|  | # SPDX-License-Identifier: GPL-2.0-only | 
|  | menu "Kernel hacking" | 
|  |  | 
|  | menu "printk and dmesg options" | 
|  |  | 
|  | config PRINTK_TIME | 
|  | bool "Show timing information on printks" | 
|  | depends on PRINTK | 
|  | help | 
|  | Selecting this option causes time stamps of the printk() | 
|  | messages to be added to the output of the syslog() system | 
|  | call and at the console. | 
|  |  | 
|  | The timestamp is always recorded internally, and exported | 
|  | to /dev/kmsg. This flag just specifies if the timestamp should | 
|  | be included, not that the timestamp is recorded. | 
|  |  | 
|  | The behavior is also controlled by the kernel command line | 
|  | parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst | 
|  |  | 
|  | config PRINTK_CALLER | 
|  | bool "Show caller information on printks" | 
|  | depends on PRINTK | 
|  | help | 
|  | Selecting this option causes printk() to add a caller "thread id" (if | 
|  | in task context) or a caller "processor id" (if not in task context) | 
|  | to every message. | 
|  |  | 
|  | This option is intended for environments where multiple threads | 
|  | concurrently call printk() for many times, for it is difficult to | 
|  | interpret without knowing where these lines (or sometimes individual | 
|  | line which was divided into multiple lines due to race) came from. | 
|  |  | 
|  | Since toggling after boot makes the code racy, currently there is | 
|  | no option to enable/disable at the kernel command line parameter or | 
|  | sysfs interface. | 
|  |  | 
|  | config STACKTRACE_BUILD_ID | 
|  | bool "Show build ID information in stacktraces" | 
|  | depends on PRINTK | 
|  | help | 
|  | Selecting this option adds build ID information for symbols in | 
|  | stacktraces printed with the printk format '%p[SR]b'. | 
|  |  | 
|  | This option is intended for distros where debuginfo is not easily | 
|  | accessible but can be downloaded given the build ID of the vmlinux or | 
|  | kernel module where the function is located. | 
|  |  | 
|  | config CONSOLE_LOGLEVEL_DEFAULT | 
|  | int "Default console loglevel (1-15)" | 
|  | range 1 15 | 
|  | default "7" | 
|  | help | 
|  | Default loglevel to determine what will be printed on the console. | 
|  |  | 
|  | Setting a default here is equivalent to passing in loglevel=<x> in | 
|  | the kernel bootargs. loglevel=<x> continues to override whatever | 
|  | value is specified here as well. | 
|  |  | 
|  | Note: This does not affect the log level of un-prefixed printk() | 
|  | usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT | 
|  | option. | 
|  |  | 
|  | config CONSOLE_LOGLEVEL_QUIET | 
|  | int "quiet console loglevel (1-15)" | 
|  | range 1 15 | 
|  | default "4" | 
|  | help | 
|  | loglevel to use when "quiet" is passed on the kernel commandline. | 
|  |  | 
|  | When "quiet" is passed on the kernel commandline this loglevel | 
|  | will be used as the loglevel. IOW passing "quiet" will be the | 
|  | equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>" | 
|  |  | 
|  | config MESSAGE_LOGLEVEL_DEFAULT | 
|  | int "Default message log level (1-7)" | 
|  | range 1 7 | 
|  | default "4" | 
|  | help | 
|  | Default log level for printk statements with no specified priority. | 
|  |  | 
|  | This was hard-coded to KERN_WARNING since at least 2.6.10 but folks | 
|  | that are auditing their logs closely may want to set it to a lower | 
|  | priority. | 
|  |  | 
|  | Note: This does not affect what message level gets printed on the console | 
|  | by default. To change that, use loglevel=<x> in the kernel bootargs, | 
|  | or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value. | 
|  |  | 
|  | config BOOT_PRINTK_DELAY | 
|  | bool "Delay each boot printk message by N milliseconds" | 
|  | depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY | 
|  | help | 
|  | This build option allows you to read kernel boot messages | 
|  | by inserting a short delay after each one.  The delay is | 
|  | specified in milliseconds on the kernel command line, | 
|  | using "boot_delay=N". | 
|  |  | 
|  | It is likely that you would also need to use "lpj=M" to preset | 
|  | the "loops per jiffy" value. | 
|  | See a previous boot log for the "lpj" value to use for your | 
|  | system, and then set "lpj=M" before setting "boot_delay=N". | 
|  | NOTE:  Using this option may adversely affect SMP systems. | 
|  | I.e., processors other than the first one may not boot up. | 
|  | BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect | 
|  | what it believes to be lockup conditions. | 
|  |  | 
|  | config DYNAMIC_DEBUG | 
|  | bool "Enable dynamic printk() support" | 
|  | default n | 
|  | depends on PRINTK | 
|  | depends on (DEBUG_FS || PROC_FS) | 
|  | select DYNAMIC_DEBUG_CORE | 
|  | help | 
|  |  | 
|  | Compiles debug level messages into the kernel, which would not | 
|  | otherwise be available at runtime. These messages can then be | 
|  | enabled/disabled based on various levels of scope - per source file, | 
|  | function, module, format string, and line number. This mechanism | 
|  | implicitly compiles in all pr_debug() and dev_dbg() calls, which | 
|  | enlarges the kernel text size by about 2%. | 
|  |  | 
|  | If a source file is compiled with DEBUG flag set, any | 
|  | pr_debug() calls in it are enabled by default, but can be | 
|  | disabled at runtime as below.  Note that DEBUG flag is | 
|  | turned on by many CONFIG_*DEBUG* options. | 
|  |  | 
|  | Usage: | 
|  |  | 
|  | Dynamic debugging is controlled via the 'dynamic_debug/control' file, | 
|  | which is contained in the 'debugfs' filesystem or procfs. | 
|  | Thus, the debugfs or procfs filesystem must first be mounted before | 
|  | making use of this feature. | 
|  | We refer the control file as: <debugfs>/dynamic_debug/control. This | 
|  | file contains a list of the debug statements that can be enabled. The | 
|  | format for each line of the file is: | 
|  |  | 
|  | filename:lineno [module]function flags format | 
|  |  | 
|  | filename : source file of the debug statement | 
|  | lineno : line number of the debug statement | 
|  | module : module that contains the debug statement | 
|  | function : function that contains the debug statement | 
|  | flags : '=p' means the line is turned 'on' for printing | 
|  | format : the format used for the debug statement | 
|  |  | 
|  | From a live system: | 
|  |  | 
|  | nullarbor:~ # cat <debugfs>/dynamic_debug/control | 
|  | # filename:lineno [module]function flags format | 
|  | fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012" | 
|  | fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012" | 
|  | fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012" | 
|  |  | 
|  | Example usage: | 
|  |  | 
|  | // enable the message at line 1603 of file svcsock.c | 
|  | nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' > | 
|  | <debugfs>/dynamic_debug/control | 
|  |  | 
|  | // enable all the messages in file svcsock.c | 
|  | nullarbor:~ # echo -n 'file svcsock.c +p' > | 
|  | <debugfs>/dynamic_debug/control | 
|  |  | 
|  | // enable all the messages in the NFS server module | 
|  | nullarbor:~ # echo -n 'module nfsd +p' > | 
|  | <debugfs>/dynamic_debug/control | 
|  |  | 
|  | // enable all 12 messages in the function svc_process() | 
|  | nullarbor:~ # echo -n 'func svc_process +p' > | 
|  | <debugfs>/dynamic_debug/control | 
|  |  | 
|  | // disable all 12 messages in the function svc_process() | 
|  | nullarbor:~ # echo -n 'func svc_process -p' > | 
|  | <debugfs>/dynamic_debug/control | 
|  |  | 
|  | See Documentation/admin-guide/dynamic-debug-howto.rst for additional | 
|  | information. | 
|  |  | 
|  | config DYNAMIC_DEBUG_CORE | 
|  | bool "Enable core function of dynamic debug support" | 
|  | depends on PRINTK | 
|  | depends on (DEBUG_FS || PROC_FS) | 
|  | help | 
|  | Enable core functional support of dynamic debug. It is useful | 
|  | when you want to tie dynamic debug to your kernel modules with | 
|  | DYNAMIC_DEBUG_MODULE defined for each of them, especially for | 
|  | the case of embedded system where the kernel image size is | 
|  | sensitive for people. | 
|  |  | 
|  | config SYMBOLIC_ERRNAME | 
|  | bool "Support symbolic error names in printf" | 
|  | default y if PRINTK | 
|  | help | 
|  | If you say Y here, the kernel's printf implementation will | 
|  | be able to print symbolic error names such as ENOSPC instead | 
|  | of the number 28. It makes the kernel image slightly larger | 
|  | (about 3KB), but can make the kernel logs easier to read. | 
|  |  | 
|  | config DEBUG_BUGVERBOSE | 
|  | bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT | 
|  | depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE) | 
|  | default y | 
|  | help | 
|  | Say Y here to make BUG() panics output the file name and line number | 
|  | of the BUG call as well as the EIP and oops trace.  This aids | 
|  | debugging but costs about 70-100K of memory. | 
|  |  | 
|  | endmenu # "printk and dmesg options" | 
|  |  | 
|  | config DEBUG_KERNEL | 
|  | bool "Kernel debugging" | 
|  | help | 
|  | Say Y here if you are developing drivers or trying to debug and | 
|  | identify kernel problems. | 
|  |  | 
|  | config DEBUG_MISC | 
|  | bool "Miscellaneous debug code" | 
|  | default DEBUG_KERNEL | 
|  | depends on DEBUG_KERNEL | 
|  | help | 
|  | Say Y here if you need to enable miscellaneous debug code that should | 
|  | be under a more specific debug option but isn't. | 
|  |  | 
|  | menu "Compile-time checks and compiler options" | 
|  |  | 
|  | config DEBUG_INFO | 
|  | bool | 
|  | help | 
|  | A kernel debug info option other than "None" has been selected | 
|  | in the "Debug information" choice below, indicating that debug | 
|  | information will be generated for build targets. | 
|  |  | 
|  | # Clang generates .uleb128 with label differences for DWARF v5, a feature that | 
|  | # older binutils ports do not support when utilizing RISC-V style linker | 
|  | # relaxation: https://sourceware.org/bugzilla/show_bug.cgi?id=27215 | 
|  | config AS_HAS_NON_CONST_ULEB128 | 
|  | def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:) | 
|  |  | 
|  | choice | 
|  | prompt "Debug information" | 
|  | depends on DEBUG_KERNEL | 
|  | help | 
|  | Selecting something other than "None" results in a kernel image | 
|  | that will include debugging info resulting in a larger kernel image. | 
|  | This adds debug symbols to the kernel and modules (gcc -g), and | 
|  | is needed if you intend to use kernel crashdump or binary object | 
|  | tools like crash, kgdb, LKCD, gdb, etc on the kernel. | 
|  |  | 
|  | Choose which version of DWARF debug info to emit. If unsure, | 
|  | select "Toolchain default". | 
|  |  | 
|  | config DEBUG_INFO_NONE | 
|  | bool "Disable debug information" | 
|  | help | 
|  | Do not build the kernel with debugging information, which will | 
|  | result in a faster and smaller build. | 
|  |  | 
|  | config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT | 
|  | bool "Rely on the toolchain's implicit default DWARF version" | 
|  | select DEBUG_INFO | 
|  | depends on !CC_IS_CLANG || AS_IS_LLVM || CLANG_VERSION < 140000 || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128) | 
|  | help | 
|  | The implicit default version of DWARF debug info produced by a | 
|  | toolchain changes over time. | 
|  |  | 
|  | This can break consumers of the debug info that haven't upgraded to | 
|  | support newer revisions, and prevent testing newer versions, but | 
|  | those should be less common scenarios. | 
|  |  | 
|  | config DEBUG_INFO_DWARF4 | 
|  | bool "Generate DWARF Version 4 debuginfo" | 
|  | select DEBUG_INFO | 
|  | depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502) | 
|  | help | 
|  | Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2 | 
|  | if using clang without clang's integrated assembler, and gdb 7.0+. | 
|  |  | 
|  | If you have consumers of DWARF debug info that are not ready for | 
|  | newer revisions of DWARF, you may wish to choose this or have your | 
|  | config select this. | 
|  |  | 
|  | config DEBUG_INFO_DWARF5 | 
|  | bool "Generate DWARF Version 5 debuginfo" | 
|  | select DEBUG_INFO | 
|  | depends on !ARCH_HAS_BROKEN_DWARF5 | 
|  | depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128) | 
|  | help | 
|  | Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc | 
|  | 5.0+ accepts the -gdwarf-5 flag but only had partial support for some | 
|  | draft features until 7.0), and gdb 8.0+. | 
|  |  | 
|  | Changes to the structure of debug info in Version 5 allow for around | 
|  | 15-18% savings in resulting image and debug info section sizes as | 
|  | compared to DWARF Version 4. DWARF Version 5 standardizes previous | 
|  | extensions such as accelerators for symbol indexing and the format | 
|  | for fission (.dwo/.dwp) files. Users may not want to select this | 
|  | config if they rely on tooling that has not yet been updated to | 
|  | support DWARF Version 5. | 
|  |  | 
|  | endchoice # "Debug information" | 
|  |  | 
|  | if DEBUG_INFO | 
|  |  | 
|  | config DEBUG_INFO_REDUCED | 
|  | bool "Reduce debugging information" | 
|  | help | 
|  | If you say Y here gcc is instructed to generate less debugging | 
|  | information for structure types. This means that tools that | 
|  | need full debugging information (like kgdb or systemtap) won't | 
|  | be happy. But if you merely need debugging information to | 
|  | resolve line numbers there is no loss. Advantage is that | 
|  | build directory object sizes shrink dramatically over a full | 
|  | DEBUG_INFO build and compile times are reduced too. | 
|  | Only works with newer gcc versions. | 
|  |  | 
|  | choice | 
|  | prompt "Compressed Debug information" | 
|  | help | 
|  | Compress the resulting debug info. Results in smaller debug info sections, | 
|  | but requires that consumers are able to decompress the results. | 
|  |  | 
|  | If unsure, choose DEBUG_INFO_COMPRESSED_NONE. | 
|  |  | 
|  | config DEBUG_INFO_COMPRESSED_NONE | 
|  | bool "Don't compress debug information" | 
|  | help | 
|  | Don't compress debug info sections. | 
|  |  | 
|  | config DEBUG_INFO_COMPRESSED_ZLIB | 
|  | bool "Compress debugging information with zlib" | 
|  | depends on $(cc-option,-gz=zlib) | 
|  | depends on $(ld-option,--compress-debug-sections=zlib) | 
|  | help | 
|  | Compress the debug information using zlib.  Requires GCC 5.0+ or Clang | 
|  | 5.0+, binutils 2.26+, and zlib. | 
|  |  | 
|  | Users of dpkg-deb via debian/rules may find an increase in | 
|  | size of their debug .deb packages with this config set, due to the | 
|  | debug info being compressed with zlib, then the object files being | 
|  | recompressed with a different compression scheme. But this is still | 
|  | preferable to setting KDEB_COMPRESS or DPKG_DEB_COMPRESSOR_TYPE to | 
|  | "none" which would be even larger. | 
|  |  | 
|  | config DEBUG_INFO_COMPRESSED_ZSTD | 
|  | bool "Compress debugging information with zstd" | 
|  | depends on $(cc-option,-gz=zstd) | 
|  | depends on $(ld-option,--compress-debug-sections=zstd) | 
|  | help | 
|  | Compress the debug information using zstd.  This may provide better | 
|  | compression than zlib, for about the same time costs, but requires newer | 
|  | toolchain support.  Requires GCC 13.0+ or Clang 16.0+, binutils 2.40+, and | 
|  | zstd. | 
|  |  | 
|  | endchoice # "Compressed Debug information" | 
|  |  | 
|  | config DEBUG_INFO_SPLIT | 
|  | bool "Produce split debuginfo in .dwo files" | 
|  | depends on $(cc-option,-gsplit-dwarf) | 
|  | # RISC-V linker relaxation + -gsplit-dwarf has issues with LLVM and GCC | 
|  | # prior to 12.x: | 
|  | # https://github.com/llvm/llvm-project/issues/56642 | 
|  | # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99090 | 
|  | depends on !RISCV || GCC_VERSION >= 120000 | 
|  | help | 
|  | Generate debug info into separate .dwo files. This significantly | 
|  | reduces the build directory size for builds with DEBUG_INFO, | 
|  | because it stores the information only once on disk in .dwo | 
|  | files instead of multiple times in object files and executables. | 
|  | In addition the debug information is also compressed. | 
|  |  | 
|  | Requires recent gcc (4.7+) and recent gdb/binutils. | 
|  | Any tool that packages or reads debug information would need | 
|  | to know about the .dwo files and include them. | 
|  | Incompatible with older versions of ccache. | 
|  |  | 
|  | config DEBUG_INFO_BTF | 
|  | bool "Generate BTF type information" | 
