1 # SPDX-License-Identifier: GPL-2.0-only
4 menu "printk and dmesg options"
7 bool "Show timing information on printks"
10 Selecting this option causes time stamps of the printk()
11 messages to be added to the output of the syslog() system
12 call and at the console.
14 The timestamp is always recorded internally, and exported
15 to /dev/kmsg. This flag just specifies if the timestamp should
16 be included, not that the timestamp is recorded.
18 The behavior is also controlled by the kernel command line
19 parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
22 bool "Show caller information on printks"
25 Selecting this option causes printk() to add a caller "thread id" (if
26 in task context) or a caller "processor id" (if not in task context)
29 This option is intended for environments where multiple threads
30 concurrently call printk() for many times, for it is difficult to
31 interpret without knowing where these lines (or sometimes individual
32 line which was divided into multiple lines due to race) came from.
34 Since toggling after boot makes the code racy, currently there is
35 no option to enable/disable at the kernel command line parameter or
38 config STACKTRACE_BUILD_ID
39 bool "Show build ID information in stacktraces"
42 Selecting this option adds build ID information for symbols in
43 stacktraces printed with the printk format '%p[SR]b'.
45 This option is intended for distros where debuginfo is not easily
46 accessible but can be downloaded given the build ID of the vmlinux or
47 kernel module where the function is located.
49 config CONSOLE_LOGLEVEL_DEFAULT
50 int "Default console loglevel (1-15)"
54 Default loglevel to determine what will be printed on the console.
56 Setting a default here is equivalent to passing in loglevel=<x> in
57 the kernel bootargs. loglevel=<x> continues to override whatever
58 value is specified here as well.
60 Note: This does not affect the log level of un-prefixed printk()
61 usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
64 config CONSOLE_LOGLEVEL_QUIET
65 int "quiet console loglevel (1-15)"
69 loglevel to use when "quiet" is passed on the kernel commandline.
71 When "quiet" is passed on the kernel commandline this loglevel
72 will be used as the loglevel. IOW passing "quiet" will be the
73 equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
75 config MESSAGE_LOGLEVEL_DEFAULT
76 int "Default message log level (1-7)"
80 Default log level for printk statements with no specified priority.
82 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
83 that are auditing their logs closely may want to set it to a lower
86 Note: This does not affect what message level gets printed on the console
87 by default. To change that, use loglevel=<x> in the kernel bootargs,
88 or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
90 config BOOT_PRINTK_DELAY
91 bool "Delay each boot printk message by N milliseconds"
92 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
94 This build option allows you to read kernel boot messages
95 by inserting a short delay after each one. The delay is
96 specified in milliseconds on the kernel command line,
99 It is likely that you would also need to use "lpj=M" to preset
100 the "loops per jiffie" value.
101 See a previous boot log for the "lpj" value to use for your
102 system, and then set "lpj=M" before setting "boot_delay=N".
103 NOTE: Using this option may adversely affect SMP systems.
104 I.e., processors other than the first one may not boot up.
105 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
106 what it believes to be lockup conditions.
109 bool "Enable dynamic printk() support"
112 depends on (DEBUG_FS || PROC_FS)
113 select DYNAMIC_DEBUG_CORE
116 Compiles debug level messages into the kernel, which would not
117 otherwise be available at runtime. These messages can then be
118 enabled/disabled based on various levels of scope - per source file,
119 function, module, format string, and line number. This mechanism
120 implicitly compiles in all pr_debug() and dev_dbg() calls, which
121 enlarges the kernel text size by about 2%.
123 If a source file is compiled with DEBUG flag set, any
124 pr_debug() calls in it are enabled by default, but can be
125 disabled at runtime as below. Note that DEBUG flag is
126 turned on by many CONFIG_*DEBUG* options.
130 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
131 which is contained in the 'debugfs' filesystem or procfs.
132 Thus, the debugfs or procfs filesystem must first be mounted before
133 making use of this feature.
134 We refer the control file as: <debugfs>/dynamic_debug/control. This
135 file contains a list of the debug statements that can be enabled. The
136 format for each line of the file is:
138 filename:lineno [module]function flags format
140 filename : source file of the debug statement
141 lineno : line number of the debug statement
142 module : module that contains the debug statement
143 function : function that contains the debug statement
144 flags : '=p' means the line is turned 'on' for printing
145 format : the format used for the debug statement
149 nullarbor:~ # cat <debugfs>/dynamic_debug/control
150 # filename:lineno [module]function flags format
151 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
152 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
153 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
157 // enable the message at line 1603 of file svcsock.c
158 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
159 <debugfs>/dynamic_debug/control
161 // enable all the messages in file svcsock.c
162 nullarbor:~ # echo -n 'file svcsock.c +p' >
163 <debugfs>/dynamic_debug/control
165 // enable all the messages in the NFS server module
166 nullarbor:~ # echo -n 'module nfsd +p' >
167 <debugfs>/dynamic_debug/control
169 // enable all 12 messages in the function svc_process()
170 nullarbor:~ # echo -n 'func svc_process +p' >
171 <debugfs>/dynamic_debug/control
173 // disable all 12 messages in the function svc_process()
174 nullarbor:~ # echo -n 'func svc_process -p' >
175 <debugfs>/dynamic_debug/control
177 See Documentation/admin-guide/dynamic-debug-howto.rst for additional
180 config DYNAMIC_DEBUG_CORE
181 bool "Enable core function of dynamic debug support"
183 depends on (DEBUG_FS || PROC_FS)
185 Enable core functional support of dynamic debug. It is useful
186 when you want to tie dynamic debug to your kernel modules with
187 DYNAMIC_DEBUG_MODULE defined for each of them, especially for
188 the case of embedded system where the kernel image size is
189 sensitive for people.
191 config SYMBOLIC_ERRNAME
192 bool "Support symbolic error names in printf"
195 If you say Y here, the kernel's printf implementation will
196 be able to print symbolic error names such as ENOSPC instead
197 of the number 28. It makes the kernel image slightly larger
198 (about 3KB), but can make the kernel logs easier to read.
200 config DEBUG_BUGVERBOSE
201 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
202 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
205 Say Y here to make BUG() panics output the file name and line number
206 of the BUG call as well as the EIP and oops trace. This aids
207 debugging but costs about 70-100K of memory.
209 endmenu # "printk and dmesg options"
211 menu "Compile-time checks and compiler options"
214 bool "Compile the kernel with debug info"
215 depends on DEBUG_KERNEL && !COMPILE_TEST
217 If you say Y here the resulting kernel image will include
218 debugging info resulting in a larger kernel image.
219 This adds debug symbols to the kernel and modules (gcc -g), and
220 is needed if you intend to use kernel crashdump or binary object
221 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
222 Say Y here only if you plan to debug the kernel.
228 config DEBUG_INFO_REDUCED
229 bool "Reduce debugging information"
231 If you say Y here gcc is instructed to generate less debugging
232 information for structure types. This means that tools that
233 need full debugging information (like kgdb or systemtap) won't
234 be happy. But if you merely need debugging information to
235 resolve line numbers there is no loss. Advantage is that
236 build directory object sizes shrink dramatically over a full
237 DEBUG_INFO build and compile times are reduced too.
238 Only works with newer gcc versions.
240 config DEBUG_INFO_COMPRESSED
241 bool "Compressed debugging information"
242 depends on $(cc-option,-gz=zlib)
243 depends on $(ld-option,--compress-debug-sections=zlib)
245 Compress the debug information using zlib. Requires GCC 5.0+ or Clang
246 5.0+, binutils 2.26+, and zlib.
248 Users of dpkg-deb via scripts/package/builddeb may find an increase in
249 size of their debug .deb packages with this config set, due to the
250 debug info being compressed with zlib, then the object files being
251 recompressed with a different compression scheme. But this is still
252 preferable to setting $KDEB_COMPRESS to "none" which would be even
255 config DEBUG_INFO_SPLIT
256 bool "Produce split debuginfo in .dwo files"
257 depends on $(cc-option,-gsplit-dwarf)
259 Generate debug info into separate .dwo files. This significantly
260 reduces the build directory size for builds with DEBUG_INFO,
261 because it stores the information only once on disk in .dwo
262 files instead of multiple times in object files and executables.
263 In addition the debug information is also compressed.
265 Requires recent gcc (4.7+) and recent gdb/binutils.
266 Any tool that packages or reads debug information would need
267 to know about the .dwo files and include them.
268 Incompatible with older versions of ccache.
271 prompt "DWARF version"
273 Which version of DWARF debug info to emit.
275 config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
276 bool "Rely on the toolchain's implicit default DWARF version"
278 The implicit default version of DWARF debug info produced by a
279 toolchain changes over time.
281 This can break consumers of the debug info that haven't upgraded to
282 support newer revisions, and prevent testing newer versions, but
283 those should be less common scenarios.
287 config DEBUG_INFO_DWARF4
288 bool "Generate DWARF Version 4 debuginfo"
290 Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+.
292 If you have consumers of DWARF debug info that are not ready for
293 newer revisions of DWARF, you may wish to choose this or have your
296 config DEBUG_INFO_DWARF5
297 bool "Generate DWARF Version 5 debuginfo"
298 depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)))
299 depends on !DEBUG_INFO_BTF || PAHOLE_VERSION >= 121
301 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
302 5.0+ accepts the -gdwarf-5 flag but only had partial support for some
303 draft features until 7.0), and gdb 8.0+.
305 Changes to the structure of debug info in Version 5 allow for around
306 15-18% savings in resulting image and debug info section sizes as
307 compared to DWARF Version 4. DWARF Version 5 standardizes previous
308 extensions such as accelerators for symbol indexing and the format
309 for fission (.dwo/.dwp) files. Users may not want to select this
310 config if they rely on tooling that has not yet been updated to
311 support DWARF Version 5.
