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.
316 prompt "Compressed Debug information"
318 Compress the resulting debug info. Results in smaller debug info sections,
319 but requires that consumers are able to decompress the results.
321 If unsure, choose DEBUG_INFO_COMPRESSED_NONE.
323 config DEBUG_INFO_COMPRESSED_NONE
324 bool "Don't compress debug information"
326 Don't compress debug info sections.
328 config DEBUG_INFO_COMPRESSED_ZLIB
329 bool "Compress debugging information with zlib"
330 depends on $(cc-option,-gz=zlib)
331 depends on $(ld-option,--compress-debug-sections=zlib)
333 Compress the debug information using zlib. Requires GCC 5.0+ or Clang
334 5.0+, binutils 2.26+, and zlib.
336 Users of dpkg-deb via scripts/package/builddeb may find an increase in
337 size of their debug .deb packages with this config set, due to the
338 debug info being compressed with zlib, then the object files being
339 recompressed with a different compression scheme. But this is still
340 preferable to setting $KDEB_COMPRESS to "none" which would be even
343 config DEBUG_INFO_COMPRESSED_ZSTD
344 bool "Compress debugging information with zstd"
345 depends on $(cc-option,-gz=zstd)
346 depends on $(ld-option,--compress-debug-sections=zstd)
348 Compress the debug information using zstd. This may provide better
349 compression than zlib, for about the same time costs, but requires newer
350 toolchain support. Requires GCC 13.0+ or Clang 16.0+, binutils 2.40+, and
353 endchoice # "Compressed Debug information"
355 config DEBUG_INFO_SPLIT
356 bool "Produce split debuginfo in .dwo files"
357 depends on $(cc-option,-gsplit-dwarf)
359 Generate debug info into separate .dwo files. This significantly
360 reduces the build directory size for builds with DEBUG_INFO,
361 because it stores the information only once on disk in .dwo
362 files instead of multiple times in object files and executables.
363 In addition the debug information is also compressed.
365 Requires recent gcc (4.7+) and recent gdb/binutils.
366 Any tool that packages or reads debug information would need
367 to know about the .dwo files and include them.
368 Incompatible with older versions of ccache.
370 config DEBUG_INFO_BTF
371 bool "Generate BTF typeinfo"
372 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
373 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
374 depends on BPF_SYSCALL
375 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121
377 Generate deduplicated BTF type information from DWARF debug info.
378 Turning this on expects presence of pahole tool, which will convert
379 DWARF type info into equivalent deduplicated BTF type info.
381 config PAHOLE_HAS_SPLIT_BTF
382 def_bool PAHOLE_VERSION >= 119
384 config PAHOLE_HAS_BTF_TAG
385 def_bool PAHOLE_VERSION >= 123
386 depends on CC_IS_CLANG
388 Decide whether pahole emits btf_tag attributes (btf_type_tag and
389 btf_decl_tag) or not. Currently only clang compiler implements
390 these attributes, so make the config depend on CC_IS_CLANG.
392 config PAHOLE_HAS_LANG_EXCLUDE
393 def_bool PAHOLE_VERSION >= 124
395 Support for the --lang_exclude flag which makes pahole exclude
396 compilation units from the supplied language. Used in Kbuild to
397 omit Rust CUs which are not supported in version 1.24 of pahole,
398 otherwise it would emit malformed kernel and module binaries when
399 using DEBUG_INFO_BTF_MODULES.
401 config DEBUG_INFO_BTF_MODULES
403 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
405 Generate compact split BTF type information for kernel modules.
407 config MODULE_ALLOW_BTF_MISMATCH
408 bool "Allow loading modules with non-matching BTF type info"
409 depends on DEBUG_INFO_BTF_MODULES
411 For modules whose split BTF does not match vmlinux, load without
412 BTF rather than refusing to load. The default behavior with
413 module BTF enabled is to reject modules with such mismatches;
414 this option will still load module BTF where possible but ignore
415 it when a mismatch is found.
418 bool "Provide GDB scripts for kernel debugging"
420 This creates the required links to GDB helper scripts in the
421 build directory. If you load vmlinux into gdb, the helper
422 scripts will be automatically imported by gdb as well, and
423 additional functions are available to analyze a Linux kernel
424 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
430 int "Warn for stack frames larger than"
433 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
434 default 2048 if PARISC
435 default 1536 if (!64BIT && XTENSA)
436 default 1280 if KASAN && !64BIT
437 default 1024 if !64BIT
438 default 2048 if 64BIT
440 Tell the compiler to warn at build time for stack frames larger than this.
441 Setting this too low will cause a lot of warnings.
442 Setting it to 0 disables the warning.
444 config STRIP_ASM_SYMS
445 bool "Strip assembler-generated symbols during link"
448 Strip internal assembler-generated symbols during a link (symbols
449 that look like '.Lxxx') so they don't pollute the output of
450 get_wchan() and suchlike.
453 bool "Generate readable assembler code"
454 depends on DEBUG_KERNEL
457 Disable some compiler optimizations that tend to generate human unreadable
458 assembler output. This may make the kernel slightly slower, but it helps
459 to keep kernel developers who have to stare a lot at assembler listings
462 config HEADERS_INSTALL
463 bool "Install uapi headers to usr/include"
466 This option will install uapi headers (headers exported to user-space)
467 into the usr/include directory for use during the kernel build.
468 This is unneeded for building the kernel itself, but needed for some
469 user-space program samples. It is also needed by some features such
470 as uapi header sanity checks.
472 config DEBUG_SECTION_MISMATCH
473 bool "Enable full Section mismatch analysis"
476 The section mismatch analysis checks if there are illegal
477 references from one section to another section.
478 During linktime or runtime, some sections are dropped;
479 any use of code/data previously in these sections would
480 most likely result in an oops.
481 In the code, functions and variables are annotated with
482 __init,, etc. (see the full list in include/linux/init.h),
483 which results in the code/data being placed in specific sections.
484 The section mismatch analysis is always performed after a full
485 kernel build, and enabling this option causes the following
486 additional step to occur:
487 - Add the option -fno-inline-functions-called-once to gcc commands.
488 When inlining a function annotated with __init in a non-init
489 function, we would lose the section information and thus
490 the analysis would not catch the illegal reference.
491 This option tells gcc to inline less (but it does result in
494 config SECTION_MISMATCH_WARN_ONLY
495 bool "Make section mismatch errors non-fatal"
498 If you say N here, the build process will fail if there are any
499 section mismatch, instead of just throwing warnings.
503 config DEBUG_FORCE_FUNCTION_ALIGN_64B
504 bool "Force all function address 64B aligned"
505 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC)
506 select FUNCTION_ALIGNMENT_64B
508 There are cases that a commit from one domain changes the function
509 address alignment of other domains, and cause magic performance
510 bump (regression or improvement). Enable this option will help to
511 verify if the bump is caused by function alignment changes, while
512 it will slightly increase the kernel size and affect icache usage.
514 It is mainly for debug and performance tuning use.
517 # Select this config option from the architecture Kconfig, if it
518 # is preferred to always offer frame pointers as a config
519 # option on the architecture (regardless of KERNEL_DEBUG):
521 config ARCH_WANT_FRAME_POINTERS
525 bool "Compile the kernel with frame pointers"
526 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
527 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
529 If you say Y here the resulting kernel image will be slightly
530 larger and slower, but it gives very useful debugging information
531 in case of kernel bugs. (precise oopses/stacktraces/warnings)
536 config STACK_VALIDATION
537 bool "Compile-time stack metadata validation"
538 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
542 Validate frame pointer rules at compile-time. This helps ensure that
543 runtime stack traces are more reliable.
545 For more information, see
546 tools/objtool/Documentation/objtool.txt.
548 config NOINSTR_VALIDATION
550 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
555 bool "Generate vmlinux.map file when linking"
558 Selecting this option will pass "-Map=vmlinux.map" to ld
559 when linking vmlinux. That file can be useful for verifying
560 and debugging magic section games, and for seeing which
561 pieces of code get eliminated with
562 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
564 config DEBUG_FORCE_WEAK_PER_CPU
565 bool "Force weak per-cpu definitions"
566 depends on DEBUG_KERNEL
568 s390 and alpha require percpu variables in modules to be
569 defined weak to work around addressing range issue which
570 puts the following two restrictions on percpu variable
573 1. percpu symbols must be unique whether static or not
574 2. percpu variables can't be defined inside a function
576 To ensure that generic code follows the above rules, this
577 option forces all percpu variables to be defined as weak.
579 endmenu # "Compiler options"
581 menu "Generic Kernel Debugging Instruments"
584 bool "Magic SysRq key"
587 If you say Y here, you will have some control over the system even
588 if the system crashes for example during kernel debugging (e.g., you
589 will be able to flush the buffer cache to disk, reboot the system
590 immediately or dump some status information). This is accomplished
591 by pressing various keys while holding SysRq (Alt+PrintScreen). It
592 also works on a serial console (on PC hardware at least), if you
593 send a BREAK and then within 5 seconds a command keypress. The
594 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
595 Don't say Y unless you really know what this hack does.
597 config MAGIC_SYSRQ_DEFAULT_ENABLE
598 hex "Enable magic SysRq key functions by default"
599 depends on MAGIC_SYSRQ
602 Specifies which SysRq key functions are enabled by default.
603 This may be set to 1 or 0 to enable or disable them all, or
604 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
606 config MAGIC_SYSRQ_SERIAL
607 bool "Enable magic SysRq key over serial"
608 depends on MAGIC_SYSRQ
611 Many embedded boards have a disconnected TTL level serial which can
612 generate some garbage that can lead to spurious false sysrq detects.