|  | depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED | 
|  | depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST | 
|  | depends on BPF_SYSCALL | 
|  | depends on PAHOLE_VERSION >= 116 | 
|  | depends on DEBUG_INFO_DWARF4 || PAHOLE_VERSION >= 121 | 
|  | # pahole uses elfutils, which does not have support for Hexagon relocations | 
|  | depends on !HEXAGON | 
|  | help | 
|  | Generate deduplicated BTF type information from DWARF debug info. | 
|  | Turning this on requires pahole v1.16 or later (v1.21 or later to | 
|  | support DWARF 5), which will convert DWARF type info into equivalent | 
|  | deduplicated BTF type info. | 
|  |  | 
|  | config PAHOLE_HAS_SPLIT_BTF | 
|  | def_bool PAHOLE_VERSION >= 119 | 
|  |  | 
|  | config PAHOLE_HAS_BTF_TAG | 
|  | def_bool PAHOLE_VERSION >= 123 | 
|  | depends on CC_IS_CLANG | 
|  | help | 
|  | Decide whether pahole emits btf_tag attributes (btf_type_tag and | 
|  | btf_decl_tag) or not. Currently only clang compiler implements | 
|  | these attributes, so make the config depend on CC_IS_CLANG. | 
|  |  | 
|  | config PAHOLE_HAS_LANG_EXCLUDE | 
|  | def_bool PAHOLE_VERSION >= 124 | 
|  | help | 
|  | Support for the --lang_exclude flag which makes pahole exclude | 
|  | compilation units from the supplied language. Used in Kbuild to | 
|  | omit Rust CUs which are not supported in version 1.24 of pahole, | 
|  | otherwise it would emit malformed kernel and module binaries when | 
|  | using DEBUG_INFO_BTF_MODULES. | 
|  |  | 
|  | config DEBUG_INFO_BTF_MODULES | 
|  | bool "Generate BTF type information for kernel modules" | 
|  | default y | 
|  | depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF | 
|  | help | 
|  | Generate compact split BTF type information for kernel modules. | 
|  |  | 
|  | config MODULE_ALLOW_BTF_MISMATCH | 
|  | bool "Allow loading modules with non-matching BTF type info" | 
|  | depends on DEBUG_INFO_BTF_MODULES | 
|  | help | 
|  | For modules whose split BTF does not match vmlinux, load without | 
|  | BTF rather than refusing to load. The default behavior with | 
|  | module BTF enabled is to reject modules with such mismatches; | 
|  | this option will still load module BTF where possible but ignore | 
|  | it when a mismatch is found. | 
|  |  | 
|  | config GDB_SCRIPTS | 
|  | bool "Provide GDB scripts for kernel debugging" | 
|  | help | 
|  | This creates the required links to GDB helper scripts in the | 
|  | build directory. If you load vmlinux into gdb, the helper | 
|  | scripts will be automatically imported by gdb as well, and | 
|  | additional functions are available to analyze a Linux kernel | 
|  | instance. See Documentation/process/debugging/gdb-kernel-debugging.rst | 
|  | for further details. | 
|  |  | 
|  | endif # DEBUG_INFO | 
|  |  | 
|  | config FRAME_WARN | 
|  | int "Warn for stack frames larger than" | 
|  | range 0 8192 | 
|  | default 0 if KMSAN | 
|  | default 2048 if GCC_PLUGIN_LATENT_ENTROPY | 
|  | default 2048 if PARISC | 
|  | default 1536 if (!64BIT && XTENSA) | 
|  | default 1280 if KASAN && !64BIT | 
|  | default 1024 if !64BIT | 
|  | default 2048 if 64BIT | 
|  | help | 
|  | Tell the compiler to warn at build time for stack frames larger than this. | 
|  | Setting this too low will cause a lot of warnings. | 
|  | Setting it to 0 disables the warning. | 
|  |  | 
|  | config STRIP_ASM_SYMS | 
|  | bool "Strip assembler-generated symbols during link" | 
|  | default n | 
|  | help | 
|  | Strip internal assembler-generated symbols during a link (symbols | 
|  | that look like '.Lxxx') so they don't pollute the output of | 
|  | get_wchan() and suchlike. | 
|  |  | 
|  | config READABLE_ASM | 
|  | bool "Generate readable assembler code" | 
|  | depends on DEBUG_KERNEL | 
|  | depends on CC_IS_GCC | 
|  | help | 
|  | Disable some compiler optimizations that tend to generate human unreadable | 
|  | assembler output. This may make the kernel slightly slower, but it helps | 
|  | to keep kernel developers who have to stare a lot at assembler listings | 
|  | sane. | 
|  |  | 
|  | config HEADERS_INSTALL | 
|  | bool "Install uapi headers to usr/include" | 
|  | help | 
|  | This option will install uapi headers (headers exported to user-space) | 
|  | into the usr/include directory for use during the kernel build. | 
|  | This is unneeded for building the kernel itself, but needed for some | 
|  | user-space program samples. It is also needed by some features such | 
|  | as uapi header sanity checks. | 
|  |  | 
|  | config DEBUG_SECTION_MISMATCH | 
|  | bool "Enable full Section mismatch analysis" | 
|  | depends on CC_IS_GCC | 
|  | help | 
|  | The section mismatch analysis checks if there are illegal | 
|  | references from one section to another section. | 
|  | During linktime or runtime, some sections are dropped; | 
|  | any use of code/data previously in these sections would | 
|  | most likely result in an oops. | 
|  | In the code, functions and variables are annotated with | 
|  | __init,, etc. (see the full list in include/linux/init.h), | 
|  | which results in the code/data being placed in specific sections. | 
|  | The section mismatch analysis is always performed after a full | 
|  | kernel build, and enabling this option causes the following | 
|  | additional step to occur: | 
|  | - Add the option -fno-inline-functions-called-once to gcc commands. | 
|  | When inlining a function annotated with __init in a non-init | 
|  | function, we would lose the section information and thus | 
|  | the analysis would not catch the illegal reference. | 
|  | This option tells gcc to inline less (but it does result in | 
|  | a larger kernel). | 
|  |  | 
|  | config SECTION_MISMATCH_WARN_ONLY | 
|  | bool "Make section mismatch errors non-fatal" | 
|  | default y | 
|  | help | 
|  | If you say N here, the build process will fail if there are any | 
|  | section mismatch, instead of just throwing warnings. | 
|  |  | 
|  | If unsure, say Y. | 
|  |  | 
|  | config DEBUG_FORCE_FUNCTION_ALIGN_64B | 
|  | bool "Force all function address 64B aligned" | 
|  | depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC || RISCV || S390) | 
|  | select FUNCTION_ALIGNMENT_64B | 
|  | help | 
|  | There are cases that a commit from one domain changes the function | 
|  | address alignment of other domains, and cause magic performance | 
|  | bump (regression or improvement). Enable this option will help to | 
|  | verify if the bump is caused by function alignment changes, while | 
|  | it will slightly increase the kernel size and affect icache usage. | 
|  |  | 
|  | It is mainly for debug and performance tuning use. | 
|  |  | 
|  | # | 
|  | # Select this config option from the architecture Kconfig, if it | 
|  | # is preferred to always offer frame pointers as a config | 
|  | # option on the architecture (regardless of KERNEL_DEBUG): | 
|  | # | 
|  | config ARCH_WANT_FRAME_POINTERS | 
|  | bool | 
|  |  | 
|  | config FRAME_POINTER | 
|  | bool "Compile the kernel with frame pointers" | 
|  | depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS | 
|  | default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS | 
|  | help | 
|  | If you say Y here the resulting kernel image will be slightly | 
|  | larger and slower, but it gives very useful debugging information | 
|  | in case of kernel bugs. (precise oopses/stacktraces/warnings) | 
|  |  | 
|  | config OBJTOOL | 
|  | bool | 
|  |  | 
|  | config OBJTOOL_WERROR | 
|  | bool "Upgrade objtool warnings to errors" | 
|  | depends on OBJTOOL && !COMPILE_TEST | 
|  | help | 
|  | Fail the build on objtool warnings. | 
|  |  | 
|  | Objtool warnings can indicate kernel instability, including boot | 
|  | failures.  This option is highly recommended. | 
|  |  | 
|  | If unsure, say Y. | 
|  |  | 
|  | config STACK_VALIDATION | 
|  | bool "Compile-time stack metadata validation" | 
|  | depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER | 
|  | select OBJTOOL | 
|  | default n | 
|  | help | 
|  | Validate frame pointer rules at compile-time.  This helps ensure that | 
|  | runtime stack traces are more reliable. | 
|  |  | 
|  | For more information, see | 
|  | tools/objtool/Documentation/objtool.txt. | 
|  |  | 
|  | config NOINSTR_VALIDATION | 
|  | bool | 
|  | depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY | 
|  | select OBJTOOL | 
|  | default y | 
|  |  | 
|  | config VMLINUX_MAP | 
|  | bool "Generate vmlinux.map file when linking" | 
|  | depends on EXPERT | 
|  | help | 
|  | Selecting this option will pass "-Map=vmlinux.map" to ld | 
|  | when linking vmlinux. That file can be useful for verifying | 
|  | and debugging magic section games, and for seeing which | 
|  | pieces of code get eliminated with | 
|  | CONFIG_LD_DEAD_CODE_DATA_ELIMINATION. | 
|  |  | 
|  | config BUILTIN_MODULE_RANGES | 
|  | bool "Generate address range information for builtin modules" | 
|  | depends on !LTO | 
|  | depends on VMLINUX_MAP | 
|  | help | 
|  | When modules are built into the kernel, there will be no module name | 
|  | associated with its symbols in /proc/kallsyms.  Tracers may want to | 
|  | identify symbols by module name and symbol name regardless of whether | 
|  | the module is configured as loadable or not. | 
|  |  | 
|  | This option generates modules.builtin.ranges in the build tree with | 
|  | offset ranges (per ELF section) for the module(s) they belong to. | 
|  | It also records an anchor symbol to determine the load address of the | 
|  | section. | 
|  |  | 
|  | config DEBUG_FORCE_WEAK_PER_CPU | 
|  | bool "Force weak per-cpu definitions" | 
|  | depends on DEBUG_KERNEL | 
|  | help | 
|  | s390 and alpha require percpu variables in modules to be | 
|  | defined weak to work around addressing range issue which | 
|  | puts the following two restrictions on percpu variable | 
|  | definitions. | 
|  |  | 
|  | 1. percpu symbols must be unique whether static or not | 
|  | 2. percpu variables can't be defined inside a function | 
|  |  | 
|  | To ensure that generic code follows the above rules, this | 
|  | option forces all percpu variables to be defined as weak. | 
|  |  | 
|  | endmenu # "Compiler options" | 
|  |  | 
|  | menu "Generic Kernel Debugging Instruments" | 
|  |  | 
|  | config MAGIC_SYSRQ | 
|  | bool "Magic SysRq key" | 
|  | depends on !UML | 
|  | help | 
|  | If you say Y here, you will have some control over the system even | 
|  | if the system crashes for example during kernel debugging (e.g., you | 
|  | will be able to flush the buffer cache to disk, reboot the system | 
|  | immediately or dump some status information). This is accomplished | 
|  | by pressing various keys while holding SysRq (Alt+PrintScreen). It | 
|  | also works on a serial console (on PC hardware at least), if you | 
|  | send a BREAK and then within 5 seconds a command keypress. The | 
|  | keys are documented in <file:Documentation/admin-guide/sysrq.rst>. | 
|  | Don't say Y unless you really know what this hack does. | 
|  |  | 
|  | config MAGIC_SYSRQ_DEFAULT_ENABLE | 
|  | hex "Enable magic SysRq key functions by default" | 
|  | depends on MAGIC_SYSRQ | 
|  | default 0x1 | 
|  | help | 
|  | Specifies which SysRq key functions are enabled by default. | 
|  | This may be set to 1 or 0 to enable or disable them all, or | 
|  | to a bitmask as described in Documentation/admin-guide/sysrq.rst. | 
|  |  | 
|  | config MAGIC_SYSRQ_SERIAL | 
|  | bool "Enable magic SysRq key over serial" | 
|  | depends on MAGIC_SYSRQ | 
|  | default y | 
|  | help | 
|  | Many embedded boards have a disconnected TTL level serial which can | 
|  | generate some garbage that can lead to spurious false sysrq detects. | 
|  | This option allows you to decide whether you want to enable the | 
|  | magic SysRq key. | 
|  |  | 
|  | config MAGIC_SYSRQ_SERIAL_SEQUENCE | 
|  | string "Char sequence that enables magic SysRq over serial" | 
|  | depends on MAGIC_SYSRQ_SERIAL | 
|  | default "" | 
|  | help | 
|  | Specifies a sequence of characters that can follow BREAK to enable | 
|  | SysRq on a serial console. | 
|  |  | 
|  | If unsure, leave an empty string and the option will not be enabled. | 
|  |  | 
|  | config DEBUG_FS | 
|  | bool "Debug Filesystem" | 
|  | help | 
|  | debugfs is a virtual file system that kernel developers use to put | 
|  | debugging files into.  Enable this option to be able to read and | 
|  | write to these files. | 
|  |  | 
|  | For detailed documentation on the debugfs API, see | 
|  | Documentation/filesystems/. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | choice | 
|  | prompt "Debugfs default access" | 
|  | depends on DEBUG_FS | 
|  | default DEBUG_FS_ALLOW_ALL | 
|  | help | 
|  | This selects the default access restrictions for debugfs. | 
|  | It can be overridden with kernel command line option | 
|  | debugfs=[on,no-mount,off]. The restrictions apply for API access | 
|  | and filesystem registration. | 
|  |  | 
|  | config DEBUG_FS_ALLOW_ALL | 
|  | bool "Access normal" | 
|  | help | 
|  | No restrictions apply. Both API and filesystem registration | 
|  | is on. This is the normal default operation. | 
|  |  | 
|  | config DEBUG_FS_DISALLOW_MOUNT | 
|  | bool "Do not register debugfs as filesystem" | 
|  | help | 
|  | The API is open but filesystem is not loaded. Clients can still do | 
|  | their work and read with debug tools that do not need | 
|  | debugfs filesystem. | 
|  |  | 
|  | config DEBUG_FS_ALLOW_NONE | 
|  | bool "No access" | 
|  | help | 
|  | Access is off. Clients get -PERM when trying to create nodes in | 
|  | debugfs tree and debugfs is not registered as a filesystem. | 
|  | Client can then back-off or continue without debugfs access. | 
|  |  | 
|  | endchoice | 
|  |  | 
|  | source "lib/Kconfig.kgdb" | 
|  | source "lib/Kconfig.ubsan" | 
|  | source "lib/Kconfig.kcsan" | 
|  |  | 
|  | endmenu | 
|  |  | 
|  | menu "Networking Debugging" | 
|  |  | 
|  | source "net/Kconfig.debug" | 
|  |  | 
|  | endmenu # "Networking Debugging" | 
|  |  | 
|  | menu "Memory Debugging" | 
|  |  | 
|  | source "mm/Kconfig.debug" | 
|  |  | 
|  | config DEBUG_OBJECTS | 
|  | bool "Debug object operations" | 
|  | depends on DEBUG_KERNEL | 
|  | help | 
|  | If you say Y here, additional code will be inserted into the | 
|  | kernel to track the life time of various objects and validate | 
|  | the operations on those objects. | 
|  |  | 
|  | config DEBUG_OBJECTS_SELFTEST | 
|  | bool "Debug objects selftest" | 
|  | depends on DEBUG_OBJECTS | 
|  | help | 
|  | This enables the selftest of the object debug code. | 
|  |  | 
|  | config DEBUG_OBJECTS_FREE | 
|  | bool "Debug objects in freed memory" | 
|  | depends on DEBUG_OBJECTS | 
|  | help | 
|  | This enables checks whether a k/v free operation frees an area | 
|  | which contains an object which has not been deactivated | 
|  | properly. This can make kmalloc/kfree-intensive workloads | 
|  | much slower. | 
|  |  | 
|  | config DEBUG_OBJECTS_TIMERS | 
|  | bool "Debug timer objects" | 
|  | depends on DEBUG_OBJECTS | 
|  | help | 
|  | If you say Y here, additional code will be inserted into the | 
|  | timer routines to track the life time of timer objects and | 
|  | validate the timer operations. | 
|  |  | 
|  | config DEBUG_OBJECTS_WORK | 
|  | bool "Debug work objects" | 
|  | depends on DEBUG_OBJECTS | 
|  | help | 
|  | If you say Y here, additional code will be inserted into the | 
|  | work queue routines to track the life time of work objects and | 
|  | validate the work operations. | 
|  |  | 
|  | config DEBUG_OBJECTS_RCU_HEAD | 
|  | bool "Debug RCU callbacks objects" | 
|  | depends on DEBUG_OBJECTS | 
|  | help | 
|  | Enable this to turn on debugging of RCU list heads (call_rcu() usage). | 
|  |  | 
|  | config DEBUG_OBJECTS_PERCPU_COUNTER | 
|  | bool "Debug percpu counter objects" | 
|  | depends on DEBUG_OBJECTS | 
|  | help | 
|  | If you say Y here, additional code will be inserted into the | 
|  | percpu counter routines to track the life time of percpu counter | 
|  | objects and validate the percpu counter operations. | 
|  |  | 
|  | config DEBUG_OBJECTS_ENABLE_DEFAULT | 
|  | int "debug_objects bootup default value (0-1)" | 
|  | range 0 1 | 
|  | default "1" | 
|  | depends on DEBUG_OBJECTS | 
|  | help | 
|  | Debug objects boot parameter default value | 
|  |  | 
|  | config SHRINKER_DEBUG | 
|  | bool "Enable shrinker debugging support" | 
|  | depends on DEBUG_FS | 
|  | help | 
|  | Say Y to enable the shrinker debugfs interface which provides | 
|  | visibility into the kernel memory shrinkers subsystem. | 
