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.
259 config DEBUG_INFO_DWARF4
260 bool "Generate dwarf4 debuginfo"
261 depends on $(cc-option,-gdwarf-4)
263 Generate dwarf4 debug info. This requires recent versions
264 of gcc and gdb. It makes the debug information larger.
265 But it significantly improves the success of resolving
266 variables in gdb on optimized code.
268 config DEBUG_INFO_BTF
269 bool "Generate BTF typeinfo"
270 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
271 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
273 Generate deduplicated BTF type information from DWARF debug info.
274 Turning this on expects presence of pahole tool, which will convert
275 DWARF type info into equivalent deduplicated BTF type info.
277 config PAHOLE_HAS_SPLIT_BTF
278 def_bool $(success, test `$(PAHOLE) --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/'` -ge "119")
280 config DEBUG_INFO_BTF_MODULES
282 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
284 Generate compact split BTF type information for kernel modules.
287 bool "Provide GDB scripts for kernel debugging"
289 This creates the required links to GDB helper scripts in the
290 build directory. If you load vmlinux into gdb, the helper
291 scripts will be automatically imported by gdb as well, and
292 additional functions are available to analyze a Linux kernel
293 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
299 int "Warn for stack frames larger than"
301 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
302 default 1280 if (!64BIT && PARISC)
303 default 1024 if (!64BIT && !PARISC)
304 default 2048 if 64BIT
306 Tell gcc to warn at build time for stack frames larger than this.
307 Setting this too low will cause a lot of warnings.
308 Setting it to 0 disables the warning.
310 config STRIP_ASM_SYMS
311 bool "Strip assembler-generated symbols during link"
314 Strip internal assembler-generated symbols during a link (symbols
315 that look like '.Lxxx') so they don't pollute the output of
316 get_wchan() and suchlike.
319 bool "Generate readable assembler code"
320 depends on DEBUG_KERNEL
322 Disable some compiler optimizations that tend to generate human unreadable
323 assembler output. This may make the kernel slightly slower, but it helps
324 to keep kernel developers who have to stare a lot at assembler listings
327 config HEADERS_INSTALL
328 bool "Install uapi headers to usr/include"
331 This option will install uapi headers (headers exported to user-space)
332 into the usr/include directory for use during the kernel build.
333 This is unneeded for building the kernel itself, but needed for some
334 user-space program samples. It is also needed by some features such
335 as uapi header sanity checks.
337 config DEBUG_SECTION_MISMATCH
338 bool "Enable full Section mismatch analysis"
340 The section mismatch analysis checks if there are illegal
341 references from one section to another section.
342 During linktime or runtime, some sections are dropped;
343 any use of code/data previously in these sections would
344 most likely result in an oops.
345 In the code, functions and variables are annotated with
346 __init,, etc. (see the full list in include/linux/init.h),
347 which results in the code/data being placed in specific sections.
348 The section mismatch analysis is always performed after a full
349 kernel build, and enabling this option causes the following
350 additional step to occur:
351 - Add the option -fno-inline-functions-called-once to gcc commands.
352 When inlining a function annotated with __init in a non-init
353 function, we would lose the section information and thus
354 the analysis would not catch the illegal reference.
355 This option tells gcc to inline less (but it does result in
358 config SECTION_MISMATCH_WARN_ONLY
359 bool "Make section mismatch errors non-fatal"
362 If you say N here, the build process will fail if there are any
363 section mismatch, instead of just throwing warnings.
367 config DEBUG_FORCE_FUNCTION_ALIGN_32B
368 bool "Force all function address 32B aligned" if EXPERT
370 There are cases that a commit from one domain changes the function
371 address alignment of other domains, and cause magic performance
372 bump (regression or improvement). Enable this option will help to
373 verify if the bump is caused by function alignment changes, while
374 it will slightly increase the kernel size and affect icache usage.
376 It is mainly for debug and performance tuning use.
379 # Select this config option from the architecture Kconfig, if it
380 # is preferred to always offer frame pointers as a config
381 # option on the architecture (regardless of KERNEL_DEBUG):
383 config ARCH_WANT_FRAME_POINTERS
387 bool "Compile the kernel with frame pointers"
388 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
389 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
391 If you say Y here the resulting kernel image will be slightly
392 larger and slower, but it gives very useful debugging information
393 in case of kernel bugs. (precise oopses/stacktraces/warnings)
395 config STACK_VALIDATION
396 bool "Compile-time stack metadata validation"
397 depends on HAVE_STACK_VALIDATION
400 Add compile-time checks to validate stack metadata, including frame
401 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
402 that runtime stack traces are more reliable.
404 This is also a prerequisite for generation of ORC unwind data, which
405 is needed for CONFIG_UNWINDER_ORC.
407 For more information, see
408 tools/objtool/Documentation/stack-validation.txt.
410 config VMLINUX_VALIDATION
412 depends on STACK_VALIDATION && DEBUG_ENTRY && !PARAVIRT
415 config DEBUG_FORCE_WEAK_PER_CPU
416 bool "Force weak per-cpu definitions"
417 depends on DEBUG_KERNEL
419 s390 and alpha require percpu variables in modules to be
420 defined weak to work around addressing range issue which
421 puts the following two restrictions on percpu variable
424 1. percpu symbols must be unique whether static or not
425 2. percpu variables can't be defined inside a function
427 To ensure that generic code follows the above rules, this
428 option forces all percpu variables to be defined as weak.
430 endmenu # "Compiler options"
432 menu "Generic Kernel Debugging Instruments"
435 bool "Magic SysRq key"
438 If you say Y here, you will have some control over the system even
439 if the system crashes for example during kernel debugging (e.g., you
440 will be able to flush the buffer cache to disk, reboot the system
441 immediately or dump some status information). This is accomplished
442 by pressing various keys while holding SysRq (Alt+PrintScreen). It
443 also works on a serial console (on PC hardware at least), if you
444 send a BREAK and then within 5 seconds a command keypress. The
445 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
446 Don't say Y unless you really know what this hack does.
448 config MAGIC_SYSRQ_DEFAULT_ENABLE
449 hex "Enable magic SysRq key functions by default"
450 depends on MAGIC_SYSRQ
453 Specifies which SysRq key functions are enabled by default.
454 This may be set to 1 or 0 to enable or disable them all, or
455 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
457 config MAGIC_SYSRQ_SERIAL
458 bool "Enable magic SysRq key over serial"
459 depends on MAGIC_SYSRQ
462 Many embedded boards have a disconnected TTL level serial which can
463 generate some garbage that can lead to spurious false sysrq detects.
464 This option allows you to decide whether you want to enable the
467 config MAGIC_SYSRQ_SERIAL_SEQUENCE
468 string "Char sequence that enables magic SysRq over serial"
469 depends on MAGIC_SYSRQ_SERIAL
472 Specifies a sequence of characters that can follow BREAK to enable
473 SysRq on a serial console.
475 If unsure, leave an empty string and the option will not be enabled.
478 bool "Debug Filesystem"
480 debugfs is a virtual file system that kernel developers use to put
481 debugging files into. Enable this option to be able to read and
482 write to these files.
484 For detailed documentation on the debugfs API, see
485 Documentation/filesystems/.
490 prompt "Debugfs default access"
492 default DEBUG_FS_ALLOW_ALL
494 This selects the default access restrictions for debugfs.
495 It can be overridden with kernel command line option
496 debugfs=[on,no-mount,off]. The restrictions apply for API access
497 and filesystem registration.
499 config DEBUG_FS_ALLOW_ALL
502 No restrictions apply. Both API and filesystem registration
503 is on. This is the normal default operation.
505 config DEBUG_FS_DISALLOW_MOUNT
506 bool "Do not register debugfs as filesystem"
508 The API is open but filesystem is not loaded. Clients can still do
509 their work and read with debug tools that do not need
512 config DEBUG_FS_ALLOW_NONE
515 Access is off. Clients get -PERM when trying to create nodes in
516 debugfs tree and debugfs is not registered as a filesystem.
517 Client can then back-off or continue without debugfs access.
521 source "lib/Kconfig.kgdb"
522 source "lib/Kconfig.ubsan"
523 source "lib/Kconfig.kcsan"
528 bool "Kernel debugging"
530 Say Y here if you are developing drivers or trying to debug and
531 identify kernel problems.