613 This option allows you to decide whether you want to enable the
616 config MAGIC_SYSRQ_SERIAL_SEQUENCE
617 string "Char sequence that enables magic SysRq over serial"
618 depends on MAGIC_SYSRQ_SERIAL
621 Specifies a sequence of characters that can follow BREAK to enable
622 SysRq on a serial console.
624 If unsure, leave an empty string and the option will not be enabled.
627 bool "Debug Filesystem"
629 debugfs is a virtual file system that kernel developers use to put
630 debugging files into. Enable this option to be able to read and
631 write to these files.
633 For detailed documentation on the debugfs API, see
634 Documentation/filesystems/.
639 prompt "Debugfs default access"
641 default DEBUG_FS_ALLOW_ALL
643 This selects the default access restrictions for debugfs.
644 It can be overridden with kernel command line option
645 debugfs=[on,no-mount,off]. The restrictions apply for API access
646 and filesystem registration.
648 config DEBUG_FS_ALLOW_ALL
651 No restrictions apply. Both API and filesystem registration
652 is on. This is the normal default operation.
654 config DEBUG_FS_DISALLOW_MOUNT
655 bool "Do not register debugfs as filesystem"
657 The API is open but filesystem is not loaded. Clients can still do
658 their work and read with debug tools that do not need
661 config DEBUG_FS_ALLOW_NONE
664 Access is off. Clients get -PERM when trying to create nodes in
665 debugfs tree and debugfs is not registered as a filesystem.
666 Client can then back-off or continue without debugfs access.
670 source "lib/Kconfig.kgdb"
671 source "lib/Kconfig.ubsan"
672 source "lib/Kconfig.kcsan"
676 menu "Networking Debugging"
678 source "net/Kconfig.debug"
680 endmenu # "Networking Debugging"
682 menu "Memory Debugging"
684 source "mm/Kconfig.debug"
687 bool "Debug object operations"
688 depends on DEBUG_KERNEL
690 If you say Y here, additional code will be inserted into the
691 kernel to track the life time of various objects and validate
692 the operations on those objects.
694 config DEBUG_OBJECTS_SELFTEST
695 bool "Debug objects selftest"
696 depends on DEBUG_OBJECTS
698 This enables the selftest of the object debug code.
700 config DEBUG_OBJECTS_FREE
701 bool "Debug objects in freed memory"
702 depends on DEBUG_OBJECTS
704 This enables checks whether a k/v free operation frees an area
705 which contains an object which has not been deactivated
706 properly. This can make kmalloc/kfree-intensive workloads
709 config DEBUG_OBJECTS_TIMERS
710 bool "Debug timer objects"
711 depends on DEBUG_OBJECTS
713 If you say Y here, additional code will be inserted into the
714 timer routines to track the life time of timer objects and
715 validate the timer operations.
717 config DEBUG_OBJECTS_WORK
718 bool "Debug work objects"
719 depends on DEBUG_OBJECTS
721 If you say Y here, additional code will be inserted into the
722 work queue routines to track the life time of work objects and
723 validate the work operations.
725 config DEBUG_OBJECTS_RCU_HEAD
726 bool "Debug RCU callbacks objects"
727 depends on DEBUG_OBJECTS
729 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
731 config DEBUG_OBJECTS_PERCPU_COUNTER
732 bool "Debug percpu counter objects"
733 depends on DEBUG_OBJECTS
735 If you say Y here, additional code will be inserted into the
736 percpu counter routines to track the life time of percpu counter
737 objects and validate the percpu counter operations.
739 config DEBUG_OBJECTS_ENABLE_DEFAULT
740 int "debug_objects bootup default value (0-1)"
743 depends on DEBUG_OBJECTS
745 Debug objects boot parameter default value
747 config SHRINKER_DEBUG
748 bool "Enable shrinker debugging support"
751 Say Y to enable the shrinker debugfs interface which provides
752 visibility into the kernel memory shrinkers subsystem.
753 Disable it to avoid an extra memory footprint.
755 config HAVE_DEBUG_KMEMLEAK
758 config DEBUG_KMEMLEAK
759 bool "Kernel memory leak detector"
760 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
762 select STACKTRACE if STACKTRACE_SUPPORT
766 select STACKDEPOT_ALWAYS_INIT if !DEBUG_KMEMLEAK_DEFAULT_OFF
768 Say Y here if you want to enable the memory leak
769 detector. The memory allocation/freeing is traced in a way
770 similar to the Boehm's conservative garbage collector, the
771 difference being that the orphan objects are not freed but
772 only shown in /sys/kernel/debug/kmemleak. Enabling this
773 feature will introduce an overhead to memory
774 allocations. See Documentation/dev-tools/kmemleak.rst for more
777 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
778 of finding leaks due to the slab objects poisoning.
780 In order to access the kmemleak file, debugfs needs to be
781 mounted (usually at /sys/kernel/debug).
783 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
784 int "Kmemleak memory pool size"
785 depends on DEBUG_KMEMLEAK
789 Kmemleak must track all the memory allocations to avoid
790 reporting false positives. Since memory may be allocated or
791 freed before kmemleak is fully initialised, use a static pool
792 of metadata objects to track such callbacks. After kmemleak is
793 fully initialised, this memory pool acts as an emergency one
794 if slab allocations fail.
796 config DEBUG_KMEMLEAK_TEST
797 tristate "Simple test for the kernel memory leak detector"
798 depends on DEBUG_KMEMLEAK && m
800 This option enables a module that explicitly leaks memory.
804 config DEBUG_KMEMLEAK_DEFAULT_OFF
805 bool "Default kmemleak to off"
806 depends on DEBUG_KMEMLEAK
808 Say Y here to disable kmemleak by default. It can then be enabled
809 on the command line via kmemleak=on.
811 config DEBUG_KMEMLEAK_AUTO_SCAN
812 bool "Enable kmemleak auto scan thread on boot up"
814 depends on DEBUG_KMEMLEAK
816 Depending on the cpu, kmemleak scan may be cpu intensive and can
817 stall user tasks at times. This option enables/disables automatic
818 kmemleak scan at boot up.
820 Say N here to disable kmemleak auto scan thread to stop automatic
821 scanning. Disabling this option disables automatic reporting of
826 config DEBUG_STACK_USAGE
827 bool "Stack utilization instrumentation"
828 depends on DEBUG_KERNEL && !IA64
830 Enables the display of the minimum amount of free stack which each
831 task has ever had available in the sysrq-T and sysrq-P debug output.
833 This option will slow down process creation somewhat.
835 config SCHED_STACK_END_CHECK
836 bool "Detect stack corruption on calls to schedule()"
837 depends on DEBUG_KERNEL
840 This option checks for a stack overrun on calls to schedule().
841 If the stack end location is found to be over written always panic as
842 the content of the corrupted region can no longer be trusted.
843 This is to ensure no erroneous behaviour occurs which could result in
844 data corruption or a sporadic crash at a later stage once the region
845 is examined. The runtime overhead introduced is minimal.
847 config ARCH_HAS_DEBUG_VM_PGTABLE
850 An architecture should select this when it can successfully
851 build and run DEBUG_VM_PGTABLE.
853 config DEBUG_VM_IRQSOFF
854 def_bool DEBUG_VM && !PREEMPT_RT
858 depends on DEBUG_KERNEL
860 Enable this to turn on extended checks in the virtual-memory system
861 that may impact performance.
865 config DEBUG_VM_MAPLE_TREE
866 bool "Debug VM maple trees"
868 select DEBUG_MAPLE_TREE
870 Enable VM maple tree debugging information and extra validations.
875 bool "Debug VM red-black trees"
878 Enable VM red-black tree debugging information and extra validations.
882 config DEBUG_VM_PGFLAGS
883 bool "Debug page-flags operations"
886 Enables extra validation on page flags operations.
890 config DEBUG_VM_PGTABLE
891 bool "Debug arch page table for semantics compliance"
893 depends on ARCH_HAS_DEBUG_VM_PGTABLE
894 default y if DEBUG_VM
896 This option provides a debug method which can be used to test
897 architecture page table helper functions on various platforms in
898 verifying if they comply with expected generic MM semantics. This
899 will help architecture code in making sure that any changes or
900 new additions of these helpers still conform to expected
901 semantics of the generic MM. Platforms will have to opt in for
902 this through ARCH_HAS_DEBUG_VM_PGTABLE.
906 config ARCH_HAS_DEBUG_VIRTUAL
910 bool "Debug VM translations"
911 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
913 Enable some costly sanity checks in virtual to page code. This can
914 catch mistakes with virt_to_page() and friends.
918 config DEBUG_NOMMU_REGIONS
919 bool "Debug the global anon/private NOMMU mapping region tree"
920 depends on DEBUG_KERNEL && !MMU
922 This option causes the global tree of anonymous and private mapping
923 regions to be regularly checked for invalid topology.
925 config DEBUG_MEMORY_INIT
926 bool "Debug memory initialisation" if EXPERT
929 Enable this for additional checks during memory initialisation.
930 The sanity checks verify aspects of the VM such as the memory model
931 and other information provided by the architecture. Verbose
932 information will be printed at KERN_DEBUG loglevel depending
933 on the mminit_loglevel= command-line option.
