1 # SPDX-License-Identifier: GPL-2.0-only
4 menu "printk and dmesg options"
7 bool "Show timing information on printks"
10 Selecting this option causes time stamps of the printk()
11 messages to be added to the output of the syslog() system
12 call and at the console.
14 The timestamp is always recorded internally, and exported
15 to /dev/kmsg. This flag just specifies if the timestamp should
16 be included, not that the timestamp is recorded.
18 The behavior is also controlled by the kernel command line
19 parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
22 bool "Show caller information on printks"
25 Selecting this option causes printk() to add a caller "thread id" (if
26 in task context) or a caller "processor id" (if not in task context)
29 This option is intended for environments where multiple threads
30 concurrently call printk() for many times, for it is difficult to
31 interpret without knowing where these lines (or sometimes individual
32 line which was divided into multiple lines due to race) came from.
34 Since toggling after boot makes the code racy, currently there is
35 no option to enable/disable at the kernel command line parameter or
38 config CONSOLE_LOGLEVEL_DEFAULT
39 int "Default console loglevel (1-15)"
43 Default loglevel to determine what will be printed on the console.
45 Setting a default here is equivalent to passing in loglevel=<x> in
46 the kernel bootargs. loglevel=<x> continues to override whatever
47 value is specified here as well.
49 Note: This does not affect the log level of un-prefixed printk()
50 usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
53 config CONSOLE_LOGLEVEL_QUIET
54 int "quiet console loglevel (1-15)"
58 loglevel to use when "quiet" is passed on the kernel commandline.
60 When "quiet" is passed on the kernel commandline this loglevel
61 will be used as the loglevel. IOW passing "quiet" will be the
62 equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
64 config MESSAGE_LOGLEVEL_DEFAULT
65 int "Default message log level (1-7)"
69 Default log level for printk statements with no specified priority.
71 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
72 that are auditing their logs closely may want to set it to a lower
75 Note: This does not affect what message level gets printed on the console
76 by default. To change that, use loglevel=<x> in the kernel bootargs,
77 or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
79 config BOOT_PRINTK_DELAY
80 bool "Delay each boot printk message by N milliseconds"
81 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
83 This build option allows you to read kernel boot messages
84 by inserting a short delay after each one. The delay is
85 specified in milliseconds on the kernel command line,
88 It is likely that you would also need to use "lpj=M" to preset
89 the "loops per jiffie" value.
90 See a previous boot log for the "lpj" value to use for your
91 system, and then set "lpj=M" before setting "boot_delay=N".
92 NOTE: Using this option may adversely affect SMP systems.
93 I.e., processors other than the first one may not boot up.
94 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
95 what it believes to be lockup conditions.
98 bool "Enable dynamic printk() support"
101 depends on (DEBUG_FS || PROC_FS)
102 select DYNAMIC_DEBUG_CORE
105 Compiles debug level messages into the kernel, which would not
106 otherwise be available at runtime. These messages can then be
107 enabled/disabled based on various levels of scope - per source file,
108 function, module, format string, and line number. This mechanism
109 implicitly compiles in all pr_debug() and dev_dbg() calls, which
110 enlarges the kernel text size by about 2%.
112 If a source file is compiled with DEBUG flag set, any
113 pr_debug() calls in it are enabled by default, but can be
114 disabled at runtime as below. Note that DEBUG flag is
115 turned on by many CONFIG_*DEBUG* options.
119 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
120 which is contained in the 'debugfs' filesystem or procfs.
121 Thus, the debugfs or procfs filesystem must first be mounted before
122 making use of this feature.
123 We refer the control file as: <debugfs>/dynamic_debug/control. This
124 file contains a list of the debug statements that can be enabled. The
125 format for each line of the file is:
127 filename:lineno [module]function flags format
129 filename : source file of the debug statement
130 lineno : line number of the debug statement
131 module : module that contains the debug statement
132 function : function that contains the debug statement
133 flags : '=p' means the line is turned 'on' for printing
134 format : the format used for the debug statement
138 nullarbor:~ # cat <debugfs>/dynamic_debug/control
139 # filename:lineno [module]function flags format
140 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
141 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
142 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
146 // enable the message at line 1603 of file svcsock.c
147 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
148 <debugfs>/dynamic_debug/control
150 // enable all the messages in file svcsock.c
151 nullarbor:~ # echo -n 'file svcsock.c +p' >
152 <debugfs>/dynamic_debug/control
154 // enable all the messages in the NFS server module
155 nullarbor:~ # echo -n 'module nfsd +p' >
156 <debugfs>/dynamic_debug/control
158 // enable all 12 messages in the function svc_process()
159 nullarbor:~ # echo -n 'func svc_process +p' >
160 <debugfs>/dynamic_debug/control
162 // disable all 12 messages in the function svc_process()
163 nullarbor:~ # echo -n 'func svc_process -p' >
164 <debugfs>/dynamic_debug/control
166 See Documentation/admin-guide/dynamic-debug-howto.rst for additional
169 config DYNAMIC_DEBUG_CORE
170 bool "Enable core function of dynamic debug support"
172 depends on (DEBUG_FS || PROC_FS)
174 Enable core functional support of dynamic debug. It is useful
175 when you want to tie dynamic debug to your kernel modules with
176 DYNAMIC_DEBUG_MODULE defined for each of them, especially for
177 the case of embedded system where the kernel image size is
178 sensitive for people.
180 config SYMBOLIC_ERRNAME
181 bool "Support symbolic error names in printf"
184 If you say Y here, the kernel's printf implementation will
185 be able to print symbolic error names such as ENOSPC instead
186 of the number 28. It makes the kernel image slightly larger
187 (about 3KB), but can make the kernel logs easier to read.
189 config DEBUG_BUGVERBOSE
190 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
191 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
194 Say Y here to make BUG() panics output the file name and line number
195 of the BUG call as well as the EIP and oops trace. This aids
196 debugging but costs about 70-100K of memory.
198 endmenu # "printk and dmesg options"
200 menu "Compile-time checks and compiler options"
203 bool "Compile the kernel with debug info"
204 depends on DEBUG_KERNEL && !COMPILE_TEST
206 If you say Y here the resulting kernel image will include
207 debugging info resulting in a larger kernel image.
208 This adds debug symbols to the kernel and modules (gcc -g), and
209 is needed if you intend to use kernel crashdump or binary object
210 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
211 Say Y here only if you plan to debug the kernel.
217 config DEBUG_INFO_REDUCED
218 bool "Reduce debugging information"
220 If you say Y here gcc is instructed to generate less debugging
221 information for structure types. This means that tools that
222 need full debugging information (like kgdb or systemtap) won't
223 be happy. But if you merely need debugging information to
224 resolve line numbers there is no loss. Advantage is that
225 build directory object sizes shrink dramatically over a full
226 DEBUG_INFO build and compile times are reduced too.
227 Only works with newer gcc versions.
229 config DEBUG_INFO_COMPRESSED
230 bool "Compressed debugging information"
231 depends on $(cc-option,-gz=zlib)
232 depends on $(ld-option,--compress-debug-sections=zlib)
234 Compress the debug information using zlib. Requires GCC 5.0+ or Clang
235 5.0+, binutils 2.26+, and zlib.
237 Users of dpkg-deb via scripts/package/builddeb may find an increase in
238 size of their debug .deb packages with this config set, due to the
239 debug info being compressed with zlib, then the object files being
240 recompressed with a different compression scheme. But this is still
241 preferable to setting $KDEB_COMPRESS to "none" which would be even
244 config DEBUG_INFO_SPLIT
245 bool "Produce split debuginfo in .dwo files"
246 depends on $(cc-option,-gsplit-dwarf)
248 Generate debug info into separate .dwo files. This significantly
249 reduces the build directory size for builds with DEBUG_INFO,
250 because it stores the information only once on disk in .dwo
251 files instead of multiple times in object files and executables.
252 In addition the debug information is also compressed.
254 Requires recent gcc (4.7+) and recent gdb/binutils.
255 Any tool that packages or reads debug information would need
256 to know about the .dwo files and include them.
257 Incompatible with older versions of ccache.
260 prompt "DWARF version"
262 Which version of DWARF debug info to emit.
264 config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
265 bool "Rely on the toolchain's implicit default DWARF version"
267 The implicit default version of DWARF debug info produced by a
268 toolchain changes over time.
270 This can break consumers of the debug info that haven't upgraded to
271 support newer revisions, and prevent testing newer versions, but
272 those should be less common scenarios.
276 config DEBUG_INFO_DWARF4
277 bool "Generate DWARF Version 4 debuginfo"
279 Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+.
281 If you have consumers of DWARF debug info that are not ready for
282 newer revisions of DWARF, you may wish to choose this or have your
285 config DEBUG_INFO_DWARF5
286 bool "Generate DWARF Version 5 debuginfo"
287 depends on GCC_VERSION >= 50000 || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)))
288 depends on !DEBUG_INFO_BTF
290 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
291 5.0+ accepts the -gdwarf-5 flag but only had partial support for some
292 draft features until 7.0), and gdb 8.0+.
294 Changes to the structure of debug info in Version 5 allow for around
295 15-18% savings in resulting image and debug info section sizes as
296 compared to DWARF Version 4. DWARF Version 5 standardizes previous
297 extensions such as accelerators for symbol indexing and the format
298 for fission (.dwo/.dwp) files. Users may not want to select this
299 config if they rely on tooling that has not yet been updated to
300 support DWARF Version 5.
