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
288 depends on CC_IS_GCC || $(success,$(srctree)/scripts/test_dwarf5_support.sh $(CC) $(CLANG_FLAGS))
289 depends on !DEBUG_INFO_BTF
291 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
292 5.0+ accepts the -gdwarf-5 flag but only had partial support for some
293 draft features until 7.0), and gdb 8.0+.
295 Changes to the structure of debug info in Version 5 allow for around
296 15-18% savings in resulting image and debug info section sizes as
297 compared to DWARF Version 4. DWARF Version 5 standardizes previous
298 extensions such as accelerators for symbol indexing and the format
299 for fission (.dwo/.dwp) files. Users may not want to select this
300 config if they rely on tooling that has not yet been updated to
301 support DWARF Version 5.
303 endchoice # "DWARF version"
305 config DEBUG_INFO_BTF
306 bool "Generate BTF typeinfo"
307 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
308 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
310 Generate deduplicated BTF type information from DWARF debug info.
311 Turning this on expects presence of pahole tool, which will convert
312 DWARF type info into equivalent deduplicated BTF type info.
314 config PAHOLE_HAS_SPLIT_BTF
315 def_bool $(success, test `$(PAHOLE) --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/'` -ge "119")
317 config DEBUG_INFO_BTF_MODULES
319 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
321 Generate compact split BTF type information for kernel modules.
324 bool "Provide GDB scripts for kernel debugging"
326 This creates the required links to GDB helper scripts in the
327 build directory. If you load vmlinux into gdb, the helper
328 scripts will be automatically imported by gdb as well, and
329 additional functions are available to analyze a Linux kernel
330 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
336 int "Warn for stack frames larger than"
338 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
339 default 1280 if (!64BIT && PARISC)
340 default 1024 if (!64BIT && !PARISC)
341 default 2048 if 64BIT
343 Tell gcc to warn at build time for stack frames larger than this.
344 Setting this too low will cause a lot of warnings.
345 Setting it to 0 disables the warning.
347 config STRIP_ASM_SYMS
348 bool "Strip assembler-generated symbols during link"
351 Strip internal assembler-generated symbols during a link (symbols
352 that look like '.Lxxx') so they don't pollute the output of
353 get_wchan() and suchlike.
356 bool "Generate readable assembler code"
357 depends on DEBUG_KERNEL
359 Disable some compiler optimizations that tend to generate human unreadable
360 assembler output. This may make the kernel slightly slower, but it helps
361 to keep kernel developers who have to stare a lot at assembler listings
364 config HEADERS_INSTALL
365 bool "Install uapi headers to usr/include"
368 This option will install uapi headers (headers exported to user-space)
369 into the usr/include directory for use during the kernel build.
370 This is unneeded for building the kernel itself, but needed for some
371 user-space program samples. It is also needed by some features such
372 as uapi header sanity checks.
374 config DEBUG_SECTION_MISMATCH
375 bool "Enable full Section mismatch analysis"
377 The section mismatch analysis checks if there are illegal
378 references from one section to another section.
379 During linktime or runtime, some sections are dropped;
380 any use of code/data previously in these sections would
381 most likely result in an oops.
382 In the code, functions and variables are annotated with
383 __init,, etc. (see the full list in include/linux/init.h),
384 which results in the code/data being placed in specific sections.
385 The section mismatch analysis is always performed after a full
386 kernel build, and enabling this option causes the following
387 additional step to occur:
388 - Add the option -fno-inline-functions-called-once to gcc commands.
389 When inlining a function annotated with __init in a non-init
390 function, we would lose the section information and thus
391 the analysis would not catch the illegal reference.
392 This option tells gcc to inline less (but it does result in
395 config SECTION_MISMATCH_WARN_ONLY
396 bool "Make section mismatch errors non-fatal"
399 If you say N here, the build process will fail if there are any
400 section mismatch, instead of just throwing warnings.
404 config DEBUG_FORCE_FUNCTION_ALIGN_32B
405 bool "Force all function address 32B aligned" if EXPERT
407 There are cases that a commit from one domain changes the function
408 address alignment of other domains, and cause magic performance
409 bump (regression or improvement). Enable this option will help to
410 verify if the bump is caused by function alignment changes, while
411 it will slightly increase the kernel size and affect icache usage.
413 It is mainly for debug and performance tuning use.
416 # Select this config option from the architecture Kconfig, if it
417 # is preferred to always offer frame pointers as a config
418 # option on the architecture (regardless of KERNEL_DEBUG):
420 config ARCH_WANT_FRAME_POINTERS
424 bool "Compile the kernel with frame pointers"
425 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
426 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
428 If you say Y here the resulting kernel image will be slightly
429 larger and slower, but it gives very useful debugging information
430 in case of kernel bugs. (precise oopses/stacktraces/warnings)
432 config STACK_VALIDATION
433 bool "Compile-time stack metadata validation"
434 depends on HAVE_STACK_VALIDATION
437 Add compile-time checks to validate stack metadata, including frame
438 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
439 that runtime stack traces are more reliable.
441 This is also a prerequisite for generation of ORC unwind data, which
442 is needed for CONFIG_UNWINDER_ORC.
444 For more information, see
445 tools/objtool/Documentation/stack-validation.txt.
447 config VMLINUX_VALIDATION
449 depends on STACK_VALIDATION && DEBUG_ENTRY && !PARAVIRT
452 config DEBUG_FORCE_WEAK_PER_CPU
453 bool "Force weak per-cpu definitions"
454 depends on DEBUG_KERNEL
456 s390 and alpha require percpu variables in modules to be
457 defined weak to work around addressing range issue which
458 puts the following two restrictions on percpu variable
461 1. percpu symbols must be unique whether static or not
462 2. percpu variables can't be defined inside a function
464 To ensure that generic code follows the above rules, this
465 option forces all percpu variables to be defined as weak.
467 endmenu # "Compiler options"
469 menu "Generic Kernel Debugging Instruments"
472 bool "Magic SysRq key"
475 If you say Y here, you will have some control over the system even
476 if the system crashes for example during kernel debugging (e.g., you
477 will be able to flush the buffer cache to disk, reboot the system
478 immediately or dump some status information). This is accomplished
479 by pressing various keys while holding SysRq (Alt+PrintScreen). It
480 also works on a serial console (on PC hardware at least), if you
481 send a BREAK and then within 5 seconds a command keypress. The
482 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
483 Don't say Y unless you really know what this hack does.
485 config MAGIC_SYSRQ_DEFAULT_ENABLE
486 hex "Enable magic SysRq key functions by default"
487 depends on MAGIC_SYSRQ
490 Specifies which SysRq key functions are enabled by default.
491 This may be set to 1 or 0 to enable or disable them all, or
492 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
494 config MAGIC_SYSRQ_SERIAL
495 bool "Enable magic SysRq key over serial"
496 depends on MAGIC_SYSRQ
499 Many embedded boards have a disconnected TTL level serial which can
500 generate some garbage that can lead to spurious false sysrq detects.
501 This option allows you to decide whether you want to enable the
504 config MAGIC_SYSRQ_SERIAL_SEQUENCE
505 string "Char sequence that enables magic SysRq over serial"
506 depends on MAGIC_SYSRQ_SERIAL
509 Specifies a sequence of characters that can follow BREAK to enable
510 SysRq on a serial console.
512 If unsure, leave an empty string and the option will not be enabled.
515 bool "Debug Filesystem"
517 debugfs is a virtual file system that kernel developers use to put
518 debugging files into. Enable this option to be able to read and
519 write to these files.
521 For detailed documentation on the debugfs API, see
522 Documentation/filesystems/.
527 prompt "Debugfs default access"
529 default DEBUG_FS_ALLOW_ALL
531 This selects the default access restrictions for debugfs.
532 It can be overridden with kernel command line option
533 debugfs=[on,no-mount,off]. The restrictions apply for API access
534 and filesystem registration.
536 config DEBUG_FS_ALLOW_ALL
539 No restrictions apply. Both API and filesystem registration
540 is on. This is the normal default operation.
542 config DEBUG_FS_DISALLOW_MOUNT
543 bool "Do not register debugfs as filesystem"
545 The API is open but filesystem is not loaded. Clients can still do
546 their work and read with debug tools that do not need
549 config DEBUG_FS_ALLOW_NONE
552 Access is off. Clients get -PERM when trying to create nodes in
553 debugfs tree and debugfs is not registered as a filesystem.