937 config MEMORY_NOTIFIER_ERROR_INJECT
938 tristate "Memory hotplug notifier error injection module"
939 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
941 This option provides the ability to inject artificial errors to
942 memory hotplug notifier chain callbacks. It is controlled through
943 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
945 If the notifier call chain should be failed with some events
946 notified, write the error code to "actions/<notifier event>/error".
948 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
950 # cd /sys/kernel/debug/notifier-error-inject/memory
951 # echo -12 > actions/MEM_GOING_OFFLINE/error
952 # echo offline > /sys/devices/system/memory/memoryXXX/state
953 bash: echo: write error: Cannot allocate memory
955 To compile this code as a module, choose M here: the module will
956 be called memory-notifier-error-inject.
960 config DEBUG_PER_CPU_MAPS
961 bool "Debug access to per_cpu maps"
962 depends on DEBUG_KERNEL
965 Say Y to verify that the per_cpu map being accessed has
966 been set up. This adds a fair amount of code to kernel memory
967 and decreases performance.
971 config DEBUG_KMAP_LOCAL
972 bool "Debug kmap_local temporary mappings"
973 depends on DEBUG_KERNEL && KMAP_LOCAL
975 This option enables additional error checking for the kmap_local
976 infrastructure. Disable for production use.
978 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
981 config DEBUG_KMAP_LOCAL_FORCE_MAP
982 bool "Enforce kmap_local temporary mappings"
983 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
985 select DEBUG_KMAP_LOCAL
987 This option enforces temporary mappings through the kmap_local
988 mechanism for non-highmem pages and on non-highmem systems.
989 Disable this for production systems!
992 bool "Highmem debugging"
993 depends on DEBUG_KERNEL && HIGHMEM
994 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
995 select DEBUG_KMAP_LOCAL
997 This option enables additional error checking for high memory
998 systems. Disable for production systems.
1000 config HAVE_DEBUG_STACKOVERFLOW
1003 config DEBUG_STACKOVERFLOW
1004 bool "Check for stack overflows"
1005 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
1007 Say Y here if you want to check for overflows of kernel, IRQ
1008 and exception stacks (if your architecture uses them). This
1009 option will show detailed messages if free stack space drops
1010 below a certain limit.
1012 These kinds of bugs usually occur when call-chains in the
1013 kernel get too deep, especially when interrupts are
1016 Use this in cases where you see apparently random memory
1017 corruption, especially if it appears in 'struct thread_info'
1019 If in doubt, say "N".
1021 source "lib/Kconfig.kasan"
1022 source "lib/Kconfig.kfence"
1023 source "lib/Kconfig.kmsan"
1025 endmenu # "Memory Debugging"
1028 bool "Debug shared IRQ handlers"
1029 depends on DEBUG_KERNEL
1031 Enable this to generate a spurious interrupt just before a shared
1032 interrupt handler is deregistered (generating one when registering
1033 is currently disabled). Drivers need to handle this correctly. Some
1034 don't and need to be caught.
1036 menu "Debug Oops, Lockups and Hangs"
1038 config PANIC_ON_OOPS
1039 bool "Panic on Oops"
1041 Say Y here to enable the kernel to panic when it oopses. This
1042 has the same effect as setting oops=panic on the kernel command
1045 This feature is useful to ensure that the kernel does not do
1046 anything erroneous after an oops which could result in data
1047 corruption or other issues.
1051 config PANIC_ON_OOPS_VALUE
1054 default 0 if !PANIC_ON_OOPS
1055 default 1 if PANIC_ON_OOPS
1057 config PANIC_TIMEOUT
1061 Set the timeout value (in seconds) until a reboot occurs when
1062 the kernel panics. If n = 0, then we wait forever. A timeout
1063 value n > 0 will wait n seconds before rebooting, while a timeout
1064 value n < 0 will reboot immediately.
1066 config LOCKUP_DETECTOR
1069 config SOFTLOCKUP_DETECTOR
1070 bool "Detect Soft Lockups"
1071 depends on DEBUG_KERNEL && !S390
1072 select LOCKUP_DETECTOR
1074 Say Y here to enable the kernel to act as a watchdog to detect
1077 Softlockups are bugs that cause the kernel to loop in kernel
1078 mode for more than 20 seconds, without giving other tasks a
1079 chance to run. The current stack trace is displayed upon
1080 detection and the system will stay locked up.
1082 config BOOTPARAM_SOFTLOCKUP_PANIC
1083 bool "Panic (Reboot) On Soft Lockups"
1084 depends on SOFTLOCKUP_DETECTOR
1086 Say Y here to enable the kernel to panic on "soft lockups",
1087 which are bugs that cause the kernel to loop in kernel
1088 mode for more than 20 seconds (configurable using the watchdog_thresh
1089 sysctl), without giving other tasks a chance to run.
1091 The panic can be used in combination with panic_timeout,
1092 to cause the system to reboot automatically after a
1093 lockup has been detected. This feature is useful for
1094 high-availability systems that have uptime guarantees and
1095 where a lockup must be resolved ASAP.
1099 config HARDLOCKUP_DETECTOR_PERF
1101 select SOFTLOCKUP_DETECTOR
1104 # Enables a timestamp based low pass filter to compensate for perf based
1105 # hard lockup detection which runs too fast due to turbo modes.
1107 config HARDLOCKUP_CHECK_TIMESTAMP
1111 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1112 # lockup detector rather than the perf based detector.
1114 config HARDLOCKUP_DETECTOR
1115 bool "Detect Hard Lockups"
1116 depends on DEBUG_KERNEL && !S390
1117 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1118 select LOCKUP_DETECTOR
1119 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1121 Say Y here to enable the kernel to act as a watchdog to detect
1124 Hardlockups are bugs that cause the CPU to loop in kernel mode
1125 for more than 10 seconds, without letting other interrupts have a
1126 chance to run. The current stack trace is displayed upon detection
1127 and the system will stay locked up.
1129 config BOOTPARAM_HARDLOCKUP_PANIC
1130 bool "Panic (Reboot) On Hard Lockups"
1131 depends on HARDLOCKUP_DETECTOR
1133 Say Y here to enable the kernel to panic on "hard lockups",
1134 which are bugs that cause the kernel to loop in kernel
1135 mode with interrupts disabled for more than 10 seconds (configurable
1136 using the watchdog_thresh sysctl).
1140 config DETECT_HUNG_TASK
1141 bool "Detect Hung Tasks"
1142 depends on DEBUG_KERNEL
1143 default SOFTLOCKUP_DETECTOR
1145 Say Y here to enable the kernel to detect "hung tasks",
1146 which are bugs that cause the task to be stuck in
1147 uninterruptible "D" state indefinitely.
1149 When a hung task is detected, the kernel will print the
1150 current stack trace (which you should report), but the
1151 task will stay in uninterruptible state. If lockdep is
1152 enabled then all held locks will also be reported. This
1153 feature has negligible overhead.
1155 config DEFAULT_HUNG_TASK_TIMEOUT
1156 int "Default timeout for hung task detection (in seconds)"
1157 depends on DETECT_HUNG_TASK
1160 This option controls the default timeout (in seconds) used
1161 to determine when a task has become non-responsive and should
1164 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1165 sysctl or by writing a value to
1166 /proc/sys/kernel/hung_task_timeout_secs.
1168 A timeout of 0 disables the check. The default is two minutes.
1169 Keeping the default should be fine in most cases.
1171 config BOOTPARAM_HUNG_TASK_PANIC
1172 bool "Panic (Reboot) On Hung Tasks"
1173 depends on DETECT_HUNG_TASK
1175 Say Y here to enable the kernel to panic on "hung tasks",
1176 which are bugs that cause the kernel to leave a task stuck
1177 in uninterruptible "D" state.
1179 The panic can be used in combination with panic_timeout,
1180 to cause the system to reboot automatically after a
1181 hung task has been detected. This feature is useful for
1182 high-availability systems that have uptime guarantees and
1183 where a hung tasks must be resolved ASAP.
1188 bool "Detect Workqueue Stalls"
1189 depends on DEBUG_KERNEL
1191 Say Y here to enable stall detection on workqueues. If a
1192 worker pool doesn't make forward progress on a pending work
1193 item for over a given amount of time, 30s by default, a
1194 warning message is printed along with dump of workqueue
1195 state. This can be configured through kernel parameter
1196 "workqueue.watchdog_thresh" and its sysfs counterpart.
1199 tristate "Test module to generate lockups"
1202 This builds the "test_lockup" module that helps to make sure
1203 that watchdogs and lockup detectors are working properly.
1205 Depending on module parameters it could emulate soft or hard
1206 lockup, "hung task", or locking arbitrary lock for a long time.
1207 Also it could generate series of lockups with cooling-down periods.
1211 endmenu # "Debug lockups and hangs"
1213 menu "Scheduler Debugging"
1216 bool "Collect scheduler debugging info"
1217 depends on DEBUG_KERNEL && PROC_FS
1220 If you say Y here, the /sys/kernel/debug/sched file will be provided
1221 that can help debug the scheduler. The runtime overhead of this
1229 bool "Collect scheduler statistics"
1230 depends on DEBUG_KERNEL && PROC_FS
1233 If you say Y here, additional code will be inserted into the
1234 scheduler and related routines to collect statistics about
1235 scheduler behavior and provide them in /proc/schedstat. These
1236 stats may be useful for both tuning and debugging the scheduler
1237 If you aren't debugging the scheduler or trying to tune a specific
1238 application, you can say N to avoid the very slight overhead
1243 config DEBUG_TIMEKEEPING
1244 bool "Enable extra timekeeping sanity checking"
1246 This option will enable additional timekeeping sanity checks
1247 which may be helpful when diagnosing issues where timekeeping
1248 problems are suspected.