|  | Disable it to avoid an extra memory footprint. | 
|  |  | 
|  | config DEBUG_STACK_USAGE | 
|  | bool "Stack utilization instrumentation" | 
|  | depends on DEBUG_KERNEL | 
|  | help | 
|  | Enables the display of the minimum amount of free stack which each | 
|  | task has ever had available in the sysrq-T and sysrq-P debug output. | 
|  | Also emits a message to dmesg when a process exits if that process | 
|  | used more stack space than previously exiting processes. | 
|  |  | 
|  | This option will slow down process creation somewhat. | 
|  |  | 
|  | config SCHED_STACK_END_CHECK | 
|  | bool "Detect stack corruption on calls to schedule()" | 
|  | depends on DEBUG_KERNEL | 
|  | default n | 
|  | help | 
|  | This option checks for a stack overrun on calls to schedule(). | 
|  | If the stack end location is found to be over written always panic as | 
|  | the content of the corrupted region can no longer be trusted. | 
|  | This is to ensure no erroneous behaviour occurs which could result in | 
|  | data corruption or a sporadic crash at a later stage once the region | 
|  | is examined. The runtime overhead introduced is minimal. | 
|  |  | 
|  | config ARCH_HAS_DEBUG_VM_PGTABLE | 
|  | bool | 
|  | help | 
|  | An architecture should select this when it can successfully | 
|  | build and run DEBUG_VM_PGTABLE. | 
|  |  | 
|  | config DEBUG_VFS | 
|  | bool "Debug VFS" | 
|  | depends on DEBUG_KERNEL | 
|  | help | 
|  | Enable this to turn on extended checks in the VFS layer that may impact | 
|  | performance. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config DEBUG_VM_IRQSOFF | 
|  | def_bool DEBUG_VM && !PREEMPT_RT | 
|  |  | 
|  | config DEBUG_VM | 
|  | bool "Debug VM" | 
|  | depends on DEBUG_KERNEL | 
|  | help | 
|  | Enable this to turn on extended checks in the virtual-memory system | 
|  | that may impact performance. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config DEBUG_VM_SHOOT_LAZIES | 
|  | bool "Debug MMU_LAZY_TLB_SHOOTDOWN implementation" | 
|  | depends on DEBUG_VM | 
|  | depends on MMU_LAZY_TLB_SHOOTDOWN | 
|  | help | 
|  | Enable additional IPIs that ensure lazy tlb mm references are removed | 
|  | before the mm is freed. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config DEBUG_VM_MAPLE_TREE | 
|  | bool "Debug VM maple trees" | 
|  | depends on DEBUG_VM | 
|  | select DEBUG_MAPLE_TREE | 
|  | help | 
|  | Enable VM maple tree debugging information and extra validations. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config DEBUG_VM_RB | 
|  | bool "Debug VM red-black trees" | 
|  | depends on DEBUG_VM | 
|  | help | 
|  | Enable VM red-black tree debugging information and extra validations. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config DEBUG_VM_PGFLAGS | 
|  | bool "Debug page-flags operations" | 
|  | depends on DEBUG_VM | 
|  | help | 
|  | Enables extra validation on page flags operations. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config DEBUG_VM_PGTABLE | 
|  | bool "Debug arch page table for semantics compliance" | 
|  | depends on MMU | 
|  | depends on ARCH_HAS_DEBUG_VM_PGTABLE | 
|  | default y if DEBUG_VM | 
|  | help | 
|  | This option provides a debug method which can be used to test | 
|  | architecture page table helper functions on various platforms in | 
|  | verifying if they comply with expected generic MM semantics. This | 
|  | will help architecture code in making sure that any changes or | 
|  | new additions of these helpers still conform to expected | 
|  | semantics of the generic MM. Platforms will have to opt in for | 
|  | this through ARCH_HAS_DEBUG_VM_PGTABLE. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config ARCH_HAS_DEBUG_VIRTUAL | 
|  | bool | 
|  |  | 
|  | config DEBUG_VIRTUAL | 
|  | bool "Debug VM translations" | 
|  | depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL | 
|  | help | 
|  | Enable some costly sanity checks in virtual to page code. This can | 
|  | catch mistakes with virt_to_page() and friends. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config DEBUG_NOMMU_REGIONS | 
|  | bool "Debug the global anon/private NOMMU mapping region tree" | 
|  | depends on DEBUG_KERNEL && !MMU | 
|  | help | 
|  | This option causes the global tree of anonymous and private mapping | 
|  | regions to be regularly checked for invalid topology. | 
|  |  | 
|  | config DEBUG_MEMORY_INIT | 
|  | bool "Debug memory initialisation" if EXPERT | 
|  | default !EXPERT | 
|  | help | 
|  | Enable this for additional checks during memory initialisation. | 
|  | The sanity checks verify aspects of the VM such as the memory model | 
|  | and other information provided by the architecture. Verbose | 
|  | information will be printed at KERN_DEBUG loglevel depending | 
|  | on the mminit_loglevel= command-line option. | 
|  |  | 
|  | If unsure, say Y | 
|  |  | 
|  | config MEMORY_NOTIFIER_ERROR_INJECT | 
|  | tristate "Memory hotplug notifier error injection module" | 
|  | depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION | 
|  | help | 
|  | This option provides the ability to inject artificial errors to | 
|  | memory hotplug notifier chain callbacks.  It is controlled through | 
|  | debugfs interface under /sys/kernel/debug/notifier-error-inject/memory | 
|  |  | 
|  | If the notifier call chain should be failed with some events | 
|  | notified, write the error code to "actions/<notifier event>/error". | 
|  |  | 
|  | Example: Inject memory hotplug offline error (-12 == -ENOMEM) | 
|  |  | 
|  | # cd /sys/kernel/debug/notifier-error-inject/memory | 
|  | # echo -12 > actions/MEM_GOING_OFFLINE/error | 
|  | # echo offline > /sys/devices/system/memory/memoryXXX/state | 
|  | bash: echo: write error: Cannot allocate memory | 
|  |  | 
|  | To compile this code as a module, choose M here: the module will | 
|  | be called memory-notifier-error-inject. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config DEBUG_PER_CPU_MAPS | 
|  | bool "Debug access to per_cpu maps" | 
|  | depends on DEBUG_KERNEL | 
|  | depends on SMP | 
|  | help | 
|  | Say Y to verify that the per_cpu map being accessed has | 
|  | been set up. This adds a fair amount of code to kernel memory | 
|  | and decreases performance. | 
|  |  | 
|  | Say N if unsure. | 
|  |  | 
|  | config DEBUG_KMAP_LOCAL | 
|  | bool "Debug kmap_local temporary mappings" | 
|  | depends on DEBUG_KERNEL && KMAP_LOCAL | 
|  | help | 
|  | This option enables additional error checking for the kmap_local | 
|  | infrastructure.  Disable for production use. | 
|  |  | 
|  | config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP | 
|  | bool | 
|  |  | 
|  | config DEBUG_KMAP_LOCAL_FORCE_MAP | 
|  | bool "Enforce kmap_local temporary mappings" | 
|  | depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP | 
|  | select KMAP_LOCAL | 
|  | select DEBUG_KMAP_LOCAL | 
|  | help | 
|  | This option enforces temporary mappings through the kmap_local | 
|  | mechanism for non-highmem pages and on non-highmem systems. | 
|  | Disable this for production systems! | 
|  |  | 
|  | config DEBUG_HIGHMEM | 
|  | bool "Highmem debugging" | 
|  | depends on DEBUG_KERNEL && HIGHMEM | 
|  | select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP | 
|  | select DEBUG_KMAP_LOCAL | 
|  | help | 
|  | This option enables additional error checking for high memory | 
|  | systems.  Disable for production systems. | 
|  |  | 
|  | config HAVE_DEBUG_STACKOVERFLOW | 
|  | bool | 
|  |  | 
|  | config DEBUG_STACKOVERFLOW | 
|  | bool "Check for stack overflows" | 
|  | depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW | 
|  | help | 
|  | Say Y here if you want to check for overflows of kernel, IRQ | 
|  | and exception stacks (if your architecture uses them). This | 
|  | option will show detailed messages if free stack space drops | 
|  | below a certain limit. | 
|  |  | 
|  | These kinds of bugs usually occur when call-chains in the | 
|  | kernel get too deep, especially when interrupts are | 
|  | involved. | 
|  |  | 
|  | Use this in cases where you see apparently random memory | 
|  | corruption, especially if it appears in 'struct thread_info' | 
|  |  | 
|  | If in doubt, say "N". | 
|  |  | 
|  | config CODE_TAGGING | 
|  | bool | 
|  | select KALLSYMS | 
|  |  | 
|  | config MEM_ALLOC_PROFILING | 
|  | bool "Enable memory allocation profiling" | 
|  | default n | 
|  | depends on MMU | 
|  | depends on PROC_FS | 
|  | depends on !DEBUG_FORCE_WEAK_PER_CPU | 
|  | select CODE_TAGGING | 
|  | select PAGE_EXTENSION | 
|  | select SLAB_OBJ_EXT | 
|  | help | 
|  | Track allocation source code and record total allocation size | 
|  | initiated at that code location. The mechanism can be used to track | 
|  | memory leaks with a low performance and memory impact. | 
|  |  | 
|  | config MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT | 
|  | bool "Enable memory allocation profiling by default" | 
|  | default y | 
|  | depends on MEM_ALLOC_PROFILING | 
|  |  | 
|  | config MEM_ALLOC_PROFILING_DEBUG | 
|  | bool "Memory allocation profiler debugging" | 
|  | default n | 
|  | depends on MEM_ALLOC_PROFILING | 
|  | select MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT | 
|  | help | 
|  | Adds warnings with helpful error messages for memory allocation | 
|  | profiling. | 
|  |  | 
|  | source "lib/Kconfig.kasan" | 
|  | source "lib/Kconfig.kfence" | 
|  | source "lib/Kconfig.kmsan" | 
|  |  | 
|  | endmenu # "Memory Debugging" | 
|  |  | 
|  | config DEBUG_SHIRQ | 
|  | bool "Debug shared IRQ handlers" | 
|  | depends on DEBUG_KERNEL | 
|  | help | 
|  | Enable this to generate a spurious interrupt just before a shared | 
|  | interrupt handler is deregistered (generating one when registering | 
|  | is currently disabled). Drivers need to handle this correctly. Some | 
|  | don't and need to be caught. | 
|  |  | 
|  | menu "Debug Oops, Lockups and Hangs" | 
|  |  | 
|  | config PANIC_ON_OOPS | 
|  | bool "Panic on Oops" | 
|  | help | 
|  | Say Y here to enable the kernel to panic when it oopses. This | 
|  | has the same effect as setting oops=panic on the kernel command | 
|  | line. | 
|  |  | 
|  | This feature is useful to ensure that the kernel does not do | 
|  | anything erroneous after an oops which could result in data | 
|  | corruption or other issues. | 
|  |  | 
|  | Say N if unsure. | 
|  |  | 
|  | config PANIC_ON_OOPS_VALUE | 
|  | int | 
|  | range 0 1 | 
|  | default 0 if !PANIC_ON_OOPS | 
|  | default 1 if PANIC_ON_OOPS | 
|  |  | 
|  | config PANIC_TIMEOUT | 
|  | int "panic timeout" | 
|  | default 0 | 
|  | help | 
|  | Set the timeout value (in seconds) until a reboot occurs when | 
|  | the kernel panics. If n = 0, then we wait forever. A timeout | 
|  | value n > 0 will wait n seconds before rebooting, while a timeout | 
|  | value n < 0 will reboot immediately. This setting can be overridden | 
|  | with the kernel command line option panic=, and from userspace via | 
|  | /proc/sys/kernel/panic. | 
|  |  | 
|  | config LOCKUP_DETECTOR | 
|  | bool | 
|  |  | 
|  | config SOFTLOCKUP_DETECTOR | 
|  | bool "Detect Soft Lockups" | 
|  | depends on DEBUG_KERNEL && !S390 | 
|  | select LOCKUP_DETECTOR | 
|  | help | 
|  | Say Y here to enable the kernel to act as a watchdog to detect | 
|  | soft lockups. | 
|  |  | 
|  | Softlockups are bugs that cause the kernel to loop in kernel | 
|  | mode for more than 20 seconds, without giving other tasks a | 
|  | chance to run.  The current stack trace is displayed upon | 
|  | detection and the system will stay locked up. | 
|  |  | 
|  | config SOFTLOCKUP_DETECTOR_INTR_STORM | 
|  | bool "Detect Interrupt Storm in Soft Lockups" | 
|  | depends on SOFTLOCKUP_DETECTOR && IRQ_TIME_ACCOUNTING | 
|  | select GENERIC_IRQ_STAT_SNAPSHOT | 
|  | default y if NR_CPUS <= 128 | 
|  | help | 
|  | Say Y here to enable the kernel to detect interrupt storm | 
|  | during "soft lockups". | 
|  |  | 
|  | "soft lockups" can be caused by a variety of reasons. If one is | 
|  | caused by an interrupt storm, then the storming interrupts will not | 
|  | be on the callstack. To detect this case, it is necessary to report | 
|  | the CPU stats and the interrupt counts during the "soft lockups". | 
|  |  | 
|  | config BOOTPARAM_SOFTLOCKUP_PANIC | 
|  | bool "Panic (Reboot) On Soft Lockups" | 
|  | depends on SOFTLOCKUP_DETECTOR | 
|  | help | 
|  | Say Y here to enable the kernel to panic on "soft lockups", | 
|  | which are bugs that cause the kernel to loop in kernel | 
|  | mode for more than 20 seconds (configurable using the watchdog_thresh | 
|  | sysctl), without giving other tasks a chance to run. | 
|  |  | 
|  | The panic can be used in combination with panic_timeout, | 
|  | to cause the system to reboot automatically after a | 
|  | lockup has been detected. This feature is useful for | 
|  | high-availability systems that have uptime guarantees and | 
|  | where a lockup must be resolved ASAP. | 
|  |  | 
|  | Say N if unsure. | 
|  |  | 
|  | config HAVE_HARDLOCKUP_DETECTOR_BUDDY | 
|  | bool | 
|  | depends on SMP | 
|  | default y | 
|  |  | 
|  | # | 
|  | # Global switch whether to build a hardlockup detector at all. It is available | 
|  | # only when the architecture supports at least one implementation. There are | 
|  | # two exceptions. The hardlockup detector is never enabled on: | 
|  | # | 
|  | #	s390: it reported many false positives there | 
|  | # | 
|  | #	sparc64: has a custom implementation which is not using the common | 
|  | #		hardlockup command line options and sysctl interface. | 
|  | # | 
|  | config HARDLOCKUP_DETECTOR | 
|  | bool "Detect Hard Lockups" | 
|  | depends on DEBUG_KERNEL && !S390 && !HARDLOCKUP_DETECTOR_SPARC64 | 
|  | depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_BUDDY || HAVE_HARDLOCKUP_DETECTOR_ARCH | 
|  | imply HARDLOCKUP_DETECTOR_PERF | 
|  | imply HARDLOCKUP_DETECTOR_BUDDY | 
|  | imply HARDLOCKUP_DETECTOR_ARCH | 
|  | select LOCKUP_DETECTOR | 
|  |  | 
|  | help | 
|  | Say Y here to enable the kernel to act as a watchdog to detect | 
|  | hard lockups. | 
|  |  | 
|  | Hardlockups are bugs that cause the CPU to loop in kernel mode | 
|  | for more than 10 seconds, without letting other interrupts have a | 
|  | chance to run.  The current stack trace is displayed upon detection | 
|  | and the system will stay locked up. | 
|  |  | 
|  | # | 
|  | # Note that arch-specific variants are always preferred. | 
|  | # | 
|  | config HARDLOCKUP_DETECTOR_PREFER_BUDDY | 
|  | bool "Prefer the buddy CPU hardlockup detector" | 
|  | depends on HARDLOCKUP_DETECTOR | 
|  | depends on HAVE_HARDLOCKUP_DETECTOR_PERF && HAVE_HARDLOCKUP_DETECTOR_BUDDY | 
|  | depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH | 
|  | help | 
|  | Say Y here to prefer the buddy hardlockup detector over the perf one. | 
|  |  | 
|  | With the buddy detector, each CPU uses its softlockup hrtimer | 
|  | to check that the next CPU is processing hrtimer interrupts by | 
|  | verifying that a counter is increasing. | 
|  |  | 
|  | This hardlockup detector is useful on systems that don't have | 
|  | an arch-specific hardlockup detector or if resources needed | 
|  | for the hardlockup detector are better used for other things. | 
|  |  | 
|  | config HARDLOCKUP_DETECTOR_PERF | 
|  | bool | 
|  | depends on HARDLOCKUP_DETECTOR | 
|  | depends on HAVE_HARDLOCKUP_DETECTOR_PERF && !HARDLOCKUP_DETECTOR_PREFER_BUDDY | 
|  | depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH | 
|  | select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER | 
|  |  | 
|  | config HARDLOCKUP_DETECTOR_BUDDY | 
|  | bool | 
|  | depends on HARDLOCKUP_DETECTOR | 
|  | depends on HAVE_HARDLOCKUP_DETECTOR_BUDDY | 
|  | depends on !HAVE_HARDLOCKUP_DETECTOR_PERF || HARDLOCKUP_DETECTOR_PREFER_BUDDY | 
|  | depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH | 
|  | select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER | 
|  |  | 
|  | config HARDLOCKUP_DETECTOR_ARCH | 
|  | bool | 
|  | depends on HARDLOCKUP_DETECTOR | 
|  | depends on HAVE_HARDLOCKUP_DETECTOR_ARCH | 
|  | help | 
|  | The arch-specific implementation of the hardlockup detector will | 
|  | be used. | 
|  |  | 
|  | # | 
|  | # Both the "perf" and "buddy" hardlockup detectors count hrtimer | 
|  | # interrupts. This config enables functions managing this common code. | 
|  | # | 
|  | config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER | 
|  | bool | 
|  | select SOFTLOCKUP_DETECTOR | 
|  |  | 
|  | # | 
|  | # Enables a timestamp based low pass filter to compensate for perf based | 
