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lib/Kconfig.debug 70 KB
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  # SPDX-License-Identifier: GPL-2.0-only
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  menu "Kernel hacking"
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  menu "printk and dmesg options"
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  config PRINTK_TIME
  	bool "Show timing information on printks"
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  	depends on PRINTK
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  	help
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  	  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
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  	  parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
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  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.
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  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.
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  	  Note: This does not affect the log level of un-prefixed printk()
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  	  usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
  	  option.
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  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>"
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  config MESSAGE_LOGLEVEL_DEFAULT
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  	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.
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  	  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.
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  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 jiffie" 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
  	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. Thus, the debugfs
  	  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
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  	  See Documentation/admin-guide/dynamic-debug-howto.rst for additional
  	  information.
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  endmenu # "printk and dmesg options"
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  menu "Compile-time checks and compiler options"
  
  config DEBUG_INFO
  	bool "Compile the kernel with debug info"
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  	depends on DEBUG_KERNEL && !COMPILE_TEST
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  	help
            If you say Y here the resulting kernel image 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.
  	  Say Y here only if you plan to debug the kernel.
  
  	  If unsure, say N.
  
  config DEBUG_INFO_REDUCED
  	bool "Reduce debugging information"
  	depends on DEBUG_INFO
  	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.
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  config DEBUG_INFO_SPLIT
  	bool "Produce split debuginfo in .dwo files"
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  	depends on DEBUG_INFO
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  	depends on $(cc-option,-gsplit-dwarf)
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  	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.
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  config DEBUG_INFO_DWARF4
  	bool "Generate dwarf4 debuginfo"
  	depends on DEBUG_INFO
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  	depends on $(cc-option,-gdwarf-4)
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  	help
  	  Generate dwarf4 debug info. This requires recent versions
  	  of gcc and gdb. It makes the debug information larger.
  	  But it significantly improves the success of resolving
  	  variables in gdb on optimized code.
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  config DEBUG_INFO_BTF
  	bool "Generate BTF typeinfo"
  	depends on DEBUG_INFO
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  	depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
  	depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
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  	help
  	  Generate deduplicated BTF type information from DWARF debug info.
  	  Turning this on expects presence of pahole tool, which will convert
  	  DWARF type info into equivalent deduplicated BTF type info.
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  config GDB_SCRIPTS
  	bool "Provide GDB scripts for kernel debugging"
  	depends on DEBUG_INFO
  	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
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  	  instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
  	  for further details.
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  config ENABLE_MUST_CHECK
  	bool "Enable __must_check logic"
  	default y
  	help
  	  Enable the __must_check logic in the kernel build.  Disable this to
  	  suppress the "warning: ignoring return value of 'foo', declared with
  	  attribute warn_unused_result" messages.
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  config FRAME_WARN
  	int "Warn for stack frames larger than (needs gcc 4.4)"
  	range 0 8192
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  	default 2048 if GCC_PLUGIN_LATENT_ENTROPY
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  	default 1280 if (!64BIT && PARISC)
  	default 1024 if (!64BIT && !PARISC)
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  	default 2048 if 64BIT
  	help
  	  Tell gcc 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.
  	  Requires gcc 4.4
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  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.
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  config READABLE_ASM
          bool "Generate readable assembler code"
          depends on DEBUG_KERNEL
          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.
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  config DEBUG_FS
  	bool "Debug Filesystem"
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  	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.
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  	  For detailed documentation on the debugfs API, see
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  	  Documentation/filesystems/.
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  	  If unsure, say N.
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  config HEADERS_INSTALL
  	bool "Install uapi headers to usr/include"
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  	depends on !UML
  	help
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  	  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.
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  config OPTIMIZE_INLINING
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  	def_bool y
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  	help
  	  This option determines if the kernel forces gcc to inline the functions
  	  developers have marked 'inline'. Doing so takes away freedom from gcc to
  	  do what it thinks is best, which is desirable for the gcc 3.x series of
  	  compilers. The gcc 4.x series have a rewritten inlining algorithm and
  	  enabling this option will generate a smaller kernel there. Hopefully
  	  this algorithm is so good that allowing gcc 4.x and above to make the
  	  decision will become the default in the future. Until then this option
  	  is there to test gcc for this.
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  config DEBUG_SECTION_MISMATCH
  	bool "Enable full Section mismatch analysis"
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  	help
  	  The section mismatch analysis checks if there are illegal
  	  references from one section to another section.
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  	  During linktime or runtime, some sections are dropped;
  	  any use of code/data previously in these sections would
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  	  most likely result in an oops.
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  	  In the code, functions and variables are annotated with
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  	  __init,, etc. (see the full list in include/linux/init.h),
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  	  which results in the code/data being placed in specific sections.
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  	  The section mismatch analysis is always performed after a full
  	  kernel build, and enabling this option causes the following
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  	  additional step to occur:
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  	  - 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
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  	    the analysis would not catch the illegal reference.
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  	    This option tells gcc to inline less (but it does result in
  	    a larger kernel).
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  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.
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  #
  # 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
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  config FRAME_POINTER
  	bool "Compile the kernel with frame pointers"
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  	depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
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  	default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
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  	help
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  	  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)
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  config STACK_VALIDATION
  	bool "Compile-time stack metadata validation"
  	depends on HAVE_STACK_VALIDATION
  	default n
  	help
  	  Add compile-time checks to validate stack metadata, including frame
  	  pointers (if CONFIG_FRAME_POINTER is enabled).  This helps ensure
  	  that runtime stack traces are more reliable.
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  	  This is also a prerequisite for generation of ORC unwind data, which
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  	  is needed for CONFIG_UNWINDER_ORC.
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  	  For more information, see
  	  tools/objtool/Documentation/stack-validation.txt.
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  config DEBUG_FORCE_WEAK_PER_CPU
  	bool "Force weak per-cpu definitions"
  	depends on DEBUG_KERNEL
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  	help
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  	  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.
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  	  1. percpu symbols must be unique whether static or not
  	  2. percpu variables can't be defined inside a function
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  	  To ensure that generic code follows the above rules, this
  	  option forces all percpu variables to be defined as weak.
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  endmenu # "Compiler options"
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  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
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  	  keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
  	  Don't say Y unless you really know what this hack does.
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385