1250 This may include checks in the timekeeping hotpaths, so this
1251 option may have a (very small) performance impact to some
1256 config DEBUG_PREEMPT
1257 bool "Debug preemptible kernel"
1258 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1261 If you say Y here then the kernel will use a debug variant of the
1262 commonly used smp_processor_id() function and will print warnings
1263 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1264 will detect preemption count underflows.
1266 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1268 config LOCK_DEBUGGING_SUPPORT
1270 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1273 config PROVE_LOCKING
1274 bool "Lock debugging: prove locking correctness"
1275 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1277 select DEBUG_SPINLOCK
1278 select DEBUG_MUTEXES if !PREEMPT_RT
1279 select DEBUG_RT_MUTEXES if RT_MUTEXES
1281 select DEBUG_WW_MUTEX_SLOWPATH
1282 select DEBUG_LOCK_ALLOC
1283 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1284 select TRACE_IRQFLAGS
1287 This feature enables the kernel to prove that all locking
1288 that occurs in the kernel runtime is mathematically
1289 correct: that under no circumstance could an arbitrary (and
1290 not yet triggered) combination of observed locking
1291 sequences (on an arbitrary number of CPUs, running an
1292 arbitrary number of tasks and interrupt contexts) cause a
1295 In short, this feature enables the kernel to report locking
1296 related deadlocks before they actually occur.
1298 The proof does not depend on how hard and complex a
1299 deadlock scenario would be to trigger: how many
1300 participant CPUs, tasks and irq-contexts would be needed
1301 for it to trigger. The proof also does not depend on
1302 timing: if a race and a resulting deadlock is possible
1303 theoretically (no matter how unlikely the race scenario
1304 is), it will be proven so and will immediately be
1305 reported by the kernel (once the event is observed that
1306 makes the deadlock theoretically possible).
1308 If a deadlock is impossible (i.e. the locking rules, as
1309 observed by the kernel, are mathematically correct), the
1310 kernel reports nothing.
1312 NOTE: this feature can also be enabled for rwlocks, mutexes
1313 and rwsems - in which case all dependencies between these
1314 different locking variants are observed and mapped too, and
1315 the proof of observed correctness is also maintained for an
1316 arbitrary combination of these separate locking variants.
1318 For more details, see Documentation/locking/lockdep-design.rst.
1320 config PROVE_RAW_LOCK_NESTING
1321 bool "Enable raw_spinlock - spinlock nesting checks"
1322 depends on PROVE_LOCKING
1325 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1326 that the lock nesting rules for PREEMPT_RT enabled kernels are
1329 NOTE: There are known nesting problems. So if you enable this
1330 option expect lockdep splats until these problems have been fully
1331 addressed which is work in progress. This config switch allows to
1332 identify and analyze these problems. It will be removed and the
1333 check permanently enabled once the main issues have been fixed.
1335 If unsure, select N.
1338 bool "Lock usage statistics"
1339 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1341 select DEBUG_SPINLOCK
1342 select DEBUG_MUTEXES if !PREEMPT_RT
1343 select DEBUG_RT_MUTEXES if RT_MUTEXES
1344 select DEBUG_LOCK_ALLOC
1347 This feature enables tracking lock contention points
1349 For more details, see Documentation/locking/lockstat.rst
1351 This also enables lock events required by "perf lock",
1353 If you want to use "perf lock", you also need to turn on
1354 CONFIG_EVENT_TRACING.
1356 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1357 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1359 config DEBUG_RT_MUTEXES
1360 bool "RT Mutex debugging, deadlock detection"
1361 depends on DEBUG_KERNEL && RT_MUTEXES
1363 This allows rt mutex semantics violations and rt mutex related
1364 deadlocks (lockups) to be detected and reported automatically.
1366 config DEBUG_SPINLOCK
1367 bool "Spinlock and rw-lock debugging: basic checks"
1368 depends on DEBUG_KERNEL
1369 select UNINLINE_SPIN_UNLOCK
1371 Say Y here and build SMP to catch missing spinlock initialization
1372 and certain other kinds of spinlock errors commonly made. This is
1373 best used in conjunction with the NMI watchdog so that spinlock
1374 deadlocks are also debuggable.
1376 config DEBUG_MUTEXES
1377 bool "Mutex debugging: basic checks"
1378 depends on DEBUG_KERNEL && !PREEMPT_RT
1380 This feature allows mutex semantics violations to be detected and
1383 config DEBUG_WW_MUTEX_SLOWPATH
1384 bool "Wait/wound mutex debugging: Slowpath testing"
1385 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1386 select DEBUG_LOCK_ALLOC
1387 select DEBUG_SPINLOCK
1388 select DEBUG_MUTEXES if !PREEMPT_RT
1389 select DEBUG_RT_MUTEXES if PREEMPT_RT
1391 This feature enables slowpath testing for w/w mutex users by
1392 injecting additional -EDEADLK wound/backoff cases. Together with
1393 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1394 will test all possible w/w mutex interface abuse with the
1395 exception of simply not acquiring all the required locks.
1396 Note that this feature can introduce significant overhead, so
1397 it really should not be enabled in a production or distro kernel,
1398 even a debug kernel. If you are a driver writer, enable it. If
1399 you are a distro, do not.
1402 bool "RW Semaphore debugging: basic checks"
1403 depends on DEBUG_KERNEL
1405 This debugging feature allows mismatched rw semaphore locks
1406 and unlocks to be detected and reported.
1408 config DEBUG_LOCK_ALLOC
1409 bool "Lock debugging: detect incorrect freeing of live locks"
1410 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1411 select DEBUG_SPINLOCK
1412 select DEBUG_MUTEXES if !PREEMPT_RT
1413 select DEBUG_RT_MUTEXES if RT_MUTEXES
1416 This feature will check whether any held lock (spinlock, rwlock,
1417 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1418 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1419 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1420 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1421 held during task exit.
1425 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1430 config LOCKDEP_SMALL
1434 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1435 depends on LOCKDEP && !LOCKDEP_SMALL
1439 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1441 config LOCKDEP_CHAINS_BITS
1442 int "Bitsize for MAX_LOCKDEP_CHAINS"
1443 depends on LOCKDEP && !LOCKDEP_SMALL
1447 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1449 config LOCKDEP_STACK_TRACE_BITS
1450 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1451 depends on LOCKDEP && !LOCKDEP_SMALL
1455 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1457 config LOCKDEP_STACK_TRACE_HASH_BITS
1458 int "Bitsize for STACK_TRACE_HASH_SIZE"
1459 depends on LOCKDEP && !LOCKDEP_SMALL
1463 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1465 config LOCKDEP_CIRCULAR_QUEUE_BITS
1466 int "Bitsize for elements in circular_queue struct"
1471 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1473 config DEBUG_LOCKDEP
1474 bool "Lock dependency engine debugging"
1475 depends on DEBUG_KERNEL && LOCKDEP
1476 select DEBUG_IRQFLAGS
1478 If you say Y here, the lock dependency engine will do
1479 additional runtime checks to debug itself, at the price
1480 of more runtime overhead.
1482 config DEBUG_ATOMIC_SLEEP
1483 bool "Sleep inside atomic section checking"
1484 select PREEMPT_COUNT
1485 depends on DEBUG_KERNEL
1486 depends on !ARCH_NO_PREEMPT
1488 If you say Y here, various routines which may sleep will become very
1489 noisy if they are called inside atomic sections: when a spinlock is
1490 held, inside an rcu read side critical section, inside preempt disabled
1491 sections, inside an interrupt, etc...
1493 config DEBUG_LOCKING_API_SELFTESTS
1494 bool "Locking API boot-time self-tests"
1495 depends on DEBUG_KERNEL
1497 Say Y here if you want the kernel to run a short self-test during
1498 bootup. The self-test checks whether common types of locking bugs
1499 are detected by debugging mechanisms or not. (if you disable
1500 lock debugging then those bugs won't be detected of course.)
1501 The following locking APIs are covered: spinlocks, rwlocks,
1504 config LOCK_TORTURE_TEST
1505 tristate "torture tests for locking"
1506 depends on DEBUG_KERNEL
1509 This option provides a kernel module that runs torture tests
1510 on kernel locking primitives. The kernel module may be built
1511 after the fact on the running kernel to be tested, if desired.
1513 Say Y here if you want kernel locking-primitive torture tests
1514 to be built into the kernel.
1515 Say M if you want these torture tests to build as a module.
1516 Say N if you are unsure.
1518 config WW_MUTEX_SELFTEST
1519 tristate "Wait/wound mutex selftests"
1521 This option provides a kernel module that runs tests on the
1522 on the struct ww_mutex locking API.
1524 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1525 with this test harness.
1527 Say M if you want these self tests to build as a module.
1528 Say N if you are unsure.
1530 config SCF_TORTURE_TEST
1531 tristate "torture tests for smp_call_function*()"
1532 depends on DEBUG_KERNEL
1535 This option provides a kernel module that runs torture tests
1536 on the smp_call_function() family of primitives. The kernel
1537 module may be built after the fact on the running kernel to
1538 be tested, if desired.
1540 config CSD_LOCK_WAIT_DEBUG
1541 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1542 depends on DEBUG_KERNEL
1546 This option enables debug prints when CPUs are slow to respond
1547 to the smp_call_function*() IPI wrappers. These debug prints
1548 include the IPI handler function currently executing (if any)
1549 and relevant stack traces.
