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"
212 bool "Kernel debugging"
214 Say Y here if you are developing drivers or trying to debug and
215 identify kernel problems.
218 bool "Miscellaneous debug code"
220 depends on DEBUG_KERNEL
222 Say Y here if you need to enable miscellaneous debug code that should
223 be under a more specific debug option but isn't.
225 menu "Compile-time checks and compiler options"
230 A kernel debug info option other than "None" has been selected
231 in the "Debug information" choice below, indicating that debug
232 information will be generated for build targets.
234 # Clang is known to generate .{s,u}leb128 with symbol deltas with DWARF5, which
235 # some targets may not support: https://sourceware.org/bugzilla/show_bug.cgi?id=27215
236 config AS_HAS_NON_CONST_LEB128
237 def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:)
240 prompt "Debug information"
241 depends on DEBUG_KERNEL
243 Selecting something other than "None" results in a kernel image
244 that will include debugging info resulting in a larger kernel image.
245 This adds debug symbols to the kernel and modules (gcc -g), and
246 is needed if you intend to use kernel crashdump or binary object
247 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
249 Choose which version of DWARF debug info to emit. If unsure,
250 select "Toolchain default".
252 config DEBUG_INFO_NONE
253 bool "Disable debug information"
255 Do not build the kernel with debugging information, which will
256 result in a faster and smaller build.
258 config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
259 bool "Rely on the toolchain's implicit default DWARF version"
261 depends on !CC_IS_CLANG || AS_IS_LLVM || CLANG_VERSION < 140000 || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128)
263 The implicit default version of DWARF debug info produced by a
264 toolchain changes over time.
266 This can break consumers of the debug info that haven't upgraded to
267 support newer revisions, and prevent testing newer versions, but
268 those should be less common scenarios.
270 config DEBUG_INFO_DWARF4
271 bool "Generate DWARF Version 4 debuginfo"
273 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)
275 Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2
276 if using clang without clang's integrated assembler, and gdb 7.0+.
278 If you have consumers of DWARF debug info that are not ready for
279 newer revisions of DWARF, you may wish to choose this or have your
282 config DEBUG_INFO_DWARF5
283 bool "Generate DWARF Version 5 debuginfo"
285 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128)
287 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
288 5.0+ accepts the -gdwarf-5 flag but only had partial support for some
289 draft features until 7.0), and gdb 8.0+.
291 Changes to the structure of debug info in Version 5 allow for around
292 15-18% savings in resulting image and debug info section sizes as
293 compared to DWARF Version 4. DWARF Version 5 standardizes previous
294 extensions such as accelerators for symbol indexing and the format
295 for fission (.dwo/.dwp) files. Users may not want to select this
296 config if they rely on tooling that has not yet been updated to
297 support DWARF Version 5.
299 endchoice # "Debug information"
303 config DEBUG_INFO_REDUCED
304 bool "Reduce debugging information"
306 If you say Y here gcc is instructed to generate less debugging
307 information for structure types. This means that tools that
308 need full debugging information (like kgdb or systemtap) won't
309 be happy. But if you merely need debugging information to
310 resolve line numbers there is no loss. Advantage is that
311 build directory object sizes shrink dramatically over a full
312 DEBUG_INFO build and compile times are reduced too.
313 Only works with newer gcc versions.
315 config DEBUG_INFO_COMPRESSED
316 bool "Compressed debugging information"
317 depends on $(cc-option,-gz=zlib)
318 depends on $(ld-option,--compress-debug-sections=zlib)
320 Compress the debug information using zlib. Requires GCC 5.0+ or Clang
321 5.0+, binutils 2.26+, and zlib.
323 Users of dpkg-deb via scripts/package/builddeb may find an increase in
324 size of their debug .deb packages with this config set, due to the
325 debug info being compressed with zlib, then the object files being
326 recompressed with a different compression scheme. But this is still
327 preferable to setting $KDEB_COMPRESS to "none" which would be even
330 config DEBUG_INFO_SPLIT
331 bool "Produce split debuginfo in .dwo files"
332 depends on $(cc-option,-gsplit-dwarf)
334 Generate debug info into separate .dwo files. This significantly
335 reduces the build directory size for builds with DEBUG_INFO,
336 because it stores the information only once on disk in .dwo
337 files instead of multiple times in object files and executables.
338 In addition the debug information is also compressed.
340 Requires recent gcc (4.7+) and recent gdb/binutils.
341 Any tool that packages or reads debug information would need
342 to know about the .dwo files and include them.
343 Incompatible with older versions of ccache.
345 config DEBUG_INFO_BTF
346 bool "Generate BTF typeinfo"
347 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
348 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
349 depends on BPF_SYSCALL
350 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121
352 Generate deduplicated BTF type information from DWARF debug info.
353 Turning this on expects presence of pahole tool, which will convert
354 DWARF type info into equivalent deduplicated BTF type info.
356 config PAHOLE_HAS_SPLIT_BTF
357 def_bool PAHOLE_VERSION >= 119
359 config PAHOLE_HAS_BTF_TAG
360 def_bool PAHOLE_VERSION >= 123
361 depends on CC_IS_CLANG
363 Decide whether pahole emits btf_tag attributes (btf_type_tag and
364 btf_decl_tag) or not. Currently only clang compiler implements
365 these attributes, so make the config depend on CC_IS_CLANG.
367 config DEBUG_INFO_BTF_MODULES
369 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
371 Generate compact split BTF type information for kernel modules.
373 config MODULE_ALLOW_BTF_MISMATCH
374 bool "Allow loading modules with non-matching BTF type info"
375 depends on DEBUG_INFO_BTF_MODULES
377 For modules whose split BTF does not match vmlinux, load without
378 BTF rather than refusing to load. The default behavior with
379 module BTF enabled is to reject modules with such mismatches;
380 this option will still load module BTF where possible but ignore
381 it when a mismatch is found.
384 bool "Provide GDB scripts for kernel debugging"
386 This creates the required links to GDB helper scripts in the
387 build directory. If you load vmlinux into gdb, the helper
388 scripts will be automatically imported by gdb as well, and
389 additional functions are available to analyze a Linux kernel
390 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
396 int "Warn for stack frames larger than"
399 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
400 default 2048 if PARISC
401 default 1536 if (!64BIT && XTENSA)
402 default 1280 if KASAN && !64BIT
403 default 1024 if !64BIT
404 default 2048 if 64BIT
406 Tell the compiler to warn at build time for stack frames larger than this.
407 Setting this too low will cause a lot of warnings.
408 Setting it to 0 disables the warning.
410 config STRIP_ASM_SYMS
411 bool "Strip assembler-generated symbols during link"
414 Strip internal assembler-generated symbols during a link (symbols
415 that look like '.Lxxx') so they don't pollute the output of
416 get_wchan() and suchlike.
419 bool "Generate readable assembler code"
420 depends on DEBUG_KERNEL
423 Disable some compiler optimizations that tend to generate human unreadable
424 assembler output. This may make the kernel slightly slower, but it helps
425 to keep kernel developers who have to stare a lot at assembler listings
428 config HEADERS_INSTALL
429 bool "Install uapi headers to usr/include"
432 This option will install uapi headers (headers exported to user-space)
433 into the usr/include directory for use during the kernel build.
434 This is unneeded for building the kernel itself, but needed for some
435 user-space program samples. It is also needed by some features such
436 as uapi header sanity checks.
438 config DEBUG_SECTION_MISMATCH
439 bool "Enable full Section mismatch analysis"
442 The section mismatch analysis checks if there are illegal
443 references from one section to another section.
444 During linktime or runtime, some sections are dropped;
445 any use of code/data previously in these sections would
446 most likely result in an oops.
447 In the code, functions and variables are annotated with
448 __init,, etc. (see the full list in include/linux/init.h),
449 which results in the code/data being placed in specific sections.
450 The section mismatch analysis is always performed after a full
451 kernel build, and enabling this option causes the following
452 additional step to occur:
453 - Add the option -fno-inline-functions-called-once to gcc commands.
454 When inlining a function annotated with __init in a non-init
455 function, we would lose the section information and thus
456 the analysis would not catch the illegal reference.
457 This option tells gcc to inline less (but it does result in
460 config SECTION_MISMATCH_WARN_ONLY
461 bool "Make section mismatch errors non-fatal"
464 If you say N here, the build process will fail if there are any
465 section mismatch, instead of just throwing warnings.
469 config DEBUG_FORCE_FUNCTION_ALIGN_64B
470 bool "Force all function address 64B aligned"
471 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC)
472 select FUNCTION_ALIGNMENT_64B
474 There are cases that a commit from one domain changes the function
475 address alignment of other domains, and cause magic performance
476 bump (regression or improvement). Enable this option will help to
477 verify if the bump is caused by function alignment changes, while
478 it will slightly increase the kernel size and affect icache usage.
480 It is mainly for debug and performance tuning use.
483 # Select this config option from the architecture Kconfig, if it
484 # is preferred to always offer frame pointers as a config
485 # option on the architecture (regardless of KERNEL_DEBUG):
487 config ARCH_WANT_FRAME_POINTERS
491 bool "Compile the kernel with frame pointers"
492 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
493 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
495 If you say Y here the resulting kernel image will be slightly
496 larger and slower, but it gives very useful debugging information
497 in case of kernel bugs. (precise oopses/stacktraces/warnings)
502 config STACK_VALIDATION
503 bool "Compile-time stack metadata validation"
504 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
508 Validate frame pointer rules at compile-time. This helps ensure that
509 runtime stack traces are more reliable.
511 For more information, see
512 tools/objtool/Documentation/objtool.txt.