534 bool "Miscellaneous debug code"
536 depends on DEBUG_KERNEL
538 Say Y here if you need to enable miscellaneous debug code that should
539 be under a more specific debug option but isn't.
542 menu "Memory Debugging"
544 source "mm/Kconfig.debug"
547 bool "Debug object operations"
548 depends on DEBUG_KERNEL
550 If you say Y here, additional code will be inserted into the
551 kernel to track the life time of various objects and validate
552 the operations on those objects.
554 config DEBUG_OBJECTS_SELFTEST
555 bool "Debug objects selftest"
556 depends on DEBUG_OBJECTS
558 This enables the selftest of the object debug code.
560 config DEBUG_OBJECTS_FREE
561 bool "Debug objects in freed memory"
562 depends on DEBUG_OBJECTS
564 This enables checks whether a k/v free operation frees an area
565 which contains an object which has not been deactivated
566 properly. This can make kmalloc/kfree-intensive workloads
569 config DEBUG_OBJECTS_TIMERS
570 bool "Debug timer objects"
571 depends on DEBUG_OBJECTS
573 If you say Y here, additional code will be inserted into the
574 timer routines to track the life time of timer objects and
575 validate the timer operations.
577 config DEBUG_OBJECTS_WORK
578 bool "Debug work objects"
579 depends on DEBUG_OBJECTS
581 If you say Y here, additional code will be inserted into the
582 work queue routines to track the life time of work objects and
583 validate the work operations.
585 config DEBUG_OBJECTS_RCU_HEAD
586 bool "Debug RCU callbacks objects"
587 depends on DEBUG_OBJECTS
589 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
591 config DEBUG_OBJECTS_PERCPU_COUNTER
592 bool "Debug percpu counter objects"
593 depends on DEBUG_OBJECTS
595 If you say Y here, additional code will be inserted into the
596 percpu counter routines to track the life time of percpu counter
597 objects and validate the percpu counter operations.
599 config DEBUG_OBJECTS_ENABLE_DEFAULT
600 int "debug_objects bootup default value (0-1)"
603 depends on DEBUG_OBJECTS
605 Debug objects boot parameter default value
608 bool "Debug slab memory allocations"
609 depends on DEBUG_KERNEL && SLAB
611 Say Y here to have the kernel do limited verification on memory
612 allocation as well as poisoning memory on free to catch use of freed
613 memory. This can make kmalloc/kfree-intensive workloads much slower.
616 bool "SLUB debugging on by default"
617 depends on SLUB && SLUB_DEBUG
620 Boot with debugging on by default. SLUB boots by default with
621 the runtime debug capabilities switched off. Enabling this is
622 equivalent to specifying the "slub_debug" parameter on boot.
623 There is no support for more fine grained debug control like
624 possible with slub_debug=xxx. SLUB debugging may be switched
625 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
630 bool "Enable SLUB performance statistics"
631 depends on SLUB && SYSFS
633 SLUB statistics are useful to debug SLUBs allocation behavior in
634 order find ways to optimize the allocator. This should never be
635 enabled for production use since keeping statistics slows down
636 the allocator by a few percentage points. The slabinfo command
637 supports the determination of the most active slabs to figure
638 out which slabs are relevant to a particular load.
639 Try running: slabinfo -DA
641 config HAVE_DEBUG_KMEMLEAK
644 config DEBUG_KMEMLEAK
645 bool "Kernel memory leak detector"
646 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
648 select STACKTRACE if STACKTRACE_SUPPORT
652 Say Y here if you want to enable the memory leak
653 detector. The memory allocation/freeing is traced in a way
654 similar to the Boehm's conservative garbage collector, the
655 difference being that the orphan objects are not freed but
656 only shown in /sys/kernel/debug/kmemleak. Enabling this
657 feature will introduce an overhead to memory
658 allocations. See Documentation/dev-tools/kmemleak.rst for more
661 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
662 of finding leaks due to the slab objects poisoning.
664 In order to access the kmemleak file, debugfs needs to be
665 mounted (usually at /sys/kernel/debug).
667 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
668 int "Kmemleak memory pool size"
669 depends on DEBUG_KMEMLEAK
673 Kmemleak must track all the memory allocations to avoid
674 reporting false positives. Since memory may be allocated or
675 freed before kmemleak is fully initialised, use a static pool
676 of metadata objects to track such callbacks. After kmemleak is
677 fully initialised, this memory pool acts as an emergency one
678 if slab allocations fail.
680 config DEBUG_KMEMLEAK_TEST
681 tristate "Simple test for the kernel memory leak detector"
682 depends on DEBUG_KMEMLEAK && m
684 This option enables a module that explicitly leaks memory.
688 config DEBUG_KMEMLEAK_DEFAULT_OFF
689 bool "Default kmemleak to off"
690 depends on DEBUG_KMEMLEAK
692 Say Y here to disable kmemleak by default. It can then be enabled
693 on the command line via kmemleak=on.
695 config DEBUG_KMEMLEAK_AUTO_SCAN
696 bool "Enable kmemleak auto scan thread on boot up"
698 depends on DEBUG_KMEMLEAK
700 Depending on the cpu, kmemleak scan may be cpu intensive and can
701 stall user tasks at times. This option enables/disables automatic
702 kmemleak scan at boot up.
704 Say N here to disable kmemleak auto scan thread to stop automatic
705 scanning. Disabling this option disables automatic reporting of
710 config DEBUG_STACK_USAGE
711 bool "Stack utilization instrumentation"
712 depends on DEBUG_KERNEL && !IA64
714 Enables the display of the minimum amount of free stack which each
715 task has ever had available in the sysrq-T and sysrq-P debug output.
717 This option will slow down process creation somewhat.
719 config SCHED_STACK_END_CHECK
720 bool "Detect stack corruption on calls to schedule()"
721 depends on DEBUG_KERNEL
724 This option checks for a stack overrun on calls to schedule().
725 If the stack end location is found to be over written always panic as
726 the content of the corrupted region can no longer be trusted.
727 This is to ensure no erroneous behaviour occurs which could result in
728 data corruption or a sporadic crash at a later stage once the region
729 is examined. The runtime overhead introduced is minimal.
731 config ARCH_HAS_DEBUG_VM_PGTABLE
734 An architecture should select this when it can successfully
735 build and run DEBUG_VM_PGTABLE.
739 depends on DEBUG_KERNEL
741 Enable this to turn on extended checks in the virtual-memory system
742 that may impact performance.
746 config DEBUG_VM_VMACACHE
747 bool "Debug VMA caching"
750 Enable this to turn on VMA caching debug information. Doing so
751 can cause significant overhead, so only enable it in non-production
757 bool "Debug VM red-black trees"
760 Enable VM red-black tree debugging information and extra validations.
764 config DEBUG_VM_PGFLAGS
765 bool "Debug page-flags operations"
768 Enables extra validation on page flags operations.
772 config DEBUG_VM_PGTABLE
773 bool "Debug arch page table for semantics compliance"
775 depends on ARCH_HAS_DEBUG_VM_PGTABLE
776 default y if DEBUG_VM
778 This option provides a debug method which can be used to test
779 architecture page table helper functions on various platforms in
780 verifying if they comply with expected generic MM semantics. This
781 will help architecture code in making sure that any changes or
782 new additions of these helpers still conform to expected
783 semantics of the generic MM. Platforms will have to opt in for
784 this through ARCH_HAS_DEBUG_VM_PGTABLE.
788 config ARCH_HAS_DEBUG_VIRTUAL
792 bool "Debug VM translations"
793 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
795 Enable some costly sanity checks in virtual to page code. This can
796 catch mistakes with virt_to_page() and friends.
800 config DEBUG_NOMMU_REGIONS
801 bool "Debug the global anon/private NOMMU mapping region tree"
802 depends on DEBUG_KERNEL && !MMU
804 This option causes the global tree of anonymous and private mapping
805 regions to be regularly checked for invalid topology.
807 config DEBUG_MEMORY_INIT
808 bool "Debug memory initialisation" if EXPERT
811 Enable this for additional checks during memory initialisation.
812 The sanity checks verify aspects of the VM such as the memory model
813 and other information provided by the architecture. Verbose
814 information will be printed at KERN_DEBUG loglevel depending
815 on the mminit_loglevel= command-line option.
