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.
215 config DEBUG_INFO_REDUCED
216 bool "Reduce debugging information"
217 depends on DEBUG_INFO
219 If you say Y here gcc is instructed to generate less debugging
220 information for structure types. This means that tools that
221 need full debugging information (like kgdb or systemtap) won't
222 be happy. But if you merely need debugging information to
223 resolve line numbers there is no loss. Advantage is that
224 build directory object sizes shrink dramatically over a full
225 DEBUG_INFO build and compile times are reduced too.
226 Only works with newer gcc versions.
228 config DEBUG_INFO_COMPRESSED
229 bool "Compressed debugging information"
230 depends on DEBUG_INFO
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 DEBUG_INFO
247 depends on $(cc-option,-gsplit-dwarf)
249 Generate debug info into separate .dwo files. This significantly
250 reduces the build directory size for builds with DEBUG_INFO,
251 because it stores the information only once on disk in .dwo
252 files instead of multiple times in object files and executables.
253 In addition the debug information is also compressed.
255 Requires recent gcc (4.7+) and recent gdb/binutils.
256 Any tool that packages or reads debug information would need
257 to know about the .dwo files and include them.
258 Incompatible with older versions of ccache.
260 config DEBUG_INFO_DWARF4
261 bool "Generate dwarf4 debuginfo"
262 depends on DEBUG_INFO
263 depends on $(cc-option,-gdwarf-4)
265 Generate dwarf4 debug info. This requires recent versions
266 of gcc and gdb. It makes the debug information larger.
267 But it significantly improves the success of resolving
268 variables in gdb on optimized code.
270 config DEBUG_INFO_BTF
271 bool "Generate BTF typeinfo"
272 depends on DEBUG_INFO
273 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
274 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
276 Generate deduplicated BTF type information from DWARF debug info.
277 Turning this on expects presence of pahole tool, which will convert
278 DWARF type info into equivalent deduplicated BTF type info.
281 bool "Provide GDB scripts for kernel debugging"
282 depends on DEBUG_INFO
284 This creates the required links to GDB helper scripts in the
285 build directory. If you load vmlinux into gdb, the helper
286 scripts will be automatically imported by gdb as well, and
287 additional functions are available to analyze a Linux kernel
288 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
291 config ENABLE_MUST_CHECK
292 bool "Enable __must_check logic"
295 Enable the __must_check logic in the kernel build. Disable this to
296 suppress the "warning: ignoring return value of 'foo', declared with
297 attribute warn_unused_result" messages.
300 int "Warn for stack frames larger than"
302 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
303 default 1280 if (!64BIT && PARISC)
304 default 1024 if (!64BIT && !PARISC)
305 default 2048 if 64BIT
307 Tell gcc to warn at build time for stack frames larger than this.
308 Setting this too low will cause a lot of warnings.
309 Setting it to 0 disables the warning.
311 config STRIP_ASM_SYMS
312 bool "Strip assembler-generated symbols during link"
315 Strip internal assembler-generated symbols during a link (symbols
316 that look like '.Lxxx') so they don't pollute the output of
317 get_wchan() and suchlike.
320 bool "Generate readable assembler code"
321 depends on DEBUG_KERNEL
323 Disable some compiler optimizations that tend to generate human unreadable
324 assembler output. This may make the kernel slightly slower, but it helps
325 to keep kernel developers who have to stare a lot at assembler listings
328 config HEADERS_INSTALL
329 bool "Install uapi headers to usr/include"
332 This option will install uapi headers (headers exported to user-space)
333 into the usr/include directory for use during the kernel build.
334 This is unneeded for building the kernel itself, but needed for some
335 user-space program samples. It is also needed by some features such
336 as uapi header sanity checks.
338 config DEBUG_SECTION_MISMATCH
339 bool "Enable full Section mismatch analysis"
341 The section mismatch analysis checks if there are illegal
342 references from one section to another section.
343 During linktime or runtime, some sections are dropped;
344 any use of code/data previously in these sections would
345 most likely result in an oops.
346 In the code, functions and variables are annotated with
347 __init,, etc. (see the full list in include/linux/init.h),
348 which results in the code/data being placed in specific sections.
349 The section mismatch analysis is always performed after a full
350 kernel build, and enabling this option causes the following
351 additional step to occur:
352 - Add the option -fno-inline-functions-called-once to gcc commands.
353 When inlining a function annotated with __init in a non-init
354 function, we would lose the section information and thus
355 the analysis would not catch the illegal reference.
356 This option tells gcc to inline less (but it does result in
359 config SECTION_MISMATCH_WARN_ONLY
360 bool "Make section mismatch errors non-fatal"
363 If you say N here, the build process will fail if there are any
364 section mismatch, instead of just throwing warnings.
369 # Select this config option from the architecture Kconfig, if it
370 # is preferred to always offer frame pointers as a config
371 # option on the architecture (regardless of KERNEL_DEBUG):
373 config ARCH_WANT_FRAME_POINTERS
377 bool "Compile the kernel with frame pointers"
378 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
379 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
381 If you say Y here the resulting kernel image will be slightly
382 larger and slower, but it gives very useful debugging information
383 in case of kernel bugs. (precise oopses/stacktraces/warnings)
385 config STACK_VALIDATION
386 bool "Compile-time stack metadata validation"
387 depends on HAVE_STACK_VALIDATION
390 Add compile-time checks to validate stack metadata, including frame
391 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
392 that runtime stack traces are more reliable.
394 This is also a prerequisite for generation of ORC unwind data, which
395 is needed for CONFIG_UNWINDER_ORC.
397 For more information, see
398 tools/objtool/Documentation/stack-validation.txt.
400 config VMLINUX_VALIDATION
402 depends on STACK_VALIDATION && DEBUG_ENTRY && !PARAVIRT
405 config DEBUG_FORCE_WEAK_PER_CPU
406 bool "Force weak per-cpu definitions"
407 depends on DEBUG_KERNEL
409 s390 and alpha require percpu variables in modules to be
410 defined weak to work around addressing range issue which
411 puts the following two restrictions on percpu variable
414 1. percpu symbols must be unique whether static or not
415 2. percpu variables can't be defined inside a function
417 To ensure that generic code follows the above rules, this
418 option forces all percpu variables to be defined as weak.
420 endmenu # "Compiler options"
422 menu "Generic Kernel Debugging Instruments"
425 bool "Magic SysRq key"
428 If you say Y here, you will have some control over the system even
429 if the system crashes for example during kernel debugging (e.g., you
430 will be able to flush the buffer cache to disk, reboot the system
431 immediately or dump some status information). This is accomplished
432 by pressing various keys while holding SysRq (Alt+PrintScreen). It
433 also works on a serial console (on PC hardware at least), if you
434 send a BREAK and then within 5 seconds a command keypress. The
435 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
436 Don't say Y unless you really know what this hack does.
438 config MAGIC_SYSRQ_DEFAULT_ENABLE
439 hex "Enable magic SysRq key functions by default"
440 depends on MAGIC_SYSRQ
443 Specifies which SysRq key functions are enabled by default.
444 This may be set to 1 or 0 to enable or disable them all, or
445 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
447 config MAGIC_SYSRQ_SERIAL
448 bool "Enable magic SysRq key over serial"
449 depends on MAGIC_SYSRQ
452 Many embedded boards have a disconnected TTL level serial which can
453 generate some garbage that can lead to spurious false sysrq detects.
454 This option allows you to decide whether you want to enable the
457 config MAGIC_SYSRQ_SERIAL_SEQUENCE
458 string "Char sequence that enables magic SysRq over serial"
459 depends on MAGIC_SYSRQ_SERIAL
462 Specifies a sequence of characters that can follow BREAK to enable
463 SysRq on a serial console.
465 If unsure, leave an empty string and the option will not be enabled.
468 bool "Debug Filesystem"
470 debugfs is a virtual file system that kernel developers use to put
471 debugging files into. Enable this option to be able to read and
472 write to these files.