514 config NOINSTR_VALIDATION
516 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
521 bool "Generate vmlinux.map file when linking"
524 Selecting this option will pass "-Map=vmlinux.map" to ld
525 when linking vmlinux. That file can be useful for verifying
526 and debugging magic section games, and for seeing which
527 pieces of code get eliminated with
528 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
530 config DEBUG_FORCE_WEAK_PER_CPU
531 bool "Force weak per-cpu definitions"
532 depends on DEBUG_KERNEL
534 s390 and alpha require percpu variables in modules to be
535 defined weak to work around addressing range issue which
536 puts the following two restrictions on percpu variable
539 1. percpu symbols must be unique whether static or not
540 2. percpu variables can't be defined inside a function
542 To ensure that generic code follows the above rules, this
543 option forces all percpu variables to be defined as weak.
545 endmenu # "Compiler options"
547 menu "Generic Kernel Debugging Instruments"
550 bool "Magic SysRq key"
553 If you say Y here, you will have some control over the system even
554 if the system crashes for example during kernel debugging (e.g., you
555 will be able to flush the buffer cache to disk, reboot the system
556 immediately or dump some status information). This is accomplished
557 by pressing various keys while holding SysRq (Alt+PrintScreen). It
558 also works on a serial console (on PC hardware at least), if you
559 send a BREAK and then within 5 seconds a command keypress. The
560 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
561 Don't say Y unless you really know what this hack does.
563 config MAGIC_SYSRQ_DEFAULT_ENABLE
564 hex "Enable magic SysRq key functions by default"
565 depends on MAGIC_SYSRQ
568 Specifies which SysRq key functions are enabled by default.
569 This may be set to 1 or 0 to enable or disable them all, or
570 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
572 config MAGIC_SYSRQ_SERIAL
573 bool "Enable magic SysRq key over serial"
574 depends on MAGIC_SYSRQ
577 Many embedded boards have a disconnected TTL level serial which can
578 generate some garbage that can lead to spurious false sysrq detects.
579 This option allows you to decide whether you want to enable the
582 config MAGIC_SYSRQ_SERIAL_SEQUENCE
583 string "Char sequence that enables magic SysRq over serial"
584 depends on MAGIC_SYSRQ_SERIAL
587 Specifies a sequence of characters that can follow BREAK to enable
588 SysRq on a serial console.
590 If unsure, leave an empty string and the option will not be enabled.
593 bool "Debug Filesystem"
595 debugfs is a virtual file system that kernel developers use to put
596 debugging files into. Enable this option to be able to read and
597 write to these files.
599 For detailed documentation on the debugfs API, see
600 Documentation/filesystems/.
605 prompt "Debugfs default access"
607 default DEBUG_FS_ALLOW_ALL
609 This selects the default access restrictions for debugfs.
610 It can be overridden with kernel command line option
611 debugfs=[on,no-mount,off]. The restrictions apply for API access
612 and filesystem registration.
614 config DEBUG_FS_ALLOW_ALL
617 No restrictions apply. Both API and filesystem registration
618 is on. This is the normal default operation.
620 config DEBUG_FS_DISALLOW_MOUNT
621 bool "Do not register debugfs as filesystem"
623 The API is open but filesystem is not loaded. Clients can still do
624 their work and read with debug tools that do not need
627 config DEBUG_FS_ALLOW_NONE
630 Access is off. Clients get -PERM when trying to create nodes in
631 debugfs tree and debugfs is not registered as a filesystem.
632 Client can then back-off or continue without debugfs access.
636 source "lib/Kconfig.kgdb"
637 source "lib/Kconfig.ubsan"
638 source "lib/Kconfig.kcsan"
642 menu "Networking Debugging"
644 source "net/Kconfig.debug"
646 endmenu # "Networking Debugging"
648 menu "Memory Debugging"
650 source "mm/Kconfig.debug"
653 bool "Debug object operations"
654 depends on DEBUG_KERNEL
656 If you say Y here, additional code will be inserted into the
657 kernel to track the life time of various objects and validate
658 the operations on those objects.
660 config DEBUG_OBJECTS_SELFTEST
661 bool "Debug objects selftest"
662 depends on DEBUG_OBJECTS
664 This enables the selftest of the object debug code.
666 config DEBUG_OBJECTS_FREE
667 bool "Debug objects in freed memory"
668 depends on DEBUG_OBJECTS
670 This enables checks whether a k/v free operation frees an area
671 which contains an object which has not been deactivated
672 properly. This can make kmalloc/kfree-intensive workloads
675 config DEBUG_OBJECTS_TIMERS
676 bool "Debug timer objects"
677 depends on DEBUG_OBJECTS
679 If you say Y here, additional code will be inserted into the
680 timer routines to track the life time of timer objects and
681 validate the timer operations.
683 config DEBUG_OBJECTS_WORK
684 bool "Debug work objects"
685 depends on DEBUG_OBJECTS
687 If you say Y here, additional code will be inserted into the
688 work queue routines to track the life time of work objects and
689 validate the work operations.
691 config DEBUG_OBJECTS_RCU_HEAD
692 bool "Debug RCU callbacks objects"
693 depends on DEBUG_OBJECTS
695 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
697 config DEBUG_OBJECTS_PERCPU_COUNTER
698 bool "Debug percpu counter objects"
699 depends on DEBUG_OBJECTS
701 If you say Y here, additional code will be inserted into the
702 percpu counter routines to track the life time of percpu counter
703 objects and validate the percpu counter operations.
705 config DEBUG_OBJECTS_ENABLE_DEFAULT
706 int "debug_objects bootup default value (0-1)"
709 depends on DEBUG_OBJECTS
711 Debug objects boot parameter default value
713 config SHRINKER_DEBUG
714 bool "Enable shrinker debugging support"
717 Say Y to enable the shrinker debugfs interface which provides
718 visibility into the kernel memory shrinkers subsystem.
719 Disable it to avoid an extra memory footprint.
721 config HAVE_DEBUG_KMEMLEAK
724 config DEBUG_KMEMLEAK
725 bool "Kernel memory leak detector"
726 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
728 select STACKTRACE if STACKTRACE_SUPPORT
732 Say Y here if you want to enable the memory leak
733 detector. The memory allocation/freeing is traced in a way
734 similar to the Boehm's conservative garbage collector, the
735 difference being that the orphan objects are not freed but
736 only shown in /sys/kernel/debug/kmemleak. Enabling this
737 feature will introduce an overhead to memory
738 allocations. See Documentation/dev-tools/kmemleak.rst for more
741 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
742 of finding leaks due to the slab objects poisoning.
744 In order to access the kmemleak file, debugfs needs to be
745 mounted (usually at /sys/kernel/debug).
747 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
748 int "Kmemleak memory pool size"
749 depends on DEBUG_KMEMLEAK
753 Kmemleak must track all the memory allocations to avoid
754 reporting false positives. Since memory may be allocated or
755 freed before kmemleak is fully initialised, use a static pool
756 of metadata objects to track such callbacks. After kmemleak is
757 fully initialised, this memory pool acts as an emergency one
758 if slab allocations fail.
760 config DEBUG_KMEMLEAK_TEST
761 tristate "Simple test for the kernel memory leak detector"
762 depends on DEBUG_KMEMLEAK && m
764 This option enables a module that explicitly leaks memory.
768 config DEBUG_KMEMLEAK_DEFAULT_OFF
769 bool "Default kmemleak to off"
770 depends on DEBUG_KMEMLEAK
772 Say Y here to disable kmemleak by default. It can then be enabled
773 on the command line via kmemleak=on.
775 config DEBUG_KMEMLEAK_AUTO_SCAN
776 bool "Enable kmemleak auto scan thread on boot up"
778 depends on DEBUG_KMEMLEAK
780 Depending on the cpu, kmemleak scan may be cpu intensive and can
781 stall user tasks at times. This option enables/disables automatic
782 kmemleak scan at boot up.
784 Say N here to disable kmemleak auto scan thread to stop automatic
785 scanning. Disabling this option disables automatic reporting of
790 config DEBUG_STACK_USAGE
791 bool "Stack utilization instrumentation"
792 depends on DEBUG_KERNEL && !IA64
794 Enables the display of the minimum amount of free stack which each
795 task has ever had available in the sysrq-T and sysrq-P debug output.
797 This option will slow down process creation somewhat.
799 config SCHED_STACK_END_CHECK
800 bool "Detect stack corruption on calls to schedule()"
801 depends on DEBUG_KERNEL
804 This option checks for a stack overrun on calls to schedule().
805 If the stack end location is found to be over written always panic as
806 the content of the corrupted region can no longer be trusted.
807 This is to ensure no erroneous behaviour occurs which could result in
808 data corruption or a sporadic crash at a later stage once the region
809 is examined. The runtime overhead introduced is minimal.
811 config ARCH_HAS_DEBUG_VM_PGTABLE
814 An architecture should select this when it can successfully
815 build and run DEBUG_VM_PGTABLE.
817 config DEBUG_VM_IRQSOFF
818 def_bool DEBUG_VM && !PREEMPT_RT
822 depends on DEBUG_KERNEL
824 Enable this to turn on extended checks in the virtual-memory system
825 that may impact performance.