819 config MEMORY_NOTIFIER_ERROR_INJECT
820 tristate "Memory hotplug notifier error injection module"
821 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
823 This option provides the ability to inject artificial errors to
824 memory hotplug notifier chain callbacks. It is controlled through
825 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
827 If the notifier call chain should be failed with some events
828 notified, write the error code to "actions/<notifier event>/error".
830 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
832 # cd /sys/kernel/debug/notifier-error-inject/memory
833 # echo -12 > actions/MEM_GOING_OFFLINE/error
834 # echo offline > /sys/devices/system/memory/memoryXXX/state
835 bash: echo: write error: Cannot allocate memory
837 To compile this code as a module, choose M here: the module will
838 be called memory-notifier-error-inject.
842 config DEBUG_PER_CPU_MAPS
843 bool "Debug access to per_cpu maps"
844 depends on DEBUG_KERNEL
847 Say Y to verify that the per_cpu map being accessed has
848 been set up. This adds a fair amount of code to kernel memory
849 and decreases performance.
853 config DEBUG_KMAP_LOCAL
854 bool "Debug kmap_local temporary mappings"
855 depends on DEBUG_KERNEL && KMAP_LOCAL
857 This option enables additional error checking for the kmap_local
858 infrastructure. Disable for production use.
860 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
863 config DEBUG_KMAP_LOCAL_FORCE_MAP
864 bool "Enforce kmap_local temporary mappings"
865 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
867 select DEBUG_KMAP_LOCAL
869 This option enforces temporary mappings through the kmap_local
870 mechanism for non-highmem pages and on non-highmem systems.
871 Disable this for production systems!
874 bool "Highmem debugging"
875 depends on DEBUG_KERNEL && HIGHMEM
876 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
877 select DEBUG_KMAP_LOCAL
879 This option enables additional error checking for high memory
880 systems. Disable for production systems.
882 config HAVE_DEBUG_STACKOVERFLOW
885 config DEBUG_STACKOVERFLOW
886 bool "Check for stack overflows"
887 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
889 Say Y here if you want to check for overflows of kernel, IRQ
890 and exception stacks (if your architecture uses them). This
891 option will show detailed messages if free stack space drops
892 below a certain limit.
894 These kinds of bugs usually occur when call-chains in the
895 kernel get too deep, especially when interrupts are
898 Use this in cases where you see apparently random memory
899 corruption, especially if it appears in 'struct thread_info'
901 If in doubt, say "N".
903 source "lib/Kconfig.kasan"
905 endmenu # "Memory Debugging"
908 bool "Debug shared IRQ handlers"
909 depends on DEBUG_KERNEL
911 Enable this to generate a spurious interrupt just before a shared
912 interrupt handler is deregistered (generating one when registering
913 is currently disabled). Drivers need to handle this correctly. Some
914 don't and need to be caught.
916 menu "Debug Oops, Lockups and Hangs"
921 Say Y here to enable the kernel to panic when it oopses. This
922 has the same effect as setting oops=panic on the kernel command
925 This feature is useful to ensure that the kernel does not do
926 anything erroneous after an oops which could result in data
927 corruption or other issues.
931 config PANIC_ON_OOPS_VALUE
934 default 0 if !PANIC_ON_OOPS
935 default 1 if PANIC_ON_OOPS
941 Set the timeout value (in seconds) until a reboot occurs when
942 the kernel panics. If n = 0, then we wait forever. A timeout
943 value n > 0 will wait n seconds before rebooting, while a timeout
944 value n < 0 will reboot immediately.
946 config LOCKUP_DETECTOR
949 config SOFTLOCKUP_DETECTOR
950 bool "Detect Soft Lockups"
951 depends on DEBUG_KERNEL && !S390
952 select LOCKUP_DETECTOR
954 Say Y here to enable the kernel to act as a watchdog to detect
957 Softlockups are bugs that cause the kernel to loop in kernel
958 mode for more than 20 seconds, without giving other tasks a
959 chance to run. The current stack trace is displayed upon
960 detection and the system will stay locked up.
962 config BOOTPARAM_SOFTLOCKUP_PANIC
963 bool "Panic (Reboot) On Soft Lockups"
964 depends on SOFTLOCKUP_DETECTOR
966 Say Y here to enable the kernel to panic on "soft lockups",
967 which are bugs that cause the kernel to loop in kernel
968 mode for more than 20 seconds (configurable using the watchdog_thresh
969 sysctl), without giving other tasks a chance to run.
971 The panic can be used in combination with panic_timeout,
972 to cause the system to reboot automatically after a
973 lockup has been detected. This feature is useful for
974 high-availability systems that have uptime guarantees and
975 where a lockup must be resolved ASAP.
979 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
981 depends on SOFTLOCKUP_DETECTOR
983 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
984 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
986 config HARDLOCKUP_DETECTOR_PERF
988 select SOFTLOCKUP_DETECTOR
991 # Enables a timestamp based low pass filter to compensate for perf based
992 # hard lockup detection which runs too fast due to turbo modes.
994 config HARDLOCKUP_CHECK_TIMESTAMP
998 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
999 # lockup detector rather than the perf based detector.
1001 config HARDLOCKUP_DETECTOR
1002 bool "Detect Hard Lockups"
1003 depends on DEBUG_KERNEL && !S390
1004 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1005 select LOCKUP_DETECTOR
1006 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1007 select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH
1009 Say Y here to enable the kernel to act as a watchdog to detect
1012 Hardlockups are bugs that cause the CPU to loop in kernel mode
1013 for more than 10 seconds, without letting other interrupts have a
1014 chance to run. The current stack trace is displayed upon detection
1015 and the system will stay locked up.
1017 config BOOTPARAM_HARDLOCKUP_PANIC
1018 bool "Panic (Reboot) On Hard Lockups"
1019 depends on HARDLOCKUP_DETECTOR
1021 Say Y here to enable the kernel to panic on "hard lockups",
1022 which are bugs that cause the kernel to loop in kernel
1023 mode with interrupts disabled for more than 10 seconds (configurable
1024 using the watchdog_thresh sysctl).
1028 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
1030 depends on HARDLOCKUP_DETECTOR
1032 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
1033 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
1035 config DETECT_HUNG_TASK
1036 bool "Detect Hung Tasks"
1037 depends on DEBUG_KERNEL
1038 default SOFTLOCKUP_DETECTOR
1040 Say Y here to enable the kernel to detect "hung tasks",
1041 which are bugs that cause the task to be stuck in
1042 uninterruptible "D" state indefinitely.
1044 When a hung task is detected, the kernel will print the
1045 current stack trace (which you should report), but the
1046 task will stay in uninterruptible state. If lockdep is
1047 enabled then all held locks will also be reported. This
1048 feature has negligible overhead.
1050 config DEFAULT_HUNG_TASK_TIMEOUT
1051 int "Default timeout for hung task detection (in seconds)"
1052 depends on DETECT_HUNG_TASK
1055 This option controls the default timeout (in seconds) used
1056 to determine when a task has become non-responsive and should
1059 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1060 sysctl or by writing a value to
1061 /proc/sys/kernel/hung_task_timeout_secs.
1063 A timeout of 0 disables the check. The default is two minutes.
1064 Keeping the default should be fine in most cases.
1066 config BOOTPARAM_HUNG_TASK_PANIC
1067 bool "Panic (Reboot) On Hung Tasks"
1068 depends on DETECT_HUNG_TASK
1070 Say Y here to enable the kernel to panic on "hung tasks",
1071 which are bugs that cause the kernel to leave a task stuck
1072 in uninterruptible "D" state.
1074 The panic can be used in combination with panic_timeout,
1075 to cause the system to reboot automatically after a
1076 hung task has been detected. This feature is useful for
1077 high-availability systems that have uptime guarantees and
1078 where a hung tasks must be resolved ASAP.