474 For detailed documentation on the debugfs API, see
475 Documentation/filesystems/.
479 source "lib/Kconfig.kgdb"
481 source "lib/Kconfig.ubsan"
486 bool "Kernel debugging"
488 Say Y here if you are developing drivers or trying to debug and
489 identify kernel problems.
492 bool "Miscellaneous debug code"
494 depends on DEBUG_KERNEL
496 Say Y here if you need to enable miscellaneous debug code that should
497 be under a more specific debug option but isn't.
500 menu "Memory Debugging"
502 source "mm/Kconfig.debug"
505 bool "Debug object operations"
506 depends on DEBUG_KERNEL
508 If you say Y here, additional code will be inserted into the
509 kernel to track the life time of various objects and validate
510 the operations on those objects.
512 config DEBUG_OBJECTS_SELFTEST
513 bool "Debug objects selftest"
514 depends on DEBUG_OBJECTS
516 This enables the selftest of the object debug code.
518 config DEBUG_OBJECTS_FREE
519 bool "Debug objects in freed memory"
520 depends on DEBUG_OBJECTS
522 This enables checks whether a k/v free operation frees an area
523 which contains an object which has not been deactivated
524 properly. This can make kmalloc/kfree-intensive workloads
527 config DEBUG_OBJECTS_TIMERS
528 bool "Debug timer objects"
529 depends on DEBUG_OBJECTS
531 If you say Y here, additional code will be inserted into the
532 timer routines to track the life time of timer objects and
533 validate the timer operations.
535 config DEBUG_OBJECTS_WORK
536 bool "Debug work objects"
537 depends on DEBUG_OBJECTS
539 If you say Y here, additional code will be inserted into the
540 work queue routines to track the life time of work objects and
541 validate the work operations.
543 config DEBUG_OBJECTS_RCU_HEAD
544 bool "Debug RCU callbacks objects"
545 depends on DEBUG_OBJECTS
547 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
549 config DEBUG_OBJECTS_PERCPU_COUNTER
550 bool "Debug percpu counter objects"
551 depends on DEBUG_OBJECTS
553 If you say Y here, additional code will be inserted into the
554 percpu counter routines to track the life time of percpu counter
555 objects and validate the percpu counter operations.
557 config DEBUG_OBJECTS_ENABLE_DEFAULT
558 int "debug_objects bootup default value (0-1)"
561 depends on DEBUG_OBJECTS
563 Debug objects boot parameter default value
566 bool "Debug slab memory allocations"
567 depends on DEBUG_KERNEL && SLAB
569 Say Y here to have the kernel do limited verification on memory
570 allocation as well as poisoning memory on free to catch use of freed
571 memory. This can make kmalloc/kfree-intensive workloads much slower.
574 bool "SLUB debugging on by default"
575 depends on SLUB && SLUB_DEBUG
578 Boot with debugging on by default. SLUB boots by default with
579 the runtime debug capabilities switched off. Enabling this is
580 equivalent to specifying the "slub_debug" parameter on boot.
581 There is no support for more fine grained debug control like
582 possible with slub_debug=xxx. SLUB debugging may be switched
583 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
588 bool "Enable SLUB performance statistics"
589 depends on SLUB && SYSFS
591 SLUB statistics are useful to debug SLUBs allocation behavior in
592 order find ways to optimize the allocator. This should never be
593 enabled for production use since keeping statistics slows down
594 the allocator by a few percentage points. The slabinfo command
595 supports the determination of the most active slabs to figure
596 out which slabs are relevant to a particular load.
597 Try running: slabinfo -DA
599 config HAVE_DEBUG_KMEMLEAK
602 config DEBUG_KMEMLEAK
603 bool "Kernel memory leak detector"
604 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
606 select STACKTRACE if STACKTRACE_SUPPORT
610 Say Y here if you want to enable the memory leak
611 detector. The memory allocation/freeing is traced in a way
612 similar to the Boehm's conservative garbage collector, the
613 difference being that the orphan objects are not freed but
614 only shown in /sys/kernel/debug/kmemleak. Enabling this
615 feature will introduce an overhead to memory
616 allocations. See Documentation/dev-tools/kmemleak.rst for more
619 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
620 of finding leaks due to the slab objects poisoning.
622 In order to access the kmemleak file, debugfs needs to be
623 mounted (usually at /sys/kernel/debug).
625 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
626 int "Kmemleak memory pool size"
627 depends on DEBUG_KMEMLEAK
631 Kmemleak must track all the memory allocations to avoid
632 reporting false positives. Since memory may be allocated or
633 freed before kmemleak is fully initialised, use a static pool
634 of metadata objects to track such callbacks. After kmemleak is
635 fully initialised, this memory pool acts as an emergency one
636 if slab allocations fail.
638 config DEBUG_KMEMLEAK_TEST
639 tristate "Simple test for the kernel memory leak detector"
640 depends on DEBUG_KMEMLEAK && m
642 This option enables a module that explicitly leaks memory.
646 config DEBUG_KMEMLEAK_DEFAULT_OFF
647 bool "Default kmemleak to off"
648 depends on DEBUG_KMEMLEAK
650 Say Y here to disable kmemleak by default. It can then be enabled
651 on the command line via kmemleak=on.
653 config DEBUG_KMEMLEAK_AUTO_SCAN
654 bool "Enable kmemleak auto scan thread on boot up"
656 depends on DEBUG_KMEMLEAK
658 Depending on the cpu, kmemleak scan may be cpu intensive and can
659 stall user tasks at times. This option enables/disables automatic
660 kmemleak scan at boot up.
662 Say N here to disable kmemleak auto scan thread to stop automatic
663 scanning. Disabling this option disables automatic reporting of
668 config DEBUG_STACK_USAGE
669 bool "Stack utilization instrumentation"
670 depends on DEBUG_KERNEL && !IA64
672 Enables the display of the minimum amount of free stack which each
673 task has ever had available in the sysrq-T and sysrq-P debug output.
675 This option will slow down process creation somewhat.
677 config SCHED_STACK_END_CHECK
678 bool "Detect stack corruption on calls to schedule()"
679 depends on DEBUG_KERNEL
682 This option checks for a stack overrun on calls to schedule().
683 If the stack end location is found to be over written always panic as
684 the content of the corrupted region can no longer be trusted.
685 This is to ensure no erroneous behaviour occurs which could result in
686 data corruption or a sporadic crash at a later stage once the region
687 is examined. The runtime overhead introduced is minimal.
689 config ARCH_HAS_DEBUG_VM_PGTABLE
692 An architecture should select this when it can successfully
693 build and run DEBUG_VM_PGTABLE.
697 depends on DEBUG_KERNEL
699 Enable this to turn on extended checks in the virtual-memory system
700 that may impact performance.
704 config DEBUG_VM_VMACACHE
705 bool "Debug VMA caching"
708 Enable this to turn on VMA caching debug information. Doing so
709 can cause significant overhead, so only enable it in non-production
715 bool "Debug VM red-black trees"
718 Enable VM red-black tree debugging information and extra validations.
722 config DEBUG_VM_PGFLAGS
723 bool "Debug page-flags operations"
726 Enables extra validation on page flags operations.
730 config DEBUG_VM_PGTABLE
731 bool "Debug arch page table for semantics compliance"
733 depends on ARCH_HAS_DEBUG_VM_PGTABLE
734 default y if DEBUG_VM
736 This option provides a debug method which can be used to test
737 architecture page table helper functions on various platforms in
738 verifying if they comply with expected generic MM semantics. This
739 will help architecture code in making sure that any changes or
740 new additions of these helpers still conform to expected
741 semantics of the generic MM. Platforms will have to opt in for
742 this through ARCH_HAS_DEBUG_VM_PGTABLE.