1551 endmenu # lock debugging
1553 config TRACE_IRQFLAGS
1554 depends on TRACE_IRQFLAGS_SUPPORT
1557 Enables hooks to interrupt enabling and disabling for
1558 either tracing or lock debugging.
1560 config TRACE_IRQFLAGS_NMI
1562 depends on TRACE_IRQFLAGS
1563 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1565 config NMI_CHECK_CPU
1566 bool "Debugging for CPUs failing to respond to backtrace requests"
1567 depends on DEBUG_KERNEL
1571 Enables debug prints when a CPU fails to respond to a given
1572 backtrace NMI. These prints provide some reasons why a CPU
1573 might legitimately be failing to respond, for example, if it
1574 is offline of if ignore_nmis is set.
1576 config DEBUG_IRQFLAGS
1577 bool "Debug IRQ flag manipulation"
1579 Enables checks for potentially unsafe enabling or disabling of
1580 interrupts, such as calling raw_local_irq_restore() when interrupts
1584 bool "Stack backtrace support"
1585 depends on STACKTRACE_SUPPORT
1587 This option causes the kernel to create a /proc/pid/stack for
1588 every process, showing its current stack trace.
1589 It is also used by various kernel debugging features that require
1590 stack trace generation.
1592 config WARN_ALL_UNSEEDED_RANDOM
1593 bool "Warn for all uses of unseeded randomness"
1596 Some parts of the kernel contain bugs relating to their use of
1597 cryptographically secure random numbers before it's actually possible
1598 to generate those numbers securely. This setting ensures that these
1599 flaws don't go unnoticed, by enabling a message, should this ever
1600 occur. This will allow people with obscure setups to know when things
1601 are going wrong, so that they might contact developers about fixing
1604 Unfortunately, on some models of some architectures getting
1605 a fully seeded CRNG is extremely difficult, and so this can
1606 result in dmesg getting spammed for a surprisingly long
1607 time. This is really bad from a security perspective, and
1608 so architecture maintainers really need to do what they can
1609 to get the CRNG seeded sooner after the system is booted.
1610 However, since users cannot do anything actionable to
1611 address this, by default this option is disabled.
1613 Say Y here if you want to receive warnings for all uses of
1614 unseeded randomness. This will be of use primarily for
1615 those developers interested in improving the security of
1616 Linux kernels running on their architecture (or
1619 config DEBUG_KOBJECT
1620 bool "kobject debugging"
1621 depends on DEBUG_KERNEL
1623 If you say Y here, some extra kobject debugging messages will be sent
1626 config DEBUG_KOBJECT_RELEASE
1627 bool "kobject release debugging"
1628 depends on DEBUG_OBJECTS_TIMERS
1630 kobjects are reference counted objects. This means that their
1631 last reference count put is not predictable, and the kobject can
1632 live on past the point at which a driver decides to drop its
1633 initial reference to the kobject gained on allocation. An
1634 example of this would be a struct device which has just been
1637 However, some buggy drivers assume that after such an operation,
1638 the memory backing the kobject can be immediately freed. This
1639 goes completely against the principles of a refcounted object.
1641 If you say Y here, the kernel will delay the release of kobjects
1642 on the last reference count to improve the visibility of this
1643 kind of kobject release bug.
1645 config HAVE_DEBUG_BUGVERBOSE
1648 menu "Debug kernel data structures"
1651 bool "Debug linked list manipulation"
1652 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1654 Enable this to turn on extended checks in the linked-list
1660 bool "Debug priority linked list manipulation"
1661 depends on DEBUG_KERNEL
1663 Enable this to turn on extended checks in the priority-ordered
1664 linked-list (plist) walking routines. This checks the entire
1665 list multiple times during each manipulation.
1670 bool "Debug SG table operations"
1671 depends on DEBUG_KERNEL
1673 Enable this to turn on checks on scatter-gather tables. This can
1674 help find problems with drivers that do not properly initialize
1679 config DEBUG_NOTIFIERS
1680 bool "Debug notifier call chains"
1681 depends on DEBUG_KERNEL
1683 Enable this to turn on sanity checking for notifier call chains.
1684 This is most useful for kernel developers to make sure that
1685 modules properly unregister themselves from notifier chains.
1686 This is a relatively cheap check but if you care about maximum
1689 config BUG_ON_DATA_CORRUPTION
1690 bool "Trigger a BUG when data corruption is detected"
1693 Select this option if the kernel should BUG when it encounters
1694 data corruption in kernel memory structures when they get checked
1699 config DEBUG_MAPLE_TREE
1700 bool "Debug maple trees"
1701 depends on DEBUG_KERNEL
1703 Enable maple tree debugging information and extra validations.
1709 config DEBUG_CREDENTIALS
1710 bool "Debug credential management"
1711 depends on DEBUG_KERNEL
1713 Enable this to turn on some debug checking for credential
1714 management. The additional code keeps track of the number of
1715 pointers from task_structs to any given cred struct, and checks to
1716 see that this number never exceeds the usage count of the cred
1719 Furthermore, if SELinux is enabled, this also checks that the
1720 security pointer in the cred struct is never seen to be invalid.
1724 source "kernel/rcu/Kconfig.debug"
1726 config DEBUG_WQ_FORCE_RR_CPU
1727 bool "Force round-robin CPU selection for unbound work items"
1728 depends on DEBUG_KERNEL
1731 Workqueue used to implicitly guarantee that work items queued
1732 without explicit CPU specified are put on the local CPU. This
1733 guarantee is no longer true and while local CPU is still
1734 preferred work items may be put on foreign CPUs. Kernel
1735 parameter "workqueue.debug_force_rr_cpu" is added to force
1736 round-robin CPU selection to flush out usages which depend on the
1737 now broken guarantee. This config option enables the debug
1738 feature by default. When enabled, memory and cache locality will
1741 config CPU_HOTPLUG_STATE_CONTROL
1742 bool "Enable CPU hotplug state control"
1743 depends on DEBUG_KERNEL
1744 depends on HOTPLUG_CPU
1747 Allows to write steps between "offline" and "online" to the CPUs
1748 sysfs target file so states can be stepped granular. This is a debug
1749 option for now as the hotplug machinery cannot be stopped and
1750 restarted at arbitrary points yet.
1752 Say N if your are unsure.
1755 bool "Latency measuring infrastructure"
1756 depends on DEBUG_KERNEL
1757 depends on STACKTRACE_SUPPORT
1759 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1765 Enable this option if you want to use the LatencyTOP tool
1766 to find out which userspace is blocking on what kernel operations.
1768 config DEBUG_CGROUP_REF
1769 bool "Disable inlining of cgroup css reference count functions"
1770 depends on DEBUG_KERNEL
1775 Force cgroup css reference count functions to not be inlined so
1776 that they can be kprobed for debugging.
1778 source "kernel/trace/Kconfig"
1780 config PROVIDE_OHCI1394_DMA_INIT
1781 bool "Remote debugging over FireWire early on boot"
1782 depends on PCI && X86
1784 If you want to debug problems which hang or crash the kernel early
1785 on boot and the crashing machine has a FireWire port, you can use
1786 this feature to remotely access the memory of the crashed machine
1787 over FireWire. This employs remote DMA as part of the OHCI1394
1788 specification which is now the standard for FireWire controllers.
1790 With remote DMA, you can monitor the printk buffer remotely using
1791 firescope and access all memory below 4GB using fireproxy from gdb.
1792 Even controlling a kernel debugger is possible using remote DMA.
1796 If ohci1394_dma=early is used as boot parameter, it will initialize
1797 all OHCI1394 controllers which are found in the PCI config space.
1799 As all changes to the FireWire bus such as enabling and disabling
1800 devices cause a bus reset and thereby disable remote DMA for all
1801 devices, be sure to have the cable plugged and FireWire enabled on
1802 the debugging host before booting the debug target for debugging.
1804 This code (~1k) is freed after boot. By then, the firewire stack
1805 in charge of the OHCI-1394 controllers should be used instead.
1807 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1809 source "samples/Kconfig"
1811 config ARCH_HAS_DEVMEM_IS_ALLOWED
1814 config STRICT_DEVMEM
1815 bool "Filter access to /dev/mem"
1816 depends on MMU && DEVMEM
1817 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1818 default y if PPC || X86 || ARM64
1820 If this option is disabled, you allow userspace (root) access to all
1821 of memory, including kernel and userspace memory. Accidental
1822 access to this is obviously disastrous, but specific access can
1823 be used by people debugging the kernel. Note that with PAT support
1824 enabled, even in this case there are restrictions on /dev/mem
1825 use due to the cache aliasing requirements.
1827 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1828 file only allows userspace access to PCI space and the BIOS code and
1829 data regions. This is sufficient for dosemu and X and all common
1834 config IO_STRICT_DEVMEM
1835 bool "Filter I/O access to /dev/mem"
1836 depends on STRICT_DEVMEM
1838 If this option is disabled, you allow userspace (root) access to all
1839 io-memory regardless of whether a driver is actively using that
1840 range. Accidental access to this is obviously disastrous, but
1841 specific access can be used by people debugging kernel drivers.
1843 If this option is switched on, the /dev/mem file only allows
1844 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1845 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1846 if the driver using a given range cannot be disabled.