1082 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
1084 depends on DETECT_HUNG_TASK
1086 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
1087 default 1 if BOOTPARAM_HUNG_TASK_PANIC
1090 bool "Detect Workqueue Stalls"
1091 depends on DEBUG_KERNEL
1093 Say Y here to enable stall detection on workqueues. If a
1094 worker pool doesn't make forward progress on a pending work
1095 item for over a given amount of time, 30s by default, a
1096 warning message is printed along with dump of workqueue
1097 state. This can be configured through kernel parameter
1098 "workqueue.watchdog_thresh" and its sysfs counterpart.
1101 tristate "Test module to generate lockups"
1104 This builds the "test_lockup" module that helps to make sure
1105 that watchdogs and lockup detectors are working properly.
1107 Depending on module parameters it could emulate soft or hard
1108 lockup, "hung task", or locking arbitrary lock for a long time.
1109 Also it could generate series of lockups with cooling-down periods.
1113 endmenu # "Debug lockups and hangs"
1115 menu "Scheduler Debugging"
1118 bool "Collect scheduler debugging info"
1119 depends on DEBUG_KERNEL && PROC_FS
1122 If you say Y here, the /proc/sched_debug file will be provided
1123 that can help debug the scheduler. The runtime overhead of this
1131 bool "Collect scheduler statistics"
1132 depends on DEBUG_KERNEL && PROC_FS
1135 If you say Y here, additional code will be inserted into the
1136 scheduler and related routines to collect statistics about
1137 scheduler behavior and provide them in /proc/schedstat. These
1138 stats may be useful for both tuning and debugging the scheduler
1139 If you aren't debugging the scheduler or trying to tune a specific
1140 application, you can say N to avoid the very slight overhead
1145 config DEBUG_TIMEKEEPING
1146 bool "Enable extra timekeeping sanity checking"
1148 This option will enable additional timekeeping sanity checks
1149 which may be helpful when diagnosing issues where timekeeping
1150 problems are suspected.
1152 This may include checks in the timekeeping hotpaths, so this
1153 option may have a (very small) performance impact to some
1158 config DEBUG_PREEMPT
1159 bool "Debug preemptible kernel"
1160 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1163 If you say Y here then the kernel will use a debug variant of the
1164 commonly used smp_processor_id() function and will print warnings
1165 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1166 will detect preemption count underflows.
1168 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1170 config LOCK_DEBUGGING_SUPPORT
1172 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1175 config PROVE_LOCKING
1176 bool "Lock debugging: prove locking correctness"
1177 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1179 select DEBUG_SPINLOCK
1180 select DEBUG_MUTEXES
1181 select DEBUG_RT_MUTEXES if RT_MUTEXES
1183 select DEBUG_WW_MUTEX_SLOWPATH
1184 select DEBUG_LOCK_ALLOC
1185 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1186 select TRACE_IRQFLAGS
1189 This feature enables the kernel to prove that all locking
1190 that occurs in the kernel runtime is mathematically
1191 correct: that under no circumstance could an arbitrary (and
1192 not yet triggered) combination of observed locking
1193 sequences (on an arbitrary number of CPUs, running an
1194 arbitrary number of tasks and interrupt contexts) cause a
1197 In short, this feature enables the kernel to report locking
1198 related deadlocks before they actually occur.
1200 The proof does not depend on how hard and complex a
1201 deadlock scenario would be to trigger: how many
1202 participant CPUs, tasks and irq-contexts would be needed
1203 for it to trigger. The proof also does not depend on
1204 timing: if a race and a resulting deadlock is possible
1205 theoretically (no matter how unlikely the race scenario
1206 is), it will be proven so and will immediately be
1207 reported by the kernel (once the event is observed that
1208 makes the deadlock theoretically possible).
1210 If a deadlock is impossible (i.e. the locking rules, as
1211 observed by the kernel, are mathematically correct), the
1212 kernel reports nothing.
1214 NOTE: this feature can also be enabled for rwlocks, mutexes
1215 and rwsems - in which case all dependencies between these
1216 different locking variants are observed and mapped too, and
1217 the proof of observed correctness is also maintained for an
1218 arbitrary combination of these separate locking variants.
1220 For more details, see Documentation/locking/lockdep-design.rst.
1222 config PROVE_RAW_LOCK_NESTING
1223 bool "Enable raw_spinlock - spinlock nesting checks"
1224 depends on PROVE_LOCKING
1227 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1228 that the lock nesting rules for PREEMPT_RT enabled kernels are
1231 NOTE: There are known nesting problems. So if you enable this
1232 option expect lockdep splats until these problems have been fully
1233 addressed which is work in progress. This config switch allows to
1234 identify and analyze these problems. It will be removed and the
1235 check permanentely enabled once the main issues have been fixed.
1237 If unsure, select N.
1240 bool "Lock usage statistics"
1241 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1243 select DEBUG_SPINLOCK
1244 select DEBUG_MUTEXES
1245 select DEBUG_RT_MUTEXES if RT_MUTEXES
1246 select DEBUG_LOCK_ALLOC
1249 This feature enables tracking lock contention points
1251 For more details, see Documentation/locking/lockstat.rst
1253 This also enables lock events required by "perf lock",
1255 If you want to use "perf lock", you also need to turn on
1256 CONFIG_EVENT_TRACING.
1258 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1259 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1261 config DEBUG_RT_MUTEXES
1262 bool "RT Mutex debugging, deadlock detection"
1263 depends on DEBUG_KERNEL && RT_MUTEXES
1265 This allows rt mutex semantics violations and rt mutex related
1266 deadlocks (lockups) to be detected and reported automatically.
1268 config DEBUG_SPINLOCK
1269 bool "Spinlock and rw-lock debugging: basic checks"
1270 depends on DEBUG_KERNEL
1271 select UNINLINE_SPIN_UNLOCK
1273 Say Y here and build SMP to catch missing spinlock initialization
1274 and certain other kinds of spinlock errors commonly made. This is
1275 best used in conjunction with the NMI watchdog so that spinlock
1276 deadlocks are also debuggable.
1278 config DEBUG_MUTEXES
1279 bool "Mutex debugging: basic checks"
1280 depends on DEBUG_KERNEL
1282 This feature allows mutex semantics violations to be detected and
1285 config DEBUG_WW_MUTEX_SLOWPATH
1286 bool "Wait/wound mutex debugging: Slowpath testing"
1287 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1288 select DEBUG_LOCK_ALLOC
1289 select DEBUG_SPINLOCK
1290 select DEBUG_MUTEXES
1292 This feature enables slowpath testing for w/w mutex users by
1293 injecting additional -EDEADLK wound/backoff cases. Together with
1294 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1295 will test all possible w/w mutex interface abuse with the
1296 exception of simply not acquiring all the required locks.
1297 Note that this feature can introduce significant overhead, so
1298 it really should not be enabled in a production or distro kernel,
1299 even a debug kernel. If you are a driver writer, enable it. If
1300 you are a distro, do not.
1303 bool "RW Semaphore debugging: basic checks"
1304 depends on DEBUG_KERNEL
1306 This debugging feature allows mismatched rw semaphore locks
1307 and unlocks to be detected and reported.
1309 config DEBUG_LOCK_ALLOC
1310 bool "Lock debugging: detect incorrect freeing of live locks"
1311 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1312 select DEBUG_SPINLOCK
1313 select DEBUG_MUTEXES
1314 select DEBUG_RT_MUTEXES if RT_MUTEXES
1317 This feature will check whether any held lock (spinlock, rwlock,
1318 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1319 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1320 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1321 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1322 held during task exit.
1326 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1328 select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86
1332 config LOCKDEP_SMALL
1335 config DEBUG_LOCKDEP
1336 bool "Lock dependency engine debugging"
1337 depends on DEBUG_KERNEL && LOCKDEP
1338 select DEBUG_IRQFLAGS
1340 If you say Y here, the lock dependency engine will do
1341 additional runtime checks to debug itself, at the price
1342 of more runtime overhead.
1344 config DEBUG_ATOMIC_SLEEP
1345 bool "Sleep inside atomic section checking"
1346 select PREEMPT_COUNT
1347 depends on DEBUG_KERNEL
1348 depends on !ARCH_NO_PREEMPT
1350 If you say Y here, various routines which may sleep will become very
1351 noisy if they are called inside atomic sections: when a spinlock is
1352 held, inside an rcu read side critical section, inside preempt disabled
1353 sections, inside an interrupt, etc...