302 endchoice # "DWARF version"
304 config DEBUG_INFO_BTF
305 bool "Generate BTF typeinfo"
306 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
307 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
309 Generate deduplicated BTF type information from DWARF debug info.
310 Turning this on expects presence of pahole tool, which will convert
311 DWARF type info into equivalent deduplicated BTF type info.
313 config PAHOLE_HAS_SPLIT_BTF
314 def_bool $(success, test `$(PAHOLE) --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/'` -ge "119")
316 config DEBUG_INFO_BTF_MODULES
318 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
320 Generate compact split BTF type information for kernel modules.
323 bool "Provide GDB scripts for kernel debugging"
325 This creates the required links to GDB helper scripts in the
326 build directory. If you load vmlinux into gdb, the helper
327 scripts will be automatically imported by gdb as well, and
328 additional functions are available to analyze a Linux kernel
329 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
335 int "Warn for stack frames larger than"
337 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
338 default 1280 if (!64BIT && PARISC)
339 default 1024 if (!64BIT && !PARISC)
340 default 2048 if 64BIT
342 Tell gcc to warn at build time for stack frames larger than this.
343 Setting this too low will cause a lot of warnings.
344 Setting it to 0 disables the warning.
346 config STRIP_ASM_SYMS
347 bool "Strip assembler-generated symbols during link"
350 Strip internal assembler-generated symbols during a link (symbols
351 that look like '.Lxxx') so they don't pollute the output of
352 get_wchan() and suchlike.
355 bool "Generate readable assembler code"
356 depends on DEBUG_KERNEL
358 Disable some compiler optimizations that tend to generate human unreadable
359 assembler output. This may make the kernel slightly slower, but it helps
360 to keep kernel developers who have to stare a lot at assembler listings
363 config HEADERS_INSTALL
364 bool "Install uapi headers to usr/include"
367 This option will install uapi headers (headers exported to user-space)
368 into the usr/include directory for use during the kernel build.
369 This is unneeded for building the kernel itself, but needed for some
370 user-space program samples. It is also needed by some features such
371 as uapi header sanity checks.
373 config DEBUG_SECTION_MISMATCH
374 bool "Enable full Section mismatch analysis"
376 The section mismatch analysis checks if there are illegal
377 references from one section to another section.
378 During linktime or runtime, some sections are dropped;
379 any use of code/data previously in these sections would
380 most likely result in an oops.
381 In the code, functions and variables are annotated with
382 __init,, etc. (see the full list in include/linux/init.h),
383 which results in the code/data being placed in specific sections.
384 The section mismatch analysis is always performed after a full
385 kernel build, and enabling this option causes the following
386 additional step to occur:
387 - Add the option -fno-inline-functions-called-once to gcc commands.
388 When inlining a function annotated with __init in a non-init
389 function, we would lose the section information and thus
390 the analysis would not catch the illegal reference.
391 This option tells gcc to inline less (but it does result in
394 config SECTION_MISMATCH_WARN_ONLY
395 bool "Make section mismatch errors non-fatal"
398 If you say N here, the build process will fail if there are any
399 section mismatch, instead of just throwing warnings.
403 config DEBUG_FORCE_FUNCTION_ALIGN_32B
404 bool "Force all function address 32B aligned" if EXPERT
406 There are cases that a commit from one domain changes the function
407 address alignment of other domains, and cause magic performance
408 bump (regression or improvement). Enable this option will help to
409 verify if the bump is caused by function alignment changes, while
410 it will slightly increase the kernel size and affect icache usage.
412 It is mainly for debug and performance tuning use.
415 # Select this config option from the architecture Kconfig, if it
416 # is preferred to always offer frame pointers as a config
417 # option on the architecture (regardless of KERNEL_DEBUG):
419 config ARCH_WANT_FRAME_POINTERS
423 bool "Compile the kernel with frame pointers"
424 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
425 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
427 If you say Y here the resulting kernel image will be slightly
428 larger and slower, but it gives very useful debugging information
429 in case of kernel bugs. (precise oopses/stacktraces/warnings)
431 config STACK_VALIDATION
432 bool "Compile-time stack metadata validation"
433 depends on HAVE_STACK_VALIDATION
436 Add compile-time checks to validate stack metadata, including frame
437 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
438 that runtime stack traces are more reliable.
440 This is also a prerequisite for generation of ORC unwind data, which
441 is needed for CONFIG_UNWINDER_ORC.
443 For more information, see
444 tools/objtool/Documentation/stack-validation.txt.
446 config VMLINUX_VALIDATION
448 depends on STACK_VALIDATION && DEBUG_ENTRY && !PARAVIRT
452 bool "Generate vmlinux.map file when linking"
455 Selecting this option will pass "-Map=vmlinux.map" to ld
456 when linking vmlinux. That file can be useful for verifying
457 and debugging magic section games, and for seeing which
458 pieces of code get eliminated with
459 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
461 config DEBUG_FORCE_WEAK_PER_CPU
462 bool "Force weak per-cpu definitions"
463 depends on DEBUG_KERNEL
465 s390 and alpha require percpu variables in modules to be
466 defined weak to work around addressing range issue which
467 puts the following two restrictions on percpu variable
470 1. percpu symbols must be unique whether static or not
471 2. percpu variables can't be defined inside a function
473 To ensure that generic code follows the above rules, this
474 option forces all percpu variables to be defined as weak.
476 endmenu # "Compiler options"
478 menu "Generic Kernel Debugging Instruments"
481 bool "Magic SysRq key"
484 If you say Y here, you will have some control over the system even
485 if the system crashes for example during kernel debugging (e.g., you
486 will be able to flush the buffer cache to disk, reboot the system
487 immediately or dump some status information). This is accomplished
488 by pressing various keys while holding SysRq (Alt+PrintScreen). It
489 also works on a serial console (on PC hardware at least), if you
490 send a BREAK and then within 5 seconds a command keypress. The
491 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
492 Don't say Y unless you really know what this hack does.
494 config MAGIC_SYSRQ_DEFAULT_ENABLE
495 hex "Enable magic SysRq key functions by default"
496 depends on MAGIC_SYSRQ
499 Specifies which SysRq key functions are enabled by default.
500 This may be set to 1 or 0 to enable or disable them all, or
501 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
503 config MAGIC_SYSRQ_SERIAL
504 bool "Enable magic SysRq key over serial"
505 depends on MAGIC_SYSRQ
508 Many embedded boards have a disconnected TTL level serial which can
509 generate some garbage that can lead to spurious false sysrq detects.
510 This option allows you to decide whether you want to enable the
513 config MAGIC_SYSRQ_SERIAL_SEQUENCE
514 string "Char sequence that enables magic SysRq over serial"
515 depends on MAGIC_SYSRQ_SERIAL
518 Specifies a sequence of characters that can follow BREAK to enable
519 SysRq on a serial console.
521 If unsure, leave an empty string and the option will not be enabled.
524 bool "Debug Filesystem"
526 debugfs is a virtual file system that kernel developers use to put
527 debugging files into. Enable this option to be able to read and
528 write to these files.
530 For detailed documentation on the debugfs API, see
531 Documentation/filesystems/.
536 prompt "Debugfs default access"
538 default DEBUG_FS_ALLOW_ALL
540 This selects the default access restrictions for debugfs.
541 It can be overridden with kernel command line option
542 debugfs=[on,no-mount,off]. The restrictions apply for API access
543 and filesystem registration.
545 config DEBUG_FS_ALLOW_ALL
548 No restrictions apply. Both API and filesystem registration
549 is on. This is the normal default operation.
551 config DEBUG_FS_DISALLOW_MOUNT
552 bool "Do not register debugfs as filesystem"
554 The API is open but filesystem is not loaded. Clients can still do
555 their work and read with debug tools that do not need
558 config DEBUG_FS_ALLOW_NONE
561 Access is off. Clients get -PERM when trying to create nodes in
562 debugfs tree and debugfs is not registered as a filesystem.
563 Client can then back-off or continue without debugfs access.
567 source "lib/Kconfig.kgdb"
568 source "lib/Kconfig.ubsan"
569 source "lib/Kconfig.kcsan"
574 bool "Kernel debugging"
576 Say Y here if you are developing drivers or trying to debug and
577 identify kernel problems.
580 bool "Miscellaneous debug code"
582 depends on DEBUG_KERNEL
584 Say Y here if you need to enable miscellaneous debug code that should
585 be under a more specific debug option but isn't.
588 menu "Memory Debugging"
590 source "mm/Kconfig.debug"
593 bool "Debug object operations"
594 depends on DEBUG_KERNEL
596 If you say Y here, additional code will be inserted into the
597 kernel to track the life time of various objects and validate
598 the operations on those objects.
600 config DEBUG_OBJECTS_SELFTEST
601 bool "Debug objects selftest"
602 depends on DEBUG_OBJECTS
604 This enables the selftest of the object debug code.
606 config DEBUG_OBJECTS_FREE
607 bool "Debug objects in freed memory"
608 depends on DEBUG_OBJECTS
610 This enables checks whether a k/v free operation frees an area
611 which contains an object which has not been deactivated
612 properly. This can make kmalloc/kfree-intensive workloads
615 config DEBUG_OBJECTS_TIMERS
616 bool "Debug timer objects"
617 depends on DEBUG_OBJECTS
619 If you say Y here, additional code will be inserted into the
620 timer routines to track the life time of timer objects and
621 validate the timer operations.
623 config DEBUG_OBJECTS_WORK
624 bool "Debug work objects"
625 depends on DEBUG_OBJECTS
627 If you say Y here, additional code will be inserted into the
628 work queue routines to track the life time of work objects and
629 validate the work operations.