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  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
f8998c226   Hans Holmberg   lib/Kconfig.debug...
393
  	  to a bitmask as described in Documentation/admin-guide/sysrq.rst.
8eaede49d   Ben Hutchings   sysrq: Allow magi...
394

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  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.
f346f4b37   Adrian Bunk   [PATCH] let MAGIC...
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  config DEBUG_KERNEL
  	bool "Kernel debugging"
fef2c9bc1   Don Zickus   kernel/watchdog.c...
406
  	help
f346f4b37   Adrian Bunk   [PATCH] let MAGIC...
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  	  Say Y here if you are developing drivers or trying to debug and
  	  identify kernel problems.
fef2c9bc1   Don Zickus   kernel/watchdog.c...
409

c66d7a27b   Sinan Kaya   init: introduce D...
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  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.
0610c8a8a   Dave Hansen   order memory debu...
417
  menu "Memory Debugging"
fef2c9bc1   Don Zickus   kernel/watchdog.c...
418

8636a1f96   Masahiro Yamada   treewide: surroun...
419
  source "mm/Kconfig.debug"
fef2c9bc1   Don Zickus   kernel/watchdog.c...
420

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  config DEBUG_OBJECTS
  	bool "Debug object operations"
  	depends on DEBUG_KERNEL
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  	help
0610c8a8a   Dave Hansen   order memory debu...
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  	  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.
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428

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  config DEBUG_OBJECTS_SELFTEST
  	bool "Debug objects selftest"
  	depends on DEBUG_OBJECTS
  	help
  	  This enables the selftest of the object debug code.
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434

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  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.
3ac7fe5a4   Thomas Gleixner   infrastructure to...
443

c6f3a97f8   Thomas Gleixner   debugobjects: add...
444
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  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.
dc186ad74   Thomas Gleixner   workqueue: Add de...
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  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.
551d55a94   Mathieu Desnoyers   tree/tiny rcu: Ad...
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  config DEBUG_OBJECTS_RCU_HEAD
  	bool "Debug RCU callbacks objects"
fc2ecf7ec   Mathieu Desnoyers   rcu: Enable DEBUG...
460
  	depends on DEBUG_OBJECTS
551d55a94   Mathieu Desnoyers   tree/tiny rcu: Ad...
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  	help
  	  Enable this to turn on debugging of RCU list heads (call_rcu() usage).
e2852ae82   Tejun Heo   percpu_counter: a...
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  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.
3ae702054   Ingo Molnar   debugobjects: add...
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  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
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
477
  config DEBUG_SLAB
4a2f0acf0   Andrew Morton   [PATCH] kconfig: ...
478
  	bool "Debug slab memory allocations"
4675ff05d   Levin, Alexander (Sasha Levin)   kmemcheck: rip it...
479
  	depends on DEBUG_KERNEL && SLAB
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
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  	help
  	  Say Y here to have the kernel do limited verification on memory
  	  allocation as well as poisoning memory on free to catch use of freed
  	  memory. This can make kmalloc/kfree-intensive workloads much slower.
f0630fff5   Christoph Lameter   SLUB: support slu...
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  config SLUB_DEBUG_ON
  	bool "SLUB debugging on by default"
4675ff05d   Levin, Alexander (Sasha Levin)   kmemcheck: rip it...
486
  	depends on SLUB && SLUB_DEBUG
f0630fff5   Christoph Lameter   SLUB: support slu...
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  	default n
  	help
  	  Boot with debugging on by default. SLUB boots by default with
  	  the runtime debug capabilities switched off. Enabling this is
  	  equivalent to specifying the "slub_debug" parameter on boot.
  	  There is no support for more fine grained debug control like
  	  possible with slub_debug=xxx. SLUB debugging may be switched
  	  off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
  	  "slub_debug=-".
8ff12cfc0   Christoph Lameter   SLUB: Support for...
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  config SLUB_STATS
  	default n
  	bool "Enable SLUB performance statistics"
ab4d5ed5e   Christoph Lameter   slub: Enable sysf...
499
  	depends on SLUB && SYSFS
8ff12cfc0   Christoph Lameter   SLUB: Support for...
500
501
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  	help
  	  SLUB statistics are useful to debug SLUBs allocation behavior in
  	  order find ways to optimize the allocator. This should never be
  	  enabled for production use since keeping statistics slows down
  	  the allocator by a few percentage points. The slabinfo command
  	  supports the determination of the most active slabs to figure
  	  out which slabs are relevant to a particular load.
  	  Try running: slabinfo -DA
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  config HAVE_DEBUG_KMEMLEAK
  	bool
3bba00d7b   Catalin Marinas   kmemleak: Enable ...
510
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  config DEBUG_KMEMLEAK
  	bool "Kernel memory leak detector"
525c1f920   Kees Cook   lib: remove depen...
512
  	depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
79e0d9bd2   Catalin Marinas   kmemleak: Select ...
513
  	select DEBUG_FS
3bba00d7b   Catalin Marinas   kmemleak: Enable ...
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  	select STACKTRACE if STACKTRACE_SUPPORT
  	select KALLSYMS
b60e26a2f   Randy Dunlap   kmemleak: fix kco...
516
  	select CRC32
3bba00d7b   Catalin Marinas   kmemleak: Enable ...
517
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  	help
  	  Say Y here if you want to enable the memory leak
  	  detector. The memory allocation/freeing is traced in a way
  	  similar to the Boehm's conservative garbage collector, the
  	  difference being that the orphan objects are not freed but
  	  only shown in /sys/kernel/debug/kmemleak. Enabling this
  	  feature will introduce an overhead to memory
700199b0c   Andreas Platschek   Kconfig: lib/Kcon...
524
  	  allocations. See Documentation/dev-tools/kmemleak.rst for more
3bba00d7b   Catalin Marinas   kmemleak: Enable ...
525
  	  details.
0610c8a8a   Dave Hansen   order memory debu...
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  	  Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
  	  of finding leaks due to the slab objects poisoning.
  
