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 generates .uleb128 with label differences for DWARF v5, a feature that
235 # older binutils ports do not support when utilizing RISC-V style linker
236 # relaxation: https://sourceware.org/bugzilla/show_bug.cgi?id=27215
237 config AS_HAS_NON_CONST_ULEB128
238 def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:)
241 prompt "Debug information"
242 depends on DEBUG_KERNEL
244 Selecting something other than "None" results in a kernel image
245 that will include debugging info resulting in a larger kernel image.
246 This adds debug symbols to the kernel and modules (gcc -g), and
247 is needed if you intend to use kernel crashdump or binary object
248 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
250 Choose which version of DWARF debug info to emit. If unsure,
251 select "Toolchain default".
253 config DEBUG_INFO_NONE
254 bool "Disable debug information"
256 Do not build the kernel with debugging information, which will
257 result in a faster and smaller build.
259 config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
260 bool "Rely on the toolchain's implicit default DWARF version"
262 depends on !CC_IS_CLANG || AS_IS_LLVM || CLANG_VERSION < 140000 || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128)
264 The implicit default version of DWARF debug info produced by a
265 toolchain changes over time.
267 This can break consumers of the debug info that haven't upgraded to
268 support newer revisions, and prevent testing newer versions, but
269 those should be less common scenarios.
271 config DEBUG_INFO_DWARF4
272 bool "Generate DWARF Version 4 debuginfo"
274 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)
276 Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2
277 if using clang without clang's integrated assembler, and gdb 7.0+.
279 If you have consumers of DWARF debug info that are not ready for
280 newer revisions of DWARF, you may wish to choose this or have your
283 config DEBUG_INFO_DWARF5
284 bool "Generate DWARF Version 5 debuginfo"
286 depends on !ARCH_HAS_BROKEN_DWARF5
287 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128)
289 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
290 5.0+ accepts the -gdwarf-5 flag but only had partial support for some
291 draft features until 7.0), and gdb 8.0+.
293 Changes to the structure of debug info in Version 5 allow for around
294 15-18% savings in resulting image and debug info section sizes as
295 compared to DWARF Version 4. DWARF Version 5 standardizes previous
296 extensions such as accelerators for symbol indexing and the format
297 for fission (.dwo/.dwp) files. Users may not want to select this
298 config if they rely on tooling that has not yet been updated to
299 support DWARF Version 5.
301 endchoice # "Debug information"
305 config DEBUG_INFO_REDUCED
306 bool "Reduce debugging information"
308 If you say Y here gcc is instructed to generate less debugging
309 information for structure types. This means that tools that
310 need full debugging information (like kgdb or systemtap) won't
311 be happy. But if you merely need debugging information to
312 resolve line numbers there is no loss. Advantage is that
313 build directory object sizes shrink dramatically over a full
314 DEBUG_INFO build and compile times are reduced too.
315 Only works with newer gcc versions.
318 prompt "Compressed Debug information"
320 Compress the resulting debug info. Results in smaller debug info sections,
321 but requires that consumers are able to decompress the results.
323 If unsure, choose DEBUG_INFO_COMPRESSED_NONE.
325 config DEBUG_INFO_COMPRESSED_NONE
326 bool "Don't compress debug information"
328 Don't compress debug info sections.
330 config DEBUG_INFO_COMPRESSED_ZLIB
331 bool "Compress debugging information with zlib"
332 depends on $(cc-option,-gz=zlib)
333 depends on $(ld-option,--compress-debug-sections=zlib)
335 Compress the debug information using zlib. Requires GCC 5.0+ or Clang
336 5.0+, binutils 2.26+, and zlib.
338 Users of dpkg-deb via scripts/package/builddeb may find an increase in
339 size of their debug .deb packages with this config set, due to the
340 debug info being compressed with zlib, then the object files being
341 recompressed with a different compression scheme. But this is still
342 preferable to setting $KDEB_COMPRESS to "none" which would be even
345 config DEBUG_INFO_COMPRESSED_ZSTD
346 bool "Compress debugging information with zstd"
347 depends on $(cc-option,-gz=zstd)
348 depends on $(ld-option,--compress-debug-sections=zstd)
350 Compress the debug information using zstd. This may provide better
351 compression than zlib, for about the same time costs, but requires newer
352 toolchain support. Requires GCC 13.0+ or Clang 16.0+, binutils 2.40+, and
355 endchoice # "Compressed Debug information"
357 config DEBUG_INFO_SPLIT
358 bool "Produce split debuginfo in .dwo files"
359 depends on $(cc-option,-gsplit-dwarf)
360 # RISC-V linker relaxation + -gsplit-dwarf has issues with LLVM and GCC
362 # https://github.com/llvm/llvm-project/issues/56642
363 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99090
364 depends on !RISCV || GCC_VERSION >= 120000
366 Generate debug info into separate .dwo files. This significantly
367 reduces the build directory size for builds with DEBUG_INFO,
368 because it stores the information only once on disk in .dwo
369 files instead of multiple times in object files and executables.
370 In addition the debug information is also compressed.
372 Requires recent gcc (4.7+) and recent gdb/binutils.
373 Any tool that packages or reads debug information would need
374 to know about the .dwo files and include them.
375 Incompatible with older versions of ccache.
377 config DEBUG_INFO_BTF
378 bool "Generate BTF type information"
379 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
380 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
381 depends on BPF_SYSCALL
382 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121
383 # pahole uses elfutils, which does not have support for Hexagon relocations
386 Generate deduplicated BTF type information from DWARF debug info.
387 Turning this on expects presence of pahole tool, which will convert
388 DWARF type info into equivalent deduplicated BTF type info.
390 config PAHOLE_HAS_SPLIT_BTF
391 def_bool PAHOLE_VERSION >= 119
393 config PAHOLE_HAS_BTF_TAG
394 def_bool PAHOLE_VERSION >= 123
395 depends on CC_IS_CLANG
397 Decide whether pahole emits btf_tag attributes (btf_type_tag and
398 btf_decl_tag) or not. Currently only clang compiler implements
399 these attributes, so make the config depend on CC_IS_CLANG.
401 config PAHOLE_HAS_LANG_EXCLUDE
402 def_bool PAHOLE_VERSION >= 124
404 Support for the --lang_exclude flag which makes pahole exclude
405 compilation units from the supplied language. Used in Kbuild to
406 omit Rust CUs which are not supported in version 1.24 of pahole,
407 otherwise it would emit malformed kernel and module binaries when
408 using DEBUG_INFO_BTF_MODULES.
410 config DEBUG_INFO_BTF_MODULES
411 bool "Generate BTF type information for kernel modules"
413 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
415 Generate compact split BTF type information for kernel modules.
417 config MODULE_ALLOW_BTF_MISMATCH
418 bool "Allow loading modules with non-matching BTF type info"
419 depends on DEBUG_INFO_BTF_MODULES
421 For modules whose split BTF does not match vmlinux, load without
422 BTF rather than refusing to load. The default behavior with
423 module BTF enabled is to reject modules with such mismatches;
424 this option will still load module BTF where possible but ignore
425 it when a mismatch is found.
428 bool "Provide GDB scripts for kernel debugging"
430 This creates the required links to GDB helper scripts in the
431 build directory. If you load vmlinux into gdb, the helper
432 scripts will be automatically imported by gdb as well, and
433 additional functions are available to analyze a Linux kernel
434 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
440 int "Warn for stack frames larger than"
443 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
444 default 2048 if PARISC
445 default 1536 if (!64BIT && XTENSA)
446 default 1280 if KASAN && !64BIT
447 default 1024 if !64BIT
448 default 2048 if 64BIT
450 Tell the compiler to warn at build time for stack frames larger than this.
451 Setting this too low will cause a lot of warnings.
452 Setting it to 0 disables the warning.
454 config STRIP_ASM_SYMS
455 bool "Strip assembler-generated symbols during link"
458 Strip internal assembler-generated symbols during a link (symbols
459 that look like '.Lxxx') so they don't pollute the output of
460 get_wchan() and suchlike.
463 bool "Generate readable assembler code"
464 depends on DEBUG_KERNEL
467 Disable some compiler optimizations that tend to generate human unreadable
468 assembler output. This may make the kernel slightly slower, but it helps
469 to keep kernel developers who have to stare a lot at assembler listings
472 config HEADERS_INSTALL
473 bool "Install uapi headers to usr/include"
476 This option will install uapi headers (headers exported to user-space)
477 into the usr/include directory for use during the kernel build.
478 This is unneeded for building the kernel itself, but needed for some
479 user-space program samples. It is also needed by some features such
480 as uapi header sanity checks.
482 config DEBUG_SECTION_MISMATCH
483 bool "Enable full Section mismatch analysis"
486 The section mismatch analysis checks if there are illegal
487 references from one section to another section.
488 During linktime or runtime, some sections are dropped;
489 any use of code/data previously in these sections would
490 most likely result in an oops.
491 In the code, functions and variables are annotated with
492 __init,, etc. (see the full list in include/linux/init.h),
493 which results in the code/data being placed in specific sections.
494 The section mismatch analysis is always performed after a full
495 kernel build, and enabling this option causes the following
496 additional step to occur:
497 - Add the option -fno-inline-functions-called-once to gcc commands.
498 When inlining a function annotated with __init in a non-init
499 function, we would lose the section information and thus
500 the analysis would not catch the illegal reference.
501 This option tells gcc to inline less (but it does result in
504 config SECTION_MISMATCH_WARN_ONLY
505 bool "Make section mismatch errors non-fatal"
508 If you say N here, the build process will fail if there are any
509 section mismatch, instead of just throwing warnings.
513 config DEBUG_FORCE_FUNCTION_ALIGN_64B
514 bool "Force all function address 64B aligned"
515 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC || RISCV || S390)
516 select FUNCTION_ALIGNMENT_64B
518 There are cases that a commit from one domain changes the function
519 address alignment of other domains, and cause magic performance
520 bump (regression or improvement). Enable this option will help to
521 verify if the bump is caused by function alignment changes, while
522 it will slightly increase the kernel size and affect icache usage.
524 It is mainly for debug and performance tuning use.
527 # Select this config option from the architecture Kconfig, if it
528 # is preferred to always offer frame pointers as a config
529 # option on the architecture (regardless of KERNEL_DEBUG):
531 config ARCH_WANT_FRAME_POINTERS
535 bool "Compile the kernel with frame pointers"
536 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
537 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
539 If you say Y here the resulting kernel image will be slightly
540 larger and slower, but it gives very useful debugging information
541 in case of kernel bugs. (precise oopses/stacktraces/warnings)
546 config STACK_VALIDATION
547 bool "Compile-time stack metadata validation"
548 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
552 Validate frame pointer rules at compile-time. This helps ensure that
553 runtime stack traces are more reliable.