829 config DEBUG_VM_MAPLE_TREE
830 bool "Debug VM maple trees"
832 select DEBUG_MAPLE_TREE
834 Enable VM maple tree debugging information and extra validations.
839 bool "Debug VM red-black trees"
842 Enable VM red-black tree debugging information and extra validations.
846 config DEBUG_VM_PGFLAGS
847 bool "Debug page-flags operations"
850 Enables extra validation on page flags operations.
854 config DEBUG_VM_PGTABLE
855 bool "Debug arch page table for semantics compliance"
857 depends on ARCH_HAS_DEBUG_VM_PGTABLE
858 default y if DEBUG_VM
860 This option provides a debug method which can be used to test
861 architecture page table helper functions on various platforms in
862 verifying if they comply with expected generic MM semantics. This
863 will help architecture code in making sure that any changes or
864 new additions of these helpers still conform to expected
865 semantics of the generic MM. Platforms will have to opt in for
866 this through ARCH_HAS_DEBUG_VM_PGTABLE.
870 config ARCH_HAS_DEBUG_VIRTUAL
874 bool "Debug VM translations"
875 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
877 Enable some costly sanity checks in virtual to page code. This can
878 catch mistakes with virt_to_page() and friends.
882 config DEBUG_NOMMU_REGIONS
883 bool "Debug the global anon/private NOMMU mapping region tree"
884 depends on DEBUG_KERNEL && !MMU
886 This option causes the global tree of anonymous and private mapping
887 regions to be regularly checked for invalid topology.
889 config DEBUG_MEMORY_INIT
890 bool "Debug memory initialisation" if EXPERT
893 Enable this for additional checks during memory initialisation.
894 The sanity checks verify aspects of the VM such as the memory model
895 and other information provided by the architecture. Verbose
896 information will be printed at KERN_DEBUG loglevel depending
897 on the mminit_loglevel= command-line option.
901 config MEMORY_NOTIFIER_ERROR_INJECT
902 tristate "Memory hotplug notifier error injection module"
903 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
905 This option provides the ability to inject artificial errors to
906 memory hotplug notifier chain callbacks. It is controlled through
907 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
909 If the notifier call chain should be failed with some events
910 notified, write the error code to "actions/<notifier event>/error".
912 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
914 # cd /sys/kernel/debug/notifier-error-inject/memory
915 # echo -12 > actions/MEM_GOING_OFFLINE/error
916 # echo offline > /sys/devices/system/memory/memoryXXX/state
917 bash: echo: write error: Cannot allocate memory
919 To compile this code as a module, choose M here: the module will
920 be called memory-notifier-error-inject.
924 config DEBUG_PER_CPU_MAPS
925 bool "Debug access to per_cpu maps"
926 depends on DEBUG_KERNEL
929 Say Y to verify that the per_cpu map being accessed has
930 been set up. This adds a fair amount of code to kernel memory
931 and decreases performance.
935 config DEBUG_KMAP_LOCAL
936 bool "Debug kmap_local temporary mappings"
937 depends on DEBUG_KERNEL && KMAP_LOCAL
939 This option enables additional error checking for the kmap_local
940 infrastructure. Disable for production use.
942 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
945 config DEBUG_KMAP_LOCAL_FORCE_MAP
946 bool "Enforce kmap_local temporary mappings"
947 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
949 select DEBUG_KMAP_LOCAL
951 This option enforces temporary mappings through the kmap_local
952 mechanism for non-highmem pages and on non-highmem systems.
953 Disable this for production systems!
956 bool "Highmem debugging"
957 depends on DEBUG_KERNEL && HIGHMEM
958 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
959 select DEBUG_KMAP_LOCAL
961 This option enables additional error checking for high memory
962 systems. Disable for production systems.
964 config HAVE_DEBUG_STACKOVERFLOW
967 config DEBUG_STACKOVERFLOW
968 bool "Check for stack overflows"
969 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
971 Say Y here if you want to check for overflows of kernel, IRQ
972 and exception stacks (if your architecture uses them). This
973 option will show detailed messages if free stack space drops
974 below a certain limit.
976 These kinds of bugs usually occur when call-chains in the
977 kernel get too deep, especially when interrupts are
980 Use this in cases where you see apparently random memory
981 corruption, especially if it appears in 'struct thread_info'
983 If in doubt, say "N".
985 source "lib/Kconfig.kasan"
986 source "lib/Kconfig.kfence"
987 source "lib/Kconfig.kmsan"
989 endmenu # "Memory Debugging"
992 bool "Debug shared IRQ handlers"
993 depends on DEBUG_KERNEL
995 Enable this to generate a spurious interrupt just before a shared
996 interrupt handler is deregistered (generating one when registering
997 is currently disabled). Drivers need to handle this correctly. Some
998 don't and need to be caught.
1000 menu "Debug Oops, Lockups and Hangs"
1002 config PANIC_ON_OOPS
1003 bool "Panic on Oops"
1005 Say Y here to enable the kernel to panic when it oopses. This
1006 has the same effect as setting oops=panic on the kernel command
1009 This feature is useful to ensure that the kernel does not do
1010 anything erroneous after an oops which could result in data
1011 corruption or other issues.
1015 config PANIC_ON_OOPS_VALUE
1018 default 0 if !PANIC_ON_OOPS
1019 default 1 if PANIC_ON_OOPS
1021 config PANIC_TIMEOUT
1025 Set the timeout value (in seconds) until a reboot occurs when
1026 the kernel panics. If n = 0, then we wait forever. A timeout
1027 value n > 0 will wait n seconds before rebooting, while a timeout
1028 value n < 0 will reboot immediately.
1030 config LOCKUP_DETECTOR
1033 config SOFTLOCKUP_DETECTOR
1034 bool "Detect Soft Lockups"
1035 depends on DEBUG_KERNEL && !S390
1036 select LOCKUP_DETECTOR
1038 Say Y here to enable the kernel to act as a watchdog to detect
1041 Softlockups are bugs that cause the kernel to loop in kernel
1042 mode for more than 20 seconds, without giving other tasks a
1043 chance to run. The current stack trace is displayed upon
1044 detection and the system will stay locked up.
1046 config BOOTPARAM_SOFTLOCKUP_PANIC
1047 bool "Panic (Reboot) On Soft Lockups"
1048 depends on SOFTLOCKUP_DETECTOR
1050 Say Y here to enable the kernel to panic on "soft lockups",
1051 which are bugs that cause the kernel to loop in kernel
1052 mode for more than 20 seconds (configurable using the watchdog_thresh
1053 sysctl), without giving other tasks a chance to run.
1055 The panic can be used in combination with panic_timeout,
1056 to cause the system to reboot automatically after a
1057 lockup has been detected. This feature is useful for
1058 high-availability systems that have uptime guarantees and
1059 where a lockup must be resolved ASAP.
1063 config HARDLOCKUP_DETECTOR_PERF
1065 select SOFTLOCKUP_DETECTOR
1068 # Enables a timestamp based low pass filter to compensate for perf based
1069 # hard lockup detection which runs too fast due to turbo modes.
1071 config HARDLOCKUP_CHECK_TIMESTAMP
1075 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1076 # lockup detector rather than the perf based detector.
1078 config HARDLOCKUP_DETECTOR
1079 bool "Detect Hard Lockups"
1080 depends on DEBUG_KERNEL && !S390
1081 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1082 select LOCKUP_DETECTOR
1083 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1085 Say Y here to enable the kernel to act as a watchdog to detect
1088 Hardlockups are bugs that cause the CPU to loop in kernel mode
1089 for more than 10 seconds, without letting other interrupts have a
1090 chance to run. The current stack trace is displayed upon detection
1091 and the system will stay locked up.
1093 config BOOTPARAM_HARDLOCKUP_PANIC
1094 bool "Panic (Reboot) On Hard Lockups"
1095 depends on HARDLOCKUP_DETECTOR
1097 Say Y here to enable the kernel to panic on "hard lockups",
1098 which are bugs that cause the kernel to loop in kernel
1099 mode with interrupts disabled for more than 10 seconds (configurable
1100 using the watchdog_thresh sysctl).
1104 config DETECT_HUNG_TASK
1105 bool "Detect Hung Tasks"
1106 depends on DEBUG_KERNEL
1107 default SOFTLOCKUP_DETECTOR
1109 Say Y here to enable the kernel to detect "hung tasks",
1110 which are bugs that cause the task to be stuck in
1111 uninterruptible "D" state indefinitely.
1113 When a hung task is detected, the kernel will print the
1114 current stack trace (which you should report), but the
1115 task will stay in uninterruptible state. If lockdep is
1116 enabled then all held locks will also be reported. This
1117 feature has negligible overhead.
1119 config DEFAULT_HUNG_TASK_TIMEOUT
1120 int "Default timeout for hung task detection (in seconds)"
1121 depends on DETECT_HUNG_TASK
1124 This option controls the default timeout (in seconds) used
1125 to determine when a task has become non-responsive and should
1128 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1129 sysctl or by writing a value to
1130 /proc/sys/kernel/hung_task_timeout_secs.
1132 A timeout of 0 disables the check. The default is two minutes.
1133 Keeping the default should be fine in most cases.
1135 config BOOTPARAM_HUNG_TASK_PANIC
1136 bool "Panic (Reboot) On Hung Tasks"
1137 depends on DETECT_HUNG_TASK
1139 Say Y here to enable the kernel to panic on "hung tasks",
1140 which are bugs that cause the kernel to leave a task stuck
1141 in uninterruptible "D" state.
1143 The panic can be used in combination with panic_timeout,
1144 to cause the system to reboot automatically after a
1145 hung task has been detected. This feature is useful for
1146 high-availability systems that have uptime guarantees and
1147 where a hung tasks must be resolved ASAP.
