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 PAHOLE_HAS_ZEROSIZE_PERCPU_SUPPORT
317 def_bool $(success, test `$(PAHOLE) --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/'` -ge "122")
319 config DEBUG_INFO_BTF_MODULES
321 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
323 Generate compact split BTF type information for kernel modules.
326 bool "Provide GDB scripts for kernel debugging"
328 This creates the required links to GDB helper scripts in the
329 build directory. If you load vmlinux into gdb, the helper
330 scripts will be automatically imported by gdb as well, and
331 additional functions are available to analyze a Linux kernel
332 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
338 int "Warn for stack frames larger than"
340 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
341 default 1280 if (!64BIT && PARISC)
342 default 1024 if (!64BIT && !PARISC)
343 default 2048 if 64BIT
345 Tell gcc to warn at build time for stack frames larger than this.
346 Setting this too low will cause a lot of warnings.
347 Setting it to 0 disables the warning.
349 config STRIP_ASM_SYMS
350 bool "Strip assembler-generated symbols during link"
353 Strip internal assembler-generated symbols during a link (symbols
354 that look like '.Lxxx') so they don't pollute the output of
355 get_wchan() and suchlike.
358 bool "Generate readable assembler code"
359 depends on DEBUG_KERNEL
361 Disable some compiler optimizations that tend to generate human unreadable
362 assembler output. This may make the kernel slightly slower, but it helps
363 to keep kernel developers who have to stare a lot at assembler listings
366 config HEADERS_INSTALL
367 bool "Install uapi headers to usr/include"
370 This option will install uapi headers (headers exported to user-space)
371 into the usr/include directory for use during the kernel build.
372 This is unneeded for building the kernel itself, but needed for some
373 user-space program samples. It is also needed by some features such
374 as uapi header sanity checks.
376 config DEBUG_SECTION_MISMATCH
377 bool "Enable full Section mismatch analysis"
379 The section mismatch analysis checks if there are illegal
380 references from one section to another section.
381 During linktime or runtime, some sections are dropped;
382 any use of code/data previously in these sections would
383 most likely result in an oops.
384 In the code, functions and variables are annotated with
385 __init,, etc. (see the full list in include/linux/init.h),
386 which results in the code/data being placed in specific sections.
387 The section mismatch analysis is always performed after a full
388 kernel build, and enabling this option causes the following
389 additional step to occur:
390 - Add the option -fno-inline-functions-called-once to gcc commands.
391 When inlining a function annotated with __init in a non-init
392 function, we would lose the section information and thus
393 the analysis would not catch the illegal reference.
394 This option tells gcc to inline less (but it does result in
397 config SECTION_MISMATCH_WARN_ONLY
398 bool "Make section mismatch errors non-fatal"
401 If you say N here, the build process will fail if there are any
402 section mismatch, instead of just throwing warnings.
406 config DEBUG_FORCE_FUNCTION_ALIGN_32B
407 bool "Force all function address 32B aligned" if EXPERT
409 There are cases that a commit from one domain changes the function
410 address alignment of other domains, and cause magic performance
411 bump (regression or improvement). Enable this option will help to
412 verify if the bump is caused by function alignment changes, while
413 it will slightly increase the kernel size and affect icache usage.
415 It is mainly for debug and performance tuning use.
418 # Select this config option from the architecture Kconfig, if it
419 # is preferred to always offer frame pointers as a config
420 # option on the architecture (regardless of KERNEL_DEBUG):
422 config ARCH_WANT_FRAME_POINTERS
426 bool "Compile the kernel with frame pointers"
427 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
428 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
430 If you say Y here the resulting kernel image will be slightly
431 larger and slower, but it gives very useful debugging information
432 in case of kernel bugs. (precise oopses/stacktraces/warnings)
434 config STACK_VALIDATION
435 bool "Compile-time stack metadata validation"
436 depends on HAVE_STACK_VALIDATION
439 Add compile-time checks to validate stack metadata, including frame
440 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
441 that runtime stack traces are more reliable.
443 This is also a prerequisite for generation of ORC unwind data, which
444 is needed for CONFIG_UNWINDER_ORC.
446 For more information, see
447 tools/objtool/Documentation/stack-validation.txt.
449 config VMLINUX_VALIDATION
451 depends on STACK_VALIDATION && DEBUG_ENTRY && !PARAVIRT
455 bool "Generate vmlinux.map file when linking"
458 Selecting this option will pass "-Map=vmlinux.map" to ld
459 when linking vmlinux. That file can be useful for verifying
460 and debugging magic section games, and for seeing which
461 pieces of code get eliminated with
462 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
464 config DEBUG_FORCE_WEAK_PER_CPU
465 bool "Force weak per-cpu definitions"
466 depends on DEBUG_KERNEL
468 s390 and alpha require percpu variables in modules to be
469 defined weak to work around addressing range issue which
470 puts the following two restrictions on percpu variable
473 1. percpu symbols must be unique whether static or not
474 2. percpu variables can't be defined inside a function
476 To ensure that generic code follows the above rules, this
477 option forces all percpu variables to be defined as weak.
479 endmenu # "Compiler options"
481 menu "Generic Kernel Debugging Instruments"
484 bool "Magic SysRq key"
487 If you say Y here, you will have some control over the system even
488 if the system crashes for example during kernel debugging (e.g., you
489 will be able to flush the buffer cache to disk, reboot the system
490 immediately or dump some status information). This is accomplished
491 by pressing various keys while holding SysRq (Alt+PrintScreen). It
492 also works on a serial console (on PC hardware at least), if you
493 send a BREAK and then within 5 seconds a command keypress. The
494 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
495 Don't say Y unless you really know what this hack does.
497 config MAGIC_SYSRQ_DEFAULT_ENABLE
498 hex "Enable magic SysRq key functions by default"
499 depends on MAGIC_SYSRQ
502 Specifies which SysRq key functions are enabled by default.
503 This may be set to 1 or 0 to enable or disable them all, or
504 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
506 config MAGIC_SYSRQ_SERIAL
507 bool "Enable magic SysRq key over serial"
508 depends on MAGIC_SYSRQ
511 Many embedded boards have a disconnected TTL level serial which can
512 generate some garbage that can lead to spurious false sysrq detects.
513 This option allows you to decide whether you want to enable the
516 config MAGIC_SYSRQ_SERIAL_SEQUENCE
517 string "Char sequence that enables magic SysRq over serial"
518 depends on MAGIC_SYSRQ_SERIAL
521 Specifies a sequence of characters that can follow BREAK to enable
522 SysRq on a serial console.
524 If unsure, leave an empty string and the option will not be enabled.
527 bool "Debug Filesystem"
529 debugfs is a virtual file system that kernel developers use to put
530 debugging files into. Enable this option to be able to read and
531 write to these files.
533 For detailed documentation on the debugfs API, see
534 Documentation/filesystems/.
539 prompt "Debugfs default access"
541 default DEBUG_FS_ALLOW_ALL
543 This selects the default access restrictions for debugfs.
544 It can be overridden with kernel command line option
545 debugfs=[on,no-mount,off]. The restrictions apply for API access
546 and filesystem registration.
548 config DEBUG_FS_ALLOW_ALL
551 No restrictions apply. Both API and filesystem registration
552 is on. This is the normal default operation.
554 config DEBUG_FS_DISALLOW_MOUNT
555 bool "Do not register debugfs as filesystem"
557 The API is open but filesystem is not loaded. Clients can still do
558 their work and read with debug tools that do not need
561 config DEBUG_FS_ALLOW_NONE
564 Access is off. Clients get -PERM when trying to create nodes in
565 debugfs tree and debugfs is not registered as a filesystem.
566 Client can then back-off or continue without debugfs access.
570 source "lib/Kconfig.kgdb"
571 source "lib/Kconfig.ubsan"
572 source "lib/Kconfig.kcsan"
577 bool "Kernel debugging"
579 Say Y here if you are developing drivers or trying to debug and
580 identify kernel problems.
583 bool "Miscellaneous debug code"
585 depends on DEBUG_KERNEL
587 Say Y here if you need to enable miscellaneous debug code that should
588 be under a more specific debug option but isn't.
591 menu "Memory Debugging"
593 source "mm/Kconfig.debug"
596 bool "Debug object operations"
597 depends on DEBUG_KERNEL
599 If you say Y here, additional code will be inserted into the
600 kernel to track the life time of various objects and validate
601 the operations on those objects.