313 endchoice # "DWARF version"
315 config DEBUG_INFO_BTF
316 bool "Generate BTF typeinfo"
317 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
318 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
319 depends on BPF_SYSCALL
321 Generate deduplicated BTF type information from DWARF debug info.
322 Turning this on expects presence of pahole tool, which will convert
323 DWARF type info into equivalent deduplicated BTF type info.
325 config PAHOLE_HAS_SPLIT_BTF
326 def_bool PAHOLE_VERSION >= 119
328 config PAHOLE_HAS_BTF_TAG
329 def_bool PAHOLE_VERSION >= 123
330 depends on CC_IS_CLANG
332 Decide whether pahole emits btf_tag attributes (btf_type_tag and
333 btf_decl_tag) or not. Currently only clang compiler implements
334 these attributes, so make the config depend on CC_IS_CLANG.
336 config DEBUG_INFO_BTF_MODULES
338 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
340 Generate compact split BTF type information for kernel modules.
343 bool "Provide GDB scripts for kernel debugging"
345 This creates the required links to GDB helper scripts in the
346 build directory. If you load vmlinux into gdb, the helper
347 scripts will be automatically imported by gdb as well, and
348 additional functions are available to analyze a Linux kernel
349 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
355 int "Warn for stack frames larger than"
357 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
358 default 2048 if PARISC
359 default 1536 if (!64BIT && XTENSA)
360 default 1024 if !64BIT
361 default 2048 if 64BIT
363 Tell gcc to warn at build time for stack frames larger than this.
364 Setting this too low will cause a lot of warnings.
365 Setting it to 0 disables the warning.
367 config STRIP_ASM_SYMS
368 bool "Strip assembler-generated symbols during link"
371 Strip internal assembler-generated symbols during a link (symbols
372 that look like '.Lxxx') so they don't pollute the output of
373 get_wchan() and suchlike.
376 bool "Generate readable assembler code"
377 depends on DEBUG_KERNEL
380 Disable some compiler optimizations that tend to generate human unreadable
381 assembler output. This may make the kernel slightly slower, but it helps
382 to keep kernel developers who have to stare a lot at assembler listings
385 config HEADERS_INSTALL
386 bool "Install uapi headers to usr/include"
389 This option will install uapi headers (headers exported to user-space)
390 into the usr/include directory for use during the kernel build.
391 This is unneeded for building the kernel itself, but needed for some
392 user-space program samples. It is also needed by some features such
393 as uapi header sanity checks.
395 config DEBUG_SECTION_MISMATCH
396 bool "Enable full Section mismatch analysis"
399 The section mismatch analysis checks if there are illegal
400 references from one section to another section.
401 During linktime or runtime, some sections are dropped;
402 any use of code/data previously in these sections would
403 most likely result in an oops.
404 In the code, functions and variables are annotated with
405 __init,, etc. (see the full list in include/linux/init.h),
406 which results in the code/data being placed in specific sections.
407 The section mismatch analysis is always performed after a full
408 kernel build, and enabling this option causes the following
409 additional step to occur:
410 - Add the option -fno-inline-functions-called-once to gcc commands.
411 When inlining a function annotated with __init in a non-init
412 function, we would lose the section information and thus
413 the analysis would not catch the illegal reference.
414 This option tells gcc to inline less (but it does result in
417 config SECTION_MISMATCH_WARN_ONLY
418 bool "Make section mismatch errors non-fatal"
421 If you say N here, the build process will fail if there are any
422 section mismatch, instead of just throwing warnings.
426 config DEBUG_FORCE_FUNCTION_ALIGN_64B
427 bool "Force all function address 64B aligned" if EXPERT
429 There are cases that a commit from one domain changes the function
430 address alignment of other domains, and cause magic performance
431 bump (regression or improvement). Enable this option will help to
432 verify if the bump is caused by function alignment changes, while
433 it will slightly increase the kernel size and affect icache usage.
435 It is mainly for debug and performance tuning use.
438 # Select this config option from the architecture Kconfig, if it
439 # is preferred to always offer frame pointers as a config
440 # option on the architecture (regardless of KERNEL_DEBUG):
442 config ARCH_WANT_FRAME_POINTERS
446 bool "Compile the kernel with frame pointers"
447 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
448 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
450 If you say Y here the resulting kernel image will be slightly
451 larger and slower, but it gives very useful debugging information
452 in case of kernel bugs. (precise oopses/stacktraces/warnings)
454 config STACK_VALIDATION
455 bool "Compile-time stack metadata validation"
456 depends on HAVE_STACK_VALIDATION
459 Add compile-time checks to validate stack metadata, including frame
460 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
461 that runtime stack traces are more reliable.
463 This is also a prerequisite for generation of ORC unwind data, which
464 is needed for CONFIG_UNWINDER_ORC.
466 For more information, see
467 tools/objtool/Documentation/stack-validation.txt.
469 config VMLINUX_VALIDATION
471 depends on STACK_VALIDATION && DEBUG_ENTRY
475 bool "Generate vmlinux.map file when linking"
478 Selecting this option will pass "-Map=vmlinux.map" to ld
479 when linking vmlinux. That file can be useful for verifying
480 and debugging magic section games, and for seeing which
481 pieces of code get eliminated with
482 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
484 config DEBUG_FORCE_WEAK_PER_CPU
485 bool "Force weak per-cpu definitions"
486 depends on DEBUG_KERNEL
488 s390 and alpha require percpu variables in modules to be
489 defined weak to work around addressing range issue which
490 puts the following two restrictions on percpu variable
493 1. percpu symbols must be unique whether static or not
494 2. percpu variables can't be defined inside a function
496 To ensure that generic code follows the above rules, this
497 option forces all percpu variables to be defined as weak.
499 endmenu # "Compiler options"
501 menu "Generic Kernel Debugging Instruments"
504 bool "Magic SysRq key"
507 If you say Y here, you will have some control over the system even
508 if the system crashes for example during kernel debugging (e.g., you
509 will be able to flush the buffer cache to disk, reboot the system
510 immediately or dump some status information). This is accomplished
511 by pressing various keys while holding SysRq (Alt+PrintScreen). It
512 also works on a serial console (on PC hardware at least), if you
513 send a BREAK and then within 5 seconds a command keypress. The
514 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
515 Don't say Y unless you really know what this hack does.
517 config MAGIC_SYSRQ_DEFAULT_ENABLE
518 hex "Enable magic SysRq key functions by default"
519 depends on MAGIC_SYSRQ
522 Specifies which SysRq key functions are enabled by default.
523 This may be set to 1 or 0 to enable or disable them all, or
524 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
526 config MAGIC_SYSRQ_SERIAL
527 bool "Enable magic SysRq key over serial"
528 depends on MAGIC_SYSRQ
531 Many embedded boards have a disconnected TTL level serial which can
532 generate some garbage that can lead to spurious false sysrq detects.
533 This option allows you to decide whether you want to enable the
536 config MAGIC_SYSRQ_SERIAL_SEQUENCE
537 string "Char sequence that enables magic SysRq over serial"
538 depends on MAGIC_SYSRQ_SERIAL
541 Specifies a sequence of characters that can follow BREAK to enable
542 SysRq on a serial console.
544 If unsure, leave an empty string and the option will not be enabled.
547 bool "Debug Filesystem"
549 debugfs is a virtual file system that kernel developers use to put
550 debugging files into. Enable this option to be able to read and
551 write to these files.
553 For detailed documentation on the debugfs API, see
554 Documentation/filesystems/.
559 prompt "Debugfs default access"
561 default DEBUG_FS_ALLOW_ALL
563 This selects the default access restrictions for debugfs.
564 It can be overridden with kernel command line option
565 debugfs=[on,no-mount,off]. The restrictions apply for API access
566 and filesystem registration.
568 config DEBUG_FS_ALLOW_ALL
571 No restrictions apply. Both API and filesystem registration
572 is on. This is the normal default operation.
574 config DEBUG_FS_DISALLOW_MOUNT
575 bool "Do not register debugfs as filesystem"
577 The API is open but filesystem is not loaded. Clients can still do
578 their work and read with debug tools that do not need
581 config DEBUG_FS_ALLOW_NONE
584 Access is off. Clients get -PERM when trying to create nodes in
585 debugfs tree and debugfs is not registered as a filesystem.
586 Client can then back-off or continue without debugfs access.
590 source "lib/Kconfig.kgdb"
591 source "lib/Kconfig.ubsan"
592 source "lib/Kconfig.kcsan"
597 bool "Kernel debugging"
599 Say Y here if you are developing drivers or trying to debug and
600 identify kernel problems.
603 bool "Miscellaneous debug code"
605 depends on DEBUG_KERNEL
607 Say Y here if you need to enable miscellaneous debug code that should
608 be under a more specific debug option but isn't.
610 menu "Networking Debugging"
612 source "net/Kconfig.debug"
614 endmenu # "Networking Debugging"
616 menu "Memory Debugging"
618 source "mm/Kconfig.debug"
621 bool "Debug object operations"
622 depends on DEBUG_KERNEL
624 If you say Y here, additional code will be inserted into the
625 kernel to track the life time of various objects and validate
626 the operations on those objects.
628 config DEBUG_OBJECTS_SELFTEST
629 bool "Debug objects selftest"
630 depends on DEBUG_OBJECTS
632 This enables the selftest of the object debug code.
634 config DEBUG_OBJECTS_FREE
635 bool "Debug objects in freed memory"
636 depends on DEBUG_OBJECTS
638 This enables checks whether a k/v free operation frees an area
639 which contains an object which has not been deactivated
640 properly. This can make kmalloc/kfree-intensive workloads
643 config DEBUG_OBJECTS_TIMERS
644 bool "Debug timer objects"
645 depends on DEBUG_OBJECTS
647 If you say Y here, additional code will be inserted into the
648 timer routines to track the life time of timer objects and
649 validate the timer operations.