554 Client can then back-off or continue without debugfs access.
558 source "lib/Kconfig.kgdb"
559 source "lib/Kconfig.ubsan"
560 source "lib/Kconfig.kcsan"
565 bool "Kernel debugging"
567 Say Y here if you are developing drivers or trying to debug and
568 identify kernel problems.
571 bool "Miscellaneous debug code"
573 depends on DEBUG_KERNEL
575 Say Y here if you need to enable miscellaneous debug code that should
576 be under a more specific debug option but isn't.
579 menu "Memory Debugging"
581 source "mm/Kconfig.debug"
584 bool "Debug object operations"
585 depends on DEBUG_KERNEL
587 If you say Y here, additional code will be inserted into the
588 kernel to track the life time of various objects and validate
589 the operations on those objects.
591 config DEBUG_OBJECTS_SELFTEST
592 bool "Debug objects selftest"
593 depends on DEBUG_OBJECTS
595 This enables the selftest of the object debug code.
597 config DEBUG_OBJECTS_FREE
598 bool "Debug objects in freed memory"
599 depends on DEBUG_OBJECTS
601 This enables checks whether a k/v free operation frees an area
602 which contains an object which has not been deactivated
603 properly. This can make kmalloc/kfree-intensive workloads
606 config DEBUG_OBJECTS_TIMERS
607 bool "Debug timer objects"
608 depends on DEBUG_OBJECTS
610 If you say Y here, additional code will be inserted into the
611 timer routines to track the life time of timer objects and
612 validate the timer operations.
614 config DEBUG_OBJECTS_WORK
615 bool "Debug work objects"
616 depends on DEBUG_OBJECTS
618 If you say Y here, additional code will be inserted into the
619 work queue routines to track the life time of work objects and
620 validate the work operations.
622 config DEBUG_OBJECTS_RCU_HEAD
623 bool "Debug RCU callbacks objects"
624 depends on DEBUG_OBJECTS
626 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
628 config DEBUG_OBJECTS_PERCPU_COUNTER
629 bool "Debug percpu counter objects"
630 depends on DEBUG_OBJECTS
632 If you say Y here, additional code will be inserted into the
633 percpu counter routines to track the life time of percpu counter
634 objects and validate the percpu counter operations.
636 config DEBUG_OBJECTS_ENABLE_DEFAULT
637 int "debug_objects bootup default value (0-1)"
640 depends on DEBUG_OBJECTS
642 Debug objects boot parameter default value
645 bool "Debug slab memory allocations"
646 depends on DEBUG_KERNEL && SLAB
648 Say Y here to have the kernel do limited verification on memory
649 allocation as well as poisoning memory on free to catch use of freed
650 memory. This can make kmalloc/kfree-intensive workloads much slower.
653 bool "SLUB debugging on by default"
654 depends on SLUB && SLUB_DEBUG
657 Boot with debugging on by default. SLUB boots by default with
658 the runtime debug capabilities switched off. Enabling this is
659 equivalent to specifying the "slub_debug" parameter on boot.
660 There is no support for more fine grained debug control like
661 possible with slub_debug=xxx. SLUB debugging may be switched
662 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
667 bool "Enable SLUB performance statistics"
668 depends on SLUB && SYSFS
670 SLUB statistics are useful to debug SLUBs allocation behavior in
671 order find ways to optimize the allocator. This should never be
672 enabled for production use since keeping statistics slows down
673 the allocator by a few percentage points. The slabinfo command
674 supports the determination of the most active slabs to figure
675 out which slabs are relevant to a particular load.
676 Try running: slabinfo -DA
678 config HAVE_DEBUG_KMEMLEAK
681 config DEBUG_KMEMLEAK
682 bool "Kernel memory leak detector"
683 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
685 select STACKTRACE if STACKTRACE_SUPPORT
689 Say Y here if you want to enable the memory leak
690 detector. The memory allocation/freeing is traced in a way
691 similar to the Boehm's conservative garbage collector, the
692 difference being that the orphan objects are not freed but
693 only shown in /sys/kernel/debug/kmemleak. Enabling this
694 feature will introduce an overhead to memory
695 allocations. See Documentation/dev-tools/kmemleak.rst for more
698 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
699 of finding leaks due to the slab objects poisoning.
701 In order to access the kmemleak file, debugfs needs to be
702 mounted (usually at /sys/kernel/debug).
704 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
705 int "Kmemleak memory pool size"
706 depends on DEBUG_KMEMLEAK
710 Kmemleak must track all the memory allocations to avoid
711 reporting false positives. Since memory may be allocated or
712 freed before kmemleak is fully initialised, use a static pool
713 of metadata objects to track such callbacks. After kmemleak is
714 fully initialised, this memory pool acts as an emergency one
715 if slab allocations fail.
717 config DEBUG_KMEMLEAK_TEST
718 tristate "Simple test for the kernel memory leak detector"
719 depends on DEBUG_KMEMLEAK && m
721 This option enables a module that explicitly leaks memory.
725 config DEBUG_KMEMLEAK_DEFAULT_OFF
726 bool "Default kmemleak to off"
727 depends on DEBUG_KMEMLEAK
729 Say Y here to disable kmemleak by default. It can then be enabled
730 on the command line via kmemleak=on.
732 config DEBUG_KMEMLEAK_AUTO_SCAN
733 bool "Enable kmemleak auto scan thread on boot up"
735 depends on DEBUG_KMEMLEAK
737 Depending on the cpu, kmemleak scan may be cpu intensive and can
738 stall user tasks at times. This option enables/disables automatic
739 kmemleak scan at boot up.
741 Say N here to disable kmemleak auto scan thread to stop automatic
742 scanning. Disabling this option disables automatic reporting of
747 config DEBUG_STACK_USAGE
748 bool "Stack utilization instrumentation"
749 depends on DEBUG_KERNEL && !IA64
751 Enables the display of the minimum amount of free stack which each
752 task has ever had available in the sysrq-T and sysrq-P debug output.
754 This option will slow down process creation somewhat.
756 config SCHED_STACK_END_CHECK
757 bool "Detect stack corruption on calls to schedule()"
758 depends on DEBUG_KERNEL
761 This option checks for a stack overrun on calls to schedule().
762 If the stack end location is found to be over written always panic as
763 the content of the corrupted region can no longer be trusted.
764 This is to ensure no erroneous behaviour occurs which could result in
765 data corruption or a sporadic crash at a later stage once the region
766 is examined. The runtime overhead introduced is minimal.
768 config ARCH_HAS_DEBUG_VM_PGTABLE
771 An architecture should select this when it can successfully
772 build and run DEBUG_VM_PGTABLE.
776 depends on DEBUG_KERNEL
778 Enable this to turn on extended checks in the virtual-memory system
779 that may impact performance.
783 config DEBUG_VM_VMACACHE
784 bool "Debug VMA caching"
787 Enable this to turn on VMA caching debug information. Doing so
788 can cause significant overhead, so only enable it in non-production
794 bool "Debug VM red-black trees"
797 Enable VM red-black tree debugging information and extra validations.
801 config DEBUG_VM_PGFLAGS
802 bool "Debug page-flags operations"
805 Enables extra validation on page flags operations.
809 config DEBUG_VM_PGTABLE
810 bool "Debug arch page table for semantics compliance"
812 depends on ARCH_HAS_DEBUG_VM_PGTABLE
813 default y if DEBUG_VM
815 This option provides a debug method which can be used to test
816 architecture page table helper functions on various platforms in
817 verifying if they comply with expected generic MM semantics. This
818 will help architecture code in making sure that any changes or
819 new additions of these helpers still conform to expected
820 semantics of the generic MM. Platforms will have to opt in for
821 this through ARCH_HAS_DEBUG_VM_PGTABLE.
825 config ARCH_HAS_DEBUG_VIRTUAL
829 bool "Debug VM translations"
830 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
832 Enable some costly sanity checks in virtual to page code. This can
833 catch mistakes with virt_to_page() and friends.
837 config DEBUG_NOMMU_REGIONS
838 bool "Debug the global anon/private NOMMU mapping region tree"
839 depends on DEBUG_KERNEL && !MMU
841 This option causes the global tree of anonymous and private mapping
842 regions to be regularly checked for invalid topology.