603 config DEBUG_OBJECTS_SELFTEST
604 bool "Debug objects selftest"
605 depends on DEBUG_OBJECTS
607 This enables the selftest of the object debug code.
609 config DEBUG_OBJECTS_FREE
610 bool "Debug objects in freed memory"
611 depends on DEBUG_OBJECTS
613 This enables checks whether a k/v free operation frees an area
614 which contains an object which has not been deactivated
615 properly. This can make kmalloc/kfree-intensive workloads
618 config DEBUG_OBJECTS_TIMERS
619 bool "Debug timer objects"
620 depends on DEBUG_OBJECTS
622 If you say Y here, additional code will be inserted into the
623 timer routines to track the life time of timer objects and
624 validate the timer operations.
626 config DEBUG_OBJECTS_WORK
627 bool "Debug work objects"
628 depends on DEBUG_OBJECTS
630 If you say Y here, additional code will be inserted into the
631 work queue routines to track the life time of work objects and
632 validate the work operations.
634 config DEBUG_OBJECTS_RCU_HEAD
635 bool "Debug RCU callbacks objects"
636 depends on DEBUG_OBJECTS
638 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
640 config DEBUG_OBJECTS_PERCPU_COUNTER
641 bool "Debug percpu counter objects"
642 depends on DEBUG_OBJECTS
644 If you say Y here, additional code will be inserted into the
645 percpu counter routines to track the life time of percpu counter
646 objects and validate the percpu counter operations.
648 config DEBUG_OBJECTS_ENABLE_DEFAULT
649 int "debug_objects bootup default value (0-1)"
652 depends on DEBUG_OBJECTS
654 Debug objects boot parameter default value
657 bool "Debug slab memory allocations"
658 depends on DEBUG_KERNEL && SLAB
660 Say Y here to have the kernel do limited verification on memory
661 allocation as well as poisoning memory on free to catch use of freed
662 memory. This can make kmalloc/kfree-intensive workloads much slower.
665 bool "SLUB debugging on by default"
666 depends on SLUB && SLUB_DEBUG
669 Boot with debugging on by default. SLUB boots by default with
670 the runtime debug capabilities switched off. Enabling this is
671 equivalent to specifying the "slub_debug" parameter on boot.
672 There is no support for more fine grained debug control like
673 possible with slub_debug=xxx. SLUB debugging may be switched
674 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
679 bool "Enable SLUB performance statistics"
680 depends on SLUB && SYSFS
682 SLUB statistics are useful to debug SLUBs allocation behavior in
683 order find ways to optimize the allocator. This should never be
684 enabled for production use since keeping statistics slows down
685 the allocator by a few percentage points. The slabinfo command
686 supports the determination of the most active slabs to figure
687 out which slabs are relevant to a particular load.
688 Try running: slabinfo -DA
690 config HAVE_DEBUG_KMEMLEAK
693 config DEBUG_KMEMLEAK
694 bool "Kernel memory leak detector"
695 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
697 select STACKTRACE if STACKTRACE_SUPPORT
701 Say Y here if you want to enable the memory leak
702 detector. The memory allocation/freeing is traced in a way
703 similar to the Boehm's conservative garbage collector, the
704 difference being that the orphan objects are not freed but
705 only shown in /sys/kernel/debug/kmemleak. Enabling this
706 feature will introduce an overhead to memory
707 allocations. See Documentation/dev-tools/kmemleak.rst for more
710 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
711 of finding leaks due to the slab objects poisoning.
713 In order to access the kmemleak file, debugfs needs to be
714 mounted (usually at /sys/kernel/debug).
716 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
717 int "Kmemleak memory pool size"
718 depends on DEBUG_KMEMLEAK
722 Kmemleak must track all the memory allocations to avoid
723 reporting false positives. Since memory may be allocated or
724 freed before kmemleak is fully initialised, use a static pool
725 of metadata objects to track such callbacks. After kmemleak is
726 fully initialised, this memory pool acts as an emergency one
727 if slab allocations fail.
729 config DEBUG_KMEMLEAK_TEST
730 tristate "Simple test for the kernel memory leak detector"
731 depends on DEBUG_KMEMLEAK && m
733 This option enables a module that explicitly leaks memory.
737 config DEBUG_KMEMLEAK_DEFAULT_OFF
738 bool "Default kmemleak to off"
739 depends on DEBUG_KMEMLEAK
741 Say Y here to disable kmemleak by default. It can then be enabled
742 on the command line via kmemleak=on.
744 config DEBUG_KMEMLEAK_AUTO_SCAN
745 bool "Enable kmemleak auto scan thread on boot up"
747 depends on DEBUG_KMEMLEAK
749 Depending on the cpu, kmemleak scan may be cpu intensive and can
750 stall user tasks at times. This option enables/disables automatic
751 kmemleak scan at boot up.
753 Say N here to disable kmemleak auto scan thread to stop automatic
754 scanning. Disabling this option disables automatic reporting of
759 config DEBUG_STACK_USAGE
760 bool "Stack utilization instrumentation"
761 depends on DEBUG_KERNEL && !IA64
763 Enables the display of the minimum amount of free stack which each
764 task has ever had available in the sysrq-T and sysrq-P debug output.
766 This option will slow down process creation somewhat.
768 config SCHED_STACK_END_CHECK
769 bool "Detect stack corruption on calls to schedule()"
770 depends on DEBUG_KERNEL
773 This option checks for a stack overrun on calls to schedule().
774 If the stack end location is found to be over written always panic as
775 the content of the corrupted region can no longer be trusted.
776 This is to ensure no erroneous behaviour occurs which could result in
777 data corruption or a sporadic crash at a later stage once the region
778 is examined. The runtime overhead introduced is minimal.
780 config ARCH_HAS_DEBUG_VM_PGTABLE
783 An architecture should select this when it can successfully
784 build and run DEBUG_VM_PGTABLE.
788 depends on DEBUG_KERNEL
790 Enable this to turn on extended checks in the virtual-memory system
791 that may impact performance.
795 config DEBUG_VM_VMACACHE
796 bool "Debug VMA caching"
799 Enable this to turn on VMA caching debug information. Doing so
800 can cause significant overhead, so only enable it in non-production
806 bool "Debug VM red-black trees"
809 Enable VM red-black tree debugging information and extra validations.
813 config DEBUG_VM_PGFLAGS
814 bool "Debug page-flags operations"
817 Enables extra validation on page flags operations.
821 config DEBUG_VM_PGTABLE
822 bool "Debug arch page table for semantics compliance"
824 depends on ARCH_HAS_DEBUG_VM_PGTABLE
825 default y if DEBUG_VM
827 This option provides a debug method which can be used to test
828 architecture page table helper functions on various platforms in
829 verifying if they comply with expected generic MM semantics. This
830 will help architecture code in making sure that any changes or
831 new additions of these helpers still conform to expected
832 semantics of the generic MM. Platforms will have to opt in for
833 this through ARCH_HAS_DEBUG_VM_PGTABLE.
837 config ARCH_HAS_DEBUG_VIRTUAL
841 bool "Debug VM translations"
842 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
844 Enable some costly sanity checks in virtual to page code. This can
845 catch mistakes with virt_to_page() and friends.
849 config DEBUG_NOMMU_REGIONS
850 bool "Debug the global anon/private NOMMU mapping region tree"
851 depends on DEBUG_KERNEL && !MMU
853 This option causes the global tree of anonymous and private mapping
854 regions to be regularly checked for invalid topology.
856 config DEBUG_MEMORY_INIT
857 bool "Debug memory initialisation" if EXPERT
860 Enable this for additional checks during memory initialisation.
861 The sanity checks verify aspects of the VM such as the memory model
862 and other information provided by the architecture. Verbose
863 information will be printed at KERN_DEBUG loglevel depending
864 on the mminit_loglevel= command-line option.
868 config MEMORY_NOTIFIER_ERROR_INJECT
869 tristate "Memory hotplug notifier error injection module"
870 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
872 This option provides the ability to inject artificial errors to
873 memory hotplug notifier chain callbacks. It is controlled through
874 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
876 If the notifier call chain should be failed with some events
877 notified, write the error code to "actions/<notifier event>/error".
879 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
881 # cd /sys/kernel/debug/notifier-error-inject/memory
882 # echo -12 > actions/MEM_GOING_OFFLINE/error
883 # echo offline > /sys/devices/system/memory/memoryXXX/state
884 bash: echo: write error: Cannot allocate memory
886 To compile this code as a module, choose M here: the module will
887 be called memory-notifier-error-inject.