631 config DEBUG_OBJECTS_RCU_HEAD
632 bool "Debug RCU callbacks objects"
633 depends on DEBUG_OBJECTS
635 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
637 config DEBUG_OBJECTS_PERCPU_COUNTER
638 bool "Debug percpu counter objects"
639 depends on DEBUG_OBJECTS
641 If you say Y here, additional code will be inserted into the
642 percpu counter routines to track the life time of percpu counter
643 objects and validate the percpu counter operations.
645 config DEBUG_OBJECTS_ENABLE_DEFAULT
646 int "debug_objects bootup default value (0-1)"
649 depends on DEBUG_OBJECTS
651 Debug objects boot parameter default value
654 bool "Debug slab memory allocations"
655 depends on DEBUG_KERNEL && SLAB
657 Say Y here to have the kernel do limited verification on memory
658 allocation as well as poisoning memory on free to catch use of freed
659 memory. This can make kmalloc/kfree-intensive workloads much slower.
662 bool "SLUB debugging on by default"
663 depends on SLUB && SLUB_DEBUG
666 Boot with debugging on by default. SLUB boots by default with
667 the runtime debug capabilities switched off. Enabling this is
668 equivalent to specifying the "slub_debug" parameter on boot.
669 There is no support for more fine grained debug control like
670 possible with slub_debug=xxx. SLUB debugging may be switched
671 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
676 bool "Enable SLUB performance statistics"
677 depends on SLUB && SYSFS
679 SLUB statistics are useful to debug SLUBs allocation behavior in
680 order find ways to optimize the allocator. This should never be
681 enabled for production use since keeping statistics slows down
682 the allocator by a few percentage points. The slabinfo command
683 supports the determination of the most active slabs to figure
684 out which slabs are relevant to a particular load.
685 Try running: slabinfo -DA
687 config HAVE_DEBUG_KMEMLEAK
690 config DEBUG_KMEMLEAK
691 bool "Kernel memory leak detector"
692 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
694 select STACKTRACE if STACKTRACE_SUPPORT
698 Say Y here if you want to enable the memory leak
699 detector. The memory allocation/freeing is traced in a way
700 similar to the Boehm's conservative garbage collector, the
701 difference being that the orphan objects are not freed but
702 only shown in /sys/kernel/debug/kmemleak. Enabling this
703 feature will introduce an overhead to memory
704 allocations. See Documentation/dev-tools/kmemleak.rst for more
707 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
708 of finding leaks due to the slab objects poisoning.
710 In order to access the kmemleak file, debugfs needs to be
711 mounted (usually at /sys/kernel/debug).
713 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
714 int "Kmemleak memory pool size"
715 depends on DEBUG_KMEMLEAK
719 Kmemleak must track all the memory allocations to avoid
720 reporting false positives. Since memory may be allocated or
721 freed before kmemleak is fully initialised, use a static pool
722 of metadata objects to track such callbacks. After kmemleak is
723 fully initialised, this memory pool acts as an emergency one
724 if slab allocations fail.
726 config DEBUG_KMEMLEAK_TEST
727 tristate "Simple test for the kernel memory leak detector"
728 depends on DEBUG_KMEMLEAK && m
730 This option enables a module that explicitly leaks memory.
734 config DEBUG_KMEMLEAK_DEFAULT_OFF
735 bool "Default kmemleak to off"
736 depends on DEBUG_KMEMLEAK
738 Say Y here to disable kmemleak by default. It can then be enabled
739 on the command line via kmemleak=on.
741 config DEBUG_KMEMLEAK_AUTO_SCAN
742 bool "Enable kmemleak auto scan thread on boot up"
744 depends on DEBUG_KMEMLEAK
746 Depending on the cpu, kmemleak scan may be cpu intensive and can
747 stall user tasks at times. This option enables/disables automatic
748 kmemleak scan at boot up.
750 Say N here to disable kmemleak auto scan thread to stop automatic
751 scanning. Disabling this option disables automatic reporting of
756 config DEBUG_STACK_USAGE
757 bool "Stack utilization instrumentation"
758 depends on DEBUG_KERNEL && !IA64
760 Enables the display of the minimum amount of free stack which each
761 task has ever had available in the sysrq-T and sysrq-P debug output.
763 This option will slow down process creation somewhat.
765 config SCHED_STACK_END_CHECK
766 bool "Detect stack corruption on calls to schedule()"
767 depends on DEBUG_KERNEL
770 This option checks for a stack overrun on calls to schedule().
771 If the stack end location is found to be over written always panic as
772 the content of the corrupted region can no longer be trusted.
773 This is to ensure no erroneous behaviour occurs which could result in
774 data corruption or a sporadic crash at a later stage once the region
775 is examined. The runtime overhead introduced is minimal.
777 config ARCH_HAS_DEBUG_VM_PGTABLE
780 An architecture should select this when it can successfully
781 build and run DEBUG_VM_PGTABLE.
785 depends on DEBUG_KERNEL
787 Enable this to turn on extended checks in the virtual-memory system
788 that may impact performance.
792 config DEBUG_VM_VMACACHE
793 bool "Debug VMA caching"
796 Enable this to turn on VMA caching debug information. Doing so
797 can cause significant overhead, so only enable it in non-production
803 bool "Debug VM red-black trees"
806 Enable VM red-black tree debugging information and extra validations.
810 config DEBUG_VM_PGFLAGS
811 bool "Debug page-flags operations"
814 Enables extra validation on page flags operations.
818 config DEBUG_VM_PGTABLE
819 bool "Debug arch page table for semantics compliance"
821 depends on ARCH_HAS_DEBUG_VM_PGTABLE
822 default y if DEBUG_VM
824 This option provides a debug method which can be used to test
825 architecture page table helper functions on various platforms in
826 verifying if they comply with expected generic MM semantics. This
827 will help architecture code in making sure that any changes or
828 new additions of these helpers still conform to expected
829 semantics of the generic MM. Platforms will have to opt in for
830 this through ARCH_HAS_DEBUG_VM_PGTABLE.
834 config ARCH_HAS_DEBUG_VIRTUAL
838 bool "Debug VM translations"
839 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
841 Enable some costly sanity checks in virtual to page code. This can
842 catch mistakes with virt_to_page() and friends.
846 config DEBUG_NOMMU_REGIONS
847 bool "Debug the global anon/private NOMMU mapping region tree"
848 depends on DEBUG_KERNEL && !MMU
850 This option causes the global tree of anonymous and private mapping
851 regions to be regularly checked for invalid topology.
853 config DEBUG_MEMORY_INIT
854 bool "Debug memory initialisation" if EXPERT
857 Enable this for additional checks during memory initialisation.
858 The sanity checks verify aspects of the VM such as the memory model
859 and other information provided by the architecture. Verbose
860 information will be printed at KERN_DEBUG loglevel depending
861 on the mminit_loglevel= command-line option.
865 config MEMORY_NOTIFIER_ERROR_INJECT
866 tristate "Memory hotplug notifier error injection module"
867 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
869 This option provides the ability to inject artificial errors to
870 memory hotplug notifier chain callbacks. It is controlled through
871 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
873 If the notifier call chain should be failed with some events
874 notified, write the error code to "actions/<notifier event>/error".
876 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
878 # cd /sys/kernel/debug/notifier-error-inject/memory
879 # echo -12 > actions/MEM_GOING_OFFLINE/error
880 # echo offline > /sys/devices/system/memory/memoryXXX/state
881 bash: echo: write error: Cannot allocate memory
883 To compile this code as a module, choose M here: the module will
884 be called memory-notifier-error-inject.
888 config DEBUG_PER_CPU_MAPS
889 bool "Debug access to per_cpu maps"
890 depends on DEBUG_KERNEL
893 Say Y to verify that the per_cpu map being accessed has
894 been set up. This adds a fair amount of code to kernel memory
895 and decreases performance.
899 config DEBUG_KMAP_LOCAL
900 bool "Debug kmap_local temporary mappings"
901 depends on DEBUG_KERNEL && KMAP_LOCAL
903 This option enables additional error checking for the kmap_local
904 infrastructure. Disable for production use.
906 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
909 config DEBUG_KMAP_LOCAL_FORCE_MAP
910 bool "Enforce kmap_local temporary mappings"
911 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
913 select DEBUG_KMAP_LOCAL
915 This option enforces temporary mappings through the kmap_local
916 mechanism for non-highmem pages and on non-highmem systems.
917 Disable this for production systems!
920 bool "Highmem debugging"
921 depends on DEBUG_KERNEL && HIGHMEM
922 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
923 select DEBUG_KMAP_LOCAL
925 This option enables additional error checking for high memory
926 systems. Disable for production systems.
928 config HAVE_DEBUG_STACKOVERFLOW
931 config DEBUG_STACKOVERFLOW
932 bool "Check for stack overflows"
933 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
935 Say Y here if you want to check for overflows of kernel, IRQ
936 and exception stacks (if your architecture uses them). This
937 option will show detailed messages if free stack space drops
938 below a certain limit.
940 These kinds of bugs usually occur when call-chains in the
941 kernel get too deep, especially when interrupts are
944 Use this in cases where you see apparently random memory
945 corruption, especially if it appears in 'struct thread_info'
947 If in doubt, say "N".
949 source "lib/Kconfig.kasan"
950 source "lib/Kconfig.kfence"
952 endmenu # "Memory Debugging"
955 bool "Debug shared IRQ handlers"
956 depends on DEBUG_KERNEL
958 Enable this to generate a spurious interrupt just before a shared
959 interrupt handler is deregistered (generating one when registering
960 is currently disabled). Drivers need to handle this correctly. Some
961 don't and need to be caught.
