Kconfig.debug

# 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 PRINTK_EXECUTION_CTX
	bool
	depends on PRINTK
	help
	  This option extends struct printk_info to include extra execution
	  context in printk, such as task name and CPU number from where the
	  message originated. This is useful for correlating printk messages
	  with specific execution contexts.

	  This is automatically enabled when a console driver that supports
	  execution context is selected.

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.

config DEBUG_BUGVERBOSE_DETAILED
	bool "Verbose WARN_ON_ONCE() reporting (adds 100K)" if DEBUG_BUGVERBOSE
	help
	  Say Y here to make WARN_ON_ONCE() output the condition string of the
	  warning, in addition to the file name and line number.
	  This helps debugging, but costs about 100K of memory.

	  Say N if unsure.


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 || (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.

	  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 >= 122
	# 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 v1.22 or later, which will convert
	  DWARF type info into equivalent deduplicated BTF type info.

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 PAHOLE_HAS_INLINE
	def_bool PAHOLE_VERSION >= 132
	help
	  Support for the "inline" BTF feature is available. It encodes
	  information about inline sites and how to retrieve their parameters.

config DEBUG_INFO_BTF_MODULES
	bool "Generate BTF type information for kernel modules"
	default y
	depends on DEBUG_INFO_BTF && MODULES
	help
	  Generate compact split BTF type information for kernel modules.

config DEBUG_INFO_BTF_INLINE
	tristate "Provide information about inline sites in BTF"
	default n
	depends on DEBUG_INFO_BTF && PAHOLE_HAS_INLINE && SYSFS
	select DEBUG_INFO_BTF_MODULES if MODULES
	help
	  Generate information about inline sites in .BTF.inline sections.
	  These sections contain split BTF relative to the kernel or module BTF
	  and are made available in /sys/kernel/btf with a ".inline" suffix.
	  The information describes inline locations and how to retrieve their
	  associated parameters.

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 !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. 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,
	  __initdata, and so on (see the full list in include/linux/init.h).
	  This directs the toolchain to place code/data in specific sections.

	  The section mismatch analysis is always performed after a full
	  kernel build, and enabling this option causes the option
	  -fno-inline-functions-called-once to be added to gcc commands.

	  However, 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 WARN_CONTEXT_ANALYSIS
	bool "Compiler context-analysis warnings"
	depends on CC_IS_CLANG && CLANG_VERSION >= 230000
	# Branch profiling re-defines "if", which messes with the compiler's
	# ability to analyze __cond_acquires(..), resulting in false positives.
	depends on !TRACE_BRANCH_PROFILING
	default y
	help
	  Context Analysis is a language extension, which enables statically
	  checking that required contexts are active (or inactive) by acquiring
	  and releasing user-definable "context locks".

	  Clang's name of the feature is "Thread Safety Analysis". Requires
	  Clang 23 or later.

	  Produces warnings by default. Select CONFIG_WERROR if you wish to
	  turn these warnings into errors.

	  For more details, see Documentation/dev-tools/context-analysis.rst.

config WARN_CONTEXT_ANALYSIS_ALL
	bool "Enable context analysis for all source files"
	depends on WARN_CONTEXT_ANALYSIS
	depends on EXPERT && !COMPILE_TEST
	help
	  Enable tree-wide context analysis. This is likely to produce a
	  large number of false positives - enable at your own risk.

	  If unsure, say N.

endmenu # "Compiler options"

menu "Generic Kernel Debugging Instruments"

config MAGIC_SYSRQ
	bool "Magic SysRq key"
	depends on !UML || MCONSOLE
	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. On UML,
	  this is accomplished by sending a "sysrq" command with mconsole,
	  followed by the letter for the requested command. 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,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_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 PREEMPT_COUNT || !DEFERRED_STRUCT_PAGE_INIT
	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.