891 config DEBUG_PER_CPU_MAPS
892 bool "Debug access to per_cpu maps"
893 depends on DEBUG_KERNEL
896 Say Y to verify that the per_cpu map being accessed has
897 been set up. This adds a fair amount of code to kernel memory
898 and decreases performance.
902 config DEBUG_KMAP_LOCAL
903 bool "Debug kmap_local temporary mappings"
904 depends on DEBUG_KERNEL && KMAP_LOCAL
906 This option enables additional error checking for the kmap_local
907 infrastructure. Disable for production use.
909 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
912 config DEBUG_KMAP_LOCAL_FORCE_MAP
913 bool "Enforce kmap_local temporary mappings"
914 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
916 select DEBUG_KMAP_LOCAL
918 This option enforces temporary mappings through the kmap_local
919 mechanism for non-highmem pages and on non-highmem systems.
920 Disable this for production systems!
923 bool "Highmem debugging"
924 depends on DEBUG_KERNEL && HIGHMEM
925 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
926 select DEBUG_KMAP_LOCAL
928 This option enables additional error checking for high memory
929 systems. Disable for production systems.
931 config HAVE_DEBUG_STACKOVERFLOW
934 config DEBUG_STACKOVERFLOW
935 bool "Check for stack overflows"
936 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
938 Say Y here if you want to check for overflows of kernel, IRQ
939 and exception stacks (if your architecture uses them). This
940 option will show detailed messages if free stack space drops
941 below a certain limit.
943 These kinds of bugs usually occur when call-chains in the
944 kernel get too deep, especially when interrupts are
947 Use this in cases where you see apparently random memory
948 corruption, especially if it appears in 'struct thread_info'
950 If in doubt, say "N".
952 source "lib/Kconfig.kasan"
953 source "lib/Kconfig.kfence"
955 endmenu # "Memory Debugging"
958 bool "Debug shared IRQ handlers"
959 depends on DEBUG_KERNEL
961 Enable this to generate a spurious interrupt just before a shared
962 interrupt handler is deregistered (generating one when registering
963 is currently disabled). Drivers need to handle this correctly. Some
964 don't and need to be caught.
966 menu "Debug Oops, Lockups and Hangs"
971 Say Y here to enable the kernel to panic when it oopses. This
972 has the same effect as setting oops=panic on the kernel command
975 This feature is useful to ensure that the kernel does not do
976 anything erroneous after an oops which could result in data
977 corruption or other issues.
981 config PANIC_ON_OOPS_VALUE
984 default 0 if !PANIC_ON_OOPS
985 default 1 if PANIC_ON_OOPS
991 Set the timeout value (in seconds) until a reboot occurs when
992 the kernel panics. If n = 0, then we wait forever. A timeout
993 value n > 0 will wait n seconds before rebooting, while a timeout
994 value n < 0 will reboot immediately.
996 config LOCKUP_DETECTOR
999 config SOFTLOCKUP_DETECTOR
1000 bool "Detect Soft Lockups"
1001 depends on DEBUG_KERNEL && !S390
1002 select LOCKUP_DETECTOR
1004 Say Y here to enable the kernel to act as a watchdog to detect
1007 Softlockups are bugs that cause the kernel to loop in kernel
1008 mode for more than 20 seconds, without giving other tasks a
1009 chance to run. The current stack trace is displayed upon
1010 detection and the system will stay locked up.
1012 config BOOTPARAM_SOFTLOCKUP_PANIC
1013 bool "Panic (Reboot) On Soft Lockups"
1014 depends on SOFTLOCKUP_DETECTOR
1016 Say Y here to enable the kernel to panic on "soft lockups",
1017 which are bugs that cause the kernel to loop in kernel
1018 mode for more than 20 seconds (configurable using the watchdog_thresh
1019 sysctl), without giving other tasks a chance to run.
1021 The panic can be used in combination with panic_timeout,
1022 to cause the system to reboot automatically after a
1023 lockup has been detected. This feature is useful for
1024 high-availability systems that have uptime guarantees and
1025 where a lockup must be resolved ASAP.
1029 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
1031 depends on SOFTLOCKUP_DETECTOR
1033 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
1034 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
1036 config HARDLOCKUP_DETECTOR_PERF
1038 select SOFTLOCKUP_DETECTOR
1041 # Enables a timestamp based low pass filter to compensate for perf based
1042 # hard lockup detection which runs too fast due to turbo modes.
1044 config HARDLOCKUP_CHECK_TIMESTAMP
1048 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1049 # lockup detector rather than the perf based detector.
1051 config HARDLOCKUP_DETECTOR
1052 bool "Detect Hard Lockups"
1053 depends on DEBUG_KERNEL && !S390
1054 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1055 select LOCKUP_DETECTOR
1056 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1057 select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH
1059 Say Y here to enable the kernel to act as a watchdog to detect
1062 Hardlockups are bugs that cause the CPU to loop in kernel mode
1063 for more than 10 seconds, without letting other interrupts have a
1064 chance to run. The current stack trace is displayed upon detection
1065 and the system will stay locked up.
1067 config BOOTPARAM_HARDLOCKUP_PANIC
1068 bool "Panic (Reboot) On Hard Lockups"
1069 depends on HARDLOCKUP_DETECTOR
1071 Say Y here to enable the kernel to panic on "hard lockups",
1072 which are bugs that cause the kernel to loop in kernel
1073 mode with interrupts disabled for more than 10 seconds (configurable
1074 using the watchdog_thresh sysctl).
1078 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
1080 depends on HARDLOCKUP_DETECTOR
1082 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
1083 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
1085 config DETECT_HUNG_TASK
1086 bool "Detect Hung Tasks"
1087 depends on DEBUG_KERNEL
1088 default SOFTLOCKUP_DETECTOR
1090 Say Y here to enable the kernel to detect "hung tasks",
1091 which are bugs that cause the task to be stuck in
1092 uninterruptible "D" state indefinitely.
1094 When a hung task is detected, the kernel will print the
1095 current stack trace (which you should report), but the
1096 task will stay in uninterruptible state. If lockdep is
1097 enabled then all held locks will also be reported. This
1098 feature has negligible overhead.
1100 config DEFAULT_HUNG_TASK_TIMEOUT
1101 int "Default timeout for hung task detection (in seconds)"
1102 depends on DETECT_HUNG_TASK
1105 This option controls the default timeout (in seconds) used
1106 to determine when a task has become non-responsive and should
1109 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1110 sysctl or by writing a value to
1111 /proc/sys/kernel/hung_task_timeout_secs.
1113 A timeout of 0 disables the check. The default is two minutes.
1114 Keeping the default should be fine in most cases.
1116 config BOOTPARAM_HUNG_TASK_PANIC
1117 bool "Panic (Reboot) On Hung Tasks"
1118 depends on DETECT_HUNG_TASK
1120 Say Y here to enable the kernel to panic on "hung tasks",
1121 which are bugs that cause the kernel to leave a task stuck
1122 in uninterruptible "D" state.
1124 The panic can be used in combination with panic_timeout,
1125 to cause the system to reboot automatically after a
1126 hung task has been detected. This feature is useful for
1127 high-availability systems that have uptime guarantees and
1128 where a hung tasks must be resolved ASAP.
1132 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
1134 depends on DETECT_HUNG_TASK
1136 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
1137 default 1 if BOOTPARAM_HUNG_TASK_PANIC
1140 bool "Detect Workqueue Stalls"
1141 depends on DEBUG_KERNEL
1143 Say Y here to enable stall detection on workqueues. If a
1144 worker pool doesn't make forward progress on a pending work
1145 item for over a given amount of time, 30s by default, a
1146 warning message is printed along with dump of workqueue
1147 state. This can be configured through kernel parameter
1148 "workqueue.watchdog_thresh" and its sysfs counterpart.
1151 tristate "Test module to generate lockups"
1154 This builds the "test_lockup" module that helps to make sure
1155 that watchdogs and lockup detectors are working properly.
1157 Depending on module parameters it could emulate soft or hard
1158 lockup, "hung task", or locking arbitrary lock for a long time.