555 For more information, see
556 tools/objtool/Documentation/objtool.txt.
558 config NOINSTR_VALIDATION
560 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
565 bool "Generate vmlinux.map file when linking"
568 Selecting this option will pass "-Map=vmlinux.map" to ld
569 when linking vmlinux. That file can be useful for verifying
570 and debugging magic section games, and for seeing which
571 pieces of code get eliminated with
572 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
574 config DEBUG_FORCE_WEAK_PER_CPU
575 bool "Force weak per-cpu definitions"
576 depends on DEBUG_KERNEL
578 s390 and alpha require percpu variables in modules to be
579 defined weak to work around addressing range issue which
580 puts the following two restrictions on percpu variable
583 1. percpu symbols must be unique whether static or not
584 2. percpu variables can't be defined inside a function
586 To ensure that generic code follows the above rules, this
587 option forces all percpu variables to be defined as weak.
589 endmenu # "Compiler options"
591 menu "Generic Kernel Debugging Instruments"
594 bool "Magic SysRq key"
597 If you say Y here, you will have some control over the system even
598 if the system crashes for example during kernel debugging (e.g., you
599 will be able to flush the buffer cache to disk, reboot the system
600 immediately or dump some status information). This is accomplished
601 by pressing various keys while holding SysRq (Alt+PrintScreen). It
602 also works on a serial console (on PC hardware at least), if you
603 send a BREAK and then within 5 seconds a command keypress. The
604 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
605 Don't say Y unless you really know what this hack does.
607 config MAGIC_SYSRQ_DEFAULT_ENABLE
608 hex "Enable magic SysRq key functions by default"
609 depends on MAGIC_SYSRQ
612 Specifies which SysRq key functions are enabled by default.
613 This may be set to 1 or 0 to enable or disable them all, or
614 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
616 config MAGIC_SYSRQ_SERIAL
617 bool "Enable magic SysRq key over serial"
618 depends on MAGIC_SYSRQ
621 Many embedded boards have a disconnected TTL level serial which can
622 generate some garbage that can lead to spurious false sysrq detects.
623 This option allows you to decide whether you want to enable the
626 config MAGIC_SYSRQ_SERIAL_SEQUENCE
627 string "Char sequence that enables magic SysRq over serial"
628 depends on MAGIC_SYSRQ_SERIAL
631 Specifies a sequence of characters that can follow BREAK to enable
632 SysRq on a serial console.
634 If unsure, leave an empty string and the option will not be enabled.
637 bool "Debug Filesystem"
639 debugfs is a virtual file system that kernel developers use to put
640 debugging files into. Enable this option to be able to read and
641 write to these files.
643 For detailed documentation on the debugfs API, see
644 Documentation/filesystems/.
649 prompt "Debugfs default access"
651 default DEBUG_FS_ALLOW_ALL
653 This selects the default access restrictions for debugfs.
654 It can be overridden with kernel command line option
655 debugfs=[on,no-mount,off]. The restrictions apply for API access
656 and filesystem registration.
658 config DEBUG_FS_ALLOW_ALL
661 No restrictions apply. Both API and filesystem registration
662 is on. This is the normal default operation.
664 config DEBUG_FS_DISALLOW_MOUNT
665 bool "Do not register debugfs as filesystem"
667 The API is open but filesystem is not loaded. Clients can still do
668 their work and read with debug tools that do not need
671 config DEBUG_FS_ALLOW_NONE
674 Access is off. Clients get -PERM when trying to create nodes in
675 debugfs tree and debugfs is not registered as a filesystem.
676 Client can then back-off or continue without debugfs access.
680 source "lib/Kconfig.kgdb"
681 source "lib/Kconfig.ubsan"
682 source "lib/Kconfig.kcsan"
686 menu "Networking Debugging"
688 source "net/Kconfig.debug"
690 endmenu # "Networking Debugging"
692 menu "Memory Debugging"
694 source "mm/Kconfig.debug"
697 bool "Debug object operations"
698 depends on DEBUG_KERNEL
700 If you say Y here, additional code will be inserted into the
701 kernel to track the life time of various objects and validate
702 the operations on those objects.
704 config DEBUG_OBJECTS_SELFTEST
705 bool "Debug objects selftest"
706 depends on DEBUG_OBJECTS
708 This enables the selftest of the object debug code.
710 config DEBUG_OBJECTS_FREE
711 bool "Debug objects in freed memory"
712 depends on DEBUG_OBJECTS
714 This enables checks whether a k/v free operation frees an area
715 which contains an object which has not been deactivated
716 properly. This can make kmalloc/kfree-intensive workloads
719 config DEBUG_OBJECTS_TIMERS
720 bool "Debug timer objects"
721 depends on DEBUG_OBJECTS
723 If you say Y here, additional code will be inserted into the
724 timer routines to track the life time of timer objects and
725 validate the timer operations.
727 config DEBUG_OBJECTS_WORK
728 bool "Debug work objects"
729 depends on DEBUG_OBJECTS
731 If you say Y here, additional code will be inserted into the
732 work queue routines to track the life time of work objects and
733 validate the work operations.
735 config DEBUG_OBJECTS_RCU_HEAD
736 bool "Debug RCU callbacks objects"
737 depends on DEBUG_OBJECTS
739 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
741 config DEBUG_OBJECTS_PERCPU_COUNTER
742 bool "Debug percpu counter objects"
743 depends on DEBUG_OBJECTS
745 If you say Y here, additional code will be inserted into the
746 percpu counter routines to track the life time of percpu counter
747 objects and validate the percpu counter operations.
749 config DEBUG_OBJECTS_ENABLE_DEFAULT
750 int "debug_objects bootup default value (0-1)"
753 depends on DEBUG_OBJECTS
755 Debug objects boot parameter default value
757 config SHRINKER_DEBUG
758 bool "Enable shrinker debugging support"
761 Say Y to enable the shrinker debugfs interface which provides
762 visibility into the kernel memory shrinkers subsystem.
763 Disable it to avoid an extra memory footprint.
765 config DEBUG_STACK_USAGE
766 bool "Stack utilization instrumentation"
767 depends on DEBUG_KERNEL
769 Enables the display of the minimum amount of free stack which each
770 task has ever had available in the sysrq-T and sysrq-P debug output.
771 Also emits a message to dmesg when a process exits if that process
772 used more stack space than previously exiting processes.
774 This option will slow down process creation somewhat.
776 config SCHED_STACK_END_CHECK
777 bool "Detect stack corruption on calls to schedule()"
778 depends on DEBUG_KERNEL
781 This option checks for a stack overrun on calls to schedule().
782 If the stack end location is found to be over written always panic as
783 the content of the corrupted region can no longer be trusted.
784 This is to ensure no erroneous behaviour occurs which could result in
785 data corruption or a sporadic crash at a later stage once the region
786 is examined. The runtime overhead introduced is minimal.
788 config ARCH_HAS_DEBUG_VM_PGTABLE
791 An architecture should select this when it can successfully
792 build and run DEBUG_VM_PGTABLE.
794 config DEBUG_VM_IRQSOFF
795 def_bool DEBUG_VM && !PREEMPT_RT
799 depends on DEBUG_KERNEL
801 Enable this to turn on extended checks in the virtual-memory system
802 that may impact performance.
806 config DEBUG_VM_SHOOT_LAZIES
807 bool "Debug MMU_LAZY_TLB_SHOOTDOWN implementation"
809 depends on MMU_LAZY_TLB_SHOOTDOWN
811 Enable additional IPIs that ensure lazy tlb mm references are removed
812 before the mm is freed.
816 config DEBUG_VM_MAPLE_TREE
817 bool "Debug VM maple trees"
819 select DEBUG_MAPLE_TREE
821 Enable VM maple tree debugging information and extra validations.
826 bool "Debug VM red-black trees"
829 Enable VM red-black tree debugging information and extra validations.
833 config DEBUG_VM_PGFLAGS
834 bool "Debug page-flags operations"
837 Enables extra validation on page flags operations.
841 config DEBUG_VM_PGTABLE
842 bool "Debug arch page table for semantics compliance"
844 depends on ARCH_HAS_DEBUG_VM_PGTABLE
845 default y if DEBUG_VM
847 This option provides a debug method which can be used to test
848 architecture page table helper functions on various platforms in
849 verifying if they comply with expected generic MM semantics. This
850 will help architecture code in making sure that any changes or
851 new additions of these helpers still conform to expected
852 semantics of the generic MM. Platforms will have to opt in for
853 this through ARCH_HAS_DEBUG_VM_PGTABLE.
857 config ARCH_HAS_DEBUG_VIRTUAL
861 bool "Debug VM translations"
862 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
864 Enable some costly sanity checks in virtual to page code. This can
865 catch mistakes with virt_to_page() and friends.
869 config DEBUG_NOMMU_REGIONS
870 bool "Debug the global anon/private NOMMU mapping region tree"
871 depends on DEBUG_KERNEL && !MMU
873 This option causes the global tree of anonymous and private mapping
874 regions to be regularly checked for invalid topology.
876 config DEBUG_MEMORY_INIT
877 bool "Debug memory initialisation" if EXPERT
880 Enable this for additional checks during memory initialisation.
881 The sanity checks verify aspects of the VM such as the memory model
882 and other information provided by the architecture. Verbose
883 information will be printed at KERN_DEBUG loglevel depending
884 on the mminit_loglevel= command-line option.
888 config MEMORY_NOTIFIER_ERROR_INJECT
889 tristate "Memory hotplug notifier error injection module"
890 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
892 This option provides the ability to inject artificial errors to
893 memory hotplug notifier chain callbacks. It is controlled through
894 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
896 If the notifier call chain should be failed with some events
897 notified, write the error code to "actions/<notifier event>/error".
899 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
901 # cd /sys/kernel/debug/notifier-error-inject/memory
902 # echo -12 > actions/MEM_GOING_OFFLINE/error
903 # echo offline > /sys/devices/system/memory/memoryXXX/state
904 bash: echo: write error: Cannot allocate memory
906 To compile this code as a module, choose M here: the module will
907 be called memory-notifier-error-inject.
911 config DEBUG_PER_CPU_MAPS
912 bool "Debug access to per_cpu maps"
913 depends on DEBUG_KERNEL
916 Say Y to verify that the per_cpu map being accessed has
917 been set up. This adds a fair amount of code to kernel memory
918 and decreases performance.