1850 menu "$(SRCARCH) Debugging"
1852 source "arch/$(SRCARCH)/Kconfig.debug"
1856 menu "Kernel Testing and Coverage"
1858 source "lib/kunit/Kconfig"
1860 config NOTIFIER_ERROR_INJECTION
1861 tristate "Notifier error injection"
1862 depends on DEBUG_KERNEL
1865 This option provides the ability to inject artificial errors to
1866 specified notifier chain callbacks. It is useful to test the error
1867 handling of notifier call chain failures.
1871 config PM_NOTIFIER_ERROR_INJECT
1872 tristate "PM notifier error injection module"
1873 depends on PM && NOTIFIER_ERROR_INJECTION
1874 default m if PM_DEBUG
1876 This option provides the ability to inject artificial errors to
1877 PM notifier chain callbacks. It is controlled through debugfs
1878 interface /sys/kernel/debug/notifier-error-inject/pm
1880 If the notifier call chain should be failed with some events
1881 notified, write the error code to "actions/<notifier event>/error".
1883 Example: Inject PM suspend error (-12 = -ENOMEM)
1885 # cd /sys/kernel/debug/notifier-error-inject/pm/
1886 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1887 # echo mem > /sys/power/state
1888 bash: echo: write error: Cannot allocate memory
1890 To compile this code as a module, choose M here: the module will
1891 be called pm-notifier-error-inject.
1895 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1896 tristate "OF reconfig notifier error injection module"
1897 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1899 This option provides the ability to inject artificial errors to
1900 OF reconfig notifier chain callbacks. It is controlled
1901 through debugfs interface under
1902 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1904 If the notifier call chain should be failed with some events
1905 notified, write the error code to "actions/<notifier event>/error".
1907 To compile this code as a module, choose M here: the module will
1908 be called of-reconfig-notifier-error-inject.
1912 config NETDEV_NOTIFIER_ERROR_INJECT
1913 tristate "Netdev notifier error injection module"
1914 depends on NET && NOTIFIER_ERROR_INJECTION
1916 This option provides the ability to inject artificial errors to
1917 netdevice notifier chain callbacks. It is controlled through debugfs
1918 interface /sys/kernel/debug/notifier-error-inject/netdev
1920 If the notifier call chain should be failed with some events
1921 notified, write the error code to "actions/<notifier event>/error".
1923 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1925 # cd /sys/kernel/debug/notifier-error-inject/netdev
1926 # echo -22 > actions/NETDEV_CHANGEMTU/error
1927 # ip link set eth0 mtu 1024
1928 RTNETLINK answers: Invalid argument
1930 To compile this code as a module, choose M here: the module will
1931 be called netdev-notifier-error-inject.
1935 config FUNCTION_ERROR_INJECTION
1936 bool "Fault-injections of functions"
1937 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1939 Add fault injections into various functions that are annotated with
1940 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
1941 value of these functions. This is useful to test error paths of code.
1945 config FAULT_INJECTION
1946 bool "Fault-injection framework"
1947 depends on DEBUG_KERNEL
1949 Provide fault-injection framework.
1950 For more details, see Documentation/fault-injection/.
1953 bool "Fault-injection capability for kmalloc"
1954 depends on FAULT_INJECTION
1955 depends on SLAB || SLUB
1957 Provide fault-injection capability for kmalloc.
1959 config FAIL_PAGE_ALLOC
1960 bool "Fault-injection capability for alloc_pages()"
1961 depends on FAULT_INJECTION
1963 Provide fault-injection capability for alloc_pages().
1965 config FAULT_INJECTION_USERCOPY
1966 bool "Fault injection capability for usercopy functions"
1967 depends on FAULT_INJECTION
1969 Provides fault-injection capability to inject failures
1970 in usercopy functions (copy_from_user(), get_user(), ...).
1972 config FAIL_MAKE_REQUEST
1973 bool "Fault-injection capability for disk IO"
1974 depends on FAULT_INJECTION && BLOCK
1976 Provide fault-injection capability for disk IO.
1978 config FAIL_IO_TIMEOUT
1979 bool "Fault-injection capability for faking disk interrupts"
1980 depends on FAULT_INJECTION && BLOCK
1982 Provide fault-injection capability on end IO handling. This
1983 will make the block layer "forget" an interrupt as configured,
1984 thus exercising the error handling.
1986 Only works with drivers that use the generic timeout handling,
1987 for others it won't do anything.
1990 bool "Fault-injection capability for futexes"
1992 depends on FAULT_INJECTION && FUTEX
1994 Provide fault-injection capability for futexes.
1996 config FAULT_INJECTION_DEBUG_FS
1997 bool "Debugfs entries for fault-injection capabilities"
1998 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
2000 Enable configuration of fault-injection capabilities via debugfs.
2002 config FAIL_FUNCTION
2003 bool "Fault-injection capability for functions"
2004 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
2006 Provide function-based fault-injection capability.
2007 This will allow you to override a specific function with a return
2008 with given return value. As a result, function caller will see
2009 an error value and have to handle it. This is useful to test the
2010 error handling in various subsystems.
2012 config FAIL_MMC_REQUEST
2013 bool "Fault-injection capability for MMC IO"
2014 depends on FAULT_INJECTION_DEBUG_FS && MMC
2016 Provide fault-injection capability for MMC IO.
2017 This will make the mmc core return data errors. This is
2018 useful to test the error handling in the mmc block device
2019 and to test how the mmc host driver handles retries from
2023 bool "Fault-injection capability for SunRPC"
2024 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2026 Provide fault-injection capability for SunRPC and
2029 config FAULT_INJECTION_STACKTRACE_FILTER
2030 bool "stacktrace filter for fault-injection capabilities"
2031 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
2033 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2035 Provide stacktrace filter for fault-injection capabilities
2037 config ARCH_HAS_KCOV
2040 An architecture should select this when it can successfully
2041 build and run with CONFIG_KCOV. This typically requires
2042 disabling instrumentation for some early boot code.
2044 config CC_HAS_SANCOV_TRACE_PC
2045 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2049 bool "Code coverage for fuzzing"
2050 depends on ARCH_HAS_KCOV
2051 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2052 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2053 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
2055 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2056 select OBJTOOL if HAVE_NOINSTR_HACK
2058 KCOV exposes kernel code coverage information in a form suitable
2059 for coverage-guided fuzzing (randomized testing).
2061 If RANDOMIZE_BASE is enabled, PC values will not be stable across
2062 different machines and across reboots. If you need stable PC values,
2063 disable RANDOMIZE_BASE.
2065 For more details, see Documentation/dev-tools/kcov.rst.
2067 config KCOV_ENABLE_COMPARISONS
2068 bool "Enable comparison operands collection by KCOV"
2070 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2072 KCOV also exposes operands of every comparison in the instrumented
2073 code along with operand sizes and PCs of the comparison instructions.
2074 These operands can be used by fuzzing engines to improve the quality
2075 of fuzzing coverage.
2077 config KCOV_INSTRUMENT_ALL
2078 bool "Instrument all code by default"
2082 If you are doing generic system call fuzzing (like e.g. syzkaller),
2083 then you will want to instrument the whole kernel and you should
2084 say y here. If you are doing more targeted fuzzing (like e.g.
2085 filesystem fuzzing with AFL) then you will want to enable coverage
2086 for more specific subsets of files, and should say n here.
2088 config KCOV_IRQ_AREA_SIZE
2089 hex "Size of interrupt coverage collection area in words"
2093 KCOV uses preallocated per-cpu areas to collect coverage from
2094 soft interrupts. This specifies the size of those areas in the
2095 number of unsigned long words.
2097 menuconfig RUNTIME_TESTING_MENU
2098 bool "Runtime Testing"
2101 if RUNTIME_TESTING_MENU
2104 tristate "Linux Kernel Dump Test Tool Module"
2107 This module enables testing of the different dumping mechanisms by
2108 inducing system failures at predefined crash points.
2109 If you don't need it: say N
2110 Choose M here to compile this code as a module. The module will be
2113 Documentation on how to use the module can be found in
2114 Documentation/fault-injection/provoke-crashes.rst
2116 config CPUMASK_KUNIT_TEST
2117 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2119 default KUNIT_ALL_TESTS
2121 Enable to turn on cpumask tests, running at boot or module load time.
2123 For more information on KUnit and unit tests in general, please refer
2124 to the KUnit documentation in Documentation/dev-tools/kunit/.
2128 config TEST_LIST_SORT
2129 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2131 default KUNIT_ALL_TESTS
2133 Enable this to turn on 'list_sort()' function test. This test is
2134 executed only once during system boot (so affects only boot time),
2135 or at module load time.
2139 config TEST_MIN_HEAP
2140 tristate "Min heap test"
2141 depends on DEBUG_KERNEL || m
2143 Enable this to turn on min heap function tests. This test is
2144 executed only once during system boot (so affects only boot time),
2145 or at module load time.
2150 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2152 default KUNIT_ALL_TESTS
2154 This option enables the self-test function of 'sort()' at boot,
2155 or at module load time.
2160 tristate "64bit/32bit division and modulo test"
2161 depends on DEBUG_KERNEL || m
2163 Enable this to turn on 'do_div()' function test. This test is
2164 executed only once during system boot (so affects only boot time),
2165 or at module load time.
2169 config KPROBES_SANITY_TEST
2170 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2171 depends on DEBUG_KERNEL
2174 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2175 default KUNIT_ALL_TESTS
2177 This option provides for testing basic kprobes functionality on
2178 boot. Samples of kprobe and kretprobe are inserted and
2179 verified for functionality.