1152 bool "Detect Workqueue Stalls"
1153 depends on DEBUG_KERNEL
1155 Say Y here to enable stall detection on workqueues. If a
1156 worker pool doesn't make forward progress on a pending work
1157 item for over a given amount of time, 30s by default, a
1158 warning message is printed along with dump of workqueue
1159 state. This can be configured through kernel parameter
1160 "workqueue.watchdog_thresh" and its sysfs counterpart.
1163 tristate "Test module to generate lockups"
1166 This builds the "test_lockup" module that helps to make sure
1167 that watchdogs and lockup detectors are working properly.
1169 Depending on module parameters it could emulate soft or hard
1170 lockup, "hung task", or locking arbitrary lock for a long time.
1171 Also it could generate series of lockups with cooling-down periods.
1175 endmenu # "Debug lockups and hangs"
1177 menu "Scheduler Debugging"
1180 bool "Collect scheduler debugging info"
1181 depends on DEBUG_KERNEL && PROC_FS
1184 If you say Y here, the /proc/sched_debug file will be provided
1185 that can help debug the scheduler. The runtime overhead of this
1193 bool "Collect scheduler statistics"
1194 depends on DEBUG_KERNEL && PROC_FS
1197 If you say Y here, additional code will be inserted into the
1198 scheduler and related routines to collect statistics about
1199 scheduler behavior and provide them in /proc/schedstat. These
1200 stats may be useful for both tuning and debugging the scheduler
1201 If you aren't debugging the scheduler or trying to tune a specific
1202 application, you can say N to avoid the very slight overhead
1207 config DEBUG_TIMEKEEPING
1208 bool "Enable extra timekeeping sanity checking"
1210 This option will enable additional timekeeping sanity checks
1211 which may be helpful when diagnosing issues where timekeeping
1212 problems are suspected.
1214 This may include checks in the timekeeping hotpaths, so this
1215 option may have a (very small) performance impact to some
1220 config DEBUG_PREEMPT
1221 bool "Debug preemptible kernel"
1222 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1225 If you say Y here then the kernel will use a debug variant of the
1226 commonly used smp_processor_id() function and will print warnings
1227 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1228 will detect preemption count underflows.
1230 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1232 config LOCK_DEBUGGING_SUPPORT
1234 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1237 config PROVE_LOCKING
1238 bool "Lock debugging: prove locking correctness"
1239 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1241 select DEBUG_SPINLOCK
1242 select DEBUG_MUTEXES if !PREEMPT_RT
1243 select DEBUG_RT_MUTEXES if RT_MUTEXES
1245 select DEBUG_WW_MUTEX_SLOWPATH
1246 select DEBUG_LOCK_ALLOC
1247 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1248 select TRACE_IRQFLAGS
1251 This feature enables the kernel to prove that all locking
1252 that occurs in the kernel runtime is mathematically
1253 correct: that under no circumstance could an arbitrary (and
1254 not yet triggered) combination of observed locking
1255 sequences (on an arbitrary number of CPUs, running an
1256 arbitrary number of tasks and interrupt contexts) cause a
1259 In short, this feature enables the kernel to report locking
1260 related deadlocks before they actually occur.
1262 The proof does not depend on how hard and complex a
1263 deadlock scenario would be to trigger: how many
1264 participant CPUs, tasks and irq-contexts would be needed
1265 for it to trigger. The proof also does not depend on
1266 timing: if a race and a resulting deadlock is possible
1267 theoretically (no matter how unlikely the race scenario
1268 is), it will be proven so and will immediately be
1269 reported by the kernel (once the event is observed that
1270 makes the deadlock theoretically possible).
1272 If a deadlock is impossible (i.e. the locking rules, as
1273 observed by the kernel, are mathematically correct), the
1274 kernel reports nothing.
1276 NOTE: this feature can also be enabled for rwlocks, mutexes
1277 and rwsems - in which case all dependencies between these
1278 different locking variants are observed and mapped too, and
1279 the proof of observed correctness is also maintained for an
1280 arbitrary combination of these separate locking variants.
1282 For more details, see Documentation/locking/lockdep-design.rst.
1284 config PROVE_RAW_LOCK_NESTING
1285 bool "Enable raw_spinlock - spinlock nesting checks"
1286 depends on PROVE_LOCKING
1289 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1290 that the lock nesting rules for PREEMPT_RT enabled kernels are
1293 NOTE: There are known nesting problems. So if you enable this
1294 option expect lockdep splats until these problems have been fully
1295 addressed which is work in progress. This config switch allows to
1296 identify and analyze these problems. It will be removed and the
1297 check permanently enabled once the main issues have been fixed.
1299 If unsure, select N.
1302 bool "Lock usage statistics"
1303 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1305 select DEBUG_SPINLOCK
1306 select DEBUG_MUTEXES if !PREEMPT_RT
1307 select DEBUG_RT_MUTEXES if RT_MUTEXES
1308 select DEBUG_LOCK_ALLOC
1311 This feature enables tracking lock contention points
1313 For more details, see Documentation/locking/lockstat.rst
1315 This also enables lock events required by "perf lock",
1317 If you want to use "perf lock", you also need to turn on
1318 CONFIG_EVENT_TRACING.
1320 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1321 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1323 config DEBUG_RT_MUTEXES
1324 bool "RT Mutex debugging, deadlock detection"
1325 depends on DEBUG_KERNEL && RT_MUTEXES
1327 This allows rt mutex semantics violations and rt mutex related
1328 deadlocks (lockups) to be detected and reported automatically.
1330 config DEBUG_SPINLOCK
1331 bool "Spinlock and rw-lock debugging: basic checks"
1332 depends on DEBUG_KERNEL
1333 select UNINLINE_SPIN_UNLOCK
1335 Say Y here and build SMP to catch missing spinlock initialization
1336 and certain other kinds of spinlock errors commonly made. This is
1337 best used in conjunction with the NMI watchdog so that spinlock
1338 deadlocks are also debuggable.
1340 config DEBUG_MUTEXES
1341 bool "Mutex debugging: basic checks"
1342 depends on DEBUG_KERNEL && !PREEMPT_RT
1344 This feature allows mutex semantics violations to be detected and
1347 config DEBUG_WW_MUTEX_SLOWPATH
1348 bool "Wait/wound mutex debugging: Slowpath testing"
1349 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1350 select DEBUG_LOCK_ALLOC
1351 select DEBUG_SPINLOCK
1352 select DEBUG_MUTEXES if !PREEMPT_RT
1353 select DEBUG_RT_MUTEXES if PREEMPT_RT
1355 This feature enables slowpath testing for w/w mutex users by
1356 injecting additional -EDEADLK wound/backoff cases. Together with
1357 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1358 will test all possible w/w mutex interface abuse with the
1359 exception of simply not acquiring all the required locks.
1360 Note that this feature can introduce significant overhead, so
1361 it really should not be enabled in a production or distro kernel,
1362 even a debug kernel. If you are a driver writer, enable it. If
1363 you are a distro, do not.
1366 bool "RW Semaphore debugging: basic checks"
1367 depends on DEBUG_KERNEL
1369 This debugging feature allows mismatched rw semaphore locks
1370 and unlocks to be detected and reported.
1372 config DEBUG_LOCK_ALLOC
1373 bool "Lock debugging: detect incorrect freeing of live locks"
1374 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1375 select DEBUG_SPINLOCK
1376 select DEBUG_MUTEXES if !PREEMPT_RT
1377 select DEBUG_RT_MUTEXES if RT_MUTEXES
1380 This feature will check whether any held lock (spinlock, rwlock,
1381 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1382 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1383 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1384 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1385 held during task exit.
1389 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1394 config LOCKDEP_SMALL
1398 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1399 depends on LOCKDEP && !LOCKDEP_SMALL
1403 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1405 config LOCKDEP_CHAINS_BITS
1406 int "Bitsize for MAX_LOCKDEP_CHAINS"
1407 depends on LOCKDEP && !LOCKDEP_SMALL
1411 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1413 config LOCKDEP_STACK_TRACE_BITS
1414 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1415 depends on LOCKDEP && !LOCKDEP_SMALL
1419 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1421 config LOCKDEP_STACK_TRACE_HASH_BITS
1422 int "Bitsize for STACK_TRACE_HASH_SIZE"
1423 depends on LOCKDEP && !LOCKDEP_SMALL
1427 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1429 config LOCKDEP_CIRCULAR_QUEUE_BITS
1430 int "Bitsize for elements in circular_queue struct"
1435 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1437 config DEBUG_LOCKDEP
1438 bool "Lock dependency engine debugging"
1439 depends on DEBUG_KERNEL && LOCKDEP
1440 select DEBUG_IRQFLAGS
1442 If you say Y here, the lock dependency engine will do
1443 additional runtime checks to debug itself, at the price
1444 of more runtime overhead.
1446 config DEBUG_ATOMIC_SLEEP
1447 bool "Sleep inside atomic section checking"
1448 select PREEMPT_COUNT
1449 depends on DEBUG_KERNEL
1450 depends on !ARCH_NO_PREEMPT
1452 If you say Y here, various routines which may sleep will become very
1453 noisy if they are called inside atomic sections: when a spinlock is
1454 held, inside an rcu read side critical section, inside preempt disabled
1455 sections, inside an interrupt, etc...
1457 config DEBUG_LOCKING_API_SELFTESTS
1458 bool "Locking API boot-time self-tests"
1459 depends on DEBUG_KERNEL
1461 Say Y here if you want the kernel to run a short self-test during
1462 bootup. The self-test checks whether common types of locking bugs
1463 are detected by debugging mechanisms or not. (if you disable
1464 lock debugging then those bugs won't be detected of course.)
