0001 # SPDX-License-Identifier: GPL-2.0-only
0002 menu "Kernel hacking"
0003
0004 menu "printk and dmesg options"
0005
0006 config PRINTK_TIME
0007 bool "Show timing information on printks"
0008 depends on PRINTK
0009 help
0010 Selecting this option causes time stamps of the printk()
0011 messages to be added to the output of the syslog() system
0012 call and at the console.
0013
0014 The timestamp is always recorded internally, and exported
0015 to /dev/kmsg. This flag just specifies if the timestamp should
0016 be included, not that the timestamp is recorded.
0017
0018 The behavior is also controlled by the kernel command line
0019 parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
0020
0021 config PRINTK_CALLER
0022 bool "Show caller information on printks"
0023 depends on PRINTK
0024 help
0025 Selecting this option causes printk() to add a caller "thread id" (if
0026 in task context) or a caller "processor id" (if not in task context)
0027 to every message.
0028
0029 This option is intended for environments where multiple threads
0030 concurrently call printk() for many times, for it is difficult to
0031 interpret without knowing where these lines (or sometimes individual
0032 line which was divided into multiple lines due to race) came from.
0033
0034 Since toggling after boot makes the code racy, currently there is
0035 no option to enable/disable at the kernel command line parameter or
0036 sysfs interface.
0037
0038 config STACKTRACE_BUILD_ID
0039 bool "Show build ID information in stacktraces"
0040 depends on PRINTK
0041 help
0042 Selecting this option adds build ID information for symbols in
0043 stacktraces printed with the printk format '%p[SR]b'.
0044
0045 This option is intended for distros where debuginfo is not easily
0046 accessible but can be downloaded given the build ID of the vmlinux or
0047 kernel module where the function is located.
0048
0049 config CONSOLE_LOGLEVEL_DEFAULT
0050 int "Default console loglevel (1-15)"
0051 range 1 15
0052 default "7"
0053 help
0054 Default loglevel to determine what will be printed on the console.
0055
0056 Setting a default here is equivalent to passing in loglevel=<x> in
0057 the kernel bootargs. loglevel=<x> continues to override whatever
0058 value is specified here as well.
0059
0060 Note: This does not affect the log level of un-prefixed printk()
0061 usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
0062 option.
0063
0064 config CONSOLE_LOGLEVEL_QUIET
0065 int "quiet console loglevel (1-15)"
0066 range 1 15
0067 default "4"
0068 help
0069 loglevel to use when "quiet" is passed on the kernel commandline.
0070
0071 When "quiet" is passed on the kernel commandline this loglevel
0072 will be used as the loglevel. IOW passing "quiet" will be the
0073 equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
0074
0075 config MESSAGE_LOGLEVEL_DEFAULT
0076 int "Default message log level (1-7)"
0077 range 1 7
0078 default "4"
0079 help
0080 Default log level for printk statements with no specified priority.
0081
0082 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
0083 that are auditing their logs closely may want to set it to a lower
0084 priority.
0085
0086 Note: This does not affect what message level gets printed on the console
0087 by default. To change that, use loglevel=<x> in the kernel bootargs,
0088 or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
0089
0090 config BOOT_PRINTK_DELAY
0091 bool "Delay each boot printk message by N milliseconds"
0092 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
0093 help
0094 This build option allows you to read kernel boot messages
0095 by inserting a short delay after each one. The delay is
0096 specified in milliseconds on the kernel command line,
0097 using "boot_delay=N".
0098
0099 It is likely that you would also need to use "lpj=M" to preset
0100 the "loops per jiffie" value.
0101 See a previous boot log for the "lpj" value to use for your
0102 system, and then set "lpj=M" before setting "boot_delay=N".
0103 NOTE: Using this option may adversely affect SMP systems.
0104 I.e., processors other than the first one may not boot up.
0105 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
0106 what it believes to be lockup conditions.
0107
0108 config DYNAMIC_DEBUG
0109 bool "Enable dynamic printk() support"
0110 default n
0111 depends on PRINTK
0112 depends on (DEBUG_FS || PROC_FS)
0113 select DYNAMIC_DEBUG_CORE
0114 help
0115
0116 Compiles debug level messages into the kernel, which would not
0117 otherwise be available at runtime. These messages can then be
0118 enabled/disabled based on various levels of scope - per source file,
0119 function, module, format string, and line number. This mechanism
0120 implicitly compiles in all pr_debug() and dev_dbg() calls, which
0121 enlarges the kernel text size by about 2%.
0122
0123 If a source file is compiled with DEBUG flag set, any
0124 pr_debug() calls in it are enabled by default, but can be
0125 disabled at runtime as below. Note that DEBUG flag is
0126 turned on by many CONFIG_*DEBUG* options.
0127
0128 Usage:
0129
0130 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
0131 which is contained in the 'debugfs' filesystem or procfs.
0132 Thus, the debugfs or procfs filesystem must first be mounted before
0133 making use of this feature.
0134 We refer the control file as: <debugfs>/dynamic_debug/control. This
0135 file contains a list of the debug statements that can be enabled. The
0136 format for each line of the file is:
0137
0138 filename:lineno [module]function flags format
0139
0140 filename : source file of the debug statement
0141 lineno : line number of the debug statement
0142 module : module that contains the debug statement
0143 function : function that contains the debug statement
0144 flags : '=p' means the line is turned 'on' for printing
0145 format : the format used for the debug statement
0146
0147 From a live system:
0148
0149 nullarbor:~ # cat <debugfs>/dynamic_debug/control
0150 # filename:lineno [module]function flags format
0151 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
0152 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
0153 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
0154
0155 Example usage:
0156
0157 // enable the message at line 1603 of file svcsock.c
0158 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
0159 <debugfs>/dynamic_debug/control
0160
0161 // enable all the messages in file svcsock.c
0162 nullarbor:~ # echo -n 'file svcsock.c +p' >
0163 <debugfs>/dynamic_debug/control
0164
0165 // enable all the messages in the NFS server module
0166 nullarbor:~ # echo -n 'module nfsd +p' >
0167 <debugfs>/dynamic_debug/control
0168
0169 // enable all 12 messages in the function svc_process()
0170 nullarbor:~ # echo -n 'func svc_process +p' >
0171 <debugfs>/dynamic_debug/control
0172
0173 // disable all 12 messages in the function svc_process()
0174 nullarbor:~ # echo -n 'func svc_process -p' >
0175 <debugfs>/dynamic_debug/control
0176
0177 See Documentation/admin-guide/dynamic-debug-howto.rst for additional
0178 information.
0179
0180 config DYNAMIC_DEBUG_CORE
0181 bool "Enable core function of dynamic debug support"
0182 depends on PRINTK
0183 depends on (DEBUG_FS || PROC_FS)
0184 help
0185 Enable core functional support of dynamic debug. It is useful
0186 when you want to tie dynamic debug to your kernel modules with
0187 DYNAMIC_DEBUG_MODULE defined for each of them, especially for
0188 the case of embedded system where the kernel image size is
0189 sensitive for people.
0190
0191 config SYMBOLIC_ERRNAME
0192 bool "Support symbolic error names in printf"
0193 default y if PRINTK
0194 help
0195 If you say Y here, the kernel's printf implementation will
0196 be able to print symbolic error names such as ENOSPC instead
0197 of the number 28. It makes the kernel image slightly larger
0198 (about 3KB), but can make the kernel logs easier to read.
0199
0200 config DEBUG_BUGVERBOSE
0201 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
0202 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
0203 default y
0204 help
0205 Say Y here to make BUG() panics output the file name and line number
0206 of the BUG call as well as the EIP and oops trace. This aids
0207 debugging but costs about 70-100K of memory.
0208
0209 endmenu # "printk and dmesg options"
0210
0211 config DEBUG_KERNEL
0212 bool "Kernel debugging"
0213 help
0214 Say Y here if you are developing drivers or trying to debug and
0215 identify kernel problems.
0216
0217 config DEBUG_MISC
0218 bool "Miscellaneous debug code"
0219 default DEBUG_KERNEL
0220 depends on DEBUG_KERNEL
0221 help
0222 Say Y here if you need to enable miscellaneous debug code that should
0223 be under a more specific debug option but isn't.
0224
0225 menu "Compile-time checks and compiler options"
0226
0227 config DEBUG_INFO
0228 bool
0229 help
0230 A kernel debug info option other than "None" has been selected
0231 in the "Debug information" choice below, indicating that debug
0232 information will be generated for build targets.
0233
0234 choice
0235 prompt "Debug information"
0236 depends on DEBUG_KERNEL
0237 help
0238 Selecting something other than "None" results in a kernel image
0239 that will include debugging info resulting in a larger kernel image.
0240 This adds debug symbols to the kernel and modules (gcc -g), and
0241 is needed if you intend to use kernel crashdump or binary object
0242 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
0243
0244 Choose which version of DWARF debug info to emit. If unsure,
0245 select "Toolchain default".
0246
0247 config DEBUG_INFO_NONE
0248 bool "Disable debug information"
0249 help
0250 Do not build the kernel with debugging information, which will
0251 result in a faster and smaller build.
0252
0253 config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
0254 bool "Rely on the toolchain's implicit default DWARF version"
0255 select DEBUG_INFO
0256 help
0257 The implicit default version of DWARF debug info produced by a
0258 toolchain changes over time.
0259
0260 This can break consumers of the debug info that haven't upgraded to
0261 support newer revisions, and prevent testing newer versions, but
0262 those should be less common scenarios.
0263
0264 config DEBUG_INFO_DWARF4
0265 bool "Generate DWARF Version 4 debuginfo"
0266 select DEBUG_INFO
0267 depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)))
0268 help
0269 Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2
0270 if using clang without clang's integrated assembler, and gdb 7.0+.
0271
0272 If you have consumers of DWARF debug info that are not ready for
0273 newer revisions of DWARF, you may wish to choose this or have your
0274 config select this.
0275
0276 config DEBUG_INFO_DWARF5
0277 bool "Generate DWARF Version 5 debuginfo"
0278 select DEBUG_INFO
0279 depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502)))
0280 help
0281 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
0282 5.0+ accepts the -gdwarf-5 flag but only had partial support for some
0283 draft features until 7.0), and gdb 8.0+.
0284
0285 Changes to the structure of debug info in Version 5 allow for around
0286 15-18% savings in resulting image and debug info section sizes as
0287 compared to DWARF Version 4. DWARF Version 5 standardizes previous
0288 extensions such as accelerators for symbol indexing and the format
0289 for fission (.dwo/.dwp) files. Users may not want to select this
0290 config if they rely on tooling that has not yet been updated to
0291 support DWARF Version 5.
0292
0293 endchoice # "Debug information"
0294
0295 if DEBUG_INFO
0296
0297 config DEBUG_INFO_REDUCED
0298 bool "Reduce debugging information"
0299 help
0300 If you say Y here gcc is instructed to generate less debugging
0301 information for structure types. This means that tools that
0302 need full debugging information (like kgdb or systemtap) won't
0303 be happy. But if you merely need debugging information to
0304 resolve line numbers there is no loss. Advantage is that
0305 build directory object sizes shrink dramatically over a full
0306 DEBUG_INFO build and compile times are reduced too.
0307 Only works with newer gcc versions.
0308
0309 config DEBUG_INFO_COMPRESSED
0310 bool "Compressed debugging information"
0311 depends on $(cc-option,-gz=zlib)
0312 depends on $(ld-option,--compress-debug-sections=zlib)
0313 help
0314 Compress the debug information using zlib. Requires GCC 5.0+ or Clang
0315 5.0+, binutils 2.26+, and zlib.
0316
0317 Users of dpkg-deb via scripts/package/builddeb may find an increase in
0318 size of their debug .deb packages with this config set, due to the
0319 debug info being compressed with zlib, then the object files being
0320 recompressed with a different compression scheme. But this is still
0321 preferable to setting $KDEB_COMPRESS to "none" which would be even
0322 larger.