746 config ARCH_HAS_DEBUG_VIRTUAL
750 bool "Debug VM translations"
751 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
753 Enable some costly sanity checks in virtual to page code. This can
754 catch mistakes with virt_to_page() and friends.
758 config DEBUG_NOMMU_REGIONS
759 bool "Debug the global anon/private NOMMU mapping region tree"
760 depends on DEBUG_KERNEL && !MMU
762 This option causes the global tree of anonymous and private mapping
763 regions to be regularly checked for invalid topology.
765 config DEBUG_MEMORY_INIT
766 bool "Debug memory initialisation" if EXPERT
769 Enable this for additional checks during memory initialisation.
770 The sanity checks verify aspects of the VM such as the memory model
771 and other information provided by the architecture. Verbose
772 information will be printed at KERN_DEBUG loglevel depending
773 on the mminit_loglevel= command-line option.
777 config MEMORY_NOTIFIER_ERROR_INJECT
778 tristate "Memory hotplug notifier error injection module"
779 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
781 This option provides the ability to inject artificial errors to
782 memory hotplug notifier chain callbacks. It is controlled through
783 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
785 If the notifier call chain should be failed with some events
786 notified, write the error code to "actions/<notifier event>/error".
788 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
790 # cd /sys/kernel/debug/notifier-error-inject/memory
791 # echo -12 > actions/MEM_GOING_OFFLINE/error
792 # echo offline > /sys/devices/system/memory/memoryXXX/state
793 bash: echo: write error: Cannot allocate memory
795 To compile this code as a module, choose M here: the module will
796 be called memory-notifier-error-inject.
800 config DEBUG_PER_CPU_MAPS
801 bool "Debug access to per_cpu maps"
802 depends on DEBUG_KERNEL
805 Say Y to verify that the per_cpu map being accessed has
806 been set up. This adds a fair amount of code to kernel memory
807 and decreases performance.
812 bool "Highmem debugging"
813 depends on DEBUG_KERNEL && HIGHMEM
815 This option enables additional error checking for high memory
816 systems. Disable for production systems.
818 config HAVE_DEBUG_STACKOVERFLOW
821 config DEBUG_STACKOVERFLOW
822 bool "Check for stack overflows"
823 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
825 Say Y here if you want to check for overflows of kernel, IRQ
826 and exception stacks (if your architecture uses them). This
827 option will show detailed messages if free stack space drops
828 below a certain limit.
830 These kinds of bugs usually occur when call-chains in the
831 kernel get too deep, especially when interrupts are
834 Use this in cases where you see apparently random memory
835 corruption, especially if it appears in 'struct thread_info'
837 If in doubt, say "N".
839 source "lib/Kconfig.kasan"
841 endmenu # "Memory Debugging"
844 bool "Debug shared IRQ handlers"
845 depends on DEBUG_KERNEL
847 Enable this to generate a spurious interrupt as soon as a shared
848 interrupt handler is registered, and just before one is deregistered.
849 Drivers ought to be able to handle interrupts coming in at those
850 points; some don't and need to be caught.
852 menu "Debug Oops, Lockups and Hangs"
857 Say Y here to enable the kernel to panic when it oopses. This
858 has the same effect as setting oops=panic on the kernel command
861 This feature is useful to ensure that the kernel does not do
862 anything erroneous after an oops which could result in data
863 corruption or other issues.
867 config PANIC_ON_OOPS_VALUE
870 default 0 if !PANIC_ON_OOPS
871 default 1 if PANIC_ON_OOPS
877 Set the timeout value (in seconds) until a reboot occurs when the
878 the kernel panics. If n = 0, then we wait forever. A timeout
879 value n > 0 will wait n seconds before rebooting, while a timeout
880 value n < 0 will reboot immediately.
882 config LOCKUP_DETECTOR
885 config SOFTLOCKUP_DETECTOR
886 bool "Detect Soft Lockups"
887 depends on DEBUG_KERNEL && !S390
888 select LOCKUP_DETECTOR
890 Say Y here to enable the kernel to act as a watchdog to detect
893 Softlockups are bugs that cause the kernel to loop in kernel
894 mode for more than 20 seconds, without giving other tasks a
895 chance to run. The current stack trace is displayed upon
896 detection and the system will stay locked up.
898 config BOOTPARAM_SOFTLOCKUP_PANIC
899 bool "Panic (Reboot) On Soft Lockups"
900 depends on SOFTLOCKUP_DETECTOR
902 Say Y here to enable the kernel to panic on "soft lockups",
903 which are bugs that cause the kernel to loop in kernel
904 mode for more than 20 seconds (configurable using the watchdog_thresh
905 sysctl), without giving other tasks a chance to run.
907 The panic can be used in combination with panic_timeout,
908 to cause the system to reboot automatically after a
909 lockup has been detected. This feature is useful for
910 high-availability systems that have uptime guarantees and
911 where a lockup must be resolved ASAP.
915 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
917 depends on SOFTLOCKUP_DETECTOR
919 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
920 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
922 config HARDLOCKUP_DETECTOR_PERF
924 select SOFTLOCKUP_DETECTOR
927 # Enables a timestamp based low pass filter to compensate for perf based
928 # hard lockup detection which runs too fast due to turbo modes.
930 config HARDLOCKUP_CHECK_TIMESTAMP
934 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
935 # lockup detector rather than the perf based detector.
937 config HARDLOCKUP_DETECTOR
938 bool "Detect Hard Lockups"
939 depends on DEBUG_KERNEL && !S390
940 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
941 select LOCKUP_DETECTOR
942 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
943 select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH
945 Say Y here to enable the kernel to act as a watchdog to detect
948 Hardlockups are bugs that cause the CPU to loop in kernel mode
949 for more than 10 seconds, without letting other interrupts have a
950 chance to run. The current stack trace is displayed upon detection
951 and the system will stay locked up.
953 config BOOTPARAM_HARDLOCKUP_PANIC
954 bool "Panic (Reboot) On Hard Lockups"
955 depends on HARDLOCKUP_DETECTOR
957 Say Y here to enable the kernel to panic on "hard lockups",
958 which are bugs that cause the kernel to loop in kernel
959 mode with interrupts disabled for more than 10 seconds (configurable
960 using the watchdog_thresh sysctl).
964 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
966 depends on HARDLOCKUP_DETECTOR
968 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
969 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
971 config DETECT_HUNG_TASK
972 bool "Detect Hung Tasks"
973 depends on DEBUG_KERNEL
974 default SOFTLOCKUP_DETECTOR
976 Say Y here to enable the kernel to detect "hung tasks",
977 which are bugs that cause the task to be stuck in
978 uninterruptible "D" state indefinitely.
980 When a hung task is detected, the kernel will print the
981 current stack trace (which you should report), but the
982 task will stay in uninterruptible state. If lockdep is
983 enabled then all held locks will also be reported. This
984 feature has negligible overhead.
986 config DEFAULT_HUNG_TASK_TIMEOUT
987 int "Default timeout for hung task detection (in seconds)"
988 depends on DETECT_HUNG_TASK
991 This option controls the default timeout (in seconds) used
992 to determine when a task has become non-responsive and should
995 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
996 sysctl or by writing a value to
997 /proc/sys/kernel/hung_task_timeout_secs.
999 A timeout of 0 disables the check. The default is two minutes.
1000 Keeping the default should be fine in most cases.
1002 config BOOTPARAM_HUNG_TASK_PANIC
1003 bool "Panic (Reboot) On Hung Tasks"
1004 depends on DETECT_HUNG_TASK
1006 Say Y here to enable the kernel to panic on "hung tasks",
1007 which are bugs that cause the kernel to leave a task stuck
1008 in uninterruptible "D" state.