1355 config DEBUG_LOCKING_API_SELFTESTS
1356 bool "Locking API boot-time self-tests"
1357 depends on DEBUG_KERNEL
1359 Say Y here if you want the kernel to run a short self-test during
1360 bootup. The self-test checks whether common types of locking bugs
1361 are detected by debugging mechanisms or not. (if you disable
1362 lock debugging then those bugs wont be detected of course.)
1363 The following locking APIs are covered: spinlocks, rwlocks,
1366 config LOCK_TORTURE_TEST
1367 tristate "torture tests for locking"
1368 depends on DEBUG_KERNEL
1371 This option provides a kernel module that runs torture tests
1372 on kernel locking primitives. The kernel module may be built
1373 after the fact on the running kernel to be tested, if desired.
1375 Say Y here if you want kernel locking-primitive torture tests
1376 to be built into the kernel.
1377 Say M if you want these torture tests to build as a module.
1378 Say N if you are unsure.
1380 config WW_MUTEX_SELFTEST
1381 tristate "Wait/wound mutex selftests"
1383 This option provides a kernel module that runs tests on the
1384 on the struct ww_mutex locking API.
1386 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1387 with this test harness.
1389 Say M if you want these self tests to build as a module.
1390 Say N if you are unsure.
1392 config SCF_TORTURE_TEST
1393 tristate "torture tests for smp_call_function*()"
1394 depends on DEBUG_KERNEL
1397 This option provides a kernel module that runs torture tests
1398 on the smp_call_function() family of primitives. The kernel
1399 module may be built after the fact on the running kernel to
1400 be tested, if desired.
1402 config CSD_LOCK_WAIT_DEBUG
1403 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1404 depends on DEBUG_KERNEL
1408 This option enables debug prints when CPUs are slow to respond
1409 to the smp_call_function*() IPI wrappers. These debug prints
1410 include the IPI handler function currently executing (if any)
1411 and relevant stack traces.
1413 endmenu # lock debugging
1415 config TRACE_IRQFLAGS
1416 depends on TRACE_IRQFLAGS_SUPPORT
1419 Enables hooks to interrupt enabling and disabling for
1420 either tracing or lock debugging.
1422 config TRACE_IRQFLAGS_NMI
1424 depends on TRACE_IRQFLAGS
1425 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1427 config DEBUG_IRQFLAGS
1428 bool "Debug IRQ flag manipulation"
1430 Enables checks for potentially unsafe enabling or disabling of
1431 interrupts, such as calling raw_local_irq_restore() when interrupts
1435 bool "Stack backtrace support"
1436 depends on STACKTRACE_SUPPORT
1438 This option causes the kernel to create a /proc/pid/stack for
1439 every process, showing its current stack trace.
1440 It is also used by various kernel debugging features that require
1441 stack trace generation.
1443 config WARN_ALL_UNSEEDED_RANDOM
1444 bool "Warn for all uses of unseeded randomness"
1447 Some parts of the kernel contain bugs relating to their use of
1448 cryptographically secure random numbers before it's actually possible
1449 to generate those numbers securely. This setting ensures that these
1450 flaws don't go unnoticed, by enabling a message, should this ever
1451 occur. This will allow people with obscure setups to know when things
1452 are going wrong, so that they might contact developers about fixing
1455 Unfortunately, on some models of some architectures getting
1456 a fully seeded CRNG is extremely difficult, and so this can
1457 result in dmesg getting spammed for a surprisingly long
1458 time. This is really bad from a security perspective, and
1459 so architecture maintainers really need to do what they can
1460 to get the CRNG seeded sooner after the system is booted.
1461 However, since users cannot do anything actionable to
1462 address this, by default the kernel will issue only a single
1463 warning for the first use of unseeded randomness.
1465 Say Y here if you want to receive warnings for all uses of
1466 unseeded randomness. This will be of use primarily for
1467 those developers interested in improving the security of
1468 Linux kernels running on their architecture (or
1471 config DEBUG_KOBJECT
1472 bool "kobject debugging"
1473 depends on DEBUG_KERNEL
1475 If you say Y here, some extra kobject debugging messages will be sent
1478 config DEBUG_KOBJECT_RELEASE
1479 bool "kobject release debugging"
1480 depends on DEBUG_OBJECTS_TIMERS
1482 kobjects are reference counted objects. This means that their
1483 last reference count put is not predictable, and the kobject can
1484 live on past the point at which a driver decides to drop it's
1485 initial reference to the kobject gained on allocation. An
1486 example of this would be a struct device which has just been
1489 However, some buggy drivers assume that after such an operation,
1490 the memory backing the kobject can be immediately freed. This
1491 goes completely against the principles of a refcounted object.
1493 If you say Y here, the kernel will delay the release of kobjects
1494 on the last reference count to improve the visibility of this
1495 kind of kobject release bug.
1497 config HAVE_DEBUG_BUGVERBOSE
1500 menu "Debug kernel data structures"
1503 bool "Debug linked list manipulation"
1504 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1506 Enable this to turn on extended checks in the linked-list
1512 bool "Debug priority linked list manipulation"
1513 depends on DEBUG_KERNEL
1515 Enable this to turn on extended checks in the priority-ordered
1516 linked-list (plist) walking routines. This checks the entire
1517 list multiple times during each manipulation.
1522 bool "Debug SG table operations"
1523 depends on DEBUG_KERNEL
1525 Enable this to turn on checks on scatter-gather tables. This can
1526 help find problems with drivers that do not properly initialize
1531 config DEBUG_NOTIFIERS
1532 bool "Debug notifier call chains"
1533 depends on DEBUG_KERNEL
1535 Enable this to turn on sanity checking for notifier call chains.
1536 This is most useful for kernel developers to make sure that
1537 modules properly unregister themselves from notifier chains.
1538 This is a relatively cheap check but if you care about maximum
1541 config BUG_ON_DATA_CORRUPTION
1542 bool "Trigger a BUG when data corruption is detected"
1545 Select this option if the kernel should BUG when it encounters
1546 data corruption in kernel memory structures when they get checked
1553 config DEBUG_CREDENTIALS
1554 bool "Debug credential management"
1555 depends on DEBUG_KERNEL
1557 Enable this to turn on some debug checking for credential
1558 management. The additional code keeps track of the number of
1559 pointers from task_structs to any given cred struct, and checks to
1560 see that this number never exceeds the usage count of the cred
1563 Furthermore, if SELinux is enabled, this also checks that the
1564 security pointer in the cred struct is never seen to be invalid.
1568 source "kernel/rcu/Kconfig.debug"
1570 config DEBUG_WQ_FORCE_RR_CPU
1571 bool "Force round-robin CPU selection for unbound work items"
1572 depends on DEBUG_KERNEL
1575 Workqueue used to implicitly guarantee that work items queued
1576 without explicit CPU specified are put on the local CPU. This
1577 guarantee is no longer true and while local CPU is still
1578 preferred work items may be put on foreign CPUs. Kernel
1579 parameter "workqueue.debug_force_rr_cpu" is added to force
1580 round-robin CPU selection to flush out usages which depend on the
1581 now broken guarantee. This config option enables the debug
1582 feature by default. When enabled, memory and cache locality will
1585 config DEBUG_BLOCK_EXT_DEVT
1586 bool "Force extended block device numbers and spread them"
1587 depends on DEBUG_KERNEL
1591 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1592 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1593 YOU ARE DOING. Distros, please enable this and fix whatever
1596 Conventionally, block device numbers are allocated from
1597 predetermined contiguous area. However, extended block area
1598 may introduce non-contiguous block device numbers. This
1599 option forces most block device numbers to be allocated from
1600 the extended space and spreads them to discover kernel or
1601 userland code paths which assume predetermined contiguous
1602 device number allocation.
1604 Note that turning on this debug option shuffles all the
1605 device numbers for all IDE and SCSI devices including libata
1606 ones, so root partition specified using device number
1607 directly (via rdev or root=MAJ:MIN) won't work anymore.