  	  In order to access the kmemleak file, debugfs needs to be
  	  mounted (usually at /sys/kernel/debug).
c56658681   Catalin Marinas   mm: kmemleak: use...
531
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  config DEBUG_KMEMLEAK_MEM_POOL_SIZE
  	int "Kmemleak memory pool size"
0610c8a8a   Dave Hansen   order memory debu...
533
  	depends on DEBUG_KMEMLEAK
c59180ae3   Qian Cai   mm/kmemleak: incr...
534
  	range 200 1000000
b751c52bb   Nicolas Boichat   kmemleak: increas...
535
  	default 16000
0610c8a8a   Dave Hansen   order memory debu...
536
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  	help
  	  Kmemleak must track all the memory allocations to avoid
  	  reporting false positives. Since memory may be allocated or
c56658681   Catalin Marinas   mm: kmemleak: use...
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  	  freed before kmemleak is fully initialised, use a static pool
  	  of metadata objects to track such callbacks. After kmemleak is
  	  fully initialised, this memory pool acts as an emergency one
  	  if slab allocations fail.
0610c8a8a   Dave Hansen   order memory debu...
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  config DEBUG_KMEMLEAK_TEST
  	tristate "Simple test for the kernel memory leak detector"
  	depends on DEBUG_KMEMLEAK && m
  	help
  	  This option enables a module that explicitly leaks memory.
  
  	  If unsure, say N.
  
  config DEBUG_KMEMLEAK_DEFAULT_OFF
  	bool "Default kmemleak to off"
  	depends on DEBUG_KMEMLEAK
  	help
  	  Say Y here to disable kmemleak by default. It can then be enabled
  	  on the command line via kmemleak=on.
d53ce0422   Sri Krishna chowdary   kmemleak: add con...
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  config DEBUG_KMEMLEAK_AUTO_SCAN
  	bool "Enable kmemleak auto scan thread on boot up"
  	default y
  	depends on DEBUG_KMEMLEAK
  	help
  	  Depending on the cpu, kmemleak scan may be cpu intensive and can
  	  stall user tasks at times. This option enables/disables automatic
  	  kmemleak scan at boot up.
  
  	  Say N here to disable kmemleak auto scan thread to stop automatic
  	  scanning. Disabling this option disables automatic reporting of
  	  memory leaks.
  
  	  If unsure, say Y.
0610c8a8a   Dave Hansen   order memory debu...
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  config DEBUG_STACK_USAGE
  	bool "Stack utilization instrumentation"
6c31da346   Helge Deller   parisc,metag: Imp...
574
  	depends on DEBUG_KERNEL && !IA64
0610c8a8a   Dave Hansen   order memory debu...
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  	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.
  
  	  This option will slow down process creation somewhat.
  
  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.
4f115147f   Davidlohr Bueso   mm,vmacache: add ...
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  config DEBUG_VM_VMACACHE
  	bool "Debug VMA caching"
  	depends on DEBUG_VM
  	help
  	  Enable this to turn on VMA caching debug information. Doing so
  	  can cause significant overhead, so only enable it in non-production
  	  environments.
  