|  | # hard lockup detection which runs too fast due to turbo modes. | 
|  | # | 
|  | config HARDLOCKUP_CHECK_TIMESTAMP | 
|  | bool | 
|  |  | 
|  | config BOOTPARAM_HARDLOCKUP_PANIC | 
|  | bool "Panic (Reboot) On Hard Lockups" | 
|  | depends on HARDLOCKUP_DETECTOR | 
|  | help | 
|  | Say Y here to enable the kernel to panic on "hard lockups", | 
|  | which are bugs that cause the kernel to loop in kernel | 
|  | mode with interrupts disabled for more than 10 seconds (configurable | 
|  | using the watchdog_thresh sysctl). | 
|  |  | 
|  | Say N if unsure. | 
|  |  | 
|  | config DETECT_HUNG_TASK | 
|  | bool "Detect Hung Tasks" | 
|  | depends on DEBUG_KERNEL | 
|  | default SOFTLOCKUP_DETECTOR | 
|  | help | 
|  | Say Y here to enable the kernel to detect "hung tasks", | 
|  | which are bugs that cause the task to be stuck in | 
|  | uninterruptible "D" state indefinitely. | 
|  |  | 
|  | When a hung task is detected, the kernel will print the | 
|  | current stack trace (which you should report), but the | 
|  | task will stay in uninterruptible state. If lockdep is | 
|  | enabled then all held locks will also be reported. This | 
|  | feature has negligible overhead. | 
|  |  | 
|  | config DEFAULT_HUNG_TASK_TIMEOUT | 
|  | int "Default timeout for hung task detection (in seconds)" | 
|  | depends on DETECT_HUNG_TASK | 
|  | default 120 | 
|  | help | 
|  | This option controls the default timeout (in seconds) used | 
|  | to determine when a task has become non-responsive and should | 
|  | be considered hung. | 
|  |  | 
|  | It can be adjusted at runtime via the kernel.hung_task_timeout_secs | 
|  | sysctl or by writing a value to | 
|  | /proc/sys/kernel/hung_task_timeout_secs. | 
|  |  | 
|  | A timeout of 0 disables the check.  The default is two minutes. | 
|  | Keeping the default should be fine in most cases. | 
|  |  | 
|  | config BOOTPARAM_HUNG_TASK_PANIC | 
|  | bool "Panic (Reboot) On Hung Tasks" | 
|  | depends on DETECT_HUNG_TASK | 
|  | help | 
|  | Say Y here to enable the kernel to panic on "hung tasks", | 
|  | which are bugs that cause the kernel to leave a task stuck | 
|  | in uninterruptible "D" state. | 
|  |  | 
|  | The panic can be used in combination with panic_timeout, | 
|  | to cause the system to reboot automatically after a | 
|  | hung task has been detected. This feature is useful for | 
|  | high-availability systems that have uptime guarantees and | 
|  | where a hung tasks must be resolved ASAP. | 
|  |  | 
|  | Say N if unsure. | 
|  |  | 
|  | config DETECT_HUNG_TASK_BLOCKER | 
|  | bool "Dump Hung Tasks Blocker" | 
|  | depends on DETECT_HUNG_TASK | 
|  | depends on !PREEMPT_RT | 
|  | default y | 
|  | help | 
|  | Say Y here to show the blocker task's stacktrace who acquires | 
|  | the mutex lock which "hung tasks" are waiting. | 
|  | This will add overhead a bit but shows suspicious tasks and | 
|  | call trace if it comes from waiting a mutex. | 
|  |  | 
|  | config WQ_WATCHDOG | 
|  | bool "Detect Workqueue Stalls" | 
|  | depends on DEBUG_KERNEL | 
|  | help | 
|  | Say Y here to enable stall detection on workqueues.  If a | 
|  | worker pool doesn't make forward progress on a pending work | 
|  | item for over a given amount of time, 30s by default, a | 
|  | warning message is printed along with dump of workqueue | 
|  | state.  This can be configured through kernel parameter | 
|  | "workqueue.watchdog_thresh" and its sysfs counterpart. | 
|  |  | 
|  | config WQ_CPU_INTENSIVE_REPORT | 
|  | bool "Report per-cpu work items which hog CPU for too long" | 
|  | depends on DEBUG_KERNEL | 
|  | help | 
|  | Say Y here to enable reporting of concurrency-managed per-cpu work | 
|  | items that hog CPUs for longer than | 
|  | workqueue.cpu_intensive_thresh_us. Workqueue automatically | 
|  | detects and excludes them from concurrency management to prevent | 
|  | them from stalling other per-cpu work items. Occassional | 
|  | triggering may not necessarily indicate a problem. Repeated | 
|  | triggering likely indicates that the work item should be switched | 
|  | to use an unbound workqueue. | 
|  |  | 
|  | config TEST_LOCKUP | 
|  | tristate "Test module to generate lockups" | 
|  | depends on m | 
|  | help | 
|  | This builds the "test_lockup" module that helps to make sure | 
|  | that watchdogs and lockup detectors are working properly. | 
|  |  | 
|  | Depending on module parameters it could emulate soft or hard | 
|  | lockup, "hung task", or locking arbitrary lock for a long time. | 
|  | Also it could generate series of lockups with cooling-down periods. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | endmenu # "Debug lockups and hangs" | 
|  |  | 
|  | menu "Scheduler Debugging" | 
|  |  | 
|  | config SCHED_INFO | 
|  | bool | 
|  | default n | 
|  |  | 
|  | config SCHEDSTATS | 
|  | bool "Collect scheduler statistics" | 
|  | depends on PROC_FS | 
|  | select SCHED_INFO | 
|  | help | 
|  | If you say Y here, additional code will be inserted into the | 
|  | scheduler and related routines to collect statistics about | 
|  | scheduler behavior and provide them in /proc/schedstat.  These | 
|  | stats may be useful for both tuning and debugging the scheduler | 
|  | If you aren't debugging the scheduler or trying to tune a specific | 
|  | application, you can say N to avoid the very slight overhead | 
|  | this adds. | 
|  |  | 
|  | endmenu | 
|  |  | 
|  | config DEBUG_PREEMPT | 
|  | bool "Debug preemptible kernel" | 
|  | depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT | 
|  | help | 
|  | If you say Y here then the kernel will use a debug variant of the | 
|  | commonly used smp_processor_id() function and will print warnings | 
|  | if kernel code uses it in a preemption-unsafe way. Also, the kernel | 
|  | will detect preemption count underflows. | 
|  |  | 
|  | This option has potential to introduce high runtime overhead, | 
|  | depending on workload as it triggers debugging routines for each | 
|  | this_cpu operation. It should only be used for debugging purposes. | 
|  |  | 
|  | menu "Lock Debugging (spinlocks, mutexes, etc...)" | 
|  |  | 
|  | config LOCK_DEBUGGING_SUPPORT | 
|  | bool | 
|  | depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT | 
|  | default y | 
|  |  | 
|  | config PROVE_LOCKING | 
|  | bool "Lock debugging: prove locking correctness" | 
|  | depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT | 
|  | select LOCKDEP | 
|  | select DEBUG_SPINLOCK | 
|  | select DEBUG_MUTEXES if !PREEMPT_RT | 
|  | select DEBUG_RT_MUTEXES if RT_MUTEXES | 
|  | select DEBUG_RWSEMS if !PREEMPT_RT | 
|  | select DEBUG_WW_MUTEX_SLOWPATH | 
|  | select DEBUG_LOCK_ALLOC | 
|  | select PREEMPT_COUNT if !ARCH_NO_PREEMPT | 
|  | select TRACE_IRQFLAGS | 
|  | default n | 
|  | help | 
|  | This feature enables the kernel to prove that all locking | 
|  | that occurs in the kernel runtime is mathematically | 
|  | correct: that under no circumstance could an arbitrary (and | 
|  | not yet triggered) combination of observed locking | 
|  | sequences (on an arbitrary number of CPUs, running an | 
|  | arbitrary number of tasks and interrupt contexts) cause a | 
|  | deadlock. | 
|  |  | 
|  | In short, this feature enables the kernel to report locking | 
|  | related deadlocks before they actually occur. | 
|  |  | 
|  | The proof does not depend on how hard and complex a | 
|  | deadlock scenario would be to trigger: how many | 
|  | participant CPUs, tasks and irq-contexts would be needed | 
|  | for it to trigger. The proof also does not depend on | 
|  | timing: if a race and a resulting deadlock is possible | 
|  | theoretically (no matter how unlikely the race scenario | 
|  | is), it will be proven so and will immediately be | 
|  | reported by the kernel (once the event is observed that | 
|  | makes the deadlock theoretically possible). | 
|  |  | 
|  | If a deadlock is impossible (i.e. the locking rules, as | 
|  | observed by the kernel, are mathematically correct), the | 
|  | kernel reports nothing. | 
|  |  | 
|  | NOTE: this feature can also be enabled for rwlocks, mutexes | 
|  | and rwsems - in which case all dependencies between these | 
|  | different locking variants are observed and mapped too, and | 
|  | the proof of observed correctness is also maintained for an | 
|  | arbitrary combination of these separate locking variants. | 
|  |  | 
|  | For more details, see Documentation/locking/lockdep-design.rst. | 
|  |  | 
|  | config PROVE_RAW_LOCK_NESTING | 
|  | bool "Enable raw_spinlock - spinlock nesting checks" if !ARCH_SUPPORTS_RT | 
|  | depends on PROVE_LOCKING | 
|  | default y if ARCH_SUPPORTS_RT | 
|  | help | 
|  | Enable the raw_spinlock vs. spinlock nesting checks which ensure | 
|  | that the lock nesting rules for PREEMPT_RT enabled kernels are | 
|  | not violated. | 
|  |  | 
|  | config LOCK_STAT | 
|  | bool "Lock usage statistics" | 
|  | depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT | 
|  | select LOCKDEP | 
|  | select DEBUG_SPINLOCK | 
|  | select DEBUG_MUTEXES if !PREEMPT_RT | 
|  | select DEBUG_RT_MUTEXES if RT_MUTEXES | 
|  | select DEBUG_LOCK_ALLOC | 
|  | default n | 
|  | help | 
|  | This feature enables tracking lock contention points | 
|  |  | 
|  | For more details, see Documentation/locking/lockstat.rst | 
|  |  | 
|  | This also enables lock events required by "perf lock", | 
|  | subcommand of perf. | 
|  | If you want to use "perf lock", you also need to turn on | 
|  | CONFIG_EVENT_TRACING. | 
|  |  | 
|  | CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. | 
|  | (CONFIG_LOCKDEP defines "acquire" and "release" events.) | 
|  |  | 
|  | config DEBUG_RT_MUTEXES | 
|  | bool "RT Mutex debugging, deadlock detection" | 
|  | depends on DEBUG_KERNEL && RT_MUTEXES | 
|  | help | 
|  | This allows rt mutex semantics violations and rt mutex related | 
|  | deadlocks (lockups) to be detected and reported automatically. | 
|  |  | 
|  | config DEBUG_SPINLOCK | 
|  | bool "Spinlock and rw-lock debugging: basic checks" | 
|  | depends on DEBUG_KERNEL | 
|  | select UNINLINE_SPIN_UNLOCK | 
|  | help | 
|  | Say Y here and build SMP to catch missing spinlock initialization | 
|  | and certain other kinds of spinlock errors commonly made.  This is | 
|  | best used in conjunction with the NMI watchdog so that spinlock | 
|  | deadlocks are also debuggable. | 
|  |  | 
|  | config DEBUG_MUTEXES | 
|  | bool "Mutex debugging: basic checks" | 
|  | depends on DEBUG_KERNEL && !PREEMPT_RT | 
|  | help | 
|  | This feature allows mutex semantics violations to be detected and | 
|  | reported. | 
|  |  | 
|  | config DEBUG_WW_MUTEX_SLOWPATH | 
|  | bool "Wait/wound mutex debugging: Slowpath testing" | 
|  | depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT | 
|  | select DEBUG_LOCK_ALLOC | 
|  | select DEBUG_SPINLOCK | 
|  | select DEBUG_MUTEXES if !PREEMPT_RT | 
|  | select DEBUG_RT_MUTEXES if PREEMPT_RT | 
|  | help | 
|  | This feature enables slowpath testing for w/w mutex users by | 
|  | injecting additional -EDEADLK wound/backoff cases. Together with | 
|  | the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this | 
|  | will test all possible w/w mutex interface abuse with the | 
|  | exception of simply not acquiring all the required locks. | 
|  | Note that this feature can introduce significant overhead, so | 
|  | it really should not be enabled in a production or distro kernel, | 
|  | even a debug kernel.  If you are a driver writer, enable it.  If | 
|  | you are a distro, do not. | 
|  |  | 
|  | config DEBUG_RWSEMS | 
|  | bool "RW Semaphore debugging: basic checks" | 
|  | depends on DEBUG_KERNEL && !PREEMPT_RT | 
|  | help | 
|  | This debugging feature allows mismatched rw semaphore locks | 
|  | and unlocks to be detected and reported. | 
|  |  | 
|  | config DEBUG_LOCK_ALLOC | 
|  | bool "Lock debugging: detect incorrect freeing of live locks" | 
|  | depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT | 
|  | select DEBUG_SPINLOCK | 
|  | select DEBUG_MUTEXES if !PREEMPT_RT | 
|  | select DEBUG_RT_MUTEXES if RT_MUTEXES | 
|  | select LOCKDEP | 
|  | help | 
|  | This feature will check whether any held lock (spinlock, rwlock, | 
|  | mutex or rwsem) is incorrectly freed by the kernel, via any of the | 
|  | memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), | 
|  | vfree(), etc.), whether a live lock is incorrectly reinitialized via | 
|  | spin_lock_init()/mutex_init()/etc., or whether there is any lock | 
|  | held during task exit. | 
|  |  | 
|  | config LOCKDEP | 
|  | bool | 
|  | depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT | 
|  | select STACKTRACE | 
|  | select KALLSYMS | 
|  | select KALLSYMS_ALL | 
|  |  | 
|  | config LOCKDEP_SMALL | 
|  | bool | 
|  |  | 
|  | config LOCKDEP_BITS | 
|  | int "Size for MAX_LOCKDEP_ENTRIES (as Nth power of 2)" | 
|  | depends on LOCKDEP && !LOCKDEP_SMALL | 
|  | range 10 24 | 
|  | default 15 | 
|  | help | 
|  | Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message. | 
|  |  | 
|  | config LOCKDEP_CHAINS_BITS | 
|  | int "Size for MAX_LOCKDEP_CHAINS (as Nth power of 2)" | 
|  | depends on LOCKDEP && !LOCKDEP_SMALL | 
|  | range 10 21 | 
|  | default 16 | 
|  | help | 
|  | Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message. | 
|  |  | 
|  | config LOCKDEP_STACK_TRACE_BITS | 
|  | int "Size for MAX_STACK_TRACE_ENTRIES (as Nth power of 2)" | 
|  | depends on LOCKDEP && !LOCKDEP_SMALL | 
|  | range 10 26 | 
|  | default 19 | 
|  | help | 
|  | Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message. | 
|  |  | 
|  | config LOCKDEP_STACK_TRACE_HASH_BITS | 
|  | int "Size for STACK_TRACE_HASH_SIZE (as Nth power of 2)" | 
|  | depends on LOCKDEP && !LOCKDEP_SMALL | 
|  | range 10 26 | 
|  | default 14 | 
|  | help | 
|  | Try increasing this value if you need large STACK_TRACE_HASH_SIZE. | 
|  |  | 
|  | config LOCKDEP_CIRCULAR_QUEUE_BITS | 
|  | int "Size for elements in circular_queue struct (as Nth power of 2)" | 
|  | depends on LOCKDEP | 
|  | range 10 26 | 
|  | default 12 | 
|  | help | 
|  | Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure. | 
|  |  | 
|  | config DEBUG_LOCKDEP | 
|  | bool "Lock dependency engine debugging" | 
|  | depends on DEBUG_KERNEL && LOCKDEP | 
|  | select DEBUG_IRQFLAGS | 
|  | help | 
|  | If you say Y here, the lock dependency engine will do | 
|  | additional runtime checks to debug itself, at the price | 
|  | of more runtime overhead. | 
|  |  | 
|  | config DEBUG_ATOMIC_SLEEP | 
|  | bool "Sleep inside atomic section checking" | 
|  | select PREEMPT_COUNT | 
|  | depends on DEBUG_KERNEL | 
|  | depends on !ARCH_NO_PREEMPT | 
|  | help | 
|  | If you say Y here, various routines which may sleep will become very | 
|  | noisy if they are called inside atomic sections: when a spinlock is | 
|  | held, inside an rcu read side critical section, inside preempt disabled | 
|  | sections, inside an interrupt, etc... | 
|  |  | 
|  | config DEBUG_LOCKING_API_SELFTESTS | 
|  | bool "Locking API boot-time self-tests" | 
|  | depends on DEBUG_KERNEL | 
|  | help | 
|  | Say Y here if you want the kernel to run a short self-test during | 
|  | bootup. The self-test checks whether common types of locking bugs | 
|  | are detected by debugging mechanisms or not. (if you disable | 
|  | lock debugging then those bugs won't be detected of course.) | 
|  | The following locking APIs are covered: spinlocks, rwlocks, | 
|  | mutexes and rwsems. | 
|  |  | 
|  | config LOCK_TORTURE_TEST | 
|  | tristate "torture tests for locking" | 
|  | depends on DEBUG_KERNEL | 
|  | select TORTURE_TEST | 
|  | help | 
|  | This option provides a kernel module that runs torture tests | 
|  | on kernel locking primitives.  The kernel module may be built | 
|  | after the fact on the running kernel to be tested, if desired. | 
|  |  | 
|  | Say Y here if you want kernel locking-primitive torture tests | 
|  | to be built into the kernel. | 
|  | Say M if you want these torture tests to build as a module. | 
|  | Say N if you are unsure. | 
|  |  | 
|  | config WW_MUTEX_SELFTEST | 
|  | tristate "Wait/wound mutex selftests" | 
|  | help | 
|  | This option provides a kernel module that runs tests on the | 
|  | on the struct ww_mutex locking API. | 
|  |  | 
|  | It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction | 
|  | with this test harness. | 
|  |  | 
|  | Say M if you want these self tests to build as a module. | 
|  | Say N if you are unsure. | 
|  |  | 
|  | config SCF_TORTURE_TEST | 