651 config DEBUG_OBJECTS_WORK
652 bool "Debug work objects"
653 depends on DEBUG_OBJECTS
655 If you say Y here, additional code will be inserted into the
656 work queue routines to track the life time of work objects and
657 validate the work operations.
659 config DEBUG_OBJECTS_RCU_HEAD
660 bool "Debug RCU callbacks objects"
661 depends on DEBUG_OBJECTS
663 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
665 config DEBUG_OBJECTS_PERCPU_COUNTER
666 bool "Debug percpu counter objects"
667 depends on DEBUG_OBJECTS
669 If you say Y here, additional code will be inserted into the
670 percpu counter routines to track the life time of percpu counter
671 objects and validate the percpu counter operations.
673 config DEBUG_OBJECTS_ENABLE_DEFAULT
674 int "debug_objects bootup default value (0-1)"
677 depends on DEBUG_OBJECTS
679 Debug objects boot parameter default value
682 bool "Debug slab memory allocations"
683 depends on DEBUG_KERNEL && SLAB
685 Say Y here to have the kernel do limited verification on memory
686 allocation as well as poisoning memory on free to catch use of freed
687 memory. This can make kmalloc/kfree-intensive workloads much slower.
690 bool "SLUB debugging on by default"
691 depends on SLUB && SLUB_DEBUG
694 Boot with debugging on by default. SLUB boots by default with
695 the runtime debug capabilities switched off. Enabling this is
696 equivalent to specifying the "slub_debug" parameter on boot.
697 There is no support for more fine grained debug control like
698 possible with slub_debug=xxx. SLUB debugging may be switched
699 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
704 bool "Enable SLUB performance statistics"
705 depends on SLUB && SYSFS
707 SLUB statistics are useful to debug SLUBs allocation behavior in
708 order find ways to optimize the allocator. This should never be
709 enabled for production use since keeping statistics slows down
710 the allocator by a few percentage points. The slabinfo command
711 supports the determination of the most active slabs to figure
712 out which slabs are relevant to a particular load.
713 Try running: slabinfo -DA
715 config HAVE_DEBUG_KMEMLEAK
718 config DEBUG_KMEMLEAK
719 bool "Kernel memory leak detector"
720 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
722 select STACKTRACE if STACKTRACE_SUPPORT
726 Say Y here if you want to enable the memory leak
727 detector. The memory allocation/freeing is traced in a way
728 similar to the Boehm's conservative garbage collector, the
729 difference being that the orphan objects are not freed but
730 only shown in /sys/kernel/debug/kmemleak. Enabling this
731 feature will introduce an overhead to memory
732 allocations. See Documentation/dev-tools/kmemleak.rst for more
735 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
736 of finding leaks due to the slab objects poisoning.
738 In order to access the kmemleak file, debugfs needs to be
739 mounted (usually at /sys/kernel/debug).
741 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
742 int "Kmemleak memory pool size"
743 depends on DEBUG_KMEMLEAK
747 Kmemleak must track all the memory allocations to avoid
748 reporting false positives. Since memory may be allocated or
749 freed before kmemleak is fully initialised, use a static pool
750 of metadata objects to track such callbacks. After kmemleak is
751 fully initialised, this memory pool acts as an emergency one
752 if slab allocations fail.
754 config DEBUG_KMEMLEAK_TEST
755 tristate "Simple test for the kernel memory leak detector"
756 depends on DEBUG_KMEMLEAK && m
758 This option enables a module that explicitly leaks memory.
762 config DEBUG_KMEMLEAK_DEFAULT_OFF
763 bool "Default kmemleak to off"
764 depends on DEBUG_KMEMLEAK
766 Say Y here to disable kmemleak by default. It can then be enabled
767 on the command line via kmemleak=on.
769 config DEBUG_KMEMLEAK_AUTO_SCAN
770 bool "Enable kmemleak auto scan thread on boot up"
772 depends on DEBUG_KMEMLEAK
774 Depending on the cpu, kmemleak scan may be cpu intensive and can
775 stall user tasks at times. This option enables/disables automatic
776 kmemleak scan at boot up.
778 Say N here to disable kmemleak auto scan thread to stop automatic
779 scanning. Disabling this option disables automatic reporting of
784 config DEBUG_STACK_USAGE
785 bool "Stack utilization instrumentation"
786 depends on DEBUG_KERNEL && !IA64
788 Enables the display of the minimum amount of free stack which each
789 task has ever had available in the sysrq-T and sysrq-P debug output.
791 This option will slow down process creation somewhat.
793 config SCHED_STACK_END_CHECK
794 bool "Detect stack corruption on calls to schedule()"
795 depends on DEBUG_KERNEL
798 This option checks for a stack overrun on calls to schedule().
799 If the stack end location is found to be over written always panic as
800 the content of the corrupted region can no longer be trusted.
801 This is to ensure no erroneous behaviour occurs which could result in
802 data corruption or a sporadic crash at a later stage once the region
803 is examined. The runtime overhead introduced is minimal.
805 config ARCH_HAS_DEBUG_VM_PGTABLE
808 An architecture should select this when it can successfully
809 build and run DEBUG_VM_PGTABLE.
813 depends on DEBUG_KERNEL
815 Enable this to turn on extended checks in the virtual-memory system
816 that may impact performance.
820 config DEBUG_VM_VMACACHE
821 bool "Debug VMA caching"
824 Enable this to turn on VMA caching debug information. Doing so
825 can cause significant overhead, so only enable it in non-production
831 bool "Debug VM red-black trees"
834 Enable VM red-black tree debugging information and extra validations.
838 config DEBUG_VM_PGFLAGS
839 bool "Debug page-flags operations"
842 Enables extra validation on page flags operations.
846 config DEBUG_VM_PGTABLE
847 bool "Debug arch page table for semantics compliance"
849 depends on ARCH_HAS_DEBUG_VM_PGTABLE
850 default y if DEBUG_VM
852 This option provides a debug method which can be used to test
853 architecture page table helper functions on various platforms in
854 verifying if they comply with expected generic MM semantics. This
855 will help architecture code in making sure that any changes or
856 new additions of these helpers still conform to expected
857 semantics of the generic MM. Platforms will have to opt in for
858 this through ARCH_HAS_DEBUG_VM_PGTABLE.
862 config ARCH_HAS_DEBUG_VIRTUAL
866 bool "Debug VM translations"
867 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
869 Enable some costly sanity checks in virtual to page code. This can
870 catch mistakes with virt_to_page() and friends.
874 config DEBUG_NOMMU_REGIONS
875 bool "Debug the global anon/private NOMMU mapping region tree"
876 depends on DEBUG_KERNEL && !MMU
878 This option causes the global tree of anonymous and private mapping
879 regions to be regularly checked for invalid topology.
881 config DEBUG_MEMORY_INIT
882 bool "Debug memory initialisation" if EXPERT
885 Enable this for additional checks during memory initialisation.
886 The sanity checks verify aspects of the VM such as the memory model
887 and other information provided by the architecture. Verbose
888 information will be printed at KERN_DEBUG loglevel depending
889 on the mminit_loglevel= command-line option.
893 config MEMORY_NOTIFIER_ERROR_INJECT
894 tristate "Memory hotplug notifier error injection module"
895 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
897 This option provides the ability to inject artificial errors to
898 memory hotplug notifier chain callbacks. It is controlled through
899 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
901 If the notifier call chain should be failed with some events
902 notified, write the error code to "actions/<notifier event>/error".
904 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
906 # cd /sys/kernel/debug/notifier-error-inject/memory
907 # echo -12 > actions/MEM_GOING_OFFLINE/error
908 # echo offline > /sys/devices/system/memory/memoryXXX/state
909 bash: echo: write error: Cannot allocate memory
911 To compile this code as a module, choose M here: the module will
912 be called memory-notifier-error-inject.
916 config DEBUG_PER_CPU_MAPS
917 bool "Debug access to per_cpu maps"
918 depends on DEBUG_KERNEL
921 Say Y to verify that the per_cpu map being accessed has
922 been set up. This adds a fair amount of code to kernel memory
923 and decreases performance.
927 config DEBUG_KMAP_LOCAL
928 bool "Debug kmap_local temporary mappings"
929 depends on DEBUG_KERNEL && KMAP_LOCAL
931 This option enables additional error checking for the kmap_local
932 infrastructure. Disable for production use.
934 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
937 config DEBUG_KMAP_LOCAL_FORCE_MAP
938 bool "Enforce kmap_local temporary mappings"
939 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
941 select DEBUG_KMAP_LOCAL
943 This option enforces temporary mappings through the kmap_local
944 mechanism for non-highmem pages and on non-highmem systems.
945 Disable this for production systems!
948 bool "Highmem debugging"
949 depends on DEBUG_KERNEL && HIGHMEM
950 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
951 select DEBUG_KMAP_LOCAL
953 This option enables additional error checking for high memory
954 systems. Disable for production systems.
956 config HAVE_DEBUG_STACKOVERFLOW
959 config DEBUG_STACKOVERFLOW
960 bool "Check for stack overflows"
961 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
963 Say Y here if you want to check for overflows of kernel, IRQ
964 and exception stacks (if your architecture uses them). This
965 option will show detailed messages if free stack space drops
966 below a certain limit.
968 These kinds of bugs usually occur when call-chains in the
969 kernel get too deep, especially when interrupts are
972 Use this in cases where you see apparently random memory
973 corruption, especially if it appears in 'struct thread_info'
975 If in doubt, say "N".
977 source "lib/Kconfig.kasan"
978 source "lib/Kconfig.kfence"
980 endmenu # "Memory Debugging"
983 bool "Debug shared IRQ handlers"
984 depends on DEBUG_KERNEL
986 Enable this to generate a spurious interrupt just before a shared
987 interrupt handler is deregistered (generating one when registering
988 is currently disabled). Drivers need to handle this correctly. Some
989 don't and need to be caught.