0323
0324 config DEBUG_INFO_SPLIT
0325 bool "Produce split debuginfo in .dwo files"
0326 depends on $(cc-option,-gsplit-dwarf)
0327 help
0328 Generate debug info into separate .dwo files. This significantly
0329 reduces the build directory size for builds with DEBUG_INFO,
0330 because it stores the information only once on disk in .dwo
0331 files instead of multiple times in object files and executables.
0332 In addition the debug information is also compressed.
0333
0334 Requires recent gcc (4.7+) and recent gdb/binutils.
0335 Any tool that packages or reads debug information would need
0336 to know about the .dwo files and include them.
0337 Incompatible with older versions of ccache.
0338
0339 config DEBUG_INFO_BTF
0340 bool "Generate BTF typeinfo"
0341 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
0342 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
0343 depends on BPF_SYSCALL
0344 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121
0345 help
0346 Generate deduplicated BTF type information from DWARF debug info.
0347 Turning this on expects presence of pahole tool, which will convert
0348 DWARF type info into equivalent deduplicated BTF type info.
0349
0350 config PAHOLE_HAS_SPLIT_BTF
0351 def_bool PAHOLE_VERSION >= 119
0352
0353 config PAHOLE_HAS_BTF_TAG
0354 def_bool PAHOLE_VERSION >= 123
0355 depends on CC_IS_CLANG
0356 help
0357 Decide whether pahole emits btf_tag attributes (btf_type_tag and
0358 btf_decl_tag) or not. Currently only clang compiler implements
0359 these attributes, so make the config depend on CC_IS_CLANG.
0360
0361 config DEBUG_INFO_BTF_MODULES
0362 def_bool y
0363 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
0364 help
0365 Generate compact split BTF type information for kernel modules.
0366
0367 config MODULE_ALLOW_BTF_MISMATCH
0368 bool "Allow loading modules with non-matching BTF type info"
0369 depends on DEBUG_INFO_BTF_MODULES
0370 help
0371 For modules whose split BTF does not match vmlinux, load without
0372 BTF rather than refusing to load. The default behavior with
0373 module BTF enabled is to reject modules with such mismatches;
0374 this option will still load module BTF where possible but ignore
0375 it when a mismatch is found.
0376
0377 config GDB_SCRIPTS
0378 bool "Provide GDB scripts for kernel debugging"
0379 help
0380 This creates the required links to GDB helper scripts in the
0381 build directory. If you load vmlinux into gdb, the helper
0382 scripts will be automatically imported by gdb as well, and
0383 additional functions are available to analyze a Linux kernel
0384 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
0385 for further details.
0386
0387 endif # DEBUG_INFO
0388
0389 config FRAME_WARN
0390 int "Warn for stack frames larger than"
0391 range 0 8192
0392 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
0393 default 2048 if PARISC
0394 default 1536 if (!64BIT && XTENSA)
0395 default 1024 if !64BIT
0396 default 2048 if 64BIT
0397 help
0398 Tell gcc to warn at build time for stack frames larger than this.
0399 Setting this too low will cause a lot of warnings.
0400 Setting it to 0 disables the warning.
0401
0402 config STRIP_ASM_SYMS
0403 bool "Strip assembler-generated symbols during link"
0404 default n
0405 help
0406 Strip internal assembler-generated symbols during a link (symbols
0407 that look like '.Lxxx') so they don't pollute the output of
0408 get_wchan() and suchlike.
0409
0410 config READABLE_ASM
0411 bool "Generate readable assembler code"
0412 depends on DEBUG_KERNEL
0413 depends on CC_IS_GCC
0414 help
0415 Disable some compiler optimizations that tend to generate human unreadable
0416 assembler output. This may make the kernel slightly slower, but it helps
0417 to keep kernel developers who have to stare a lot at assembler listings
0418 sane.
0419
0420 config HEADERS_INSTALL
0421 bool "Install uapi headers to usr/include"
0422 depends on !UML
0423 help
0424 This option will install uapi headers (headers exported to user-space)
0425 into the usr/include directory for use during the kernel build.
0426 This is unneeded for building the kernel itself, but needed for some
0427 user-space program samples. It is also needed by some features such
0428 as uapi header sanity checks.
0429
0430 config DEBUG_SECTION_MISMATCH
0431 bool "Enable full Section mismatch analysis"
0432 depends on CC_IS_GCC
0433 help
0434 The section mismatch analysis checks if there are illegal
0435 references from one section to another section.
0436 During linktime or runtime, some sections are dropped;
0437 any use of code/data previously in these sections would
0438 most likely result in an oops.
0439 In the code, functions and variables are annotated with
0440 __init,, etc. (see the full list in include/linux/init.h),
0441 which results in the code/data being placed in specific sections.
0442 The section mismatch analysis is always performed after a full
0443 kernel build, and enabling this option causes the following
0444 additional step to occur:
0445 - Add the option -fno-inline-functions-called-once to gcc commands.
0446 When inlining a function annotated with __init in a non-init
0447 function, we would lose the section information and thus
0448 the analysis would not catch the illegal reference.
0449 This option tells gcc to inline less (but it does result in
0450 a larger kernel).
0451
0452 config SECTION_MISMATCH_WARN_ONLY
0453 bool "Make section mismatch errors non-fatal"
0454 default y
0455 help
0456 If you say N here, the build process will fail if there are any
0457 section mismatch, instead of just throwing warnings.
0458
0459 If unsure, say Y.
0460
0461 config DEBUG_FORCE_FUNCTION_ALIGN_64B
0462 bool "Force all function address 64B aligned"
0463 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC)
0464 help
0465 There are cases that a commit from one domain changes the function
0466 address alignment of other domains, and cause magic performance
0467 bump (regression or improvement). Enable this option will help to
0468 verify if the bump is caused by function alignment changes, while
0469 it will slightly increase the kernel size and affect icache usage.
0470
0471 It is mainly for debug and performance tuning use.
0472
0473 #
0474 # Select this config option from the architecture Kconfig, if it
0475 # is preferred to always offer frame pointers as a config
0476 # option on the architecture (regardless of KERNEL_DEBUG):
0477 #
0478 config ARCH_WANT_FRAME_POINTERS
0479 bool
0480
0481 config FRAME_POINTER
0482 bool "Compile the kernel with frame pointers"
0483 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
0484 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
0485 help
0486 If you say Y here the resulting kernel image will be slightly
0487 larger and slower, but it gives very useful debugging information
0488 in case of kernel bugs. (precise oopses/stacktraces/warnings)
0489
0490 config OBJTOOL
0491 bool
0492
0493 config STACK_VALIDATION
0494 bool "Compile-time stack metadata validation"
0495 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER
0496 select OBJTOOL
0497 default n
0498 help
0499 Validate frame pointer rules at compile-time. This helps ensure that
0500 runtime stack traces are more reliable.
0501
0502 For more information, see
0503 tools/objtool/Documentation/objtool.txt.
0504
0505 config NOINSTR_VALIDATION
0506 bool
0507 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY
0508 select OBJTOOL
0509 default y
0510
0511 config VMLINUX_MAP
0512 bool "Generate vmlinux.map file when linking"
0513 depends on EXPERT
0514 help
0515 Selecting this option will pass "-Map=vmlinux.map" to ld
0516 when linking vmlinux. That file can be useful for verifying
0517 and debugging magic section games, and for seeing which
0518 pieces of code get eliminated with
0519 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
0520
0521 config DEBUG_FORCE_WEAK_PER_CPU
0522 bool "Force weak per-cpu definitions"
0523 depends on DEBUG_KERNEL
0524 help
0525 s390 and alpha require percpu variables in modules to be
0526 defined weak to work around addressing range issue which
0527 puts the following two restrictions on percpu variable
0528 definitions.
0529
0530 1. percpu symbols must be unique whether static or not
0531 2. percpu variables can't be defined inside a function
0532
0533 To ensure that generic code follows the above rules, this
0534 option forces all percpu variables to be defined as weak.
0535
0536 endmenu # "Compiler options"
0537
0538 menu "Generic Kernel Debugging Instruments"
0539
0540 config MAGIC_SYSRQ
0541 bool "Magic SysRq key"
0542 depends on !UML
0543 help
0544 If you say Y here, you will have some control over the system even
0545 if the system crashes for example during kernel debugging (e.g., you
0546 will be able to flush the buffer cache to disk, reboot the system
0547 immediately or dump some status information). This is accomplished
0548 by pressing various keys while holding SysRq (Alt+PrintScreen). It
0549 also works on a serial console (on PC hardware at least), if you
0550 send a BREAK and then within 5 seconds a command keypress. The
0551 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
0552 Don't say Y unless you really know what this hack does.
0553
0554 config MAGIC_SYSRQ_DEFAULT_ENABLE
0555 hex "Enable magic SysRq key functions by default"
0556 depends on MAGIC_SYSRQ
0557 default 0x1
0558 help
0559 Specifies which SysRq key functions are enabled by default.
0560 This may be set to 1 or 0 to enable or disable them all, or
0561 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
0562
0563 config MAGIC_SYSRQ_SERIAL
0564 bool "Enable magic SysRq key over serial"
0565 depends on MAGIC_SYSRQ
0566 default y
0567 help
0568 Many embedded boards have a disconnected TTL level serial which can
0569 generate some garbage that can lead to spurious false sysrq detects.
0570 This option allows you to decide whether you want to enable the
0571 magic SysRq key.
0572
0573 config MAGIC_SYSRQ_SERIAL_SEQUENCE
0574 string "Char sequence that enables magic SysRq over serial"
0575 depends on MAGIC_SYSRQ_SERIAL
0576 default ""
0577 help
0578 Specifies a sequence of characters that can follow BREAK to enable
0579 SysRq on a serial console.
0580
0581 If unsure, leave an empty string and the option will not be enabled.
0582
0583 config DEBUG_FS
0584 bool "Debug Filesystem"
0585 help
0586 debugfs is a virtual file system that kernel developers use to put
0587 debugging files into. Enable this option to be able to read and
0588 write to these files.
0589
0590 For detailed documentation on the debugfs API, see
0591 Documentation/filesystems/.
0592
0593 If unsure, say N.
0594
0595 choice
0596 prompt "Debugfs default access"
0597 depends on DEBUG_FS
0598 default DEBUG_FS_ALLOW_ALL
0599 help
0600 This selects the default access restrictions for debugfs.
0601 It can be overridden with kernel command line option
0602 debugfs=[on,no-mount,off]. The restrictions apply for API access
0603 and filesystem registration.
0604
0605 config DEBUG_FS_ALLOW_ALL
0606 bool "Access normal"
0607 help
0608 No restrictions apply. Both API and filesystem registration
0609 is on. This is the normal default operation.
0610
0611 config DEBUG_FS_DISALLOW_MOUNT
0612 bool "Do not register debugfs as filesystem"
0613 help
0614 The API is open but filesystem is not loaded. Clients can still do
0615 their work and read with debug tools that do not need
0616 debugfs filesystem.
0617
0618 config DEBUG_FS_ALLOW_NONE
0619 bool "No access"
0620 help
0621 Access is off. Clients get -PERM when trying to create nodes in
0622 debugfs tree and debugfs is not registered as a filesystem.
0623 Client can then back-off or continue without debugfs access.
0624
0625 endchoice
0626
0627 source "lib/Kconfig.kgdb"
0628 source "lib/Kconfig.ubsan"
0629 source "lib/Kconfig.kcsan"
0630
0631 endmenu
0632
0633 menu "Networking Debugging"
0634
0635 source "net/Kconfig.debug"
0636
0637 endmenu # "Networking Debugging"
0638
0639 menu "Memory Debugging"
0640
0641 source "mm/Kconfig.debug"
0642
0643 config DEBUG_OBJECTS
0644 bool "Debug object operations"
0645 depends on DEBUG_KERNEL
0646 help
0647 If you say Y here, additional code will be inserted into the
0648 kernel to track the life time of various objects and validate
0649 the operations on those objects.
0650
0651 config DEBUG_OBJECTS_SELFTEST
0652 bool "Debug objects selftest"
0653 depends on DEBUG_OBJECTS
0654 help
0655 This enables the selftest of the object debug code.
0656
0657 config DEBUG_OBJECTS_FREE
0658 bool "Debug objects in freed memory"
0659 depends on DEBUG_OBJECTS
0660 help
0661 This enables checks whether a k/v free operation frees an area
0662 which contains an object which has not been deactivated
0663 properly. This can make kmalloc/kfree-intensive workloads
0664 much slower.