922 config DEBUG_KMAP_LOCAL
923 bool "Debug kmap_local temporary mappings"
924 depends on DEBUG_KERNEL && KMAP_LOCAL
926 This option enables additional error checking for the kmap_local
927 infrastructure. Disable for production use.
929 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
932 config DEBUG_KMAP_LOCAL_FORCE_MAP
933 bool "Enforce kmap_local temporary mappings"
934 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
936 select DEBUG_KMAP_LOCAL
938 This option enforces temporary mappings through the kmap_local
939 mechanism for non-highmem pages and on non-highmem systems.
940 Disable this for production systems!
943 bool "Highmem debugging"
944 depends on DEBUG_KERNEL && HIGHMEM
945 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
946 select DEBUG_KMAP_LOCAL
948 This option enables additional error checking for high memory
949 systems. Disable for production systems.
951 config HAVE_DEBUG_STACKOVERFLOW
954 config DEBUG_STACKOVERFLOW
955 bool "Check for stack overflows"
956 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
958 Say Y here if you want to check for overflows of kernel, IRQ
959 and exception stacks (if your architecture uses them). This
960 option will show detailed messages if free stack space drops
961 below a certain limit.
963 These kinds of bugs usually occur when call-chains in the
964 kernel get too deep, especially when interrupts are
967 Use this in cases where you see apparently random memory
968 corruption, especially if it appears in 'struct thread_info'
970 If in doubt, say "N".
976 config MEM_ALLOC_PROFILING
977 bool "Enable memory allocation profiling"
980 depends on !DEBUG_FORCE_WEAK_PER_CPU
982 select PAGE_EXTENSION
985 Track allocation source code and record total allocation size
986 initiated at that code location. The mechanism can be used to track
987 memory leaks with a low performance and memory impact.
989 config MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
990 bool "Enable memory allocation profiling by default"
992 depends on MEM_ALLOC_PROFILING
994 config MEM_ALLOC_PROFILING_DEBUG
995 bool "Memory allocation profiler debugging"
997 depends on MEM_ALLOC_PROFILING
998 select MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
1000 Adds warnings with helpful error messages for memory allocation
1003 source "lib/Kconfig.kasan"
1004 source "lib/Kconfig.kfence"
1005 source "lib/Kconfig.kmsan"
1007 endmenu # "Memory Debugging"
1010 bool "Debug shared IRQ handlers"
1011 depends on DEBUG_KERNEL
1013 Enable this to generate a spurious interrupt just before a shared
1014 interrupt handler is deregistered (generating one when registering
1015 is currently disabled). Drivers need to handle this correctly. Some
1016 don't and need to be caught.
1018 menu "Debug Oops, Lockups and Hangs"
1020 config PANIC_ON_OOPS
1021 bool "Panic on Oops"
1023 Say Y here to enable the kernel to panic when it oopses. This
1024 has the same effect as setting oops=panic on the kernel command
1027 This feature is useful to ensure that the kernel does not do
1028 anything erroneous after an oops which could result in data
1029 corruption or other issues.
1033 config PANIC_ON_OOPS_VALUE
1036 default 0 if !PANIC_ON_OOPS
1037 default 1 if PANIC_ON_OOPS
1039 config PANIC_TIMEOUT
1043 Set the timeout value (in seconds) until a reboot occurs when
1044 the kernel panics. If n = 0, then we wait forever. A timeout
1045 value n > 0 will wait n seconds before rebooting, while a timeout
1046 value n < 0 will reboot immediately. This setting can be overridden
1047 with the kernel command line option panic=, and from userspace via
1048 /proc/sys/kernel/panic.
1050 config LOCKUP_DETECTOR
1053 config SOFTLOCKUP_DETECTOR
1054 bool "Detect Soft Lockups"
1055 depends on DEBUG_KERNEL && !S390
1056 select LOCKUP_DETECTOR
1058 Say Y here to enable the kernel to act as a watchdog to detect
1061 Softlockups are bugs that cause the kernel to loop in kernel
1062 mode for more than 20 seconds, without giving other tasks a
1063 chance to run. The current stack trace is displayed upon
1064 detection and the system will stay locked up.
1066 config SOFTLOCKUP_DETECTOR_INTR_STORM
1067 bool "Detect Interrupt Storm in Soft Lockups"
1068 depends on SOFTLOCKUP_DETECTOR && IRQ_TIME_ACCOUNTING
1069 select GENERIC_IRQ_STAT_SNAPSHOT
1070 default y if NR_CPUS <= 128
1072 Say Y here to enable the kernel to detect interrupt storm
1073 during "soft lockups".
1075 "soft lockups" can be caused by a variety of reasons. If one is
1076 caused by an interrupt storm, then the storming interrupts will not
1077 be on the callstack. To detect this case, it is necessary to report
1078 the CPU stats and the interrupt counts during the "soft lockups".
1080 config BOOTPARAM_SOFTLOCKUP_PANIC
1081 bool "Panic (Reboot) On Soft Lockups"
1082 depends on SOFTLOCKUP_DETECTOR
1084 Say Y here to enable the kernel to panic on "soft lockups",
1085 which are bugs that cause the kernel to loop in kernel
1086 mode for more than 20 seconds (configurable using the watchdog_thresh
1087 sysctl), without giving other tasks a chance to run.
1089 The panic can be used in combination with panic_timeout,
1090 to cause the system to reboot automatically after a
1091 lockup has been detected. This feature is useful for
1092 high-availability systems that have uptime guarantees and
1093 where a lockup must be resolved ASAP.
1097 config HAVE_HARDLOCKUP_DETECTOR_BUDDY
1103 # Global switch whether to build a hardlockup detector at all. It is available
1104 # only when the architecture supports at least one implementation. There are
1105 # two exceptions. The hardlockup detector is never enabled on:
1107 # s390: it reported many false positives there
1109 # sparc64: has a custom implementation which is not using the common
1110 # hardlockup command line options and sysctl interface.
1112 config HARDLOCKUP_DETECTOR
1113 bool "Detect Hard Lockups"
1114 depends on DEBUG_KERNEL && !S390 && !HARDLOCKUP_DETECTOR_SPARC64
1115 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_BUDDY || HAVE_HARDLOCKUP_DETECTOR_ARCH
1116 imply HARDLOCKUP_DETECTOR_PERF
1117 imply HARDLOCKUP_DETECTOR_BUDDY
1118 imply HARDLOCKUP_DETECTOR_ARCH
1119 select LOCKUP_DETECTOR
1122 Say Y here to enable the kernel to act as a watchdog to detect
1125 Hardlockups are bugs that cause the CPU to loop in kernel mode
1126 for more than 10 seconds, without letting other interrupts have a
1127 chance to run. The current stack trace is displayed upon detection
1128 and the system will stay locked up.
1131 # Note that arch-specific variants are always preferred.
1133 config HARDLOCKUP_DETECTOR_PREFER_BUDDY
1134 bool "Prefer the buddy CPU hardlockup detector"
1135 depends on HARDLOCKUP_DETECTOR
1136 depends on HAVE_HARDLOCKUP_DETECTOR_PERF && HAVE_HARDLOCKUP_DETECTOR_BUDDY
1137 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1139 Say Y here to prefer the buddy hardlockup detector over the perf one.
1141 With the buddy detector, each CPU uses its softlockup hrtimer
1142 to check that the next CPU is processing hrtimer interrupts by
1143 verifying that a counter is increasing.
1145 This hardlockup detector is useful on systems that don't have
1146 an arch-specific hardlockup detector or if resources needed
1147 for the hardlockup detector are better used for other things.
1149 config HARDLOCKUP_DETECTOR_PERF
1151 depends on HARDLOCKUP_DETECTOR
1152 depends on HAVE_HARDLOCKUP_DETECTOR_PERF && !HARDLOCKUP_DETECTOR_PREFER_BUDDY
1153 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1154 select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1156 config HARDLOCKUP_DETECTOR_BUDDY
1158 depends on HARDLOCKUP_DETECTOR
1159 depends on HAVE_HARDLOCKUP_DETECTOR_BUDDY
1160 depends on !HAVE_HARDLOCKUP_DETECTOR_PERF || HARDLOCKUP_DETECTOR_PREFER_BUDDY
1161 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH
1162 select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1164 config HARDLOCKUP_DETECTOR_ARCH
1166 depends on HARDLOCKUP_DETECTOR
1167 depends on HAVE_HARDLOCKUP_DETECTOR_ARCH
1169 The arch-specific implementation of the hardlockup detector will
1173 # Both the "perf" and "buddy" hardlockup detectors count hrtimer
1174 # interrupts. This config enables functions managing this common code.
1176 config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER
1178 select SOFTLOCKUP_DETECTOR
1181 # Enables a timestamp based low pass filter to compensate for perf based
1182 # hard lockup detection which runs too fast due to turbo modes.
1184 config HARDLOCKUP_CHECK_TIMESTAMP
1187 config BOOTPARAM_HARDLOCKUP_PANIC
1188 bool "Panic (Reboot) On Hard Lockups"
1189 depends on HARDLOCKUP_DETECTOR
1191 Say Y here to enable the kernel to panic on "hard lockups",
1192 which are bugs that cause the kernel to loop in kernel
1193 mode with interrupts disabled for more than 10 seconds (configurable
1194 using the watchdog_thresh sysctl).
1198 config DETECT_HUNG_TASK
1199 bool "Detect Hung Tasks"
1200 depends on DEBUG_KERNEL
1201 default SOFTLOCKUP_DETECTOR
1203 Say Y here to enable the kernel to detect "hung tasks",
1204 which are bugs that cause the task to be stuck in
1205 uninterruptible "D" state indefinitely.
1207 When a hung task is detected, the kernel will print the
1208 current stack trace (which you should report), but the
1209 task will stay in uninterruptible state. If lockdep is
1210 enabled then all held locks will also be reported. This
1211 feature has negligible overhead.
1213 config DEFAULT_HUNG_TASK_TIMEOUT
1214 int "Default timeout for hung task detection (in seconds)"
1215 depends on DETECT_HUNG_TASK
1218 This option controls the default timeout (in seconds) used
1219 to determine when a task has become non-responsive and should
1222 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1223 sysctl or by writing a value to
1224 /proc/sys/kernel/hung_task_timeout_secs.