  	  If unsure, say N.
0610c8a8a   Dave Hansen   order memory debu...
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  config DEBUG_VM_RB
  	bool "Debug VM red-black trees"
  	depends on DEBUG_VM
  	help
a663dad65   Davidlohr Bueso   mm: fix CONFIG_DE...
602
  	  Enable VM red-black tree debugging information and extra validations.
0610c8a8a   Dave Hansen   order memory debu...
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604
  
  	  If unsure, say N.
95ad97554   Kirill A. Shutemov   page-flags: intro...
605
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  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.
fa5b6ec9e   Laura Abbott   lib/Kconfig.debug...
612
613
  config ARCH_HAS_DEBUG_VIRTUAL
  	bool
0610c8a8a   Dave Hansen   order memory debu...
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  config DEBUG_VIRTUAL
  	bool "Debug VM translations"
fa5b6ec9e   Laura Abbott   lib/Kconfig.debug...
616
  	depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
0610c8a8a   Dave Hansen   order memory debu...
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  	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_SPARSE && 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_HIGHMEM
  	bool "Highmem debugging"
  	depends on DEBUG_KERNEL && HIGHMEM
  	help
b1357c9f6   Geert Uytterhoeven   Kconfig.debug: Gr...
680
681
  	  This option enables additional error checking for high memory
  	  systems.  Disable for production systems.
0610c8a8a   Dave Hansen   order memory debu...
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685
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688
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  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
edb0ec072   Borislav Petkov   kexec, Kconfig: s...
691
  	  and exception stacks (if your architecture uses them). This
0610c8a8a   Dave Hansen   order memory debu...
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  	  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".
0b24becc8   Andrey Ryabinin   kasan: add kernel...
703
  source "lib/Kconfig.kasan"
0610c8a8a   Dave Hansen   order memory debu...
704
  endmenu # "Memory Debugging"
5c9a8750a   Dmitry Vyukov   kernel: add kcov ...
705
706
707
  config ARCH_HAS_KCOV
  	bool
  	help
40453c4f9   Mark Rutland   kcov: improve CON...
708
709
710
  	  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.
5c9a8750a   Dmitry Vyukov   kernel: add kcov ...
711

5aadfdeb8   Masahiro Yamada   kcov: test compil...
712
713
  config CC_HAS_SANCOV_TRACE_PC
  	def_bool $(cc-option,-fsanitize-coverage=trace-pc)
5c9a8750a   Dmitry Vyukov   kernel: add kcov ...
714
715
716
  config KCOV
  	bool "Code coverage for fuzzing"
  	depends on ARCH_HAS_KCOV
5aadfdeb8   Masahiro Yamada   kcov: test compil...
717
  	depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
5c9a8750a   Dmitry Vyukov   kernel: add kcov ...
718
  	select DEBUG_FS
5aadfdeb8   Masahiro Yamada   kcov: test compil...
719
  	select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
5c9a8750a   Dmitry Vyukov   kernel: add kcov ...
720
721
722
723
724
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726
  	help
  	  KCOV exposes kernel code coverage information in a form suitable
  	  for coverage-guided fuzzing (randomized testing).
  
  	  If RANDOMIZE_BASE is enabled, PC values will not be stable across
  	  different machines and across reboots. If you need stable PC values,
  	  disable RANDOMIZE_BASE.
700199b0c   Andreas Platschek   Kconfig: lib/Kcon...
727
  	  For more details, see Documentation/dev-tools/kcov.rst.
5c9a8750a   Dmitry Vyukov   kernel: add kcov ...
728

d677a4d60   Victor Chibotaru   Makefile: support...
729
730
731
  config KCOV_ENABLE_COMPARISONS
  	bool "Enable comparison operands collection by KCOV"
  	depends on KCOV
5aadfdeb8   Masahiro Yamada   kcov: test compil...
732
  	depends on $(cc-option,-fsanitize-coverage=trace-cmp)
d677a4d60   Victor Chibotaru   Makefile: support...
733
734
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736
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  	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.
a4691deab   Vegard Nossum   kcov: allow more ...
738
739
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  config KCOV_INSTRUMENT_ALL
  	bool "Instrument all code by default"
  	depends on KCOV
5aadfdeb8   Masahiro Yamada   kcov: test compil...
741
  	default y
a4691deab   Vegard Nossum   kcov: allow more ...
742
743
744
745
746
747
  	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.
a304e1b82   David Woodhouse   [PATCH] Debug sha...
748
749
  config DEBUG_SHIRQ
  	bool "Debug shared IRQ handlers"
0244ad004   Martin Schwidefsky   Remove GENERIC_HA...
750
  	depends on DEBUG_KERNEL
a304e1b82   David Woodhouse   [PATCH] Debug sha...
751
752
753
754
755
  	help
  	  Enable this to generate a spurious interrupt as soon as a shared
  	  interrupt handler is registered, and just before one is deregistered.
  	  Drivers ought to be able to handle interrupts coming in at those
  	  points; some don't and need to be caught.
92aef8fba   Dave Hansen   hang and lockup d...
756
  menu "Debug Lockups and Hangs"
58687acba   Don Zickus   lockup_detector: ...
757
  config LOCKUP_DETECTOR
05a4a9527   Nicholas Piggin   kernel/watchdog: ...
758
759
760
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  	bool
  
  config SOFTLOCKUP_DETECTOR
  	bool "Detect Soft Lockups"
dea20a3fb   Heiko Carstens   [PATCH] Disable D...
762
  	depends on DEBUG_KERNEL && !S390
05a4a9527   Nicholas Piggin   kernel/watchdog: ...
763
  	select LOCKUP_DETECTOR
8446f1d39   Ingo Molnar   [PATCH] detect so...
764
  	help
58687acba   Don Zickus   lockup_detector: ...
765
  	  Say Y here to enable the kernel to act as a watchdog to detect
05a4a9527   Nicholas Piggin   kernel/watchdog: ...
766
  	  soft lockups.
58687acba   Don Zickus   lockup_detector: ...
767
768
  