|  | tristate "torture tests for smp_call_function*()" | 
|  | depends on DEBUG_KERNEL | 
|  | select TORTURE_TEST | 
|  | help | 
|  | This option provides a kernel module that runs torture tests | 
|  | on the smp_call_function() family of primitives.  The kernel | 
|  | module may be built after the fact on the running kernel to | 
|  | be tested, if desired. | 
|  |  | 
|  | config CSD_LOCK_WAIT_DEBUG | 
|  | bool "Debugging for csd_lock_wait(), called from smp_call_function*()" | 
|  | depends on DEBUG_KERNEL | 
|  | depends on SMP | 
|  | depends on 64BIT | 
|  | default n | 
|  | help | 
|  | This option enables debug prints when CPUs are slow to respond | 
|  | to the smp_call_function*() IPI wrappers.  These debug prints | 
|  | include the IPI handler function currently executing (if any) | 
|  | and relevant stack traces. | 
|  |  | 
|  | config CSD_LOCK_WAIT_DEBUG_DEFAULT | 
|  | bool "Default csd_lock_wait() debugging on at boot time" | 
|  | depends on CSD_LOCK_WAIT_DEBUG | 
|  | depends on 64BIT | 
|  | default n | 
|  | help | 
|  | This option causes the csdlock_debug= kernel boot parameter to | 
|  | default to 1 (basic debugging) instead of 0 (no debugging). | 
|  |  | 
|  | endmenu # lock debugging | 
|  |  | 
|  | config TRACE_IRQFLAGS | 
|  | depends on TRACE_IRQFLAGS_SUPPORT | 
|  | bool | 
|  | help | 
|  | Enables hooks to interrupt enabling and disabling for | 
|  | either tracing or lock debugging. | 
|  |  | 
|  | config TRACE_IRQFLAGS_NMI | 
|  | def_bool y | 
|  | depends on TRACE_IRQFLAGS | 
|  | depends on TRACE_IRQFLAGS_NMI_SUPPORT | 
|  |  | 
|  | config NMI_CHECK_CPU | 
|  | bool "Debugging for CPUs failing to respond to backtrace requests" | 
|  | depends on DEBUG_KERNEL | 
|  | depends on X86 | 
|  | default n | 
|  | help | 
|  | Enables debug prints when a CPU fails to respond to a given | 
|  | backtrace NMI.  These prints provide some reasons why a CPU | 
|  | might legitimately be failing to respond, for example, if it | 
|  | is offline of if ignore_nmis is set. | 
|  |  | 
|  | config DEBUG_IRQFLAGS | 
|  | bool "Debug IRQ flag manipulation" | 
|  | help | 
|  | Enables checks for potentially unsafe enabling or disabling of | 
|  | interrupts, such as calling raw_local_irq_restore() when interrupts | 
|  | are enabled. | 
|  |  | 
|  | config STACKTRACE | 
|  | bool "Stack backtrace support" | 
|  | depends on STACKTRACE_SUPPORT | 
|  | help | 
|  | This option causes the kernel to create a /proc/pid/stack for | 
|  | every process, showing its current stack trace. | 
|  | It is also used by various kernel debugging features that require | 
|  | stack trace generation. | 
|  |  | 
|  | config WARN_ALL_UNSEEDED_RANDOM | 
|  | bool "Warn for all uses of unseeded randomness" | 
|  | default n | 
|  | help | 
|  | Some parts of the kernel contain bugs relating to their use of | 
|  | cryptographically secure random numbers before it's actually possible | 
|  | to generate those numbers securely. This setting ensures that these | 
|  | flaws don't go unnoticed, by enabling a message, should this ever | 
|  | occur. This will allow people with obscure setups to know when things | 
|  | are going wrong, so that they might contact developers about fixing | 
|  | it. | 
|  |  | 
|  | Unfortunately, on some models of some architectures getting | 
|  | a fully seeded CRNG is extremely difficult, and so this can | 
|  | result in dmesg getting spammed for a surprisingly long | 
|  | time.  This is really bad from a security perspective, and | 
|  | so architecture maintainers really need to do what they can | 
|  | to get the CRNG seeded sooner after the system is booted. | 
|  | However, since users cannot do anything actionable to | 
|  | address this, by default this option is disabled. | 
|  |  | 
|  | Say Y here if you want to receive warnings for all uses of | 
|  | unseeded randomness.  This will be of use primarily for | 
|  | those developers interested in improving the security of | 
|  | Linux kernels running on their architecture (or | 
|  | subarchitecture). | 
|  |  | 
|  | config DEBUG_KOBJECT | 
|  | bool "kobject debugging" | 
|  | depends on DEBUG_KERNEL | 
|  | help | 
|  | If you say Y here, some extra kobject debugging messages will be sent | 
|  | to the syslog. | 
|  |  | 
|  | config DEBUG_KOBJECT_RELEASE | 
|  | bool "kobject release debugging" | 
|  | depends on DEBUG_OBJECTS_TIMERS | 
|  | help | 
|  | kobjects are reference counted objects.  This means that their | 
|  | last reference count put is not predictable, and the kobject can | 
|  | live on past the point at which a driver decides to drop its | 
|  | initial reference to the kobject gained on allocation.  An | 
|  | example of this would be a struct device which has just been | 
|  | unregistered. | 
|  |  | 
|  | However, some buggy drivers assume that after such an operation, | 
|  | the memory backing the kobject can be immediately freed.  This | 
|  | goes completely against the principles of a refcounted object. | 
|  |  | 
|  | If you say Y here, the kernel will delay the release of kobjects | 
|  | on the last reference count to improve the visibility of this | 
|  | kind of kobject release bug. | 
|  |  | 
|  | config HAVE_DEBUG_BUGVERBOSE | 
|  | bool | 
|  |  | 
|  | menu "Debug kernel data structures" | 
|  |  | 
|  | config DEBUG_LIST | 
|  | bool "Debug linked list manipulation" | 
|  | depends on DEBUG_KERNEL | 
|  | select LIST_HARDENED | 
|  | help | 
|  | Enable this to turn on extended checks in the linked-list walking | 
|  | routines. | 
|  |  | 
|  | This option trades better quality error reports for performance, and | 
|  | is more suitable for kernel debugging. If you care about performance, | 
|  | you should only enable CONFIG_LIST_HARDENED instead. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config DEBUG_PLIST | 
|  | bool "Debug priority linked list manipulation" | 
|  | depends on DEBUG_KERNEL | 
|  | help | 
|  | Enable this to turn on extended checks in the priority-ordered | 
|  | linked-list (plist) walking routines.  This checks the entire | 
|  | list multiple times during each manipulation. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config DEBUG_SG | 
|  | bool "Debug SG table operations" | 
|  | depends on DEBUG_KERNEL | 
|  | help | 
|  | Enable this to turn on checks on scatter-gather tables. This can | 
|  | help find problems with drivers that do not properly initialize | 
|  | their sg tables. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config DEBUG_NOTIFIERS | 
|  | bool "Debug notifier call chains" | 
|  | depends on DEBUG_KERNEL | 
|  | help | 
|  | Enable this to turn on sanity checking for notifier call chains. | 
|  | This is most useful for kernel developers to make sure that | 
|  | modules properly unregister themselves from notifier chains. | 
|  | This is a relatively cheap check but if you care about maximum | 
|  | performance, say N. | 
|  |  | 
|  | config DEBUG_CLOSURES | 
|  | bool "Debug closures (bcache async widgits)" | 
|  | depends on CLOSURES | 
|  | select DEBUG_FS | 
|  | help | 
|  | Keeps all active closures in a linked list and provides a debugfs | 
|  | interface to list them, which makes it possible to see asynchronous | 
|  | operations that get stuck. | 
|  |  | 
|  | config DEBUG_MAPLE_TREE | 
|  | bool "Debug maple trees" | 
|  | depends on DEBUG_KERNEL | 
|  | help | 
|  | Enable maple tree debugging information and extra validations. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | endmenu | 
|  |  | 
|  | source "kernel/rcu/Kconfig.debug" | 
|  |  | 
|  | config DEBUG_WQ_FORCE_RR_CPU | 
|  | bool "Force round-robin CPU selection for unbound work items" | 
|  | depends on DEBUG_KERNEL | 
|  | default n | 
|  | help | 
|  | Workqueue used to implicitly guarantee that work items queued | 
|  | without explicit CPU specified are put on the local CPU.  This | 
|  | guarantee is no longer true and while local CPU is still | 
|  | preferred work items may be put on foreign CPUs.  Kernel | 
|  | parameter "workqueue.debug_force_rr_cpu" is added to force | 
|  | round-robin CPU selection to flush out usages which depend on the | 
|  | now broken guarantee.  This config option enables the debug | 
|  | feature by default.  When enabled, memory and cache locality will | 
|  | be impacted. | 
|  |  | 
|  | config CPU_HOTPLUG_STATE_CONTROL | 
|  | bool "Enable CPU hotplug state control" | 
|  | depends on DEBUG_KERNEL | 
|  | depends on HOTPLUG_CPU | 
|  | default n | 
|  | help | 
|  | Allows to write steps between "offline" and "online" to the CPUs | 
|  | sysfs target file so states can be stepped granular. This is a debug | 
|  | option for now as the hotplug machinery cannot be stopped and | 
|  | restarted at arbitrary points yet. | 
|  |  | 
|  | Say N if your are unsure. | 
|  |  | 
|  | config LATENCYTOP | 
|  | bool "Latency measuring infrastructure" | 
|  | depends on DEBUG_KERNEL | 
|  | depends on STACKTRACE_SUPPORT | 
|  | depends on PROC_FS | 
|  | depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 | 
|  | select KALLSYMS | 
|  | select KALLSYMS_ALL | 
|  | select STACKTRACE | 
|  | select SCHEDSTATS | 
|  | help | 
|  | Enable this option if you want to use the LatencyTOP tool | 
|  | to find out which userspace is blocking on what kernel operations. | 
|  |  | 
|  | config DEBUG_CGROUP_REF | 
|  | bool "Disable inlining of cgroup css reference count functions" | 
|  | depends on DEBUG_KERNEL | 
|  | depends on CGROUPS | 
|  | depends on KPROBES | 
|  | default n | 
|  | help | 
|  | Force cgroup css reference count functions to not be inlined so | 
|  | that they can be kprobed for debugging. | 
|  |  | 
|  | source "kernel/trace/Kconfig" | 
|  |  | 
|  | config PROVIDE_OHCI1394_DMA_INIT | 
|  | bool "Remote debugging over FireWire early on boot" | 
|  | depends on PCI && X86 | 
|  | help | 
|  | If you want to debug problems which hang or crash the kernel early | 
|  | on boot and the crashing machine has a FireWire port, you can use | 
|  | this feature to remotely access the memory of the crashed machine | 
|  | over FireWire. This employs remote DMA as part of the OHCI1394 | 
|  | specification which is now the standard for FireWire controllers. | 
|  |  | 
|  | With remote DMA, you can monitor the printk buffer remotely using | 
|  | firescope and access all memory below 4GB using fireproxy from gdb. | 
|  | Even controlling a kernel debugger is possible using remote DMA. | 
|  |  | 
|  | Usage: | 
|  |  | 
|  | If ohci1394_dma=early is used as boot parameter, it will initialize | 
|  | all OHCI1394 controllers which are found in the PCI config space. | 
|  |  | 
|  | As all changes to the FireWire bus such as enabling and disabling | 
|  | devices cause a bus reset and thereby disable remote DMA for all | 
|  | devices, be sure to have the cable plugged and FireWire enabled on | 
|  | the debugging host before booting the debug target for debugging. | 
|  |  | 
|  | This code (~1k) is freed after boot. By then, the firewire stack | 
|  | in charge of the OHCI-1394 controllers should be used instead. | 
|  |  | 
|  | See Documentation/core-api/debugging-via-ohci1394.rst for more information. | 
|  |  | 
|  | source "samples/Kconfig" | 
|  |  | 
|  | config ARCH_HAS_DEVMEM_IS_ALLOWED | 
|  | bool | 
|  |  | 
|  | config STRICT_DEVMEM | 
|  | bool "Filter access to /dev/mem" | 
|  | depends on MMU && DEVMEM | 
|  | depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED | 
|  | default y if PPC || X86 || ARM64 || S390 | 
|  | help | 
|  | If this option is disabled, you allow userspace (root) access to all | 
|  | of memory, including kernel and userspace memory. Accidental | 
|  | access to this is obviously disastrous, but specific access can | 
|  | be used by people debugging the kernel. Note that with PAT support | 
|  | enabled, even in this case there are restrictions on /dev/mem | 
|  | use due to the cache aliasing requirements. | 
|  |  | 
|  | If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem | 
|  | file only allows userspace access to PCI space and the BIOS code and | 
|  | data regions.  This is sufficient for dosemu and X and all common | 
|  | users of /dev/mem. | 
|  |  | 
|  | If in doubt, say Y. | 
|  |  | 
|  | config IO_STRICT_DEVMEM | 
|  | bool "Filter I/O access to /dev/mem" | 
|  | depends on STRICT_DEVMEM | 
|  | help | 
|  | If this option is disabled, you allow userspace (root) access to all | 
|  | io-memory regardless of whether a driver is actively using that | 
|  | range.  Accidental access to this is obviously disastrous, but | 
|  | specific access can be used by people debugging kernel drivers. | 
|  |  | 
|  | If this option is switched on, the /dev/mem file only allows | 
|  | userspace access to *idle* io-memory ranges (see /proc/iomem) This | 
|  | may break traditional users of /dev/mem (dosemu, legacy X, etc...) | 
|  | if the driver using a given range cannot be disabled. | 
|  |  | 
|  | If in doubt, say Y. | 
|  |  | 
|  | menu "$(SRCARCH) Debugging" | 
|  |  | 
|  | source "arch/$(SRCARCH)/Kconfig.debug" | 
|  |  | 
|  | endmenu | 
|  |  | 
|  | menu "Kernel Testing and Coverage" | 
|  |  | 
|  | source "lib/kunit/Kconfig" | 
|  |  | 
|  | config NOTIFIER_ERROR_INJECTION | 
|  | tristate "Notifier error injection" | 
|  | depends on DEBUG_KERNEL | 
|  | select DEBUG_FS | 
|  | help | 
|  | This option provides the ability to inject artificial errors to | 
|  | specified notifier chain callbacks. It is useful to test the error | 
|  | handling of notifier call chain failures. | 
|  |  | 
|  | Say N if unsure. | 
|  |  | 
|  | config PM_NOTIFIER_ERROR_INJECT | 
|  | tristate "PM notifier error injection module" | 
|  | depends on PM && NOTIFIER_ERROR_INJECTION | 
|  | default m if PM_DEBUG | 
|  | help | 
|  | This option provides the ability to inject artificial errors to | 
|  | PM notifier chain callbacks.  It is controlled through debugfs | 
|  | interface /sys/kernel/debug/notifier-error-inject/pm | 
|  |  | 
|  | If the notifier call chain should be failed with some events | 
|  | notified, write the error code to "actions/<notifier event>/error". | 
|  |  | 
|  | Example: Inject PM suspend error (-12 = -ENOMEM) | 
|  |  | 
|  | # cd /sys/kernel/debug/notifier-error-inject/pm/ | 
|  | # echo -12 > actions/PM_SUSPEND_PREPARE/error | 
|  | # echo mem > /sys/power/state | 
|  | bash: echo: write error: Cannot allocate memory | 
|  |  | 
|  | To compile this code as a module, choose M here: the module will | 
|  | be called pm-notifier-error-inject. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config OF_RECONFIG_NOTIFIER_ERROR_INJECT | 
|  | tristate "OF reconfig notifier error injection module" | 
|  | depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION | 
|  | help | 
|  | This option provides the ability to inject artificial errors to | 
|  | OF reconfig notifier chain callbacks.  It is controlled | 
|  | through debugfs interface under | 
|  | /sys/kernel/debug/notifier-error-inject/OF-reconfig/ | 
|  |  | 
|  | If the notifier call chain should be failed with some events | 
|  | notified, write the error code to "actions/<notifier event>/error". | 
|  |  | 
|  | To compile this code as a module, choose M here: the module will | 
|  | be called of-reconfig-notifier-error-inject. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config NETDEV_NOTIFIER_ERROR_INJECT | 
|  | tristate "Netdev notifier error injection module" | 
|  | depends on NET && NOTIFIER_ERROR_INJECTION | 
|  | help | 
|  | This option provides the ability to inject artificial errors to | 
|  | netdevice notifier chain callbacks.  It is controlled through debugfs | 
|  | interface /sys/kernel/debug/notifier-error-inject/netdev | 
|  |  | 
|  | If the notifier call chain should be failed with some events | 
|  | notified, write the error code to "actions/<notifier event>/error". | 
|  |  | 
|  | Example: Inject netdevice mtu change error (-22 = -EINVAL) | 
|  |  | 
|  | # cd /sys/kernel/debug/notifier-error-inject/netdev | 
|  | # echo -22 > actions/NETDEV_CHANGEMTU/error | 
|  | # ip link set eth0 mtu 1024 | 
|  | RTNETLINK answers: Invalid argument | 
|  |  | 
|  | To compile this code as a module, choose M here: the module will | 
|  | be called netdev-notifier-error-inject. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config FUNCTION_ERROR_INJECTION | 
|  | bool "Fault-injections of functions" | 
|  | depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES | 
|  | help | 
|  | Add fault injections into various functions that are annotated with | 