1226 A timeout of 0 disables the check. The default is two minutes.
1227 Keeping the default should be fine in most cases.
1229 config BOOTPARAM_HUNG_TASK_PANIC
1230 bool "Panic (Reboot) On Hung Tasks"
1231 depends on DETECT_HUNG_TASK
1233 Say Y here to enable the kernel to panic on "hung tasks",
1234 which are bugs that cause the kernel to leave a task stuck
1235 in uninterruptible "D" state.
1237 The panic can be used in combination with panic_timeout,
1238 to cause the system to reboot automatically after a
1239 hung task has been detected. This feature is useful for
1240 high-availability systems that have uptime guarantees and
1241 where a hung tasks must be resolved ASAP.
1246 bool "Detect Workqueue Stalls"
1247 depends on DEBUG_KERNEL
1249 Say Y here to enable stall detection on workqueues. If a
1250 worker pool doesn't make forward progress on a pending work
1251 item for over a given amount of time, 30s by default, a
1252 warning message is printed along with dump of workqueue
1253 state. This can be configured through kernel parameter
1254 "workqueue.watchdog_thresh" and its sysfs counterpart.
1256 config WQ_CPU_INTENSIVE_REPORT
1257 bool "Report per-cpu work items which hog CPU for too long"
1258 depends on DEBUG_KERNEL
1260 Say Y here to enable reporting of concurrency-managed per-cpu work
1261 items that hog CPUs for longer than
1262 workqueue.cpu_intensive_thresh_us. Workqueue automatically
1263 detects and excludes them from concurrency management to prevent
1264 them from stalling other per-cpu work items. Occassional
1265 triggering may not necessarily indicate a problem. Repeated
1266 triggering likely indicates that the work item should be switched
1267 to use an unbound workqueue.
1270 tristate "Test module to generate lockups"
1273 This builds the "test_lockup" module that helps to make sure
1274 that watchdogs and lockup detectors are working properly.
1276 Depending on module parameters it could emulate soft or hard
1277 lockup, "hung task", or locking arbitrary lock for a long time.
1278 Also it could generate series of lockups with cooling-down periods.
1282 endmenu # "Debug lockups and hangs"
1284 menu "Scheduler Debugging"
1287 bool "Collect scheduler debugging info"
1288 depends on DEBUG_KERNEL && DEBUG_FS
1291 If you say Y here, the /sys/kernel/debug/sched file will be provided
1292 that can help debug the scheduler. The runtime overhead of this
1300 bool "Collect scheduler statistics"
1304 If you say Y here, additional code will be inserted into the
1305 scheduler and related routines to collect statistics about
1306 scheduler behavior and provide them in /proc/schedstat. These
1307 stats may be useful for both tuning and debugging the scheduler
1308 If you aren't debugging the scheduler or trying to tune a specific
1309 application, you can say N to avoid the very slight overhead
1314 config DEBUG_TIMEKEEPING
1315 bool "Enable extra timekeeping sanity checking"
1317 This option will enable additional timekeeping sanity checks
1318 which may be helpful when diagnosing issues where timekeeping
1319 problems are suspected.
1321 This may include checks in the timekeeping hotpaths, so this
1322 option may have a (very small) performance impact to some
1327 config DEBUG_PREEMPT
1328 bool "Debug preemptible kernel"
1329 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1331 If you say Y here then the kernel will use a debug variant of the
1332 commonly used smp_processor_id() function and will print warnings
1333 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1334 will detect preemption count underflows.
1336 This option has potential to introduce high runtime overhead,
1337 depending on workload as it triggers debugging routines for each
1338 this_cpu operation. It should only be used for debugging purposes.
1340 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1342 config LOCK_DEBUGGING_SUPPORT
1344 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1347 config PROVE_LOCKING
1348 bool "Lock debugging: prove locking correctness"
1349 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1351 select DEBUG_SPINLOCK
1352 select DEBUG_MUTEXES if !PREEMPT_RT
1353 select DEBUG_RT_MUTEXES if RT_MUTEXES
1354 select DEBUG_RWSEMS if !PREEMPT_RT
1355 select DEBUG_WW_MUTEX_SLOWPATH
1356 select DEBUG_LOCK_ALLOC
1357 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1358 select TRACE_IRQFLAGS
1361 This feature enables the kernel to prove that all locking
1362 that occurs in the kernel runtime is mathematically
1363 correct: that under no circumstance could an arbitrary (and
1364 not yet triggered) combination of observed locking
1365 sequences (on an arbitrary number of CPUs, running an
1366 arbitrary number of tasks and interrupt contexts) cause a
1369 In short, this feature enables the kernel to report locking
1370 related deadlocks before they actually occur.
1372 The proof does not depend on how hard and complex a
1373 deadlock scenario would be to trigger: how many
1374 participant CPUs, tasks and irq-contexts would be needed
1375 for it to trigger. The proof also does not depend on
1376 timing: if a race and a resulting deadlock is possible
1377 theoretically (no matter how unlikely the race scenario
1378 is), it will be proven so and will immediately be
1379 reported by the kernel (once the event is observed that
1380 makes the deadlock theoretically possible).
1382 If a deadlock is impossible (i.e. the locking rules, as
1383 observed by the kernel, are mathematically correct), the
1384 kernel reports nothing.
1386 NOTE: this feature can also be enabled for rwlocks, mutexes
1387 and rwsems - in which case all dependencies between these
1388 different locking variants are observed and mapped too, and
1389 the proof of observed correctness is also maintained for an
1390 arbitrary combination of these separate locking variants.
1392 For more details, see Documentation/locking/lockdep-design.rst.
1394 config PROVE_RAW_LOCK_NESTING
1395 bool "Enable raw_spinlock - spinlock nesting checks"
1396 depends on PROVE_LOCKING
1399 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1400 that the lock nesting rules for PREEMPT_RT enabled kernels are
1403 NOTE: There are known nesting problems. So if you enable this
1404 option expect lockdep splats until these problems have been fully
1405 addressed which is work in progress. This config switch allows to
1406 identify and analyze these problems. It will be removed and the
1407 check permanently enabled once the main issues have been fixed.
1409 If unsure, select N.
1412 bool "Lock usage statistics"
1413 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1415 select DEBUG_SPINLOCK
1416 select DEBUG_MUTEXES if !PREEMPT_RT
1417 select DEBUG_RT_MUTEXES if RT_MUTEXES
1418 select DEBUG_LOCK_ALLOC
1421 This feature enables tracking lock contention points
1423 For more details, see Documentation/locking/lockstat.rst
1425 This also enables lock events required by "perf lock",
1427 If you want to use "perf lock", you also need to turn on
1428 CONFIG_EVENT_TRACING.
1430 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1431 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1433 config DEBUG_RT_MUTEXES
1434 bool "RT Mutex debugging, deadlock detection"
1435 depends on DEBUG_KERNEL && RT_MUTEXES
1437 This allows rt mutex semantics violations and rt mutex related
1438 deadlocks (lockups) to be detected and reported automatically.
1440 config DEBUG_SPINLOCK
1441 bool "Spinlock and rw-lock debugging: basic checks"
1442 depends on DEBUG_KERNEL
1443 select UNINLINE_SPIN_UNLOCK
1445 Say Y here and build SMP to catch missing spinlock initialization
1446 and certain other kinds of spinlock errors commonly made. This is
1447 best used in conjunction with the NMI watchdog so that spinlock
1448 deadlocks are also debuggable.
1450 config DEBUG_MUTEXES
1451 bool "Mutex debugging: basic checks"
1452 depends on DEBUG_KERNEL && !PREEMPT_RT
1454 This feature allows mutex semantics violations to be detected and
1457 config DEBUG_WW_MUTEX_SLOWPATH
1458 bool "Wait/wound mutex debugging: Slowpath testing"
1459 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1460 select DEBUG_LOCK_ALLOC
1461 select DEBUG_SPINLOCK
1462 select DEBUG_MUTEXES if !PREEMPT_RT
1463 select DEBUG_RT_MUTEXES if PREEMPT_RT
1465 This feature enables slowpath testing for w/w mutex users by
1466 injecting additional -EDEADLK wound/backoff cases. Together with
1467 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1468 will test all possible w/w mutex interface abuse with the
1469 exception of simply not acquiring all the required locks.
1470 Note that this feature can introduce significant overhead, so
1471 it really should not be enabled in a production or distro kernel,
1472 even a debug kernel. If you are a driver writer, enable it. If
1473 you are a distro, do not.
1476 bool "RW Semaphore debugging: basic checks"
1477 depends on DEBUG_KERNEL && !PREEMPT_RT
1479 This debugging feature allows mismatched rw semaphore locks
1480 and unlocks to be detected and reported.
1482 config DEBUG_LOCK_ALLOC
1483 bool "Lock debugging: detect incorrect freeing of live locks"
1484 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1485 select DEBUG_SPINLOCK
1486 select DEBUG_MUTEXES if !PREEMPT_RT
1487 select DEBUG_RT_MUTEXES if RT_MUTEXES
1490 This feature will check whether any held lock (spinlock, rwlock,
1491 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1492 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1493 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1494 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1495 held during task exit.
1499 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1504 config LOCKDEP_SMALL
1508 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1509 depends on LOCKDEP && !LOCKDEP_SMALL
1513 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1515 config LOCKDEP_CHAINS_BITS
1516 int "Bitsize for MAX_LOCKDEP_CHAINS"
1517 depends on LOCKDEP && !LOCKDEP_SMALL
1521 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1523 config LOCKDEP_STACK_TRACE_BITS
1524 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1525 depends on LOCKDEP && !LOCKDEP_SMALL
1529 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1531 config LOCKDEP_STACK_TRACE_HASH_BITS
1532 int "Bitsize for STACK_TRACE_HASH_SIZE"
1533 depends on LOCKDEP && !LOCKDEP_SMALL
1537 Try increasing this value if you need large STACK_TRACE_HASH_SIZE.
1539 config LOCKDEP_CIRCULAR_QUEUE_BITS
1540 int "Bitsize for elements in circular_queue struct"
1545 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1547 config DEBUG_LOCKDEP
1548 bool "Lock dependency engine debugging"
1549 depends on DEBUG_KERNEL && LOCKDEP
1550 select DEBUG_IRQFLAGS
1552 If you say Y here, the lock dependency engine will do
1553 additional runtime checks to debug itself, at the price
1554 of more runtime overhead.
1556 config DEBUG_ATOMIC_SLEEP
1557 bool "Sleep inside atomic section checking"
1558 select PREEMPT_COUNT
1559 depends on DEBUG_KERNEL
1560 depends on !ARCH_NO_PREEMPT
1562 If you say Y here, various routines which may sleep will become very
1563 noisy if they are called inside atomic sections: when a spinlock is
1564 held, inside an rcu read side critical section, inside preempt disabled
1565 sections, inside an interrupt, etc...