1159 Also it could generate series of lockups with cooling-down periods.
1163 endmenu # "Debug lockups and hangs"
1165 menu "Scheduler Debugging"
1168 bool "Collect scheduler debugging info"
1169 depends on DEBUG_KERNEL && PROC_FS
1172 If you say Y here, the /proc/sched_debug file will be provided
1173 that can help debug the scheduler. The runtime overhead of this
1181 bool "Collect scheduler statistics"
1182 depends on DEBUG_KERNEL && PROC_FS
1185 If you say Y here, additional code will be inserted into the
1186 scheduler and related routines to collect statistics about
1187 scheduler behavior and provide them in /proc/schedstat. These
1188 stats may be useful for both tuning and debugging the scheduler
1189 If you aren't debugging the scheduler or trying to tune a specific
1190 application, you can say N to avoid the very slight overhead
1195 config DEBUG_TIMEKEEPING
1196 bool "Enable extra timekeeping sanity checking"
1198 This option will enable additional timekeeping sanity checks
1199 which may be helpful when diagnosing issues where timekeeping
1200 problems are suspected.
1202 This may include checks in the timekeeping hotpaths, so this
1203 option may have a (very small) performance impact to some
1208 config DEBUG_PREEMPT
1209 bool "Debug preemptible kernel"
1210 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1213 If you say Y here then the kernel will use a debug variant of the
1214 commonly used smp_processor_id() function and will print warnings
1215 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1216 will detect preemption count underflows.
1218 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1220 config LOCK_DEBUGGING_SUPPORT
1222 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1225 config PROVE_LOCKING
1226 bool "Lock debugging: prove locking correctness"
1227 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1229 select DEBUG_SPINLOCK
1230 select DEBUG_MUTEXES
1231 select DEBUG_RT_MUTEXES if RT_MUTEXES
1233 select DEBUG_WW_MUTEX_SLOWPATH
1234 select DEBUG_LOCK_ALLOC
1235 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1236 select TRACE_IRQFLAGS
1239 This feature enables the kernel to prove that all locking
1240 that occurs in the kernel runtime is mathematically
1241 correct: that under no circumstance could an arbitrary (and
1242 not yet triggered) combination of observed locking
1243 sequences (on an arbitrary number of CPUs, running an
1244 arbitrary number of tasks and interrupt contexts) cause a
1247 In short, this feature enables the kernel to report locking
1248 related deadlocks before they actually occur.
1250 The proof does not depend on how hard and complex a
1251 deadlock scenario would be to trigger: how many
1252 participant CPUs, tasks and irq-contexts would be needed
1253 for it to trigger. The proof also does not depend on
1254 timing: if a race and a resulting deadlock is possible
1255 theoretically (no matter how unlikely the race scenario
1256 is), it will be proven so and will immediately be
1257 reported by the kernel (once the event is observed that
1258 makes the deadlock theoretically possible).
1260 If a deadlock is impossible (i.e. the locking rules, as
1261 observed by the kernel, are mathematically correct), the
1262 kernel reports nothing.
1264 NOTE: this feature can also be enabled for rwlocks, mutexes
1265 and rwsems - in which case all dependencies between these
1266 different locking variants are observed and mapped too, and
1267 the proof of observed correctness is also maintained for an
1268 arbitrary combination of these separate locking variants.
1270 For more details, see Documentation/locking/lockdep-design.rst.
1272 config PROVE_RAW_LOCK_NESTING
1273 bool "Enable raw_spinlock - spinlock nesting checks"
1274 depends on PROVE_LOCKING
1277 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1278 that the lock nesting rules for PREEMPT_RT enabled kernels are
1281 NOTE: There are known nesting problems. So if you enable this
1282 option expect lockdep splats until these problems have been fully
1283 addressed which is work in progress. This config switch allows to
1284 identify and analyze these problems. It will be removed and the
1285 check permanentely enabled once the main issues have been fixed.
1287 If unsure, select N.
1290 bool "Lock usage statistics"
1291 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1293 select DEBUG_SPINLOCK
1294 select DEBUG_MUTEXES
1295 select DEBUG_RT_MUTEXES if RT_MUTEXES
1296 select DEBUG_LOCK_ALLOC
1299 This feature enables tracking lock contention points
1301 For more details, see Documentation/locking/lockstat.rst
1303 This also enables lock events required by "perf lock",
1305 If you want to use "perf lock", you also need to turn on
1306 CONFIG_EVENT_TRACING.
1308 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1309 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1311 config DEBUG_RT_MUTEXES
1312 bool "RT Mutex debugging, deadlock detection"
1313 depends on DEBUG_KERNEL && RT_MUTEXES
1315 This allows rt mutex semantics violations and rt mutex related
1316 deadlocks (lockups) to be detected and reported automatically.
1318 config DEBUG_SPINLOCK
1319 bool "Spinlock and rw-lock debugging: basic checks"
1320 depends on DEBUG_KERNEL
1321 select UNINLINE_SPIN_UNLOCK
1323 Say Y here and build SMP to catch missing spinlock initialization
1324 and certain other kinds of spinlock errors commonly made. This is
1325 best used in conjunction with the NMI watchdog so that spinlock
1326 deadlocks are also debuggable.
1328 config DEBUG_MUTEXES
1329 bool "Mutex debugging: basic checks"
1330 depends on DEBUG_KERNEL
1332 This feature allows mutex semantics violations to be detected and
1335 config DEBUG_WW_MUTEX_SLOWPATH
1336 bool "Wait/wound mutex debugging: Slowpath testing"
1337 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1338 select DEBUG_LOCK_ALLOC
1339 select DEBUG_SPINLOCK
1340 select DEBUG_MUTEXES
1342 This feature enables slowpath testing for w/w mutex users by
1343 injecting additional -EDEADLK wound/backoff cases. Together with
1344 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1345 will test all possible w/w mutex interface abuse with the
1346 exception of simply not acquiring all the required locks.
1347 Note that this feature can introduce significant overhead, so
1348 it really should not be enabled in a production or distro kernel,
1349 even a debug kernel. If you are a driver writer, enable it. If
1350 you are a distro, do not.
1353 bool "RW Semaphore debugging: basic checks"
1354 depends on DEBUG_KERNEL
1356 This debugging feature allows mismatched rw semaphore locks
1357 and unlocks to be detected and reported.
1359 config DEBUG_LOCK_ALLOC
1360 bool "Lock debugging: detect incorrect freeing of live locks"
1361 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1362 select DEBUG_SPINLOCK
1363 select DEBUG_MUTEXES
1364 select DEBUG_RT_MUTEXES if RT_MUTEXES
1367 This feature will check whether any held lock (spinlock, rwlock,
1368 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1369 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1370 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1371 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1372 held during task exit.
1376 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1381 config LOCKDEP_SMALL
1385 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1386 depends on LOCKDEP && !LOCKDEP_SMALL
1390 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1392 config LOCKDEP_CHAINS_BITS
1393 int "Bitsize for MAX_LOCKDEP_CHAINS"
1394 depends on LOCKDEP && !LOCKDEP_SMALL
1398 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1400 config LOCKDEP_STACK_TRACE_BITS
1401 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1402 depends on LOCKDEP && !LOCKDEP_SMALL
1406 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1408 config LOCKDEP_STACK_TRACE_HASH_BITS
1409 int "Bitsize for STACK_TRACE_HASH_SIZE"
1410 depends on LOCKDEP && !LOCKDEP_SMALL
1414 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1416 config LOCKDEP_CIRCULAR_QUEUE_BITS
1417 int "Bitsize for elements in circular_queue struct"
1422 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1424 config DEBUG_LOCKDEP
1425 bool "Lock dependency engine debugging"
1426 depends on DEBUG_KERNEL && LOCKDEP
1427 select DEBUG_IRQFLAGS
1429 If you say Y here, the lock dependency engine will do
1430 additional runtime checks to debug itself, at the price
1431 of more runtime overhead.
1433 config DEBUG_ATOMIC_SLEEP
1434 bool "Sleep inside atomic section checking"
1435 select PREEMPT_COUNT
1436 depends on DEBUG_KERNEL
1437 depends on !ARCH_NO_PREEMPT
1439 If you say Y here, various routines which may sleep will become very
1440 noisy if they are called inside atomic sections: when a spinlock is
1441 held, inside an rcu read side critical section, inside preempt disabled
1442 sections, inside an interrupt, etc...
1444 config DEBUG_LOCKING_API_SELFTESTS
1445 bool "Locking API boot-time self-tests"
1446 depends on DEBUG_KERNEL
1448 Say Y here if you want the kernel to run a short self-test during
1449 bootup. The self-test checks whether common types of locking bugs
1450 are detected by debugging mechanisms or not. (if you disable
1451 lock debugging then those bugs wont be detected of course.)