|  | ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return | 
|  | value of these functions. This is useful to test error paths of code. | 
|  |  | 
|  | If unsure, say N | 
|  |  | 
|  | config FAULT_INJECTION | 
|  | bool "Fault-injection framework" | 
|  | depends on DEBUG_KERNEL | 
|  | help | 
|  | Provide fault-injection framework. | 
|  | For more details, see Documentation/fault-injection/. | 
|  |  | 
|  | config FAILSLAB | 
|  | bool "Fault-injection capability for kmalloc" | 
|  | depends on FAULT_INJECTION | 
|  | help | 
|  | Provide fault-injection capability for kmalloc. | 
|  |  | 
|  | config FAIL_PAGE_ALLOC | 
|  | bool "Fault-injection capability for alloc_pages()" | 
|  | depends on FAULT_INJECTION | 
|  | help | 
|  | Provide fault-injection capability for alloc_pages(). | 
|  |  | 
|  | config FAULT_INJECTION_USERCOPY | 
|  | bool "Fault injection capability for usercopy functions" | 
|  | depends on FAULT_INJECTION | 
|  | help | 
|  | Provides fault-injection capability to inject failures | 
|  | in usercopy functions (copy_from_user(), get_user(), ...). | 
|  |  | 
|  | config FAIL_MAKE_REQUEST | 
|  | bool "Fault-injection capability for disk IO" | 
|  | depends on FAULT_INJECTION && BLOCK | 
|  | help | 
|  | Provide fault-injection capability for disk IO. | 
|  |  | 
|  | config FAIL_IO_TIMEOUT | 
|  | bool "Fault-injection capability for faking disk interrupts" | 
|  | depends on FAULT_INJECTION && BLOCK | 
|  | help | 
|  | Provide fault-injection capability on end IO handling. This | 
|  | will make the block layer "forget" an interrupt as configured, | 
|  | thus exercising the error handling. | 
|  |  | 
|  | Only works with drivers that use the generic timeout handling, | 
|  | for others it won't do anything. | 
|  |  | 
|  | config FAIL_FUTEX | 
|  | bool "Fault-injection capability for futexes" | 
|  | select DEBUG_FS | 
|  | depends on FAULT_INJECTION && FUTEX | 
|  | help | 
|  | Provide fault-injection capability for futexes. | 
|  |  | 
|  | config FAULT_INJECTION_DEBUG_FS | 
|  | bool "Debugfs entries for fault-injection capabilities" | 
|  | depends on FAULT_INJECTION && SYSFS && DEBUG_FS | 
|  | help | 
|  | Enable configuration of fault-injection capabilities via debugfs. | 
|  |  | 
|  | config FAIL_FUNCTION | 
|  | bool "Fault-injection capability for functions" | 
|  | depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION | 
|  | help | 
|  | Provide function-based fault-injection capability. | 
|  | This will allow you to override a specific function with a return | 
|  | with given return value. As a result, function caller will see | 
|  | an error value and have to handle it. This is useful to test the | 
|  | error handling in various subsystems. | 
|  |  | 
|  | config FAIL_MMC_REQUEST | 
|  | bool "Fault-injection capability for MMC IO" | 
|  | depends on FAULT_INJECTION_DEBUG_FS && MMC | 
|  | help | 
|  | Provide fault-injection capability for MMC IO. | 
|  | This will make the mmc core return data errors. This is | 
|  | useful to test the error handling in the mmc block device | 
|  | and to test how the mmc host driver handles retries from | 
|  | the block device. | 
|  |  | 
|  | config FAIL_SUNRPC | 
|  | bool "Fault-injection capability for SunRPC" | 
|  | depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG | 
|  | help | 
|  | Provide fault-injection capability for SunRPC and | 
|  | its consumers. | 
|  |  | 
|  | config FAIL_SKB_REALLOC | 
|  | bool "Fault-injection capability forcing skb to reallocate" | 
|  | depends on FAULT_INJECTION_DEBUG_FS | 
|  | help | 
|  | Provide fault-injection capability that forces the skb to be | 
|  | reallocated, catching possible invalid pointers to the skb. | 
|  |  | 
|  | For more information, check | 
|  | Documentation/fault-injection/fault-injection.rst | 
|  |  | 
|  | config FAULT_INJECTION_CONFIGFS | 
|  | bool "Configfs interface for fault-injection capabilities" | 
|  | depends on FAULT_INJECTION | 
|  | select CONFIGFS_FS | 
|  | help | 
|  | This option allows configfs-based drivers to dynamically configure | 
|  | fault-injection via configfs.  Each parameter for driver-specific | 
|  | fault-injection can be made visible as a configfs attribute in a | 
|  | configfs group. | 
|  |  | 
|  |  | 
|  | config FAULT_INJECTION_STACKTRACE_FILTER | 
|  | bool "stacktrace filter for fault-injection capabilities" | 
|  | depends on FAULT_INJECTION | 
|  | depends on (FAULT_INJECTION_DEBUG_FS || FAULT_INJECTION_CONFIGFS) && STACKTRACE_SUPPORT | 
|  | select STACKTRACE | 
|  | depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 | 
|  | help | 
|  | Provide stacktrace filter for fault-injection capabilities | 
|  |  | 
|  | config ARCH_HAS_KCOV | 
|  | bool | 
|  | help | 
|  | An architecture should select this when it can successfully | 
|  | build and run with CONFIG_KCOV. This typically requires | 
|  | disabling instrumentation for some early boot code. | 
|  |  | 
|  | config KCOV | 
|  | bool "Code coverage for fuzzing" | 
|  | depends on ARCH_HAS_KCOV | 
|  | depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \ | 
|  | GCC_VERSION >= 120000 || CC_IS_CLANG | 
|  | select DEBUG_FS | 
|  | select OBJTOOL if HAVE_NOINSTR_HACK | 
|  | help | 
|  | KCOV exposes kernel code coverage information in a form suitable | 
|  | for coverage-guided fuzzing (randomized testing). | 
|  |  | 
|  | For more details, see Documentation/dev-tools/kcov.rst. | 
|  |  | 
|  | config KCOV_ENABLE_COMPARISONS | 
|  | bool "Enable comparison operands collection by KCOV" | 
|  | depends on KCOV | 
|  | depends on $(cc-option,-fsanitize-coverage=trace-cmp) | 
|  | help | 
|  | KCOV also exposes operands of every comparison in the instrumented | 
|  | code along with operand sizes and PCs of the comparison instructions. | 
|  | These operands can be used by fuzzing engines to improve the quality | 
|  | of fuzzing coverage. | 
|  |  | 
|  | config KCOV_INSTRUMENT_ALL | 
|  | bool "Instrument all code by default" | 
|  | depends on KCOV | 
|  | default y | 
|  | help | 
|  | If you are doing generic system call fuzzing (like e.g. syzkaller), | 
|  | then you will want to instrument the whole kernel and you should | 
|  | say y here. If you are doing more targeted fuzzing (like e.g. | 
|  | filesystem fuzzing with AFL) then you will want to enable coverage | 
|  | for more specific subsets of files, and should say n here. | 
|  |  | 
|  | config KCOV_IRQ_AREA_SIZE | 
|  | hex "Size of interrupt coverage collection area in words" | 
|  | depends on KCOV | 
|  | default 0x40000 | 
|  | help | 
|  | KCOV uses preallocated per-cpu areas to collect coverage from | 
|  | soft interrupts. This specifies the size of those areas in the | 
|  | number of unsigned long words. | 
|  |  | 
|  | config KCOV_SELFTEST | 
|  | bool "Perform short selftests on boot" | 
|  | depends on KCOV | 
|  | help | 
|  | Run short KCOV coverage collection selftests on boot. | 
|  | On test failure, causes the kernel to panic. Recommended to be | 
|  | enabled, ensuring critical functionality works as intended. | 
|  |  | 
|  | menuconfig RUNTIME_TESTING_MENU | 
|  | bool "Runtime Testing" | 
|  | default y | 
|  |  | 
|  | if RUNTIME_TESTING_MENU | 
|  |  | 
|  | config TEST_DHRY | 
|  | tristate "Dhrystone benchmark test" | 
|  | help | 
|  | Enable this to include the Dhrystone 2.1 benchmark.  This test | 
|  | calculates the number of Dhrystones per second, and the number of | 
|  | DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided | 
|  | by 1757 (the number of Dhrystones per second obtained on the VAX | 
|  | 11/780, nominally a 1 MIPS machine). | 
|  |  | 
|  | To run the benchmark, it needs to be enabled explicitly, either from | 
|  | the kernel command line (when built-in), or from userspace (when | 
|  | built-in or modular). | 
|  |  | 
|  | Run once during kernel boot: | 
|  |  | 
|  | test_dhry.run | 
|  |  | 
|  | Set number of iterations from kernel command line: | 
|  |  | 
|  | test_dhry.iterations=<n> | 
|  |  | 
|  | Set number of iterations from userspace: | 
|  |  | 
|  | echo <n> > /sys/module/test_dhry/parameters/iterations | 
|  |  | 
|  | Trigger manual run from userspace: | 
|  |  | 
|  | echo y > /sys/module/test_dhry/parameters/run | 
|  |  | 
|  | If the number of iterations is <= 0, the test will devise a suitable | 
|  | number of iterations (test runs for at least 2s) automatically. | 
|  | This process takes ca. 4s. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config LKDTM | 
|  | tristate "Linux Kernel Dump Test Tool Module" | 
|  | depends on DEBUG_FS | 
|  | help | 
|  | This module enables testing of the different dumping mechanisms by | 
|  | inducing system failures at predefined crash points. | 
|  | If you don't need it: say N | 
|  | Choose M here to compile this code as a module. The module will be | 
|  | called lkdtm. | 
|  |  | 
|  | Documentation on how to use the module can be found in | 
|  | Documentation/fault-injection/provoke-crashes.rst | 
|  |  | 
|  | config CPUMASK_KUNIT_TEST | 
|  | tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | Enable to turn on cpumask tests, running at boot or module load time. | 
|  |  | 
|  | For more information on KUnit and unit tests in general, please refer | 
|  | to the KUnit documentation in Documentation/dev-tools/kunit/. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_LIST_SORT | 
|  | tristate "Linked list sorting test" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | Enable this to turn on 'list_sort()' function test. This test is | 
|  | executed only once during system boot (so affects only boot time), | 
|  | or at module load time. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_MIN_HEAP | 
|  | tristate "Min heap test" | 
|  | depends on DEBUG_KERNEL || m | 
|  | help | 
|  | Enable this to turn on min heap function tests. This test is | 
|  | executed only once during system boot (so affects only boot time), | 
|  | or at module load time. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_SORT | 
|  | tristate "Array-based sort test" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | This option enables the self-test function of 'sort()' at boot, | 
|  | or at module load time. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_DIV64 | 
|  | tristate "64bit/32bit division and modulo test" | 
|  | depends on DEBUG_KERNEL || m | 
|  | help | 
|  | Enable this to turn on 'do_div()' function test. This test is | 
|  | executed only once during system boot (so affects only boot time), | 
|  | or at module load time. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_MULDIV64 | 
|  | tristate "mul_u64_u64_div_u64() test" | 
|  | depends on DEBUG_KERNEL || m | 
|  | help | 
|  | Enable this to turn on 'mul_u64_u64_div_u64()' function test. | 
|  | This test is executed only once during system boot (so affects | 
|  | only boot time), or at module load time. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_IOV_ITER | 
|  | tristate "Test iov_iter operation" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | depends on MMU | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | Enable this to turn on testing of the operation of the I/O iterator | 
|  | (iov_iter). This test is executed only once during system boot (so | 
|  | affects only boot time), or at module load time. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config KPROBES_SANITY_TEST | 
|  | tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS | 
|  | depends on DEBUG_KERNEL | 
|  | depends on KPROBES | 
|  | depends on KUNIT | 
|  | select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | This option provides for testing basic kprobes functionality on | 
|  | boot. Samples of kprobe and kretprobe are inserted and | 
|  | verified for functionality. | 
|  |  | 
|  | Say N if you are unsure. | 
|  |  | 
|  | config FPROBE_SANITY_TEST | 
|  | bool "Self test for fprobe" | 
|  | depends on DEBUG_KERNEL | 
|  | depends on FPROBE | 
|  | depends on KUNIT=y | 
|  | help | 
|  | This option will enable testing the fprobe when the system boot. | 
|  | A series of tests are made to verify that the fprobe is functioning | 
|  | properly. | 
|  |  | 
|  | Say N if you are unsure. | 
|  |  | 
|  | config BACKTRACE_SELF_TEST | 
|  | tristate "Self test for the backtrace code" | 
|  | depends on DEBUG_KERNEL | 
|  | help | 
|  | This option provides a kernel module that can be used to test | 
|  | the kernel stack backtrace code. This option is not useful | 
|  | for distributions or general kernels, but only for kernel | 
|  | developers working on architecture code. | 
|  |  | 
|  | Note that if you want to also test saved backtraces, you will | 
|  | have to enable STACKTRACE as well. | 
|  |  | 
|  | Say N if you are unsure. | 
|  |  | 
|  | config TEST_REF_TRACKER | 
|  | tristate "Self test for reference tracker" | 
|  | depends on DEBUG_KERNEL && STACKTRACE_SUPPORT | 
|  | select REF_TRACKER | 
|  | help | 
|  | This option provides a kernel module performing tests | 
|  | using reference tracker infrastructure. | 
|  |  | 
|  | Say N if you are unsure. | 
|  |  | 
|  | config RBTREE_TEST | 
|  | tristate "Red-Black tree test" | 
|  | depends on DEBUG_KERNEL | 
|  | help | 
|  | A benchmark measuring the performance of the rbtree library. | 
|  | Also includes rbtree invariant checks. | 
|  |  | 
|  | config REED_SOLOMON_TEST | 
|  | tristate "Reed-Solomon library test" | 
|  | depends on DEBUG_KERNEL || m | 
|  | select REED_SOLOMON | 
|  | select REED_SOLOMON_ENC16 | 
|  | select REED_SOLOMON_DEC16 | 
|  | help | 
|  | This option enables the self-test function of rslib at boot, | 
|  | or at module load time. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config INTERVAL_TREE_TEST | 
|  | tristate "Interval tree test" | 
|  | depends on DEBUG_KERNEL | 
|  | select INTERVAL_TREE | 
|  | help | 
|  | A benchmark measuring the performance of the interval tree library | 
|  |  | 
|  | config PERCPU_TEST | 
|  | tristate "Per cpu operations test" | 
|  | depends on m && DEBUG_KERNEL | 
|  | help | 
|  | Enable this option to build test module which validates per-cpu | 
|  | operations. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config ATOMIC64_SELFTEST | 
|  | tristate "Perform an atomic64_t self-test" | 
|  | help | 
|  | Enable this option to test the atomic64_t functions at boot or | 
|  | at module load time. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config ASYNC_RAID6_TEST | 
|  | tristate "Self test for hardware accelerated raid6 recovery" | 
|  | depends on ASYNC_RAID6_RECOV | 
|  | select ASYNC_MEMCPY | 
|  | help | 
|  | This is a one-shot self test that permutes through the | 
|  | recovery of all the possible two disk failure scenarios for a | 
|  | N-disk array.  Recovery is performed with the asynchronous | 
|  | raid6 recovery routines, and will optionally use an offload | 
|  | engine if one is available. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_HEXDUMP | 
|  | tristate "Test functions located in the hexdump module at runtime" | 
|  |  | 
|  | config PRINTF_KUNIT_TEST | 
|  | tristate "KUnit test printf() family of functions at runtime" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | Enable this option to test the printf functions at runtime. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config SCANF_KUNIT_TEST | 
|  | tristate "KUnit test scanf() family of functions at runtime" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | Enable this option to test the scanf functions at runtime. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config SEQ_BUF_KUNIT_TEST | 
|  | tristate "KUnit test for seq_buf" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | This builds unit tests for the seq_buf library. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config STRING_KUNIT_TEST | 
|  | tristate "KUnit test string functions at runtime" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  |  | 
|  | config STRING_HELPERS_KUNIT_TEST | 
|  | tristate "KUnit test string helpers at runtime" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  |  | 
|  | config TEST_KSTRTOX | 
|  | tristate "Test kstrto*() family of functions at runtime" | 
|  |  | 
|  | config TEST_BITMAP | 
|  | tristate "Test bitmap_*() family of functions at runtime" | 
|  | help | 
|  | Enable this option to test the bitmap functions at boot. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_UUID | 
|  | tristate "Test functions located in the uuid module at runtime" | 
|  |  | 
|  | config TEST_XARRAY | 
|  | tristate "Test the XArray code at runtime" | 