  	  Softlockups are bugs that cause the kernel to loop in kernel
5f3290894   Fernando Luis Vázquez Cao   watchdog: Update ...
769
  	  mode for more than 20 seconds, without giving other tasks a
58687acba   Don Zickus   lockup_detector: ...
770
771
  	  chance to run.  The current stack trace is displayed upon
  	  detection and the system will stay locked up.
8446f1d39   Ingo Molnar   [PATCH] detect so...
772

5f00ae0d3   Randy Dunlap   lib/Kconfig.debug...
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792
793
794
795
  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 BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
  	int
  	depends on SOFTLOCKUP_DETECTOR
  	range 0 1
  	default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
  	default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
05a4a9527   Nicholas Piggin   kernel/watchdog: ...
796
797
798
799
800
  config HARDLOCKUP_DETECTOR_PERF
  	bool
  	select SOFTLOCKUP_DETECTOR
  
  #
7edaeb684   Thomas Gleixner   kernel/watchdog: ...
801
802
803
804
805
806
807
  # 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
  
  #
05a4a9527   Nicholas Piggin   kernel/watchdog: ...
808
809
810
811
812
813
814
815
816
817
818
819
820
  # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
  # lockup detector rather than the perf based detector.
  #
  config HARDLOCKUP_DETECTOR
  	bool "Detect Hard Lockups"
  	depends on DEBUG_KERNEL && !S390
  	depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
  	select LOCKUP_DETECTOR
  	select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
  	select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH
  	help
  	  Say Y here to enable the kernel to act as a watchdog to detect
  	  hard lockups.
58687acba   Don Zickus   lockup_detector: ...
821
  	  Hardlockups are bugs that cause the CPU to loop in kernel mode
5f3290894   Fernando Luis Vázquez Cao   watchdog: Update ...
822
  	  for more than 10 seconds, without letting other interrupts have a
58687acba   Don Zickus   lockup_detector: ...
823
824
  	  chance to run.  The current stack trace is displayed upon detection
  	  and the system will stay locked up.
8446f1d39   Ingo Molnar   [PATCH] detect so...
825

fef2c9bc1   Don Zickus   kernel/watchdog.c...
826
827
  config BOOTPARAM_HARDLOCKUP_PANIC
  	bool "Panic (Reboot) On Hard Lockups"
8f1f66ed7   Jan Beulich   lib/Kconfig.debug...
828
  	depends on HARDLOCKUP_DETECTOR
fef2c9bc1   Don Zickus   kernel/watchdog.c...
829
830
831
  	help
  	  Say Y here to enable the kernel to panic on "hard lockups",
  	  which are bugs that cause the kernel to loop in kernel
5f3290894   Fernando Luis Vázquez Cao   watchdog: Update ...
832
833
  	  mode with interrupts disabled for more than 10 seconds (configurable
  	  using the watchdog_thresh sysctl).
fef2c9bc1   Don Zickus   kernel/watchdog.c...
834
835
836
837
838
  
  	  Say N if unsure.
  
  config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
  	int
8f1f66ed7   Jan Beulich   lib/Kconfig.debug...
839
  	depends on HARDLOCKUP_DETECTOR
fef2c9bc1   Don Zickus   kernel/watchdog.c...
840
841
842
  	range 0 1
  	default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
  	default 1 if BOOTPARAM_HARDLOCKUP_PANIC
e162b39a3   Mandeep Singh Baines   softlockup: decou...
843
844
845
  config DETECT_HUNG_TASK
  	bool "Detect Hung Tasks"
  	depends on DEBUG_KERNEL
05a4a9527   Nicholas Piggin   kernel/watchdog: ...
846
  	default SOFTLOCKUP_DETECTOR
e162b39a3   Mandeep Singh Baines   softlockup: decou...
847
  	help
0610c8a8a   Dave Hansen   order memory debu...
848
849
  	  Say Y here to enable the kernel to detect "hung tasks",
  	  which are bugs that cause the task to be stuck in
96b03ab86   Vivien Didelot   locking/hung_task...
850
  	  uninterruptible "D" state indefinitely.
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
851

0610c8a8a   Dave Hansen   order memory debu...
852
853
854
855
856
  	  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.
871751e25   Al Viro   [PATCH] slab: imp...
857

0610c8a8a   Dave Hansen   order memory debu...
858
859
860
861
  config DEFAULT_HUNG_TASK_TIMEOUT
  	int "Default timeout for hung task detection (in seconds)"
  	depends on DETECT_HUNG_TASK
  	default 120
f0630fff5   Christoph Lameter   SLUB: support slu...
862
  	help
0610c8a8a   Dave Hansen   order memory debu...
863
864
865
  	  This option controls the default timeout (in seconds) used
  	  to determine when a task has become non-responsive and should
  	  be considered hung.
f0630fff5   Christoph Lameter   SLUB: support slu...
866

0610c8a8a   Dave Hansen   order memory debu...
867
868
869
  	  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.
8ff12cfc0   Christoph Lameter   SLUB: Support for...
870