991 menu "Debug Oops, Lockups and Hangs"
996 Say Y here to enable the kernel to panic when it oopses. This
997 has the same effect as setting oops=panic on the kernel command
1000 This feature is useful to ensure that the kernel does not do
1001 anything erroneous after an oops which could result in data
1002 corruption or other issues.
1006 config PANIC_ON_OOPS_VALUE
1009 default 0 if !PANIC_ON_OOPS
1010 default 1 if PANIC_ON_OOPS
1012 config PANIC_TIMEOUT
1016 Set the timeout value (in seconds) until a reboot occurs when
1017 the kernel panics. If n = 0, then we wait forever. A timeout
1018 value n > 0 will wait n seconds before rebooting, while a timeout
1019 value n < 0 will reboot immediately.
1021 config LOCKUP_DETECTOR
1024 config SOFTLOCKUP_DETECTOR
1025 bool "Detect Soft Lockups"
1026 depends on DEBUG_KERNEL && !S390
1027 select LOCKUP_DETECTOR
1029 Say Y here to enable the kernel to act as a watchdog to detect
1032 Softlockups are bugs that cause the kernel to loop in kernel
1033 mode for more than 20 seconds, without giving other tasks a
1034 chance to run. The current stack trace is displayed upon
1035 detection and the system will stay locked up.
1037 config BOOTPARAM_SOFTLOCKUP_PANIC
1038 bool "Panic (Reboot) On Soft Lockups"
1039 depends on SOFTLOCKUP_DETECTOR
1041 Say Y here to enable the kernel to panic on "soft lockups",
1042 which are bugs that cause the kernel to loop in kernel
1043 mode for more than 20 seconds (configurable using the watchdog_thresh
1044 sysctl), without giving other tasks a chance to run.
1046 The panic can be used in combination with panic_timeout,
1047 to cause the system to reboot automatically after a
1048 lockup has been detected. This feature is useful for
1049 high-availability systems that have uptime guarantees and
1050 where a lockup must be resolved ASAP.
1054 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
1056 depends on SOFTLOCKUP_DETECTOR
1058 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
1059 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
1061 config HARDLOCKUP_DETECTOR_PERF
1063 select SOFTLOCKUP_DETECTOR
1066 # Enables a timestamp based low pass filter to compensate for perf based
1067 # hard lockup detection which runs too fast due to turbo modes.
1069 config HARDLOCKUP_CHECK_TIMESTAMP
1073 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1074 # lockup detector rather than the perf based detector.
1076 config HARDLOCKUP_DETECTOR
1077 bool "Detect Hard Lockups"
1078 depends on DEBUG_KERNEL && !S390
1079 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1080 select LOCKUP_DETECTOR
1081 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1083 Say Y here to enable the kernel to act as a watchdog to detect
1086 Hardlockups are bugs that cause the CPU to loop in kernel mode
1087 for more than 10 seconds, without letting other interrupts have a
1088 chance to run. The current stack trace is displayed upon detection
1089 and the system will stay locked up.
1091 config BOOTPARAM_HARDLOCKUP_PANIC
1092 bool "Panic (Reboot) On Hard Lockups"
1093 depends on HARDLOCKUP_DETECTOR
1095 Say Y here to enable the kernel to panic on "hard lockups",
1096 which are bugs that cause the kernel to loop in kernel
1097 mode with interrupts disabled for more than 10 seconds (configurable
1098 using the watchdog_thresh sysctl).
1102 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
1104 depends on HARDLOCKUP_DETECTOR
1106 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
1107 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
1109 config DETECT_HUNG_TASK
1110 bool "Detect Hung Tasks"
1111 depends on DEBUG_KERNEL
1112 default SOFTLOCKUP_DETECTOR
1114 Say Y here to enable the kernel to detect "hung tasks",
1115 which are bugs that cause the task to be stuck in
1116 uninterruptible "D" state indefinitely.
1118 When a hung task is detected, the kernel will print the
1119 current stack trace (which you should report), but the
1120 task will stay in uninterruptible state. If lockdep is
1121 enabled then all held locks will also be reported. This
1122 feature has negligible overhead.
1124 config DEFAULT_HUNG_TASK_TIMEOUT
1125 int "Default timeout for hung task detection (in seconds)"
1126 depends on DETECT_HUNG_TASK
1129 This option controls the default timeout (in seconds) used
1130 to determine when a task has become non-responsive and should
1133 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1134 sysctl or by writing a value to
1135 /proc/sys/kernel/hung_task_timeout_secs.
1137 A timeout of 0 disables the check. The default is two minutes.
1138 Keeping the default should be fine in most cases.
1140 config BOOTPARAM_HUNG_TASK_PANIC
1141 bool "Panic (Reboot) On Hung Tasks"
1142 depends on DETECT_HUNG_TASK
1144 Say Y here to enable the kernel to panic on "hung tasks",
1145 which are bugs that cause the kernel to leave a task stuck
1146 in uninterruptible "D" state.
1148 The panic can be used in combination with panic_timeout,
1149 to cause the system to reboot automatically after a
1150 hung task has been detected. This feature is useful for
1151 high-availability systems that have uptime guarantees and
1152 where a hung tasks must be resolved ASAP.
1156 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
1158 depends on DETECT_HUNG_TASK
1160 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
1161 default 1 if BOOTPARAM_HUNG_TASK_PANIC
1164 bool "Detect Workqueue Stalls"
1165 depends on DEBUG_KERNEL
1167 Say Y here to enable stall detection on workqueues. If a
1168 worker pool doesn't make forward progress on a pending work
1169 item for over a given amount of time, 30s by default, a
1170 warning message is printed along with dump of workqueue
1171 state. This can be configured through kernel parameter
1172 "workqueue.watchdog_thresh" and its sysfs counterpart.
1175 tristate "Test module to generate lockups"
1178 This builds the "test_lockup" module that helps to make sure
1179 that watchdogs and lockup detectors are working properly.
1181 Depending on module parameters it could emulate soft or hard
1182 lockup, "hung task", or locking arbitrary lock for a long time.
1183 Also it could generate series of lockups with cooling-down periods.
1187 endmenu # "Debug lockups and hangs"
1189 menu "Scheduler Debugging"
1192 bool "Collect scheduler debugging info"
1193 depends on DEBUG_KERNEL && PROC_FS
1196 If you say Y here, the /proc/sched_debug file will be provided
1197 that can help debug the scheduler. The runtime overhead of this
1205 bool "Collect scheduler statistics"
1206 depends on DEBUG_KERNEL && PROC_FS
1209 If you say Y here, additional code will be inserted into the
1210 scheduler and related routines to collect statistics about
1211 scheduler behavior and provide them in /proc/schedstat. These
1212 stats may be useful for both tuning and debugging the scheduler
1213 If you aren't debugging the scheduler or trying to tune a specific
1214 application, you can say N to avoid the very slight overhead
1219 config DEBUG_TIMEKEEPING
1220 bool "Enable extra timekeeping sanity checking"
1222 This option will enable additional timekeeping sanity checks
1223 which may be helpful when diagnosing issues where timekeeping
1224 problems are suspected.
1226 This may include checks in the timekeeping hotpaths, so this
1227 option may have a (very small) performance impact to some
1232 config DEBUG_PREEMPT
1233 bool "Debug preemptible kernel"
1234 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1237 If you say Y here then the kernel will use a debug variant of the
1238 commonly used smp_processor_id() function and will print warnings
1239 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1240 will detect preemption count underflows.
1242 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1244 config LOCK_DEBUGGING_SUPPORT
1246 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1249 config PROVE_LOCKING
1250 bool "Lock debugging: prove locking correctness"
1251 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1253 select DEBUG_SPINLOCK
1254 select DEBUG_MUTEXES if !PREEMPT_RT
1255 select DEBUG_RT_MUTEXES if RT_MUTEXES
1257 select DEBUG_WW_MUTEX_SLOWPATH
1258 select DEBUG_LOCK_ALLOC
1259 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1260 select TRACE_IRQFLAGS
1263 This feature enables the kernel to prove that all locking
1264 that occurs in the kernel runtime is mathematically
1265 correct: that under no circumstance could an arbitrary (and
1266 not yet triggered) combination of observed locking
1267 sequences (on an arbitrary number of CPUs, running an
1268 arbitrary number of tasks and interrupt contexts) cause a
1271 In short, this feature enables the kernel to report locking
1272 related deadlocks before they actually occur.
1274 The proof does not depend on how hard and complex a
1275 deadlock scenario would be to trigger: how many
1276 participant CPUs, tasks and irq-contexts would be needed
1277 for it to trigger. The proof also does not depend on
1278 timing: if a race and a resulting deadlock is possible
1279 theoretically (no matter how unlikely the race scenario
1280 is), it will be proven so and will immediately be
1281 reported by the kernel (once the event is observed that
1282 makes the deadlock theoretically possible).
1284 If a deadlock is impossible (i.e. the locking rules, as
1285 observed by the kernel, are mathematically correct), the
1286 kernel reports nothing.
1288 NOTE: this feature can also be enabled for rwlocks, mutexes
1289 and rwsems - in which case all dependencies between these
1290 different locking variants are observed and mapped too, and
1291 the proof of observed correctness is also maintained for an
1292 arbitrary combination of these separate locking variants.
1294 For more details, see Documentation/locking/lockdep-design.rst.
1296 config PROVE_RAW_LOCK_NESTING
1297 bool "Enable raw_spinlock - spinlock nesting checks"
1298 depends on PROVE_LOCKING
1301 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1302 that the lock nesting rules for PREEMPT_RT enabled kernels are
1305 NOTE: There are known nesting problems. So if you enable this
1306 option expect lockdep splats until these problems have been fully
1307 addressed which is work in progress. This config switch allows to
1308 identify and analyze these problems. It will be removed and the
1309 check permanently enabled once the main issues have been fixed.