0665
0666 config DEBUG_OBJECTS_TIMERS
0667 bool "Debug timer objects"
0668 depends on DEBUG_OBJECTS
0669 help
0670 If you say Y here, additional code will be inserted into the
0671 timer routines to track the life time of timer objects and
0672 validate the timer operations.
0673
0674 config DEBUG_OBJECTS_WORK
0675 bool "Debug work objects"
0676 depends on DEBUG_OBJECTS
0677 help
0678 If you say Y here, additional code will be inserted into the
0679 work queue routines to track the life time of work objects and
0680 validate the work operations.
0681
0682 config DEBUG_OBJECTS_RCU_HEAD
0683 bool "Debug RCU callbacks objects"
0684 depends on DEBUG_OBJECTS
0685 help
0686 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
0687
0688 config DEBUG_OBJECTS_PERCPU_COUNTER
0689 bool "Debug percpu counter objects"
0690 depends on DEBUG_OBJECTS
0691 help
0692 If you say Y here, additional code will be inserted into the
0693 percpu counter routines to track the life time of percpu counter
0694 objects and validate the percpu counter operations.
0695
0696 config DEBUG_OBJECTS_ENABLE_DEFAULT
0697 int "debug_objects bootup default value (0-1)"
0698 range 0 1
0699 default "1"
0700 depends on DEBUG_OBJECTS
0701 help
0702 Debug objects boot parameter default value
0703
0704 config SHRINKER_DEBUG
0705 bool "Enable shrinker debugging support"
0706 depends on DEBUG_FS
0707 help
0708 Say Y to enable the shrinker debugfs interface which provides
0709 visibility into the kernel memory shrinkers subsystem.
0710 Disable it to avoid an extra memory footprint.
0711
0712 config HAVE_DEBUG_KMEMLEAK
0713 bool
0714
0715 config DEBUG_KMEMLEAK
0716 bool "Kernel memory leak detector"
0717 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
0718 select DEBUG_FS
0719 select STACKTRACE if STACKTRACE_SUPPORT
0720 select KALLSYMS
0721 select CRC32
0722 help
0723 Say Y here if you want to enable the memory leak
0724 detector. The memory allocation/freeing is traced in a way
0725 similar to the Boehm's conservative garbage collector, the
0726 difference being that the orphan objects are not freed but
0727 only shown in /sys/kernel/debug/kmemleak. Enabling this
0728 feature will introduce an overhead to memory
0729 allocations. See Documentation/dev-tools/kmemleak.rst for more
0730 details.
0731
0732 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
0733 of finding leaks due to the slab objects poisoning.
0734
0735 In order to access the kmemleak file, debugfs needs to be
0736 mounted (usually at /sys/kernel/debug).
0737
0738 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
0739 int "Kmemleak memory pool size"
0740 depends on DEBUG_KMEMLEAK
0741 range 200 1000000
0742 default 16000
0743 help
0744 Kmemleak must track all the memory allocations to avoid
0745 reporting false positives. Since memory may be allocated or
0746 freed before kmemleak is fully initialised, use a static pool
0747 of metadata objects to track such callbacks. After kmemleak is
0748 fully initialised, this memory pool acts as an emergency one
0749 if slab allocations fail.
0750
0751 config DEBUG_KMEMLEAK_TEST
0752 tristate "Simple test for the kernel memory leak detector"
0753 depends on DEBUG_KMEMLEAK && m
0754 help
0755 This option enables a module that explicitly leaks memory.
0756
0757 If unsure, say N.
0758
0759 config DEBUG_KMEMLEAK_DEFAULT_OFF
0760 bool "Default kmemleak to off"
0761 depends on DEBUG_KMEMLEAK
0762 help
0763 Say Y here to disable kmemleak by default. It can then be enabled
0764 on the command line via kmemleak=on.
0765
0766 config DEBUG_KMEMLEAK_AUTO_SCAN
0767 bool "Enable kmemleak auto scan thread on boot up"
0768 default y
0769 depends on DEBUG_KMEMLEAK
0770 help
0771 Depending on the cpu, kmemleak scan may be cpu intensive and can
0772 stall user tasks at times. This option enables/disables automatic
0773 kmemleak scan at boot up.
0774
0775 Say N here to disable kmemleak auto scan thread to stop automatic
0776 scanning. Disabling this option disables automatic reporting of
0777 memory leaks.
0778
0779 If unsure, say Y.
0780
0781 config DEBUG_STACK_USAGE
0782 bool "Stack utilization instrumentation"
0783 depends on DEBUG_KERNEL && !IA64
0784 help
0785 Enables the display of the minimum amount of free stack which each
0786 task has ever had available in the sysrq-T and sysrq-P debug output.
0787
0788 This option will slow down process creation somewhat.
0789
0790 config SCHED_STACK_END_CHECK
0791 bool "Detect stack corruption on calls to schedule()"
0792 depends on DEBUG_KERNEL
0793 default n
0794 help
0795 This option checks for a stack overrun on calls to schedule().
0796 If the stack end location is found to be over written always panic as
0797 the content of the corrupted region can no longer be trusted.
0798 This is to ensure no erroneous behaviour occurs which could result in
0799 data corruption or a sporadic crash at a later stage once the region
0800 is examined. The runtime overhead introduced is minimal.
0801
0802 config ARCH_HAS_DEBUG_VM_PGTABLE
0803 bool
0804 help
0805 An architecture should select this when it can successfully
0806 build and run DEBUG_VM_PGTABLE.
0807
0808 config DEBUG_VM
0809 bool "Debug VM"
0810 depends on DEBUG_KERNEL
0811 help
0812 Enable this to turn on extended checks in the virtual-memory system
0813 that may impact performance.
0814
0815 If unsure, say N.
0816
0817 config DEBUG_VM_VMACACHE
0818 bool "Debug VMA caching"
0819 depends on DEBUG_VM
0820 help
0821 Enable this to turn on VMA caching debug information. Doing so
0822 can cause significant overhead, so only enable it in non-production
0823 environments.
0824
0825 If unsure, say N.
0826
0827 config DEBUG_VM_RB
0828 bool "Debug VM red-black trees"
0829 depends on DEBUG_VM
0830 help
0831 Enable VM red-black tree debugging information and extra validations.
0832
0833 If unsure, say N.
0834
0835 config DEBUG_VM_PGFLAGS
0836 bool "Debug page-flags operations"
0837 depends on DEBUG_VM
0838 help
0839 Enables extra validation on page flags operations.
0840
0841 If unsure, say N.
0842
0843 config DEBUG_VM_PGTABLE
0844 bool "Debug arch page table for semantics compliance"
0845 depends on MMU
0846 depends on ARCH_HAS_DEBUG_VM_PGTABLE
0847 default y if DEBUG_VM
0848 help
0849 This option provides a debug method which can be used to test
0850 architecture page table helper functions on various platforms in
0851 verifying if they comply with expected generic MM semantics. This
0852 will help architecture code in making sure that any changes or
0853 new additions of these helpers still conform to expected
0854 semantics of the generic MM. Platforms will have to opt in for
0855 this through ARCH_HAS_DEBUG_VM_PGTABLE.
0856
0857 If unsure, say N.
0858
0859 config ARCH_HAS_DEBUG_VIRTUAL
0860 bool
0861
0862 config DEBUG_VIRTUAL
0863 bool "Debug VM translations"
0864 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
0865 help
0866 Enable some costly sanity checks in virtual to page code. This can
0867 catch mistakes with virt_to_page() and friends.
0868
0869 If unsure, say N.
0870
0871 config DEBUG_NOMMU_REGIONS
0872 bool "Debug the global anon/private NOMMU mapping region tree"
0873 depends on DEBUG_KERNEL && !MMU
0874 help
0875 This option causes the global tree of anonymous and private mapping
0876 regions to be regularly checked for invalid topology.
0877
0878 config DEBUG_MEMORY_INIT
0879 bool "Debug memory initialisation" if EXPERT
0880 default !EXPERT
0881 help
0882 Enable this for additional checks during memory initialisation.
0883 The sanity checks verify aspects of the VM such as the memory model
0884 and other information provided by the architecture. Verbose
0885 information will be printed at KERN_DEBUG loglevel depending
0886 on the mminit_loglevel= command-line option.
0887
0888 If unsure, say Y
0889
0890 config MEMORY_NOTIFIER_ERROR_INJECT
0891 tristate "Memory hotplug notifier error injection module"
0892 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION
0893 help
0894 This option provides the ability to inject artificial errors to
0895 memory hotplug notifier chain callbacks. It is controlled through
0896 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
0897
0898 If the notifier call chain should be failed with some events
0899 notified, write the error code to "actions/<notifier event>/error".
0900
0901 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
0902
0903 # cd /sys/kernel/debug/notifier-error-inject/memory
0904 # echo -12 > actions/MEM_GOING_OFFLINE/error
0905 # echo offline > /sys/devices/system/memory/memoryXXX/state
0906 bash: echo: write error: Cannot allocate memory
0907
0908 To compile this code as a module, choose M here: the module will
0909 be called memory-notifier-error-inject.
0910
0911 If unsure, say N.
0912
0913 config DEBUG_PER_CPU_MAPS
0914 bool "Debug access to per_cpu maps"
0915 depends on DEBUG_KERNEL
0916 depends on SMP
0917 help
0918 Say Y to verify that the per_cpu map being accessed has
0919 been set up. This adds a fair amount of code to kernel memory
0920 and decreases performance.
0921
0922 Say N if unsure.
0923
0924 config DEBUG_KMAP_LOCAL
0925 bool "Debug kmap_local temporary mappings"
0926 depends on DEBUG_KERNEL && KMAP_LOCAL
0927 help
0928 This option enables additional error checking for the kmap_local
0929 infrastructure. Disable for production use.
0930
0931 config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
0932 bool
0933
0934 config DEBUG_KMAP_LOCAL_FORCE_MAP
0935 bool "Enforce kmap_local temporary mappings"
0936 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
0937 select KMAP_LOCAL
0938 select DEBUG_KMAP_LOCAL
0939 help
0940 This option enforces temporary mappings through the kmap_local
0941 mechanism for non-highmem pages and on non-highmem systems.
0942 Disable this for production systems!
0943
0944 config DEBUG_HIGHMEM
0945 bool "Highmem debugging"
0946 depends on DEBUG_KERNEL && HIGHMEM
0947 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
0948 select DEBUG_KMAP_LOCAL
0949 help
0950 This option enables additional error checking for high memory
0951 systems. Disable for production systems.
0952
0953 config HAVE_DEBUG_STACKOVERFLOW
0954 bool
0955
0956 config DEBUG_STACKOVERFLOW
0957 bool "Check for stack overflows"
0958 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
0959 help
0960 Say Y here if you want to check for overflows of kernel, IRQ
0961 and exception stacks (if your architecture uses them). This
0962 option will show detailed messages if free stack space drops
0963 below a certain limit.
0964
0965 These kinds of bugs usually occur when call-chains in the
0966 kernel get too deep, especially when interrupts are
0967 involved.
0968
0969 Use this in cases where you see apparently random memory
0970 corruption, especially if it appears in 'struct thread_info'
0971
0972 If in doubt, say "N".
0973
0974 source "lib/Kconfig.kasan"
0975 source "lib/Kconfig.kfence"
0976
0977 endmenu # "Memory Debugging"
0978
0979 config DEBUG_SHIRQ
0980 bool "Debug shared IRQ handlers"
0981 depends on DEBUG_KERNEL
0982 help
0983 Enable this to generate a spurious interrupt just before a shared
0984 interrupt handler is deregistered (generating one when registering
0985 is currently disabled). Drivers need to handle this correctly. Some
0986 don't and need to be caught.
0987
0988 menu "Debug Oops, Lockups and Hangs"
0989
0990 config PANIC_ON_OOPS
0991 bool "Panic on Oops"
0992 help
0993 Say Y here to enable the kernel to panic when it oopses. This
0994 has the same effect as setting oops=panic on the kernel command
0995 line.