1465 The following locking APIs are covered: spinlocks, rwlocks,
1468 config LOCK_TORTURE_TEST
1469 tristate "torture tests for locking"
1470 depends on DEBUG_KERNEL
1473 This option provides a kernel module that runs torture tests
1474 on kernel locking primitives. The kernel module may be built
1475 after the fact on the running kernel to be tested, if desired.
1477 Say Y here if you want kernel locking-primitive torture tests
1478 to be built into the kernel.
1479 Say M if you want these torture tests to build as a module.
1480 Say N if you are unsure.
1482 config WW_MUTEX_SELFTEST
1483 tristate "Wait/wound mutex selftests"
1485 This option provides a kernel module that runs tests on the
1486 on the struct ww_mutex locking API.
1488 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1489 with this test harness.
1491 Say M if you want these self tests to build as a module.
1492 Say N if you are unsure.
1494 config SCF_TORTURE_TEST
1495 tristate "torture tests for smp_call_function*()"
1496 depends on DEBUG_KERNEL
1499 This option provides a kernel module that runs torture tests
1500 on the smp_call_function() family of primitives. The kernel
1501 module may be built after the fact on the running kernel to
1502 be tested, if desired.
1504 config CSD_LOCK_WAIT_DEBUG
1505 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1506 depends on DEBUG_KERNEL
1510 This option enables debug prints when CPUs are slow to respond
1511 to the smp_call_function*() IPI wrappers. These debug prints
1512 include the IPI handler function currently executing (if any)
1513 and relevant stack traces.
1515 endmenu # lock debugging
1517 config TRACE_IRQFLAGS
1518 depends on TRACE_IRQFLAGS_SUPPORT
1521 Enables hooks to interrupt enabling and disabling for
1522 either tracing or lock debugging.
1524 config TRACE_IRQFLAGS_NMI
1526 depends on TRACE_IRQFLAGS
1527 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1529 config DEBUG_IRQFLAGS
1530 bool "Debug IRQ flag manipulation"
1532 Enables checks for potentially unsafe enabling or disabling of
1533 interrupts, such as calling raw_local_irq_restore() when interrupts
1537 bool "Stack backtrace support"
1538 depends on STACKTRACE_SUPPORT
1540 This option causes the kernel to create a /proc/pid/stack for
1541 every process, showing its current stack trace.
1542 It is also used by various kernel debugging features that require
1543 stack trace generation.
1545 config WARN_ALL_UNSEEDED_RANDOM
1546 bool "Warn for all uses of unseeded randomness"
1549 Some parts of the kernel contain bugs relating to their use of
1550 cryptographically secure random numbers before it's actually possible
1551 to generate those numbers securely. This setting ensures that these
1552 flaws don't go unnoticed, by enabling a message, should this ever
1553 occur. This will allow people with obscure setups to know when things
1554 are going wrong, so that they might contact developers about fixing
1557 Unfortunately, on some models of some architectures getting
1558 a fully seeded CRNG is extremely difficult, and so this can
1559 result in dmesg getting spammed for a surprisingly long
1560 time. This is really bad from a security perspective, and
1561 so architecture maintainers really need to do what they can
1562 to get the CRNG seeded sooner after the system is booted.
1563 However, since users cannot do anything actionable to
1564 address this, by default this option is disabled.
1566 Say Y here if you want to receive warnings for all uses of
1567 unseeded randomness. This will be of use primarily for
1568 those developers interested in improving the security of
1569 Linux kernels running on their architecture (or
1572 config DEBUG_KOBJECT
1573 bool "kobject debugging"
1574 depends on DEBUG_KERNEL
1576 If you say Y here, some extra kobject debugging messages will be sent
1579 config DEBUG_KOBJECT_RELEASE
1580 bool "kobject release debugging"
1581 depends on DEBUG_OBJECTS_TIMERS
1583 kobjects are reference counted objects. This means that their
1584 last reference count put is not predictable, and the kobject can
1585 live on past the point at which a driver decides to drop its
1586 initial reference to the kobject gained on allocation. An
1587 example of this would be a struct device which has just been
1590 However, some buggy drivers assume that after such an operation,
1591 the memory backing the kobject can be immediately freed. This
1592 goes completely against the principles of a refcounted object.
1594 If you say Y here, the kernel will delay the release of kobjects
1595 on the last reference count to improve the visibility of this
1596 kind of kobject release bug.
1598 config HAVE_DEBUG_BUGVERBOSE
1601 menu "Debug kernel data structures"
1604 bool "Debug linked list manipulation"
1605 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1607 Enable this to turn on extended checks in the linked-list
1613 bool "Debug priority linked list manipulation"
1614 depends on DEBUG_KERNEL
1616 Enable this to turn on extended checks in the priority-ordered
1617 linked-list (plist) walking routines. This checks the entire
1618 list multiple times during each manipulation.
1623 bool "Debug SG table operations"
1624 depends on DEBUG_KERNEL
1626 Enable this to turn on checks on scatter-gather tables. This can
1627 help find problems with drivers that do not properly initialize
1632 config DEBUG_NOTIFIERS
1633 bool "Debug notifier call chains"
1634 depends on DEBUG_KERNEL
1636 Enable this to turn on sanity checking for notifier call chains.
1637 This is most useful for kernel developers to make sure that
1638 modules properly unregister themselves from notifier chains.
1639 This is a relatively cheap check but if you care about maximum
1642 config BUG_ON_DATA_CORRUPTION
1643 bool "Trigger a BUG when data corruption is detected"
1646 Select this option if the kernel should BUG when it encounters
1647 data corruption in kernel memory structures when they get checked
1652 config DEBUG_MAPLE_TREE
1653 bool "Debug maple trees"
1654 depends on DEBUG_KERNEL
1656 Enable maple tree debugging information and extra validations.
1662 config DEBUG_CREDENTIALS
1663 bool "Debug credential management"
1664 depends on DEBUG_KERNEL
1666 Enable this to turn on some debug checking for credential
1667 management. The additional code keeps track of the number of
1668 pointers from task_structs to any given cred struct, and checks to
1669 see that this number never exceeds the usage count of the cred
1672 Furthermore, if SELinux is enabled, this also checks that the
1673 security pointer in the cred struct is never seen to be invalid.
1677 source "kernel/rcu/Kconfig.debug"
1679 config DEBUG_WQ_FORCE_RR_CPU
1680 bool "Force round-robin CPU selection for unbound work items"
1681 depends on DEBUG_KERNEL
1684 Workqueue used to implicitly guarantee that work items queued
1685 without explicit CPU specified are put on the local CPU. This
1686 guarantee is no longer true and while local CPU is still
1687 preferred work items may be put on foreign CPUs. Kernel
1688 parameter "workqueue.debug_force_rr_cpu" is added to force
1689 round-robin CPU selection to flush out usages which depend on the
1690 now broken guarantee. This config option enables the debug
1691 feature by default. When enabled, memory and cache locality will
1694 config CPU_HOTPLUG_STATE_CONTROL
1695 bool "Enable CPU hotplug state control"
1696 depends on DEBUG_KERNEL
1697 depends on HOTPLUG_CPU
1700 Allows to write steps between "offline" and "online" to the CPUs
1701 sysfs target file so states can be stepped granular. This is a debug
1702 option for now as the hotplug machinery cannot be stopped and
1703 restarted at arbitrary points yet.
1705 Say N if your are unsure.
1708 bool "Latency measuring infrastructure"
1709 depends on DEBUG_KERNEL
1710 depends on STACKTRACE_SUPPORT
1712 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1718 Enable this option if you want to use the LatencyTOP tool
1719 to find out which userspace is blocking on what kernel operations.
1721 config DEBUG_CGROUP_REF
1722 bool "Disable inlining of cgroup css reference count functions"
1723 depends on DEBUG_KERNEL
1728 Force cgroup css reference count functions to not be inlined so
1729 that they can be kprobed for debugging.
1731 source "kernel/trace/Kconfig"
1733 config PROVIDE_OHCI1394_DMA_INIT
1734 bool "Remote debugging over FireWire early on boot"
1735 depends on PCI && X86
1737 If you want to debug problems which hang or crash the kernel early
1738 on boot and the crashing machine has a FireWire port, you can use
1739 this feature to remotely access the memory of the crashed machine
1740 over FireWire. This employs remote DMA as part of the OHCI1394
1741 specification which is now the standard for FireWire controllers.
1743 With remote DMA, you can monitor the printk buffer remotely using
1744 firescope and access all memory below 4GB using fireproxy from gdb.
1745 Even controlling a kernel debugger is possible using remote DMA.
1749 If ohci1394_dma=early is used as boot parameter, it will initialize
1750 all OHCI1394 controllers which are found in the PCI config space.
1752 As all changes to the FireWire bus such as enabling and disabling
1753 devices cause a bus reset and thereby disable remote DMA for all
1754 devices, be sure to have the cable plugged and FireWire enabled on
1755 the debugging host before booting the debug target for debugging.
1757 This code (~1k) is freed after boot. By then, the firewire stack
1758 in charge of the OHCI-1394 controllers should be used instead.
1760 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1762 source "samples/Kconfig"
1764 config ARCH_HAS_DEVMEM_IS_ALLOWED
1767 config STRICT_DEVMEM
1768 bool "Filter access to /dev/mem"
1769 depends on MMU && DEVMEM
1770 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1771 default y if PPC || X86 || ARM64
1773 If this option is disabled, you allow userspace (root) access to all
1774 of memory, including kernel and userspace memory. Accidental
1775 access to this is obviously disastrous, but specific access can
1776 be used by people debugging the kernel. Note that with PAT support
1777 enabled, even in this case there are restrictions on /dev/mem
1778 use due to the cache aliasing requirements.