1311 If unsure, select N.
1314 bool "Lock usage statistics"
1315 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1317 select DEBUG_SPINLOCK
1318 select DEBUG_MUTEXES if !PREEMPT_RT
1319 select DEBUG_RT_MUTEXES if RT_MUTEXES
1320 select DEBUG_LOCK_ALLOC
1323 This feature enables tracking lock contention points
1325 For more details, see Documentation/locking/lockstat.rst
1327 This also enables lock events required by "perf lock",
1329 If you want to use "perf lock", you also need to turn on
1330 CONFIG_EVENT_TRACING.
1332 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1333 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1335 config DEBUG_RT_MUTEXES
1336 bool "RT Mutex debugging, deadlock detection"
1337 depends on DEBUG_KERNEL && RT_MUTEXES
1339 This allows rt mutex semantics violations and rt mutex related
1340 deadlocks (lockups) to be detected and reported automatically.
1342 config DEBUG_SPINLOCK
1343 bool "Spinlock and rw-lock debugging: basic checks"
1344 depends on DEBUG_KERNEL
1345 select UNINLINE_SPIN_UNLOCK
1347 Say Y here and build SMP to catch missing spinlock initialization
1348 and certain other kinds of spinlock errors commonly made. This is
1349 best used in conjunction with the NMI watchdog so that spinlock
1350 deadlocks are also debuggable.
1352 config DEBUG_MUTEXES
1353 bool "Mutex debugging: basic checks"
1354 depends on DEBUG_KERNEL && !PREEMPT_RT
1356 This feature allows mutex semantics violations to be detected and
1359 config DEBUG_WW_MUTEX_SLOWPATH
1360 bool "Wait/wound mutex debugging: Slowpath testing"
1361 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1362 select DEBUG_LOCK_ALLOC
1363 select DEBUG_SPINLOCK
1364 select DEBUG_MUTEXES if !PREEMPT_RT
1365 select DEBUG_RT_MUTEXES if PREEMPT_RT
1367 This feature enables slowpath testing for w/w mutex users by
1368 injecting additional -EDEADLK wound/backoff cases. Together with
1369 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1370 will test all possible w/w mutex interface abuse with the
1371 exception of simply not acquiring all the required locks.
1372 Note that this feature can introduce significant overhead, so
1373 it really should not be enabled in a production or distro kernel,
1374 even a debug kernel. If you are a driver writer, enable it. If
1375 you are a distro, do not.
1378 bool "RW Semaphore debugging: basic checks"
1379 depends on DEBUG_KERNEL
1381 This debugging feature allows mismatched rw semaphore locks
1382 and unlocks to be detected and reported.
1384 config DEBUG_LOCK_ALLOC
1385 bool "Lock debugging: detect incorrect freeing of live locks"
1386 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1387 select DEBUG_SPINLOCK
1388 select DEBUG_MUTEXES if !PREEMPT_RT
1389 select DEBUG_RT_MUTEXES if RT_MUTEXES
1392 This feature will check whether any held lock (spinlock, rwlock,
1393 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1394 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1395 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1396 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1397 held during task exit.
1401 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1406 config LOCKDEP_SMALL
1410 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1411 depends on LOCKDEP && !LOCKDEP_SMALL
1415 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1417 config LOCKDEP_CHAINS_BITS
1418 int "Bitsize for MAX_LOCKDEP_CHAINS"
1419 depends on LOCKDEP && !LOCKDEP_SMALL
1423 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1425 config LOCKDEP_STACK_TRACE_BITS
1426 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1427 depends on LOCKDEP && !LOCKDEP_SMALL
1431 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1433 config LOCKDEP_STACK_TRACE_HASH_BITS
1434 int "Bitsize for STACK_TRACE_HASH_SIZE"
1435 depends on LOCKDEP && !LOCKDEP_SMALL
1439 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1441 config LOCKDEP_CIRCULAR_QUEUE_BITS
1442 int "Bitsize for elements in circular_queue struct"
1447 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1449 config DEBUG_LOCKDEP
1450 bool "Lock dependency engine debugging"
1451 depends on DEBUG_KERNEL && LOCKDEP
1452 select DEBUG_IRQFLAGS
1454 If you say Y here, the lock dependency engine will do
1455 additional runtime checks to debug itself, at the price
1456 of more runtime overhead.
1458 config DEBUG_ATOMIC_SLEEP
1459 bool "Sleep inside atomic section checking"
1460 select PREEMPT_COUNT
1461 depends on DEBUG_KERNEL
1462 depends on !ARCH_NO_PREEMPT
1464 If you say Y here, various routines which may sleep will become very
1465 noisy if they are called inside atomic sections: when a spinlock is
1466 held, inside an rcu read side critical section, inside preempt disabled
1467 sections, inside an interrupt, etc...
1469 config DEBUG_LOCKING_API_SELFTESTS
1470 bool "Locking API boot-time self-tests"
1471 depends on DEBUG_KERNEL
1473 Say Y here if you want the kernel to run a short self-test during
1474 bootup. The self-test checks whether common types of locking bugs
1475 are detected by debugging mechanisms or not. (if you disable
1476 lock debugging then those bugs won't be detected of course.)
1477 The following locking APIs are covered: spinlocks, rwlocks,
1480 config LOCK_TORTURE_TEST
1481 tristate "torture tests for locking"
1482 depends on DEBUG_KERNEL
1485 This option provides a kernel module that runs torture tests
1486 on kernel locking primitives. The kernel module may be built
1487 after the fact on the running kernel to be tested, if desired.
1489 Say Y here if you want kernel locking-primitive torture tests
1490 to be built into the kernel.
1491 Say M if you want these torture tests to build as a module.
1492 Say N if you are unsure.
1494 config WW_MUTEX_SELFTEST
1495 tristate "Wait/wound mutex selftests"
1497 This option provides a kernel module that runs tests on the
1498 on the struct ww_mutex locking API.
1500 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1501 with this test harness.
1503 Say M if you want these self tests to build as a module.
1504 Say N if you are unsure.
1506 config SCF_TORTURE_TEST
1507 tristate "torture tests for smp_call_function*()"
1508 depends on DEBUG_KERNEL
1511 This option provides a kernel module that runs torture tests
1512 on the smp_call_function() family of primitives. The kernel
1513 module may be built after the fact on the running kernel to
1514 be tested, if desired.
1516 config CSD_LOCK_WAIT_DEBUG
1517 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1518 depends on DEBUG_KERNEL
1522 This option enables debug prints when CPUs are slow to respond
1523 to the smp_call_function*() IPI wrappers. These debug prints
1524 include the IPI handler function currently executing (if any)
1525 and relevant stack traces.
1527 endmenu # lock debugging
1529 config TRACE_IRQFLAGS
1530 depends on TRACE_IRQFLAGS_SUPPORT
1533 Enables hooks to interrupt enabling and disabling for
1534 either tracing or lock debugging.
1536 config TRACE_IRQFLAGS_NMI
1538 depends on TRACE_IRQFLAGS
1539 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1541 config DEBUG_IRQFLAGS
1542 bool "Debug IRQ flag manipulation"
1544 Enables checks for potentially unsafe enabling or disabling of
1545 interrupts, such as calling raw_local_irq_restore() when interrupts
1549 bool "Stack backtrace support"
1550 depends on STACKTRACE_SUPPORT
1552 This option causes the kernel to create a /proc/pid/stack for
1553 every process, showing its current stack trace.
1554 It is also used by various kernel debugging features that require
1555 stack trace generation.
1557 config WARN_ALL_UNSEEDED_RANDOM
1558 bool "Warn for all uses of unseeded randomness"
1561 Some parts of the kernel contain bugs relating to their use of
1562 cryptographically secure random numbers before it's actually possible
1563 to generate those numbers securely. This setting ensures that these
1564 flaws don't go unnoticed, by enabling a message, should this ever
1565 occur. This will allow people with obscure setups to know when things
1566 are going wrong, so that they might contact developers about fixing
1569 Unfortunately, on some models of some architectures getting
1570 a fully seeded CRNG is extremely difficult, and so this can
1571 result in dmesg getting spammed for a surprisingly long
1572 time. This is really bad from a security perspective, and
1573 so architecture maintainers really need to do what they can
1574 to get the CRNG seeded sooner after the system is booted.
1575 However, since users cannot do anything actionable to
1576 address this, by default the kernel will issue only a single
1577 warning for the first use of unseeded randomness.
1579 Say Y here if you want to receive warnings for all uses of
1580 unseeded randomness. This will be of use primarily for
1581 those developers interested in improving the security of
1582 Linux kernels running on their architecture (or
1585 config DEBUG_KOBJECT
1586 bool "kobject debugging"
1587 depends on DEBUG_KERNEL
1589 If you say Y here, some extra kobject debugging messages will be sent
1592 config DEBUG_KOBJECT_RELEASE
1593 bool "kobject release debugging"
1594 depends on DEBUG_OBJECTS_TIMERS
1596 kobjects are reference counted objects. This means that their
1597 last reference count put is not predictable, and the kobject can
1598 live on past the point at which a driver decides to drop it's
1599 initial reference to the kobject gained on allocation. An
1600 example of this would be a struct device which has just been
1603 However, some buggy drivers assume that after such an operation,
1604 the memory backing the kobject can be immediately freed. This
1605 goes completely against the principles of a refcounted object.
1607 If you say Y here, the kernel will delay the release of kobjects
1608 on the last reference count to improve the visibility of this
1609 kind of kobject release bug.
1611 config HAVE_DEBUG_BUGVERBOSE
1614 menu "Debug kernel data structures"
1617 bool "Debug linked list manipulation"
1618 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1620 Enable this to turn on extended checks in the linked-list
1626 bool "Debug priority linked list manipulation"
1627 depends on DEBUG_KERNEL
1629 Enable this to turn on extended checks in the priority-ordered
1630 linked-list (plist) walking routines. This checks the entire
1631 list multiple times during each manipulation.