1608 Textual device names (root=/dev/sdXn) will continue to work.
1610 Say N if you are unsure.
1612 config CPU_HOTPLUG_STATE_CONTROL
1613 bool "Enable CPU hotplug state control"
1614 depends on DEBUG_KERNEL
1615 depends on HOTPLUG_CPU
1618 Allows to write steps between "offline" and "online" to the CPUs
1619 sysfs target file so states can be stepped granular. This is a debug
1620 option for now as the hotplug machinery cannot be stopped and
1621 restarted at arbitrary points yet.
1623 Say N if your are unsure.
1626 bool "Latency measuring infrastructure"
1627 depends on DEBUG_KERNEL
1628 depends on STACKTRACE_SUPPORT
1630 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
1637 Enable this option if you want to use the LatencyTOP tool
1638 to find out which userspace is blocking on what kernel operations.
1640 source "kernel/trace/Kconfig"
1642 config PROVIDE_OHCI1394_DMA_INIT
1643 bool "Remote debugging over FireWire early on boot"
1644 depends on PCI && X86
1646 If you want to debug problems which hang or crash the kernel early
1647 on boot and the crashing machine has a FireWire port, you can use
1648 this feature to remotely access the memory of the crashed machine
1649 over FireWire. This employs remote DMA as part of the OHCI1394
1650 specification which is now the standard for FireWire controllers.
1652 With remote DMA, you can monitor the printk buffer remotely using
1653 firescope and access all memory below 4GB using fireproxy from gdb.
1654 Even controlling a kernel debugger is possible using remote DMA.
1658 If ohci1394_dma=early is used as boot parameter, it will initialize
1659 all OHCI1394 controllers which are found in the PCI config space.
1661 As all changes to the FireWire bus such as enabling and disabling
1662 devices cause a bus reset and thereby disable remote DMA for all
1663 devices, be sure to have the cable plugged and FireWire enabled on
1664 the debugging host before booting the debug target for debugging.
1666 This code (~1k) is freed after boot. By then, the firewire stack
1667 in charge of the OHCI-1394 controllers should be used instead.
1669 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1671 source "samples/Kconfig"
1673 config ARCH_HAS_DEVMEM_IS_ALLOWED
1676 config STRICT_DEVMEM
1677 bool "Filter access to /dev/mem"
1678 depends on MMU && DEVMEM
1679 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1680 default y if PPC || X86 || ARM64
1682 If this option is disabled, you allow userspace (root) access to all
1683 of memory, including kernel and userspace memory. Accidental
1684 access to this is obviously disastrous, but specific access can
1685 be used by people debugging the kernel. Note that with PAT support
1686 enabled, even in this case there are restrictions on /dev/mem
1687 use due to the cache aliasing requirements.
1689 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1690 file only allows userspace access to PCI space and the BIOS code and
1691 data regions. This is sufficient for dosemu and X and all common
1696 config IO_STRICT_DEVMEM
1697 bool "Filter I/O access to /dev/mem"
1698 depends on STRICT_DEVMEM
1700 If this option is disabled, you allow userspace (root) access to all
1701 io-memory regardless of whether a driver is actively using that
1702 range. Accidental access to this is obviously disastrous, but
1703 specific access can be used by people debugging kernel drivers.
1705 If this option is switched on, the /dev/mem file only allows
1706 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1707 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1708 if the driver using a given range cannot be disabled.
1712 menu "$(SRCARCH) Debugging"
1714 source "arch/$(SRCARCH)/Kconfig.debug"
1718 menu "Kernel Testing and Coverage"
1720 source "lib/kunit/Kconfig"
1722 config NOTIFIER_ERROR_INJECTION
1723 tristate "Notifier error injection"
1724 depends on DEBUG_KERNEL
1727 This option provides the ability to inject artificial errors to
1728 specified notifier chain callbacks. It is useful to test the error
1729 handling of notifier call chain failures.
1733 config PM_NOTIFIER_ERROR_INJECT
1734 tristate "PM notifier error injection module"
1735 depends on PM && NOTIFIER_ERROR_INJECTION
1736 default m if PM_DEBUG
1738 This option provides the ability to inject artificial errors to
1739 PM notifier chain callbacks. It is controlled through debugfs
1740 interface /sys/kernel/debug/notifier-error-inject/pm
1742 If the notifier call chain should be failed with some events
1743 notified, write the error code to "actions/<notifier event>/error".
1745 Example: Inject PM suspend error (-12 = -ENOMEM)
1747 # cd /sys/kernel/debug/notifier-error-inject/pm/
1748 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1749 # echo mem > /sys/power/state
1750 bash: echo: write error: Cannot allocate memory
1752 To compile this code as a module, choose M here: the module will
1753 be called pm-notifier-error-inject.
1757 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1758 tristate "OF reconfig notifier error injection module"
1759 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1761 This option provides the ability to inject artificial errors to
1762 OF reconfig notifier chain callbacks. It is controlled
1763 through debugfs interface under
1764 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1766 If the notifier call chain should be failed with some events
1767 notified, write the error code to "actions/<notifier event>/error".
1769 To compile this code as a module, choose M here: the module will
1770 be called of-reconfig-notifier-error-inject.
1774 config NETDEV_NOTIFIER_ERROR_INJECT
1775 tristate "Netdev notifier error injection module"
1776 depends on NET && NOTIFIER_ERROR_INJECTION
1778 This option provides the ability to inject artificial errors to
1779 netdevice notifier chain callbacks. It is controlled through debugfs
1780 interface /sys/kernel/debug/notifier-error-inject/netdev
1782 If the notifier call chain should be failed with some events
1783 notified, write the error code to "actions/<notifier event>/error".
1785 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1787 # cd /sys/kernel/debug/notifier-error-inject/netdev
1788 # echo -22 > actions/NETDEV_CHANGEMTU/error
1789 # ip link set eth0 mtu 1024
1790 RTNETLINK answers: Invalid argument
1792 To compile this code as a module, choose M here: the module will
1793 be called netdev-notifier-error-inject.
1797 config FUNCTION_ERROR_INJECTION
1799 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1801 config FAULT_INJECTION
1802 bool "Fault-injection framework"
1803 depends on DEBUG_KERNEL
1805 Provide fault-injection framework.
1806 For more details, see Documentation/fault-injection/.
1809 bool "Fault-injection capability for kmalloc"
1810 depends on FAULT_INJECTION
1811 depends on SLAB || SLUB
1813 Provide fault-injection capability for kmalloc.
1815 config FAIL_PAGE_ALLOC
1816 bool "Fault-injection capability for alloc_pages()"
1817 depends on FAULT_INJECTION
1819 Provide fault-injection capability for alloc_pages().
1821 config FAULT_INJECTION_USERCOPY
1822 bool "Fault injection capability for usercopy functions"
1823 depends on FAULT_INJECTION
1825 Provides fault-injection capability to inject failures
1826 in usercopy functions (copy_from_user(), get_user(), ...).
1828 config FAIL_MAKE_REQUEST
1829 bool "Fault-injection capability for disk IO"
1830 depends on FAULT_INJECTION && BLOCK
1832 Provide fault-injection capability for disk IO.
1834 config FAIL_IO_TIMEOUT
1835 bool "Fault-injection capability for faking disk interrupts"
1836 depends on FAULT_INJECTION && BLOCK
1838 Provide fault-injection capability on end IO handling. This
1839 will make the block layer "forget" an interrupt as configured,
1840 thus exercising the error handling.
1842 Only works with drivers that use the generic timeout handling,
1843 for others it wont do anything.
1846 bool "Fault-injection capability for futexes"
1848 depends on FAULT_INJECTION && FUTEX
1850 Provide fault-injection capability for futexes.
1852 config FAULT_INJECTION_DEBUG_FS
1853 bool "Debugfs entries for fault-injection capabilities"
1854 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1856 Enable configuration of fault-injection capabilities via debugfs.
1858 config FAIL_FUNCTION
1859 bool "Fault-injection capability for functions"
1860 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1862 Provide function-based fault-injection capability.
1863 This will allow you to override a specific function with a return
1864 with given return value. As a result, function caller will see
1865 an error value and have to handle it. This is useful to test the
1866 error handling in various subsystems.