963 menu "Debug Oops, Lockups and Hangs"
968 Say Y here to enable the kernel to panic when it oopses. This
969 has the same effect as setting oops=panic on the kernel command
972 This feature is useful to ensure that the kernel does not do
973 anything erroneous after an oops which could result in data
974 corruption or other issues.
978 config PANIC_ON_OOPS_VALUE
981 default 0 if !PANIC_ON_OOPS
982 default 1 if PANIC_ON_OOPS
988 Set the timeout value (in seconds) until a reboot occurs when
989 the kernel panics. If n = 0, then we wait forever. A timeout
990 value n > 0 will wait n seconds before rebooting, while a timeout
991 value n < 0 will reboot immediately.
993 config LOCKUP_DETECTOR
996 config SOFTLOCKUP_DETECTOR
997 bool "Detect Soft Lockups"
998 depends on DEBUG_KERNEL && !S390
999 select LOCKUP_DETECTOR
1001 Say Y here to enable the kernel to act as a watchdog to detect
1004 Softlockups are bugs that cause the kernel to loop in kernel
1005 mode for more than 20 seconds, without giving other tasks a
1006 chance to run. The current stack trace is displayed upon
1007 detection and the system will stay locked up.
1009 config BOOTPARAM_SOFTLOCKUP_PANIC
1010 bool "Panic (Reboot) On Soft Lockups"
1011 depends on SOFTLOCKUP_DETECTOR
1013 Say Y here to enable the kernel to panic on "soft lockups",
1014 which are bugs that cause the kernel to loop in kernel
1015 mode for more than 20 seconds (configurable using the watchdog_thresh
1016 sysctl), without giving other tasks a chance to run.
1018 The panic can be used in combination with panic_timeout,
1019 to cause the system to reboot automatically after a
1020 lockup has been detected. This feature is useful for
1021 high-availability systems that have uptime guarantees and
1022 where a lockup must be resolved ASAP.
1026 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
1028 depends on SOFTLOCKUP_DETECTOR
1030 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
1031 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
1033 config HARDLOCKUP_DETECTOR_PERF
1035 select SOFTLOCKUP_DETECTOR
1038 # Enables a timestamp based low pass filter to compensate for perf based
1039 # hard lockup detection which runs too fast due to turbo modes.
1041 config HARDLOCKUP_CHECK_TIMESTAMP
1045 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1046 # lockup detector rather than the perf based detector.
1048 config HARDLOCKUP_DETECTOR
1049 bool "Detect Hard Lockups"
1050 depends on DEBUG_KERNEL && !S390
1051 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1052 select LOCKUP_DETECTOR
1053 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1054 select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH
1056 Say Y here to enable the kernel to act as a watchdog to detect
1059 Hardlockups are bugs that cause the CPU to loop in kernel mode
1060 for more than 10 seconds, without letting other interrupts have a
1061 chance to run. The current stack trace is displayed upon detection
1062 and the system will stay locked up.
1064 config BOOTPARAM_HARDLOCKUP_PANIC
1065 bool "Panic (Reboot) On Hard Lockups"
1066 depends on HARDLOCKUP_DETECTOR
1068 Say Y here to enable the kernel to panic on "hard lockups",
1069 which are bugs that cause the kernel to loop in kernel
1070 mode with interrupts disabled for more than 10 seconds (configurable
1071 using the watchdog_thresh sysctl).
1075 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
1077 depends on HARDLOCKUP_DETECTOR
1079 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
1080 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
1082 config DETECT_HUNG_TASK
1083 bool "Detect Hung Tasks"
1084 depends on DEBUG_KERNEL
1085 default SOFTLOCKUP_DETECTOR
1087 Say Y here to enable the kernel to detect "hung tasks",
1088 which are bugs that cause the task to be stuck in
1089 uninterruptible "D" state indefinitely.
1091 When a hung task is detected, the kernel will print the
1092 current stack trace (which you should report), but the
1093 task will stay in uninterruptible state. If lockdep is
1094 enabled then all held locks will also be reported. This
1095 feature has negligible overhead.
1097 config DEFAULT_HUNG_TASK_TIMEOUT
1098 int "Default timeout for hung task detection (in seconds)"
1099 depends on DETECT_HUNG_TASK
1102 This option controls the default timeout (in seconds) used
1103 to determine when a task has become non-responsive and should
1106 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1107 sysctl or by writing a value to
1108 /proc/sys/kernel/hung_task_timeout_secs.
1110 A timeout of 0 disables the check. The default is two minutes.
1111 Keeping the default should be fine in most cases.
1113 config BOOTPARAM_HUNG_TASK_PANIC
1114 bool "Panic (Reboot) On Hung Tasks"
1115 depends on DETECT_HUNG_TASK
1117 Say Y here to enable the kernel to panic on "hung tasks",
1118 which are bugs that cause the kernel to leave a task stuck
1119 in uninterruptible "D" state.
1121 The panic can be used in combination with panic_timeout,
1122 to cause the system to reboot automatically after a
1123 hung task has been detected. This feature is useful for
1124 high-availability systems that have uptime guarantees and
1125 where a hung tasks must be resolved ASAP.
1129 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
1131 depends on DETECT_HUNG_TASK
1133 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
1134 default 1 if BOOTPARAM_HUNG_TASK_PANIC
1137 bool "Detect Workqueue Stalls"
1138 depends on DEBUG_KERNEL
1140 Say Y here to enable stall detection on workqueues. If a
1141 worker pool doesn't make forward progress on a pending work
1142 item for over a given amount of time, 30s by default, a
1143 warning message is printed along with dump of workqueue
1144 state. This can be configured through kernel parameter
1145 "workqueue.watchdog_thresh" and its sysfs counterpart.
1148 tristate "Test module to generate lockups"
1151 This builds the "test_lockup" module that helps to make sure
1152 that watchdogs and lockup detectors are working properly.
1154 Depending on module parameters it could emulate soft or hard
1155 lockup, "hung task", or locking arbitrary lock for a long time.
1156 Also it could generate series of lockups with cooling-down periods.
1160 endmenu # "Debug lockups and hangs"
1162 menu "Scheduler Debugging"
1165 bool "Collect scheduler debugging info"
1166 depends on DEBUG_KERNEL && PROC_FS
1169 If you say Y here, the /proc/sched_debug file will be provided
1170 that can help debug the scheduler. The runtime overhead of this
1178 bool "Collect scheduler statistics"
1179 depends on DEBUG_KERNEL && PROC_FS
1182 If you say Y here, additional code will be inserted into the
1183 scheduler and related routines to collect statistics about
1184 scheduler behavior and provide them in /proc/schedstat. These
1185 stats may be useful for both tuning and debugging the scheduler
1186 If you aren't debugging the scheduler or trying to tune a specific
1187 application, you can say N to avoid the very slight overhead
1192 config DEBUG_TIMEKEEPING
1193 bool "Enable extra timekeeping sanity checking"
1195 This option will enable additional timekeeping sanity checks
1196 which may be helpful when diagnosing issues where timekeeping
1197 problems are suspected.
1199 This may include checks in the timekeeping hotpaths, so this
1200 option may have a (very small) performance impact to some
1205 config DEBUG_PREEMPT
1206 bool "Debug preemptible kernel"
1207 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1210 If you say Y here then the kernel will use a debug variant of the
1211 commonly used smp_processor_id() function and will print warnings
1212 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1213 will detect preemption count underflows.
1215 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1217 config LOCK_DEBUGGING_SUPPORT
1219 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1222 config PROVE_LOCKING
1223 bool "Lock debugging: prove locking correctness"
1224 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1226 select DEBUG_SPINLOCK
1227 select DEBUG_MUTEXES
1228 select DEBUG_RT_MUTEXES if RT_MUTEXES
1230 select DEBUG_WW_MUTEX_SLOWPATH
1231 select DEBUG_LOCK_ALLOC
1232 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1233 select TRACE_IRQFLAGS
1236 This feature enables the kernel to prove that all locking
1237 that occurs in the kernel runtime is mathematically
1238 correct: that under no circumstance could an arbitrary (and
1239 not yet triggered) combination of observed locking
1240 sequences (on an arbitrary number of CPUs, running an
1241 arbitrary number of tasks and interrupt contexts) cause a
1244 In short, this feature enables the kernel to report locking
1245 related deadlocks before they actually occur.
1247 The proof does not depend on how hard and complex a
1248 deadlock scenario would be to trigger: how many
1249 participant CPUs, tasks and irq-contexts would be needed
1250 for it to trigger. The proof also does not depend on
1251 timing: if a race and a resulting deadlock is possible
1252 theoretically (no matter how unlikely the race scenario
1253 is), it will be proven so and will immediately be
1254 reported by the kernel (once the event is observed that
1255 makes the deadlock theoretically possible).
1257 If a deadlock is impossible (i.e. the locking rules, as
1258 observed by the kernel, are mathematically correct), the
1259 kernel reports nothing.
1261 NOTE: this feature can also be enabled for rwlocks, mutexes
1262 and rwsems - in which case all dependencies between these
1263 different locking variants are observed and mapped too, and
1264 the proof of observed correctness is also maintained for an
1265 arbitrary combination of these separate locking variants.