0610c8a8a   Dave Hansen   order memory debu...
871
872
  	  A timeout of 0 disables the check.  The default is two minutes.
  	  Keeping the default should be fine in most cases.
b69ec42b1   Catalin Marinas   Kconfig: clean up...
873

0610c8a8a   Dave Hansen   order memory debu...
874
875
876
  config BOOTPARAM_HUNG_TASK_PANIC
  	bool "Panic (Reboot) On Hung Tasks"
  	depends on DETECT_HUNG_TASK
3bba00d7b   Catalin Marinas   kmemleak: Enable ...
877
  	help
0610c8a8a   Dave Hansen   order memory debu...
878
879
880
  	  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.
3bba00d7b   Catalin Marinas   kmemleak: Enable ...
881

0610c8a8a   Dave Hansen   order memory debu...
882
883
884
885
886
  	  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.
bf96d1e3e   Catalin Marinas   kmemleak: Do not ...
887

0610c8a8a   Dave Hansen   order memory debu...
888
  	  Say N if unsure.
bf96d1e3e   Catalin Marinas   kmemleak: Do not ...
889

0610c8a8a   Dave Hansen   order memory debu...
890
891
892
893
894
895
  config BOOTPARAM_HUNG_TASK_PANIC_VALUE
  	int
  	depends on DETECT_HUNG_TASK
  	range 0 1
  	default 0 if !BOOTPARAM_HUNG_TASK_PANIC
  	default 1 if BOOTPARAM_HUNG_TASK_PANIC
3bba00d7b   Catalin Marinas   kmemleak: Enable ...
896

82607adcf   Tejun Heo   workqueue: implem...
897
898
899
900
901
902
903
904
905
906
  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.
92aef8fba   Dave Hansen   hang and lockup d...
907
908
909
910
  endmenu # "Debug lockups and hangs"
  
  config PANIC_ON_OOPS
  	bool "Panic on Oops"
a9d9058ab   Catalin Marinas   kmemleak: Allow t...
911
  	help
92aef8fba   Dave Hansen   hang and lockup d...
912
913
914
  	  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.
a9d9058ab   Catalin Marinas   kmemleak: Allow t...
915

92aef8fba   Dave Hansen   hang and lockup d...
916
917
918
919
920
921
922
923
924
925
926
  	  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
5800dc3cf   Jason Baron   panic: Make panic...
927
928
929
930
931
932
933
934
  config PANIC_TIMEOUT
  	int "panic timeout"
  	default 0
  	help
  	  Set the timeout value (in seconds) until a reboot occurs when the
  	  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.
0610c8a8a   Dave Hansen   order memory debu...
935
936
937
938
  config SCHED_DEBUG
  	bool "Collect scheduler debugging info"
  	depends on DEBUG_KERNEL && PROC_FS
  	default y
0822ee4ac   Catalin Marinas   kmemleak: Simple ...
939
  	help
0610c8a8a   Dave Hansen   order memory debu...
940
941
942
  	  If you say Y here, the /proc/sched_debug file will be provided
  	  that can help debug the scheduler. The runtime overhead of this
  	  option is minimal.
0822ee4ac   Catalin Marinas   kmemleak: Simple ...
943

f6db83479   Naveen N. Rao   sched/stat: Simpl...
944
945
946
  config SCHED_INFO
  	bool
  	default n
0610c8a8a   Dave Hansen   order memory debu...
947
948
949
  config SCHEDSTATS
  	bool "Collect scheduler statistics"
  	depends on DEBUG_KERNEL && PROC_FS
f6db83479   Naveen N. Rao   sched/stat: Simpl...
950
  	select SCHED_INFO
0610c8a8a   Dave Hansen   order memory debu...
951
952
953
954
955
956
957
958
  	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.
0822ee4ac   Catalin Marinas   kmemleak: Simple ...
959

0d9e26329   Aaron Tomlin   sched: Add defaul...
960
961
962
963
964
965
966
967
968
969
970
  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.
3c17ad19f   John Stultz   timekeeping: Add ...
971
972
973
974
975
976
977
978
979
980
981
982
  config DEBUG_TIMEKEEPING
  	bool "Enable extra timekeeping sanity checking"
  	help
  	  This option will enable additional timekeeping sanity checks
  	  which may be helpful when diagnosing issues where timekeeping
  	  problems are suspected.
  
  	  This may include checks in the timekeeping hotpaths, so this
  	  option may have a (very small) performance impact to some
  	  workloads.
  
  	  If unsure, say N.
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
983
984
  config DEBUG_PREEMPT
  	bool "Debug preemptible kernel"
01deab98e   Kumar Gala   powerpc: Minor cl...
985
  	depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
986
987
988
989
990
991
  	default y
  	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.
9eade16b4   Dave Hansen   group locking deb...
992
  menu "Lock Debugging (spinlocks, mutexes, etc...)"
f07cbebb6   Waiman Long   locking/Kconfig: ...
993
994
995
996
  config LOCK_DEBUGGING_SUPPORT
  	bool
  	depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  	default y
19193bcad   Waiman Long   locking/Kconfig: ...
997
998
999
1000
1001
1002
1003
  config PROVE_LOCKING
  	bool "Lock debugging: prove locking correctness"
  	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
  	select LOCKDEP
  	select DEBUG_SPINLOCK
  	select DEBUG_MUTEXES
  	select DEBUG_RT_MUTEXES if RT_MUTEXES
c71fd893f   Waiman Long   locking/rwsem: Ma...
1004
  	select DEBUG_RWSEMS
19193bcad   Waiman Long   locking/Kconfig: ...
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
  	select DEBUG_WW_MUTEX_SLOWPATH
  	select DEBUG_LOCK_ALLOC
  	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.
387b14684   Mauro Carvalho Chehab   docs: locking: co...
1040
  	 For more details, see Documentation/locking/lockdep-design.rst.
19193bcad   Waiman Long   locking/Kconfig: ...
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
  