1010 The panic can be used in combination with panic_timeout,
1011 to cause the system to reboot automatically after a
1012 hung task has been detected. This feature is useful for
1013 high-availability systems that have uptime guarantees and
1014 where a hung tasks must be resolved ASAP.
1018 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
1020 depends on DETECT_HUNG_TASK
1022 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
1023 default 1 if BOOTPARAM_HUNG_TASK_PANIC
1026 bool "Detect Workqueue Stalls"
1027 depends on DEBUG_KERNEL
1029 Say Y here to enable stall detection on workqueues. If a
1030 worker pool doesn't make forward progress on a pending work
1031 item for over a given amount of time, 30s by default, a
1032 warning message is printed along with dump of workqueue
1033 state. This can be configured through kernel parameter
1034 "workqueue.watchdog_thresh" and its sysfs counterpart.
1037 tristate "Test module to generate lockups"
1039 This builds the "test_lockup" module that helps to make sure
1040 that watchdogs and lockup detectors are working properly.
1042 Depending on module parameters it could emulate soft or hard
1043 lockup, "hung task", or locking arbitrary lock for a long time.
1044 Also it could generate series of lockups with cooling-down periods.
1048 endmenu # "Debug lockups and hangs"
1050 menu "Scheduler Debugging"
1053 bool "Collect scheduler debugging info"
1054 depends on DEBUG_KERNEL && PROC_FS
1057 If you say Y here, the /proc/sched_debug file will be provided
1058 that can help debug the scheduler. The runtime overhead of this
1066 bool "Collect scheduler statistics"
1067 depends on DEBUG_KERNEL && PROC_FS
1070 If you say Y here, additional code will be inserted into the
1071 scheduler and related routines to collect statistics about
1072 scheduler behavior and provide them in /proc/schedstat. These
1073 stats may be useful for both tuning and debugging the scheduler
1074 If you aren't debugging the scheduler or trying to tune a specific
1075 application, you can say N to avoid the very slight overhead
1080 config DEBUG_TIMEKEEPING
1081 bool "Enable extra timekeeping sanity checking"
1083 This option will enable additional timekeeping sanity checks
1084 which may be helpful when diagnosing issues where timekeeping
1085 problems are suspected.
1087 This may include checks in the timekeeping hotpaths, so this
1088 option may have a (very small) performance impact to some
1093 config DEBUG_PREEMPT
1094 bool "Debug preemptible kernel"
1095 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1098 If you say Y here then the kernel will use a debug variant of the
1099 commonly used smp_processor_id() function and will print warnings
1100 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1101 will detect preemption count underflows.
1103 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1105 config LOCK_DEBUGGING_SUPPORT
1107 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1110 config PROVE_LOCKING
1111 bool "Lock debugging: prove locking correctness"
1112 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1114 select DEBUG_SPINLOCK
1115 select DEBUG_MUTEXES
1116 select DEBUG_RT_MUTEXES if RT_MUTEXES
1118 select DEBUG_WW_MUTEX_SLOWPATH
1119 select DEBUG_LOCK_ALLOC
1120 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1121 select TRACE_IRQFLAGS
1124 This feature enables the kernel to prove that all locking
1125 that occurs in the kernel runtime is mathematically
1126 correct: that under no circumstance could an arbitrary (and
1127 not yet triggered) combination of observed locking
1128 sequences (on an arbitrary number of CPUs, running an
1129 arbitrary number of tasks and interrupt contexts) cause a
1132 In short, this feature enables the kernel to report locking
1133 related deadlocks before they actually occur.
1135 The proof does not depend on how hard and complex a
1136 deadlock scenario would be to trigger: how many
1137 participant CPUs, tasks and irq-contexts would be needed
1138 for it to trigger. The proof also does not depend on
1139 timing: if a race and a resulting deadlock is possible
1140 theoretically (no matter how unlikely the race scenario
1141 is), it will be proven so and will immediately be
1142 reported by the kernel (once the event is observed that
1143 makes the deadlock theoretically possible).
1145 If a deadlock is impossible (i.e. the locking rules, as
1146 observed by the kernel, are mathematically correct), the
1147 kernel reports nothing.
1149 NOTE: this feature can also be enabled for rwlocks, mutexes
1150 and rwsems - in which case all dependencies between these
1151 different locking variants are observed and mapped too, and
1152 the proof of observed correctness is also maintained for an
1153 arbitrary combination of these separate locking variants.
1155 For more details, see Documentation/locking/lockdep-design.rst.
1157 config PROVE_RAW_LOCK_NESTING
1158 bool "Enable raw_spinlock - spinlock nesting checks"
1159 depends on PROVE_LOCKING
1162 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1163 that the lock nesting rules for PREEMPT_RT enabled kernels are
1166 NOTE: There are known nesting problems. So if you enable this
1167 option expect lockdep splats until these problems have been fully
1168 addressed which is work in progress. This config switch allows to
1169 identify and analyze these problems. It will be removed and the
1170 check permanentely enabled once the main issues have been fixed.
1172 If unsure, select N.
1175 bool "Lock usage statistics"
1176 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1178 select DEBUG_SPINLOCK
1179 select DEBUG_MUTEXES
1180 select DEBUG_RT_MUTEXES if RT_MUTEXES
1181 select DEBUG_LOCK_ALLOC
1184 This feature enables tracking lock contention points
1186 For more details, see Documentation/locking/lockstat.rst
1188 This also enables lock events required by "perf lock",
1190 If you want to use "perf lock", you also need to turn on
1191 CONFIG_EVENT_TRACING.
1193 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1194 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1196 config DEBUG_RT_MUTEXES
1197 bool "RT Mutex debugging, deadlock detection"
1198 depends on DEBUG_KERNEL && RT_MUTEXES
1200 This allows rt mutex semantics violations and rt mutex related
1201 deadlocks (lockups) to be detected and reported automatically.
1203 config DEBUG_SPINLOCK
1204 bool "Spinlock and rw-lock debugging: basic checks"
1205 depends on DEBUG_KERNEL
1206 select UNINLINE_SPIN_UNLOCK
1208 Say Y here and build SMP to catch missing spinlock initialization
1209 and certain other kinds of spinlock errors commonly made. This is
1210 best used in conjunction with the NMI watchdog so that spinlock
1211 deadlocks are also debuggable.
1213 config DEBUG_MUTEXES
1214 bool "Mutex debugging: basic checks"
1215 depends on DEBUG_KERNEL
1217 This feature allows mutex semantics violations to be detected and
1220 config DEBUG_WW_MUTEX_SLOWPATH
1221 bool "Wait/wound mutex debugging: Slowpath testing"
1222 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1223 select DEBUG_LOCK_ALLOC
1224 select DEBUG_SPINLOCK
1225 select DEBUG_MUTEXES
1227 This feature enables slowpath testing for w/w mutex users by
1228 injecting additional -EDEADLK wound/backoff cases. Together with
1229 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1230 will test all possible w/w mutex interface abuse with the
1231 exception of simply not acquiring all the required locks.
1232 Note that this feature can introduce significant overhead, so
1233 it really should not be enabled in a production or distro kernel,
1234 even a debug kernel. If you are a driver writer, enable it. If
1235 you are a distro, do not.
1238 bool "RW Semaphore debugging: basic checks"
1239 depends on DEBUG_KERNEL
1241 This debugging feature allows mismatched rw semaphore locks
1242 and unlocks to be detected and reported.
1244 config DEBUG_LOCK_ALLOC
1245 bool "Lock debugging: detect incorrect freeing of live locks"
1246 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1247 select DEBUG_SPINLOCK
1248 select DEBUG_MUTEXES
1249 select DEBUG_RT_MUTEXES if RT_MUTEXES
1252 This feature will check whether any held lock (spinlock, rwlock,
1253 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1254 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1255 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1256 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1257 held during task exit.