1267 For more details, see Documentation/locking/lockdep-design.rst.
1269 config PROVE_RAW_LOCK_NESTING
1270 bool "Enable raw_spinlock - spinlock nesting checks"
1271 depends on PROVE_LOCKING
1274 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1275 that the lock nesting rules for PREEMPT_RT enabled kernels are
1278 NOTE: There are known nesting problems. So if you enable this
1279 option expect lockdep splats until these problems have been fully
1280 addressed which is work in progress. This config switch allows to
1281 identify and analyze these problems. It will be removed and the
1282 check permanentely enabled once the main issues have been fixed.
1284 If unsure, select N.
1287 bool "Lock usage statistics"
1288 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1290 select DEBUG_SPINLOCK
1291 select DEBUG_MUTEXES
1292 select DEBUG_RT_MUTEXES if RT_MUTEXES
1293 select DEBUG_LOCK_ALLOC
1296 This feature enables tracking lock contention points
1298 For more details, see Documentation/locking/lockstat.rst
1300 This also enables lock events required by "perf lock",
1302 If you want to use "perf lock", you also need to turn on
1303 CONFIG_EVENT_TRACING.
1305 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1306 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1308 config DEBUG_RT_MUTEXES
1309 bool "RT Mutex debugging, deadlock detection"
1310 depends on DEBUG_KERNEL && RT_MUTEXES
1312 This allows rt mutex semantics violations and rt mutex related
1313 deadlocks (lockups) to be detected and reported automatically.
1315 config DEBUG_SPINLOCK
1316 bool "Spinlock and rw-lock debugging: basic checks"
1317 depends on DEBUG_KERNEL
1318 select UNINLINE_SPIN_UNLOCK
1320 Say Y here and build SMP to catch missing spinlock initialization
1321 and certain other kinds of spinlock errors commonly made. This is
1322 best used in conjunction with the NMI watchdog so that spinlock
1323 deadlocks are also debuggable.
1325 config DEBUG_MUTEXES
1326 bool "Mutex debugging: basic checks"
1327 depends on DEBUG_KERNEL
1329 This feature allows mutex semantics violations to be detected and
1332 config DEBUG_WW_MUTEX_SLOWPATH
1333 bool "Wait/wound mutex debugging: Slowpath testing"
1334 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1335 select DEBUG_LOCK_ALLOC
1336 select DEBUG_SPINLOCK
1337 select DEBUG_MUTEXES
1339 This feature enables slowpath testing for w/w mutex users by
1340 injecting additional -EDEADLK wound/backoff cases. Together with
1341 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1342 will test all possible w/w mutex interface abuse with the
1343 exception of simply not acquiring all the required locks.
1344 Note that this feature can introduce significant overhead, so
1345 it really should not be enabled in a production or distro kernel,
1346 even a debug kernel. If you are a driver writer, enable it. If
1347 you are a distro, do not.
1350 bool "RW Semaphore debugging: basic checks"
1351 depends on DEBUG_KERNEL
1353 This debugging feature allows mismatched rw semaphore locks
1354 and unlocks to be detected and reported.
1356 config DEBUG_LOCK_ALLOC
1357 bool "Lock debugging: detect incorrect freeing of live locks"
1358 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1359 select DEBUG_SPINLOCK
1360 select DEBUG_MUTEXES
1361 select DEBUG_RT_MUTEXES if RT_MUTEXES
1364 This feature will check whether any held lock (spinlock, rwlock,
1365 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1366 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1367 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1368 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1369 held during task exit.
1373 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1378 config LOCKDEP_SMALL
1382 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1383 depends on LOCKDEP && !LOCKDEP_SMALL
1387 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1389 config LOCKDEP_CHAINS_BITS
1390 int "Bitsize for MAX_LOCKDEP_CHAINS"
1391 depends on LOCKDEP && !LOCKDEP_SMALL
1395 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1397 config LOCKDEP_STACK_TRACE_BITS
1398 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1399 depends on LOCKDEP && !LOCKDEP_SMALL
1403 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1405 config LOCKDEP_STACK_TRACE_HASH_BITS
1406 int "Bitsize for STACK_TRACE_HASH_SIZE"
1407 depends on LOCKDEP && !LOCKDEP_SMALL
1411 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1413 config LOCKDEP_CIRCULAR_QUEUE_BITS
1414 int "Bitsize for elements in circular_queue struct"
1419 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1421 config DEBUG_LOCKDEP
1422 bool "Lock dependency engine debugging"
1423 depends on DEBUG_KERNEL && LOCKDEP
1424 select DEBUG_IRQFLAGS
1426 If you say Y here, the lock dependency engine will do
1427 additional runtime checks to debug itself, at the price
1428 of more runtime overhead.
1430 config DEBUG_ATOMIC_SLEEP
1431 bool "Sleep inside atomic section checking"
1432 select PREEMPT_COUNT
1433 depends on DEBUG_KERNEL
1434 depends on !ARCH_NO_PREEMPT
1436 If you say Y here, various routines which may sleep will become very
1437 noisy if they are called inside atomic sections: when a spinlock is
1438 held, inside an rcu read side critical section, inside preempt disabled
1439 sections, inside an interrupt, etc...
1441 config DEBUG_LOCKING_API_SELFTESTS
1442 bool "Locking API boot-time self-tests"
1443 depends on DEBUG_KERNEL
1445 Say Y here if you want the kernel to run a short self-test during
1446 bootup. The self-test checks whether common types of locking bugs
1447 are detected by debugging mechanisms or not. (if you disable
1448 lock debugging then those bugs wont be detected of course.)
1449 The following locking APIs are covered: spinlocks, rwlocks,
1452 config LOCK_TORTURE_TEST
1453 tristate "torture tests for locking"
1454 depends on DEBUG_KERNEL
1457 This option provides a kernel module that runs torture tests
1458 on kernel locking primitives. The kernel module may be built
1459 after the fact on the running kernel to be tested, if desired.
1461 Say Y here if you want kernel locking-primitive torture tests
1462 to be built into the kernel.
1463 Say M if you want these torture tests to build as a module.
1464 Say N if you are unsure.
1466 config WW_MUTEX_SELFTEST
1467 tristate "Wait/wound mutex selftests"
1469 This option provides a kernel module that runs tests on the
1470 on the struct ww_mutex locking API.
1472 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1473 with this test harness.
1475 Say M if you want these self tests to build as a module.
1476 Say N if you are unsure.
1478 config SCF_TORTURE_TEST
1479 tristate "torture tests for smp_call_function*()"
1480 depends on DEBUG_KERNEL
1483 This option provides a kernel module that runs torture tests
1484 on the smp_call_function() family of primitives. The kernel
1485 module may be built after the fact on the running kernel to
1486 be tested, if desired.
1488 config CSD_LOCK_WAIT_DEBUG
1489 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1490 depends on DEBUG_KERNEL
1494 This option enables debug prints when CPUs are slow to respond
1495 to the smp_call_function*() IPI wrappers. These debug prints
1496 include the IPI handler function currently executing (if any)
1497 and relevant stack traces.
1499 endmenu # lock debugging
1501 config TRACE_IRQFLAGS
1502 depends on TRACE_IRQFLAGS_SUPPORT
1505 Enables hooks to interrupt enabling and disabling for
1506 either tracing or lock debugging.
1508 config TRACE_IRQFLAGS_NMI
1510 depends on TRACE_IRQFLAGS
1511 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1513 config DEBUG_IRQFLAGS
1514 bool "Debug IRQ flag manipulation"
1516 Enables checks for potentially unsafe enabling or disabling of
1517 interrupts, such as calling raw_local_irq_restore() when interrupts
1521 bool "Stack backtrace support"
1522 depends on STACKTRACE_SUPPORT
1524 This option causes the kernel to create a /proc/pid/stack for
1525 every process, showing its current stack trace.
1526 It is also used by various kernel debugging features that require
1527 stack trace generation.
1529 config WARN_ALL_UNSEEDED_RANDOM
1530 bool "Warn for all uses of unseeded randomness"
1533 Some parts of the kernel contain bugs relating to their use of
1534 cryptographically secure random numbers before it's actually possible
1535 to generate those numbers securely. This setting ensures that these
1536 flaws don't go unnoticed, by enabling a message, should this ever
1537 occur. This will allow people with obscure setups to know when things
1538 are going wrong, so that they might contact developers about fixing
1541 Unfortunately, on some models of some architectures getting
1542 a fully seeded CRNG is extremely difficult, and so this can
1543 result in dmesg getting spammed for a surprisingly long
1544 time. This is really bad from a security perspective, and
1545 so architecture maintainers really need to do what they can
1546 to get the CRNG seeded sooner after the system is booted.
1547 However, since users cannot do anything actionable to
1548 address this, by default the kernel will issue only a single
1549 warning for the first use of unseeded randomness.
1551 Say Y here if you want to receive warnings for all uses of
1552 unseeded randomness. This will be of use primarily for
1553 those developers interested in improving the security of
1554 Linux kernels running on their architecture (or
1557 config DEBUG_KOBJECT
1558 bool "kobject debugging"
1559 depends on DEBUG_KERNEL
1561 If you say Y here, some extra kobject debugging messages will be sent
1564 config DEBUG_KOBJECT_RELEASE
1565 bool "kobject release debugging"
1566 depends on DEBUG_OBJECTS_TIMERS
1568 kobjects are reference counted objects. This means that their
1569 last reference count put is not predictable, and the kobject can
1570 live on past the point at which a driver decides to drop it's
1571 initial reference to the kobject gained on allocation. An
1572 example of this would be a struct device which has just been
1575 However, some buggy drivers assume that after such an operation,
1576 the memory backing the kobject can be immediately freed. This
1577 goes completely against the principles of a refcounted object.