844 config DEBUG_MEMORY_INIT
845 bool "Debug memory initialisation" if EXPERT
848 Enable this for additional checks during memory initialisation.
849 The sanity checks verify aspects of the VM such as the memory model
850 and other information provided by the architecture. Verbose
851 information will be printed at KERN_DEBUG loglevel depending
852 on the mminit_loglevel= command-line option.
856 config MEMORY_NOTIFIER_ERROR_INJECT
857 tristate "Memory hotplug notifier error injection module"
858 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
860 This option provides the ability to inject artificial errors to
861 memory hotplug notifier chain callbacks. It is controlled through
862 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
864 If the notifier call chain should be failed with some events
865 notified, write the error code to "actions/<notifier event>/error".
867 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
869 # cd /sys/kernel/debug/notifier-error-inject/memory
870 # echo -12 > actions/MEM_GOING_OFFLINE/error
871 # echo offline > /sys/devices/system/memory/memoryXXX/state
872 bash: echo: write error: Cannot allocate memory
874 To compile this code as a module, choose M here: the module will
875 be called memory-notifier-error-inject.
879 config DEBUG_PER_CPU_MAPS
880 bool "Debug access to per_cpu maps"
881 depends on DEBUG_KERNEL
884 Say Y to verify that the per_cpu map being accessed has
885 been set up. This adds a fair amount of code to kernel memory
886 and decreases performance.
890 config DEBUG_KMAP_LOCAL
891 bool "Debug kmap_local temporary mappings"
892 depends on DEBUG_KERNEL && KMAP_LOCAL
894 This option enables additional error checking for the kmap_local
895 infrastructure. Disable for production use.
897 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
900 config DEBUG_KMAP_LOCAL_FORCE_MAP
901 bool "Enforce kmap_local temporary mappings"
902 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
904 select DEBUG_KMAP_LOCAL
906 This option enforces temporary mappings through the kmap_local
907 mechanism for non-highmem pages and on non-highmem systems.
908 Disable this for production systems!
911 bool "Highmem debugging"
912 depends on DEBUG_KERNEL && HIGHMEM
913 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
914 select DEBUG_KMAP_LOCAL
916 This option enables additional error checking for high memory
917 systems. Disable for production systems.
919 config HAVE_DEBUG_STACKOVERFLOW
922 config DEBUG_STACKOVERFLOW
923 bool "Check for stack overflows"
924 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
926 Say Y here if you want to check for overflows of kernel, IRQ
927 and exception stacks (if your architecture uses them). This
928 option will show detailed messages if free stack space drops
929 below a certain limit.
931 These kinds of bugs usually occur when call-chains in the
932 kernel get too deep, especially when interrupts are
935 Use this in cases where you see apparently random memory
936 corruption, especially if it appears in 'struct thread_info'
938 If in doubt, say "N".
940 source "lib/Kconfig.kasan"
942 endmenu # "Memory Debugging"
945 bool "Debug shared IRQ handlers"
946 depends on DEBUG_KERNEL
948 Enable this to generate a spurious interrupt just before a shared
949 interrupt handler is deregistered (generating one when registering
950 is currently disabled). Drivers need to handle this correctly. Some
951 don't and need to be caught.
953 menu "Debug Oops, Lockups and Hangs"
958 Say Y here to enable the kernel to panic when it oopses. This
959 has the same effect as setting oops=panic on the kernel command
962 This feature is useful to ensure that the kernel does not do
963 anything erroneous after an oops which could result in data
964 corruption or other issues.
968 config PANIC_ON_OOPS_VALUE
971 default 0 if !PANIC_ON_OOPS
972 default 1 if PANIC_ON_OOPS
978 Set the timeout value (in seconds) until a reboot occurs when
979 the kernel panics. If n = 0, then we wait forever. A timeout
980 value n > 0 will wait n seconds before rebooting, while a timeout
981 value n < 0 will reboot immediately.
983 config LOCKUP_DETECTOR
986 config SOFTLOCKUP_DETECTOR
987 bool "Detect Soft Lockups"
988 depends on DEBUG_KERNEL && !S390
989 select LOCKUP_DETECTOR
991 Say Y here to enable the kernel to act as a watchdog to detect
994 Softlockups are bugs that cause the kernel to loop in kernel
995 mode for more than 20 seconds, without giving other tasks a
996 chance to run. The current stack trace is displayed upon
997 detection and the system will stay locked up.
999 config BOOTPARAM_SOFTLOCKUP_PANIC
1000 bool "Panic (Reboot) On Soft Lockups"
1001 depends on SOFTLOCKUP_DETECTOR
1003 Say Y here to enable the kernel to panic on "soft lockups",
1004 which are bugs that cause the kernel to loop in kernel
1005 mode for more than 20 seconds (configurable using the watchdog_thresh
1006 sysctl), without giving other tasks a chance to run.
1008 The panic can be used in combination with panic_timeout,
1009 to cause the system to reboot automatically after a
1010 lockup has been detected. This feature is useful for
1011 high-availability systems that have uptime guarantees and
1012 where a lockup must be resolved ASAP.
1016 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
1018 depends on SOFTLOCKUP_DETECTOR
1020 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
1021 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
1023 config HARDLOCKUP_DETECTOR_PERF
1025 select SOFTLOCKUP_DETECTOR
1028 # Enables a timestamp based low pass filter to compensate for perf based
1029 # hard lockup detection which runs too fast due to turbo modes.
1031 config HARDLOCKUP_CHECK_TIMESTAMP
1035 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1036 # lockup detector rather than the perf based detector.
1038 config HARDLOCKUP_DETECTOR
1039 bool "Detect Hard Lockups"
1040 depends on DEBUG_KERNEL && !S390
1041 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1042 select LOCKUP_DETECTOR
1043 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1044 select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH
1046 Say Y here to enable the kernel to act as a watchdog to detect
1049 Hardlockups are bugs that cause the CPU to loop in kernel mode
1050 for more than 10 seconds, without letting other interrupts have a
1051 chance to run. The current stack trace is displayed upon detection
1052 and the system will stay locked up.
1054 config BOOTPARAM_HARDLOCKUP_PANIC
1055 bool "Panic (Reboot) On Hard Lockups"
1056 depends on HARDLOCKUP_DETECTOR
1058 Say Y here to enable the kernel to panic on "hard lockups",
1059 which are bugs that cause the kernel to loop in kernel
1060 mode with interrupts disabled for more than 10 seconds (configurable
1061 using the watchdog_thresh sysctl).
1065 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
1067 depends on HARDLOCKUP_DETECTOR
1069 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
1070 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
1072 config DETECT_HUNG_TASK
1073 bool "Detect Hung Tasks"
1074 depends on DEBUG_KERNEL
1075 default SOFTLOCKUP_DETECTOR
1077 Say Y here to enable the kernel to detect "hung tasks",
1078 which are bugs that cause the task to be stuck in
1079 uninterruptible "D" state indefinitely.
1081 When a hung task is detected, the kernel will print the
1082 current stack trace (which you should report), but the
1083 task will stay in uninterruptible state. If lockdep is
1084 enabled then all held locks will also be reported. This
1085 feature has negligible overhead.
1087 config DEFAULT_HUNG_TASK_TIMEOUT
1088 int "Default timeout for hung task detection (in seconds)"
1089 depends on DETECT_HUNG_TASK
1092 This option controls the default timeout (in seconds) used
1093 to determine when a task has become non-responsive and should
1096 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1097 sysctl or by writing a value to
1098 /proc/sys/kernel/hung_task_timeout_secs.
1100 A timeout of 0 disables the check. The default is two minutes.
1101 Keeping the default should be fine in most cases.
1103 config BOOTPARAM_HUNG_TASK_PANIC
1104 bool "Panic (Reboot) On Hung Tasks"
1105 depends on DETECT_HUNG_TASK
1107 Say Y here to enable the kernel to panic on "hung tasks",
1108 which are bugs that cause the kernel to leave a task stuck
1109 in uninterruptible "D" state.
1111 The panic can be used in combination with panic_timeout,
1112 to cause the system to reboot automatically after a
1113 hung task has been detected. This feature is useful for
1114 high-availability systems that have uptime guarantees and
1115 where a hung tasks must be resolved ASAP.