1567 config DEBUG_LOCKING_API_SELFTESTS
1568 bool "Locking API boot-time self-tests"
1569 depends on DEBUG_KERNEL
1571 Say Y here if you want the kernel to run a short self-test during
1572 bootup. The self-test checks whether common types of locking bugs
1573 are detected by debugging mechanisms or not. (if you disable
1574 lock debugging then those bugs won't be detected of course.)
1575 The following locking APIs are covered: spinlocks, rwlocks,
1578 config LOCK_TORTURE_TEST
1579 tristate "torture tests for locking"
1580 depends on DEBUG_KERNEL
1583 This option provides a kernel module that runs torture tests
1584 on kernel locking primitives. The kernel module may be built
1585 after the fact on the running kernel to be tested, if desired.
1587 Say Y here if you want kernel locking-primitive torture tests
1588 to be built into the kernel.
1589 Say M if you want these torture tests to build as a module.
1590 Say N if you are unsure.
1592 config WW_MUTEX_SELFTEST
1593 tristate "Wait/wound mutex selftests"
1595 This option provides a kernel module that runs tests on the
1596 on the struct ww_mutex locking API.
1598 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1599 with this test harness.
1601 Say M if you want these self tests to build as a module.
1602 Say N if you are unsure.
1604 config SCF_TORTURE_TEST
1605 tristate "torture tests for smp_call_function*()"
1606 depends on DEBUG_KERNEL
1609 This option provides a kernel module that runs torture tests
1610 on the smp_call_function() family of primitives. The kernel
1611 module may be built after the fact on the running kernel to
1612 be tested, if desired.
1614 config CSD_LOCK_WAIT_DEBUG
1615 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1616 depends on DEBUG_KERNEL
1620 This option enables debug prints when CPUs are slow to respond
1621 to the smp_call_function*() IPI wrappers. These debug prints
1622 include the IPI handler function currently executing (if any)
1623 and relevant stack traces.
1625 config CSD_LOCK_WAIT_DEBUG_DEFAULT
1626 bool "Default csd_lock_wait() debugging on at boot time"
1627 depends on CSD_LOCK_WAIT_DEBUG
1631 This option causes the csdlock_debug= kernel boot parameter to
1632 default to 1 (basic debugging) instead of 0 (no debugging).
1634 endmenu # lock debugging
1636 config TRACE_IRQFLAGS
1637 depends on TRACE_IRQFLAGS_SUPPORT
1640 Enables hooks to interrupt enabling and disabling for
1641 either tracing or lock debugging.
1643 config TRACE_IRQFLAGS_NMI
1645 depends on TRACE_IRQFLAGS
1646 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1648 config NMI_CHECK_CPU
1649 bool "Debugging for CPUs failing to respond to backtrace requests"
1650 depends on DEBUG_KERNEL
1654 Enables debug prints when a CPU fails to respond to a given
1655 backtrace NMI. These prints provide some reasons why a CPU
1656 might legitimately be failing to respond, for example, if it
1657 is offline of if ignore_nmis is set.
1659 config DEBUG_IRQFLAGS
1660 bool "Debug IRQ flag manipulation"
1662 Enables checks for potentially unsafe enabling or disabling of
1663 interrupts, such as calling raw_local_irq_restore() when interrupts
1667 bool "Stack backtrace support"
1668 depends on STACKTRACE_SUPPORT
1670 This option causes the kernel to create a /proc/pid/stack for
1671 every process, showing its current stack trace.
1672 It is also used by various kernel debugging features that require
1673 stack trace generation.
1675 config WARN_ALL_UNSEEDED_RANDOM
1676 bool "Warn for all uses of unseeded randomness"
1679 Some parts of the kernel contain bugs relating to their use of
1680 cryptographically secure random numbers before it's actually possible
1681 to generate those numbers securely. This setting ensures that these
1682 flaws don't go unnoticed, by enabling a message, should this ever
1683 occur. This will allow people with obscure setups to know when things
1684 are going wrong, so that they might contact developers about fixing
1687 Unfortunately, on some models of some architectures getting
1688 a fully seeded CRNG is extremely difficult, and so this can
1689 result in dmesg getting spammed for a surprisingly long
1690 time. This is really bad from a security perspective, and
1691 so architecture maintainers really need to do what they can
1692 to get the CRNG seeded sooner after the system is booted.
1693 However, since users cannot do anything actionable to
1694 address this, by default this option is disabled.
1696 Say Y here if you want to receive warnings for all uses of
1697 unseeded randomness. This will be of use primarily for
1698 those developers interested in improving the security of
1699 Linux kernels running on their architecture (or
1702 config DEBUG_KOBJECT
1703 bool "kobject debugging"
1704 depends on DEBUG_KERNEL
1706 If you say Y here, some extra kobject debugging messages will be sent
1709 config DEBUG_KOBJECT_RELEASE
1710 bool "kobject release debugging"
1711 depends on DEBUG_OBJECTS_TIMERS
1713 kobjects are reference counted objects. This means that their
1714 last reference count put is not predictable, and the kobject can
1715 live on past the point at which a driver decides to drop its
1716 initial reference to the kobject gained on allocation. An
1717 example of this would be a struct device which has just been
1720 However, some buggy drivers assume that after such an operation,
1721 the memory backing the kobject can be immediately freed. This
1722 goes completely against the principles of a refcounted object.
1724 If you say Y here, the kernel will delay the release of kobjects
1725 on the last reference count to improve the visibility of this
1726 kind of kobject release bug.
1728 config HAVE_DEBUG_BUGVERBOSE
1731 menu "Debug kernel data structures"
1734 bool "Debug linked list manipulation"
1735 depends on DEBUG_KERNEL
1736 select LIST_HARDENED
1738 Enable this to turn on extended checks in the linked-list walking
1741 This option trades better quality error reports for performance, and
1742 is more suitable for kernel debugging. If you care about performance,
1743 you should only enable CONFIG_LIST_HARDENED instead.
1748 bool "Debug priority linked list manipulation"
1749 depends on DEBUG_KERNEL
1751 Enable this to turn on extended checks in the priority-ordered
1752 linked-list (plist) walking routines. This checks the entire
1753 list multiple times during each manipulation.
1758 bool "Debug SG table operations"
1759 depends on DEBUG_KERNEL
1761 Enable this to turn on checks on scatter-gather tables. This can
1762 help find problems with drivers that do not properly initialize
1767 config DEBUG_NOTIFIERS
1768 bool "Debug notifier call chains"
1769 depends on DEBUG_KERNEL
1771 Enable this to turn on sanity checking for notifier call chains.
1772 This is most useful for kernel developers to make sure that
1773 modules properly unregister themselves from notifier chains.
1774 This is a relatively cheap check but if you care about maximum
1777 config DEBUG_CLOSURES
1778 bool "Debug closures (bcache async widgits)"
1782 Keeps all active closures in a linked list and provides a debugfs
1783 interface to list them, which makes it possible to see asynchronous
1784 operations that get stuck.
1786 config DEBUG_MAPLE_TREE
1787 bool "Debug maple trees"
1788 depends on DEBUG_KERNEL
1790 Enable maple tree debugging information and extra validations.
1796 source "kernel/rcu/Kconfig.debug"
1798 config DEBUG_WQ_FORCE_RR_CPU
1799 bool "Force round-robin CPU selection for unbound work items"
1800 depends on DEBUG_KERNEL
1803 Workqueue used to implicitly guarantee that work items queued
1804 without explicit CPU specified are put on the local CPU. This
1805 guarantee is no longer true and while local CPU is still
1806 preferred work items may be put on foreign CPUs. Kernel
1807 parameter "workqueue.debug_force_rr_cpu" is added to force
1808 round-robin CPU selection to flush out usages which depend on the
1809 now broken guarantee. This config option enables the debug
1810 feature by default. When enabled, memory and cache locality will
1813 config CPU_HOTPLUG_STATE_CONTROL
1814 bool "Enable CPU hotplug state control"
1815 depends on DEBUG_KERNEL
1816 depends on HOTPLUG_CPU
1819 Allows to write steps between "offline" and "online" to the CPUs
1820 sysfs target file so states can be stepped granular. This is a debug
1821 option for now as the hotplug machinery cannot be stopped and
1822 restarted at arbitrary points yet.
1824 Say N if your are unsure.
1827 bool "Latency measuring infrastructure"
1828 depends on DEBUG_KERNEL
1829 depends on STACKTRACE_SUPPORT
1831 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1837 Enable this option if you want to use the LatencyTOP tool
1838 to find out which userspace is blocking on what kernel operations.
1840 config DEBUG_CGROUP_REF
1841 bool "Disable inlining of cgroup css reference count functions"
1842 depends on DEBUG_KERNEL
1847 Force cgroup css reference count functions to not be inlined so
1848 that they can be kprobed for debugging.
1850 source "kernel/trace/Kconfig"
1852 config PROVIDE_OHCI1394_DMA_INIT
1853 bool "Remote debugging over FireWire early on boot"
1854 depends on PCI && X86
1856 If you want to debug problems which hang or crash the kernel early
1857 on boot and the crashing machine has a FireWire port, you can use
1858 this feature to remotely access the memory of the crashed machine
1859 over FireWire. This employs remote DMA as part of the OHCI1394
1860 specification which is now the standard for FireWire controllers.
1862 With remote DMA, you can monitor the printk buffer remotely using
1863 firescope and access all memory below 4GB using fireproxy from gdb.
1864 Even controlling a kernel debugger is possible using remote DMA.
1868 If ohci1394_dma=early is used as boot parameter, it will initialize
1869 all OHCI1394 controllers which are found in the PCI config space.
1871 As all changes to the FireWire bus such as enabling and disabling
1872 devices cause a bus reset and thereby disable remote DMA for all
1873 devices, be sure to have the cable plugged and FireWire enabled on
1874 the debugging host before booting the debug target for debugging.
1876 This code (~1k) is freed after boot. By then, the firewire stack
1877 in charge of the OHCI-1394 controllers should be used instead.
1879 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1881 source "samples/Kconfig"
1883 config ARCH_HAS_DEVMEM_IS_ALLOWED
1886 config STRICT_DEVMEM
1887 bool "Filter access to /dev/mem"
1888 depends on MMU && DEVMEM
1889 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1890 default y if PPC || X86 || ARM64
1892 If this option is disabled, you allow userspace (root) access to all
1893 of memory, including kernel and userspace memory. Accidental
1894 access to this is obviously disastrous, but specific access can
1895 be used by people debugging the kernel. Note that with PAT support
1896 enabled, even in this case there are restrictions on /dev/mem
1897 use due to the cache aliasing requirements.