1579 If you say Y here, the kernel will delay the release of kobjects
1580 on the last reference count to improve the visibility of this
1581 kind of kobject release bug.
1583 config HAVE_DEBUG_BUGVERBOSE
1586 menu "Debug kernel data structures"
1589 bool "Debug linked list manipulation"
1590 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1592 Enable this to turn on extended checks in the linked-list
1598 bool "Debug priority linked list manipulation"
1599 depends on DEBUG_KERNEL
1601 Enable this to turn on extended checks in the priority-ordered
1602 linked-list (plist) walking routines. This checks the entire
1603 list multiple times during each manipulation.
1608 bool "Debug SG table operations"
1609 depends on DEBUG_KERNEL
1611 Enable this to turn on checks on scatter-gather tables. This can
1612 help find problems with drivers that do not properly initialize
1617 config DEBUG_NOTIFIERS
1618 bool "Debug notifier call chains"
1619 depends on DEBUG_KERNEL
1621 Enable this to turn on sanity checking for notifier call chains.
1622 This is most useful for kernel developers to make sure that
1623 modules properly unregister themselves from notifier chains.
1624 This is a relatively cheap check but if you care about maximum
1627 config BUG_ON_DATA_CORRUPTION
1628 bool "Trigger a BUG when data corruption is detected"
1631 Select this option if the kernel should BUG when it encounters
1632 data corruption in kernel memory structures when they get checked
1639 config DEBUG_CREDENTIALS
1640 bool "Debug credential management"
1641 depends on DEBUG_KERNEL
1643 Enable this to turn on some debug checking for credential
1644 management. The additional code keeps track of the number of
1645 pointers from task_structs to any given cred struct, and checks to
1646 see that this number never exceeds the usage count of the cred
1649 Furthermore, if SELinux is enabled, this also checks that the
1650 security pointer in the cred struct is never seen to be invalid.
1654 source "kernel/rcu/Kconfig.debug"
1656 config DEBUG_WQ_FORCE_RR_CPU
1657 bool "Force round-robin CPU selection for unbound work items"
1658 depends on DEBUG_KERNEL
1661 Workqueue used to implicitly guarantee that work items queued
1662 without explicit CPU specified are put on the local CPU. This
1663 guarantee is no longer true and while local CPU is still
1664 preferred work items may be put on foreign CPUs. Kernel
1665 parameter "workqueue.debug_force_rr_cpu" is added to force
1666 round-robin CPU selection to flush out usages which depend on the
1667 now broken guarantee. This config option enables the debug
1668 feature by default. When enabled, memory and cache locality will
1671 config DEBUG_BLOCK_EXT_DEVT
1672 bool "Force extended block device numbers and spread them"
1673 depends on DEBUG_KERNEL
1677 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1678 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1679 YOU ARE DOING. Distros, please enable this and fix whatever
1682 Conventionally, block device numbers are allocated from
1683 predetermined contiguous area. However, extended block area
1684 may introduce non-contiguous block device numbers. This
1685 option forces most block device numbers to be allocated from
1686 the extended space and spreads them to discover kernel or
1687 userland code paths which assume predetermined contiguous
1688 device number allocation.
1690 Note that turning on this debug option shuffles all the
1691 device numbers for all IDE and SCSI devices including libata
1692 ones, so root partition specified using device number
1693 directly (via rdev or root=MAJ:MIN) won't work anymore.
1694 Textual device names (root=/dev/sdXn) will continue to work.
1696 Say N if you are unsure.
1698 config CPU_HOTPLUG_STATE_CONTROL
1699 bool "Enable CPU hotplug state control"
1700 depends on DEBUG_KERNEL
1701 depends on HOTPLUG_CPU
1704 Allows to write steps between "offline" and "online" to the CPUs
1705 sysfs target file so states can be stepped granular. This is a debug
1706 option for now as the hotplug machinery cannot be stopped and
1707 restarted at arbitrary points yet.
1709 Say N if your are unsure.
1712 bool "Latency measuring infrastructure"
1713 depends on DEBUG_KERNEL
1714 depends on STACKTRACE_SUPPORT
1716 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1722 Enable this option if you want to use the LatencyTOP tool
1723 to find out which userspace is blocking on what kernel operations.
1725 source "kernel/trace/Kconfig"
1727 config PROVIDE_OHCI1394_DMA_INIT
1728 bool "Remote debugging over FireWire early on boot"
1729 depends on PCI && X86
1731 If you want to debug problems which hang or crash the kernel early
1732 on boot and the crashing machine has a FireWire port, you can use
1733 this feature to remotely access the memory of the crashed machine
1734 over FireWire. This employs remote DMA as part of the OHCI1394
1735 specification which is now the standard for FireWire controllers.
1737 With remote DMA, you can monitor the printk buffer remotely using
1738 firescope and access all memory below 4GB using fireproxy from gdb.
1739 Even controlling a kernel debugger is possible using remote DMA.
1743 If ohci1394_dma=early is used as boot parameter, it will initialize
1744 all OHCI1394 controllers which are found in the PCI config space.
1746 As all changes to the FireWire bus such as enabling and disabling
1747 devices cause a bus reset and thereby disable remote DMA for all
1748 devices, be sure to have the cable plugged and FireWire enabled on
1749 the debugging host before booting the debug target for debugging.
1751 This code (~1k) is freed after boot. By then, the firewire stack
1752 in charge of the OHCI-1394 controllers should be used instead.
1754 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1756 source "samples/Kconfig"
1758 config ARCH_HAS_DEVMEM_IS_ALLOWED
1761 config STRICT_DEVMEM
1762 bool "Filter access to /dev/mem"
1763 depends on MMU && DEVMEM
1764 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1765 default y if PPC || X86 || ARM64
1767 If this option is disabled, you allow userspace (root) access to all
1768 of memory, including kernel and userspace memory. Accidental
1769 access to this is obviously disastrous, but specific access can
1770 be used by people debugging the kernel. Note that with PAT support
1771 enabled, even in this case there are restrictions on /dev/mem
1772 use due to the cache aliasing requirements.
1774 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1775 file only allows userspace access to PCI space and the BIOS code and
1776 data regions. This is sufficient for dosemu and X and all common
1781 config IO_STRICT_DEVMEM
1782 bool "Filter I/O access to /dev/mem"
1783 depends on STRICT_DEVMEM
1785 If this option is disabled, you allow userspace (root) access to all
1786 io-memory regardless of whether a driver is actively using that
1787 range. Accidental access to this is obviously disastrous, but
1788 specific access can be used by people debugging kernel drivers.
1790 If this option is switched on, the /dev/mem file only allows
1791 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1792 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1793 if the driver using a given range cannot be disabled.
1797 menu "$(SRCARCH) Debugging"
1799 source "arch/$(SRCARCH)/Kconfig.debug"
1803 menu "Kernel Testing and Coverage"
1805 source "lib/kunit/Kconfig"
1807 config NOTIFIER_ERROR_INJECTION
1808 tristate "Notifier error injection"
1809 depends on DEBUG_KERNEL
1812 This option provides the ability to inject artificial errors to
1813 specified notifier chain callbacks. It is useful to test the error
1814 handling of notifier call chain failures.
1818 config PM_NOTIFIER_ERROR_INJECT
1819 tristate "PM notifier error injection module"
1820 depends on PM && NOTIFIER_ERROR_INJECTION
1821 default m if PM_DEBUG
1823 This option provides the ability to inject artificial errors to
1824 PM notifier chain callbacks. It is controlled through debugfs
1825 interface /sys/kernel/debug/notifier-error-inject/pm
1827 If the notifier call chain should be failed with some events
1828 notified, write the error code to "actions/<notifier event>/error".
1830 Example: Inject PM suspend error (-12 = -ENOMEM)
1832 # cd /sys/kernel/debug/notifier-error-inject/pm/
1833 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1834 # echo mem > /sys/power/state
1835 bash: echo: write error: Cannot allocate memory
1837 To compile this code as a module, choose M here: the module will
1838 be called pm-notifier-error-inject.
1842 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1843 tristate "OF reconfig notifier error injection module"
1844 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1846 This option provides the ability to inject artificial errors to
1847 OF reconfig notifier chain callbacks. It is controlled
1848 through debugfs interface under
1849 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1851 If the notifier call chain should be failed with some events
1852 notified, write the error code to "actions/<notifier event>/error".
1854 To compile this code as a module, choose M here: the module will
1855 be called of-reconfig-notifier-error-inject.
1859 config NETDEV_NOTIFIER_ERROR_INJECT
1860 tristate "Netdev notifier error injection module"
1861 depends on NET && NOTIFIER_ERROR_INJECTION
1863 This option provides the ability to inject artificial errors to
1864 netdevice notifier chain callbacks. It is controlled through debugfs
1865 interface /sys/kernel/debug/notifier-error-inject/netdev
1867 If the notifier call chain should be failed with some events
1868 notified, write the error code to "actions/<notifier event>/error".
1870 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1872 # cd /sys/kernel/debug/notifier-error-inject/netdev
1873 # echo -22 > actions/NETDEV_CHANGEMTU/error
1874 # ip link set eth0 mtu 1024
1875 RTNETLINK answers: Invalid argument
1877 To compile this code as a module, choose M here: the module will
1878 be called netdev-notifier-error-inject.