1119 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
1121 depends on DETECT_HUNG_TASK
1123 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
1124 default 1 if BOOTPARAM_HUNG_TASK_PANIC
1127 bool "Detect Workqueue Stalls"
1128 depends on DEBUG_KERNEL
1130 Say Y here to enable stall detection on workqueues. If a
1131 worker pool doesn't make forward progress on a pending work
1132 item for over a given amount of time, 30s by default, a
1133 warning message is printed along with dump of workqueue
1134 state. This can be configured through kernel parameter
1135 "workqueue.watchdog_thresh" and its sysfs counterpart.
1138 tristate "Test module to generate lockups"
1141 This builds the "test_lockup" module that helps to make sure
1142 that watchdogs and lockup detectors are working properly.
1144 Depending on module parameters it could emulate soft or hard
1145 lockup, "hung task", or locking arbitrary lock for a long time.
1146 Also it could generate series of lockups with cooling-down periods.
1150 endmenu # "Debug lockups and hangs"
1152 menu "Scheduler Debugging"
1155 bool "Collect scheduler debugging info"
1156 depends on DEBUG_KERNEL && PROC_FS
1159 If you say Y here, the /proc/sched_debug file will be provided
1160 that can help debug the scheduler. The runtime overhead of this
1168 bool "Collect scheduler statistics"
1169 depends on DEBUG_KERNEL && PROC_FS
1172 If you say Y here, additional code will be inserted into the
1173 scheduler and related routines to collect statistics about
1174 scheduler behavior and provide them in /proc/schedstat. These
1175 stats may be useful for both tuning and debugging the scheduler
1176 If you aren't debugging the scheduler or trying to tune a specific
1177 application, you can say N to avoid the very slight overhead
1182 config DEBUG_TIMEKEEPING
1183 bool "Enable extra timekeeping sanity checking"
1185 This option will enable additional timekeeping sanity checks
1186 which may be helpful when diagnosing issues where timekeeping
1187 problems are suspected.
1189 This may include checks in the timekeeping hotpaths, so this
1190 option may have a (very small) performance impact to some
1195 config DEBUG_PREEMPT
1196 bool "Debug preemptible kernel"
1197 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1200 If you say Y here then the kernel will use a debug variant of the
1201 commonly used smp_processor_id() function and will print warnings
1202 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1203 will detect preemption count underflows.
1205 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1207 config LOCK_DEBUGGING_SUPPORT
1209 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1212 config PROVE_LOCKING
1213 bool "Lock debugging: prove locking correctness"
1214 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1216 select DEBUG_SPINLOCK
1217 select DEBUG_MUTEXES
1218 select DEBUG_RT_MUTEXES if RT_MUTEXES
1220 select DEBUG_WW_MUTEX_SLOWPATH
1221 select DEBUG_LOCK_ALLOC
1222 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1223 select TRACE_IRQFLAGS
1226 This feature enables the kernel to prove that all locking
1227 that occurs in the kernel runtime is mathematically
1228 correct: that under no circumstance could an arbitrary (and
1229 not yet triggered) combination of observed locking
1230 sequences (on an arbitrary number of CPUs, running an
1231 arbitrary number of tasks and interrupt contexts) cause a
1234 In short, this feature enables the kernel to report locking
1235 related deadlocks before they actually occur.
1237 The proof does not depend on how hard and complex a
1238 deadlock scenario would be to trigger: how many
1239 participant CPUs, tasks and irq-contexts would be needed
1240 for it to trigger. The proof also does not depend on
1241 timing: if a race and a resulting deadlock is possible
1242 theoretically (no matter how unlikely the race scenario
1243 is), it will be proven so and will immediately be
1244 reported by the kernel (once the event is observed that
1245 makes the deadlock theoretically possible).
1247 If a deadlock is impossible (i.e. the locking rules, as
1248 observed by the kernel, are mathematically correct), the
1249 kernel reports nothing.
1251 NOTE: this feature can also be enabled for rwlocks, mutexes
1252 and rwsems - in which case all dependencies between these
1253 different locking variants are observed and mapped too, and
1254 the proof of observed correctness is also maintained for an
1255 arbitrary combination of these separate locking variants.
1257 For more details, see Documentation/locking/lockdep-design.rst.
1259 config PROVE_RAW_LOCK_NESTING
1260 bool "Enable raw_spinlock - spinlock nesting checks"
1261 depends on PROVE_LOCKING
1264 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1265 that the lock nesting rules for PREEMPT_RT enabled kernels are
1268 NOTE: There are known nesting problems. So if you enable this
1269 option expect lockdep splats until these problems have been fully
1270 addressed which is work in progress. This config switch allows to
1271 identify and analyze these problems. It will be removed and the
1272 check permanentely enabled once the main issues have been fixed.
1274 If unsure, select N.
1277 bool "Lock usage statistics"
1278 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1280 select DEBUG_SPINLOCK
1281 select DEBUG_MUTEXES
1282 select DEBUG_RT_MUTEXES if RT_MUTEXES
1283 select DEBUG_LOCK_ALLOC
1286 This feature enables tracking lock contention points
1288 For more details, see Documentation/locking/lockstat.rst
1290 This also enables lock events required by "perf lock",
1292 If you want to use "perf lock", you also need to turn on
1293 CONFIG_EVENT_TRACING.
1295 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1296 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1298 config DEBUG_RT_MUTEXES
1299 bool "RT Mutex debugging, deadlock detection"
1300 depends on DEBUG_KERNEL && RT_MUTEXES
1302 This allows rt mutex semantics violations and rt mutex related
1303 deadlocks (lockups) to be detected and reported automatically.
1305 config DEBUG_SPINLOCK
1306 bool "Spinlock and rw-lock debugging: basic checks"
1307 depends on DEBUG_KERNEL
1308 select UNINLINE_SPIN_UNLOCK
1310 Say Y here and build SMP to catch missing spinlock initialization
1311 and certain other kinds of spinlock errors commonly made. This is
1312 best used in conjunction with the NMI watchdog so that spinlock
1313 deadlocks are also debuggable.
1315 config DEBUG_MUTEXES
1316 bool "Mutex debugging: basic checks"
1317 depends on DEBUG_KERNEL
1319 This feature allows mutex semantics violations to be detected and
1322 config DEBUG_WW_MUTEX_SLOWPATH
1323 bool "Wait/wound mutex debugging: Slowpath testing"
1324 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1325 select DEBUG_LOCK_ALLOC
1326 select DEBUG_SPINLOCK
1327 select DEBUG_MUTEXES
1329 This feature enables slowpath testing for w/w mutex users by
1330 injecting additional -EDEADLK wound/backoff cases. Together with
1331 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1332 will test all possible w/w mutex interface abuse with the
1333 exception of simply not acquiring all the required locks.
1334 Note that this feature can introduce significant overhead, so
1335 it really should not be enabled in a production or distro kernel,
1336 even a debug kernel. If you are a driver writer, enable it. If
1337 you are a distro, do not.
1340 bool "RW Semaphore debugging: basic checks"
1341 depends on DEBUG_KERNEL
1343 This debugging feature allows mismatched rw semaphore locks
1344 and unlocks to be detected and reported.
1346 config DEBUG_LOCK_ALLOC
1347 bool "Lock debugging: detect incorrect freeing of live locks"
1348 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1349 select DEBUG_SPINLOCK
1350 select DEBUG_MUTEXES
1351 select DEBUG_RT_MUTEXES if RT_MUTEXES
1354 This feature will check whether any held lock (spinlock, rwlock,
1355 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1356 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1357 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1358 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1359 held during task exit.
1363 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1365 select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86
1369 config LOCKDEP_SMALL
1372 config DEBUG_LOCKDEP
1373 bool "Lock dependency engine debugging"
1374 depends on DEBUG_KERNEL && LOCKDEP
1375 select DEBUG_IRQFLAGS
1377 If you say Y here, the lock dependency engine will do
1378 additional runtime checks to debug itself, at the price
1379 of more runtime overhead.