1452 The following locking APIs are covered: spinlocks, rwlocks,
1455 config LOCK_TORTURE_TEST
1456 tristate "torture tests for locking"
1457 depends on DEBUG_KERNEL
1460 This option provides a kernel module that runs torture tests
1461 on kernel locking primitives. The kernel module may be built
1462 after the fact on the running kernel to be tested, if desired.
1464 Say Y here if you want kernel locking-primitive torture tests
1465 to be built into the kernel.
1466 Say M if you want these torture tests to build as a module.
1467 Say N if you are unsure.
1469 config WW_MUTEX_SELFTEST
1470 tristate "Wait/wound mutex selftests"
1472 This option provides a kernel module that runs tests on the
1473 on the struct ww_mutex locking API.
1475 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1476 with this test harness.
1478 Say M if you want these self tests to build as a module.
1479 Say N if you are unsure.
1481 config SCF_TORTURE_TEST
1482 tristate "torture tests for smp_call_function*()"
1483 depends on DEBUG_KERNEL
1486 This option provides a kernel module that runs torture tests
1487 on the smp_call_function() family of primitives. The kernel
1488 module may be built after the fact on the running kernel to
1489 be tested, if desired.
1491 config CSD_LOCK_WAIT_DEBUG
1492 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1493 depends on DEBUG_KERNEL
1497 This option enables debug prints when CPUs are slow to respond
1498 to the smp_call_function*() IPI wrappers. These debug prints
1499 include the IPI handler function currently executing (if any)
1500 and relevant stack traces.
1502 endmenu # lock debugging
1504 config TRACE_IRQFLAGS
1505 depends on TRACE_IRQFLAGS_SUPPORT
1508 Enables hooks to interrupt enabling and disabling for
1509 either tracing or lock debugging.
1511 config TRACE_IRQFLAGS_NMI
1513 depends on TRACE_IRQFLAGS
1514 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1516 config DEBUG_IRQFLAGS
1517 bool "Debug IRQ flag manipulation"
1519 Enables checks for potentially unsafe enabling or disabling of
1520 interrupts, such as calling raw_local_irq_restore() when interrupts
1524 bool "Stack backtrace support"
1525 depends on STACKTRACE_SUPPORT
1527 This option causes the kernel to create a /proc/pid/stack for
1528 every process, showing its current stack trace.
1529 It is also used by various kernel debugging features that require
1530 stack trace generation.
1532 config WARN_ALL_UNSEEDED_RANDOM
1533 bool "Warn for all uses of unseeded randomness"
1536 Some parts of the kernel contain bugs relating to their use of
1537 cryptographically secure random numbers before it's actually possible
1538 to generate those numbers securely. This setting ensures that these
1539 flaws don't go unnoticed, by enabling a message, should this ever
1540 occur. This will allow people with obscure setups to know when things
1541 are going wrong, so that they might contact developers about fixing
1544 Unfortunately, on some models of some architectures getting
1545 a fully seeded CRNG is extremely difficult, and so this can
1546 result in dmesg getting spammed for a surprisingly long
1547 time. This is really bad from a security perspective, and
1548 so architecture maintainers really need to do what they can
1549 to get the CRNG seeded sooner after the system is booted.
1550 However, since users cannot do anything actionable to
1551 address this, by default the kernel will issue only a single
1552 warning for the first use of unseeded randomness.
1554 Say Y here if you want to receive warnings for all uses of
1555 unseeded randomness. This will be of use primarily for
1556 those developers interested in improving the security of
1557 Linux kernels running on their architecture (or
1560 config DEBUG_KOBJECT
1561 bool "kobject debugging"
1562 depends on DEBUG_KERNEL
1564 If you say Y here, some extra kobject debugging messages will be sent
1567 config DEBUG_KOBJECT_RELEASE
1568 bool "kobject release debugging"
1569 depends on DEBUG_OBJECTS_TIMERS
1571 kobjects are reference counted objects. This means that their
1572 last reference count put is not predictable, and the kobject can
1573 live on past the point at which a driver decides to drop it's
1574 initial reference to the kobject gained on allocation. An
1575 example of this would be a struct device which has just been
1578 However, some buggy drivers assume that after such an operation,
1579 the memory backing the kobject can be immediately freed. This
1580 goes completely against the principles of a refcounted object.
1582 If you say Y here, the kernel will delay the release of kobjects
1583 on the last reference count to improve the visibility of this
1584 kind of kobject release bug.
1586 config HAVE_DEBUG_BUGVERBOSE
1589 menu "Debug kernel data structures"
1592 bool "Debug linked list manipulation"
1593 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1595 Enable this to turn on extended checks in the linked-list
1601 bool "Debug priority linked list manipulation"
1602 depends on DEBUG_KERNEL
1604 Enable this to turn on extended checks in the priority-ordered
1605 linked-list (plist) walking routines. This checks the entire
1606 list multiple times during each manipulation.
1611 bool "Debug SG table operations"
1612 depends on DEBUG_KERNEL
1614 Enable this to turn on checks on scatter-gather tables. This can
1615 help find problems with drivers that do not properly initialize
1620 config DEBUG_NOTIFIERS
1621 bool "Debug notifier call chains"
1622 depends on DEBUG_KERNEL
1624 Enable this to turn on sanity checking for notifier call chains.
1625 This is most useful for kernel developers to make sure that
1626 modules properly unregister themselves from notifier chains.
1627 This is a relatively cheap check but if you care about maximum
1630 config BUG_ON_DATA_CORRUPTION
1631 bool "Trigger a BUG when data corruption is detected"
1634 Select this option if the kernel should BUG when it encounters
1635 data corruption in kernel memory structures when they get checked
1642 config DEBUG_CREDENTIALS
1643 bool "Debug credential management"
1644 depends on DEBUG_KERNEL
1646 Enable this to turn on some debug checking for credential
1647 management. The additional code keeps track of the number of
1648 pointers from task_structs to any given cred struct, and checks to
1649 see that this number never exceeds the usage count of the cred
1652 Furthermore, if SELinux is enabled, this also checks that the
1653 security pointer in the cred struct is never seen to be invalid.
1657 source "kernel/rcu/Kconfig.debug"
1659 config DEBUG_WQ_FORCE_RR_CPU
1660 bool "Force round-robin CPU selection for unbound work items"
1661 depends on DEBUG_KERNEL
1664 Workqueue used to implicitly guarantee that work items queued
1665 without explicit CPU specified are put on the local CPU. This
1666 guarantee is no longer true and while local CPU is still
1667 preferred work items may be put on foreign CPUs. Kernel
1668 parameter "workqueue.debug_force_rr_cpu" is added to force
1669 round-robin CPU selection to flush out usages which depend on the
1670 now broken guarantee. This config option enables the debug
1671 feature by default. When enabled, memory and cache locality will
1674 config DEBUG_BLOCK_EXT_DEVT
1675 bool "Force extended block device numbers and spread them"
1676 depends on DEBUG_KERNEL
1680 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1681 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1682 YOU ARE DOING. Distros, please enable this and fix whatever
1685 Conventionally, block device numbers are allocated from
1686 predetermined contiguous area. However, extended block area
1687 may introduce non-contiguous block device numbers. This
1688 option forces most block device numbers to be allocated from
1689 the extended space and spreads them to discover kernel or
1690 userland code paths which assume predetermined contiguous
1691 device number allocation.
1693 Note that turning on this debug option shuffles all the
1694 device numbers for all IDE and SCSI devices including libata
1695 ones, so root partition specified using device number
1696 directly (via rdev or root=MAJ:MIN) won't work anymore.
1697 Textual device names (root=/dev/sdXn) will continue to work.
1699 Say N if you are unsure.
1701 config CPU_HOTPLUG_STATE_CONTROL
1702 bool "Enable CPU hotplug state control"
1703 depends on DEBUG_KERNEL
1704 depends on HOTPLUG_CPU
1707 Allows to write steps between "offline" and "online" to the CPUs
1708 sysfs target file so states can be stepped granular. This is a debug
1709 option for now as the hotplug machinery cannot be stopped and
1710 restarted at arbitrary points yet.
1712 Say N if your are unsure.
1715 bool "Latency measuring infrastructure"
1716 depends on DEBUG_KERNEL
1717 depends on STACKTRACE_SUPPORT
1719 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1725 Enable this option if you want to use the LatencyTOP tool
1726 to find out which userspace is blocking on what kernel operations.
