS
2287 This builds the proc sysctl unit test, which runs on boot.
2288 Tests the API contract and implementation correctness of sysctl.
2289 For more information on KUnit and unit tests in general please refer
2290 to the KUnit documentation in Documentation/dev-tools/kunit/.
2294 config LIST_KUNIT_TEST
2295 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2297 default KUNIT_ALL_TESTS
2299 This builds the linked list KUnit test suite.
2300 It tests that the API and basic functionality of the list_head type
2301 and associated macros.
2303 KUnit tests run during boot and output the results to the debug log
2304 in TAP format (https://testanything.org/). Only useful for kernel devs
2305 running the KUnit test harness, and not intended for inclusion into a
2308 For more information on KUnit and unit tests in general please refer
2309 to the KUnit documentation in Documentation/dev-tools/kunit/.
2313 config LINEAR_RANGES_TEST
2314 tristate "KUnit test for linear_ranges"
2316 select LINEAR_RANGES
2318 This builds the linear_ranges unit test, which runs on boot.
2319 Tests the linear_ranges logic correctness.
2320 For more information on KUnit and unit tests in general please refer
2321 to the KUnit documentation in Documentation/dev-tools/kunit/.
2325 config CMDLINE_KUNIT_TEST
2326 tristate "KUnit test for cmdline API"
2329 This builds the cmdline API unit test.
2330 Tests the logic of API provided by cmdline.c.
2331 For more information on KUnit and unit tests in general please refer
2332 to the KUnit documentation in Documentation/dev-tools/kunit/.
2337 tristate "KUnit test for bits.h"
2340 This builds the bits unit test.
2341 Tests the logic of macros defined in bits.h.
2342 For more information on KUnit and unit tests in general please refer
2343 to the KUnit documentation in Documentation/dev-tools/kunit/.
2348 tristate "udelay test driver"
2350 This builds the "udelay_test" module that helps to make sure
2351 that udelay() is working properly.
2355 config TEST_STATIC_KEYS
2356 tristate "Test static keys"
2359 Test the static key interfaces.
2364 tristate "kmod stress tester"
2366 depends on NETDEVICES && NET_CORE && INET # for TUN
2373 Test the kernel's module loading mechanism: kmod. kmod implements
2374 support to load modules using the Linux kernel's usermode helper.
2375 This test provides a series of tests against kmod.
2377 Although technically you can either build test_kmod as a module or
2378 into the kernel we disallow building it into the kernel since
2379 it stress tests request_module() and this will very likely cause
2380 some issues by taking over precious threads available from other
2381 module load requests, ultimately this could be fatal.
2385 tools/testing/selftests/kmod/kmod.sh --help
2389 config TEST_DEBUG_VIRTUAL
2390 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2391 depends on DEBUG_VIRTUAL
2393 Test the kernel's ability to detect incorrect calls to
2394 virt_to_phys() done against the non-linear part of the
2395 kernel's virtual address map.
2399 config TEST_MEMCAT_P
2400 tristate "Test memcat_p() helper function"
2402 Test the memcat_p() helper for correctly merging two
2403 pointer arrays together.
2407 config TEST_LIVEPATCH
2408 tristate "Test livepatching"
2410 depends on DYNAMIC_DEBUG
2411 depends on LIVEPATCH
2414 Test kernel livepatching features for correctness. The tests will
2415 load test modules that will be livepatched in various scenarios.
2417 To run all the livepatching tests:
2419 make -C tools/testing/selftests TARGETS=livepatch run_tests
2421 Alternatively, individual tests may be invoked:
2423 tools/testing/selftests/livepatch/test-callbacks.sh
2424 tools/testing/selftests/livepatch/test-livepatch.sh
2425 tools/testing/selftests/livepatch/test-shadow-vars.sh
2430 tristate "Perform selftest on object aggreration manager"
2434 Enable this option to test object aggregation manager on boot
2438 config TEST_STACKINIT
2439 tristate "Test level of stack variable initialization"
2441 Test if the kernel is zero-initializing stack variables and
2442 padding. Coverage is controlled by compiler flags,
2443 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2444 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2449 tristate "Test heap/page initialization"
2451 Test if the kernel is zero-initializing heap and page allocations.
2452 This can be useful to test init_on_alloc and init_on_free features.
2457 tristate "Test HMM (Heterogeneous Memory Management)"
2458 depends on TRANSPARENT_HUGEPAGE
2459 depends on DEVICE_PRIVATE
2463 This is a pseudo device driver solely for testing HMM.
2464 Say M here if you want to build the HMM test module.
2465 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2469 config TEST_FREE_PAGES
2470 tristate "Test freeing pages"
2472 Test that a memory leak does not occur due to a race between
2473 freeing a block of pages and a speculative page reference.
2474 Loading this module is safe if your kernel has the bug fixed.
2475 If the bug is not fixed, it will leak gigabytes of memory and
2476 probably OOM your system.
2479 tristate "Test floating point operations in kernel space"
2480 depends on X86 && !KCOV_INSTRUMENT_ALL
2482 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2483 which will trigger a sequence of floating point operations. This is used
2484 for self-testing floating point control register setting in
2489 endif # RUNTIME_TESTING_MENU
2494 This option adds a kernel parameter 'memtest', which allows memtest
2496 memtest=0, mean disabled; -- default
2497 memtest=1, mean do 1 test pattern;
2499 memtest=17, mean do 17 test patterns.
2500 If you are unsure how to answer this question, answer N.
2504 config HYPERV_TESTING
2505 bool "Microsoft Hyper-V driver testing"
2507 depends on HYPERV && DEBUG_FS
2509 Select this option to enable Hyper-V vmbus testing.
2511 endmenu # "Kernel Testing and Coverage"
2513 source "Documentation/Kconfig"
2515 endmenu # Kernel hacking