1261 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1263 select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86
1267 config LOCKDEP_SMALL
1270 config DEBUG_LOCKDEP
1271 bool "Lock dependency engine debugging"
1272 depends on DEBUG_KERNEL && LOCKDEP
1274 If you say Y here, the lock dependency engine will do
1275 additional runtime checks to debug itself, at the price
1276 of more runtime overhead.
1278 config DEBUG_ATOMIC_SLEEP
1279 bool "Sleep inside atomic section checking"
1280 select PREEMPT_COUNT
1281 depends on DEBUG_KERNEL
1282 depends on !ARCH_NO_PREEMPT
1284 If you say Y here, various routines which may sleep will become very
1285 noisy if they are called inside atomic sections: when a spinlock is
1286 held, inside an rcu read side critical section, inside preempt disabled
1287 sections, inside an interrupt, etc...
1289 config DEBUG_LOCKING_API_SELFTESTS
1290 bool "Locking API boot-time self-tests"
1291 depends on DEBUG_KERNEL
1293 Say Y here if you want the kernel to run a short self-test during
1294 bootup. The self-test checks whether common types of locking bugs
1295 are detected by debugging mechanisms or not. (if you disable
1296 lock debugging then those bugs wont be detected of course.)
1297 The following locking APIs are covered: spinlocks, rwlocks,
1300 config LOCK_TORTURE_TEST
1301 tristate "torture tests for locking"
1302 depends on DEBUG_KERNEL
1305 This option provides a kernel module that runs torture tests
1306 on kernel locking primitives. The kernel module may be built
1307 after the fact on the running kernel to be tested, if desired.
1309 Say Y here if you want kernel locking-primitive torture tests
1310 to be built into the kernel.
1311 Say M if you want these torture tests to build as a module.
1312 Say N if you are unsure.
1314 config WW_MUTEX_SELFTEST
1315 tristate "Wait/wound mutex selftests"
1317 This option provides a kernel module that runs tests on the
1318 on the struct ww_mutex locking API.
1320 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1321 with this test harness.
1323 Say M if you want these self tests to build as a module.
1324 Say N if you are unsure.
1326 endmenu # lock debugging
1328 config TRACE_IRQFLAGS
1329 depends on TRACE_IRQFLAGS_SUPPORT
1332 Enables hooks to interrupt enabling and disabling for
1333 either tracing or lock debugging.
1335 config TRACE_IRQFLAGS_NMI
1337 depends on TRACE_IRQFLAGS
1338 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1341 bool "Stack backtrace support"
1342 depends on STACKTRACE_SUPPORT
1344 This option causes the kernel to create a /proc/pid/stack for
1345 every process, showing its current stack trace.
1346 It is also used by various kernel debugging features that require
1347 stack trace generation.
1349 config WARN_ALL_UNSEEDED_RANDOM
1350 bool "Warn for all uses of unseeded randomness"
1353 Some parts of the kernel contain bugs relating to their use of
1354 cryptographically secure random numbers before it's actually possible
1355 to generate those numbers securely. This setting ensures that these
1356 flaws don't go unnoticed, by enabling a message, should this ever
1357 occur. This will allow people with obscure setups to know when things
1358 are going wrong, so that they might contact developers about fixing
1361 Unfortunately, on some models of some architectures getting
1362 a fully seeded CRNG is extremely difficult, and so this can
1363 result in dmesg getting spammed for a surprisingly long
1364 time. This is really bad from a security perspective, and
1365 so architecture maintainers really need to do what they can
1366 to get the CRNG seeded sooner after the system is booted.
1367 However, since users cannot do anything actionable to
1368 address this, by default the kernel will issue only a single
1369 warning for the first use of unseeded randomness.
1371 Say Y here if you want to receive warnings for all uses of
1372 unseeded randomness. This will be of use primarily for
1373 those developers interested in improving the security of
1374 Linux kernels running on their architecture (or
1377 config DEBUG_KOBJECT
1378 bool "kobject debugging"
1379 depends on DEBUG_KERNEL
1381 If you say Y here, some extra kobject debugging messages will be sent
1384 config DEBUG_KOBJECT_RELEASE
1385 bool "kobject release debugging"
1386 depends on DEBUG_OBJECTS_TIMERS
1388 kobjects are reference counted objects. This means that their
1389 last reference count put is not predictable, and the kobject can
1390 live on past the point at which a driver decides to drop it's
1391 initial reference to the kobject gained on allocation. An
1392 example of this would be a struct device which has just been
1395 However, some buggy drivers assume that after such an operation,
1396 the memory backing the kobject can be immediately freed. This
1397 goes completely against the principles of a refcounted object.
1399 If you say Y here, the kernel will delay the release of kobjects
1400 on the last reference count to improve the visibility of this
1401 kind of kobject release bug.
1403 config HAVE_DEBUG_BUGVERBOSE
1406 menu "Debug kernel data structures"
1409 bool "Debug linked list manipulation"
1410 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1412 Enable this to turn on extended checks in the linked-list
1418 bool "Debug priority linked list manipulation"
1419 depends on DEBUG_KERNEL
1421 Enable this to turn on extended checks in the priority-ordered
1422 linked-list (plist) walking routines. This checks the entire
1423 list multiple times during each manipulation.
1428 bool "Debug SG table operations"
1429 depends on DEBUG_KERNEL
1431 Enable this to turn on checks on scatter-gather tables. This can
1432 help find problems with drivers that do not properly initialize
1437 config DEBUG_NOTIFIERS
1438 bool "Debug notifier call chains"
1439 depends on DEBUG_KERNEL
1441 Enable this to turn on sanity checking for notifier call chains.
1442 This is most useful for kernel developers to make sure that
1443 modules properly unregister themselves from notifier chains.
1444 This is a relatively cheap check but if you care about maximum
1447 config BUG_ON_DATA_CORRUPTION
1448 bool "Trigger a BUG when data corruption is detected"
1451 Select this option if the kernel should BUG when it encounters
1452 data corruption in kernel memory structures when they get checked
1459 config DEBUG_CREDENTIALS
1460 bool "Debug credential management"
1461 depends on DEBUG_KERNEL
1463 Enable this to turn on some debug checking for credential
1464 management. The additional code keeps track of the number of
1465 pointers from task_structs to any given cred struct, and checks to
1466 see that this number never exceeds the usage count of the cred
1469 Furthermore, if SELinux is enabled, this also checks that the
1470 security pointer in the cred struct is never seen to be invalid.
1474 source "kernel/rcu/Kconfig.debug"
1476 config DEBUG_WQ_FORCE_RR_CPU
1477 bool "Force round-robin CPU selection for unbound work items"
1478 depends on DEBUG_KERNEL
1481 Workqueue used to implicitly guarantee that work items queued
1482 without explicit CPU specified are put on the local CPU. This
1483 guarantee is no longer true and while local CPU is still
1484 preferred work items may be put on foreign CPUs. Kernel
1485 parameter "workqueue.debug_force_rr_cpu" is added to force
1486 round-robin CPU selection to flush out usages which depend on the
1487 now broken guarantee. This config option enables the debug
1488 feature by default. When enabled, memory and cache locality will
1491 config DEBUG_BLOCK_EXT_DEVT
1492 bool "Force extended block device numbers and spread them"
1493 depends on DEBUG_KERNEL
1497 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1498 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1499 YOU ARE DOING. Distros, please enable this and fix whatever
1502 Conventionally, block device numbers are allocated from
1503 predetermined contiguous area. However, extended block area
1504 may introduce non-contiguous block device numbers. This
1505 option forces most block device numbers to be allocated from
1506 the extended space and spreads them to discover kernel or
1507 userland code paths which assume predetermined contiguous
1508 device number allocation.