|  |  | 
|  | config TEST_MAPLE_TREE | 
|  | tristate "Test the Maple Tree code at runtime or module load" | 
|  | help | 
|  | Enable this option to test the maple tree code functions at boot, or | 
|  | when the module is loaded. Enable "Debug Maple Trees" will enable | 
|  | more verbose output on failures. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_RHASHTABLE | 
|  | tristate "Perform selftest on resizable hash table" | 
|  | help | 
|  | Enable this option to test the rhashtable functions at boot. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_IDA | 
|  | tristate "Perform selftest on IDA functions" | 
|  |  | 
|  | config TEST_MISC_MINOR | 
|  | bool "miscdevice KUnit test" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT=y | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | Kunit test for miscdevice API, specially its behavior in respect to | 
|  | static and dynamic minor numbers. | 
|  |  | 
|  | KUnit tests run during boot and output the results to the debug log | 
|  | in TAP format (https://testanything.org/). Only useful for kernel devs | 
|  | running the KUnit test harness, and not intended for inclusion into a | 
|  | production build. | 
|  |  | 
|  | For more information on KUnit and unit tests in general please refer | 
|  | to the KUnit documentation in Documentation/dev-tools/kunit/. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_PARMAN | 
|  | tristate "Perform selftest on priority array manager" | 
|  | depends on PARMAN | 
|  | help | 
|  | Enable this option to test priority array manager on boot | 
|  | (or module load). | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_IRQ_TIMINGS | 
|  | bool "IRQ timings selftest" | 
|  | depends on IRQ_TIMINGS | 
|  | help | 
|  | Enable this option to test the irq timings code on boot. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_LKM | 
|  | tristate "Test module loading with 'hello world' module" | 
|  | depends on m | 
|  | help | 
|  | This builds the "test_module" module that emits "Hello, world" | 
|  | on printk when loaded. It is designed to be used for basic | 
|  | evaluation of the module loading subsystem (for example when | 
|  | validating module verification). It lacks any extra dependencies, | 
|  | and will not normally be loaded by the system unless explicitly | 
|  | requested by name. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_BITOPS | 
|  | tristate "Test module for compilation of bitops operations" | 
|  | help | 
|  | This builds the "test_bitops" module that is much like the | 
|  | TEST_LKM module except that it does a basic exercise of the | 
|  | set/clear_bit macros and get_count_order/long to make sure there are | 
|  | no compiler warnings from C=1 sparse checker or -Wextra | 
|  | compilations. It has no dependencies and doesn't run or load unless | 
|  | explicitly requested by name.  for example: modprobe test_bitops. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_VMALLOC | 
|  | tristate "Test module for stress/performance analysis of vmalloc allocator" | 
|  | default n | 
|  | depends on MMU | 
|  | help | 
|  | This builds the "test_vmalloc" module that should be used for | 
|  | stress and performance analysis. So, any new change for vmalloc | 
|  | subsystem can be evaluated from performance and stability point | 
|  | of view. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_BPF | 
|  | tristate "Test BPF filter functionality" | 
|  | depends on m && NET | 
|  | help | 
|  | This builds the "test_bpf" module that runs various test vectors | 
|  | against the BPF interpreter or BPF JIT compiler depending on the | 
|  | current setting. This is in particular useful for BPF JIT compiler | 
|  | development, but also to run regression tests against changes in | 
|  | the interpreter code. It also enables test stubs for eBPF maps and | 
|  | verifier used by user space verifier testsuite. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config FIND_BIT_BENCHMARK | 
|  | tristate "Test find_bit functions" | 
|  | help | 
|  | This builds the "test_find_bit" module that measure find_*_bit() | 
|  | functions performance. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_FIRMWARE | 
|  | tristate "Test firmware loading via userspace interface" | 
|  | depends on FW_LOADER | 
|  | help | 
|  | This builds the "test_firmware" module that creates a userspace | 
|  | interface for testing firmware loading. This can be used to | 
|  | control the triggering of firmware loading without needing an | 
|  | actual firmware-using device. The contents can be rechecked by | 
|  | userspace. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_SYSCTL | 
|  | tristate "sysctl test driver" | 
|  | depends on PROC_SYSCTL | 
|  | help | 
|  | This builds the "test_sysctl" module. This driver enables to test the | 
|  | proc sysctl interfaces available to drivers safely without affecting | 
|  | production knobs which might alter system functionality. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config BITFIELD_KUNIT | 
|  | tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | Enable this option to test the bitfield functions at boot. | 
|  |  | 
|  | KUnit tests run during boot and output the results to the debug log | 
|  | in TAP format (http://testanything.org/). Only useful for kernel devs | 
|  | running the KUnit test harness, and not intended for inclusion into a | 
|  | production build. | 
|  |  | 
|  | For more information on KUnit and unit tests in general please refer | 
|  | to the KUnit documentation in Documentation/dev-tools/kunit/. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config CHECKSUM_KUNIT | 
|  | tristate "KUnit test checksum functions at runtime" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | Enable this option to test the checksum functions at boot. | 
|  |  | 
|  | KUnit tests run during boot and output the results to the debug log | 
|  | in TAP format (http://testanything.org/). Only useful for kernel devs | 
|  | running the KUnit test harness, and not intended for inclusion into a | 
|  | production build. | 
|  |  | 
|  | For more information on KUnit and unit tests in general please refer | 
|  | to the KUnit documentation in Documentation/dev-tools/kunit/. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config UTIL_MACROS_KUNIT | 
|  | tristate "KUnit test util_macros.h functions at runtime" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | Enable this option to test the util_macros.h function at boot. | 
|  |  | 
|  | KUnit tests run during boot and output the results to the debug log | 
|  | in TAP format (http://testanything.org/). Only useful for kernel devs | 
|  | running the KUnit test harness, and not intended for inclusion into a | 
|  | production build. | 
|  |  | 
|  | For more information on KUnit and unit tests in general please refer | 
|  | to the KUnit documentation in Documentation/dev-tools/kunit/. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config HASH_KUNIT_TEST | 
|  | tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | Enable this option to test the kernel's string (<linux/stringhash.h>), and | 
|  | integer (<linux/hash.h>) hash functions on boot. | 
|  |  | 
|  | KUnit tests run during boot and output the results to the debug log | 
|  | in TAP format (https://testanything.org/). Only useful for kernel devs | 
|  | running the KUnit test harness, and not intended for inclusion into a | 
|  | production build. | 
|  |  | 
|  | For more information on KUnit and unit tests in general please refer | 
|  | to the KUnit documentation in Documentation/dev-tools/kunit/. | 
|  |  | 
|  | This is intended to help people writing architecture-specific | 
|  | optimized versions. If unsure, say N. | 
|  |  | 
|  | config RESOURCE_KUNIT_TEST | 
|  | tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | select GET_FREE_REGION | 
|  | help | 
|  | This builds the resource API unit test. | 
|  | Tests the logic of API provided by resource.c and ioport.h. | 
|  | For more information on KUnit and unit tests in general please refer | 
|  | to the KUnit documentation in Documentation/dev-tools/kunit/. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config SYSCTL_KUNIT_TEST | 
|  | tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | This builds the proc sysctl unit test, which runs on boot. | 
|  | Tests the API contract and implementation correctness of sysctl. | 
|  | For more information on KUnit and unit tests in general please refer | 
|  | to the KUnit documentation in Documentation/dev-tools/kunit/. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config KFIFO_KUNIT_TEST | 
|  | tristate "KUnit Test for the generic kernel FIFO implementation" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | This builds the generic FIFO implementation KUnit test suite. | 
|  | It tests that the API and basic functionality of the kfifo type | 
|  | and associated macros. | 
|  |  | 
|  | For more information on KUnit and unit tests in general please refer | 
|  | to the KUnit documentation in Documentation/dev-tools/kunit/. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config LIST_KUNIT_TEST | 
|  | tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | This builds the linked list KUnit test suite. | 
|  | It tests that the API and basic functionality of the list_head type | 
|  | and associated macros. | 
|  |  | 
|  | KUnit tests run during boot and output the results to the debug log | 
|  | in TAP format (https://testanything.org/). Only useful for kernel devs | 
|  | running the KUnit test harness, and not intended for inclusion into a | 
|  | production build. | 
|  |  | 
|  | For more information on KUnit and unit tests in general please refer | 
|  | to the KUnit documentation in Documentation/dev-tools/kunit/. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config HASHTABLE_KUNIT_TEST | 
|  | tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | This builds the hashtable KUnit test suite. | 
|  | It tests the basic functionality of the API defined in | 
|  | include/linux/hashtable.h. For more information on KUnit and | 
|  | unit tests in general please refer to the KUnit documentation | 
|  | in Documentation/dev-tools/kunit/. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config LINEAR_RANGES_TEST | 
|  | tristate "KUnit test for linear_ranges" | 
|  | depends on KUNIT | 
|  | select LINEAR_RANGES | 
|  | help | 
|  | This builds the linear_ranges unit test, which runs on boot. | 
|  | Tests the linear_ranges logic correctness. | 
|  | For more information on KUnit and unit tests in general please refer | 
|  | to the KUnit documentation in Documentation/dev-tools/kunit/. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config CMDLINE_KUNIT_TEST | 
|  | tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | This builds the cmdline API unit test. | 
|  | Tests the logic of API provided by cmdline.c. | 
|  | For more information on KUnit and unit tests in general please refer | 
|  | to the KUnit documentation in Documentation/dev-tools/kunit/. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config BITS_TEST | 
|  | tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | This builds the bits unit test. | 
|  | Tests the logic of macros defined in bits.h. | 
|  | For more information on KUnit and unit tests in general please refer | 
|  | to the KUnit documentation in Documentation/dev-tools/kunit/. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config SLUB_KUNIT_TEST | 
|  | tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS | 
|  | depends on SLUB_DEBUG && KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | This builds SLUB allocator unit test. | 
|  | Tests SLUB cache debugging functionality. | 
|  | For more information on KUnit and unit tests in general please refer | 
|  | to the KUnit documentation in Documentation/dev-tools/kunit/. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config RATIONAL_KUNIT_TEST | 
|  | tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT && RATIONAL | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | This builds the rational math unit test. | 
|  | For more information on KUnit and unit tests in general please refer | 
|  | to the KUnit documentation in Documentation/dev-tools/kunit/. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config MEMCPY_KUNIT_TEST | 
|  | tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | Builds unit tests for memcpy(), memmove(), and memset() functions. | 
|  | For more information on KUnit and unit tests in general please refer | 
|  | to the KUnit documentation in Documentation/dev-tools/kunit/. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config IS_SIGNED_TYPE_KUNIT_TEST | 
|  | tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | Builds unit tests for the is_signed_type() macro. | 
|  |  | 
|  | For more information on KUnit and unit tests in general please refer | 
|  | to the KUnit documentation in Documentation/dev-tools/kunit/. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config OVERFLOW_KUNIT_TEST | 
|  | tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | Builds unit tests for the check_*_overflow(), size_*(), allocation, and | 
|  | related functions. | 
|  |  | 
|  | For more information on KUnit and unit tests in general please refer | 
|  | to the KUnit documentation in Documentation/dev-tools/kunit/. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config RANDSTRUCT_KUNIT_TEST | 
|  | tristate "Test randstruct structure layout randomization at runtime" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | Builds unit tests for the checking CONFIG_RANDSTRUCT=y, which | 
|  | randomizes structure layouts. | 
|  |  | 
|  | config STACKINIT_KUNIT_TEST | 
|  | tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | Test if the kernel is zero-initializing stack variables and | 
|  | padding. Coverage is controlled by compiler flags, | 
|  | CONFIG_INIT_STACK_ALL_PATTERN or CONFIG_INIT_STACK_ALL_ZERO. | 
|  |  | 
|  | config FORTIFY_KUNIT_TEST | 
|  | tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | Builds unit tests for checking internals of FORTIFY_SOURCE as used | 
|  | by the str*() and mem*() family of functions. For testing runtime | 
|  | traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests. | 
|  |  | 
|  | config LONGEST_SYM_KUNIT_TEST | 
|  | tristate "Test the longest symbol possible" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT && KPROBES | 
|  | depends on !PREFIX_SYMBOLS && !CFI_CLANG && !GCOV_KERNEL | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | Tests the longest symbol possible | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config HW_BREAKPOINT_KUNIT_TEST | 
|  | bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS | 
|  | depends on HAVE_HW_BREAKPOINT | 
|  | depends on KUNIT=y | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | Tests for hw_breakpoint constraints accounting. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config SIPHASH_KUNIT_TEST | 
|  | tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | Enable this option to test the kernel's siphash (<linux/siphash.h>) hash | 
|  | functions on boot (or module load). | 
|  |  | 
|  | This is intended to help people writing architecture-specific | 
|  | optimized versions.  If unsure, say N. | 
|  |  | 
|  | config USERCOPY_KUNIT_TEST | 
|  | tristate "KUnit Test for user/kernel boundary protections" | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | This builds the "usercopy_kunit" module that runs sanity checks | 
|  | on the copy_to/from_user infrastructure, making sure basic | 
|  | user/kernel boundary testing is working. | 
|  |  | 
|  | config BLACKHOLE_DEV_KUNIT_TEST | 
|  | tristate "Test blackhole netdev functionality" if !KUNIT_ALL_TESTS | 
|  | depends on NET | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | This builds the "blackhole_dev_kunit" module that validates the | 
|  | data path through this blackhole netdev. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_UDELAY | 
|  | tristate "udelay test driver" | 
|  | help | 
|  | This builds the "udelay_test" module that helps to make sure | 
|  | that udelay() is working properly. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_STATIC_KEYS | 
|  | tristate "Test static keys" | 
|  | depends on m | 
|  | help | 
|  | Test the static key interfaces. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_DYNAMIC_DEBUG | 
|  | tristate "Test DYNAMIC_DEBUG" | 
|  | depends on DYNAMIC_DEBUG | 
|  | help | 
|  | This module registers a tracer callback to count enabled | 