1780 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1781 file only allows userspace access to PCI space and the BIOS code and
1782 data regions. This is sufficient for dosemu and X and all common
1787 config IO_STRICT_DEVMEM
1788 bool "Filter I/O access to /dev/mem"
1789 depends on STRICT_DEVMEM
1791 If this option is disabled, you allow userspace (root) access to all
1792 io-memory regardless of whether a driver is actively using that
1793 range. Accidental access to this is obviously disastrous, but
1794 specific access can be used by people debugging kernel drivers.
1796 If this option is switched on, the /dev/mem file only allows
1797 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1798 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1799 if the driver using a given range cannot be disabled.
1803 menu "$(SRCARCH) Debugging"
1805 source "arch/$(SRCARCH)/Kconfig.debug"
1809 menu "Kernel Testing and Coverage"
1811 source "lib/kunit/Kconfig"
1813 config NOTIFIER_ERROR_INJECTION
1814 tristate "Notifier error injection"
1815 depends on DEBUG_KERNEL
1818 This option provides the ability to inject artificial errors to
1819 specified notifier chain callbacks. It is useful to test the error
1820 handling of notifier call chain failures.
1824 config PM_NOTIFIER_ERROR_INJECT
1825 tristate "PM notifier error injection module"
1826 depends on PM && NOTIFIER_ERROR_INJECTION
1827 default m if PM_DEBUG
1829 This option provides the ability to inject artificial errors to
1830 PM notifier chain callbacks. It is controlled through debugfs
1831 interface /sys/kernel/debug/notifier-error-inject/pm
1833 If the notifier call chain should be failed with some events
1834 notified, write the error code to "actions/<notifier event>/error".
1836 Example: Inject PM suspend error (-12 = -ENOMEM)
1838 # cd /sys/kernel/debug/notifier-error-inject/pm/
1839 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1840 # echo mem > /sys/power/state
1841 bash: echo: write error: Cannot allocate memory
1843 To compile this code as a module, choose M here: the module will
1844 be called pm-notifier-error-inject.
1848 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1849 tristate "OF reconfig notifier error injection module"
1850 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1852 This option provides the ability to inject artificial errors to
1853 OF reconfig notifier chain callbacks. It is controlled
1854 through debugfs interface under
1855 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1857 If the notifier call chain should be failed with some events
1858 notified, write the error code to "actions/<notifier event>/error".
1860 To compile this code as a module, choose M here: the module will
1861 be called of-reconfig-notifier-error-inject.
1865 config NETDEV_NOTIFIER_ERROR_INJECT
1866 tristate "Netdev notifier error injection module"
1867 depends on NET && NOTIFIER_ERROR_INJECTION
1869 This option provides the ability to inject artificial errors to
1870 netdevice notifier chain callbacks. It is controlled through debugfs
1871 interface /sys/kernel/debug/notifier-error-inject/netdev
1873 If the notifier call chain should be failed with some events
1874 notified, write the error code to "actions/<notifier event>/error".
1876 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1878 # cd /sys/kernel/debug/notifier-error-inject/netdev
1879 # echo -22 > actions/NETDEV_CHANGEMTU/error
1880 # ip link set eth0 mtu 1024
1881 RTNETLINK answers: Invalid argument
1883 To compile this code as a module, choose M here: the module will
1884 be called netdev-notifier-error-inject.
1888 config FUNCTION_ERROR_INJECTION
1889 bool "Fault-injections of functions"
1890 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1892 Add fault injections into various functions that are annotated with
1893 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
1894 value of theses functions. This is useful to test error paths of code.
1898 config FAULT_INJECTION
1899 bool "Fault-injection framework"
1900 depends on DEBUG_KERNEL
1902 Provide fault-injection framework.
1903 For more details, see Documentation/fault-injection/.
1906 bool "Fault-injection capability for kmalloc"
1907 depends on FAULT_INJECTION
1908 depends on SLAB || SLUB
1910 Provide fault-injection capability for kmalloc.
1912 config FAIL_PAGE_ALLOC
1913 bool "Fault-injection capability for alloc_pages()"
1914 depends on FAULT_INJECTION
1916 Provide fault-injection capability for alloc_pages().
1918 config FAULT_INJECTION_USERCOPY
1919 bool "Fault injection capability for usercopy functions"
1920 depends on FAULT_INJECTION
1922 Provides fault-injection capability to inject failures
1923 in usercopy functions (copy_from_user(), get_user(), ...).
1925 config FAIL_MAKE_REQUEST
1926 bool "Fault-injection capability for disk IO"
1927 depends on FAULT_INJECTION && BLOCK
1929 Provide fault-injection capability for disk IO.
1931 config FAIL_IO_TIMEOUT
1932 bool "Fault-injection capability for faking disk interrupts"
1933 depends on FAULT_INJECTION && BLOCK
1935 Provide fault-injection capability on end IO handling. This
1936 will make the block layer "forget" an interrupt as configured,
1937 thus exercising the error handling.
1939 Only works with drivers that use the generic timeout handling,
1940 for others it won't do anything.
1943 bool "Fault-injection capability for futexes"
1945 depends on FAULT_INJECTION && FUTEX
1947 Provide fault-injection capability for futexes.
1949 config FAULT_INJECTION_DEBUG_FS
1950 bool "Debugfs entries for fault-injection capabilities"
1951 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1953 Enable configuration of fault-injection capabilities via debugfs.
1955 config FAIL_FUNCTION
1956 bool "Fault-injection capability for functions"
1957 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1959 Provide function-based fault-injection capability.
1960 This will allow you to override a specific function with a return
1961 with given return value. As a result, function caller will see
1962 an error value and have to handle it. This is useful to test the
1963 error handling in various subsystems.
1965 config FAIL_MMC_REQUEST
1966 bool "Fault-injection capability for MMC IO"
1967 depends on FAULT_INJECTION_DEBUG_FS && MMC
1969 Provide fault-injection capability for MMC IO.
1970 This will make the mmc core return data errors. This is
1971 useful to test the error handling in the mmc block device
1972 and to test how the mmc host driver handles retries from
1976 bool "Fault-injection capability for SunRPC"
1977 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1979 Provide fault-injection capability for SunRPC and
1982 config FAULT_INJECTION_STACKTRACE_FILTER
1983 bool "stacktrace filter for fault-injection capabilities"
1984 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1987 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1989 Provide stacktrace filter for fault-injection capabilities
1991 config ARCH_HAS_KCOV
1994 An architecture should select this when it can successfully
1995 build and run with CONFIG_KCOV. This typically requires
1996 disabling instrumentation for some early boot code.
1998 config CC_HAS_SANCOV_TRACE_PC
1999 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2003 bool "Code coverage for fuzzing"
2004 depends on ARCH_HAS_KCOV
2005 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2006 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2007 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
2009 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2010 select OBJTOOL if HAVE_NOINSTR_HACK
2012 KCOV exposes kernel code coverage information in a form suitable
2013 for coverage-guided fuzzing (randomized testing).
2015 If RANDOMIZE_BASE is enabled, PC values will not be stable across
2016 different machines and across reboots. If you need stable PC values,
2017 disable RANDOMIZE_BASE.
2019 For more details, see Documentation/dev-tools/kcov.rst.
2021 config KCOV_ENABLE_COMPARISONS
2022 bool "Enable comparison operands collection by KCOV"
2024 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2026 KCOV also exposes operands of every comparison in the instrumented
2027 code along with operand sizes and PCs of the comparison instructions.
2028 These operands can be used by fuzzing engines to improve the quality
2029 of fuzzing coverage.
2031 config KCOV_INSTRUMENT_ALL
2032 bool "Instrument all code by default"
2036 If you are doing generic system call fuzzing (like e.g. syzkaller),
2037 then you will want to instrument the whole kernel and you should
2038 say y here. If you are doing more targeted fuzzing (like e.g.
2039 filesystem fuzzing with AFL) then you will want to enable coverage
2040 for more specific subsets of files, and should say n here.
2042 config KCOV_IRQ_AREA_SIZE
2043 hex "Size of interrupt coverage collection area in words"
2047 KCOV uses preallocated per-cpu areas to collect coverage from
2048 soft interrupts. This specifies the size of those areas in the
2049 number of unsigned long words.
2051 menuconfig RUNTIME_TESTING_MENU
2052 bool "Runtime Testing"
2055 if RUNTIME_TESTING_MENU
2058 tristate "Linux Kernel Dump Test Tool Module"
2061 This module enables testing of the different dumping mechanisms by
2062 inducing system failures at predefined crash points.
2063 If you don't need it: say N
2064 Choose M here to compile this code as a module. The module will be
2067 Documentation on how to use the module can be found in
2068 Documentation/fault-injection/provoke-crashes.rst
2070 config CPUMASK_KUNIT_TEST
2071 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2073 default KUNIT_ALL_TESTS
2075 Enable to turn on cpumask tests, running at boot or module load time.
2077 For more information on KUnit and unit tests in general, please refer
2078 to the KUnit documentation in Documentation/dev-tools/kunit/.
2082 config TEST_LIST_SORT
2083 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2085 default KUNIT_ALL_TESTS
2087 Enable this to turn on 'list_sort()' function test. This test is
2088 executed only once during system boot (so affects only boot time),
2089 or at module load time.
2093 config TEST_MIN_HEAP
2094 tristate "Min heap test"
2095 depends on DEBUG_KERNEL || m
2097 Enable this to turn on min heap function tests. This test is
2098 executed only once during system boot (so affects only boot time),
2099 or at module load time.