1381 config DEBUG_ATOMIC_SLEEP
1382 bool "Sleep inside atomic section checking"
1383 select PREEMPT_COUNT
1384 depends on DEBUG_KERNEL
1385 depends on !ARCH_NO_PREEMPT
1387 If you say Y here, various routines which may sleep will become very
1388 noisy if they are called inside atomic sections: when a spinlock is
1389 held, inside an rcu read side critical section, inside preempt disabled
1390 sections, inside an interrupt, etc...
1392 config DEBUG_LOCKING_API_SELFTESTS
1393 bool "Locking API boot-time self-tests"
1394 depends on DEBUG_KERNEL
1396 Say Y here if you want the kernel to run a short self-test during
1397 bootup. The self-test checks whether common types of locking bugs
1398 are detected by debugging mechanisms or not. (if you disable
1399 lock debugging then those bugs wont be detected of course.)
1400 The following locking APIs are covered: spinlocks, rwlocks,
1403 config LOCK_TORTURE_TEST
1404 tristate "torture tests for locking"
1405 depends on DEBUG_KERNEL
1408 This option provides a kernel module that runs torture tests
1409 on kernel locking primitives. The kernel module may be built
1410 after the fact on the running kernel to be tested, if desired.
1412 Say Y here if you want kernel locking-primitive torture tests
1413 to be built into the kernel.
1414 Say M if you want these torture tests to build as a module.
1415 Say N if you are unsure.
1417 config WW_MUTEX_SELFTEST
1418 tristate "Wait/wound mutex selftests"
1420 This option provides a kernel module that runs tests on the
1421 on the struct ww_mutex locking API.
1423 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1424 with this test harness.
1426 Say M if you want these self tests to build as a module.
1427 Say N if you are unsure.
1429 config SCF_TORTURE_TEST
1430 tristate "torture tests for smp_call_function*()"
1431 depends on DEBUG_KERNEL
1434 This option provides a kernel module that runs torture tests
1435 on the smp_call_function() family of primitives. The kernel
1436 module may be built after the fact on the running kernel to
1437 be tested, if desired.
1439 config CSD_LOCK_WAIT_DEBUG
1440 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1441 depends on DEBUG_KERNEL
1445 This option enables debug prints when CPUs are slow to respond
1446 to the smp_call_function*() IPI wrappers. These debug prints
1447 include the IPI handler function currently executing (if any)
1448 and relevant stack traces.
1450 endmenu # lock debugging
1452 config TRACE_IRQFLAGS
1453 depends on TRACE_IRQFLAGS_SUPPORT
1456 Enables hooks to interrupt enabling and disabling for
1457 either tracing or lock debugging.
1459 config TRACE_IRQFLAGS_NMI
1461 depends on TRACE_IRQFLAGS
1462 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1464 config DEBUG_IRQFLAGS
1465 bool "Debug IRQ flag manipulation"
1467 Enables checks for potentially unsafe enabling or disabling of
1468 interrupts, such as calling raw_local_irq_restore() when interrupts
1472 bool "Stack backtrace support"
1473 depends on STACKTRACE_SUPPORT
1475 This option causes the kernel to create a /proc/pid/stack for
1476 every process, showing its current stack trace.
1477 It is also used by various kernel debugging features that require
1478 stack trace generation.
1480 config WARN_ALL_UNSEEDED_RANDOM
1481 bool "Warn for all uses of unseeded randomness"
1484 Some parts of the kernel contain bugs relating to their use of
1485 cryptographically secure random numbers before it's actually possible
1486 to generate those numbers securely. This setting ensures that these
1487 flaws don't go unnoticed, by enabling a message, should this ever
1488 occur. This will allow people with obscure setups to know when things
1489 are going wrong, so that they might contact developers about fixing
1492 Unfortunately, on some models of some architectures getting
1493 a fully seeded CRNG is extremely difficult, and so this can
1494 result in dmesg getting spammed for a surprisingly long
1495 time. This is really bad from a security perspective, and
1496 so architecture maintainers really need to do what they can
1497 to get the CRNG seeded sooner after the system is booted.
1498 However, since users cannot do anything actionable to
1499 address this, by default the kernel will issue only a single
1500 warning for the first use of unseeded randomness.
1502 Say Y here if you want to receive warnings for all uses of
1503 unseeded randomness. This will be of use primarily for
1504 those developers interested in improving the security of
1505 Linux kernels running on their architecture (or
1508 config DEBUG_KOBJECT
1509 bool "kobject debugging"
1510 depends on DEBUG_KERNEL
1512 If you say Y here, some extra kobject debugging messages will be sent
1515 config DEBUG_KOBJECT_RELEASE
1516 bool "kobject release debugging"
1517 depends on DEBUG_OBJECTS_TIMERS
1519 kobjects are reference counted objects. This means that their
1520 last reference count put is not predictable, and the kobject can
1521 live on past the point at which a driver decides to drop it's
1522 initial reference to the kobject gained on allocation. An
1523 example of this would be a struct device which has just been
1526 However, some buggy drivers assume that after such an operation,
1527 the memory backing the kobject can be immediately freed. This
1528 goes completely against the principles of a refcounted object.
1530 If you say Y here, the kernel will delay the release of kobjects
1531 on the last reference count to improve the visibility of this
1532 kind of kobject release bug.
1534 config HAVE_DEBUG_BUGVERBOSE
1537 menu "Debug kernel data structures"
1540 bool "Debug linked list manipulation"
1541 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1543 Enable this to turn on extended checks in the linked-list
1549 bool "Debug priority linked list manipulation"
1550 depends on DEBUG_KERNEL
1552 Enable this to turn on extended checks in the priority-ordered
1553 linked-list (plist) walking routines. This checks the entire
1554 list multiple times during each manipulation.
1559 bool "Debug SG table operations"
1560 depends on DEBUG_KERNEL
1562 Enable this to turn on checks on scatter-gather tables. This can
1563 help find problems with drivers that do not properly initialize
1568 config DEBUG_NOTIFIERS
1569 bool "Debug notifier call chains"
1570 depends on DEBUG_KERNEL
1572 Enable this to turn on sanity checking for notifier call chains.
1573 This is most useful for kernel developers to make sure that
1574 modules properly unregister themselves from notifier chains.
1575 This is a relatively cheap check but if you care about maximum
1578 config BUG_ON_DATA_CORRUPTION
1579 bool "Trigger a BUG when data corruption is detected"
1582 Select this option if the kernel should BUG when it encounters
1583 data corruption in kernel memory structures when they get checked
1590 config DEBUG_CREDENTIALS
1591 bool "Debug credential management"
1592 depends on DEBUG_KERNEL
1594 Enable this to turn on some debug checking for credential
1595 management. The additional code keeps track of the number of
1596 pointers from task_structs to any given cred struct, and checks to
1597 see that this number never exceeds the usage count of the cred
1600 Furthermore, if SELinux is enabled, this also checks that the
1601 security pointer in the cred struct is never seen to be invalid.
1605 source "kernel/rcu/Kconfig.debug"
1607 config DEBUG_WQ_FORCE_RR_CPU
1608 bool "Force round-robin CPU selection for unbound work items"
1609 depends on DEBUG_KERNEL
1612 Workqueue used to implicitly guarantee that work items queued
1613 without explicit CPU specified are put on the local CPU. This
1614 guarantee is no longer true and while local CPU is still
1615 preferred work items may be put on foreign CPUs. Kernel
1616 parameter "workqueue.debug_force_rr_cpu" is added to force
1617 round-robin CPU selection to flush out usages which depend on the
1618 now broken guarantee. This config option enables the debug
1619 feature by default. When enabled, memory and cache locality will
1622 config DEBUG_BLOCK_EXT_DEVT
1623 bool "Force extended block device numbers and spread them"
1624 depends on DEBUG_KERNEL
1628 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1629 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1630 YOU ARE DOING. Distros, please enable this and fix whatever
1633 Conventionally, block device numbers are allocated from
1634 predetermined contiguous area. However, extended block area
1635 may introduce non-contiguous block device numbers. This
1636 option forces most block device numbers to be allocated from
1637 the extended space and spreads them to discover kernel or
1638 userland code paths which assume predetermined contiguous
1639 device number allocation.
1641 Note that turning on this debug option shuffles all the
1642 device numbers for all IDE and SCSI devices including libata
1643 ones, so root partition specified using device number
1644 directly (via rdev or root=MAJ:MIN) won't work anymore.