0996
0997 This feature is useful to ensure that the kernel does not do
0998 anything erroneous after an oops which could result in data
0999 corruption or other issues.
1000
1001 Say N if unsure.
1002
1003 config PANIC_ON_OOPS_VALUE
1004 int
1005 range 0 1
1006 default 0 if !PANIC_ON_OOPS
1007 default 1 if PANIC_ON_OOPS
1008
1009 config PANIC_TIMEOUT
1010 int "panic timeout"
1011 default 0
1012 help
1013 Set the timeout value (in seconds) until a reboot occurs when
1014 the kernel panics. If n = 0, then we wait forever. A timeout
1015 value n > 0 will wait n seconds before rebooting, while a timeout
1016 value n < 0 will reboot immediately.
1017
1018 config LOCKUP_DETECTOR
1019 bool
1020
1021 config SOFTLOCKUP_DETECTOR
1022 bool "Detect Soft Lockups"
1023 depends on DEBUG_KERNEL && !S390
1024 select LOCKUP_DETECTOR
1025 help
1026 Say Y here to enable the kernel to act as a watchdog to detect
1027 soft lockups.
1028
1029 Softlockups are bugs that cause the kernel to loop in kernel
1030 mode for more than 20 seconds, without giving other tasks a
1031 chance to run. The current stack trace is displayed upon
1032 detection and the system will stay locked up.
1033
1034 config BOOTPARAM_SOFTLOCKUP_PANIC
1035 bool "Panic (Reboot) On Soft Lockups"
1036 depends on SOFTLOCKUP_DETECTOR
1037 help
1038 Say Y here to enable the kernel to panic on "soft lockups",
1039 which are bugs that cause the kernel to loop in kernel
1040 mode for more than 20 seconds (configurable using the watchdog_thresh
1041 sysctl), without giving other tasks a chance to run.
1042
1043 The panic can be used in combination with panic_timeout,
1044 to cause the system to reboot automatically after a
1045 lockup has been detected. This feature is useful for
1046 high-availability systems that have uptime guarantees and
1047 where a lockup must be resolved ASAP.
1048
1049 Say N if unsure.
1050
1051 config HARDLOCKUP_DETECTOR_PERF
1052 bool
1053 select SOFTLOCKUP_DETECTOR
1054
1055 #
1056 # Enables a timestamp based low pass filter to compensate for perf based
1057 # hard lockup detection which runs too fast due to turbo modes.
1058 #
1059 config HARDLOCKUP_CHECK_TIMESTAMP
1060 bool
1061
1062 #
1063 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1064 # lockup detector rather than the perf based detector.
1065 #
1066 config HARDLOCKUP_DETECTOR
1067 bool "Detect Hard Lockups"
1068 depends on DEBUG_KERNEL && !S390
1069 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1070 select LOCKUP_DETECTOR
1071 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
1072 help
1073 Say Y here to enable the kernel to act as a watchdog to detect
1074 hard lockups.
1075
1076 Hardlockups are bugs that cause the CPU to loop in kernel mode
1077 for more than 10 seconds, without letting other interrupts have a
1078 chance to run. The current stack trace is displayed upon detection
1079 and the system will stay locked up.
1080
1081 config BOOTPARAM_HARDLOCKUP_PANIC
1082 bool "Panic (Reboot) On Hard Lockups"
1083 depends on HARDLOCKUP_DETECTOR
1084 help
1085 Say Y here to enable the kernel to panic on "hard lockups",
1086 which are bugs that cause the kernel to loop in kernel
1087 mode with interrupts disabled for more than 10 seconds (configurable
1088 using the watchdog_thresh sysctl).
1089
1090 Say N if unsure.
1091
1092 config DETECT_HUNG_TASK
1093 bool "Detect Hung Tasks"
1094 depends on DEBUG_KERNEL
1095 default SOFTLOCKUP_DETECTOR
1096 help
1097 Say Y here to enable the kernel to detect "hung tasks",
1098 which are bugs that cause the task to be stuck in
1099 uninterruptible "D" state indefinitely.
1100
1101 When a hung task is detected, the kernel will print the
1102 current stack trace (which you should report), but the
1103 task will stay in uninterruptible state. If lockdep is
1104 enabled then all held locks will also be reported. This
1105 feature has negligible overhead.
1106
1107 config DEFAULT_HUNG_TASK_TIMEOUT
1108 int "Default timeout for hung task detection (in seconds)"
1109 depends on DETECT_HUNG_TASK
1110 default 120
1111 help
1112 This option controls the default timeout (in seconds) used
1113 to determine when a task has become non-responsive and should
1114 be considered hung.
1115
1116 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1117 sysctl or by writing a value to
1118 /proc/sys/kernel/hung_task_timeout_secs.
1119
1120 A timeout of 0 disables the check. The default is two minutes.
1121 Keeping the default should be fine in most cases.
1122
1123 config BOOTPARAM_HUNG_TASK_PANIC
1124 bool "Panic (Reboot) On Hung Tasks"
1125 depends on DETECT_HUNG_TASK
1126 help
1127 Say Y here to enable the kernel to panic on "hung tasks",
1128 which are bugs that cause the kernel to leave a task stuck
1129 in uninterruptible "D" state.
1130
1131 The panic can be used in combination with panic_timeout,
1132 to cause the system to reboot automatically after a
1133 hung task has been detected. This feature is useful for
1134 high-availability systems that have uptime guarantees and
1135 where a hung tasks must be resolved ASAP.
1136
1137 Say N if unsure.
1138
1139 config WQ_WATCHDOG
1140 bool "Detect Workqueue Stalls"
1141 depends on DEBUG_KERNEL
1142 help
1143 Say Y here to enable stall detection on workqueues. If a
1144 worker pool doesn't make forward progress on a pending work
1145 item for over a given amount of time, 30s by default, a
1146 warning message is printed along with dump of workqueue
1147 state. This can be configured through kernel parameter
1148 "workqueue.watchdog_thresh" and its sysfs counterpart.
1149
1150 config TEST_LOCKUP
1151 tristate "Test module to generate lockups"
1152 depends on m
1153 help
1154 This builds the "test_lockup" module that helps to make sure
1155 that watchdogs and lockup detectors are working properly.
1156
1157 Depending on module parameters it could emulate soft or hard
1158 lockup, "hung task", or locking arbitrary lock for a long time.
1159 Also it could generate series of lockups with cooling-down periods.
1160
1161 If unsure, say N.
1162
1163 endmenu # "Debug lockups and hangs"
1164
1165 menu "Scheduler Debugging"
1166
1167 config SCHED_DEBUG
1168 bool "Collect scheduler debugging info"
1169 depends on DEBUG_KERNEL && PROC_FS
1170 default y
1171 help
1172 If you say Y here, the /proc/sched_debug file will be provided
1173 that can help debug the scheduler. The runtime overhead of this
1174 option is minimal.
1175
1176 config SCHED_INFO
1177 bool
1178 default n
1179
1180 config SCHEDSTATS
1181 bool "Collect scheduler statistics"
1182 depends on DEBUG_KERNEL && PROC_FS
1183 select SCHED_INFO
1184 help
1185 If you say Y here, additional code will be inserted into the
1186 scheduler and related routines to collect statistics about
1187 scheduler behavior and provide them in /proc/schedstat. These
1188 stats may be useful for both tuning and debugging the scheduler
1189 If you aren't debugging the scheduler or trying to tune a specific
1190 application, you can say N to avoid the very slight overhead
1191 this adds.
1192
1193 endmenu
1194
1195 config DEBUG_TIMEKEEPING
1196 bool "Enable extra timekeeping sanity checking"
1197 help
1198 This option will enable additional timekeeping sanity checks
1199 which may be helpful when diagnosing issues where timekeeping
1200 problems are suspected.
1201
1202 This may include checks in the timekeeping hotpaths, so this
1203 option may have a (very small) performance impact to some
1204 workloads.
1205
1206 If unsure, say N.
1207
1208 config DEBUG_PREEMPT
1209 bool "Debug preemptible kernel"
1210 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1211 default y
1212 help
1213 If you say Y here then the kernel will use a debug variant of the
1214 commonly used smp_processor_id() function and will print warnings
1215 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1216 will detect preemption count underflows.
1217
1218 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1219
1220 config LOCK_DEBUGGING_SUPPORT
1221 bool
1222 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1223 default y
1224
1225 config PROVE_LOCKING
1226 bool "Lock debugging: prove locking correctness"
1227 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1228 select LOCKDEP
1229 select DEBUG_SPINLOCK
1230 select DEBUG_MUTEXES if !PREEMPT_RT
1231 select DEBUG_RT_MUTEXES if RT_MUTEXES
1232 select DEBUG_RWSEMS
1233 select DEBUG_WW_MUTEX_SLOWPATH
1234 select DEBUG_LOCK_ALLOC
1235 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
1236 select TRACE_IRQFLAGS
1237 default n
1238 help
1239 This feature enables the kernel to prove that all locking
1240 that occurs in the kernel runtime is mathematically
1241 correct: that under no circumstance could an arbitrary (and
1242 not yet triggered) combination of observed locking
1243 sequences (on an arbitrary number of CPUs, running an
1244 arbitrary number of tasks and interrupt contexts) cause a
1245 deadlock.
1246
1247 In short, this feature enables the kernel to report locking
1248 related deadlocks before they actually occur.
1249
1250 The proof does not depend on how hard and complex a
1251 deadlock scenario would be to trigger: how many
1252 participant CPUs, tasks and irq-contexts would be needed
1253 for it to trigger. The proof also does not depend on
1254 timing: if a race and a resulting deadlock is possible
1255 theoretically (no matter how unlikely the race scenario
1256 is), it will be proven so and will immediately be
1257 reported by the kernel (once the event is observed that
1258 makes the deadlock theoretically possible).
1259
1260 If a deadlock is impossible (i.e. the locking rules, as
1261 observed by the kernel, are mathematically correct), the
1262 kernel reports nothing.
1263
1264 NOTE: this feature can also be enabled for rwlocks, mutexes
1265 and rwsems - in which case all dependencies between these
1266 different locking variants are observed and mapped too, and
1267 the proof of observed correctness is also maintained for an
1268 arbitrary combination of these separate locking variants.
1269
1270 For more details, see Documentation/locking/lockdep-design.rst.
1271
1272 config PROVE_RAW_LOCK_NESTING
1273 bool "Enable raw_spinlock - spinlock nesting checks"
1274 depends on PROVE_LOCKING
1275 default n
1276 help
1277 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1278 that the lock nesting rules for PREEMPT_RT enabled kernels are
1279 not violated.
1280
1281 NOTE: There are known nesting problems. So if you enable this
1282 option expect lockdep splats until these problems have been fully
1283 addressed which is work in progress. This config switch allows to
1284 identify and analyze these problems. It will be removed and the
1285 check permanently enabled once the main issues have been fixed.
1286
1287 If unsure, select N.
1288
1289 config LOCK_STAT
1290 bool "Lock usage statistics"
1291 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1292 select LOCKDEP
1293 select DEBUG_SPINLOCK
1294 select DEBUG_MUTEXES if !PREEMPT_RT
1295 select DEBUG_RT_MUTEXES if RT_MUTEXES
1296 select DEBUG_LOCK_ALLOC
1297 default n
1298 help
1299 This feature enables tracking lock contention points
1300
1301 For more details, see Documentation/locking/lockstat.rst
1302
1303 This also enables lock events required by "perf lock",
1304 subcommand of perf.
1305 If you want to use "perf lock", you also need to turn on
1306 CONFIG_EVENT_TRACING.
1307
1308 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1309 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1310
1311 config DEBUG_RT_MUTEXES
1312 bool "RT Mutex debugging, deadlock detection"
1313 depends on DEBUG_KERNEL && RT_MUTEXES
1314 help
1315 This allows rt mutex semantics violations and rt mutex related
1316 deadlocks (lockups) to be detected and reported automatically.