  config LOCK_STAT
  	bool "Lock usage statistics"
  	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
  	select LOCKDEP
  	select DEBUG_SPINLOCK
  	select DEBUG_MUTEXES
  	select DEBUG_RT_MUTEXES if RT_MUTEXES
  	select DEBUG_LOCK_ALLOC
  	default n
  	help
  	 This feature enables tracking lock contention points
387b14684   Mauro Carvalho Chehab   docs: locking: co...
1053
  	 For more details, see Documentation/locking/lockstat.rst
19193bcad   Waiman Long   locking/Kconfig: ...
1054
1055
1056
1057
1058
1059
1060
1061
  
  	 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.)
e7eebaf6a   Ingo Molnar   [PATCH] pi-futex:...
1062
1063
  config DEBUG_RT_MUTEXES
  	bool "RT Mutex debugging, deadlock detection"
e7eebaf6a   Ingo Molnar   [PATCH] pi-futex:...
1064
1065
1066
1067
  	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.
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1068
  config DEBUG_SPINLOCK
4d9f34ad3   Ingo Molnar   [PATCH] lockdep: ...
1069
  	bool "Spinlock and rw-lock debugging: basic checks"
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1070
  	depends on DEBUG_KERNEL
e335e3eb8   Raghavendra K T   locking/kconfig: ...
1071
  	select UNINLINE_SPIN_UNLOCK
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1072
1073
1074
1075
1076
  	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.
4d9f34ad3   Ingo Molnar   [PATCH] lockdep: ...
1077
1078
1079
1080
1081
1082
  config DEBUG_MUTEXES
  	bool "Mutex debugging: basic checks"
  	depends on DEBUG_KERNEL
  	help
  	 This feature allows mutex semantics violations to be detected and
  	 reported.
230100276   Daniel Vetter   mutex: Add w/w mu...
1083
1084
  config DEBUG_WW_MUTEX_SLOWPATH
  	bool "Wait/wound mutex debugging: Slowpath testing"
f07cbebb6   Waiman Long   locking/Kconfig: ...
1085
  	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
230100276   Daniel Vetter   mutex: Add w/w mu...
1086
1087
1088
1089
1090
1091
1092
1093
1094
  	select DEBUG_LOCK_ALLOC
  	select DEBUG_SPINLOCK
  	select DEBUG_MUTEXES
  	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.
4d6923733   Rob Clark   ww-mutex: clarify...
1095
1096
1097
1098
  	 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.
230100276   Daniel Vetter   mutex: Add w/w mu...
1099

5149cbac4   Waiman Long   locking/rwsem: Ad...
1100
1101
  config DEBUG_RWSEMS
  	bool "RW Semaphore debugging: basic checks"
c71fd893f   Waiman Long   locking/rwsem: Ma...
1102
  	depends on DEBUG_KERNEL
5149cbac4   Waiman Long   locking/rwsem: Ad...
1103
  	help
c71fd893f   Waiman Long   locking/rwsem: Ma...
1104
1105
  	  This debugging feature allows mismatched rw semaphore locks
  	  and unlocks to be detected and reported.
5149cbac4   Waiman Long   locking/rwsem: Ad...
1106

4d9f34ad3   Ingo Molnar   [PATCH] lockdep: ...
1107
1108
  config DEBUG_LOCK_ALLOC
  	bool "Lock debugging: detect incorrect freeing of live locks"
f07cbebb6   Waiman Long   locking/Kconfig: ...
1109
  	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad3   Ingo Molnar   [PATCH] lockdep: ...
1110
1111
  	select DEBUG_SPINLOCK
  	select DEBUG_MUTEXES
f5694788a   Peter Zijlstra   rt_mutex: Add loc...
1112
  	select DEBUG_RT_MUTEXES if RT_MUTEXES
4d9f34ad3   Ingo Molnar   [PATCH] lockdep: ...
1113
1114
1115
1116
1117
1118
1119
1120
  	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.
4d9f34ad3   Ingo Molnar   [PATCH] lockdep: ...
1121
1122
  config LOCKDEP
  	bool
f07cbebb6   Waiman Long   locking/Kconfig: ...
1123
  	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad3   Ingo Molnar   [PATCH] lockdep: ...
1124
  	select STACKTRACE
f9b58e8c7   Stefan Agner   ARM: 8800/1: use ...
1125
  	select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86
4d9f34ad3   Ingo Molnar   [PATCH] lockdep: ...
1126
1127
  	select KALLSYMS
  	select KALLSYMS_ALL
395102db4   Daniel Jordan   sparc64: Use LOCK...
1128
1129
  config LOCKDEP_SMALL
  	bool
4d9f34ad3   Ingo Molnar   [PATCH] lockdep: ...
1130
1131
  config DEBUG_LOCKDEP
  	bool "Lock dependency engine debugging"
517e7aa5b   Adrian Bunk   [PATCH] let the t...
1132
  	depends on DEBUG_KERNEL && LOCKDEP
4d9f34ad3   Ingo Molnar   [PATCH] lockdep: ...
1133
1134
1135
1136
  	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.
d902db1eb   Frederic Weisbecker   sched: Generalize...
1137
1138
  config DEBUG_ATOMIC_SLEEP
  	bool "Sleep inside atomic section checking"
e8f7c70f4   Frederic Weisbecker   sched: Make sleep...
1139
  	select PREEMPT_COUNT
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1140
  	depends on DEBUG_KERNEL
87a4c3759   Christoph Hellwig   kconfig: include ...
1141
  	depends on !ARCH_NO_PREEMPT
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1142
1143
  	help
  	  If you say Y here, various routines which may sleep will become very
d902db1eb   Frederic Weisbecker   sched: Generalize...
1144
1145
1146
  	  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...
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1147