1645 Textual device names (root=/dev/sdXn) will continue to work.
1647 Say N if you are unsure.
1649 config CPU_HOTPLUG_STATE_CONTROL
1650 bool "Enable CPU hotplug state control"
1651 depends on DEBUG_KERNEL
1652 depends on HOTPLUG_CPU
1655 Allows to write steps between "offline" and "online" to the CPUs
1656 sysfs target file so states can be stepped granular. This is a debug
1657 option for now as the hotplug machinery cannot be stopped and
1658 restarted at arbitrary points yet.
1660 Say N if your are unsure.
1663 bool "Latency measuring infrastructure"
1664 depends on DEBUG_KERNEL
1665 depends on STACKTRACE_SUPPORT
1667 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
1674 Enable this option if you want to use the LatencyTOP tool
1675 to find out which userspace is blocking on what kernel operations.
1677 source "kernel/trace/Kconfig"
1679 config PROVIDE_OHCI1394_DMA_INIT
1680 bool "Remote debugging over FireWire early on boot"
1681 depends on PCI && X86
1683 If you want to debug problems which hang or crash the kernel early
1684 on boot and the crashing machine has a FireWire port, you can use
1685 this feature to remotely access the memory of the crashed machine
1686 over FireWire. This employs remote DMA as part of the OHCI1394
1687 specification which is now the standard for FireWire controllers.
1689 With remote DMA, you can monitor the printk buffer remotely using
1690 firescope and access all memory below 4GB using fireproxy from gdb.
1691 Even controlling a kernel debugger is possible using remote DMA.
1695 If ohci1394_dma=early is used as boot parameter, it will initialize
1696 all OHCI1394 controllers which are found in the PCI config space.
1698 As all changes to the FireWire bus such as enabling and disabling
1699 devices cause a bus reset and thereby disable remote DMA for all
1700 devices, be sure to have the cable plugged and FireWire enabled on
1701 the debugging host before booting the debug target for debugging.
1703 This code (~1k) is freed after boot. By then, the firewire stack
1704 in charge of the OHCI-1394 controllers should be used instead.
1706 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1708 source "samples/Kconfig"
1710 config ARCH_HAS_DEVMEM_IS_ALLOWED
1713 config STRICT_DEVMEM
1714 bool "Filter access to /dev/mem"
1715 depends on MMU && DEVMEM
1716 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1717 default y if PPC || X86 || ARM64
1719 If this option is disabled, you allow userspace (root) access to all
1720 of memory, including kernel and userspace memory. Accidental
1721 access to this is obviously disastrous, but specific access can
1722 be used by people debugging the kernel. Note that with PAT support
1723 enabled, even in this case there are restrictions on /dev/mem
1724 use due to the cache aliasing requirements.
1726 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1727 file only allows userspace access to PCI space and the BIOS code and
1728 data regions. This is sufficient for dosemu and X and all common
1733 config IO_STRICT_DEVMEM
1734 bool "Filter I/O access to /dev/mem"
1735 depends on STRICT_DEVMEM
1737 If this option is disabled, you allow userspace (root) access to all
1738 io-memory regardless of whether a driver is actively using that
1739 range. Accidental access to this is obviously disastrous, but
1740 specific access can be used by people debugging kernel drivers.
1742 If this option is switched on, the /dev/mem file only allows
1743 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1744 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1745 if the driver using a given range cannot be disabled.
1749 menu "$(SRCARCH) Debugging"
1751 source "arch/$(SRCARCH)/Kconfig.debug"
1755 menu "Kernel Testing and Coverage"
1757 source "lib/kunit/Kconfig"
1759 config NOTIFIER_ERROR_INJECTION
1760 tristate "Notifier error injection"
1761 depends on DEBUG_KERNEL
1764 This option provides the ability to inject artificial errors to
1765 specified notifier chain callbacks. It is useful to test the error
1766 handling of notifier call chain failures.
1770 config PM_NOTIFIER_ERROR_INJECT
1771 tristate "PM notifier error injection module"
1772 depends on PM && NOTIFIER_ERROR_INJECTION
1773 default m if PM_DEBUG
1775 This option provides the ability to inject artificial errors to
1776 PM notifier chain callbacks. It is controlled through debugfs
1777 interface /sys/kernel/debug/notifier-error-inject/pm
1779 If the notifier call chain should be failed with some events
1780 notified, write the error code to "actions/<notifier event>/error".
1782 Example: Inject PM suspend error (-12 = -ENOMEM)
1784 # cd /sys/kernel/debug/notifier-error-inject/pm/
1785 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1786 # echo mem > /sys/power/state
1787 bash: echo: write error: Cannot allocate memory
1789 To compile this code as a module, choose M here: the module will
1790 be called pm-notifier-error-inject.
1794 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1795 tristate "OF reconfig notifier error injection module"
1796 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1798 This option provides the ability to inject artificial errors to
1799 OF reconfig notifier chain callbacks. It is controlled
1800 through debugfs interface under
1801 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1803 If the notifier call chain should be failed with some events
1804 notified, write the error code to "actions/<notifier event>/error".
1806 To compile this code as a module, choose M here: the module will
1807 be called of-reconfig-notifier-error-inject.
1811 config NETDEV_NOTIFIER_ERROR_INJECT
1812 tristate "Netdev notifier error injection module"
1813 depends on NET && NOTIFIER_ERROR_INJECTION
1815 This option provides the ability to inject artificial errors to
1816 netdevice notifier chain callbacks. It is controlled through debugfs
1817 interface /sys/kernel/debug/notifier-error-inject/netdev
1819 If the notifier call chain should be failed with some events
1820 notified, write the error code to "actions/<notifier event>/error".
1822 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1824 # cd /sys/kernel/debug/notifier-error-inject/netdev
1825 # echo -22 > actions/NETDEV_CHANGEMTU/error
1826 # ip link set eth0 mtu 1024
1827 RTNETLINK answers: Invalid argument
1829 To compile this code as a module, choose M here: the module will
1830 be called netdev-notifier-error-inject.
1834 config FUNCTION_ERROR_INJECTION
1836 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1838 config FAULT_INJECTION
1839 bool "Fault-injection framework"
1840 depends on DEBUG_KERNEL
1842 Provide fault-injection framework.
1843 For more details, see Documentation/fault-injection/.
1846 bool "Fault-injection capability for kmalloc"
1847 depends on FAULT_INJECTION
1848 depends on SLAB || SLUB
1850 Provide fault-injection capability for kmalloc.
1852 config FAIL_PAGE_ALLOC
1853 bool "Fault-injection capability for alloc_pages()"
1854 depends on FAULT_INJECTION
1856 Provide fault-injection capability for alloc_pages().
1858 config FAULT_INJECTION_USERCOPY
1859 bool "Fault injection capability for usercopy functions"
1860 depends on FAULT_INJECTION
1862 Provides fault-injection capability to inject failures
1863 in usercopy functions (copy_from_user(), get_user(), ...).
1865 config FAIL_MAKE_REQUEST
1866 bool "Fault-injection capability for disk IO"
1867 depends on FAULT_INJECTION && BLOCK
1869 Provide fault-injection capability for disk IO.
1871 config FAIL_IO_TIMEOUT
1872 bool "Fault-injection capability for faking disk interrupts"
1873 depends on FAULT_INJECTION && BLOCK
1875 Provide fault-injection capability on end IO handling. This
1876 will make the block layer "forget" an interrupt as configured,
1877 thus exercising the error handling.
1879 Only works with drivers that use the generic timeout handling,
1880 for others it wont do anything.
1883 bool "Fault-injection capability for futexes"
1885 depends on FAULT_INJECTION && FUTEX
1887 Provide fault-injection capability for futexes.
1889 config FAULT_INJECTION_DEBUG_FS
1890 bool "Debugfs entries for fault-injection capabilities"
1891 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1893 Enable configuration of fault-injection capabilities via debugfs.
1895 config FAIL_FUNCTION
1896 bool "Fault-injection capability for functions"
1897 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1899 Provide function-based fault-injection capability.
1900 This will allow you to override a specific function with a return
1901 with given return value. As a result, function caller will see
1902 an error value and have to handle it. This is useful to test the
1903 error handling in various subsystems.