1728 source "kernel/trace/Kconfig"
1730 config PROVIDE_OHCI1394_DMA_INIT
1731 bool "Remote debugging over FireWire early on boot"
1732 depends on PCI && X86
1734 If you want to debug problems which hang or crash the kernel early
1735 on boot and the crashing machine has a FireWire port, you can use
1736 this feature to remotely access the memory of the crashed machine
1737 over FireWire. This employs remote DMA as part of the OHCI1394
1738 specification which is now the standard for FireWire controllers.
1740 With remote DMA, you can monitor the printk buffer remotely using
1741 firescope and access all memory below 4GB using fireproxy from gdb.
1742 Even controlling a kernel debugger is possible using remote DMA.
1746 If ohci1394_dma=early is used as boot parameter, it will initialize
1747 all OHCI1394 controllers which are found in the PCI config space.
1749 As all changes to the FireWire bus such as enabling and disabling
1750 devices cause a bus reset and thereby disable remote DMA for all
1751 devices, be sure to have the cable plugged and FireWire enabled on
1752 the debugging host before booting the debug target for debugging.
1754 This code (~1k) is freed after boot. By then, the firewire stack
1755 in charge of the OHCI-1394 controllers should be used instead.
1757 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1759 source "samples/Kconfig"
1761 config ARCH_HAS_DEVMEM_IS_ALLOWED
1764 config STRICT_DEVMEM
1765 bool "Filter access to /dev/mem"
1766 depends on MMU && DEVMEM
1767 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1768 default y if PPC || X86 || ARM64
1770 If this option is disabled, you allow userspace (root) access to all
1771 of memory, including kernel and userspace memory. Accidental
1772 access to this is obviously disastrous, but specific access can
1773 be used by people debugging the kernel. Note that with PAT support
1774 enabled, even in this case there are restrictions on /dev/mem
1775 use due to the cache aliasing requirements.
1777 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1778 file only allows userspace access to PCI space and the BIOS code and
1779 data regions. This is sufficient for dosemu and X and all common
1784 config IO_STRICT_DEVMEM
1785 bool "Filter I/O access to /dev/mem"
1786 depends on STRICT_DEVMEM
1788 If this option is disabled, you allow userspace (root) access to all
1789 io-memory regardless of whether a driver is actively using that
1790 range. Accidental access to this is obviously disastrous, but
1791 specific access can be used by people debugging kernel drivers.
1793 If this option is switched on, the /dev/mem file only allows
1794 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1795 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1796 if the driver using a given range cannot be disabled.
1800 menu "$(SRCARCH) Debugging"
1802 source "arch/$(SRCARCH)/Kconfig.debug"
1806 menu "Kernel Testing and Coverage"
1808 source "lib/kunit/Kconfig"
1810 config NOTIFIER_ERROR_INJECTION
1811 tristate "Notifier error injection"
1812 depends on DEBUG_KERNEL
1815 This option provides the ability to inject artificial errors to
1816 specified notifier chain callbacks. It is useful to test the error
1817 handling of notifier call chain failures.
1821 config PM_NOTIFIER_ERROR_INJECT
1822 tristate "PM notifier error injection module"
1823 depends on PM && NOTIFIER_ERROR_INJECTION
1824 default m if PM_DEBUG
1826 This option provides the ability to inject artificial errors to
1827 PM notifier chain callbacks. It is controlled through debugfs
1828 interface /sys/kernel/debug/notifier-error-inject/pm
1830 If the notifier call chain should be failed with some events
1831 notified, write the error code to "actions/<notifier event>/error".
1833 Example: Inject PM suspend error (-12 = -ENOMEM)
1835 # cd /sys/kernel/debug/notifier-error-inject/pm/
1836 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1837 # echo mem > /sys/power/state
1838 bash: echo: write error: Cannot allocate memory
1840 To compile this code as a module, choose M here: the module will
1841 be called pm-notifier-error-inject.
1845 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1846 tristate "OF reconfig notifier error injection module"
1847 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1849 This option provides the ability to inject artificial errors to
1850 OF reconfig notifier chain callbacks. It is controlled
1851 through debugfs interface under
1852 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1854 If the notifier call chain should be failed with some events
1855 notified, write the error code to "actions/<notifier event>/error".
1857 To compile this code as a module, choose M here: the module will
1858 be called of-reconfig-notifier-error-inject.
1862 config NETDEV_NOTIFIER_ERROR_INJECT
1863 tristate "Netdev notifier error injection module"
1864 depends on NET && NOTIFIER_ERROR_INJECTION
1866 This option provides the ability to inject artificial errors to
1867 netdevice notifier chain callbacks. It is controlled through debugfs
1868 interface /sys/kernel/debug/notifier-error-inject/netdev
1870 If the notifier call chain should be failed with some events
1871 notified, write the error code to "actions/<notifier event>/error".
1873 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1875 # cd /sys/kernel/debug/notifier-error-inject/netdev
1876 # echo -22 > actions/NETDEV_CHANGEMTU/error
1877 # ip link set eth0 mtu 1024
1878 RTNETLINK answers: Invalid argument
1880 To compile this code as a module, choose M here: the module will
1881 be called netdev-notifier-error-inject.
1885 config FUNCTION_ERROR_INJECTION
1887 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1889 config FAULT_INJECTION
1890 bool "Fault-injection framework"
1891 depends on DEBUG_KERNEL
1893 Provide fault-injection framework.
1894 For more details, see Documentation/fault-injection/.
1897 bool "Fault-injection capability for kmalloc"
1898 depends on FAULT_INJECTION
1899 depends on SLAB || SLUB
1901 Provide fault-injection capability for kmalloc.
1903 config FAIL_PAGE_ALLOC
1904 bool "Fault-injection capability for alloc_pages()"
1905 depends on FAULT_INJECTION
1907 Provide fault-injection capability for alloc_pages().
1909 config FAULT_INJECTION_USERCOPY
1910 bool "Fault injection capability for usercopy functions"
1911 depends on FAULT_INJECTION
1913 Provides fault-injection capability to inject failures
1914 in usercopy functions (copy_from_user(), get_user(), ...).
1916 config FAIL_MAKE_REQUEST
1917 bool "Fault-injection capability for disk IO"
1918 depends on FAULT_INJECTION && BLOCK
1920 Provide fault-injection capability for disk IO.
1922 config FAIL_IO_TIMEOUT
1923 bool "Fault-injection capability for faking disk interrupts"
1924 depends on FAULT_INJECTION && BLOCK
1926 Provide fault-injection capability on end IO handling. This
1927 will make the block layer "forget" an interrupt as configured,
1928 thus exercising the error handling.
1930 Only works with drivers that use the generic timeout handling,
1931 for others it wont do anything.
1934 bool "Fault-injection capability for futexes"
1936 depends on FAULT_INJECTION && FUTEX
1938 Provide fault-injection capability for futexes.
1940 config FAULT_INJECTION_DEBUG_FS
1941 bool "Debugfs entries for fault-injection capabilities"
1942 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1944 Enable configuration of fault-injection capabilities via debugfs.
1946 config FAIL_FUNCTION
1947 bool "Fault-injection capability for functions"
1948 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1950 Provide function-based fault-injection capability.
1951 This will allow you to override a specific function with a return
1952 with given return value. As a result, function caller will see
1953 an error value and have to handle it. This is useful to test the
1954 error handling in various subsystems.
1956 config FAIL_MMC_REQUEST
1957 bool "Fault-injection capability for MMC IO"
1958 depends on FAULT_INJECTION_DEBUG_FS && MMC
1960 Provide fault-injection capability for MMC IO.
1961 This will make the mmc core return data errors. This is
1962 useful to test the error handling in the mmc block device
1963 and to test how the mmc host driver handles retries from
1966 config FAULT_INJECTION_STACKTRACE_FILTER
1967 bool "stacktrace filter for fault-injection capabilities"
1968 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1971 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1973 Provide stacktrace filter for fault-injection capabilities
1975 config ARCH_HAS_KCOV
1978 An architecture should select this when it can successfully
1979 build and run with CONFIG_KCOV. This typically requires
1980 disabling instrumentation for some early boot code.
1982 config CC_HAS_SANCOV_TRACE_PC
1983 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1987 bool "Code coverage for fuzzing"
1988 depends on ARCH_HAS_KCOV
1989 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1991 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1993 KCOV exposes kernel code coverage information in a form suitable
1994 for coverage-guided fuzzing (randomized testing).
1996 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1997 different machines and across reboots. If you need stable PC values,
1998 disable RANDOMIZE_BASE.