1636 bool "Debug SG table operations"
1637 depends on DEBUG_KERNEL
1639 Enable this to turn on checks on scatter-gather tables. This can
1640 help find problems with drivers that do not properly initialize
1645 config DEBUG_NOTIFIERS
1646 bool "Debug notifier call chains"
1647 depends on DEBUG_KERNEL
1649 Enable this to turn on sanity checking for notifier call chains.
1650 This is most useful for kernel developers to make sure that
1651 modules properly unregister themselves from notifier chains.
1652 This is a relatively cheap check but if you care about maximum
1655 config BUG_ON_DATA_CORRUPTION
1656 bool "Trigger a BUG when data corruption is detected"
1659 Select this option if the kernel should BUG when it encounters
1660 data corruption in kernel memory structures when they get checked
1667 config DEBUG_CREDENTIALS
1668 bool "Debug credential management"
1669 depends on DEBUG_KERNEL
1671 Enable this to turn on some debug checking for credential
1672 management. The additional code keeps track of the number of
1673 pointers from task_structs to any given cred struct, and checks to
1674 see that this number never exceeds the usage count of the cred
1677 Furthermore, if SELinux is enabled, this also checks that the
1678 security pointer in the cred struct is never seen to be invalid.
1682 source "kernel/rcu/Kconfig.debug"
1684 config DEBUG_WQ_FORCE_RR_CPU
1685 bool "Force round-robin CPU selection for unbound work items"
1686 depends on DEBUG_KERNEL
1689 Workqueue used to implicitly guarantee that work items queued
1690 without explicit CPU specified are put on the local CPU. This
1691 guarantee is no longer true and while local CPU is still
1692 preferred work items may be put on foreign CPUs. Kernel
1693 parameter "workqueue.debug_force_rr_cpu" is added to force
1694 round-robin CPU selection to flush out usages which depend on the
1695 now broken guarantee. This config option enables the debug
1696 feature by default. When enabled, memory and cache locality will
1699 config CPU_HOTPLUG_STATE_CONTROL
1700 bool "Enable CPU hotplug state control"
1701 depends on DEBUG_KERNEL
1702 depends on HOTPLUG_CPU
1705 Allows to write steps between "offline" and "online" to the CPUs
1706 sysfs target file so states can be stepped granular. This is a debug
1707 option for now as the hotplug machinery cannot be stopped and
1708 restarted at arbitrary points yet.
1710 Say N if your are unsure.
1713 bool "Latency measuring infrastructure"
1714 depends on DEBUG_KERNEL
1715 depends on STACKTRACE_SUPPORT
1717 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1723 Enable this option if you want to use the LatencyTOP tool
1724 to find out which userspace is blocking on what kernel operations.
1726 source "kernel/trace/Kconfig"
1728 config PROVIDE_OHCI1394_DMA_INIT
1729 bool "Remote debugging over FireWire early on boot"
1730 depends on PCI && X86
1732 If you want to debug problems which hang or crash the kernel early
1733 on boot and the crashing machine has a FireWire port, you can use
1734 this feature to remotely access the memory of the crashed machine
1735 over FireWire. This employs remote DMA as part of the OHCI1394
1736 specification which is now the standard for FireWire controllers.
1738 With remote DMA, you can monitor the printk buffer remotely using
1739 firescope and access all memory below 4GB using fireproxy from gdb.
1740 Even controlling a kernel debugger is possible using remote DMA.
1744 If ohci1394_dma=early is used as boot parameter, it will initialize
1745 all OHCI1394 controllers which are found in the PCI config space.
1747 As all changes to the FireWire bus such as enabling and disabling
1748 devices cause a bus reset and thereby disable remote DMA for all
1749 devices, be sure to have the cable plugged and FireWire enabled on
1750 the debugging host before booting the debug target for debugging.
1752 This code (~1k) is freed after boot. By then, the firewire stack
1753 in charge of the OHCI-1394 controllers should be used instead.
1755 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1757 source "samples/Kconfig"
1759 config ARCH_HAS_DEVMEM_IS_ALLOWED
1762 config STRICT_DEVMEM
1763 bool "Filter access to /dev/mem"
1764 depends on MMU && DEVMEM
1765 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1766 default y if PPC || X86 || ARM64
1768 If this option is disabled, you allow userspace (root) access to all
1769 of memory, including kernel and userspace memory. Accidental
1770 access to this is obviously disastrous, but specific access can
1771 be used by people debugging the kernel. Note that with PAT support
1772 enabled, even in this case there are restrictions on /dev/mem
1773 use due to the cache aliasing requirements.
1775 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1776 file only allows userspace access to PCI space and the BIOS code and
1777 data regions. This is sufficient for dosemu and X and all common
1782 config IO_STRICT_DEVMEM
1783 bool "Filter I/O access to /dev/mem"
1784 depends on STRICT_DEVMEM
1786 If this option is disabled, you allow userspace (root) access to all
1787 io-memory regardless of whether a driver is actively using that
1788 range. Accidental access to this is obviously disastrous, but
1789 specific access can be used by people debugging kernel drivers.
1791 If this option is switched on, the /dev/mem file only allows
1792 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1793 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1794 if the driver using a given range cannot be disabled.
1798 menu "$(SRCARCH) Debugging"
1800 source "arch/$(SRCARCH)/Kconfig.debug"
1804 menu "Kernel Testing and Coverage"
1806 source "lib/kunit/Kconfig"
1808 config NOTIFIER_ERROR_INJECTION
1809 tristate "Notifier error injection"
1810 depends on DEBUG_KERNEL
1813 This option provides the ability to inject artificial errors to
1814 specified notifier chain callbacks. It is useful to test the error
1815 handling of notifier call chain failures.
1819 config PM_NOTIFIER_ERROR_INJECT
1820 tristate "PM notifier error injection module"
1821 depends on PM && NOTIFIER_ERROR_INJECTION
1822 default m if PM_DEBUG
1824 This option provides the ability to inject artificial errors to
1825 PM notifier chain callbacks. It is controlled through debugfs
1826 interface /sys/kernel/debug/notifier-error-inject/pm
1828 If the notifier call chain should be failed with some events
1829 notified, write the error code to "actions/<notifier event>/error".
1831 Example: Inject PM suspend error (-12 = -ENOMEM)
1833 # cd /sys/kernel/debug/notifier-error-inject/pm/
1834 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1835 # echo mem > /sys/power/state
1836 bash: echo: write error: Cannot allocate memory
1838 To compile this code as a module, choose M here: the module will
1839 be called pm-notifier-error-inject.
1843 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1844 tristate "OF reconfig notifier error injection module"
1845 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1847 This option provides the ability to inject artificial errors to
1848 OF reconfig notifier chain callbacks. It is controlled
1849 through debugfs interface under
1850 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1852 If the notifier call chain should be failed with some events
1853 notified, write the error code to "actions/<notifier event>/error".
1855 To compile this code as a module, choose M here: the module will
1856 be called of-reconfig-notifier-error-inject.
1860 config NETDEV_NOTIFIER_ERROR_INJECT
1861 tristate "Netdev notifier error injection module"
1862 depends on NET && NOTIFIER_ERROR_INJECTION
1864 This option provides the ability to inject artificial errors to
1865 netdevice notifier chain callbacks. It is controlled through debugfs
1866 interface /sys/kernel/debug/notifier-error-inject/netdev
1868 If the notifier call chain should be failed with some events
1869 notified, write the error code to "actions/<notifier event>/error".
1871 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1873 # cd /sys/kernel/debug/notifier-error-inject/netdev
1874 # echo -22 > actions/NETDEV_CHANGEMTU/error
1875 # ip link set eth0 mtu 1024
1876 RTNETLINK answers: Invalid argument
1878 To compile this code as a module, choose M here: the module will
1879 be called netdev-notifier-error-inject.
1883 config FUNCTION_ERROR_INJECTION
1885 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1887 config FAULT_INJECTION
1888 bool "Fault-injection framework"
1889 depends on DEBUG_KERNEL
1891 Provide fault-injection framework.
1892 For more details, see Documentation/fault-injection/.
1895 bool "Fault-injection capability for kmalloc"
1896 depends on FAULT_INJECTION
1897 depends on SLAB || SLUB
1899 Provide fault-injection capability for kmalloc.
1901 config FAIL_PAGE_ALLOC
1902 bool "Fault-injection capability for alloc_pages()"
1903 depends on FAULT_INJECTION
1905 Provide fault-injection capability for alloc_pages().
1907 config FAULT_INJECTION_USERCOPY
1908 bool "Fault injection capability for usercopy functions"
1909 depends on FAULT_INJECTION
1911 Provides fault-injection capability to inject failures
1912 in usercopy functions (copy_from_user(), get_user(), ...).
1914 config FAIL_MAKE_REQUEST
1915 bool "Fault-injection capability for disk IO"
1916 depends on FAULT_INJECTION && BLOCK
1918 Provide fault-injection capability for disk IO.
1920 config FAIL_IO_TIMEOUT
1921 bool "Fault-injection capability for faking disk interrupts"
1922 depends on FAULT_INJECTION && BLOCK
1924 Provide fault-injection capability on end IO handling. This
1925 will make the block layer "forget" an interrupt as configured,
1926 thus exercising the error handling.
1928 Only works with drivers that use the generic timeout handling,
1929 for others it won't do anything.
1932 bool "Fault-injection capability for futexes"
1934 depends on FAULT_INJECTION && FUTEX
1936 Provide fault-injection capability for futexes.
1938 config FAULT_INJECTION_DEBUG_FS
1939 bool "Debugfs entries for fault-injection capabilities"
1940 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1942 Enable configuration of fault-injection capabilities via debugfs.
1944 config FAIL_FUNCTION
1945 bool "Fault-injection capability for functions"
1946 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1948 Provide function-based fault-injection capability.