1317
1318 config DEBUG_SPINLOCK
1319 bool "Spinlock and rw-lock debugging: basic checks"
1320 depends on DEBUG_KERNEL
1321 select UNINLINE_SPIN_UNLOCK
1322 help
1323 Say Y here and build SMP to catch missing spinlock initialization
1324 and certain other kinds of spinlock errors commonly made. This is
1325 best used in conjunction with the NMI watchdog so that spinlock
1326 deadlocks are also debuggable.
1327
1328 config DEBUG_MUTEXES
1329 bool "Mutex debugging: basic checks"
1330 depends on DEBUG_KERNEL && !PREEMPT_RT
1331 help
1332 This feature allows mutex semantics violations to be detected and
1333 reported.
1334
1335 config DEBUG_WW_MUTEX_SLOWPATH
1336 bool "Wait/wound mutex debugging: Slowpath testing"
1337 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1338 select DEBUG_LOCK_ALLOC
1339 select DEBUG_SPINLOCK
1340 select DEBUG_MUTEXES if !PREEMPT_RT
1341 select DEBUG_RT_MUTEXES if PREEMPT_RT
1342 help
1343 This feature enables slowpath testing for w/w mutex users by
1344 injecting additional -EDEADLK wound/backoff cases. Together with
1345 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1346 will test all possible w/w mutex interface abuse with the
1347 exception of simply not acquiring all the required locks.
1348 Note that this feature can introduce significant overhead, so
1349 it really should not be enabled in a production or distro kernel,
1350 even a debug kernel. If you are a driver writer, enable it. If
1351 you are a distro, do not.
1352
1353 config DEBUG_RWSEMS
1354 bool "RW Semaphore debugging: basic checks"
1355 depends on DEBUG_KERNEL
1356 help
1357 This debugging feature allows mismatched rw semaphore locks
1358 and unlocks to be detected and reported.
1359
1360 config DEBUG_LOCK_ALLOC
1361 bool "Lock debugging: detect incorrect freeing of live locks"
1362 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1363 select DEBUG_SPINLOCK
1364 select DEBUG_MUTEXES if !PREEMPT_RT
1365 select DEBUG_RT_MUTEXES if RT_MUTEXES
1366 select LOCKDEP
1367 help
1368 This feature will check whether any held lock (spinlock, rwlock,
1369 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1370 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1371 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1372 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1373 held during task exit.
1374
1375 config LOCKDEP
1376 bool
1377 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1378 select STACKTRACE
1379 select KALLSYMS
1380 select KALLSYMS_ALL
1381
1382 config LOCKDEP_SMALL
1383 bool
1384
1385 config LOCKDEP_BITS
1386 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1387 depends on LOCKDEP && !LOCKDEP_SMALL
1388 range 10 30
1389 default 15
1390 help
1391 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1392
1393 config LOCKDEP_CHAINS_BITS
1394 int "Bitsize for MAX_LOCKDEP_CHAINS"
1395 depends on LOCKDEP && !LOCKDEP_SMALL
1396 range 10 30
1397 default 16
1398 help
1399 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1400
1401 config LOCKDEP_STACK_TRACE_BITS
1402 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1403 depends on LOCKDEP && !LOCKDEP_SMALL
1404 range 10 30
1405 default 19
1406 help
1407 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1408
1409 config LOCKDEP_STACK_TRACE_HASH_BITS
1410 int "Bitsize for STACK_TRACE_HASH_SIZE"
1411 depends on LOCKDEP && !LOCKDEP_SMALL
1412 range 10 30
1413 default 14
1414 help
1415 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1416
1417 config LOCKDEP_CIRCULAR_QUEUE_BITS
1418 int "Bitsize for elements in circular_queue struct"
1419 depends on LOCKDEP
1420 range 10 30
1421 default 12
1422 help
1423 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1424
1425 config DEBUG_LOCKDEP
1426 bool "Lock dependency engine debugging"
1427 depends on DEBUG_KERNEL && LOCKDEP
1428 select DEBUG_IRQFLAGS
1429 help
1430 If you say Y here, the lock dependency engine will do
1431 additional runtime checks to debug itself, at the price
1432 of more runtime overhead.
1433
1434 config DEBUG_ATOMIC_SLEEP
1435 bool "Sleep inside atomic section checking"
1436 select PREEMPT_COUNT
1437 depends on DEBUG_KERNEL
1438 depends on !ARCH_NO_PREEMPT
1439 help
1440 If you say Y here, various routines which may sleep will become very
1441 noisy if they are called inside atomic sections: when a spinlock is
1442 held, inside an rcu read side critical section, inside preempt disabled
1443 sections, inside an interrupt, etc...
1444
1445 config DEBUG_LOCKING_API_SELFTESTS
1446 bool "Locking API boot-time self-tests"
1447 depends on DEBUG_KERNEL
1448 help
1449 Say Y here if you want the kernel to run a short self-test during
1450 bootup. The self-test checks whether common types of locking bugs
1451 are detected by debugging mechanisms or not. (if you disable
1452 lock debugging then those bugs won't be detected of course.)
1453 The following locking APIs are covered: spinlocks, rwlocks,
1454 mutexes and rwsems.
1455
1456 config LOCK_TORTURE_TEST
1457 tristate "torture tests for locking"
1458 depends on DEBUG_KERNEL
1459 select TORTURE_TEST
1460 help
1461 This option provides a kernel module that runs torture tests
1462 on kernel locking primitives. The kernel module may be built
1463 after the fact on the running kernel to be tested, if desired.
1464
1465 Say Y here if you want kernel locking-primitive torture tests
1466 to be built into the kernel.
1467 Say M if you want these torture tests to build as a module.
1468 Say N if you are unsure.
1469
1470 config WW_MUTEX_SELFTEST
1471 tristate "Wait/wound mutex selftests"
1472 help
1473 This option provides a kernel module that runs tests on the
1474 on the struct ww_mutex locking API.
1475
1476 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1477 with this test harness.
1478
1479 Say M if you want these self tests to build as a module.
1480 Say N if you are unsure.
1481
1482 config SCF_TORTURE_TEST
1483 tristate "torture tests for smp_call_function*()"
1484 depends on DEBUG_KERNEL
1485 select TORTURE_TEST
1486 help
1487 This option provides a kernel module that runs torture tests
1488 on the smp_call_function() family of primitives. The kernel
1489 module may be built after the fact on the running kernel to
1490 be tested, if desired.
1491
1492 config CSD_LOCK_WAIT_DEBUG
1493 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1494 depends on DEBUG_KERNEL
1495 depends on 64BIT
1496 default n
1497 help
1498 This option enables debug prints when CPUs are slow to respond
1499 to the smp_call_function*() IPI wrappers. These debug prints
1500 include the IPI handler function currently executing (if any)
1501 and relevant stack traces.
1502
1503 endmenu # lock debugging
1504
1505 config TRACE_IRQFLAGS
1506 depends on TRACE_IRQFLAGS_SUPPORT
1507 bool
1508 help
1509 Enables hooks to interrupt enabling and disabling for
1510 either tracing or lock debugging.
1511
1512 config TRACE_IRQFLAGS_NMI
1513 def_bool y
1514 depends on TRACE_IRQFLAGS
1515 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1516
1517 config DEBUG_IRQFLAGS
1518 bool "Debug IRQ flag manipulation"
1519 help
1520 Enables checks for potentially unsafe enabling or disabling of
1521 interrupts, such as calling raw_local_irq_restore() when interrupts
1522 are enabled.
1523
1524 config STACKTRACE
1525 bool "Stack backtrace support"
1526 depends on STACKTRACE_SUPPORT
1527 help
1528 This option causes the kernel to create a /proc/pid/stack for
1529 every process, showing its current stack trace.
1530 It is also used by various kernel debugging features that require
1531 stack trace generation.
1532
1533 config WARN_ALL_UNSEEDED_RANDOM
1534 bool "Warn for all uses of unseeded randomness"
1535 default n
1536 help
1537 Some parts of the kernel contain bugs relating to their use of
1538 cryptographically secure random numbers before it's actually possible
1539 to generate those numbers securely. This setting ensures that these
1540 flaws don't go unnoticed, by enabling a message, should this ever
1541 occur. This will allow people with obscure setups to know when things
1542 are going wrong, so that they might contact developers about fixing
1543 it.
1544
1545 Unfortunately, on some models of some architectures getting
1546 a fully seeded CRNG is extremely difficult, and so this can
1547 result in dmesg getting spammed for a surprisingly long
1548 time. This is really bad from a security perspective, and
1549 so architecture maintainers really need to do what they can
1550 to get the CRNG seeded sooner after the system is booted.
1551 However, since users cannot do anything actionable to
1552 address this, by default this option is disabled.
1553
1554 Say Y here if you want to receive warnings for all uses of
1555 unseeded randomness. This will be of use primarily for
1556 those developers interested in improving the security of
1557 Linux kernels running on their architecture (or
1558 subarchitecture).
1559
1560 config DEBUG_KOBJECT
1561 bool "kobject debugging"
1562 depends on DEBUG_KERNEL
1563 help
1564 If you say Y here, some extra kobject debugging messages will be sent
1565 to the syslog.
1566
1567 config DEBUG_KOBJECT_RELEASE
1568 bool "kobject release debugging"
1569 depends on DEBUG_OBJECTS_TIMERS
1570 help
1571 kobjects are reference counted objects. This means that their
1572 last reference count put is not predictable, and the kobject can
1573 live on past the point at which a driver decides to drop its
1574 initial reference to the kobject gained on allocation. An
1575 example of this would be a struct device which has just been
1576 unregistered.
1577
1578 However, some buggy drivers assume that after such an operation,
1579 the memory backing the kobject can be immediately freed. This
1580 goes completely against the principles of a refcounted object.
1581
1582 If you say Y here, the kernel will delay the release of kobjects
1583 on the last reference count to improve the visibility of this
1584 kind of kobject release bug.
1585
1586 config HAVE_DEBUG_BUGVERBOSE
1587 bool
1588
1589 menu "Debug kernel data structures"
1590
1591 config DEBUG_LIST
1592 bool "Debug linked list manipulation"
1593 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1594 help
1595 Enable this to turn on extended checks in the linked-list
1596 walking routines.
1597
1598 If unsure, say N.
1599
1600 config DEBUG_PLIST
1601 bool "Debug priority linked list manipulation"
1602 depends on DEBUG_KERNEL
1603 help
1604 Enable this to turn on extended checks in the priority-ordered
1605 linked-list (plist) walking routines. This checks the entire
1606 list multiple times during each manipulation.
1607
1608 If unsure, say N.
1609
1610 config DEBUG_SG
1611 bool "Debug SG table operations"
1612 depends on DEBUG_KERNEL
1613 help
1614 Enable this to turn on checks on scatter-gather tables. This can
1615 help find problems with drivers that do not properly initialize
1616 their sg tables.
1617
1618 If unsure, say N.
1619
1620 config DEBUG_NOTIFIERS
1621 bool "Debug notifier call chains"
1622 depends on DEBUG_KERNEL
1623 help
1624 Enable this to turn on sanity checking for notifier call chains.
1625 This is most useful for kernel developers to make sure that
1626 modules properly unregister themselves from notifier chains.
1627 This is a relatively cheap check but if you care about maximum
1628 performance, say N.
1629
1630 config BUG_ON_DATA_CORRUPTION
1631 bool "Trigger a BUG when data corruption is detected"
1632 select DEBUG_LIST
1633 help
1634 Select this option if the kernel should BUG when it encounters
1635 data corruption in kernel memory structures when they get checked
1636 for validity.
1637
1638 If unsure, say N.
1639
1640 endmenu
1641
1642 config DEBUG_CREDENTIALS
1643 bool "Debug credential management"
1644 depends on DEBUG_KERNEL
1645 help
1646 Enable this to turn on some debug checking for credential
1647 management. The additional code keeps track of the number of
1648 pointers from task_structs to any given cred struct, and checks to
1649 see that this number never exceeds the usage count of the cred
1650 struct.
1651
1652 Furthermore, if SELinux is enabled, this also checks that the
1653 security pointer in the cred struct is never seen to be invalid.