2000 For more details, see Documentation/dev-tools/kcov.rst.
2002 config KCOV_ENABLE_COMPARISONS
2003 bool "Enable comparison operands collection by KCOV"
2005 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2007 KCOV also exposes operands of every comparison in the instrumented
2008 code along with operand sizes and PCs of the comparison instructions.
2009 These operands can be used by fuzzing engines to improve the quality
2010 of fuzzing coverage.
2012 config KCOV_INSTRUMENT_ALL
2013 bool "Instrument all code by default"
2017 If you are doing generic system call fuzzing (like e.g. syzkaller),
2018 then you will want to instrument the whole kernel and you should
2019 say y here. If you are doing more targeted fuzzing (like e.g.
2020 filesystem fuzzing with AFL) then you will want to enable coverage
2021 for more specific subsets of files, and should say n here.
2023 config KCOV_IRQ_AREA_SIZE
2024 hex "Size of interrupt coverage collection area in words"
2028 KCOV uses preallocated per-cpu areas to collect coverage from
2029 soft interrupts. This specifies the size of those areas in the
2030 number of unsigned long words.
2032 menuconfig RUNTIME_TESTING_MENU
2033 bool "Runtime Testing"
2036 if RUNTIME_TESTING_MENU
2039 tristate "Linux Kernel Dump Test Tool Module"
2042 This module enables testing of the different dumping mechanisms by
2043 inducing system failures at predefined crash points.
2044 If you don't need it: say N
2045 Choose M here to compile this code as a module. The module will be
2048 Documentation on how to use the module can be found in
2049 Documentation/fault-injection/provoke-crashes.rst
2051 config TEST_LIST_SORT
2052 tristate "Linked list sorting test"
2053 depends on DEBUG_KERNEL || m
2055 Enable this to turn on 'list_sort()' function test. This test is
2056 executed only once during system boot (so affects only boot time),
2057 or at module load time.
2061 config TEST_MIN_HEAP
2062 tristate "Min heap test"
2063 depends on DEBUG_KERNEL || m
2065 Enable this to turn on min heap function tests. This test is
2066 executed only once during system boot (so affects only boot time),
2067 or at module load time.
2072 tristate "Array-based sort test"
2073 depends on DEBUG_KERNEL || m
2075 This option enables the self-test function of 'sort()' at boot,
2076 or at module load time.
2081 tristate "64bit/32bit division and modulo test"
2082 depends on DEBUG_KERNEL || m
2084 Enable this to turn on 'do_div()' function test. This test is
2085 executed only once during system boot (so affects only boot time),
2086 or at module load time.
2090 config KPROBES_SANITY_TEST
2091 bool "Kprobes sanity tests"
2092 depends on DEBUG_KERNEL
2095 This option provides for testing basic kprobes functionality on
2096 boot. Samples of kprobe and kretprobe are inserted and
2097 verified for functionality.
2099 Say N if you are unsure.
2101 config BACKTRACE_SELF_TEST
2102 tristate "Self test for the backtrace code"
2103 depends on DEBUG_KERNEL
2105 This option provides a kernel module that can be used to test
2106 the kernel stack backtrace code. This option is not useful
2107 for distributions or general kernels, but only for kernel
2108 developers working on architecture code.
2110 Note that if you want to also test saved backtraces, you will
2111 have to enable STACKTRACE as well.
2113 Say N if you are unsure.
2116 tristate "Red-Black tree test"
2117 depends on DEBUG_KERNEL
2119 A benchmark measuring the performance of the rbtree library.
2120 Also includes rbtree invariant checks.
2122 config REED_SOLOMON_TEST
2123 tristate "Reed-Solomon library test"
2124 depends on DEBUG_KERNEL || m
2126 select REED_SOLOMON_ENC16
2127 select REED_SOLOMON_DEC16
2129 This option enables the self-test function of rslib at boot,
2130 or at module load time.
2134 config INTERVAL_TREE_TEST
2135 tristate "Interval tree test"
2136 depends on DEBUG_KERNEL
2137 select INTERVAL_TREE
2139 A benchmark measuring the performance of the interval tree library
2142 tristate "Per cpu operations test"
2143 depends on m && DEBUG_KERNEL
2145 Enable this option to build test module which validates per-cpu
2150 config ATOMIC64_SELFTEST
2151 tristate "Perform an atomic64_t self-test"
2153 Enable this option to test the atomic64_t functions at boot or
2154 at module load time.
2158 config ASYNC_RAID6_TEST
2159 tristate "Self test for hardware accelerated raid6 recovery"
2160 depends on ASYNC_RAID6_RECOV
2163 This is a one-shot self test that permutes through the
2164 recovery of all the possible two disk failure scenarios for a
2165 N-disk array. Recovery is performed with the asynchronous
2166 raid6 recovery routines, and will optionally use an offload
2167 engine if one is available.
2172 tristate "Test functions located in the hexdump module at runtime"
2174 config TEST_STRING_HELPERS
2175 tristate "Test functions located in the string_helpers module at runtime"
2178 tristate "Test strscpy*() family of functions at runtime"
2181 tristate "Test kstrto*() family of functions at runtime"
2184 tristate "Test printf() family of functions at runtime"
2187 tristate "Test scanf() family of functions at runtime"
2190 tristate "Test bitmap_*() family of functions at runtime"
2192 Enable this option to test the bitmap functions at boot.
2197 tristate "Test functions located in the uuid module at runtime"
2200 tristate "Test the XArray code at runtime"
2202 config TEST_OVERFLOW
2203 tristate "Test check_*_overflow() functions at runtime"
2205 config TEST_RHASHTABLE
2206 tristate "Perform selftest on resizable hash table"
2208 Enable this option to test the rhashtable functions at boot.
2213 tristate "Perform selftest on hash functions"
2215 Enable this option to test the kernel's integer (<linux/hash.h>),
2216 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
2217 hash functions on boot (or module load).
2219 This is intended to help people writing architecture-specific
2220 optimized versions. If unsure, say N.
2223 tristate "Perform selftest on IDA functions"
2226 tristate "Perform selftest on priority array manager"
2229 Enable this option to test priority array manager on boot
2234 config TEST_IRQ_TIMINGS
2235 bool "IRQ timings selftest"
2236 depends on IRQ_TIMINGS
2238 Enable this option to test the irq timings code on boot.
2243 tristate "Test module loading with 'hello world' module"
2246 This builds the "test_module" module that emits "Hello, world"
2247 on printk when loaded. It is designed to be used for basic
2248 evaluation of the module loading subsystem (for example when
2249 validating module verification). It lacks any extra dependencies,
2250 and will not normally be loaded by the system unless explicitly
2256 tristate "Test module for compilation of bitops operations"
2259 This builds the "test_bitops" module that is much like the
2260 TEST_LKM module except that it does a basic exercise of the
2261 set/clear_bit macros and get_count_order/long to make sure there are
2262 no compiler warnings from C=1 sparse checker or -Wextra
2263 compilations. It has no dependencies and doesn't run or load unless
2264 explicitly requested by name. for example: modprobe test_bitops.
2269 tristate "Test module for stress/performance analysis of vmalloc allocator"
2274 This builds the "test_vmalloc" module that should be used for
2275 stress and performance analysis. So, any new change for vmalloc
2276 subsystem can be evaluated from performance and stability point
2281 config TEST_USER_COPY
2282 tristate "Test user/kernel boundary protections"
2285 This builds the "test_user_copy" module that runs sanity checks
2286 on the copy_to/from_user infrastructure, making sure basic
2287 user/kernel boundary testing is working. If it fails to load,
2288 a regression has been detected in the user/kernel memory boundary
2294 tristate "Test BPF filter functionality"
2297 This builds the "test_bpf" module that runs various test vectors
2298 against the BPF interpreter or BPF JIT compiler depending on the
2299 current setting. This is in particular useful for BPF JIT compiler
2300 development, but also to run regression tests against changes in
2301 the interpreter code. It also enables test stubs for eBPF maps and
2302 verifier used by user space verifier testsuite.
2306 config TEST_BLACKHOLE_DEV
2307 tristate "Test blackhole netdev functionality"
2310 This builds the "test_blackhole_dev" module that validates the
2311 data path through this blackhole netdev.
2315 config FIND_BIT_BENCHMARK
2316 tristate "Test find_bit functions"
2318 This builds the "test_find_bit" module that measure find_*_bit()
2319 functions performance.