1949 This will allow you to override a specific function with a return
1950 with given return value. As a result, function caller will see
1951 an error value and have to handle it. This is useful to test the
1952 error handling in various subsystems.
1954 config FAIL_MMC_REQUEST
1955 bool "Fault-injection capability for MMC IO"
1956 depends on FAULT_INJECTION_DEBUG_FS && MMC
1958 Provide fault-injection capability for MMC IO.
1959 This will make the mmc core return data errors. This is
1960 useful to test the error handling in the mmc block device
1961 and to test how the mmc host driver handles retries from
1965 bool "Fault-injection capability for SunRPC"
1966 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1968 Provide fault-injection capability for SunRPC and
1971 config FAULT_INJECTION_STACKTRACE_FILTER
1972 bool "stacktrace filter for fault-injection capabilities"
1973 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1976 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1978 Provide stacktrace filter for fault-injection capabilities
1980 config ARCH_HAS_KCOV
1983 An architecture should select this when it can successfully
1984 build and run with CONFIG_KCOV. This typically requires
1985 disabling instrumentation for some early boot code.
1987 config CC_HAS_SANCOV_TRACE_PC
1988 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1992 bool "Code coverage for fuzzing"
1993 depends on ARCH_HAS_KCOV
1994 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1995 depends on !ARCH_WANTS_NO_INSTR || STACK_VALIDATION || \
1996 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
1998 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2000 KCOV exposes kernel code coverage information in a form suitable
2001 for coverage-guided fuzzing (randomized testing).
2003 If RANDOMIZE_BASE is enabled, PC values will not be stable across
2004 different machines and across reboots. If you need stable PC values,
2005 disable RANDOMIZE_BASE.
2007 For more details, see Documentation/dev-tools/kcov.rst.
2009 config KCOV_ENABLE_COMPARISONS
2010 bool "Enable comparison operands collection by KCOV"
2012 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2014 KCOV also exposes operands of every comparison in the instrumented
2015 code along with operand sizes and PCs of the comparison instructions.
2016 These operands can be used by fuzzing engines to improve the quality
2017 of fuzzing coverage.
2019 config KCOV_INSTRUMENT_ALL
2020 bool "Instrument all code by default"
2024 If you are doing generic system call fuzzing (like e.g. syzkaller),
2025 then you will want to instrument the whole kernel and you should
2026 say y here. If you are doing more targeted fuzzing (like e.g.
2027 filesystem fuzzing with AFL) then you will want to enable coverage
2028 for more specific subsets of files, and should say n here.
2030 config KCOV_IRQ_AREA_SIZE
2031 hex "Size of interrupt coverage collection area in words"
2035 KCOV uses preallocated per-cpu areas to collect coverage from
2036 soft interrupts. This specifies the size of those areas in the
2037 number of unsigned long words.
2039 menuconfig RUNTIME_TESTING_MENU
2040 bool "Runtime Testing"
2043 if RUNTIME_TESTING_MENU
2046 tristate "Linux Kernel Dump Test Tool Module"
2049 This module enables testing of the different dumping mechanisms by
2050 inducing system failures at predefined crash points.
2051 If you don't need it: say N
2052 Choose M here to compile this code as a module. The module will be
2055 Documentation on how to use the module can be found in
2056 Documentation/fault-injection/provoke-crashes.rst
2058 config TEST_LIST_SORT
2059 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2061 default KUNIT_ALL_TESTS
2063 Enable this to turn on 'list_sort()' function test. This test is
2064 executed only once during system boot (so affects only boot time),
2065 or at module load time.
2069 config TEST_MIN_HEAP
2070 tristate "Min heap test"
2071 depends on DEBUG_KERNEL || m
2073 Enable this to turn on min heap function tests. This test is
2074 executed only once during system boot (so affects only boot time),
2075 or at module load time.
2080 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2082 default KUNIT_ALL_TESTS
2084 This option enables the self-test function of 'sort()' at boot,
2085 or at module load time.
2090 tristate "64bit/32bit division and modulo test"
2091 depends on DEBUG_KERNEL || m
2093 Enable this to turn on 'do_div()' function test. This test is
2094 executed only once during system boot (so affects only boot time),
2095 or at module load time.
2099 config KPROBES_SANITY_TEST
2100 tristate "Kprobes sanity tests"
2101 depends on DEBUG_KERNEL
2105 This option provides for testing basic kprobes functionality on
2106 boot. Samples of kprobe and kretprobe are inserted and
2107 verified for functionality.
2109 Say N if you are unsure.
2111 config BACKTRACE_SELF_TEST
2112 tristate "Self test for the backtrace code"
2113 depends on DEBUG_KERNEL
2115 This option provides a kernel module that can be used to test
2116 the kernel stack backtrace code. This option is not useful
2117 for distributions or general kernels, but only for kernel
2118 developers working on architecture code.
2120 Note that if you want to also test saved backtraces, you will
2121 have to enable STACKTRACE as well.
2123 Say N if you are unsure.
2125 config TEST_REF_TRACKER
2126 tristate "Self test for reference tracker"
2127 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2130 This option provides a kernel module performing tests
2131 using reference tracker infrastructure.
2133 Say N if you are unsure.
2136 tristate "Red-Black tree test"
2137 depends on DEBUG_KERNEL
2139 A benchmark measuring the performance of the rbtree library.
2140 Also includes rbtree invariant checks.
2142 config REED_SOLOMON_TEST
2143 tristate "Reed-Solomon library test"
2144 depends on DEBUG_KERNEL || m
2146 select REED_SOLOMON_ENC16
2147 select REED_SOLOMON_DEC16
2149 This option enables the self-test function of rslib at boot,
2150 or at module load time.
2154 config INTERVAL_TREE_TEST
2155 tristate "Interval tree test"
2156 depends on DEBUG_KERNEL
2157 select INTERVAL_TREE
2159 A benchmark measuring the performance of the interval tree library
2162 tristate "Per cpu operations test"
2163 depends on m && DEBUG_KERNEL
2165 Enable this option to build test module which validates per-cpu
2170 config ATOMIC64_SELFTEST
2171 tristate "Perform an atomic64_t self-test"
2173 Enable this option to test the atomic64_t functions at boot or
2174 at module load time.
2178 config ASYNC_RAID6_TEST
2179 tristate "Self test for hardware accelerated raid6 recovery"
2180 depends on ASYNC_RAID6_RECOV
2183 This is a one-shot self test that permutes through the
2184 recovery of all the possible two disk failure scenarios for a
2185 N-disk array. Recovery is performed with the asynchronous
2186 raid6 recovery routines, and will optionally use an offload
2187 engine if one is available.
2192 tristate "Test functions located in the hexdump module at runtime"
2194 config STRING_SELFTEST
2195 tristate "Test string functions at runtime"
2197 config TEST_STRING_HELPERS
2198 tristate "Test functions located in the string_helpers module at runtime"
2201 tristate "Test strscpy*() family of functions at runtime"
2204 tristate "Test kstrto*() family of functions at runtime"
2207 tristate "Test printf() family of functions at runtime"
2210 tristate "Test scanf() family of functions at runtime"
2213 tristate "Test bitmap_*() family of functions at runtime"
2215 Enable this option to test the bitmap functions at boot.
2220 tristate "Test functions located in the uuid module at runtime"
2223 tristate "Test the XArray code at runtime"
2225 config TEST_OVERFLOW
2226 tristate "Test check_*_overflow() functions at runtime"
2228 config TEST_RHASHTABLE
2229 tristate "Perform selftest on resizable hash table"
2231 Enable this option to test the rhashtable functions at boot.
2236 tristate "Perform selftest on siphash functions"
2238 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2239 functions on boot (or module load).
2241 This is intended to help people writing architecture-specific
2242 optimized versions. If unsure, say N.
2245 tristate "Perform selftest on IDA functions"
2248 tristate "Perform selftest on priority array manager"
2251 Enable this option to test priority array manager on boot
2256 config TEST_IRQ_TIMINGS
2257 bool "IRQ timings selftest"
2258 depends on IRQ_TIMINGS
2260 Enable this option to test the irq timings code on boot.
2265 tristate "Test module loading with 'hello world' module"
2268 This builds the "test_module" module that emits "Hello, world"
2269 on printk when loaded. It is designed to be used for basic
2270 evaluation of the module loading subsystem (for example when
2271 validating module verification). It lacks any extra dependencies,
2272 and will not normally be loaded by the system unless explicitly
2278 tristate "Test module for compilation of bitops operations"
2281 This builds the "test_bitops" module that is much like the
2282 TEST_LKM module except that it does a basic exercise of the
2283 set/clear_bit macros and get_count_order/long to make sure there are
2284 no compiler warnings from C=1 sparse checker or -Wextra
2285 compilations. It has no dependencies and doesn't run or load unless
2286 explicitly requested by name. for example: modprobe test_bitops.
2291 tristate "Test module for stress/performance analysis of vmalloc allocator"
2296 This builds the "test_vmalloc" module that should be used for
2297 stress and performance analysis. So, any new change for vmalloc
2298 subsystem can be evaluated from performance and stability point
2303 config TEST_USER_COPY
2304 tristate "Test user/kernel boundary protections"
2307 This builds the "test_user_copy" module that runs sanity checks
2308 on the copy_to/from_user infrastructure, making sure basic
2309 user/kernel boundary testing is working. If it fails to load,
2310 a regression has been detected in the user/kernel memory boundary
2316 tristate "Test BPF filter functionality"
2319 This builds the "test_bpf" module that runs various test vectors
2320 against the BPF interpreter or BPF JIT compiler depending on the
2321 current setting. This is in particular useful for BPF JIT compiler
2322 development, but also to run regression tests against changes in
2323 the interpreter code. It also enables test stubs for eBPF maps and
2324 verifier used by user space verifier testsuite.