1510 Note that turning on this debug option shuffles all the
1511 device numbers for all IDE and SCSI devices including libata
1512 ones, so root partition specified using device number
1513 directly (via rdev or root=MAJ:MIN) won't work anymore.
1514 Textual device names (root=/dev/sdXn) will continue to work.
1516 Say N if you are unsure.
1518 config CPU_HOTPLUG_STATE_CONTROL
1519 bool "Enable CPU hotplug state control"
1520 depends on DEBUG_KERNEL
1521 depends on HOTPLUG_CPU
1524 Allows to write steps between "offline" and "online" to the CPUs
1525 sysfs target file so states can be stepped granular. This is a debug
1526 option for now as the hotplug machinery cannot be stopped and
1527 restarted at arbitrary points yet.
1529 Say N if your are unsure.
1532 bool "Latency measuring infrastructure"
1533 depends on DEBUG_KERNEL
1534 depends on STACKTRACE_SUPPORT
1536 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
1543 Enable this option if you want to use the LatencyTOP tool
1544 to find out which userspace is blocking on what kernel operations.
1546 source "kernel/trace/Kconfig"
1548 config PROVIDE_OHCI1394_DMA_INIT
1549 bool "Remote debugging over FireWire early on boot"
1550 depends on PCI && X86
1552 If you want to debug problems which hang or crash the kernel early
1553 on boot and the crashing machine has a FireWire port, you can use
1554 this feature to remotely access the memory of the crashed machine
1555 over FireWire. This employs remote DMA as part of the OHCI1394
1556 specification which is now the standard for FireWire controllers.
1558 With remote DMA, you can monitor the printk buffer remotely using
1559 firescope and access all memory below 4GB using fireproxy from gdb.
1560 Even controlling a kernel debugger is possible using remote DMA.
1564 If ohci1394_dma=early is used as boot parameter, it will initialize
1565 all OHCI1394 controllers which are found in the PCI config space.
1567 As all changes to the FireWire bus such as enabling and disabling
1568 devices cause a bus reset and thereby disable remote DMA for all
1569 devices, be sure to have the cable plugged and FireWire enabled on
1570 the debugging host before booting the debug target for debugging.
1572 This code (~1k) is freed after boot. By then, the firewire stack
1573 in charge of the OHCI-1394 controllers should be used instead.
1575 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1577 source "samples/Kconfig"
1579 source "lib/Kconfig.kcsan"
1581 config ARCH_HAS_DEVMEM_IS_ALLOWED
1584 config STRICT_DEVMEM
1585 bool "Filter access to /dev/mem"
1586 depends on MMU && DEVMEM
1587 depends on ARCH_HAS_DEVMEM_IS_ALLOWED
1588 default y if PPC || X86 || ARM64
1590 If this option is disabled, you allow userspace (root) access to all
1591 of memory, including kernel and userspace memory. Accidental
1592 access to this is obviously disastrous, but specific access can
1593 be used by people debugging the kernel. Note that with PAT support
1594 enabled, even in this case there are restrictions on /dev/mem
1595 use due to the cache aliasing requirements.
1597 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1598 file only allows userspace access to PCI space and the BIOS code and
1599 data regions. This is sufficient for dosemu and X and all common
1604 config IO_STRICT_DEVMEM
1605 bool "Filter I/O access to /dev/mem"
1606 depends on STRICT_DEVMEM
1608 If this option is disabled, you allow userspace (root) access to all
1609 io-memory regardless of whether a driver is actively using that
1610 range. Accidental access to this is obviously disastrous, but
1611 specific access can be used by people debugging kernel drivers.
1613 If this option is switched on, the /dev/mem file only allows
1614 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1615 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1616 if the driver using a given range cannot be disabled.
1620 menu "$(SRCARCH) Debugging"
1622 source "arch/$(SRCARCH)/Kconfig.debug"
1626 menu "Kernel Testing and Coverage"
1628 source "lib/kunit/Kconfig"
1630 config NOTIFIER_ERROR_INJECTION
1631 tristate "Notifier error injection"
1632 depends on DEBUG_KERNEL
1635 This option provides the ability to inject artificial errors to
1636 specified notifier chain callbacks. It is useful to test the error
1637 handling of notifier call chain failures.
1641 config PM_NOTIFIER_ERROR_INJECT
1642 tristate "PM notifier error injection module"
1643 depends on PM && NOTIFIER_ERROR_INJECTION
1644 default m if PM_DEBUG
1646 This option provides the ability to inject artificial errors to
1647 PM notifier chain callbacks. It is controlled through debugfs
1648 interface /sys/kernel/debug/notifier-error-inject/pm
1650 If the notifier call chain should be failed with some events
1651 notified, write the error code to "actions/<notifier event>/error".
1653 Example: Inject PM suspend error (-12 = -ENOMEM)
1655 # cd /sys/kernel/debug/notifier-error-inject/pm/
1656 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1657 # echo mem > /sys/power/state
1658 bash: echo: write error: Cannot allocate memory
1660 To compile this code as a module, choose M here: the module will
1661 be called pm-notifier-error-inject.
1665 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1666 tristate "OF reconfig notifier error injection module"
1667 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1669 This option provides the ability to inject artificial errors to
1670 OF reconfig notifier chain callbacks. It is controlled
1671 through debugfs interface under
1672 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1674 If the notifier call chain should be failed with some events
1675 notified, write the error code to "actions/<notifier event>/error".
1677 To compile this code as a module, choose M here: the module will
1678 be called of-reconfig-notifier-error-inject.
1682 config NETDEV_NOTIFIER_ERROR_INJECT
1683 tristate "Netdev notifier error injection module"
1684 depends on NET && NOTIFIER_ERROR_INJECTION
1686 This option provides the ability to inject artificial errors to
1687 netdevice notifier chain callbacks. It is controlled through debugfs
1688 interface /sys/kernel/debug/notifier-error-inject/netdev
1690 If the notifier call chain should be failed with some events
1691 notified, write the error code to "actions/<notifier event>/error".
1693 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1695 # cd /sys/kernel/debug/notifier-error-inject/netdev
1696 # echo -22 > actions/NETDEV_CHANGEMTU/error
1697 # ip link set eth0 mtu 1024
1698 RTNETLINK answers: Invalid argument
1700 To compile this code as a module, choose M here: the module will
1701 be called netdev-notifier-error-inject.
1705 config FUNCTION_ERROR_INJECTION
1707 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1709 config FAULT_INJECTION
1710 bool "Fault-injection framework"
1711 depends on DEBUG_KERNEL
1713 Provide fault-injection framework.
1714 For more details, see Documentation/fault-injection/.
1717 bool "Fault-injection capability for kmalloc"
1718 depends on FAULT_INJECTION
1719 depends on SLAB || SLUB
1721 Provide fault-injection capability for kmalloc.
1723 config FAIL_PAGE_ALLOC
1724 bool "Fault-injection capability for alloc_pages()"
1725 depends on FAULT_INJECTION
1727 Provide fault-injection capability for alloc_pages().
1729 config FAIL_MAKE_REQUEST
1730 bool "Fault-injection capability for disk IO"
1731 depends on FAULT_INJECTION && BLOCK
1733 Provide fault-injection capability for disk IO.
1735 config FAIL_IO_TIMEOUT
1736 bool "Fault-injection capability for faking disk interrupts"
1737 depends on FAULT_INJECTION && BLOCK
1739 Provide fault-injection capability on end IO handling. This
1740 will make the block layer "forget" an interrupt as configured,
1741 thus exercising the error handling.
1743 Only works with drivers that use the generic timeout handling,
1744 for others it wont do anything.