1899 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1900 file only allows userspace access to PCI space and the BIOS code and
1901 data regions. This is sufficient for dosemu and X and all common
1906 config IO_STRICT_DEVMEM
1907 bool "Filter I/O access to /dev/mem"
1908 depends on STRICT_DEVMEM
1910 If this option is disabled, you allow userspace (root) access to all
1911 io-memory regardless of whether a driver is actively using that
1912 range. Accidental access to this is obviously disastrous, but
1913 specific access can be used by people debugging kernel drivers.
1915 If this option is switched on, the /dev/mem file only allows
1916 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1917 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1918 if the driver using a given range cannot be disabled.
1922 menu "$(SRCARCH) Debugging"
1924 source "arch/$(SRCARCH)/Kconfig.debug"
1928 menu "Kernel Testing and Coverage"
1930 source "lib/kunit/Kconfig"
1932 config NOTIFIER_ERROR_INJECTION
1933 tristate "Notifier error injection"
1934 depends on DEBUG_KERNEL
1937 This option provides the ability to inject artificial errors to
1938 specified notifier chain callbacks. It is useful to test the error
1939 handling of notifier call chain failures.
1943 config PM_NOTIFIER_ERROR_INJECT
1944 tristate "PM notifier error injection module"
1945 depends on PM && NOTIFIER_ERROR_INJECTION
1946 default m if PM_DEBUG
1948 This option provides the ability to inject artificial errors to
1949 PM notifier chain callbacks. It is controlled through debugfs
1950 interface /sys/kernel/debug/notifier-error-inject/pm
1952 If the notifier call chain should be failed with some events
1953 notified, write the error code to "actions/<notifier event>/error".
1955 Example: Inject PM suspend error (-12 = -ENOMEM)
1957 # cd /sys/kernel/debug/notifier-error-inject/pm/
1958 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1959 # echo mem > /sys/power/state
1960 bash: echo: write error: Cannot allocate memory
1962 To compile this code as a module, choose M here: the module will
1963 be called pm-notifier-error-inject.
1967 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1968 tristate "OF reconfig notifier error injection module"
1969 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1971 This option provides the ability to inject artificial errors to
1972 OF reconfig notifier chain callbacks. It is controlled
1973 through debugfs interface under
1974 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1976 If the notifier call chain should be failed with some events
1977 notified, write the error code to "actions/<notifier event>/error".
1979 To compile this code as a module, choose M here: the module will
1980 be called of-reconfig-notifier-error-inject.
1984 config NETDEV_NOTIFIER_ERROR_INJECT
1985 tristate "Netdev notifier error injection module"
1986 depends on NET && NOTIFIER_ERROR_INJECTION
1988 This option provides the ability to inject artificial errors to
1989 netdevice notifier chain callbacks. It is controlled through debugfs
1990 interface /sys/kernel/debug/notifier-error-inject/netdev
1992 If the notifier call chain should be failed with some events
1993 notified, write the error code to "actions/<notifier event>/error".
1995 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1997 # cd /sys/kernel/debug/notifier-error-inject/netdev
1998 # echo -22 > actions/NETDEV_CHANGEMTU/error
1999 # ip link set eth0 mtu 1024
2000 RTNETLINK answers: Invalid argument
2002 To compile this code as a module, choose M here: the module will
2003 be called netdev-notifier-error-inject.
2007 config FUNCTION_ERROR_INJECTION
2008 bool "Fault-injections of functions"
2009 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
2011 Add fault injections into various functions that are annotated with
2012 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
2013 value of these functions. This is useful to test error paths of code.
2017 config FAULT_INJECTION
2018 bool "Fault-injection framework"
2019 depends on DEBUG_KERNEL
2021 Provide fault-injection framework.
2022 For more details, see Documentation/fault-injection/.
2025 bool "Fault-injection capability for kmalloc"
2026 depends on FAULT_INJECTION
2028 Provide fault-injection capability for kmalloc.
2030 config FAIL_PAGE_ALLOC
2031 bool "Fault-injection capability for alloc_pages()"
2032 depends on FAULT_INJECTION
2034 Provide fault-injection capability for alloc_pages().
2036 config FAULT_INJECTION_USERCOPY
2037 bool "Fault injection capability for usercopy functions"
2038 depends on FAULT_INJECTION
2040 Provides fault-injection capability to inject failures
2041 in usercopy functions (copy_from_user(), get_user(), ...).
2043 config FAIL_MAKE_REQUEST
2044 bool "Fault-injection capability for disk IO"
2045 depends on FAULT_INJECTION && BLOCK
2047 Provide fault-injection capability for disk IO.
2049 config FAIL_IO_TIMEOUT
2050 bool "Fault-injection capability for faking disk interrupts"
2051 depends on FAULT_INJECTION && BLOCK
2053 Provide fault-injection capability on end IO handling. This
2054 will make the block layer "forget" an interrupt as configured,
2055 thus exercising the error handling.
2057 Only works with drivers that use the generic timeout handling,
2058 for others it won't do anything.
2061 bool "Fault-injection capability for futexes"
2063 depends on FAULT_INJECTION && FUTEX
2065 Provide fault-injection capability for futexes.
2067 config FAULT_INJECTION_DEBUG_FS
2068 bool "Debugfs entries for fault-injection capabilities"
2069 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
2071 Enable configuration of fault-injection capabilities via debugfs.
2073 config FAIL_FUNCTION
2074 bool "Fault-injection capability for functions"
2075 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
2077 Provide function-based fault-injection capability.
2078 This will allow you to override a specific function with a return
2079 with given return value. As a result, function caller will see
2080 an error value and have to handle it. This is useful to test the
2081 error handling in various subsystems.
2083 config FAIL_MMC_REQUEST
2084 bool "Fault-injection capability for MMC IO"
2085 depends on FAULT_INJECTION_DEBUG_FS && MMC
2087 Provide fault-injection capability for MMC IO.
2088 This will make the mmc core return data errors. This is
2089 useful to test the error handling in the mmc block device
2090 and to test how the mmc host driver handles retries from
2094 bool "Fault-injection capability for SunRPC"
2095 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
2097 Provide fault-injection capability for SunRPC and
2100 config FAULT_INJECTION_CONFIGFS
2101 bool "Configfs interface for fault-injection capabilities"
2102 depends on FAULT_INJECTION
2105 This option allows configfs-based drivers to dynamically configure
2106 fault-injection via configfs. Each parameter for driver-specific
2107 fault-injection can be made visible as a configfs attribute in a
2111 config FAULT_INJECTION_STACKTRACE_FILTER
2112 bool "stacktrace filter for fault-injection capabilities"
2113 depends on FAULT_INJECTION
2114 depends on (FAULT_INJECTION_DEBUG_FS || FAULT_INJECTION_CONFIGFS) && STACKTRACE_SUPPORT
2116 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
2118 Provide stacktrace filter for fault-injection capabilities
2120 config ARCH_HAS_KCOV
2123 An architecture should select this when it can successfully
2124 build and run with CONFIG_KCOV. This typically requires
2125 disabling instrumentation for some early boot code.
2127 config CC_HAS_SANCOV_TRACE_PC
2128 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
2132 bool "Code coverage for fuzzing"
2133 depends on ARCH_HAS_KCOV
2134 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
2135 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
2136 GCC_VERSION >= 120000 || CC_IS_CLANG
2138 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
2139 select OBJTOOL if HAVE_NOINSTR_HACK
2141 KCOV exposes kernel code coverage information in a form suitable
2142 for coverage-guided fuzzing (randomized testing).
2144 For more details, see Documentation/dev-tools/kcov.rst.
2146 config KCOV_ENABLE_COMPARISONS
2147 bool "Enable comparison operands collection by KCOV"
2149 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2151 KCOV also exposes operands of every comparison in the instrumented
2152 code along with operand sizes and PCs of the comparison instructions.
2153 These operands can be used by fuzzing engines to improve the quality
2154 of fuzzing coverage.
2156 config KCOV_INSTRUMENT_ALL
2157 bool "Instrument all code by default"
2161 If you are doing generic system call fuzzing (like e.g. syzkaller),
2162 then you will want to instrument the whole kernel and you should
2163 say y here. If you are doing more targeted fuzzing (like e.g.
2164 filesystem fuzzing with AFL) then you will want to enable coverage
2165 for more specific subsets of files, and should say n here.
2167 config KCOV_IRQ_AREA_SIZE
2168 hex "Size of interrupt coverage collection area in words"
2172 KCOV uses preallocated per-cpu areas to collect coverage from
2173 soft interrupts. This specifies the size of those areas in the
2174 number of unsigned long words.
2176 menuconfig RUNTIME_TESTING_MENU
2177 bool "Runtime Testing"
2180 if RUNTIME_TESTING_MENU
2183 tristate "Dhrystone benchmark test"
2185 Enable this to include the Dhrystone 2.1 benchmark. This test
2186 calculates the number of Dhrystones per second, and the number of
2187 DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided
2188 by 1757 (the number of Dhrystones per second obtained on the VAX
2189 11/780, nominally a 1 MIPS machine).
2191 To run the benchmark, it needs to be enabled explicitly, either from
2192 the kernel command line (when built-in), or from userspace (when
2193 built-in or modular).
2195 Run once during kernel boot:
2199 Set number of iterations from kernel command line:
2201 test_dhry.iterations=<n>
2203 Set number of iterations from userspace:
2205 echo <n> > /sys/module/test_dhry/parameters/iterations
2207 Trigger manual run from userspace:
2209 echo y > /sys/module/test_dhry/parameters/run
2211 If the number of iterations is <= 0, the test will devise a suitable
2212 number of iterations (test runs for at least 2s) automatically.
2213 This process takes ca. 4s.
2218 tristate "Linux Kernel Dump Test Tool Module"
2221 This module enables testing of the different dumping mechanisms by
2222 inducing system failures at predefined crash points.
2223 If you don't need it: say N
2224 Choose M here to compile this code as a module. The module will be
2227 Documentation on how to use the module can be found in
2228 Documentation/fault-injection/provoke-crashes.rst
2230 config CPUMASK_KUNIT_TEST
2231 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2233 default KUNIT_ALL_TESTS
2235 Enable to turn on cpumask tests, running at boot or module load time.
2237 For more information on KUnit and unit tests in general, please refer
2238 to the KUnit documentation in Documentation/dev-tools/kunit/.