2181 Say N if you are unsure.
2183 config FPROBE_SANITY_TEST
2184 bool "Self test for fprobe"
2185 depends on DEBUG_KERNEL
2189 This option will enable testing the fprobe when the system boot.
2190 A series of tests are made to verify that the fprobe is functioning
2193 Say N if you are unsure.
2195 config BACKTRACE_SELF_TEST
2196 tristate "Self test for the backtrace code"
2197 depends on DEBUG_KERNEL
2199 This option provides a kernel module that can be used to test
2200 the kernel stack backtrace code. This option is not useful
2201 for distributions or general kernels, but only for kernel
2202 developers working on architecture code.
2204 Note that if you want to also test saved backtraces, you will
2205 have to enable STACKTRACE as well.
2207 Say N if you are unsure.
2209 config TEST_REF_TRACKER
2210 tristate "Self test for reference tracker"
2211 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2214 This option provides a kernel module performing tests
2215 using reference tracker infrastructure.
2217 Say N if you are unsure.
2220 tristate "Red-Black tree test"
2221 depends on DEBUG_KERNEL
2223 A benchmark measuring the performance of the rbtree library.
2224 Also includes rbtree invariant checks.
2226 config REED_SOLOMON_TEST
2227 tristate "Reed-Solomon library test"
2228 depends on DEBUG_KERNEL || m
2230 select REED_SOLOMON_ENC16
2231 select REED_SOLOMON_DEC16
2233 This option enables the self-test function of rslib at boot,
2234 or at module load time.
2238 config INTERVAL_TREE_TEST
2239 tristate "Interval tree test"
2240 depends on DEBUG_KERNEL
2241 select INTERVAL_TREE
2243 A benchmark measuring the performance of the interval tree library
2246 tristate "Per cpu operations test"
2247 depends on m && DEBUG_KERNEL
2249 Enable this option to build test module which validates per-cpu
2254 config ATOMIC64_SELFTEST
2255 tristate "Perform an atomic64_t self-test"
2257 Enable this option to test the atomic64_t functions at boot or
2258 at module load time.
2262 config ASYNC_RAID6_TEST
2263 tristate "Self test for hardware accelerated raid6 recovery"
2264 depends on ASYNC_RAID6_RECOV
2267 This is a one-shot self test that permutes through the
2268 recovery of all the possible two disk failure scenarios for a
2269 N-disk array. Recovery is performed with the asynchronous
2270 raid6 recovery routines, and will optionally use an offload
2271 engine if one is available.
2276 tristate "Test functions located in the hexdump module at runtime"
2278 config STRING_SELFTEST
2279 tristate "Test string functions at runtime"
2281 config TEST_STRING_HELPERS
2282 tristate "Test functions located in the string_helpers module at runtime"
2285 tristate "Test kstrto*() family of functions at runtime"
2288 tristate "Test printf() family of functions at runtime"
2291 tristate "Test scanf() family of functions at runtime"
2294 tristate "Test bitmap_*() family of functions at runtime"
2296 Enable this option to test the bitmap functions at boot.
2301 tristate "Test functions located in the uuid module at runtime"
2304 tristate "Test the XArray code at runtime"
2306 config TEST_MAPLE_TREE
2307 depends on DEBUG_KERNEL
2308 select DEBUG_MAPLE_TREE
2309 tristate "Test the Maple Tree code at runtime"
2311 config TEST_RHASHTABLE
2312 tristate "Perform selftest on resizable hash table"
2314 Enable this option to test the rhashtable functions at boot.
2319 tristate "Perform selftest on IDA functions"
2322 tristate "Perform selftest on priority array manager"
2325 Enable this option to test priority array manager on boot
2330 config TEST_IRQ_TIMINGS
2331 bool "IRQ timings selftest"
2332 depends on IRQ_TIMINGS
2334 Enable this option to test the irq timings code on boot.
2339 tristate "Test module loading with 'hello world' module"
2342 This builds the "test_module" module that emits "Hello, world"
2343 on printk when loaded. It is designed to be used for basic
2344 evaluation of the module loading subsystem (for example when
2345 validating module verification). It lacks any extra dependencies,
2346 and will not normally be loaded by the system unless explicitly
2352 tristate "Test module for compilation of bitops operations"
2355 This builds the "test_bitops" module that is much like the
2356 TEST_LKM module except that it does a basic exercise of the
2357 set/clear_bit macros and get_count_order/long to make sure there are
2358 no compiler warnings from C=1 sparse checker or -Wextra
2359 compilations. It has no dependencies and doesn't run or load unless
2360 explicitly requested by name. for example: modprobe test_bitops.
2365 tristate "Test module for stress/performance analysis of vmalloc allocator"
2370 This builds the "test_vmalloc" module that should be used for
2371 stress and performance analysis. So, any new change for vmalloc
2372 subsystem can be evaluated from performance and stability point
2377 config TEST_USER_COPY
2378 tristate "Test user/kernel boundary protections"
2381 This builds the "test_user_copy" module that runs sanity checks
2382 on the copy_to/from_user infrastructure, making sure basic
2383 user/kernel boundary testing is working. If it fails to load,
2384 a regression has been detected in the user/kernel memory boundary
2390 tristate "Test BPF filter functionality"
2393 This builds the "test_bpf" module that runs various test vectors
2394 against the BPF interpreter or BPF JIT compiler depending on the
2395 current setting. This is in particular useful for BPF JIT compiler
2396 development, but also to run regression tests against changes in
2397 the interpreter code. It also enables test stubs for eBPF maps and
2398 verifier used by user space verifier testsuite.
2402 config TEST_BLACKHOLE_DEV
2403 tristate "Test blackhole netdev functionality"
2406 This builds the "test_blackhole_dev" module that validates the
2407 data path through this blackhole netdev.
2411 config FIND_BIT_BENCHMARK
2412 tristate "Test find_bit functions"
2414 This builds the "test_find_bit" module that measure find_*_bit()
2415 functions performance.
2419 config TEST_FIRMWARE
2420 tristate "Test firmware loading via userspace interface"
2421 depends on FW_LOADER
2423 This builds the "test_firmware" module that creates a userspace
2424 interface for testing firmware loading. This can be used to
2425 control the triggering of firmware loading without needing an
2426 actual firmware-using device. The contents can be rechecked by
2432 tristate "sysctl test driver"
2433 depends on PROC_SYSCTL
2435 This builds the "test_sysctl" module. This driver enables to test the
2436 proc sysctl interfaces available to drivers safely without affecting
2437 production knobs which might alter system functionality.
2441 config BITFIELD_KUNIT
2442 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2444 default KUNIT_ALL_TESTS
2446 Enable this option to test the bitfield functions at boot.
2448 KUnit tests run during boot and output the results to the debug log
2449 in TAP format (http://testanything.org/). Only useful for kernel devs
2450 running the KUnit test harness, and not intended for inclusion into a
2453 For more information on KUnit and unit tests in general please refer
2454 to the KUnit documentation in Documentation/dev-tools/kunit/.
2458 config HASH_KUNIT_TEST
2459 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2461 default KUNIT_ALL_TESTS
2463 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2464 integer (<linux/hash.h>) hash functions on boot.
2466 KUnit tests run during boot and output the results to the debug log
2467 in TAP format (https://testanything.org/). Only useful for kernel devs
2468 running the KUnit test harness, and not intended for inclusion into a
2471 For more information on KUnit and unit tests in general please refer
2472 to the KUnit documentation in Documentation/dev-tools/kunit/.
2474 This is intended to help people writing architecture-specific
2475 optimized versions. If unsure, say N.
2477 config RESOURCE_KUNIT_TEST
2478 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2480 default KUNIT_ALL_TESTS
2482 This builds the resource API unit test.
2483 Tests the logic of API provided by resource.c and ioport.h.
2484 For more information on KUnit and unit tests in general please refer
2485 to the KUnit documentation in Documentation/dev-tools/kunit/.
2489 config SYSCTL_KUNIT_TEST
2490 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2492 default KUNIT_ALL_TESTS
2494 This builds the proc sysctl unit test, which runs on boot.
2495 Tests the API contract and implementation correctness of sysctl.
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 LIST_KUNIT_TEST
2502 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2504 default KUNIT_ALL_TESTS
2506 This builds the linked list KUnit test suite.
2507 It tests that the API and basic functionality of the list_head type
2508 and associated macros.
2510 KUnit tests run during boot and output the results to the debug log
2511 in TAP format (https://testanything.org/). Only useful for kernel devs
2512 running the KUnit test harness, and not intended for inclusion into a
2515 For more information on KUnit and unit tests in general please refer
2516 to the KUnit documentation in Documentation/dev-tools/kunit/.
2520 config HASHTABLE_KUNIT_TEST
2521 tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS
2523 default KUNIT_ALL_TESTS
2525 This builds the hashtable KUnit test suite.
2526 It tests the basic functionality of the API defined in
2527 include/linux/hashtable.h. For more information on KUnit and
2528 unit tests in general please refer to the KUnit documentation
2529 in Documentation/dev-tools/kunit/.
2533 config LINEAR_RANGES_TEST
2534 tristate "KUnit test for linear_ranges"
2536 select LINEAR_RANGES
2538 This builds the linear_ranges unit test, which runs on boot.
2539 Tests the linear_ranges logic correctness.
2540 For more information on KUnit and unit tests in general please refer
2541 to the KUnit documentation in Documentation/dev-tools/kunit/.