1905 config FAIL_MMC_REQUEST
1906 bool "Fault-injection capability for MMC IO"
1907 depends on FAULT_INJECTION_DEBUG_FS && MMC
1909 Provide fault-injection capability for MMC IO.
1910 This will make the mmc core return data errors. This is
1911 useful to test the error handling in the mmc block device
1912 and to test how the mmc host driver handles retries from
1915 config FAULT_INJECTION_STACKTRACE_FILTER
1916 bool "stacktrace filter for fault-injection capabilities"
1917 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1920 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
1922 Provide stacktrace filter for fault-injection capabilities
1924 config ARCH_HAS_KCOV
1927 An architecture should select this when it can successfully
1928 build and run with CONFIG_KCOV. This typically requires
1929 disabling instrumentation for some early boot code.
1931 config CC_HAS_SANCOV_TRACE_PC
1932 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1936 bool "Code coverage for fuzzing"
1937 depends on ARCH_HAS_KCOV
1938 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1940 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1942 KCOV exposes kernel code coverage information in a form suitable
1943 for coverage-guided fuzzing (randomized testing).
1945 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1946 different machines and across reboots. If you need stable PC values,
1947 disable RANDOMIZE_BASE.
1949 For more details, see Documentation/dev-tools/kcov.rst.
1951 config KCOV_ENABLE_COMPARISONS
1952 bool "Enable comparison operands collection by KCOV"
1954 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
1956 KCOV also exposes operands of every comparison in the instrumented
1957 code along with operand sizes and PCs of the comparison instructions.
1958 These operands can be used by fuzzing engines to improve the quality
1959 of fuzzing coverage.
1961 config KCOV_INSTRUMENT_ALL
1962 bool "Instrument all code by default"
1966 If you are doing generic system call fuzzing (like e.g. syzkaller),
1967 then you will want to instrument the whole kernel and you should
1968 say y here. If you are doing more targeted fuzzing (like e.g.
1969 filesystem fuzzing with AFL) then you will want to enable coverage
1970 for more specific subsets of files, and should say n here.
1972 config KCOV_IRQ_AREA_SIZE
1973 hex "Size of interrupt coverage collection area in words"
1977 KCOV uses preallocated per-cpu areas to collect coverage from
1978 soft interrupts. This specifies the size of those areas in the
1979 number of unsigned long words.
1981 menuconfig RUNTIME_TESTING_MENU
1982 bool "Runtime Testing"
1985 if RUNTIME_TESTING_MENU
1988 tristate "Linux Kernel Dump Test Tool Module"
1991 This module enables testing of the different dumping mechanisms by
1992 inducing system failures at predefined crash points.
1993 If you don't need it: say N
1994 Choose M here to compile this code as a module. The module will be
1997 Documentation on how to use the module can be found in
1998 Documentation/fault-injection/provoke-crashes.rst
2000 config TEST_LIST_SORT
2001 tristate "Linked list sorting test"
2002 depends on DEBUG_KERNEL || m
2004 Enable this to turn on 'list_sort()' function test. This test is
2005 executed only once during system boot (so affects only boot time),
2006 or at module load time.
2010 config TEST_MIN_HEAP
2011 tristate "Min heap test"
2012 depends on DEBUG_KERNEL || m
2014 Enable this to turn on min heap function tests. This test is
2015 executed only once during system boot (so affects only boot time),
2016 or at module load time.
2021 tristate "Array-based sort test"
2022 depends on DEBUG_KERNEL || m
2024 This option enables the self-test function of 'sort()' at boot,
2025 or at module load time.
2029 config KPROBES_SANITY_TEST
2030 bool "Kprobes sanity tests"
2031 depends on DEBUG_KERNEL
2034 This option provides for testing basic kprobes functionality on
2035 boot. Samples of kprobe and kretprobe are inserted and
2036 verified for functionality.
2038 Say N if you are unsure.
2040 config BACKTRACE_SELF_TEST
2041 tristate "Self test for the backtrace code"
2042 depends on DEBUG_KERNEL
2044 This option provides a kernel module that can be used to test
2045 the kernel stack backtrace code. This option is not useful
2046 for distributions or general kernels, but only for kernel
2047 developers working on architecture code.
2049 Note that if you want to also test saved backtraces, you will
2050 have to enable STACKTRACE as well.
2052 Say N if you are unsure.
2055 tristate "Red-Black tree test"
2056 depends on DEBUG_KERNEL
2058 A benchmark measuring the performance of the rbtree library.
2059 Also includes rbtree invariant checks.
2061 config REED_SOLOMON_TEST
2062 tristate "Reed-Solomon library test"
2063 depends on DEBUG_KERNEL || m
2065 select REED_SOLOMON_ENC16
2066 select REED_SOLOMON_DEC16
2068 This option enables the self-test function of rslib at boot,
2069 or at module load time.
2073 config INTERVAL_TREE_TEST
2074 tristate "Interval tree test"
2075 depends on DEBUG_KERNEL
2076 select INTERVAL_TREE
2078 A benchmark measuring the performance of the interval tree library
2081 tristate "Per cpu operations test"
2082 depends on m && DEBUG_KERNEL
2084 Enable this option to build test module which validates per-cpu
2089 config ATOMIC64_SELFTEST
2090 tristate "Perform an atomic64_t self-test"
2092 Enable this option to test the atomic64_t functions at boot or
2093 at module load time.
2097 config ASYNC_RAID6_TEST
2098 tristate "Self test for hardware accelerated raid6 recovery"
2099 depends on ASYNC_RAID6_RECOV
2102 This is a one-shot self test that permutes through the
2103 recovery of all the possible two disk failure scenarios for a
2104 N-disk array. Recovery is performed with the asynchronous
2105 raid6 recovery routines, and will optionally use an offload
2106 engine if one is available.
2111 tristate "Test functions located in the hexdump module at runtime"
2113 config TEST_STRING_HELPERS
2114 tristate "Test functions located in the string_helpers module at runtime"
2117 tristate "Test strscpy*() family of functions at runtime"
2120 tristate "Test kstrto*() family of functions at runtime"
2123 tristate "Test printf() family of functions at runtime"
2126 tristate "Test bitmap_*() family of functions at runtime"
2128 Enable this option to test the bitmap functions at boot.
2133 tristate "Test functions located in the uuid module at runtime"
2136 tristate "Test the XArray code at runtime"
2138 config TEST_OVERFLOW
2139 tristate "Test check_*_overflow() functions at runtime"
2141 config TEST_RHASHTABLE
2142 tristate "Perform selftest on resizable hash table"
2144 Enable this option to test the rhashtable functions at boot.
2149 tristate "Perform selftest on hash functions"
2151 Enable this option to test the kernel's integer (<linux/hash.h>),
2152 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
2153 hash functions on boot (or module load).
2155 This is intended to help people writing architecture-specific
2156 optimized versions. If unsure, say N.
2159 tristate "Perform selftest on IDA functions"
2162 tristate "Perform selftest on priority array manager"
2165 Enable this option to test priority array manager on boot
2170 config TEST_IRQ_TIMINGS
2171 bool "IRQ timings selftest"
2172 depends on IRQ_TIMINGS
2174 Enable this option to test the irq timings code on boot.
2179 tristate "Test module loading with 'hello world' module"
2182 This builds the "test_module" module that emits "Hello, world"
2183 on printk when loaded. It is designed to be used for basic
2184 evaluation of the module loading subsystem (for example when
2185 validating module verification). It lacks any extra dependencies,
2186 and will not normally be loaded by the system unless explicitly
2192 tristate "Test module for compilation of bitops operations"
2195 This builds the "test_bitops" module that is much like the
2196 TEST_LKM module except that it does a basic exercise of the
2197 set/clear_bit macros and get_count_order/long to make sure there are
2198 no compiler warnings from C=1 sparse checker or -Wextra
2199 compilations. It has no dependencies and doesn't run or load unless
2200 explicitly requested by name. for example: modprobe test_bitops.