2104 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2106 default KUNIT_ALL_TESTS
2108 This option enables the self-test function of 'sort()' at boot,
2109 or at module load time.
2114 tristate "64bit/32bit division and modulo test"
2115 depends on DEBUG_KERNEL || m
2117 Enable this to turn on 'do_div()' function test. This test is
2118 executed only once during system boot (so affects only boot time),
2119 or at module load time.
2123 config KPROBES_SANITY_TEST
2124 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2125 depends on DEBUG_KERNEL
2128 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2129 default KUNIT_ALL_TESTS
2131 This option provides for testing basic kprobes functionality on
2132 boot. Samples of kprobe and kretprobe are inserted and
2133 verified for functionality.
2135 Say N if you are unsure.
2137 config FPROBE_SANITY_TEST
2138 bool "Self test for fprobe"
2139 depends on DEBUG_KERNEL
2143 This option will enable testing the fprobe when the system boot.
2144 A series of tests are made to verify that the fprobe is functioning
2147 Say N if you are unsure.
2149 config BACKTRACE_SELF_TEST
2150 tristate "Self test for the backtrace code"
2151 depends on DEBUG_KERNEL
2153 This option provides a kernel module that can be used to test
2154 the kernel stack backtrace code. This option is not useful
2155 for distributions or general kernels, but only for kernel
2156 developers working on architecture code.
2158 Note that if you want to also test saved backtraces, you will
2159 have to enable STACKTRACE as well.
2161 Say N if you are unsure.
2163 config TEST_REF_TRACKER
2164 tristate "Self test for reference tracker"
2165 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2168 This option provides a kernel module performing tests
2169 using reference tracker infrastructure.
2171 Say N if you are unsure.
2174 tristate "Red-Black tree test"
2175 depends on DEBUG_KERNEL
2177 A benchmark measuring the performance of the rbtree library.
2178 Also includes rbtree invariant checks.
2180 config REED_SOLOMON_TEST
2181 tristate "Reed-Solomon library test"
2182 depends on DEBUG_KERNEL || m
2184 select REED_SOLOMON_ENC16
2185 select REED_SOLOMON_DEC16
2187 This option enables the self-test function of rslib at boot,
2188 or at module load time.
2192 config INTERVAL_TREE_TEST
2193 tristate "Interval tree test"
2194 depends on DEBUG_KERNEL
2195 select INTERVAL_TREE
2197 A benchmark measuring the performance of the interval tree library
2200 tristate "Per cpu operations test"
2201 depends on m && DEBUG_KERNEL
2203 Enable this option to build test module which validates per-cpu
2208 config ATOMIC64_SELFTEST
2209 tristate "Perform an atomic64_t self-test"
2211 Enable this option to test the atomic64_t functions at boot or
2212 at module load time.
2216 config ASYNC_RAID6_TEST
2217 tristate "Self test for hardware accelerated raid6 recovery"
2218 depends on ASYNC_RAID6_RECOV
2221 This is a one-shot self test that permutes through the
2222 recovery of all the possible two disk failure scenarios for a
2223 N-disk array. Recovery is performed with the asynchronous
2224 raid6 recovery routines, and will optionally use an offload
2225 engine if one is available.
2230 tristate "Test functions located in the hexdump module at runtime"
2232 config STRING_SELFTEST
2233 tristate "Test string functions at runtime"
2235 config TEST_STRING_HELPERS
2236 tristate "Test functions located in the string_helpers module at runtime"
2239 tristate "Test kstrto*() family of functions at runtime"
2242 tristate "Test printf() family of functions at runtime"
2245 tristate "Test scanf() family of functions at runtime"
2248 tristate "Test bitmap_*() family of functions at runtime"
2250 Enable this option to test the bitmap functions at boot.
2255 tristate "Test functions located in the uuid module at runtime"
2258 tristate "Test the XArray code at runtime"
2260 config TEST_MAPLE_TREE
2261 depends on DEBUG_KERNEL
2262 select DEBUG_MAPLE_TREE
2263 tristate "Test the Maple Tree code at runtime"
2265 config TEST_RHASHTABLE
2266 tristate "Perform selftest on resizable hash table"
2268 Enable this option to test the rhashtable functions at boot.
2273 tristate "Perform selftest on IDA functions"
2276 tristate "Perform selftest on priority array manager"
2279 Enable this option to test priority array manager on boot
2284 config TEST_IRQ_TIMINGS
2285 bool "IRQ timings selftest"
2286 depends on IRQ_TIMINGS
2288 Enable this option to test the irq timings code on boot.
2293 tristate "Test module loading with 'hello world' module"
2296 This builds the "test_module" module that emits "Hello, world"
2297 on printk when loaded. It is designed to be used for basic
2298 evaluation of the module loading subsystem (for example when
2299 validating module verification). It lacks any extra dependencies,
2300 and will not normally be loaded by the system unless explicitly
2306 tristate "Test module for compilation of bitops operations"
2309 This builds the "test_bitops" module that is much like the
2310 TEST_LKM module except that it does a basic exercise of the
2311 set/clear_bit macros and get_count_order/long to make sure there are
2312 no compiler warnings from C=1 sparse checker or -Wextra
2313 compilations. It has no dependencies and doesn't run or load unless
2314 explicitly requested by name. for example: modprobe test_bitops.
2319 tristate "Test module for stress/performance analysis of vmalloc allocator"
2324 This builds the "test_vmalloc" module that should be used for
2325 stress and performance analysis. So, any new change for vmalloc
2326 subsystem can be evaluated from performance and stability point
2331 config TEST_USER_COPY
2332 tristate "Test user/kernel boundary protections"
2335 This builds the "test_user_copy" module that runs sanity checks
2336 on the copy_to/from_user infrastructure, making sure basic
2337 user/kernel boundary testing is working. If it fails to load,
2338 a regression has been detected in the user/kernel memory boundary
2344 tristate "Test BPF filter functionality"
2347 This builds the "test_bpf" module that runs various test vectors
2348 against the BPF interpreter or BPF JIT compiler depending on the
2349 current setting. This is in particular useful for BPF JIT compiler
2350 development, but also to run regression tests against changes in
2351 the interpreter code. It also enables test stubs for eBPF maps and
2352 verifier used by user space verifier testsuite.
2356 config TEST_BLACKHOLE_DEV
2357 tristate "Test blackhole netdev functionality"
2360 This builds the "test_blackhole_dev" module that validates the
2361 data path through this blackhole netdev.
2365 config FIND_BIT_BENCHMARK
2366 tristate "Test find_bit functions"
2368 This builds the "test_find_bit" module that measure find_*_bit()
2369 functions performance.
2373 config TEST_FIRMWARE
2374 tristate "Test firmware loading via userspace interface"
2375 depends on FW_LOADER
2377 This builds the "test_firmware" module that creates a userspace
2378 interface for testing firmware loading. This can be used to
2379 control the triggering of firmware loading without needing an
2380 actual firmware-using device. The contents can be rechecked by
2386 tristate "sysctl test driver"
2387 depends on PROC_SYSCTL
2389 This builds the "test_sysctl" module. This driver enables to test the
2390 proc sysctl interfaces available to drivers safely without affecting
2391 production knobs which might alter system functionality.
2395 config BITFIELD_KUNIT
2396 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2398 default KUNIT_ALL_TESTS
2400 Enable this option to test the bitfield functions at boot.
2402 KUnit tests run during boot and output the results to the debug log
2403 in TAP format (http://testanything.org/). Only useful for kernel devs
2404 running the KUnit test harness, and not intended for inclusion into a
2407 For more information on KUnit and unit tests in general please refer
2408 to the KUnit documentation in Documentation/dev-tools/kunit/.
2412 config HASH_KUNIT_TEST
2413 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2415 default KUNIT_ALL_TESTS
2417 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2418 integer (<linux/hash.h>) hash functions on boot.
2420 KUnit tests run during boot and output the results to the debug log
2421 in TAP format (https://testanything.org/). Only useful for kernel devs
2422 running the KUnit test harness, and not intended for inclusion into a
2425 For more information on KUnit and unit tests in general please refer
2426 to the KUnit documentation in Documentation/dev-tools/kunit/.
2428 This is intended to help people writing architecture-specific
2429 optimized versions. If unsure, say N.
2431 config RESOURCE_KUNIT_TEST
2432 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2434 default KUNIT_ALL_TESTS
2436 This builds the resource API unit test.
2437 Tests the logic of API provided by resource.c and ioport.h.
2438 For more information on KUnit and unit tests in general please refer
2439 to the KUnit documentation in Documentation/dev-tools/kunit/.
2443 config SYSCTL_KUNIT_TEST
2444 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2446 default KUNIT_ALL_TESTS
2448 This builds the proc sysctl unit test, which runs on boot.
2449 Tests the API contract and implementation correctness of sysctl.
2450 For more information on KUnit and unit tests in general please refer
2451 to the KUnit documentation in Documentation/dev-tools/kunit/.
2455 config LIST_KUNIT_TEST
2456 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2458 default KUNIT_ALL_TESTS
2460 This builds the linked list KUnit test suite.
2461 It tests that the API and basic functionality of the list_head type
2462 and associated macros.
2464 KUnit tests run during boot and output the results to the debug log
2465 in TAP format (https://testanything.org/). Only useful for kernel devs
2466 running the KUnit test harness, and not intended for inclusion into a
2469 For more information on KUnit and unit tests in general please refer
2470 to the KUnit documentation in Documentation/dev-tools/kunit/.