1868 config FAIL_MMC_REQUEST
1869 bool "Fault-injection capability for MMC IO"
1870 depends on FAULT_INJECTION_DEBUG_FS && MMC
1872 Provide fault-injection capability for MMC IO.
1873 This will make the mmc core return data errors. This is
1874 useful to test the error handling in the mmc block device
1875 and to test how the mmc host driver handles retries from
1878 config FAULT_INJECTION_STACKTRACE_FILTER
1879 bool "stacktrace filter for fault-injection capabilities"
1880 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1883 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
1885 Provide stacktrace filter for fault-injection capabilities
1887 config ARCH_HAS_KCOV
1890 An architecture should select this when it can successfully
1891 build and run with CONFIG_KCOV. This typically requires
1892 disabling instrumentation for some early boot code.
1894 config CC_HAS_SANCOV_TRACE_PC
1895 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1899 bool "Code coverage for fuzzing"
1900 depends on ARCH_HAS_KCOV
1901 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1903 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1905 KCOV exposes kernel code coverage information in a form suitable
1906 for coverage-guided fuzzing (randomized testing).
1908 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1909 different machines and across reboots. If you need stable PC values,
1910 disable RANDOMIZE_BASE.
1912 For more details, see Documentation/dev-tools/kcov.rst.
1914 config KCOV_ENABLE_COMPARISONS
1915 bool "Enable comparison operands collection by KCOV"
1917 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
1919 KCOV also exposes operands of every comparison in the instrumented
1920 code along with operand sizes and PCs of the comparison instructions.
1921 These operands can be used by fuzzing engines to improve the quality
1922 of fuzzing coverage.
1924 config KCOV_INSTRUMENT_ALL
1925 bool "Instrument all code by default"
1929 If you are doing generic system call fuzzing (like e.g. syzkaller),
1930 then you will want to instrument the whole kernel and you should
1931 say y here. If you are doing more targeted fuzzing (like e.g.
1932 filesystem fuzzing with AFL) then you will want to enable coverage
1933 for more specific subsets of files, and should say n here.
1935 config KCOV_IRQ_AREA_SIZE
1936 hex "Size of interrupt coverage collection area in words"
1940 KCOV uses preallocated per-cpu areas to collect coverage from
1941 soft interrupts. This specifies the size of those areas in the
1942 number of unsigned long words.
1944 menuconfig RUNTIME_TESTING_MENU
1945 bool "Runtime Testing"
1948 if RUNTIME_TESTING_MENU
1951 tristate "Linux Kernel Dump Test Tool Module"
1954 This module enables testing of the different dumping mechanisms by
1955 inducing system failures at predefined crash points.
1956 If you don't need it: say N
1957 Choose M here to compile this code as a module. The module will be
1960 Documentation on how to use the module can be found in
1961 Documentation/fault-injection/provoke-crashes.rst
1963 config TEST_LIST_SORT
1964 tristate "Linked list sorting test"
1965 depends on DEBUG_KERNEL || m
1967 Enable this to turn on 'list_sort()' function test. This test is
1968 executed only once during system boot (so affects only boot time),
1969 or at module load time.
1973 config TEST_MIN_HEAP
1974 tristate "Min heap test"
1975 depends on DEBUG_KERNEL || m
1977 Enable this to turn on min heap function tests. This test is
1978 executed only once during system boot (so affects only boot time),
1979 or at module load time.
1984 tristate "Array-based sort test"
1985 depends on DEBUG_KERNEL || m
1987 This option enables the self-test function of 'sort()' at boot,
1988 or at module load time.
1992 config KPROBES_SANITY_TEST
1993 bool "Kprobes sanity tests"
1994 depends on DEBUG_KERNEL
1997 This option provides for testing basic kprobes functionality on
1998 boot. Samples of kprobe and kretprobe are inserted and
1999 verified for functionality.
2001 Say N if you are unsure.
2003 config BACKTRACE_SELF_TEST
2004 tristate "Self test for the backtrace code"
2005 depends on DEBUG_KERNEL
2007 This option provides a kernel module that can be used to test
2008 the kernel stack backtrace code. This option is not useful
2009 for distributions or general kernels, but only for kernel
2010 developers working on architecture code.
2012 Note that if you want to also test saved backtraces, you will
2013 have to enable STACKTRACE as well.
2015 Say N if you are unsure.
2018 tristate "Red-Black tree test"
2019 depends on DEBUG_KERNEL
2021 A benchmark measuring the performance of the rbtree library.
2022 Also includes rbtree invariant checks.
2024 config REED_SOLOMON_TEST
2025 tristate "Reed-Solomon library test"
2026 depends on DEBUG_KERNEL || m
2028 select REED_SOLOMON_ENC16
2029 select REED_SOLOMON_DEC16
2031 This option enables the self-test function of rslib at boot,
2032 or at module load time.
2036 config INTERVAL_TREE_TEST
2037 tristate "Interval tree test"
2038 depends on DEBUG_KERNEL
2039 select INTERVAL_TREE
2041 A benchmark measuring the performance of the interval tree library
2044 tristate "Per cpu operations test"
2045 depends on m && DEBUG_KERNEL
2047 Enable this option to build test module which validates per-cpu
2052 config ATOMIC64_SELFTEST
2053 tristate "Perform an atomic64_t self-test"
2055 Enable this option to test the atomic64_t functions at boot or
2056 at module load time.
2060 config ASYNC_RAID6_TEST
2061 tristate "Self test for hardware accelerated raid6 recovery"
2062 depends on ASYNC_RAID6_RECOV
2065 This is a one-shot self test that permutes through the
2066 recovery of all the possible two disk failure scenarios for a
2067 N-disk array. Recovery is performed with the asynchronous
2068 raid6 recovery routines, and will optionally use an offload
2069 engine if one is available.
2074 tristate "Test functions located in the hexdump module at runtime"
2076 config TEST_STRING_HELPERS
2077 tristate "Test functions located in the string_helpers module at runtime"
2080 tristate "Test strscpy*() family of functions at runtime"
2083 tristate "Test kstrto*() family of functions at runtime"
2086 tristate "Test printf() family of functions at runtime"
2089 tristate "Test bitmap_*() family of functions at runtime"
2091 Enable this option to test the bitmap functions at boot.
2096 tristate "Test functions located in the uuid module at runtime"
2099 tristate "Test the XArray code at runtime"
2101 config TEST_OVERFLOW
2102 tristate "Test check_*_overflow() functions at runtime"
2104 config TEST_RHASHTABLE
2105 tristate "Perform selftest on resizable hash table"
2107 Enable this option to test the rhashtable functions at boot.
2112 tristate "Perform selftest on hash functions"
2114 Enable this option to test the kernel's integer (<linux/hash.h>),
2115 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
2116 hash functions on boot (or module load).
2118 This is intended to help people writing architecture-specific
2119 optimized versions. If unsure, say N.
2122 tristate "Perform selftest on IDA functions"
2125 tristate "Perform selftest on priority array manager"
2128 Enable this option to test priority array manager on boot
2133 config TEST_IRQ_TIMINGS
2134 bool "IRQ timings selftest"
2135 depends on IRQ_TIMINGS
2137 Enable this option to test the irq timings code on boot.
2142 tristate "Test module loading with 'hello world' module"
2145 This builds the "test_module" module that emits "Hello, world"
2146 on printk when loaded. It is designed to be used for basic
2147 evaluation of the module loading subsystem (for example when
2148 validating module verification). It lacks any extra dependencies,
2149 and will not normally be loaded by the system unless explicitly
2155 tristate "Test module for compilation of bitops operations"
2158 This builds the "test_bitops" module that is much like the
2159 TEST_LKM module except that it does a basic exercise of the
2160 set/clear_bit macros and get_count_order/long to make sure there are
2161 no compiler warnings from C=1 sparse checker or -Wextra
2162 compilations. It has no dependencies and doesn't run or load unless
2163 explicitly requested by name. for example: modprobe test_bitops.