2242 config TEST_LIST_SORT
2243 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2245 default KUNIT_ALL_TESTS
2247 Enable this to turn on 'list_sort()' function test. This test is
2248 executed only once during system boot (so affects only boot time),
2249 or at module load time.
2253 config TEST_MIN_HEAP
2254 tristate "Min heap test"
2255 depends on DEBUG_KERNEL || m
2257 Enable this to turn on min heap function tests. This test is
2258 executed only once during system boot (so affects only boot time),
2259 or at module load time.
2264 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2266 default KUNIT_ALL_TESTS
2268 This option enables the self-test function of 'sort()' at boot,
2269 or at module load time.
2274 tristate "64bit/32bit division and modulo test"
2275 depends on DEBUG_KERNEL || m
2277 Enable this to turn on 'do_div()' function test. This test is
2278 executed only once during system boot (so affects only boot time),
2279 or at module load time.
2283 config TEST_IOV_ITER
2284 tristate "Test iov_iter operation" if !KUNIT_ALL_TESTS
2287 default KUNIT_ALL_TESTS
2289 Enable this to turn on testing of the operation of the I/O iterator
2290 (iov_iter). This test is executed only once during system boot (so
2291 affects only boot time), or at module load time.
2295 config KPROBES_SANITY_TEST
2296 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2297 depends on DEBUG_KERNEL
2300 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
2301 default KUNIT_ALL_TESTS
2303 This option provides for testing basic kprobes functionality on
2304 boot. Samples of kprobe and kretprobe are inserted and
2305 verified for functionality.
2307 Say N if you are unsure.
2309 config FPROBE_SANITY_TEST
2310 bool "Self test for fprobe"
2311 depends on DEBUG_KERNEL
2315 This option will enable testing the fprobe when the system boot.
2316 A series of tests are made to verify that the fprobe is functioning
2319 Say N if you are unsure.
2321 config BACKTRACE_SELF_TEST
2322 tristate "Self test for the backtrace code"
2323 depends on DEBUG_KERNEL
2325 This option provides a kernel module that can be used to test
2326 the kernel stack backtrace code. This option is not useful
2327 for distributions or general kernels, but only for kernel
2328 developers working on architecture code.
2330 Note that if you want to also test saved backtraces, you will
2331 have to enable STACKTRACE as well.
2333 Say N if you are unsure.
2335 config TEST_REF_TRACKER
2336 tristate "Self test for reference tracker"
2337 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2340 This option provides a kernel module performing tests
2341 using reference tracker infrastructure.
2343 Say N if you are unsure.
2346 tristate "Red-Black tree test"
2347 depends on DEBUG_KERNEL
2349 A benchmark measuring the performance of the rbtree library.
2350 Also includes rbtree invariant checks.
2352 config REED_SOLOMON_TEST
2353 tristate "Reed-Solomon library test"
2354 depends on DEBUG_KERNEL || m
2356 select REED_SOLOMON_ENC16
2357 select REED_SOLOMON_DEC16
2359 This option enables the self-test function of rslib at boot,
2360 or at module load time.
2364 config INTERVAL_TREE_TEST
2365 tristate "Interval tree test"
2366 depends on DEBUG_KERNEL
2367 select INTERVAL_TREE
2369 A benchmark measuring the performance of the interval tree library
2372 tristate "Per cpu operations test"
2373 depends on m && DEBUG_KERNEL
2375 Enable this option to build test module which validates per-cpu
2380 config ATOMIC64_SELFTEST
2381 tristate "Perform an atomic64_t self-test"
2383 Enable this option to test the atomic64_t functions at boot or
2384 at module load time.
2388 config ASYNC_RAID6_TEST
2389 tristate "Self test for hardware accelerated raid6 recovery"
2390 depends on ASYNC_RAID6_RECOV
2393 This is a one-shot self test that permutes through the
2394 recovery of all the possible two disk failure scenarios for a
2395 N-disk array. Recovery is performed with the asynchronous
2396 raid6 recovery routines, and will optionally use an offload
2397 engine if one is available.
2402 tristate "Test functions located in the hexdump module at runtime"
2404 config STRING_KUNIT_TEST
2405 tristate "KUnit test string functions at runtime" if !KUNIT_ALL_TESTS
2407 default KUNIT_ALL_TESTS
2409 config STRING_HELPERS_KUNIT_TEST
2410 tristate "KUnit test string helpers at runtime" if !KUNIT_ALL_TESTS
2412 default KUNIT_ALL_TESTS
2415 tristate "Test kstrto*() family of functions at runtime"
2418 tristate "Test printf() family of functions at runtime"
2421 tristate "Test scanf() family of functions at runtime"
2424 tristate "Test bitmap_*() family of functions at runtime"
2426 Enable this option to test the bitmap functions at boot.
2431 tristate "Test functions located in the uuid module at runtime"
2434 tristate "Test the XArray code at runtime"
2436 config TEST_MAPLE_TREE
2437 tristate "Test the Maple Tree code at runtime or module load"
2439 Enable this option to test the maple tree code functions at boot, or
2440 when the module is loaded. Enable "Debug Maple Trees" will enable
2441 more verbose output on failures.
2445 config TEST_RHASHTABLE
2446 tristate "Perform selftest on resizable hash table"
2448 Enable this option to test the rhashtable functions at boot.
2453 tristate "Perform selftest on IDA functions"
2456 tristate "Perform selftest on priority array manager"
2459 Enable this option to test priority array manager on boot
2464 config TEST_IRQ_TIMINGS
2465 bool "IRQ timings selftest"
2466 depends on IRQ_TIMINGS
2468 Enable this option to test the irq timings code on boot.
2473 tristate "Test module loading with 'hello world' module"
2476 This builds the "test_module" module that emits "Hello, world"
2477 on printk when loaded. It is designed to be used for basic
2478 evaluation of the module loading subsystem (for example when
2479 validating module verification). It lacks any extra dependencies,
2480 and will not normally be loaded by the system unless explicitly
2486 tristate "Test module for compilation of bitops operations"
2488 This builds the "test_bitops" module that is much like the
2489 TEST_LKM module except that it does a basic exercise of the
2490 set/clear_bit macros and get_count_order/long to make sure there are
2491 no compiler warnings from C=1 sparse checker or -Wextra
2492 compilations. It has no dependencies and doesn't run or load unless
2493 explicitly requested by name. for example: modprobe test_bitops.
2498 tristate "Test module for stress/performance analysis of vmalloc allocator"
2503 This builds the "test_vmalloc" module that should be used for
2504 stress and performance analysis. So, any new change for vmalloc
2505 subsystem can be evaluated from performance and stability point
2511 tristate "Test BPF filter functionality"
2514 This builds the "test_bpf" module that runs various test vectors
2515 against the BPF interpreter or BPF JIT compiler depending on the
2516 current setting. This is in particular useful for BPF JIT compiler
2517 development, but also to run regression tests against changes in
2518 the interpreter code. It also enables test stubs for eBPF maps and
2519 verifier used by user space verifier testsuite.
2523 config TEST_BLACKHOLE_DEV
2524 tristate "Test blackhole netdev functionality"
2527 This builds the "test_blackhole_dev" module that validates the
2528 data path through this blackhole netdev.
2532 config FIND_BIT_BENCHMARK
2533 tristate "Test find_bit functions"
2535 This builds the "test_find_bit" module that measure find_*_bit()
2536 functions performance.
2540 config TEST_FIRMWARE
2541 tristate "Test firmware loading via userspace interface"
2542 depends on FW_LOADER
2544 This builds the "test_firmware" module that creates a userspace
2545 interface for testing firmware loading. This can be used to
2546 control the triggering of firmware loading without needing an
2547 actual firmware-using device. The contents can be rechecked by
2553 tristate "sysctl test driver"
2554 depends on PROC_SYSCTL
2556 This builds the "test_sysctl" module. This driver enables to test the
2557 proc sysctl interfaces available to drivers safely without affecting
2558 production knobs which might alter system functionality.
2562 config BITFIELD_KUNIT
2563 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2565 default KUNIT_ALL_TESTS
2567 Enable this option to test the bitfield functions at boot.
2569 KUnit tests run during boot and output the results to the debug log
2570 in TAP format (http://testanything.org/). Only useful for kernel devs
2571 running the KUnit test harness, and not intended for inclusion into a
2574 For more information on KUnit and unit tests in general please refer
2575 to the KUnit documentation in Documentation/dev-tools/kunit/.
2579 config CHECKSUM_KUNIT
2580 tristate "KUnit test checksum functions at runtime" if !KUNIT_ALL_TESTS
2582 default KUNIT_ALL_TESTS
2584 Enable this option to test the checksum functions at boot.
2586 KUnit tests run during boot and output the results to the debug log
2587 in TAP format (http://testanything.org/). Only useful for kernel devs
2588 running the KUnit test harness, and not intended for inclusion into a
2591 For more information on KUnit and unit tests in general please refer
2592 to the KUnit documentation in Documentation/dev-tools/kunit/.
2596 config HASH_KUNIT_TEST
2597 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2599 default KUNIT_ALL_TESTS
2601 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2602 integer (<linux/hash.h>) hash functions on boot.
2604 KUnit tests run during boot and output the results to the debug log
2605 in TAP format (https://testanything.org/). Only useful for kernel devs
2606 running the KUnit test harness, and not intended for inclusion into a
2609 For more information on KUnit and unit tests in general please refer
2610 to the KUnit documentation in Documentation/dev-tools/kunit/.
2612 This is intended to help people writing architecture-specific
2613 optimized versions. If unsure, say N.
2615 config RESOURCE_KUNIT_TEST
2616 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2618 default KUNIT_ALL_TESTS
2620 This builds the resource API unit test.
2621 Tests the logic of API provided by resource.c and ioport.h.
2622 For more information on KUnit and unit tests in general please refer
2623 to the KUnit documentation in Documentation/dev-tools/kunit/.
2627 config SYSCTL_KUNIT_TEST
2628 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2630 default KUNIT_ALL_TESTS
2632 This builds the proc sysctl unit test, which runs on boot.
2633 Tests the API contract and implementation correctness of sysctl.
2634 For more information on KUnit and unit tests in general please refer
2635 to the KUnit documentation in Documentation/dev-tools/kunit/.
2639 config LIST_KUNIT_TEST
2640 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2642 default KUNIT_ALL_TESTS
2644 This builds the linked list KUnit test suite.
2645 It tests that the API and basic functionality of the list_head type
2646 and associated macros.