2474 config LINEAR_RANGES_TEST
2475 tristate "KUnit test for linear_ranges"
2477 select LINEAR_RANGES
2479 This builds the linear_ranges unit test, which runs on boot.
2480 Tests the linear_ranges logic correctness.
2481 For more information on KUnit and unit tests in general please refer
2482 to the KUnit documentation in Documentation/dev-tools/kunit/.
2486 config CMDLINE_KUNIT_TEST
2487 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2489 default KUNIT_ALL_TESTS
2491 This builds the cmdline API unit test.
2492 Tests the logic of API provided by cmdline.c.
2493 For more information on KUnit and unit tests in general please refer
2494 to the KUnit documentation in Documentation/dev-tools/kunit/.
2499 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2501 default KUNIT_ALL_TESTS
2503 This builds the bits unit test.
2504 Tests the logic of macros defined in bits.h.
2505 For more information on KUnit and unit tests in general please refer
2506 to the KUnit documentation in Documentation/dev-tools/kunit/.
2510 config SLUB_KUNIT_TEST
2511 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2512 depends on SLUB_DEBUG && KUNIT
2513 default KUNIT_ALL_TESTS
2515 This builds SLUB allocator unit test.
2516 Tests SLUB cache debugging functionality.
2517 For more information on KUnit and unit tests in general please refer
2518 to the KUnit documentation in Documentation/dev-tools/kunit/.
2522 config RATIONAL_KUNIT_TEST
2523 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2524 depends on KUNIT && RATIONAL
2525 default KUNIT_ALL_TESTS
2527 This builds the rational math unit test.
2528 For more information on KUnit and unit tests in general please refer
2529 to the KUnit documentation in Documentation/dev-tools/kunit/.
2533 config MEMCPY_KUNIT_TEST
2534 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2536 default KUNIT_ALL_TESTS
2538 Builds unit tests for memcpy(), memmove(), and memset() functions.
2539 For more information on KUnit and unit tests in general please refer
2540 to the KUnit documentation in Documentation/dev-tools/kunit/.
2544 config IS_SIGNED_TYPE_KUNIT_TEST
2545 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2547 default KUNIT_ALL_TESTS
2549 Builds unit tests for the is_signed_type() macro.
2551 For more information on KUnit and unit tests in general please refer
2552 to the KUnit documentation in Documentation/dev-tools/kunit/.
2556 config OVERFLOW_KUNIT_TEST
2557 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2559 default KUNIT_ALL_TESTS
2561 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2564 For more information on KUnit and unit tests in general please refer
2565 to the KUnit documentation in Documentation/dev-tools/kunit/.
2569 config STACKINIT_KUNIT_TEST
2570 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2572 default KUNIT_ALL_TESTS
2574 Test if the kernel is zero-initializing stack variables and
2575 padding. Coverage is controlled by compiler flags,
2576 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2577 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2578 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2580 config FORTIFY_KUNIT_TEST
2581 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2582 depends on KUNIT && FORTIFY_SOURCE
2583 default KUNIT_ALL_TESTS
2585 Builds unit tests for checking internals of FORTIFY_SOURCE as used
2586 by the str*() and mem*() family of functions. For testing runtime
2587 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2589 config HW_BREAKPOINT_KUNIT_TEST
2590 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2591 depends on HAVE_HW_BREAKPOINT
2593 default KUNIT_ALL_TESTS
2595 Tests for hw_breakpoint constraints accounting.
2599 config STRSCPY_KUNIT_TEST
2600 tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS
2602 default KUNIT_ALL_TESTS
2604 config SIPHASH_KUNIT_TEST
2605 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2607 default KUNIT_ALL_TESTS
2609 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2610 functions on boot (or module load).
2612 This is intended to help people writing architecture-specific
2613 optimized versions. If unsure, say N.
2616 tristate "udelay test driver"
2618 This builds the "udelay_test" module that helps to make sure
2619 that udelay() is working properly.
2623 config TEST_STATIC_KEYS
2624 tristate "Test static keys"
2627 Test the static key interfaces.
2631 config TEST_DYNAMIC_DEBUG
2632 tristate "Test DYNAMIC_DEBUG"
2633 depends on DYNAMIC_DEBUG
2635 This module registers a tracer callback to count enabled
2636 pr_debugs in a 'do_debugging' function, then alters their
2637 enablements, calls the function, and compares counts.
2642 tristate "kmod stress tester"
2644 depends on NETDEVICES && NET_CORE && INET # for TUN
2646 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2652 Test the kernel's module loading mechanism: kmod. kmod implements
2653 support to load modules using the Linux kernel's usermode helper.
2654 This test provides a series of tests against kmod.
2656 Although technically you can either build test_kmod as a module or
2657 into the kernel we disallow building it into the kernel since
2658 it stress tests request_module() and this will very likely cause
2659 some issues by taking over precious threads available from other
2660 module load requests, ultimately this could be fatal.
2664 tools/testing/selftests/kmod/kmod.sh --help
2668 config TEST_DEBUG_VIRTUAL
2669 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2670 depends on DEBUG_VIRTUAL
2672 Test the kernel's ability to detect incorrect calls to
2673 virt_to_phys() done against the non-linear part of the
2674 kernel's virtual address map.
2678 config TEST_MEMCAT_P
2679 tristate "Test memcat_p() helper function"
2681 Test the memcat_p() helper for correctly merging two
2682 pointer arrays together.
2686 config TEST_LIVEPATCH
2687 tristate "Test livepatching"
2689 depends on DYNAMIC_DEBUG
2690 depends on LIVEPATCH
2693 Test kernel livepatching features for correctness. The tests will
2694 load test modules that will be livepatched in various scenarios.
2696 To run all the livepatching tests:
2698 make -C tools/testing/selftests TARGETS=livepatch run_tests
2700 Alternatively, individual tests may be invoked:
2702 tools/testing/selftests/livepatch/test-callbacks.sh
2703 tools/testing/selftests/livepatch/test-livepatch.sh
2704 tools/testing/selftests/livepatch/test-shadow-vars.sh
2709 tristate "Perform selftest on object aggreration manager"
2713 Enable this option to test object aggregation manager on boot
2717 tristate "Test heap/page initialization"
2719 Test if the kernel is zero-initializing heap and page allocations.
2720 This can be useful to test init_on_alloc and init_on_free features.
2725 tristate "Test HMM (Heterogeneous Memory Management)"
2726 depends on TRANSPARENT_HUGEPAGE
2727 depends on DEVICE_PRIVATE
2731 This is a pseudo device driver solely for testing HMM.
2732 Say M here if you want to build the HMM test module.
2733 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2737 config TEST_FREE_PAGES
2738 tristate "Test freeing pages"
2740 Test that a memory leak does not occur due to a race between
2741 freeing a block of pages and a speculative page reference.
2742 Loading this module is safe if your kernel has the bug fixed.
2743 If the bug is not fixed, it will leak gigabytes of memory and
2744 probably OOM your system.
2747 tristate "Test floating point operations in kernel space"
2748 depends on X86 && !KCOV_INSTRUMENT_ALL
2750 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2751 which will trigger a sequence of floating point operations. This is used
2752 for self-testing floating point control register setting in
2757 config TEST_CLOCKSOURCE_WATCHDOG
2758 tristate "Test clocksource watchdog in kernel space"
2759 depends on CLOCKSOURCE_WATCHDOG
2761 Enable this option to create a kernel module that will trigger
2762 a test of the clocksource watchdog. This module may be loaded
2763 via modprobe or insmod in which case it will run upon being
2764 loaded, or it may be built in, in which case it will run
2769 endif # RUNTIME_TESTING_MENU
2771 config ARCH_USE_MEMTEST
2774 An architecture should select this when it uses early_memtest()
2775 during boot process.
2779 depends on ARCH_USE_MEMTEST
2781 This option adds a kernel parameter 'memtest', which allows memtest
2782 to be set and executed.
2783 memtest=0, mean disabled; -- default
2784 memtest=1, mean do 1 test pattern;
2786 memtest=17, mean do 17 test patterns.
2787 If you are unsure how to answer this question, answer N.
2791 config HYPERV_TESTING
2792 bool "Microsoft Hyper-V driver testing"
2794 depends on HYPERV && DEBUG_FS
2796 Select this option to enable Hyper-V vmbus testing.
2798 endmenu # "Kernel Testing and Coverage"
2802 config RUST_DEBUG_ASSERTIONS
2803 bool "Debug assertions"
2806 Enables rustc's `-Cdebug-assertions` codegen option.
2808 This flag lets you turn `cfg(debug_assertions)` conditional
2809 compilation on or off. This can be used to enable extra debugging
2810 code in development but not in production. For example, it controls
2811 the behavior of the standard library's `debug_assert!` macro.
2813 Note that this will apply to all Rust code, including `core`.
2817 config RUST_OVERFLOW_CHECKS
2818 bool "Overflow checks"
2822 Enables rustc's `-Coverflow-checks` codegen option.
2824 This flag allows you to control the behavior of runtime integer
2825 overflow. When overflow-checks are enabled, a Rust panic will occur
2828 Note that this will apply to all Rust code, including `core`.
2832 config RUST_BUILD_ASSERT_ALLOW
2833 bool "Allow unoptimized build-time assertions"
2836 Controls how are `build_error!` and `build_assert!` handled during build.
2838 If calls to them exist in the binary, it may indicate a violated invariant
2839 or that the optimizer failed to verify the invariant during compilation.
2841 This should not happen, thus by default the build is aborted. However,
2842 as an escape hatch, you can choose Y here to ignore them during build
2843 and let the check be carried at runtime (with `panic!` being called if
2850 source "Documentation/Kconfig"
2852 endmenu # Kernel hacking
projects / linux-2.6-microblaze.git / blob