1654
1655 If unsure, say N.
1656
1657 source "kernel/rcu/Kconfig.debug"
1658
1659 config DEBUG_WQ_FORCE_RR_CPU
1660 bool "Force round-robin CPU selection for unbound work items"
1661 depends on DEBUG_KERNEL
1662 default n
1663 help
1664 Workqueue used to implicitly guarantee that work items queued
1665 without explicit CPU specified are put on the local CPU. This
1666 guarantee is no longer true and while local CPU is still
1667 preferred work items may be put on foreign CPUs. Kernel
1668 parameter "workqueue.debug_force_rr_cpu" is added to force
1669 round-robin CPU selection to flush out usages which depend on the
1670 now broken guarantee. This config option enables the debug
1671 feature by default. When enabled, memory and cache locality will
1672 be impacted.
1673
1674 config CPU_HOTPLUG_STATE_CONTROL
1675 bool "Enable CPU hotplug state control"
1676 depends on DEBUG_KERNEL
1677 depends on HOTPLUG_CPU
1678 default n
1679 help
1680 Allows to write steps between "offline" and "online" to the CPUs
1681 sysfs target file so states can be stepped granular. This is a debug
1682 option for now as the hotplug machinery cannot be stopped and
1683 restarted at arbitrary points yet.
1684
1685 Say N if your are unsure.
1686
1687 config LATENCYTOP
1688 bool "Latency measuring infrastructure"
1689 depends on DEBUG_KERNEL
1690 depends on STACKTRACE_SUPPORT
1691 depends on PROC_FS
1692 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1693 select KALLSYMS
1694 select KALLSYMS_ALL
1695 select STACKTRACE
1696 select SCHEDSTATS
1697 help
1698 Enable this option if you want to use the LatencyTOP tool
1699 to find out which userspace is blocking on what kernel operations.
1700
1701 source "kernel/trace/Kconfig"
1702
1703 config PROVIDE_OHCI1394_DMA_INIT
1704 bool "Remote debugging over FireWire early on boot"
1705 depends on PCI && X86
1706 help
1707 If you want to debug problems which hang or crash the kernel early
1708 on boot and the crashing machine has a FireWire port, you can use
1709 this feature to remotely access the memory of the crashed machine
1710 over FireWire. This employs remote DMA as part of the OHCI1394
1711 specification which is now the standard for FireWire controllers.
1712
1713 With remote DMA, you can monitor the printk buffer remotely using
1714 firescope and access all memory below 4GB using fireproxy from gdb.
1715 Even controlling a kernel debugger is possible using remote DMA.
1716
1717 Usage:
1718
1719 If ohci1394_dma=early is used as boot parameter, it will initialize
1720 all OHCI1394 controllers which are found in the PCI config space.
1721
1722 As all changes to the FireWire bus such as enabling and disabling
1723 devices cause a bus reset and thereby disable remote DMA for all
1724 devices, be sure to have the cable plugged and FireWire enabled on
1725 the debugging host before booting the debug target for debugging.
1726
1727 This code (~1k) is freed after boot. By then, the firewire stack
1728 in charge of the OHCI-1394 controllers should be used instead.
1729
1730 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
1731
1732 source "samples/Kconfig"
1733
1734 config ARCH_HAS_DEVMEM_IS_ALLOWED
1735 bool
1736
1737 config STRICT_DEVMEM
1738 bool "Filter access to /dev/mem"
1739 depends on MMU && DEVMEM
1740 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
1741 default y if PPC || X86 || ARM64
1742 help
1743 If this option is disabled, you allow userspace (root) access to all
1744 of memory, including kernel and userspace memory. Accidental
1745 access to this is obviously disastrous, but specific access can
1746 be used by people debugging the kernel. Note that with PAT support
1747 enabled, even in this case there are restrictions on /dev/mem
1748 use due to the cache aliasing requirements.
1749
1750 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1751 file only allows userspace access to PCI space and the BIOS code and
1752 data regions. This is sufficient for dosemu and X and all common
1753 users of /dev/mem.
1754
1755 If in doubt, say Y.
1756
1757 config IO_STRICT_DEVMEM
1758 bool "Filter I/O access to /dev/mem"
1759 depends on STRICT_DEVMEM
1760 help
1761 If this option is disabled, you allow userspace (root) access to all
1762 io-memory regardless of whether a driver is actively using that
1763 range. Accidental access to this is obviously disastrous, but
1764 specific access can be used by people debugging kernel drivers.
1765
1766 If this option is switched on, the /dev/mem file only allows
1767 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1768 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1769 if the driver using a given range cannot be disabled.
1770
1771 If in doubt, say Y.
1772
1773 menu "$(SRCARCH) Debugging"
1774
1775 source "arch/$(SRCARCH)/Kconfig.debug"
1776
1777 endmenu
1778
1779 menu "Kernel Testing and Coverage"
1780
1781 source "lib/kunit/Kconfig"
1782
1783 config NOTIFIER_ERROR_INJECTION
1784 tristate "Notifier error injection"
1785 depends on DEBUG_KERNEL
1786 select DEBUG_FS
1787 help
1788 This option provides the ability to inject artificial errors to
1789 specified notifier chain callbacks. It is useful to test the error
1790 handling of notifier call chain failures.
1791
1792 Say N if unsure.
1793
1794 config PM_NOTIFIER_ERROR_INJECT
1795 tristate "PM notifier error injection module"
1796 depends on PM && NOTIFIER_ERROR_INJECTION
1797 default m if PM_DEBUG
1798 help
1799 This option provides the ability to inject artificial errors to
1800 PM notifier chain callbacks. It is controlled through debugfs
1801 interface /sys/kernel/debug/notifier-error-inject/pm
1802
1803 If the notifier call chain should be failed with some events
1804 notified, write the error code to "actions/<notifier event>/error".
1805
1806 Example: Inject PM suspend error (-12 = -ENOMEM)
1807
1808 # cd /sys/kernel/debug/notifier-error-inject/pm/
1809 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1810 # echo mem > /sys/power/state
1811 bash: echo: write error: Cannot allocate memory
1812
1813 To compile this code as a module, choose M here: the module will
1814 be called pm-notifier-error-inject.
1815
1816 If unsure, say N.
1817
1818 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1819 tristate "OF reconfig notifier error injection module"
1820 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1821 help
1822 This option provides the ability to inject artificial errors to
1823 OF reconfig notifier chain callbacks. It is controlled
1824 through debugfs interface under
1825 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1826
1827 If the notifier call chain should be failed with some events
1828 notified, write the error code to "actions/<notifier event>/error".
1829
1830 To compile this code as a module, choose M here: the module will
1831 be called of-reconfig-notifier-error-inject.
1832
1833 If unsure, say N.
1834
1835 config NETDEV_NOTIFIER_ERROR_INJECT
1836 tristate "Netdev notifier error injection module"
1837 depends on NET && NOTIFIER_ERROR_INJECTION
1838 help
1839 This option provides the ability to inject artificial errors to
1840 netdevice notifier chain callbacks. It is controlled through debugfs
1841 interface /sys/kernel/debug/notifier-error-inject/netdev
1842
1843 If the notifier call chain should be failed with some events
1844 notified, write the error code to "actions/<notifier event>/error".
1845
1846 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1847
1848 # cd /sys/kernel/debug/notifier-error-inject/netdev
1849 # echo -22 > actions/NETDEV_CHANGEMTU/error
1850 # ip link set eth0 mtu 1024
1851 RTNETLINK answers: Invalid argument
1852
1853 To compile this code as a module, choose M here: the module will
1854 be called netdev-notifier-error-inject.
1855
1856 If unsure, say N.
1857
1858 config FUNCTION_ERROR_INJECTION
1859 def_bool y
1860 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1861
1862 config FAULT_INJECTION
1863 bool "Fault-injection framework"
1864 depends on DEBUG_KERNEL
1865 help
1866 Provide fault-injection framework.
1867 For more details, see Documentation/fault-injection/.
1868
1869 config FAILSLAB
1870 bool "Fault-injection capability for kmalloc"
1871 depends on FAULT_INJECTION
1872 depends on SLAB || SLUB
1873 help
1874 Provide fault-injection capability for kmalloc.
1875
1876 config FAIL_PAGE_ALLOC
1877 bool "Fault-injection capability for alloc_pages()"
1878 depends on FAULT_INJECTION
1879 help
1880 Provide fault-injection capability for alloc_pages().
1881
1882 config FAULT_INJECTION_USERCOPY
1883 bool "Fault injection capability for usercopy functions"
1884 depends on FAULT_INJECTION
1885 help
1886 Provides fault-injection capability to inject failures
1887 in usercopy functions (copy_from_user(), get_user(), ...).
1888
1889 config FAIL_MAKE_REQUEST
1890 bool "Fault-injection capability for disk IO"
1891 depends on FAULT_INJECTION && BLOCK
1892 help
1893 Provide fault-injection capability for disk IO.
1894
1895 config FAIL_IO_TIMEOUT
1896 bool "Fault-injection capability for faking disk interrupts"
1897 depends on FAULT_INJECTION && BLOCK
1898 help
1899 Provide fault-injection capability on end IO handling. This
1900 will make the block layer "forget" an interrupt as configured,
1901 thus exercising the error handling.
1902
1903 Only works with drivers that use the generic timeout handling,
1904 for others it won't do anything.
1905
1906 config FAIL_FUTEX
1907 bool "Fault-injection capability for futexes"
1908 select DEBUG_FS
1909 depends on FAULT_INJECTION && FUTEX
1910 help
1911 Provide fault-injection capability for futexes.
1912
1913 config FAULT_INJECTION_DEBUG_FS
1914 bool "Debugfs entries for fault-injection capabilities"
1915 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1916 help
1917 Enable configuration of fault-injection capabilities via debugfs.
1918
1919 config FAIL_FUNCTION
1920 bool "Fault-injection capability for functions"
1921 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1922 help
1923 Provide function-based fault-injection capability.
1924 This will allow you to override a specific function with a return
1925 with given return value. As a result, function caller will see
1926 an error value and have to handle it. This is useful to test the
1927 error handling in various subsystems.
1928
1929 config FAIL_MMC_REQUEST
1930 bool "Fault-injection capability for MMC IO"
1931 depends on FAULT_INJECTION_DEBUG_FS && MMC
1932 help
1933 Provide fault-injection capability for MMC IO.
1934 This will make the mmc core return data errors. This is
1935 useful to test the error handling in the mmc block device
1936 and to test how the mmc host driver handles retries from
1937 the block device.
1938
1939 config FAIL_SUNRPC
1940 bool "Fault-injection capability for SunRPC"
1941 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1942 help
1943 Provide fault-injection capability for SunRPC and
1944 its consumers.
1945
1946 config FAULT_INJECTION_STACKTRACE_FILTER
1947 bool "stacktrace filter for fault-injection capabilities"
1948 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1949 depends on !X86_64
1950 select STACKTRACE
1951 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1952 help
1953 Provide stacktrace filter for fault-injection capabilities
1954
1955 config ARCH_HAS_KCOV
1956 bool
1957 help
1958 An architecture should select this when it can successfully
1959 build and run with CONFIG_KCOV. This typically requires
1960 disabling instrumentation for some early boot code.
1961
1962 config CC_HAS_SANCOV_TRACE_PC
1963 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1964
1965
1966 config KCOV
1967 bool "Code coverage for fuzzing"
1968 depends on ARCH_HAS_KCOV
1969 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1970 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \
1971 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000
1972 select DEBUG_FS
1973 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1974 select OBJTOOL if HAVE_NOINSTR_HACK
1975 help
1976 KCOV exposes kernel code coverage information in a form suitable
1977 for coverage-guided fuzzing (randomized testing).
1978
1979 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1980 different machines and across reboots. If you need stable PC values,
1981 disable RANDOMIZE_BASE.
1982
1983 For more details, see Documentation/dev-tools/kcov.rst.
1984
1985 config KCOV_ENABLE_COMPARISONS
1986 bool "Enable comparison operands collection by KCOV"
1987 depends on KCOV
1988 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
1989 help
1990 KCOV also exposes operands of every comparison in the instrumented
1991 code along with operand sizes and PCs of the comparison instructions.
1992 These operands can be used by fuzzing engines to improve the quality
1993 of fuzzing coverage.