1747 bool "Fault-injection capability for futexes"
1749 depends on FAULT_INJECTION && FUTEX
1751 Provide fault-injection capability for futexes.
1753 config FAULT_INJECTION_DEBUG_FS
1754 bool "Debugfs entries for fault-injection capabilities"
1755 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1757 Enable configuration of fault-injection capabilities via debugfs.
1759 config FAIL_FUNCTION
1760 bool "Fault-injection capability for functions"
1761 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1763 Provide function-based fault-injection capability.
1764 This will allow you to override a specific function with a return
1765 with given return value. As a result, function caller will see
1766 an error value and have to handle it. This is useful to test the
1767 error handling in various subsystems.
1769 config FAIL_MMC_REQUEST
1770 bool "Fault-injection capability for MMC IO"
1771 depends on FAULT_INJECTION_DEBUG_FS && MMC
1773 Provide fault-injection capability for MMC IO.
1774 This will make the mmc core return data errors. This is
1775 useful to test the error handling in the mmc block device
1776 and to test how the mmc host driver handles retries from
1779 config FAULT_INJECTION_STACKTRACE_FILTER
1780 bool "stacktrace filter for fault-injection capabilities"
1781 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1784 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
1786 Provide stacktrace filter for fault-injection capabilities
1788 config ARCH_HAS_KCOV
1791 An architecture should select this when it can successfully
1792 build and run with CONFIG_KCOV. This typically requires
1793 disabling instrumentation for some early boot code.
1795 config CC_HAS_SANCOV_TRACE_PC
1796 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1800 bool "Code coverage for fuzzing"
1801 depends on ARCH_HAS_KCOV
1802 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1804 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1806 KCOV exposes kernel code coverage information in a form suitable
1807 for coverage-guided fuzzing (randomized testing).
1809 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1810 different machines and across reboots. If you need stable PC values,
1811 disable RANDOMIZE_BASE.
1813 For more details, see Documentation/dev-tools/kcov.rst.
1815 config KCOV_ENABLE_COMPARISONS
1816 bool "Enable comparison operands collection by KCOV"
1818 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
1820 KCOV also exposes operands of every comparison in the instrumented
1821 code along with operand sizes and PCs of the comparison instructions.
1822 These operands can be used by fuzzing engines to improve the quality
1823 of fuzzing coverage.
1825 config KCOV_INSTRUMENT_ALL
1826 bool "Instrument all code by default"
1830 If you are doing generic system call fuzzing (like e.g. syzkaller),
1831 then you will want to instrument the whole kernel and you should
1832 say y here. If you are doing more targeted fuzzing (like e.g.
1833 filesystem fuzzing with AFL) then you will want to enable coverage
1834 for more specific subsets of files, and should say n here.
1836 config KCOV_IRQ_AREA_SIZE
1837 hex "Size of interrupt coverage collection area in words"
1841 KCOV uses preallocated per-cpu areas to collect coverage from
1842 soft interrupts. This specifies the size of those areas in the
1843 number of unsigned long words.
1845 menuconfig RUNTIME_TESTING_MENU
1846 bool "Runtime Testing"
1849 if RUNTIME_TESTING_MENU
1852 tristate "Linux Kernel Dump Test Tool Module"
1855 This module enables testing of the different dumping mechanisms by
1856 inducing system failures at predefined crash points.
1857 If you don't need it: say N
1858 Choose M here to compile this code as a module. The module will be
1861 Documentation on how to use the module can be found in
1862 Documentation/fault-injection/provoke-crashes.rst
1864 config TEST_LIST_SORT
1865 tristate "Linked list sorting test"
1866 depends on DEBUG_KERNEL || m
1868 Enable this to turn on 'list_sort()' function test. This test is
1869 executed only once during system boot (so affects only boot time),
1870 or at module load time.
1874 config TEST_MIN_HEAP
1875 tristate "Min heap test"
1876 depends on DEBUG_KERNEL || m
1878 Enable this to turn on min heap function tests. This test is
1879 executed only once during system boot (so affects only boot time),
1880 or at module load time.
1885 tristate "Array-based sort test"
1886 depends on DEBUG_KERNEL || m
1888 This option enables the self-test function of 'sort()' at boot,
1889 or at module load time.
1893 config KPROBES_SANITY_TEST
1894 bool "Kprobes sanity tests"
1895 depends on DEBUG_KERNEL
1898 This option provides for testing basic kprobes functionality on
1899 boot. Samples of kprobe and kretprobe are inserted and
1900 verified for functionality.
1902 Say N if you are unsure.
1904 config BACKTRACE_SELF_TEST
1905 tristate "Self test for the backtrace code"
1906 depends on DEBUG_KERNEL
1908 This option provides a kernel module that can be used to test
1909 the kernel stack backtrace code. This option is not useful
1910 for distributions or general kernels, but only for kernel
1911 developers working on architecture code.
1913 Note that if you want to also test saved backtraces, you will
1914 have to enable STACKTRACE as well.
1916 Say N if you are unsure.
1919 tristate "Red-Black tree test"
1920 depends on DEBUG_KERNEL
1922 A benchmark measuring the performance of the rbtree library.
1923 Also includes rbtree invariant checks.
1925 config REED_SOLOMON_TEST
1926 tristate "Reed-Solomon library test"
1927 depends on DEBUG_KERNEL || m
1929 select REED_SOLOMON_ENC16
1930 select REED_SOLOMON_DEC16
1932 This option enables the self-test function of rslib at boot,
1933 or at module load time.
1937 config INTERVAL_TREE_TEST
1938 tristate "Interval tree test"
1939 depends on DEBUG_KERNEL
1940 select INTERVAL_TREE
1942 A benchmark measuring the performance of the interval tree library
1945 tristate "Per cpu operations test"
1946 depends on m && DEBUG_KERNEL
1948 Enable this option to build test module which validates per-cpu
1953 config ATOMIC64_SELFTEST
1954 tristate "Perform an atomic64_t self-test"
1956 Enable this option to test the atomic64_t functions at boot or
1957 at module load time.
1961 config ASYNC_RAID6_TEST
1962 tristate "Self test for hardware accelerated raid6 recovery"
1963 depends on ASYNC_RAID6_RECOV
1966 This is a one-shot self test that permutes through the
1967 recovery of all the possible two disk failure scenarios for a
1968 N-disk array. Recovery is performed with the asynchronous
1969 raid6 recovery routines, and will optionally use an offload
1970 engine if one is available.
1975 tristate "Test functions located in the hexdump module at runtime"
1977 config TEST_STRING_HELPERS
1978 tristate "Test functions located in the string_helpers module at runtime"
1981 tristate "Test strscpy*() family of functions at runtime"
1984 tristate "Test kstrto*() family of functions at runtime"
1987 tristate "Test printf() family of functions at runtime"
1990 tristate "Test bitmap_*() family of functions at runtime"
1992 Enable this option to test the bitmap functions at boot.
1996 config TEST_BITFIELD
1997 tristate "Test bitfield functions at runtime"
1999 Enable this option to test the bitfield functions at boot.
2004 tristate "Test functions located in the uuid module at runtime"
2007 tristate "Test the XArray code at runtime"
2009 config TEST_OVERFLOW
2010 tristate "Test check_*_overflow() functions at runtime"
2012 config TEST_RHASHTABLE
2013 tristate "Perform selftest on resizable hash table"
2015 Enable this option to test the rhashtable functions at boot.
2020 tristate "Perform selftest on hash functions"
2022 Enable this option to test the kernel's integer (<linux/hash.h>),
2023 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
2024 hash functions on boot (or module load).
2026 This is intended to help people writing architecture-specific
2027 optimized versions. If unsure, say N.