|  | pr_debugs in a 'do_debugging' function, then alters their | 
|  | enablements, calls the function, and compares counts. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_KMOD | 
|  | tristate "kmod stress tester" | 
|  | depends on m | 
|  | select TEST_LKM | 
|  | help | 
|  | Test the kernel's module loading mechanism: kmod. kmod implements | 
|  | support to load modules using the Linux kernel's usermode helper. | 
|  | This test provides a series of tests against kmod. | 
|  |  | 
|  | Although technically you can either build test_kmod as a module or | 
|  | into the kernel we disallow building it into the kernel since | 
|  | it stress tests request_module() and this will very likely cause | 
|  | some issues by taking over precious threads available from other | 
|  | module load requests, ultimately this could be fatal. | 
|  |  | 
|  | To run tests run: | 
|  |  | 
|  | tools/testing/selftests/kmod/kmod.sh --help | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_RUNTIME | 
|  | bool | 
|  |  | 
|  | config TEST_RUNTIME_MODULE | 
|  | bool | 
|  |  | 
|  | config TEST_KALLSYMS | 
|  | tristate "module kallsyms find_symbol() test" | 
|  | depends on m | 
|  | select TEST_RUNTIME | 
|  | select TEST_RUNTIME_MODULE | 
|  | select TEST_KALLSYMS_A | 
|  | select TEST_KALLSYMS_B | 
|  | select TEST_KALLSYMS_C | 
|  | select TEST_KALLSYMS_D | 
|  | help | 
|  | This allows us to stress test find_symbol() through the kallsyms | 
|  | used to place symbols on the kernel ELF kallsyms and modules kallsyms | 
|  | where we place kernel symbols such as exported symbols. | 
|  |  | 
|  | We have four test modules: | 
|  |  | 
|  | A: has KALLSYSMS_NUMSYMS exported symbols | 
|  | B: uses one of A's symbols | 
|  | C: adds KALLSYMS_SCALE_FACTOR * KALLSYSMS_NUMSYMS exported | 
|  | D: adds 2 * the symbols than C | 
|  |  | 
|  | We stress test find_symbol() through two means: | 
|  |  | 
|  | 1) Upon load of B it will trigger simplify_symbols() to look for the | 
|  | one symbol it uses from the module A with tons of symbols. This is an | 
|  | indirect way for us to have B call resolve_symbol_wait() upon module | 
|  | load. This will eventually call find_symbol() which will eventually | 
|  | try to find the symbols used with find_exported_symbol_in_section(). | 
|  | find_exported_symbol_in_section() uses bsearch() so a binary search | 
|  | for each symbol. Binary search will at worst be O(log(n)) so the | 
|  | larger TEST_MODULE_KALLSYSMS the worse the search. | 
|  |  | 
|  | 2) The selftests should load C first, before B. Upon B's load towards | 
|  | the end right before we call module B's init routine we get | 
|  | complete_formation() called on the module. That will first check | 
|  | for duplicate symbols with the call to verify_exported_symbols(). | 
|  | That is when we'll force iteration on module C's insane symbol list. | 
|  | Since it has 10 * KALLSYMS_NUMSYMS it means we can first test | 
|  | just loading B without C. The amount of time it takes to load C Vs | 
|  | B can give us an idea of the impact growth of the symbol space and | 
|  | give us projection. Module A only uses one symbol from B so to allow | 
|  | this scaling in module C to be proportional, if it used more symbols | 
|  | then the first test would be doing more and increasing just the | 
|  | search space would be slightly different. The last module, module D | 
|  | will just increase the search space by twice the number of symbols in | 
|  | C so to allow for full projects. | 
|  |  | 
|  | tools/testing/selftests/module/find_symbol.sh | 
|  |  | 
|  | The current defaults will incur a build delay of about 7 minutes | 
|  | on an x86_64 with only 8 cores. Enable this only if you want to | 
|  | stress test find_symbol() with thousands of symbols. At the same | 
|  | time this is also useful to test building modules with thousands of | 
|  | symbols, and if BTF is enabled this also stress tests adding BTF | 
|  | information for each module. Currently enabling many more symbols | 
|  | will segfault the build system. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | if TEST_KALLSYMS | 
|  |  | 
|  | config TEST_KALLSYMS_A | 
|  | tristate | 
|  | depends on m | 
|  |  | 
|  | config TEST_KALLSYMS_B | 
|  | tristate | 
|  | depends on m | 
|  |  | 
|  | config TEST_KALLSYMS_C | 
|  | tristate | 
|  | depends on m | 
|  |  | 
|  | config TEST_KALLSYMS_D | 
|  | tristate | 
|  | depends on m | 
|  |  | 
|  | choice | 
|  | prompt "Kallsym test range" | 
|  | default TEST_KALLSYMS_LARGE | 
|  | help | 
|  | Selecting something other than "Fast" will enable tests which slow | 
|  | down the build and may crash your build. | 
|  |  | 
|  | config TEST_KALLSYMS_FAST | 
|  | bool "Fast builds" | 
|  | help | 
|  | You won't really be testing kallsysms, so this just helps fast builds | 
|  | when allmodconfig is used.. | 
|  |  | 
|  | config TEST_KALLSYMS_LARGE | 
|  | bool "Enable testing kallsyms with large exports" | 
|  | help | 
|  | This will enable larger number of symbols. This will slow down | 
|  | your build considerably. | 
|  |  | 
|  | config TEST_KALLSYMS_MAX | 
|  | bool "Known kallsysms limits" | 
|  | help | 
|  | This will enable exports to the point we know we'll start crashing | 
|  | builds. | 
|  |  | 
|  | endchoice | 
|  |  | 
|  | config TEST_KALLSYMS_NUMSYMS | 
|  | int "test kallsyms number of symbols" | 
|  | range 2 10000 | 
|  | default 2 if TEST_KALLSYMS_FAST | 
|  | default 100 if TEST_KALLSYMS_LARGE | 
|  | default 10000 if TEST_KALLSYMS_MAX | 
|  | help | 
|  | The number of symbols to create on TEST_KALLSYMS_A, only one of which | 
|  | module TEST_KALLSYMS_B will use. This also will be used | 
|  | for how many symbols TEST_KALLSYMS_C will have, scaled up by | 
|  | TEST_KALLSYMS_SCALE_FACTOR. Note that setting this to 10,000 will | 
|  | trigger a segfault today, don't use anything close to it unless | 
|  | you are aware that this should not be used for automated build tests. | 
|  |  | 
|  | config TEST_KALLSYMS_SCALE_FACTOR | 
|  | int "test kallsyms scale factor" | 
|  | default 8 | 
|  | help | 
|  | How many more unusued symbols will TEST_KALLSYSMS_C have than | 
|  | TEST_KALLSYMS_A. If 8, then module C will have 8 * syms | 
|  | than module A. Then TEST_KALLSYMS_D will have double the amount | 
|  | of symbols than C so to allow projections. | 
|  |  | 
|  | endif # TEST_KALLSYMS | 
|  |  | 
|  | config TEST_DEBUG_VIRTUAL | 
|  | tristate "Test CONFIG_DEBUG_VIRTUAL feature" | 
|  | depends on DEBUG_VIRTUAL | 
|  | help | 
|  | Test the kernel's ability to detect incorrect calls to | 
|  | virt_to_phys() done against the non-linear part of the | 
|  | kernel's virtual address map. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_MEMCAT_P | 
|  | tristate "Test memcat_p() helper function" | 
|  | help | 
|  | Test the memcat_p() helper for correctly merging two | 
|  | pointer arrays together. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_OBJAGG | 
|  | tristate "Perform selftest on object aggreration manager" | 
|  | default n | 
|  | depends on OBJAGG | 
|  | help | 
|  | Enable this option to test object aggregation manager on boot | 
|  | (or module load). | 
|  |  | 
|  | config TEST_MEMINIT | 
|  | tristate "Test heap/page initialization" | 
|  | help | 
|  | Test if the kernel is zero-initializing heap and page allocations. | 
|  | This can be useful to test init_on_alloc and init_on_free features. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_HMM | 
|  | tristate "Test HMM (Heterogeneous Memory Management)" | 
|  | depends on TRANSPARENT_HUGEPAGE | 
|  | depends on DEVICE_PRIVATE | 
|  | select HMM_MIRROR | 
|  | select MMU_NOTIFIER | 
|  | help | 
|  | This is a pseudo device driver solely for testing HMM. | 
|  | Say M here if you want to build the HMM test module. | 
|  | Doing so will allow you to run tools/testing/selftest/vm/hmm-tests. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_FREE_PAGES | 
|  | tristate "Test freeing pages" | 
|  | help | 
|  | Test that a memory leak does not occur due to a race between | 
|  | freeing a block of pages and a speculative page reference. | 
|  | Loading this module is safe if your kernel has the bug fixed. | 
|  | If the bug is not fixed, it will leak gigabytes of memory and | 
|  | probably OOM your system. | 
|  |  | 
|  | config TEST_FPU | 
|  | tristate "Test floating point operations in kernel space" | 
|  | depends on ARCH_HAS_KERNEL_FPU_SUPPORT && !KCOV_INSTRUMENT_ALL | 
|  | help | 
|  | Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu | 
|  | which will trigger a sequence of floating point operations. This is used | 
|  | for self-testing floating point control register setting in | 
|  | kernel_fpu_begin(). | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_CLOCKSOURCE_WATCHDOG | 
|  | tristate "Test clocksource watchdog in kernel space" | 
|  | depends on CLOCKSOURCE_WATCHDOG | 
|  | help | 
|  | Enable this option to create a kernel module that will trigger | 
|  | a test of the clocksource watchdog.  This module may be loaded | 
|  | via modprobe or insmod in which case it will run upon being | 
|  | loaded, or it may be built in, in which case it will run | 
|  | shortly after boot. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_OBJPOOL | 
|  | tristate "Test module for correctness and stress of objpool" | 
|  | default n | 
|  | depends on m && DEBUG_KERNEL | 
|  | help | 
|  | This builds the "test_objpool" module that should be used for | 
|  | correctness verification and concurrent testings of objects | 
|  | allocation and reclamation. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config TEST_KEXEC_HANDOVER | 
|  | bool "Test for Kexec HandOver" | 
|  | default n | 
|  | depends on KEXEC_HANDOVER | 
|  | help | 
|  | This option enables test for Kexec HandOver (KHO). | 
|  | The test consists of two parts: saving kernel data before kexec and | 
|  | restoring the data after kexec and verifying that it was properly | 
|  | handed over. This test module creates and saves data on the boot of | 
|  | the first kernel and restores and verifies the data on the boot of | 
|  | kexec'ed kernel. | 
|  |  | 
|  | For detailed documentation about KHO, see Documentation/core-api/kho. | 
|  |  | 
|  | To run the test run: | 
|  |  | 
|  | tools/testing/selftests/kho/vmtest.sh -h | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config RATELIMIT_KUNIT_TEST | 
|  | tristate "KUnit Test for correctness and stress of ratelimit" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | This builds the "test_ratelimit" module that should be used | 
|  | for correctness verification and concurrent testings of rate | 
|  | limiting. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config INT_POW_KUNIT_TEST | 
|  | tristate "Integer exponentiation (int_pow) test" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | This option enables the KUnit test suite for the int_pow function, | 
|  | which performs integer exponentiation. The test suite is designed to | 
|  | verify that the implementation of int_pow correctly computes the power | 
|  | of a given base raised to a given exponent. | 
|  |  | 
|  | Enabling this option will include tests that check various scenarios | 
|  | and edge cases to ensure the accuracy and reliability of the exponentiation | 
|  | function. | 
|  |  | 
|  | If unsure, say N | 
|  |  | 
|  | config INT_SQRT_KUNIT_TEST | 
|  | tristate "Integer square root test" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | This option enables the KUnit test suite for the int_sqrt() function, | 
|  | which performs square root calculation. The test suite checks | 
|  | various scenarios, including edge cases, to ensure correctness. | 
|  |  | 
|  | Enabling this option will include tests that check various scenarios | 
|  | and edge cases to ensure the accuracy and reliability of the square root | 
|  | function. | 
|  |  | 
|  | If unsure, say N | 
|  |  | 
|  | config INT_LOG_KUNIT_TEST | 
|  | tristate "Integer log (int_log) test" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | This option enables the KUnit test suite for the int_log library, which | 
|  | provides two functions to compute the integer logarithm in base 2 and | 
|  | base 10, called respectively as intlog2 and intlog10. | 
|  |  | 
|  | If unsure, say N | 
|  |  | 
|  | config GCD_KUNIT_TEST | 
|  | tristate "Greatest common divisor test" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | This option enables the KUnit test suite for the gcd() function, | 
|  | which computes the greatest common divisor of two numbers. | 
|  |  | 
|  | This test suite verifies the correctness of gcd() across various | 
|  | scenarios, including edge cases. | 
|  |  | 
|  | If unsure, say N | 
|  |  | 
|  | config PRIME_NUMBERS_KUNIT_TEST | 
|  | tristate "Prime number generator test" if !KUNIT_ALL_TESTS | 
|  | depends on KUNIT | 
|  | depends on PRIME_NUMBERS | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | This option enables the KUnit test suite for the {is,next}_prime_number | 
|  | functions. | 
|  |  | 
|  | Enabling this option will include tests that compare the prime number | 
|  | generator functions against a brute force implementation. | 
|  |  | 
|  | If unsure, say N | 
|  |  | 
|  | endif # RUNTIME_TESTING_MENU | 
|  |  | 
|  | config ARCH_USE_MEMTEST | 
|  | bool | 
|  | help | 
|  | An architecture should select this when it uses early_memtest() | 
|  | during boot process. | 
|  |  | 
|  | config MEMTEST | 
|  | bool "Memtest" | 
|  | depends on ARCH_USE_MEMTEST | 
|  | help | 
|  | This option adds a kernel parameter 'memtest', which allows memtest | 
|  | to be set and executed. | 
|  | memtest=0, mean disabled; -- default | 
|  | memtest=1, mean do 1 test pattern; | 
|  | ... | 
|  | memtest=17, mean do 17 test patterns. | 
|  | If you are unsure how to answer this question, answer N. | 
|  |  | 
|  |  | 
|  |  | 
|  | config HYPERV_TESTING | 
|  | bool "Microsoft Hyper-V driver testing" | 
|  | default n | 
|  | depends on HYPERV && DEBUG_FS | 
|  | help | 
|  | Select this option to enable Hyper-V vmbus testing. | 
|  |  | 
|  | endmenu # "Kernel Testing and Coverage" | 
|  |  | 
|  | menu "Rust hacking" | 
|  |  | 
|  | config RUST_DEBUG_ASSERTIONS | 
|  | bool "Debug assertions" | 
|  | depends on RUST | 
|  | help | 
|  | Enables rustc's `-Cdebug-assertions` codegen option. | 
|  |  | 
|  | This flag lets you turn `cfg(debug_assertions)` conditional | 
|  | compilation on or off. This can be used to enable extra debugging | 
|  | code in development but not in production. For example, it controls | 
|  | the behavior of the standard library's `debug_assert!` macro. | 
|  |  | 
|  | Note that this will apply to all Rust code, including `core`. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config RUST_OVERFLOW_CHECKS | 
|  | bool "Overflow checks" | 
|  | default y | 
|  | depends on RUST | 
|  | help | 
|  | Enables rustc's `-Coverflow-checks` codegen option. | 
|  |  | 
|  | This flag allows you to control the behavior of runtime integer | 
|  | overflow. When overflow-checks are enabled, a Rust panic will occur | 
|  | on overflow. | 
|  |  | 
|  | Note that this will apply to all Rust code, including `core`. | 
|  |  | 
|  | If unsure, say Y. | 
|  |  | 
|  | config RUST_BUILD_ASSERT_ALLOW | 
|  | bool "Allow unoptimized build-time assertions" | 
|  | depends on RUST | 
|  | help | 
|  | Controls how `build_error!` and `build_assert!` are handled during the build. | 
|  |  | 
|  | If calls to them exist in the binary, it may indicate a violated invariant | 
|  | or that the optimizer failed to verify the invariant during compilation. | 
|  |  | 
|  | This should not happen, thus by default the build is aborted. However, | 
|  | as an escape hatch, you can choose Y here to ignore them during build | 
|  | and let the check be carried at runtime (with `panic!` being called if | 
|  | the check fails). | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | config RUST_KERNEL_DOCTESTS | 
|  | bool "Doctests for the `kernel` crate" if !KUNIT_ALL_TESTS | 
|  | depends on RUST && KUNIT=y | 
|  | default KUNIT_ALL_TESTS | 
|  | help | 
|  | This builds the documentation tests of the `kernel` crate | 
|  | as KUnit tests. | 
|  |  | 
|  | For more information on KUnit and unit tests in general, | 
|  | please refer to the KUnit documentation in Documentation/dev-tools/kunit/. | 
|  |  | 
|  | If unsure, say N. | 
|  |  | 
|  | endmenu # "Rust" | 
|  |  | 
|  | endmenu # Kernel hacking |