1994
1995 config KCOV_INSTRUMENT_ALL
1996 bool "Instrument all code by default"
1997 depends on KCOV
1998 default y
1999 help
2000 If you are doing generic system call fuzzing (like e.g. syzkaller),
2001 then you will want to instrument the whole kernel and you should
2002 say y here. If you are doing more targeted fuzzing (like e.g.
2003 filesystem fuzzing with AFL) then you will want to enable coverage
2004 for more specific subsets of files, and should say n here.
2005
2006 config KCOV_IRQ_AREA_SIZE
2007 hex "Size of interrupt coverage collection area in words"
2008 depends on KCOV
2009 default 0x40000
2010 help
2011 KCOV uses preallocated per-cpu areas to collect coverage from
2012 soft interrupts. This specifies the size of those areas in the
2013 number of unsigned long words.
2014
2015 menuconfig RUNTIME_TESTING_MENU
2016 bool "Runtime Testing"
2017 def_bool y
2018
2019 if RUNTIME_TESTING_MENU
2020
2021 config LKDTM
2022 tristate "Linux Kernel Dump Test Tool Module"
2023 depends on DEBUG_FS
2024 help
2025 This module enables testing of the different dumping mechanisms by
2026 inducing system failures at predefined crash points.
2027 If you don't need it: say N
2028 Choose M here to compile this code as a module. The module will be
2029 called lkdtm.
2030
2031 Documentation on how to use the module can be found in
2032 Documentation/fault-injection/provoke-crashes.rst
2033
2034 config CPUMASK_KUNIT_TEST
2035 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS
2036 depends on KUNIT
2037 default KUNIT_ALL_TESTS
2038 help
2039 Enable to turn on cpumask tests, running at boot or module load time.
2040
2041 For more information on KUnit and unit tests in general, please refer
2042 to the KUnit documentation in Documentation/dev-tools/kunit/.
2043
2044 If unsure, say N.
2045
2046 config TEST_LIST_SORT
2047 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2048 depends on KUNIT
2049 default KUNIT_ALL_TESTS
2050 help
2051 Enable this to turn on 'list_sort()' function test. This test is
2052 executed only once during system boot (so affects only boot time),
2053 or at module load time.
2054
2055 If unsure, say N.
2056
2057 config TEST_MIN_HEAP
2058 tristate "Min heap test"
2059 depends on DEBUG_KERNEL || m
2060 help
2061 Enable this to turn on min heap function tests. This test is
2062 executed only once during system boot (so affects only boot time),
2063 or at module load time.
2064
2065 If unsure, say N.
2066
2067 config TEST_SORT
2068 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2069 depends on KUNIT
2070 default KUNIT_ALL_TESTS
2071 help
2072 This option enables the self-test function of 'sort()' at boot,
2073 or at module load time.
2074
2075 If unsure, say N.
2076
2077 config TEST_DIV64
2078 tristate "64bit/32bit division and modulo test"
2079 depends on DEBUG_KERNEL || m
2080 help
2081 Enable this to turn on 'do_div()' function test. This test is
2082 executed only once during system boot (so affects only boot time),
2083 or at module load time.
2084
2085 If unsure, say N.
2086
2087 config KPROBES_SANITY_TEST
2088 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS
2089 depends on DEBUG_KERNEL
2090 depends on KPROBES
2091 depends on KUNIT
2092 default KUNIT_ALL_TESTS
2093 help
2094 This option provides for testing basic kprobes functionality on
2095 boot. Samples of kprobe and kretprobe are inserted and
2096 verified for functionality.
2097
2098 Say N if you are unsure.
2099
2100 config FPROBE_SANITY_TEST
2101 bool "Self test for fprobe"
2102 depends on DEBUG_KERNEL
2103 depends on FPROBE
2104 depends on KUNIT=y
2105 help
2106 This option will enable testing the fprobe when the system boot.
2107 A series of tests are made to verify that the fprobe is functioning
2108 properly.
2109
2110 Say N if you are unsure.
2111
2112 config BACKTRACE_SELF_TEST
2113 tristate "Self test for the backtrace code"
2114 depends on DEBUG_KERNEL
2115 help
2116 This option provides a kernel module that can be used to test
2117 the kernel stack backtrace code. This option is not useful
2118 for distributions or general kernels, but only for kernel
2119 developers working on architecture code.
2120
2121 Note that if you want to also test saved backtraces, you will
2122 have to enable STACKTRACE as well.
2123
2124 Say N if you are unsure.
2125
2126 config TEST_REF_TRACKER
2127 tristate "Self test for reference tracker"
2128 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
2129 select REF_TRACKER
2130 help
2131 This option provides a kernel module performing tests
2132 using reference tracker infrastructure.
2133
2134 Say N if you are unsure.
2135
2136 config RBTREE_TEST
2137 tristate "Red-Black tree test"
2138 depends on DEBUG_KERNEL
2139 help
2140 A benchmark measuring the performance of the rbtree library.
2141 Also includes rbtree invariant checks.
2142
2143 config REED_SOLOMON_TEST
2144 tristate "Reed-Solomon library test"
2145 depends on DEBUG_KERNEL || m
2146 select REED_SOLOMON
2147 select REED_SOLOMON_ENC16
2148 select REED_SOLOMON_DEC16
2149 help
2150 This option enables the self-test function of rslib at boot,
2151 or at module load time.
2152
2153 If unsure, say N.
2154
2155 config INTERVAL_TREE_TEST
2156 tristate "Interval tree test"
2157 depends on DEBUG_KERNEL
2158 select INTERVAL_TREE
2159 help
2160 A benchmark measuring the performance of the interval tree library
2161
2162 config PERCPU_TEST
2163 tristate "Per cpu operations test"
2164 depends on m && DEBUG_KERNEL
2165 help
2166 Enable this option to build test module which validates per-cpu
2167 operations.
2168
2169 If unsure, say N.
2170
2171 config ATOMIC64_SELFTEST
2172 tristate "Perform an atomic64_t self-test"
2173 help
2174 Enable this option to test the atomic64_t functions at boot or
2175 at module load time.
2176
2177 If unsure, say N.
2178
2179 config ASYNC_RAID6_TEST
2180 tristate "Self test for hardware accelerated raid6 recovery"
2181 depends on ASYNC_RAID6_RECOV
2182 select ASYNC_MEMCPY
2183 help
2184 This is a one-shot self test that permutes through the
2185 recovery of all the possible two disk failure scenarios for a
2186 N-disk array. Recovery is performed with the asynchronous
2187 raid6 recovery routines, and will optionally use an offload
2188 engine if one is available.
2189
2190 If unsure, say N.
2191
2192 config TEST_HEXDUMP
2193 tristate "Test functions located in the hexdump module at runtime"
2194
2195 config STRING_SELFTEST
2196 tristate "Test string functions at runtime"
2197
2198 config TEST_STRING_HELPERS
2199 tristate "Test functions located in the string_helpers module at runtime"
2200
2201 config TEST_STRSCPY
2202 tristate "Test strscpy*() family of functions at runtime"
2203
2204 config TEST_KSTRTOX
2205 tristate "Test kstrto*() family of functions at runtime"
2206
2207 config TEST_PRINTF
2208 tristate "Test printf() family of functions at runtime"
2209
2210 config TEST_SCANF
2211 tristate "Test scanf() family of functions at runtime"
2212
2213 config TEST_BITMAP
2214 tristate "Test bitmap_*() family of functions at runtime"
2215 help
2216 Enable this option to test the bitmap functions at boot.
2217
2218 If unsure, say N.
2219
2220 config TEST_UUID
2221 tristate "Test functions located in the uuid module at runtime"
2222
2223 config TEST_XARRAY
2224 tristate "Test the XArray code at runtime"
2225
2226 config TEST_RHASHTABLE
2227 tristate "Perform selftest on resizable hash table"
2228 help
2229 Enable this option to test the rhashtable functions at boot.
2230
2231 If unsure, say N.
2232
2233 config TEST_SIPHASH
2234 tristate "Perform selftest on siphash functions"
2235 help
2236 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash
2237 functions on boot (or module load).
2238
2239 This is intended to help people writing architecture-specific
2240 optimized versions. If unsure, say N.
2241
2242 config TEST_IDA
2243 tristate "Perform selftest on IDA functions"
2244
2245 config TEST_PARMAN
2246 tristate "Perform selftest on priority array manager"
2247 depends on PARMAN
2248 help
2249 Enable this option to test priority array manager on boot
2250 (or module load).
2251
2252 If unsure, say N.
2253
2254 config TEST_IRQ_TIMINGS
2255 bool "IRQ timings selftest"
2256 depends on IRQ_TIMINGS
2257 help
2258 Enable this option to test the irq timings code on boot.
2259
2260 If unsure, say N.
2261
2262 config TEST_LKM
2263 tristate "Test module loading with 'hello world' module"
2264 depends on m
2265 help
2266 This builds the "test_module" module that emits "Hello, world"
2267 on printk when loaded. It is designed to be used for basic
2268 evaluation of the module loading subsystem (for example when
2269 validating module verification). It lacks any extra dependencies,
2270 and will not normally be loaded by the system unless explicitly
2271 requested by name.
2272
2273 If unsure, say N.
2274
2275 config TEST_BITOPS
2276 tristate "Test module for compilation of bitops operations"
2277 depends on m
2278 help
2279 This builds the "test_bitops" module that is much like the
2280 TEST_LKM module except that it does a basic exercise of the
2281 set/clear_bit macros and get_count_order/long to make sure there are
2282 no compiler warnings from C=1 sparse checker or -Wextra
2283 compilations. It has no dependencies and doesn't run or load unless
2284 explicitly requested by name. for example: modprobe test_bitops.
2285
2286 If unsure, say N.
2287
2288 config TEST_VMALLOC
2289 tristate "Test module for stress/performance analysis of vmalloc allocator"
2290 default n
2291 depends on MMU
2292 depends on m
2293 help
2294 This builds the "test_vmalloc" module that should be used for
2295 stress and performance analysis. So, any new change for vmalloc
2296 subsystem can be evaluated from performance and stability point
2297 of view.
2298
2299 If unsure, say N.
2300
2301 config TEST_USER_COPY
2302 tristate "Test user/kernel boundary protections"
2303 depends on m
2304 help
2305 This builds the "test_user_copy" module that runs sanity checks
2306 on the copy_to/from_user infrastructure, making sure basic
2307 user/kernel boundary testing is working. If it fails to load,
2308 a regression has been detected in the user/kernel memory boundary
2309 protections.
2310
2311 If unsure, say N.
2312
2313 config TEST_BPF
2314 tristate "Test BPF filter functionality"
2315 depends on m && NET
2316 help
2317 This builds the "test_bpf" module that runs various test vectors
2318 against the BPF interpreter or BPF JIT compiler depending on the
2319 current setting. This is in particular useful for BPF JIT compiler
2320 development, but also to run regression tests against changes in
2321 the interpreter code. It also enables test stubs for eBPF maps and
2322 verifier used by user space verifier testsuite.
2323
2324 If unsure, say N.
2325
2326 config TEST_BLACKHOLE_DEV
2327 tristate "Test blackhole netdev functionality"
2328 depends on m && NET
2329 help
2330 This builds the "test_blackhole_dev" module that validates the
2331 data path through this blackhole netdev.
2332
2333 If unsure, say N.
2334
2335 config FIND_BIT_BENCHMARK
2336 tristate "Test find_bit functions"
2337 help
2338 This builds the "test_find_bit" module that measure find_*_bit()
2339 functions performance.
2340
2341 If unsure, say N.
2342
2343 config TEST_FIRMWARE
2344 tristate "Test firmware loading via userspace interface"
2345 depends on FW_LOADER
2346 help
2347 This builds the "test_firmware" module that creates a userspace
2348 interface for testing firmware loading. This can be used to
2349 control the triggering of firmware loading without needing an
2350 actual firmware-using device. The contents can be rechecked by
2351 userspace.
2352
2353 If unsure, say N.
2354
2355 config TEST_SYSCTL
2356 tristate "sysctl test driver"
2357 depends on PROC_SYSCTL
2358 help
2359 This builds the "test_sysctl" module. This driver enables to test the
2360 proc sysctl interfaces available to drivers safely without affecting
2361 production knobs which might alter system functionality.