1882 config FUNCTION_ERROR_INJECTION
1884 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1886 config FAULT_INJECTION
1887 bool "Fault-injection framework"
1888 depends on DEBUG_KERNEL
1890 Provide fault-injection framework.
1891 For more details, see Documentation/fault-injection/.
1894 bool "Fault-injection capability for kmalloc"
1895 depends on FAULT_INJECTION
1896 depends on SLAB || SLUB
1898 Provide fault-injection capability for kmalloc.
1900 config FAIL_PAGE_ALLOC
1901 bool "Fault-injection capability for alloc_pages()"
1902 depends on FAULT_INJECTION
1904 Provide fault-injection capability for alloc_pages().
1906 config FAULT_INJECTION_USERCOPY
1907 bool "Fault injection capability for usercopy functions"
1908 depends on FAULT_INJECTION
1910 Provides fault-injection capability to inject failures
1911 in usercopy functions (copy_from_user(), get_user(), ...).
1913 config FAIL_MAKE_REQUEST
1914 bool "Fault-injection capability for disk IO"
1915 depends on FAULT_INJECTION && BLOCK
1917 Provide fault-injection capability for disk IO.
1919 config FAIL_IO_TIMEOUT
1920 bool "Fault-injection capability for faking disk interrupts"
1921 depends on FAULT_INJECTION && BLOCK
1923 Provide fault-injection capability on end IO handling. This
1924 will make the block layer "forget" an interrupt as configured,
1925 thus exercising the error handling.
1927 Only works with drivers that use the generic timeout handling,
1928 for others it wont do anything.
1931 bool "Fault-injection capability for futexes"
1933 depends on FAULT_INJECTION && FUTEX
1935 Provide fault-injection capability for futexes.
1937 config FAULT_INJECTION_DEBUG_FS
1938 bool "Debugfs entries for fault-injection capabilities"
1939 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1941 Enable configuration of fault-injection capabilities via debugfs.
1943 config FAIL_FUNCTION
1944 bool "Fault-injection capability for functions"
1945 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1947 Provide function-based fault-injection capability.
1948 This will allow you to override a specific function with a return
1949 with given return value. As a result, function caller will see
1950 an error value and have to handle it. This is useful to test the
1951 error handling in various subsystems.
1953 config FAIL_MMC_REQUEST
1954 bool "Fault-injection capability for MMC IO"
1955 depends on FAULT_INJECTION_DEBUG_FS && MMC
1957 Provide fault-injection capability for MMC IO.
1958 This will make the mmc core return data errors. This is
1959 useful to test the error handling in the mmc block device
1960 and to test how the mmc host driver handles retries from
1963 config FAULT_INJECTION_STACKTRACE_FILTER
1964 bool "stacktrace filter for fault-injection capabilities"
1965 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1968 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1970 Provide stacktrace filter for fault-injection capabilities
1972 config ARCH_HAS_KCOV
1975 An architecture should select this when it can successfully
1976 build and run with CONFIG_KCOV. This typically requires
1977 disabling instrumentation for some early boot code.
1979 config CC_HAS_SANCOV_TRACE_PC
1980 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1984 bool "Code coverage for fuzzing"
1985 depends on ARCH_HAS_KCOV
1986 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1988 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1990 KCOV exposes kernel code coverage information in a form suitable
1991 for coverage-guided fuzzing (randomized testing).
1993 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1994 different machines and across reboots. If you need stable PC values,
1995 disable RANDOMIZE_BASE.
1997 For more details, see Documentation/dev-tools/kcov.rst.
1999 config KCOV_ENABLE_COMPARISONS
2000 bool "Enable comparison operands collection by KCOV"
2002 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2004 KCOV also exposes operands of every comparison in the instrumented
2005 code along with operand sizes and PCs of the comparison instructions.
2006 These operands can be used by fuzzing engines to improve the quality
2007 of fuzzing coverage.
2009 config KCOV_INSTRUMENT_ALL
2010 bool "Instrument all code by default"
2014 If you are doing generic system call fuzzing (like e.g. syzkaller),
2015 then you will want to instrument the whole kernel and you should
2016 say y here. If you are doing more targeted fuzzing (like e.g.
2017 filesystem fuzzing with AFL) then you will want to enable coverage
2018 for more specific subsets of files, and should say n here.
2020 config KCOV_IRQ_AREA_SIZE
2021 hex "Size of interrupt coverage collection area in words"
2025 KCOV uses preallocated per-cpu areas to collect coverage from
2026 soft interrupts. This specifies the size of those areas in the
2027 number of unsigned long words.
2029 menuconfig RUNTIME_TESTING_MENU
2030 bool "Runtime Testing"
2033 if RUNTIME_TESTING_MENU
2036 tristate "Linux Kernel Dump Test Tool Module"
2039 This module enables testing of the different dumping mechanisms by
2040 inducing system failures at predefined crash points.
2041 If you don't need it: say N
2042 Choose M here to compile this code as a module. The module will be
2045 Documentation on how to use the module can be found in
2046 Documentation/fault-injection/provoke-crashes.rst
2048 config TEST_LIST_SORT
2049 tristate "Linked list sorting test"
2050 depends on DEBUG_KERNEL || m
2052 Enable this to turn on 'list_sort()' function test. This test is
2053 executed only once during system boot (so affects only boot time),
2054 or at module load time.
2058 config TEST_MIN_HEAP
2059 tristate "Min heap test"
2060 depends on DEBUG_KERNEL || m
2062 Enable this to turn on min heap function tests. This test is
2063 executed only once during system boot (so affects only boot time),
2064 or at module load time.
2069 tristate "Array-based sort test"
2070 depends on DEBUG_KERNEL || m
2072 This option enables the self-test function of 'sort()' at boot,
2073 or at module load time.
2078 tristate "64bit/32bit division and modulo test"
2079 depends on DEBUG_KERNEL || m
2081 Enable this to turn on 'do_div()' function test. This test is
2082 executed only once during system boot (so affects only boot time),
2083 or at module load time.
2087 config KPROBES_SANITY_TEST
2088 bool "Kprobes sanity tests"
2089 depends on DEBUG_KERNEL
2092 This option provides for testing basic kprobes functionality on
2093 boot. Samples of kprobe and kretprobe are inserted and
2094 verified for functionality.
2096 Say N if you are unsure.
2098 config BACKTRACE_SELF_TEST
2099 tristate "Self test for the backtrace code"
2100 depends on DEBUG_KERNEL
2102 This option provides a kernel module that can be used to test
2103 the kernel stack backtrace code. This option is not useful
2104 for distributions or general kernels, but only for kernel
2105 developers working on architecture code.
2107 Note that if you want to also test saved backtraces, you will
2108 have to enable STACKTRACE as well.
2110 Say N if you are unsure.
2113 tristate "Red-Black tree test"
2114 depends on DEBUG_KERNEL
2116 A benchmark measuring the performance of the rbtree library.
2117 Also includes rbtree invariant checks.
2119 config REED_SOLOMON_TEST
2120 tristate "Reed-Solomon library test"
2121 depends on DEBUG_KERNEL || m
2123 select REED_SOLOMON_ENC16
2124 select REED_SOLOMON_DEC16
2126 This option enables the self-test function of rslib at boot,
2127 or at module load time.
2131 config INTERVAL_TREE_TEST
2132 tristate "Interval tree test"
2133 depends on DEBUG_KERNEL
2134 select INTERVAL_TREE
2136 A benchmark measuring the performance of the interval tree library
2139 tristate "Per cpu operations test"
2140 depends on m && DEBUG_KERNEL
2142 Enable this option to build test module which validates per-cpu
2147 config ATOMIC64_SELFTEST
2148 tristate "Perform an atomic64_t self-test"
2150 Enable this option to test the atomic64_t functions at boot or
2151 at module load time.
2155 config ASYNC_RAID6_TEST
2156 tristate "Self test for hardware accelerated raid6 recovery"
2157 depends on ASYNC_RAID6_RECOV
2160 This is a one-shot self test that permutes through the
2161 recovery of all the possible two disk failure scenarios for a
2162 N-disk array. Recovery is performed with the asynchronous
2163 raid6 recovery routines, and will optionally use an offload
2164 engine if one is available.
2169 tristate "Test functions located in the hexdump module at runtime"
2171 config TEST_STRING_HELPERS
2172 tristate "Test functions located in the string_helpers module at runtime"
2175 tristate "Test strscpy*() family of functions at runtime"
2178 tristate "Test kstrto*() family of functions at runtime"
2181 tristate "Test printf() family of functions at runtime"
2184 tristate "Test bitmap_*() family of functions at runtime"
2186 Enable this option to test the bitmap functions at boot.
2191 tristate "Test functions located in the uuid module at runtime"
2194 tristate "Test the XArray code at runtime"
2196 config TEST_OVERFLOW
2197 tristate "Test check_*_overflow() functions at runtime"
2199 config TEST_RHASHTABLE
2200 tristate "Perform selftest on resizable hash table"
2202 Enable this option to test the rhashtable functions at boot.
2207 tristate "Perform selftest on hash functions"
2209 Enable this option to test the kernel's integer (<linux/hash.h>),
2210 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
2211 hash functions on boot (or module load).
2213 This is intended to help people writing architecture-specific
2214 optimized versions. If unsure, say N.