2030 tristate "Perform selftest on IDA functions"
2033 tristate "Perform selftest on priority array manager"
2036 Enable this option to test priority array manager on boot
2041 config TEST_IRQ_TIMINGS
2042 bool "IRQ timings selftest"
2043 depends on IRQ_TIMINGS
2045 Enable this option to test the irq timings code on boot.
2050 tristate "Test module loading with 'hello world' module"
2053 This builds the "test_module" module that emits "Hello, world"
2054 on printk when loaded. It is designed to be used for basic
2055 evaluation of the module loading subsystem (for example when
2056 validating module verification). It lacks any extra dependencies,
2057 and will not normally be loaded by the system unless explicitly
2063 tristate "Test module for compilation of bitops operations"
2066 This builds the "test_bitops" module that is much like the
2067 TEST_LKM module except that it does a basic exercise of the
2068 set/clear_bit macros and get_count_order/long to make sure there are
2069 no compiler warnings from C=1 sparse checker or -Wextra
2070 compilations. It has no dependencies and doesn't run or load unless
2071 explicitly requested by name. for example: modprobe test_bitops.
2076 tristate "Test module for stress/performance analysis of vmalloc allocator"
2081 This builds the "test_vmalloc" module that should be used for
2082 stress and performance analysis. So, any new change for vmalloc
2083 subsystem can be evaluated from performance and stability point
2088 config TEST_USER_COPY
2089 tristate "Test user/kernel boundary protections"
2092 This builds the "test_user_copy" module that runs sanity checks
2093 on the copy_to/from_user infrastructure, making sure basic
2094 user/kernel boundary testing is working. If it fails to load,
2095 a regression has been detected in the user/kernel memory boundary
2101 tristate "Test BPF filter functionality"
2104 This builds the "test_bpf" module that runs various test vectors
2105 against the BPF interpreter or BPF JIT compiler depending on the
2106 current setting. This is in particular useful for BPF JIT compiler
2107 development, but also to run regression tests against changes in
2108 the interpreter code. It also enables test stubs for eBPF maps and
2109 verifier used by user space verifier testsuite.
2113 config TEST_BLACKHOLE_DEV
2114 tristate "Test blackhole netdev functionality"
2117 This builds the "test_blackhole_dev" module that validates the
2118 data path through this blackhole netdev.
2122 config FIND_BIT_BENCHMARK
2123 tristate "Test find_bit functions"
2125 This builds the "test_find_bit" module that measure find_*_bit()
2126 functions performance.
2130 config TEST_FIRMWARE
2131 tristate "Test firmware loading via userspace interface"
2132 depends on FW_LOADER
2134 This builds the "test_firmware" module that creates a userspace
2135 interface for testing firmware loading. This can be used to
2136 control the triggering of firmware loading without needing an
2137 actual firmware-using device. The contents can be rechecked by
2143 tristate "sysctl test driver"
2144 depends on PROC_SYSCTL
2146 This builds the "test_sysctl" module. This driver enables to test the
2147 proc sysctl interfaces available to drivers safely without affecting
2148 production knobs which might alter system functionality.
2152 config SYSCTL_KUNIT_TEST
2153 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2155 default KUNIT_ALL_TESTS
2157 This builds the proc sysctl unit test, which runs on boot.
2158 Tests the API contract and implementation correctness of sysctl.
2159 For more information on KUnit and unit tests in general please refer
2160 to the KUnit documentation in Documentation/dev-tools/kunit/.
2164 config LIST_KUNIT_TEST
2165 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2167 default KUNIT_ALL_TESTS
2169 This builds the linked list KUnit test suite.
2170 It tests that the API and basic functionality of the list_head type
2171 and associated macros.
2173 KUnit tests run during boot and output the results to the debug log
2174 in TAP format (http://testanything.org/). Only useful for kernel devs
2175 running the KUnit test harness, and not intended for inclusion into a
2178 For more information on KUnit and unit tests in general please refer
2179 to the KUnit documentation in Documentation/dev-tools/kunit/.
2183 config LINEAR_RANGES_TEST
2184 tristate "KUnit test for linear_ranges"
2186 select LINEAR_RANGES
2188 This builds the linear_ranges unit test, which runs on boot.
2189 Tests the linear_ranges logic correctness.
2190 For more information on KUnit and unit tests in general please refer
2191 to the KUnit documentation in Documentation/dev-tools/kunit/.
2196 tristate "udelay test driver"
2198 This builds the "udelay_test" module that helps to make sure
2199 that udelay() is working properly.
2203 config TEST_STATIC_KEYS
2204 tristate "Test static keys"
2207 Test the static key interfaces.
2212 tristate "kmod stress tester"
2214 depends on NETDEVICES && NET_CORE && INET # for TUN
2221 Test the kernel's module loading mechanism: kmod. kmod implements
2222 support to load modules using the Linux kernel's usermode helper.
2223 This test provides a series of tests against kmod.
2225 Although technically you can either build test_kmod as a module or
2226 into the kernel we disallow building it into the kernel since
2227 it stress tests request_module() and this will very likely cause
2228 some issues by taking over precious threads available from other
2229 module load requests, ultimately this could be fatal.
2233 tools/testing/selftests/kmod/kmod.sh --help
2237 config TEST_DEBUG_VIRTUAL
2238 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2239 depends on DEBUG_VIRTUAL
2241 Test the kernel's ability to detect incorrect calls to
2242 virt_to_phys() done against the non-linear part of the
2243 kernel's virtual address map.
2247 config TEST_MEMCAT_P
2248 tristate "Test memcat_p() helper function"
2250 Test the memcat_p() helper for correctly merging two
2251 pointer arrays together.
2255 config TEST_LIVEPATCH
2256 tristate "Test livepatching"
2258 depends on DYNAMIC_DEBUG
2259 depends on LIVEPATCH
2262 Test kernel livepatching features for correctness. The tests will
2263 load test modules that will be livepatched in various scenarios.
2265 To run all the livepatching tests:
2267 make -C tools/testing/selftests TARGETS=livepatch run_tests
2269 Alternatively, individual tests may be invoked:
2271 tools/testing/selftests/livepatch/test-callbacks.sh
2272 tools/testing/selftests/livepatch/test-livepatch.sh
2273 tools/testing/selftests/livepatch/test-shadow-vars.sh
2278 tristate "Perform selftest on object aggreration manager"
2282 Enable this option to test object aggregation manager on boot
2286 config TEST_STACKINIT
2287 tristate "Test level of stack variable initialization"
2289 Test if the kernel is zero-initializing stack variables and
2290 padding. Coverage is controlled by compiler flags,
2291 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2292 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2297 tristate "Test heap/page initialization"
2299 Test if the kernel is zero-initializing heap and page allocations.
2300 This can be useful to test init_on_alloc and init_on_free features.
2305 tristate "Test HMM (Heterogeneous Memory Management)"
2306 depends on TRANSPARENT_HUGEPAGE
2307 depends on DEVICE_PRIVATE
2311 This is a pseudo device driver solely for testing HMM.
2312 Say M here if you want to build the HMM test module.
2313 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2318 tristate "Test floating point operations in kernel space"
2319 depends on X86 && !KCOV_INSTRUMENT_ALL
2321 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2322 which will trigger a sequence of floating point operations. This is used
2323 for self-testing floating point control register setting in
2328 endif # RUNTIME_TESTING_MENU
2333 This option adds a kernel parameter 'memtest', which allows memtest
2335 memtest=0, mean disabled; -- default
2336 memtest=1, mean do 1 test pattern;
2338 memtest=17, mean do 17 test patterns.
2339 If you are unsure how to answer this question, answer N.
2343 config HYPERV_TESTING
2344 bool "Microsoft Hyper-V driver testing"
2346 depends on HYPERV && DEBUG_FS
2348 Select this option to enable Hyper-V vmbus testing.
2350 endmenu # "Kernel Testing and Coverage"
2352 endmenu # Kernel hacking