2323 config TEST_FIRMWARE
2324 tristate "Test firmware loading via userspace interface"
2325 depends on FW_LOADER
2327 This builds the "test_firmware" module that creates a userspace
2328 interface for testing firmware loading. This can be used to
2329 control the triggering of firmware loading without needing an
2330 actual firmware-using device. The contents can be rechecked by
2336 tristate "sysctl test driver"
2337 depends on PROC_SYSCTL
2339 This builds the "test_sysctl" module. This driver enables to test the
2340 proc sysctl interfaces available to drivers safely without affecting
2341 production knobs which might alter system functionality.
2345 config BITFIELD_KUNIT
2346 tristate "KUnit test bitfield functions at runtime"
2349 Enable this option to test the bitfield functions at boot.
2351 KUnit tests run during boot and output the results to the debug log
2352 in TAP format (http://testanything.org/). Only useful for kernel devs
2353 running the KUnit test harness, and not intended for inclusion into a
2356 For more information on KUnit and unit tests in general please refer
2357 to the KUnit documentation in Documentation/dev-tools/kunit/.
2361 config RESOURCE_KUNIT_TEST
2362 tristate "KUnit test for resource API"
2365 This builds the resource API unit test.
2366 Tests the logic of API provided by resource.c and ioport.h.
2367 For more information on KUnit and unit tests in general please refer
2368 to the KUnit documentation in Documentation/dev-tools/kunit/.
2372 config SYSCTL_KUNIT_TEST
2373 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2375 default KUNIT_ALL_TESTS
2377 This builds the proc sysctl unit test, which runs on boot.
2378 Tests the API contract and implementation correctness of sysctl.
2379 For more information on KUnit and unit tests in general please refer
2380 to the KUnit documentation in Documentation/dev-tools/kunit/.
2384 config LIST_KUNIT_TEST
2385 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2387 default KUNIT_ALL_TESTS
2389 This builds the linked list KUnit test suite.
2390 It tests that the API and basic functionality of the list_head type
2391 and associated macros.
2393 KUnit tests run during boot and output the results to the debug log
2394 in TAP format (https://testanything.org/). Only useful for kernel devs
2395 running the KUnit test harness, and not intended for inclusion into a
2398 For more information on KUnit and unit tests in general please refer
2399 to the KUnit documentation in Documentation/dev-tools/kunit/.
2403 config LINEAR_RANGES_TEST
2404 tristate "KUnit test for linear_ranges"
2406 select LINEAR_RANGES
2408 This builds the linear_ranges unit test, which runs on boot.
2409 Tests the linear_ranges logic correctness.
2410 For more information on KUnit and unit tests in general please refer
2411 to the KUnit documentation in Documentation/dev-tools/kunit/.
2415 config CMDLINE_KUNIT_TEST
2416 tristate "KUnit test for cmdline API"
2419 This builds the cmdline API unit test.
2420 Tests the logic of API provided by cmdline.c.
2421 For more information on KUnit and unit tests in general please refer
2422 to the KUnit documentation in Documentation/dev-tools/kunit/.
2427 tristate "KUnit test for bits.h"
2430 This builds the bits unit test.
2431 Tests the logic of macros defined in bits.h.
2432 For more information on KUnit and unit tests in general please refer
2433 to the KUnit documentation in Documentation/dev-tools/kunit/.
2437 config SLUB_KUNIT_TEST
2438 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2439 depends on SLUB_DEBUG && KUNIT
2440 default KUNIT_ALL_TESTS
2442 This builds SLUB allocator unit test.
2443 Tests SLUB cache debugging functionality.
2444 For more information on KUnit and unit tests in general please refer
2445 to the KUnit documentation in Documentation/dev-tools/kunit/.
2449 config RATIONAL_KUNIT_TEST
2450 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2453 default KUNIT_ALL_TESTS
2455 This builds the rational math unit test.
2456 For more information on KUnit and unit tests in general please refer
2457 to the KUnit documentation in Documentation/dev-tools/kunit/.
2462 tristate "udelay test driver"
2464 This builds the "udelay_test" module that helps to make sure
2465 that udelay() is working properly.
2469 config TEST_STATIC_KEYS
2470 tristate "Test static keys"
2473 Test the static key interfaces.
2478 tristate "kmod stress tester"
2480 depends on NETDEVICES && NET_CORE && INET # for TUN
2487 Test the kernel's module loading mechanism: kmod. kmod implements
2488 support to load modules using the Linux kernel's usermode helper.
2489 This test provides a series of tests against kmod.
2491 Although technically you can either build test_kmod as a module or
2492 into the kernel we disallow building it into the kernel since
2493 it stress tests request_module() and this will very likely cause
2494 some issues by taking over precious threads available from other
2495 module load requests, ultimately this could be fatal.
2499 tools/testing/selftests/kmod/kmod.sh --help
2503 config TEST_DEBUG_VIRTUAL
2504 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2505 depends on DEBUG_VIRTUAL
2507 Test the kernel's ability to detect incorrect calls to
2508 virt_to_phys() done against the non-linear part of the
2509 kernel's virtual address map.
2513 config TEST_MEMCAT_P
2514 tristate "Test memcat_p() helper function"
2516 Test the memcat_p() helper for correctly merging two
2517 pointer arrays together.
2521 config TEST_LIVEPATCH
2522 tristate "Test livepatching"
2524 depends on DYNAMIC_DEBUG
2525 depends on LIVEPATCH
2528 Test kernel livepatching features for correctness. The tests will
2529 load test modules that will be livepatched in various scenarios.
2531 To run all the livepatching tests:
2533 make -C tools/testing/selftests TARGETS=livepatch run_tests
2535 Alternatively, individual tests may be invoked:
2537 tools/testing/selftests/livepatch/test-callbacks.sh
2538 tools/testing/selftests/livepatch/test-livepatch.sh
2539 tools/testing/selftests/livepatch/test-shadow-vars.sh
2544 tristate "Perform selftest on object aggreration manager"
2548 Enable this option to test object aggregation manager on boot
2552 config TEST_STACKINIT
2553 tristate "Test level of stack variable initialization"
2555 Test if the kernel is zero-initializing stack variables and
2556 padding. Coverage is controlled by compiler flags,
2557 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2558 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2563 tristate "Test heap/page initialization"
2565 Test if the kernel is zero-initializing heap and page allocations.
2566 This can be useful to test init_on_alloc and init_on_free features.
2571 tristate "Test HMM (Heterogeneous Memory Management)"
2572 depends on TRANSPARENT_HUGEPAGE
2573 depends on DEVICE_PRIVATE
2577 This is a pseudo device driver solely for testing HMM.
2578 Say M here if you want to build the HMM test module.
2579 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2583 config TEST_FREE_PAGES
2584 tristate "Test freeing pages"
2586 Test that a memory leak does not occur due to a race between
2587 freeing a block of pages and a speculative page reference.
2588 Loading this module is safe if your kernel has the bug fixed.
2589 If the bug is not fixed, it will leak gigabytes of memory and
2590 probably OOM your system.
2593 tristate "Test floating point operations in kernel space"
2594 depends on X86 && !KCOV_INSTRUMENT_ALL
2596 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2597 which will trigger a sequence of floating point operations. This is used
2598 for self-testing floating point control register setting in
2603 config TEST_CLOCKSOURCE_WATCHDOG
2604 tristate "Test clocksource watchdog in kernel space"
2605 depends on CLOCKSOURCE_WATCHDOG
2607 Enable this option to create a kernel module that will trigger
2608 a test of the clocksource watchdog. This module may be loaded
2609 via modprobe or insmod in which case it will run upon being
2610 loaded, or it may be built in, in which case it will run
2615 endif # RUNTIME_TESTING_MENU
2617 config ARCH_USE_MEMTEST
2620 An architecture should select this when it uses early_memtest()
2621 during boot process.
2625 depends on ARCH_USE_MEMTEST
2627 This option adds a kernel parameter 'memtest', which allows memtest
2628 to be set and executed.
2629 memtest=0, mean disabled; -- default
2630 memtest=1, mean do 1 test pattern;
2632 memtest=17, mean do 17 test patterns.
2633 If you are unsure how to answer this question, answer N.
2637 config HYPERV_TESTING
2638 bool "Microsoft Hyper-V driver testing"
2640 depends on HYPERV && DEBUG_FS
2642 Select this option to enable Hyper-V vmbus testing.
2644 endmenu # "Kernel Testing and Coverage"
2646 source "Documentation/Kconfig"
2648 endmenu # Kernel hacking
git.samba.org / sfrench / cifs-2.6.git / blob