2217 tristate "Perform selftest on IDA functions"
2220 tristate "Perform selftest on priority array manager"
2223 Enable this option to test priority array manager on boot
2228 config TEST_IRQ_TIMINGS
2229 bool "IRQ timings selftest"
2230 depends on IRQ_TIMINGS
2232 Enable this option to test the irq timings code on boot.
2237 tristate "Test module loading with 'hello world' module"
2240 This builds the "test_module" module that emits "Hello, world"
2241 on printk when loaded. It is designed to be used for basic
2242 evaluation of the module loading subsystem (for example when
2243 validating module verification). It lacks any extra dependencies,
2244 and will not normally be loaded by the system unless explicitly
2250 tristate "Test module for compilation of bitops operations"
2253 This builds the "test_bitops" module that is much like the
2254 TEST_LKM module except that it does a basic exercise of the
2255 set/clear_bit macros and get_count_order/long to make sure there are
2256 no compiler warnings from C=1 sparse checker or -Wextra
2257 compilations. It has no dependencies and doesn't run or load unless
2258 explicitly requested by name. for example: modprobe test_bitops.
2263 tristate "Test module for stress/performance analysis of vmalloc allocator"
2268 This builds the "test_vmalloc" module that should be used for
2269 stress and performance analysis. So, any new change for vmalloc
2270 subsystem can be evaluated from performance and stability point
2275 config TEST_USER_COPY
2276 tristate "Test user/kernel boundary protections"
2279 This builds the "test_user_copy" module that runs sanity checks
2280 on the copy_to/from_user infrastructure, making sure basic
2281 user/kernel boundary testing is working. If it fails to load,
2282 a regression has been detected in the user/kernel memory boundary
2288 tristate "Test BPF filter functionality"
2291 This builds the "test_bpf" module that runs various test vectors
2292 against the BPF interpreter or BPF JIT compiler depending on the
2293 current setting. This is in particular useful for BPF JIT compiler
2294 development, but also to run regression tests against changes in
2295 the interpreter code. It also enables test stubs for eBPF maps and
2296 verifier used by user space verifier testsuite.
2300 config TEST_BLACKHOLE_DEV
2301 tristate "Test blackhole netdev functionality"
2304 This builds the "test_blackhole_dev" module that validates the
2305 data path through this blackhole netdev.
2309 config FIND_BIT_BENCHMARK
2310 tristate "Test find_bit functions"
2312 This builds the "test_find_bit" module that measure find_*_bit()
2313 functions performance.
2317 config TEST_FIRMWARE
2318 tristate "Test firmware loading via userspace interface"
2319 depends on FW_LOADER
2321 This builds the "test_firmware" module that creates a userspace
2322 interface for testing firmware loading. This can be used to
2323 control the triggering of firmware loading without needing an
2324 actual firmware-using device. The contents can be rechecked by
2330 tristate "sysctl test driver"
2331 depends on PROC_SYSCTL
2333 This builds the "test_sysctl" module. This driver enables to test the
2334 proc sysctl interfaces available to drivers safely without affecting
2335 production knobs which might alter system functionality.
2339 config BITFIELD_KUNIT
2340 tristate "KUnit test bitfield functions at runtime"
2343 Enable this option to test the bitfield functions at boot.
2345 KUnit tests run during boot and output the results to the debug log
2346 in TAP format (http://testanything.org/). Only useful for kernel devs
2347 running the KUnit test harness, and not intended for inclusion into a
2350 For more information on KUnit and unit tests in general please refer
2351 to the KUnit documentation in Documentation/dev-tools/kunit/.
2355 config RESOURCE_KUNIT_TEST
2356 tristate "KUnit test for resource API"
2359 This builds the resource API unit test.
2360 Tests the logic of API provided by resource.c and ioport.h.
2361 For more information on KUnit and unit tests in general please refer
2362 to the KUnit documentation in Documentation/dev-tools/kunit/.
2366 config SYSCTL_KUNIT_TEST
2367 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2369 default KUNIT_ALL_TESTS
2371 This builds the proc sysctl unit test, which runs on boot.
2372 Tests the API contract and implementation correctness of sysctl.
2373 For more information on KUnit and unit tests in general please refer
2374 to the KUnit documentation in Documentation/dev-tools/kunit/.
2378 config LIST_KUNIT_TEST
2379 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2381 default KUNIT_ALL_TESTS
2383 This builds the linked list KUnit test suite.
2384 It tests that the API and basic functionality of the list_head type
2385 and associated macros.
2387 KUnit tests run during boot and output the results to the debug log
2388 in TAP format (https://testanything.org/). Only useful for kernel devs
2389 running the KUnit test harness, and not intended for inclusion into a
2392 For more information on KUnit and unit tests in general please refer
2393 to the KUnit documentation in Documentation/dev-tools/kunit/.
2397 config LINEAR_RANGES_TEST
2398 tristate "KUnit test for linear_ranges"
2400 select LINEAR_RANGES
2402 This builds the linear_ranges unit test, which runs on boot.
2403 Tests the linear_ranges logic correctness.
2404 For more information on KUnit and unit tests in general please refer
2405 to the KUnit documentation in Documentation/dev-tools/kunit/.
2409 config CMDLINE_KUNIT_TEST
2410 tristate "KUnit test for cmdline API"
2413 This builds the cmdline API unit test.
2414 Tests the logic of API provided by cmdline.c.
2415 For more information on KUnit and unit tests in general please refer
2416 to the KUnit documentation in Documentation/dev-tools/kunit/.
2421 tristate "KUnit test for bits.h"
2424 This builds the bits unit test.
2425 Tests the logic of macros defined in bits.h.
2426 For more information on KUnit and unit tests in general please refer
2427 to the KUnit documentation in Documentation/dev-tools/kunit/.
2432 tristate "udelay test driver"
2434 This builds the "udelay_test" module that helps to make sure
2435 that udelay() is working properly.
2439 config TEST_STATIC_KEYS
2440 tristate "Test static keys"
2443 Test the static key interfaces.
2448 tristate "kmod stress tester"
2450 depends on NETDEVICES && NET_CORE && INET # for TUN
2457 Test the kernel's module loading mechanism: kmod. kmod implements
2458 support to load modules using the Linux kernel's usermode helper.
2459 This test provides a series of tests against kmod.
2461 Although technically you can either build test_kmod as a module or
2462 into the kernel we disallow building it into the kernel since
2463 it stress tests request_module() and this will very likely cause
2464 some issues by taking over precious threads available from other
2465 module load requests, ultimately this could be fatal.
2469 tools/testing/selftests/kmod/kmod.sh --help
2473 config TEST_DEBUG_VIRTUAL
2474 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2475 depends on DEBUG_VIRTUAL
2477 Test the kernel's ability to detect incorrect calls to
2478 virt_to_phys() done against the non-linear part of the
2479 kernel's virtual address map.
2483 config TEST_MEMCAT_P
2484 tristate "Test memcat_p() helper function"
2486 Test the memcat_p() helper for correctly merging two
2487 pointer arrays together.
2491 config TEST_LIVEPATCH
2492 tristate "Test livepatching"
2494 depends on DYNAMIC_DEBUG
2495 depends on LIVEPATCH
2498 Test kernel livepatching features for correctness. The tests will
2499 load test modules that will be livepatched in various scenarios.
2501 To run all the livepatching tests:
2503 make -C tools/testing/selftests TARGETS=livepatch run_tests
2505 Alternatively, individual tests may be invoked:
2507 tools/testing/selftests/livepatch/test-callbacks.sh
2508 tools/testing/selftests/livepatch/test-livepatch.sh
2509 tools/testing/selftests/livepatch/test-shadow-vars.sh
2514 tristate "Perform selftest on object aggreration manager"
2518 Enable this option to test object aggregation manager on boot
2522 config TEST_STACKINIT
2523 tristate "Test level of stack variable initialization"
2525 Test if the kernel is zero-initializing stack variables and
2526 padding. Coverage is controlled by compiler flags,
2527 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2528 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2533 tristate "Test heap/page initialization"
2535 Test if the kernel is zero-initializing heap and page allocations.
2536 This can be useful to test init_on_alloc and init_on_free features.
2541 tristate "Test HMM (Heterogeneous Memory Management)"
2542 depends on TRANSPARENT_HUGEPAGE
2543 depends on DEVICE_PRIVATE
2547 This is a pseudo device driver solely for testing HMM.
2548 Say M here if you want to build the HMM test module.
2549 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2553 config TEST_FREE_PAGES
2554 tristate "Test freeing pages"
2556 Test that a memory leak does not occur due to a race between
2557 freeing a block of pages and a speculative page reference.
2558 Loading this module is safe if your kernel has the bug fixed.
2559 If the bug is not fixed, it will leak gigabytes of memory and
2560 probably OOM your system.
2563 tristate "Test floating point operations in kernel space"
2564 depends on X86 && !KCOV_INSTRUMENT_ALL
2566 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2567 which will trigger a sequence of floating point operations. This is used
2568 for self-testing floating point control register setting in
2573 endif # RUNTIME_TESTING_MENU
2575 config ARCH_USE_MEMTEST
2578 An architecture should select this when it uses early_memtest()
2579 during boot process.
2583 depends on ARCH_USE_MEMTEST
2585 This option adds a kernel parameter 'memtest', which allows memtest
2586 to be set and executed.
2587 memtest=0, mean disabled; -- default
2588 memtest=1, mean do 1 test pattern;
2590 memtest=17, mean do 17 test patterns.
2591 If you are unsure how to answer this question, answer N.
2595 config HYPERV_TESTING
2596 bool "Microsoft Hyper-V driver testing"
2598 depends on HYPERV && DEBUG_FS
2600 Select this option to enable Hyper-V vmbus testing.
2602 endmenu # "Kernel Testing and Coverage"
2604 source "Documentation/Kconfig"
2606 endmenu # Kernel hacking
projects / linux-2.6-microblaze.git / blob