2168 tristate "Test module for stress/performance analysis of vmalloc allocator"
2173 This builds the "test_vmalloc" module that should be used for
2174 stress and performance analysis. So, any new change for vmalloc
2175 subsystem can be evaluated from performance and stability point
2180 config TEST_USER_COPY
2181 tristate "Test user/kernel boundary protections"
2184 This builds the "test_user_copy" module that runs sanity checks
2185 on the copy_to/from_user infrastructure, making sure basic
2186 user/kernel boundary testing is working. If it fails to load,
2187 a regression has been detected in the user/kernel memory boundary
2193 tristate "Test BPF filter functionality"
2196 This builds the "test_bpf" module that runs various test vectors
2197 against the BPF interpreter or BPF JIT compiler depending on the
2198 current setting. This is in particular useful for BPF JIT compiler
2199 development, but also to run regression tests against changes in
2200 the interpreter code. It also enables test stubs for eBPF maps and
2201 verifier used by user space verifier testsuite.
2205 config TEST_BLACKHOLE_DEV
2206 tristate "Test blackhole netdev functionality"
2209 This builds the "test_blackhole_dev" module that validates the
2210 data path through this blackhole netdev.
2214 config FIND_BIT_BENCHMARK
2215 tristate "Test find_bit functions"
2217 This builds the "test_find_bit" module that measure find_*_bit()
2218 functions performance.
2222 config TEST_FIRMWARE
2223 tristate "Test firmware loading via userspace interface"
2224 depends on FW_LOADER
2226 This builds the "test_firmware" module that creates a userspace
2227 interface for testing firmware loading. This can be used to
2228 control the triggering of firmware loading without needing an
2229 actual firmware-using device. The contents can be rechecked by
2235 tristate "sysctl test driver"
2236 depends on PROC_SYSCTL
2238 This builds the "test_sysctl" module. This driver enables to test the
2239 proc sysctl interfaces available to drivers safely without affecting
2240 production knobs which might alter system functionality.
2244 config BITFIELD_KUNIT
2245 tristate "KUnit test bitfield functions at runtime"
2248 Enable this option to test the bitfield functions at boot.
2250 KUnit tests run during boot and output the results to the debug log
2251 in TAP format (http://testanything.org/). Only useful for kernel devs
2252 running the KUnit test harness, and not intended for inclusion into a
2255 For more information on KUnit and unit tests in general please refer
2256 to the KUnit documentation in Documentation/dev-tools/kunit/.
2260 config RESOURCE_KUNIT_TEST
2261 tristate "KUnit test for resource API"
2264 This builds the resource API unit test.
2265 Tests the logic of API provided by resource.c and ioport.h.
2266 For more information on KUnit and unit tests in general please refer
2267 to the KUnit documentation in Documentation/dev-tools/kunit/.
2271 config SYSCTL_KUNIT_TEST
2272 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2274 default KUNIT_ALL_TESTS
2276 This builds the proc sysctl unit test, which runs on boot.
2277 Tests the API contract and implementation correctness of sysctl.
2278 For more information on KUnit and unit tests in general please refer
2279 to the KUnit documentation in Documentation/dev-tools/kunit/.
2283 config LIST_KUNIT_TEST
2284 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2286 default KUNIT_ALL_TESTS
2288 This builds the linked list KUnit test suite.
2289 It tests that the API and basic functionality of the list_head type
2290 and associated macros.
2292 KUnit tests run during boot and output the results to the debug log
2293 in TAP format (https://testanything.org/). Only useful for kernel devs
2294 running the KUnit test harness, and not intended for inclusion into a
2297 For more information on KUnit and unit tests in general please refer
2298 to the KUnit documentation in Documentation/dev-tools/kunit/.
2302 config LINEAR_RANGES_TEST
2303 tristate "KUnit test for linear_ranges"
2305 select LINEAR_RANGES
2307 This builds the linear_ranges unit test, which runs on boot.
2308 Tests the linear_ranges logic correctness.
2309 For more information on KUnit and unit tests in general please refer
2310 to the KUnit documentation in Documentation/dev-tools/kunit/.
2314 config CMDLINE_KUNIT_TEST
2315 tristate "KUnit test for cmdline API"
2318 This builds the cmdline API unit test.
2319 Tests the logic of API provided by cmdline.c.
2320 For more information on KUnit and unit tests in general please refer
2321 to the KUnit documentation in Documentation/dev-tools/kunit/.
2326 tristate "KUnit test for bits.h"
2329 This builds the bits unit test.
2330 Tests the logic of macros defined in bits.h.
2331 For more information on KUnit and unit tests in general please refer
2332 to the KUnit documentation in Documentation/dev-tools/kunit/.
2337 tristate "udelay test driver"
2339 This builds the "udelay_test" module that helps to make sure
2340 that udelay() is working properly.
2344 config TEST_STATIC_KEYS
2345 tristate "Test static keys"
2348 Test the static key interfaces.
2353 tristate "kmod stress tester"
2355 depends on NETDEVICES && NET_CORE && INET # for TUN
2362 Test the kernel's module loading mechanism: kmod. kmod implements
2363 support to load modules using the Linux kernel's usermode helper.
2364 This test provides a series of tests against kmod.
2366 Although technically you can either build test_kmod as a module or
2367 into the kernel we disallow building it into the kernel since
2368 it stress tests request_module() and this will very likely cause
2369 some issues by taking over precious threads available from other
2370 module load requests, ultimately this could be fatal.
2374 tools/testing/selftests/kmod/kmod.sh --help
2378 config TEST_DEBUG_VIRTUAL
2379 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2380 depends on DEBUG_VIRTUAL
2382 Test the kernel's ability to detect incorrect calls to
2383 virt_to_phys() done against the non-linear part of the
2384 kernel's virtual address map.
2388 config TEST_MEMCAT_P
2389 tristate "Test memcat_p() helper function"
2391 Test the memcat_p() helper for correctly merging two
2392 pointer arrays together.
2396 config TEST_LIVEPATCH
2397 tristate "Test livepatching"
2399 depends on DYNAMIC_DEBUG
2400 depends on LIVEPATCH
2403 Test kernel livepatching features for correctness. The tests will
2404 load test modules that will be livepatched in various scenarios.
2406 To run all the livepatching tests:
2408 make -C tools/testing/selftests TARGETS=livepatch run_tests
2410 Alternatively, individual tests may be invoked:
2412 tools/testing/selftests/livepatch/test-callbacks.sh
2413 tools/testing/selftests/livepatch/test-livepatch.sh
2414 tools/testing/selftests/livepatch/test-shadow-vars.sh
2419 tristate "Perform selftest on object aggreration manager"
2423 Enable this option to test object aggregation manager on boot
2427 config TEST_STACKINIT
2428 tristate "Test level of stack variable initialization"
2430 Test if the kernel is zero-initializing stack variables and
2431 padding. Coverage is controlled by compiler flags,
2432 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2433 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2438 tristate "Test heap/page initialization"
2440 Test if the kernel is zero-initializing heap and page allocations.
2441 This can be useful to test init_on_alloc and init_on_free features.
2446 tristate "Test HMM (Heterogeneous Memory Management)"
2447 depends on TRANSPARENT_HUGEPAGE
2448 depends on DEVICE_PRIVATE
2452 This is a pseudo device driver solely for testing HMM.
2453 Say M here if you want to build the HMM test module.
2454 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2458 config TEST_FREE_PAGES
2459 tristate "Test freeing pages"
2461 Test that a memory leak does not occur due to a race between
2462 freeing a block of pages and a speculative page reference.
2463 Loading this module is safe if your kernel has the bug fixed.
2464 If the bug is not fixed, it will leak gigabytes of memory and
2465 probably OOM your system.
2468 tristate "Test floating point operations in kernel space"
2469 depends on X86 && !KCOV_INSTRUMENT_ALL
2471 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2472 which will trigger a sequence of floating point operations. This is used
2473 for self-testing floating point control register setting in
2478 endif # RUNTIME_TESTING_MENU
2483 This option adds a kernel parameter 'memtest', which allows memtest
2485 memtest=0, mean disabled; -- default
2486 memtest=1, mean do 1 test pattern;
2488 memtest=17, mean do 17 test patterns.
2489 If you are unsure how to answer this question, answer N.
2493 config HYPERV_TESTING
2494 bool "Microsoft Hyper-V driver testing"
2496 depends on HYPERV && DEBUG_FS
2498 Select this option to enable Hyper-V vmbus testing.
2500 endmenu # "Kernel Testing and Coverage"
2502 source "Documentation/Kconfig"
2504 endmenu # Kernel hacking
projects / linux-2.6-microblaze.git / blob