2328 config TEST_BLACKHOLE_DEV
2329 tristate "Test blackhole netdev functionality"
2332 This builds the "test_blackhole_dev" module that validates the
2333 data path through this blackhole netdev.
2337 config FIND_BIT_BENCHMARK
2338 tristate "Test find_bit functions"
2340 This builds the "test_find_bit" module that measure find_*_bit()
2341 functions performance.
2345 config TEST_FIRMWARE
2346 tristate "Test firmware loading via userspace interface"
2347 depends on FW_LOADER
2349 This builds the "test_firmware" module that creates a userspace
2350 interface for testing firmware loading. This can be used to
2351 control the triggering of firmware loading without needing an
2352 actual firmware-using device. The contents can be rechecked by
2358 tristate "sysctl test driver"
2359 depends on PROC_SYSCTL
2361 This builds the "test_sysctl" module. This driver enables to test the
2362 proc sysctl interfaces available to drivers safely without affecting
2363 production knobs which might alter system functionality.
2367 config BITFIELD_KUNIT
2368 tristate "KUnit test bitfield functions at runtime"
2371 Enable this option to test the bitfield functions at boot.
2373 KUnit tests run during boot and output the results to the debug log
2374 in TAP format (http://testanything.org/). Only useful for kernel devs
2375 running the KUnit test harness, and not intended for inclusion into a
2378 For more information on KUnit and unit tests in general please refer
2379 to the KUnit documentation in Documentation/dev-tools/kunit/.
2383 config HASH_KUNIT_TEST
2384 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2386 default KUNIT_ALL_TESTS
2388 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2389 integer (<linux/hash.h>) hash functions on boot.
2391 KUnit tests run during boot and output the results to the debug log
2392 in TAP format (https://testanything.org/). Only useful for kernel devs
2393 running the KUnit test harness, and not intended for inclusion into a
2396 For more information on KUnit and unit tests in general please refer
2397 to the KUnit documentation in Documentation/dev-tools/kunit/.
2399 This is intended to help people writing architecture-specific
2400 optimized versions. If unsure, say N.
2402 config RESOURCE_KUNIT_TEST
2403 tristate "KUnit test for resource API"
2406 This builds the resource API unit test.
2407 Tests the logic of API provided by resource.c and ioport.h.
2408 For more information on KUnit and unit tests in general please refer
2409 to the KUnit documentation in Documentation/dev-tools/kunit/.
2413 config SYSCTL_KUNIT_TEST
2414 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2416 default KUNIT_ALL_TESTS
2418 This builds the proc sysctl unit test, which runs on boot.
2419 Tests the API contract and implementation correctness of sysctl.
2420 For more information on KUnit and unit tests in general please refer
2421 to the KUnit documentation in Documentation/dev-tools/kunit/.
2425 config LIST_KUNIT_TEST
2426 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2428 default KUNIT_ALL_TESTS
2430 This builds the linked list KUnit test suite.
2431 It tests that the API and basic functionality of the list_head type
2432 and associated macros.
2434 KUnit tests run during boot and output the results to the debug log
2435 in TAP format (https://testanything.org/). Only useful for kernel devs
2436 running the KUnit test harness, and not intended for inclusion into a
2439 For more information on KUnit and unit tests in general please refer
2440 to the KUnit documentation in Documentation/dev-tools/kunit/.
2444 config LINEAR_RANGES_TEST
2445 tristate "KUnit test for linear_ranges"
2447 select LINEAR_RANGES
2449 This builds the linear_ranges unit test, which runs on boot.
2450 Tests the linear_ranges logic correctness.
2451 For more information on KUnit and unit tests in general please refer
2452 to the KUnit documentation in Documentation/dev-tools/kunit/.
2456 config CMDLINE_KUNIT_TEST
2457 tristate "KUnit test for cmdline API"
2460 This builds the cmdline API unit test.
2461 Tests the logic of API provided by cmdline.c.
2462 For more information on KUnit and unit tests in general please refer
2463 to the KUnit documentation in Documentation/dev-tools/kunit/.
2468 tristate "KUnit test for bits.h"
2471 This builds the bits unit test.
2472 Tests the logic of macros defined in bits.h.
2473 For more information on KUnit and unit tests in general please refer
2474 to the KUnit documentation in Documentation/dev-tools/kunit/.
2478 config SLUB_KUNIT_TEST
2479 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2480 depends on SLUB_DEBUG && KUNIT
2481 default KUNIT_ALL_TESTS
2483 This builds SLUB allocator unit test.
2484 Tests SLUB cache debugging functionality.
2485 For more information on KUnit and unit tests in general please refer
2486 to the KUnit documentation in Documentation/dev-tools/kunit/.
2490 config RATIONAL_KUNIT_TEST
2491 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2492 depends on KUNIT && RATIONAL
2493 default KUNIT_ALL_TESTS
2495 This builds the rational math unit test.
2496 For more information on KUnit and unit tests in general please refer
2497 to the KUnit documentation in Documentation/dev-tools/kunit/.
2501 config MEMCPY_KUNIT_TEST
2502 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2504 default KUNIT_ALL_TESTS
2506 Builds unit tests for memcpy(), memmove(), and memset() functions.
2507 For more information on KUnit and unit tests in general please refer
2508 to the KUnit documentation in Documentation/dev-tools/kunit/.
2513 tristate "udelay test driver"
2515 This builds the "udelay_test" module that helps to make sure
2516 that udelay() is working properly.
2520 config TEST_STATIC_KEYS
2521 tristate "Test static keys"
2524 Test the static key interfaces.
2529 tristate "kmod stress tester"
2531 depends on NETDEVICES && NET_CORE && INET # for TUN
2533 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2539 Test the kernel's module loading mechanism: kmod. kmod implements
2540 support to load modules using the Linux kernel's usermode helper.
2541 This test provides a series of tests against kmod.
2543 Although technically you can either build test_kmod as a module or
2544 into the kernel we disallow building it into the kernel since
2545 it stress tests request_module() and this will very likely cause
2546 some issues by taking over precious threads available from other
2547 module load requests, ultimately this could be fatal.
2551 tools/testing/selftests/kmod/kmod.sh --help
2555 config TEST_DEBUG_VIRTUAL
2556 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2557 depends on DEBUG_VIRTUAL
2559 Test the kernel's ability to detect incorrect calls to
2560 virt_to_phys() done against the non-linear part of the
2561 kernel's virtual address map.
2565 config TEST_MEMCAT_P
2566 tristate "Test memcat_p() helper function"
2568 Test the memcat_p() helper for correctly merging two
2569 pointer arrays together.
2573 config TEST_LIVEPATCH
2574 tristate "Test livepatching"
2576 depends on DYNAMIC_DEBUG
2577 depends on LIVEPATCH
2580 Test kernel livepatching features for correctness. The tests will
2581 load test modules that will be livepatched in various scenarios.
2583 To run all the livepatching tests:
2585 make -C tools/testing/selftests TARGETS=livepatch run_tests
2587 Alternatively, individual tests may be invoked:
2589 tools/testing/selftests/livepatch/test-callbacks.sh
2590 tools/testing/selftests/livepatch/test-livepatch.sh
2591 tools/testing/selftests/livepatch/test-shadow-vars.sh
2596 tristate "Perform selftest on object aggreration manager"
2600 Enable this option to test object aggregation manager on boot
2604 config TEST_STACKINIT
2605 tristate "Test level of stack variable initialization"
2607 Test if the kernel is zero-initializing stack variables and
2608 padding. Coverage is controlled by compiler flags,
2609 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2610 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2615 tristate "Test heap/page initialization"
2617 Test if the kernel is zero-initializing heap and page allocations.
2618 This can be useful to test init_on_alloc and init_on_free features.
2623 tristate "Test HMM (Heterogeneous Memory Management)"
2624 depends on TRANSPARENT_HUGEPAGE
2625 depends on DEVICE_PRIVATE
2629 This is a pseudo device driver solely for testing HMM.
2630 Say M here if you want to build the HMM test module.
2631 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2635 config TEST_FREE_PAGES
2636 tristate "Test freeing pages"
2638 Test that a memory leak does not occur due to a race between
2639 freeing a block of pages and a speculative page reference.
2640 Loading this module is safe if your kernel has the bug fixed.
2641 If the bug is not fixed, it will leak gigabytes of memory and
2642 probably OOM your system.
2645 tristate "Test floating point operations in kernel space"
2646 depends on X86 && !KCOV_INSTRUMENT_ALL
2648 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2649 which will trigger a sequence of floating point operations. This is used
2650 for self-testing floating point control register setting in
2655 config TEST_CLOCKSOURCE_WATCHDOG
2656 tristate "Test clocksource watchdog in kernel space"
2657 depends on CLOCKSOURCE_WATCHDOG
2659 Enable this option to create a kernel module that will trigger
2660 a test of the clocksource watchdog. This module may be loaded
2661 via modprobe or insmod in which case it will run upon being
2662 loaded, or it may be built in, in which case it will run
2667 endif # RUNTIME_TESTING_MENU
2669 config ARCH_USE_MEMTEST
2672 An architecture should select this when it uses early_memtest()
2673 during boot process.
2677 depends on ARCH_USE_MEMTEST
2679 This option adds a kernel parameter 'memtest', which allows memtest
2680 to be set and executed.
2681 memtest=0, mean disabled; -- default
2682 memtest=1, mean do 1 test pattern;
2684 memtest=17, mean do 17 test patterns.
2685 If you are unsure how to answer this question, answer N.
2689 config HYPERV_TESTING
2690 bool "Microsoft Hyper-V driver testing"
2692 depends on HYPERV && DEBUG_FS
2694 Select this option to enable Hyper-V vmbus testing.
2696 endmenu # "Kernel Testing and Coverage"
2698 source "Documentation/Kconfig"
2700 endmenu # Kernel hacking
projects / linux-2.6-microblaze.git / blob