2648 KUnit tests run during boot and output the results to the debug log
2649 in TAP format (https://testanything.org/). Only useful for kernel devs
2650 running the KUnit test harness, and not intended for inclusion into a
2653 For more information on KUnit and unit tests in general please refer
2654 to the KUnit documentation in Documentation/dev-tools/kunit/.
2658 config HASHTABLE_KUNIT_TEST
2659 tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS
2661 default KUNIT_ALL_TESTS
2663 This builds the hashtable KUnit test suite.
2664 It tests the basic functionality of the API defined in
2665 include/linux/hashtable.h. For more information on KUnit and
2666 unit tests in general please refer to the KUnit documentation
2667 in Documentation/dev-tools/kunit/.
2671 config LINEAR_RANGES_TEST
2672 tristate "KUnit test for linear_ranges"
2674 select LINEAR_RANGES
2676 This builds the linear_ranges unit test, which runs on boot.
2677 Tests the linear_ranges logic correctness.
2678 For more information on KUnit and unit tests in general please refer
2679 to the KUnit documentation in Documentation/dev-tools/kunit/.
2683 config CMDLINE_KUNIT_TEST
2684 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2686 default KUNIT_ALL_TESTS
2688 This builds the cmdline API unit test.
2689 Tests the logic of API provided by cmdline.c.
2690 For more information on KUnit and unit tests in general please refer
2691 to the KUnit documentation in Documentation/dev-tools/kunit/.
2696 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2698 default KUNIT_ALL_TESTS
2700 This builds the bits unit test.
2701 Tests the logic of macros defined in bits.h.
2702 For more information on KUnit and unit tests in general please refer
2703 to the KUnit documentation in Documentation/dev-tools/kunit/.
2707 config SLUB_KUNIT_TEST
2708 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2709 depends on SLUB_DEBUG && KUNIT
2710 default KUNIT_ALL_TESTS
2712 This builds SLUB allocator unit test.
2713 Tests SLUB cache debugging functionality.
2714 For more information on KUnit and unit tests in general please refer
2715 to the KUnit documentation in Documentation/dev-tools/kunit/.
2719 config RATIONAL_KUNIT_TEST
2720 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2721 depends on KUNIT && RATIONAL
2722 default KUNIT_ALL_TESTS
2724 This builds the rational math unit test.
2725 For more information on KUnit and unit tests in general please refer
2726 to the KUnit documentation in Documentation/dev-tools/kunit/.
2730 config MEMCPY_KUNIT_TEST
2731 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2733 default KUNIT_ALL_TESTS
2735 Builds unit tests for memcpy(), memmove(), and memset() functions.
2736 For more information on KUnit and unit tests in general please refer
2737 to the KUnit documentation in Documentation/dev-tools/kunit/.
2741 config IS_SIGNED_TYPE_KUNIT_TEST
2742 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS
2744 default KUNIT_ALL_TESTS
2746 Builds unit tests for the is_signed_type() macro.
2748 For more information on KUnit and unit tests in general please refer
2749 to the KUnit documentation in Documentation/dev-tools/kunit/.
2753 config OVERFLOW_KUNIT_TEST
2754 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2756 default KUNIT_ALL_TESTS
2758 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2761 For more information on KUnit and unit tests in general please refer
2762 to the KUnit documentation in Documentation/dev-tools/kunit/.
2766 config STACKINIT_KUNIT_TEST
2767 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2769 default KUNIT_ALL_TESTS
2771 Test if the kernel is zero-initializing stack variables and
2772 padding. Coverage is controlled by compiler flags,
2773 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2774 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2775 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2777 config FORTIFY_KUNIT_TEST
2778 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS
2780 default KUNIT_ALL_TESTS
2782 Builds unit tests for checking internals of FORTIFY_SOURCE as used
2783 by the str*() and mem*() family of functions. For testing runtime
2784 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests.
2786 config HW_BREAKPOINT_KUNIT_TEST
2787 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS
2788 depends on HAVE_HW_BREAKPOINT
2790 default KUNIT_ALL_TESTS
2792 Tests for hw_breakpoint constraints accounting.
2796 config SIPHASH_KUNIT_TEST
2797 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS
2799 default KUNIT_ALL_TESTS
2801 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2802 functions on boot (or module load).
2804 This is intended to help people writing architecture-specific
2805 optimized versions. If unsure, say N.
2807 config USERCOPY_KUNIT_TEST
2808 tristate "KUnit Test for user/kernel boundary protections"
2810 default KUNIT_ALL_TESTS
2812 This builds the "usercopy_kunit" module that runs sanity checks
2813 on the copy_to/from_user infrastructure, making sure basic
2814 user/kernel boundary testing is working.
2817 tristate "udelay test driver"
2819 This builds the "udelay_test" module that helps to make sure
2820 that udelay() is working properly.
2824 config TEST_STATIC_KEYS
2825 tristate "Test static keys"
2828 Test the static key interfaces.
2832 config TEST_DYNAMIC_DEBUG
2833 tristate "Test DYNAMIC_DEBUG"
2834 depends on DYNAMIC_DEBUG
2836 This module registers a tracer callback to count enabled
2837 pr_debugs in a 'do_debugging' function, then alters their
2838 enablements, calls the function, and compares counts.
2843 tristate "kmod stress tester"
2845 depends on NETDEVICES && NET_CORE && INET # for TUN
2847 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2853 Test the kernel's module loading mechanism: kmod. kmod implements
2854 support to load modules using the Linux kernel's usermode helper.
2855 This test provides a series of tests against kmod.
2857 Although technically you can either build test_kmod as a module or
2858 into the kernel we disallow building it into the kernel since
2859 it stress tests request_module() and this will very likely cause
2860 some issues by taking over precious threads available from other
2861 module load requests, ultimately this could be fatal.
2865 tools/testing/selftests/kmod/kmod.sh --help
2869 config TEST_DEBUG_VIRTUAL
2870 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2871 depends on DEBUG_VIRTUAL
2873 Test the kernel's ability to detect incorrect calls to
2874 virt_to_phys() done against the non-linear part of the
2875 kernel's virtual address map.
2879 config TEST_MEMCAT_P
2880 tristate "Test memcat_p() helper function"
2882 Test the memcat_p() helper for correctly merging two
2883 pointer arrays together.
2888 tristate "Perform selftest on object aggreration manager"
2892 Enable this option to test object aggregation manager on boot
2896 tristate "Test heap/page initialization"
2898 Test if the kernel is zero-initializing heap and page allocations.
2899 This can be useful to test init_on_alloc and init_on_free features.
2904 tristate "Test HMM (Heterogeneous Memory Management)"
2905 depends on TRANSPARENT_HUGEPAGE
2906 depends on DEVICE_PRIVATE
2910 This is a pseudo device driver solely for testing HMM.
2911 Say M here if you want to build the HMM test module.
2912 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2916 config TEST_FREE_PAGES
2917 tristate "Test freeing pages"
2919 Test that a memory leak does not occur due to a race between
2920 freeing a block of pages and a speculative page reference.
2921 Loading this module is safe if your kernel has the bug fixed.
2922 If the bug is not fixed, it will leak gigabytes of memory and
2923 probably OOM your system.
2926 tristate "Test floating point operations in kernel space"
2927 depends on ARCH_HAS_KERNEL_FPU_SUPPORT && !KCOV_INSTRUMENT_ALL
2929 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2930 which will trigger a sequence of floating point operations. This is used
2931 for self-testing floating point control register setting in
2936 config TEST_CLOCKSOURCE_WATCHDOG
2937 tristate "Test clocksource watchdog in kernel space"
2938 depends on CLOCKSOURCE_WATCHDOG
2940 Enable this option to create a kernel module that will trigger
2941 a test of the clocksource watchdog. This module may be loaded
2942 via modprobe or insmod in which case it will run upon being
2943 loaded, or it may be built in, in which case it will run
2949 tristate "Test module for correctness and stress of objpool"
2951 depends on m && DEBUG_KERNEL
2953 This builds the "test_objpool" module that should be used for
2954 correctness verification and concurrent testings of objects
2955 allocation and reclamation.
2959 endif # RUNTIME_TESTING_MENU
2961 config ARCH_USE_MEMTEST
2964 An architecture should select this when it uses early_memtest()
2965 during boot process.
2969 depends on ARCH_USE_MEMTEST
2971 This option adds a kernel parameter 'memtest', which allows memtest
2972 to be set and executed.
2973 memtest=0, mean disabled; -- default
2974 memtest=1, mean do 1 test pattern;
2976 memtest=17, mean do 17 test patterns.
2977 If you are unsure how to answer this question, answer N.
2981 config HYPERV_TESTING
2982 bool "Microsoft Hyper-V driver testing"
2984 depends on HYPERV && DEBUG_FS
2986 Select this option to enable Hyper-V vmbus testing.
2988 endmenu # "Kernel Testing and Coverage"
2992 config RUST_DEBUG_ASSERTIONS
2993 bool "Debug assertions"
2996 Enables rustc's `-Cdebug-assertions` codegen option.
2998 This flag lets you turn `cfg(debug_assertions)` conditional
2999 compilation on or off. This can be used to enable extra debugging
3000 code in development but not in production. For example, it controls
3001 the behavior of the standard library's `debug_assert!` macro.
3003 Note that this will apply to all Rust code, including `core`.
3007 config RUST_OVERFLOW_CHECKS
3008 bool "Overflow checks"
3012 Enables rustc's `-Coverflow-checks` codegen option.
3014 This flag allows you to control the behavior of runtime integer
3015 overflow. When overflow-checks are enabled, a Rust panic will occur
3018 Note that this will apply to all Rust code, including `core`.
3022 config RUST_BUILD_ASSERT_ALLOW
3023 bool "Allow unoptimized build-time assertions"
3026 Controls how are `build_error!` and `build_assert!` handled during build.
3028 If calls to them exist in the binary, it may indicate a violated invariant
3029 or that the optimizer failed to verify the invariant during compilation.
3031 This should not happen, thus by default the build is aborted. However,
3032 as an escape hatch, you can choose Y here to ignore them during build
3033 and let the check be carried at runtime (with `panic!` being called if
3038 config RUST_KERNEL_DOCTESTS
3039 bool "Doctests for the `kernel` crate" if !KUNIT_ALL_TESTS
3040 depends on RUST && KUNIT=y
3041 default KUNIT_ALL_TESTS
3043 This builds the documentation tests of the `kernel` crate
3046 For more information on KUnit and unit tests in general,
3047 please refer to the KUnit documentation in Documentation/dev-tools/kunit/.
3053 endmenu # Kernel hacking
projects / linux.git / blob