2545 config CMDLINE_KUNIT_TEST
2546 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2548 default KUNIT_ALL_TESTS
2550 This builds the cmdline API unit test.
2551 Tests the logic of API provided by cmdline.c.
2552 For more information on KUnit and unit tests in general please refer
2553 to the KUnit documentation in Documentation/dev-tools/kunit/.
2558 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2560 default KUNIT_ALL_TESTS
2562 This builds the bits unit test.
2563 Tests the logic of macros defined in bits.h.
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 SLUB_KUNIT_TEST
2570 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2571 depends on SLUB_DEBUG && KUNIT
2572 default KUNIT_ALL_TESTS
2574 This builds SLUB allocator unit test.
2575 Tests SLUB cache debugging functionality.
2576 For more information on KUnit and unit tests in general please refer
2577 to the KUnit documentation in Documentation/dev-tools/kunit/.
2581 config RATIONAL_KUNIT_TEST
2582 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2583 depends on KUNIT && RATIONAL
2584 default KUNIT_ALL_TESTS
2586 This builds the rational math unit test.
2587 For more information on KUnit and unit tests in general please refer
2588 to the KUnit documentation in Documentation/dev-tools/kunit/.
2592 config MEMCPY_KUNIT_TEST
2593 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2595 default KUNIT_ALL_TESTS
2597 Builds unit tests for memcpy(), memmove(), and memset() functions.
2598 For more information on KUnit and unit tests in general please refer
2599 to the KUnit documentation in Documentation/dev-tools/kunit/.
2603 config MEMCPY_SLOW_KUNIT_TEST
2604 bool "Include exhaustive memcpy tests"
2605 depends on MEMCPY_KUNIT_TEST
2608 Some memcpy tests are quite exhaustive in checking for overlaps
2609 and bit ranges. These can be very slow, so they are split out
2610 as a separate config, in case they need to be disabled.
2612 config IS_SIGNED_TYPE_KUNIT_TEST
2613 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2615 default KUNIT_ALL_TESTS
2617 Builds unit tests for the is_signed_type() macro.
2619 For more information on KUnit and unit tests in general please refer
2620 to the KUnit documentation in Documentation/dev-tools/kunit/.
2624 config OVERFLOW_KUNIT_TEST
2625 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2627 default KUNIT_ALL_TESTS
2629 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2632 For more information on KUnit and unit tests in general please refer
2633 to the KUnit documentation in Documentation/dev-tools/kunit/.
2637 config STACKINIT_KUNIT_TEST
2638 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2640 default KUNIT_ALL_TESTS
2642 Test if the kernel is zero-initializing stack variables and
2643 padding. Coverage is controlled by compiler flags,
2644 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2645 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2646 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2648 config FORTIFY_KUNIT_TEST
2649 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2650 depends on KUNIT && FORTIFY_SOURCE
2651 default KUNIT_ALL_TESTS
2653 Builds unit tests for checking internals of FORTIFY_SOURCE as used
2654 by the str*() and mem*() family of functions. For testing runtime
2655 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2657 config HW_BREAKPOINT_KUNIT_TEST
2658 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2659 depends on HAVE_HW_BREAKPOINT
2661 default KUNIT_ALL_TESTS
2663 Tests for hw_breakpoint constraints accounting.
2667 config STRSCPY_KUNIT_TEST
2668 tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS
2670 default KUNIT_ALL_TESTS
2672 config SIPHASH_KUNIT_TEST
2673 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2675 default KUNIT_ALL_TESTS
2677 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2678 functions on boot (or module load).
2680 This is intended to help people writing architecture-specific
2681 optimized versions. If unsure, say N.
2684 tristate "udelay test driver"
2686 This builds the "udelay_test" module that helps to make sure
2687 that udelay() is working properly.
2691 config TEST_STATIC_KEYS
2692 tristate "Test static keys"
2695 Test the static key interfaces.
2699 config TEST_DYNAMIC_DEBUG
2700 tristate "Test DYNAMIC_DEBUG"
2701 depends on DYNAMIC_DEBUG
2703 This module registers a tracer callback to count enabled
2704 pr_debugs in a 'do_debugging' function, then alters their
2705 enablements, calls the function, and compares counts.
2710 tristate "kmod stress tester"
2712 depends on NETDEVICES && NET_CORE && INET # for TUN
2714 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2720 Test the kernel's module loading mechanism: kmod. kmod implements
2721 support to load modules using the Linux kernel's usermode helper.
2722 This test provides a series of tests against kmod.
2724 Although technically you can either build test_kmod as a module or
2725 into the kernel we disallow building it into the kernel since
2726 it stress tests request_module() and this will very likely cause
2727 some issues by taking over precious threads available from other
2728 module load requests, ultimately this could be fatal.
2732 tools/testing/selftests/kmod/kmod.sh --help
2736 config TEST_DEBUG_VIRTUAL
2737 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2738 depends on DEBUG_VIRTUAL
2740 Test the kernel's ability to detect incorrect calls to
2741 virt_to_phys() done against the non-linear part of the
2742 kernel's virtual address map.
2746 config TEST_MEMCAT_P
2747 tristate "Test memcat_p() helper function"
2749 Test the memcat_p() helper for correctly merging two
2750 pointer arrays together.
2754 config TEST_LIVEPATCH
2755 tristate "Test livepatching"
2757 depends on DYNAMIC_DEBUG
2758 depends on LIVEPATCH
2761 Test kernel livepatching features for correctness. The tests will
2762 load test modules that will be livepatched in various scenarios.
2764 To run all the livepatching tests:
2766 make -C tools/testing/selftests TARGETS=livepatch run_tests
2768 Alternatively, individual tests may be invoked:
2770 tools/testing/selftests/livepatch/test-callbacks.sh
2771 tools/testing/selftests/livepatch/test-livepatch.sh
2772 tools/testing/selftests/livepatch/test-shadow-vars.sh
2777 tristate "Perform selftest on object aggreration manager"
2781 Enable this option to test object aggregation manager on boot
2785 tristate "Test heap/page initialization"
2787 Test if the kernel is zero-initializing heap and page allocations.
2788 This can be useful to test init_on_alloc and init_on_free features.
2793 tristate "Test HMM (Heterogeneous Memory Management)"
2794 depends on TRANSPARENT_HUGEPAGE
2795 depends on DEVICE_PRIVATE
2799 This is a pseudo device driver solely for testing HMM.
2800 Say M here if you want to build the HMM test module.
2801 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2805 config TEST_FREE_PAGES
2806 tristate "Test freeing pages"
2808 Test that a memory leak does not occur due to a race between
2809 freeing a block of pages and a speculative page reference.
2810 Loading this module is safe if your kernel has the bug fixed.
2811 If the bug is not fixed, it will leak gigabytes of memory and
2812 probably OOM your system.
2815 tristate "Test floating point operations in kernel space"
2816 depends on X86 && !KCOV_INSTRUMENT_ALL
2818 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2819 which will trigger a sequence of floating point operations. This is used
2820 for self-testing floating point control register setting in
2825 config TEST_CLOCKSOURCE_WATCHDOG
2826 tristate "Test clocksource watchdog in kernel space"
2827 depends on CLOCKSOURCE_WATCHDOG
2829 Enable this option to create a kernel module that will trigger
2830 a test of the clocksource watchdog. This module may be loaded
2831 via modprobe or insmod in which case it will run upon being
2832 loaded, or it may be built in, in which case it will run
2837 endif # RUNTIME_TESTING_MENU
2839 config ARCH_USE_MEMTEST
2842 An architecture should select this when it uses early_memtest()
2843 during boot process.
2847 depends on ARCH_USE_MEMTEST
2849 This option adds a kernel parameter 'memtest', which allows memtest
2850 to be set and executed.
2851 memtest=0, mean disabled; -- default
2852 memtest=1, mean do 1 test pattern;
2854 memtest=17, mean do 17 test patterns.
2855 If you are unsure how to answer this question, answer N.
2859 config HYPERV_TESTING
2860 bool "Microsoft Hyper-V driver testing"
2862 depends on HYPERV && DEBUG_FS
2864 Select this option to enable Hyper-V vmbus testing.
2866 endmenu # "Kernel Testing and Coverage"
2870 config RUST_DEBUG_ASSERTIONS
2871 bool "Debug assertions"
2874 Enables rustc's `-Cdebug-assertions` codegen option.
2876 This flag lets you turn `cfg(debug_assertions)` conditional
2877 compilation on or off. This can be used to enable extra debugging
2878 code in development but not in production. For example, it controls
2879 the behavior of the standard library's `debug_assert!` macro.
2881 Note that this will apply to all Rust code, including `core`.
2885 config RUST_OVERFLOW_CHECKS
2886 bool "Overflow checks"
2890 Enables rustc's `-Coverflow-checks` codegen option.
2892 This flag allows you to control the behavior of runtime integer
2893 overflow. When overflow-checks are enabled, a Rust panic will occur
2896 Note that this will apply to all Rust code, including `core`.
2900 config RUST_BUILD_ASSERT_ALLOW
2901 bool "Allow unoptimized build-time assertions"
2904 Controls how are `build_error!` and `build_assert!` handled during build.
2906 If calls to them exist in the binary, it may indicate a violated invariant
2907 or that the optimizer failed to verify the invariant during compilation.
2909 This should not happen, thus by default the build is aborted. However,
2910 as an escape hatch, you can choose Y here to ignore them during build
2911 and let the check be carried at runtime (with `panic!` being called if
2918 endmenu # Kernel hacking
projects / linux-2.6-microblaze.git / blob