2362
2363 If unsure, say N.
2364
2365 config BITFIELD_KUNIT
2366 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS
2367 depends on KUNIT
2368 default KUNIT_ALL_TESTS
2369 help
2370 Enable this option to test the bitfield functions at boot.
2371
2372 KUnit tests run during boot and output the results to the debug log
2373 in TAP format (http://testanything.org/). Only useful for kernel devs
2374 running the KUnit test harness, and not intended for inclusion into a
2375 production build.
2376
2377 For more information on KUnit and unit tests in general please refer
2378 to the KUnit documentation in Documentation/dev-tools/kunit/.
2379
2380 If unsure, say N.
2381
2382 config HASH_KUNIT_TEST
2383 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS
2384 depends on KUNIT
2385 default KUNIT_ALL_TESTS
2386 help
2387 Enable this option to test the kernel's string (<linux/stringhash.h>), and
2388 integer (<linux/hash.h>) hash functions on boot.
2389
2390 KUnit tests run during boot and output the results to the debug log
2391 in TAP format (https://testanything.org/). Only useful for kernel devs
2392 running the KUnit test harness, and not intended for inclusion into a
2393 production build.
2394
2395 For more information on KUnit and unit tests in general please refer
2396 to the KUnit documentation in Documentation/dev-tools/kunit/.
2397
2398 This is intended to help people writing architecture-specific
2399 optimized versions. If unsure, say N.
2400
2401 config RESOURCE_KUNIT_TEST
2402 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
2403 depends on KUNIT
2404 default KUNIT_ALL_TESTS
2405 help
2406 This builds the resource API unit test.
2407 Tests the logic of API provided by resource.c and ioport.h.
2408 For more information on KUnit and unit tests in general please refer
2409 to the KUnit documentation in Documentation/dev-tools/kunit/.
2410
2411 If unsure, say N.
2412
2413 config SYSCTL_KUNIT_TEST
2414 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2415 depends on KUNIT
2416 default KUNIT_ALL_TESTS
2417 help
2418 This builds the proc sysctl unit test, which runs on boot.
2419 Tests the API contract and implementation correctness of sysctl.
2420 For more information on KUnit and unit tests in general please refer
2421 to the KUnit documentation in Documentation/dev-tools/kunit/.
2422
2423 If unsure, say N.
2424
2425 config LIST_KUNIT_TEST
2426 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
2427 depends on KUNIT
2428 default KUNIT_ALL_TESTS
2429 help
2430 This builds the linked list KUnit test suite.
2431 It tests that the API and basic functionality of the list_head type
2432 and associated macros.
2433
2434 KUnit tests run during boot and output the results to the debug log
2435 in TAP format (https://testanything.org/). Only useful for kernel devs
2436 running the KUnit test harness, and not intended for inclusion into a
2437 production build.
2438
2439 For more information on KUnit and unit tests in general please refer
2440 to the KUnit documentation in Documentation/dev-tools/kunit/.
2441
2442 If unsure, say N.
2443
2444 config LINEAR_RANGES_TEST
2445 tristate "KUnit test for linear_ranges"
2446 depends on KUNIT
2447 select LINEAR_RANGES
2448 help
2449 This builds the linear_ranges unit test, which runs on boot.
2450 Tests the linear_ranges logic correctness.
2451 For more information on KUnit and unit tests in general please refer
2452 to the KUnit documentation in Documentation/dev-tools/kunit/.
2453
2454 If unsure, say N.
2455
2456 config CMDLINE_KUNIT_TEST
2457 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS
2458 depends on KUNIT
2459 default KUNIT_ALL_TESTS
2460 help
2461 This builds the cmdline API unit test.
2462 Tests the logic of API provided by cmdline.c.
2463 For more information on KUnit and unit tests in general please refer
2464 to the KUnit documentation in Documentation/dev-tools/kunit/.
2465
2466 If unsure, say N.
2467
2468 config BITS_TEST
2469 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS
2470 depends on KUNIT
2471 default KUNIT_ALL_TESTS
2472 help
2473 This builds the bits unit test.
2474 Tests the logic of macros defined in bits.h.
2475 For more information on KUnit and unit tests in general please refer
2476 to the KUnit documentation in Documentation/dev-tools/kunit/.
2477
2478 If unsure, say N.
2479
2480 config SLUB_KUNIT_TEST
2481 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2482 depends on SLUB_DEBUG && KUNIT
2483 default KUNIT_ALL_TESTS
2484 help
2485 This builds SLUB allocator unit test.
2486 Tests SLUB cache debugging functionality.
2487 For more information on KUnit and unit tests in general please refer
2488 to the KUnit documentation in Documentation/dev-tools/kunit/.
2489
2490 If unsure, say N.
2491
2492 config RATIONAL_KUNIT_TEST
2493 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
2494 depends on KUNIT && RATIONAL
2495 default KUNIT_ALL_TESTS
2496 help
2497 This builds the rational math unit test.
2498 For more information on KUnit and unit tests in general please refer
2499 to the KUnit documentation in Documentation/dev-tools/kunit/.
2500
2501 If unsure, say N.
2502
2503 config MEMCPY_KUNIT_TEST
2504 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
2505 depends on KUNIT
2506 default KUNIT_ALL_TESTS
2507 help
2508 Builds unit tests for memcpy(), memmove(), and memset() functions.
2509 For more information on KUnit and unit tests in general please refer
2510 to the KUnit documentation in Documentation/dev-tools/kunit/.
2511
2512 If unsure, say N.
2513
2514 config OVERFLOW_KUNIT_TEST
2515 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS
2516 depends on KUNIT
2517 default KUNIT_ALL_TESTS
2518 help
2519 Builds unit tests for the check_*_overflow(), size_*(), allocation, and
2520 related functions.
2521
2522 For more information on KUnit and unit tests in general please refer
2523 to the KUnit documentation in Documentation/dev-tools/kunit/.
2524
2525 If unsure, say N.
2526
2527 config STACKINIT_KUNIT_TEST
2528 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS
2529 depends on KUNIT
2530 default KUNIT_ALL_TESTS
2531 help
2532 Test if the kernel is zero-initializing stack variables and
2533 padding. Coverage is controlled by compiler flags,
2534 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO,
2535 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2536 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2537
2538 config TEST_UDELAY
2539 tristate "udelay test driver"
2540 help
2541 This builds the "udelay_test" module that helps to make sure
2542 that udelay() is working properly.
2543
2544 If unsure, say N.
2545
2546 config TEST_STATIC_KEYS
2547 tristate "Test static keys"
2548 depends on m
2549 help
2550 Test the static key interfaces.
2551
2552 If unsure, say N.
2553
2554 config TEST_KMOD
2555 tristate "kmod stress tester"
2556 depends on m
2557 depends on NETDEVICES && NET_CORE && INET # for TUN
2558 depends on BLOCK
2559 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS
2560 select TEST_LKM
2561 select XFS_FS
2562 select TUN
2563 select BTRFS_FS
2564 help
2565 Test the kernel's module loading mechanism: kmod. kmod implements
2566 support to load modules using the Linux kernel's usermode helper.
2567 This test provides a series of tests against kmod.
2568
2569 Although technically you can either build test_kmod as a module or
2570 into the kernel we disallow building it into the kernel since
2571 it stress tests request_module() and this will very likely cause
2572 some issues by taking over precious threads available from other
2573 module load requests, ultimately this could be fatal.
2574
2575 To run tests run:
2576
2577 tools/testing/selftests/kmod/kmod.sh --help
2578
2579 If unsure, say N.
2580
2581 config TEST_DEBUG_VIRTUAL
2582 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2583 depends on DEBUG_VIRTUAL
2584 help
2585 Test the kernel's ability to detect incorrect calls to
2586 virt_to_phys() done against the non-linear part of the
2587 kernel's virtual address map.
2588
2589 If unsure, say N.
2590
2591 config TEST_MEMCAT_P
2592 tristate "Test memcat_p() helper function"
2593 help
2594 Test the memcat_p() helper for correctly merging two
2595 pointer arrays together.
2596
2597 If unsure, say N.
2598
2599 config TEST_LIVEPATCH
2600 tristate "Test livepatching"
2601 default n
2602 depends on DYNAMIC_DEBUG
2603 depends on LIVEPATCH
2604 depends on m
2605 help
2606 Test kernel livepatching features for correctness. The tests will
2607 load test modules that will be livepatched in various scenarios.
2608
2609 To run all the livepatching tests:
2610
2611 make -C tools/testing/selftests TARGETS=livepatch run_tests
2612
2613 Alternatively, individual tests may be invoked:
2614
2615 tools/testing/selftests/livepatch/test-callbacks.sh
2616 tools/testing/selftests/livepatch/test-livepatch.sh
2617 tools/testing/selftests/livepatch/test-shadow-vars.sh
2618
2619 If unsure, say N.
2620
2621 config TEST_OBJAGG
2622 tristate "Perform selftest on object aggreration manager"
2623 default n
2624 depends on OBJAGG
2625 help
2626 Enable this option to test object aggregation manager on boot
2627 (or module load).
2628
2629 config TEST_MEMINIT
2630 tristate "Test heap/page initialization"
2631 help
2632 Test if the kernel is zero-initializing heap and page allocations.
2633 This can be useful to test init_on_alloc and init_on_free features.
2634
2635 If unsure, say N.
2636
2637 config TEST_HMM
2638 tristate "Test HMM (Heterogeneous Memory Management)"
2639 depends on TRANSPARENT_HUGEPAGE
2640 depends on DEVICE_PRIVATE
2641 select HMM_MIRROR
2642 select MMU_NOTIFIER
2643 help
2644 This is a pseudo device driver solely for testing HMM.
2645 Say M here if you want to build the HMM test module.
2646 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2647
2648 If unsure, say N.
2649
2650 config TEST_FREE_PAGES
2651 tristate "Test freeing pages"
2652 help
2653 Test that a memory leak does not occur due to a race between
2654 freeing a block of pages and a speculative page reference.
2655 Loading this module is safe if your kernel has the bug fixed.
2656 If the bug is not fixed, it will leak gigabytes of memory and
2657 probably OOM your system.
2658
2659 config TEST_FPU
2660 tristate "Test floating point operations in kernel space"
2661 depends on X86 && !KCOV_INSTRUMENT_ALL
2662 help
2663 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2664 which will trigger a sequence of floating point operations. This is used
2665 for self-testing floating point control register setting in
2666 kernel_fpu_begin().
2667
2668 If unsure, say N.
2669
2670 config TEST_CLOCKSOURCE_WATCHDOG
2671 tristate "Test clocksource watchdog in kernel space"
2672 depends on CLOCKSOURCE_WATCHDOG
2673 help
2674 Enable this option to create a kernel module that will trigger
2675 a test of the clocksource watchdog. This module may be loaded
2676 via modprobe or insmod in which case it will run upon being
2677 loaded, or it may be built in, in which case it will run
2678 shortly after boot.
2679
2680 If unsure, say N.
2681
2682 endif # RUNTIME_TESTING_MENU
2683
2684 config ARCH_USE_MEMTEST
2685 bool
2686 help
2687 An architecture should select this when it uses early_memtest()
2688 during boot process.
2689
2690 config MEMTEST
2691 bool "Memtest"
2692 depends on ARCH_USE_MEMTEST
2693 help
2694 This option adds a kernel parameter 'memtest', which allows memtest
2695 to be set and executed.
2696 memtest=0, mean disabled; -- default
2697 memtest=1, mean do 1 test pattern;
2698 ...
2699 memtest=17, mean do 17 test patterns.
2700 If you are unsure how to answer this question, answer N.
2701
2702
2703
2704 config HYPERV_TESTING
2705 bool "Microsoft Hyper-V driver testing"
2706 default n
2707 depends on HYPERV && DEBUG_FS
2708 help
2709 Select this option to enable Hyper-V vmbus testing.
2710
2711 endmenu # "Kernel Testing and Coverage"
2712
2713 source "Documentation/Kconfig"
2714
2715 endmenu # Kernel hacking