2205 tristate "Test module for stress/performance analysis of vmalloc allocator"
2210 This builds the "test_vmalloc" module that should be used for
2211 stress and performance analysis. So, any new change for vmalloc
2212 subsystem can be evaluated from performance and stability point
2217 config TEST_USER_COPY
2218 tristate "Test user/kernel boundary protections"
2221 This builds the "test_user_copy" module that runs sanity checks
2222 on the copy_to/from_user infrastructure, making sure basic
2223 user/kernel boundary testing is working. If it fails to load,
2224 a regression has been detected in the user/kernel memory boundary
2230 tristate "Test BPF filter functionality"
2233 This builds the "test_bpf" module that runs various test vectors
2234 against the BPF interpreter or BPF JIT compiler depending on the
2235 current setting. This is in particular useful for BPF JIT compiler
2236 development, but also to run regression tests against changes in
2237 the interpreter code. It also enables test stubs for eBPF maps and
2238 verifier used by user space verifier testsuite.
2242 config TEST_BLACKHOLE_DEV
2243 tristate "Test blackhole netdev functionality"
2246 This builds the "test_blackhole_dev" module that validates the
2247 data path through this blackhole netdev.
2251 config FIND_BIT_BENCHMARK
2252 tristate "Test find_bit functions"
2254 This builds the "test_find_bit" module that measure find_*_bit()
2255 functions performance.
2259 config TEST_FIRMWARE
2260 tristate "Test firmware loading via userspace interface"
2261 depends on FW_LOADER
2263 This builds the "test_firmware" module that creates a userspace
2264 interface for testing firmware loading. This can be used to
2265 control the triggering of firmware loading without needing an
2266 actual firmware-using device. The contents can be rechecked by
2272 tristate "sysctl test driver"
2273 depends on PROC_SYSCTL
2275 This builds the "test_sysctl" module. This driver enables to test the
2276 proc sysctl interfaces available to drivers safely without affecting
2277 production knobs which might alter system functionality.
2281 config BITFIELD_KUNIT
2282 tristate "KUnit test bitfield functions at runtime"
2285 Enable this option to test the bitfield functions at boot.
2287 KUnit tests run during boot and output the results to the debug log
2288 in TAP format (http://testanything.org/). Only useful for kernel devs
2289 running the KUnit test harness, and not intended for inclusion into a
2292 For more information on KUnit and unit tests in general please refer
2293 to the KUnit documentation in Documentation/dev-tools/kunit/.
2297 config RESOURCE_KUNIT_TEST
2298 tristate "KUnit test for resource API"
2301 This builds the resource API unit test.
2302 Tests the logic of API provided by resource.c and ioport.h.
2303 For more information on KUnit and unit tests in general please refer
2304 to the KUnit documentation in Documentation/dev-tools/kunit/.
2308 config SYSCTL_KUNIT_TEST
2309 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2311 default KUNIT_ALL_TESTS
2313 This builds the proc sysctl unit test, which runs on boot.
2314 Tests the API contract and implementation correctness of sysctl.
2315 For more information on KUnit and unit tests in general please refer
2316 to the KUnit documentation in Documentation/dev-tools/kunit/.
2320 config LIST_KUNIT_TEST
2321 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2323 default KUNIT_ALL_TESTS
2325 This builds the linked list KUnit test suite.
2326 It tests that the API and basic functionality of the list_head type
2327 and associated macros.
2329 KUnit tests run during boot and output the results to the debug log
2330 in TAP format (https://testanything.org/). Only useful for kernel devs
2331 running the KUnit test harness, and not intended for inclusion into a
2334 For more information on KUnit and unit tests in general please refer
2335 to the KUnit documentation in Documentation/dev-tools/kunit/.
2339 config LINEAR_RANGES_TEST
2340 tristate "KUnit test for linear_ranges"
2342 select LINEAR_RANGES
2344 This builds the linear_ranges unit test, which runs on boot.
2345 Tests the linear_ranges logic correctness.
2346 For more information on KUnit and unit tests in general please refer
2347 to the KUnit documentation in Documentation/dev-tools/kunit/.
2351 config CMDLINE_KUNIT_TEST
2352 tristate "KUnit test for cmdline API"
2355 This builds the cmdline API unit test.
2356 Tests the logic of API provided by cmdline.c.
2357 For more information on KUnit and unit tests in general please refer
2358 to the KUnit documentation in Documentation/dev-tools/kunit/.
2363 tristate "KUnit test for bits.h"
2366 This builds the bits unit test.
2367 Tests the logic of macros defined in bits.h.
2368 For more information on KUnit and unit tests in general please refer
2369 to the KUnit documentation in Documentation/dev-tools/kunit/.
2374 tristate "udelay test driver"
2376 This builds the "udelay_test" module that helps to make sure
2377 that udelay() is working properly.
2381 config TEST_STATIC_KEYS
2382 tristate "Test static keys"
2385 Test the static key interfaces.
2390 tristate "kmod stress tester"
2392 depends on NETDEVICES && NET_CORE && INET # for TUN
2399 Test the kernel's module loading mechanism: kmod. kmod implements
2400 support to load modules using the Linux kernel's usermode helper.
2401 This test provides a series of tests against kmod.
2403 Although technically you can either build test_kmod as a module or
2404 into the kernel we disallow building it into the kernel since
2405 it stress tests request_module() and this will very likely cause
2406 some issues by taking over precious threads available from other
2407 module load requests, ultimately this could be fatal.
2411 tools/testing/selftests/kmod/kmod.sh --help
2415 config TEST_DEBUG_VIRTUAL
2416 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2417 depends on DEBUG_VIRTUAL
2419 Test the kernel's ability to detect incorrect calls to
2420 virt_to_phys() done against the non-linear part of the
2421 kernel's virtual address map.
2425 config TEST_MEMCAT_P
2426 tristate "Test memcat_p() helper function"
2428 Test the memcat_p() helper for correctly merging two
2429 pointer arrays together.
2433 config TEST_LIVEPATCH
2434 tristate "Test livepatching"
2436 depends on DYNAMIC_DEBUG
2437 depends on LIVEPATCH
2440 Test kernel livepatching features for correctness. The tests will
2441 load test modules that will be livepatched in various scenarios.
2443 To run all the livepatching tests:
2445 make -C tools/testing/selftests TARGETS=livepatch run_tests
2447 Alternatively, individual tests may be invoked:
2449 tools/testing/selftests/livepatch/test-callbacks.sh
2450 tools/testing/selftests/livepatch/test-livepatch.sh
2451 tools/testing/selftests/livepatch/test-shadow-vars.sh
2456 tristate "Perform selftest on object aggreration manager"
2460 Enable this option to test object aggregation manager on boot
2464 config TEST_STACKINIT
2465 tristate "Test level of stack variable initialization"
2467 Test if the kernel is zero-initializing stack variables and
2468 padding. Coverage is controlled by compiler flags,
2469 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2470 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2475 tristate "Test heap/page initialization"
2477 Test if the kernel is zero-initializing heap and page allocations.
2478 This can be useful to test init_on_alloc and init_on_free features.
2483 tristate "Test HMM (Heterogeneous Memory Management)"
2484 depends on TRANSPARENT_HUGEPAGE
2485 depends on DEVICE_PRIVATE
2489 This is a pseudo device driver solely for testing HMM.
2490 Say M here if you want to build the HMM test module.
2491 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2495 config TEST_FREE_PAGES
2496 tristate "Test freeing pages"
2498 Test that a memory leak does not occur due to a race between
2499 freeing a block of pages and a speculative page reference.
2500 Loading this module is safe if your kernel has the bug fixed.
2501 If the bug is not fixed, it will leak gigabytes of memory and
2502 probably OOM your system.
2505 tristate "Test floating point operations in kernel space"
2506 depends on X86 && !KCOV_INSTRUMENT_ALL
2508 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2509 which will trigger a sequence of floating point operations. This is used
2510 for self-testing floating point control register setting in
2515 endif # RUNTIME_TESTING_MENU
2520 This option adds a kernel parameter 'memtest', which allows memtest
2522 memtest=0, mean disabled; -- default
2523 memtest=1, mean do 1 test pattern;
2525 memtest=17, mean do 17 test patterns.
2526 If you are unsure how to answer this question, answer N.
2530 config HYPERV_TESTING
2531 bool "Microsoft Hyper-V driver testing"
2533 depends on HYPERV && DEBUG_FS
2535 Select this option to enable Hyper-V vmbus testing.
2537 endmenu # "Kernel Testing and Coverage"
2539 source "Documentation/Kconfig"
2541 endmenu # Kernel hacking
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