cae2ed9aa   Ingo Molnar   [PATCH] lockdep: ...
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
  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 wont be detected of course.)
  	  The following locking APIs are covered: spinlocks, rwlocks,
  	  mutexes and rwsems.
0af3fe1ef   Paul E. McKenney   locktorture: Add ...
1158
1159
1160
1161
  config LOCK_TORTURE_TEST
  	tristate "torture tests for locking"
  	depends on DEBUG_KERNEL
  	select TORTURE_TEST
0af3fe1ef   Paul E. McKenney   locktorture: Add ...
1162
1163
1164
1165
1166
1167
1168
1169
1170
  	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.
f2a5fec17   Chris Wilson   locking/ww_mutex:...
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
  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.
9eade16b4   Dave Hansen   group locking deb...
1182
  endmenu # lock debugging
8637c0990   Ingo Molnar   [PATCH] lockdep: ...
1183

9eade16b4   Dave Hansen   group locking deb...
1184
1185
  config TRACE_IRQFLAGS
  	bool
5ca43f6c3   Stephen Boyd   lib: consolidate ...
1186
  	help
9eade16b4   Dave Hansen   group locking deb...
1187
1188
  	  Enables hooks to interrupt enabling and disabling for
  	  either tracing or lock debugging.
5ca43f6c3   Stephen Boyd   lib: consolidate ...
1189

8637c0990   Ingo Molnar   [PATCH] lockdep: ...
1190
  config STACKTRACE
0c38e1fe0   Dave Jones   lib: turn CONFIG_...
1191
  	bool "Stack backtrace support"
8637c0990   Ingo Molnar   [PATCH] lockdep: ...
1192
  	depends on STACKTRACE_SUPPORT
0c38e1fe0   Dave Jones   lib: turn CONFIG_...
1193
1194
1195
1196
1197
  	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.
5ca43f6c3   Stephen Boyd   lib: consolidate ...
1198

eecabf567   Theodore Ts'o   random: suppress ...
1199
1200
1201
  config WARN_ALL_UNSEEDED_RANDOM
  	bool "Warn for all uses of unseeded randomness"
  	default n
d06bfd198   Jason A. Donenfeld   random: warn when...
1202
1203
1204
1205
1206
1207
1208
1209
  	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.
eecabf567   Theodore Ts'o   random: suppress ...
1210
1211
1212
1213
1214
1215
  	  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.
4c5d114ea   Thibaut Sautereau   lib/Kconfig.debug...
1216
  	  However, since users cannot do anything actionable to
eecabf567   Theodore Ts'o   random: suppress ...
1217
1218
1219
1220
1221
  	  address this, by default the kernel will issue only a single
  	  warning for the first use of unseeded randomness.
  
  	  Say Y here if you want to receive warnings for all uses of
  	  unseeded randomness.  This will be of use primarily for
4c5d114ea   Thibaut Sautereau   lib/Kconfig.debug...
1222
  	  those developers interested in improving the security of
eecabf567   Theodore Ts'o   random: suppress ...
1223
1224
  	  Linux kernels running on their architecture (or
  	  subarchitecture).
d06bfd198   Jason A. Donenfeld   random: warn when...
1225

1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1226
1227
1228
1229
1230
  config DEBUG_KOBJECT
  	bool "kobject debugging"
  	depends on DEBUG_KERNEL
  	help
  	  If you say Y here, some extra kobject debugging messages will be sent
aca52c398   Mike Rapoport   mm: remove CONFIG...
1231
  	  to the syslog.
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1232

c817a67ec   Russell King   kobject: delayed ...
1233
1234
  config DEBUG_KOBJECT_RELEASE
  	bool "kobject release debugging"
2a999aa0a   Linus Torvalds   Kconfig: make KOB...
1235
  	depends on DEBUG_OBJECTS_TIMERS
c817a67ec   Russell King   kobject: delayed ...
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
  	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 it's
  	  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.
9b2a60c48   Catalin Marinas   Kconfig: clean up...
1251
1252
  config HAVE_DEBUG_BUGVERBOSE
  	bool
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1253
  config DEBUG_BUGVERBOSE
6a108a14f   David Rientjes   kconfig: rename C...
1254
  	bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
9b2a60c48   Catalin Marinas   Kconfig: clean up...
1255
  	depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
8420e7efa   Alexey Dobriyan   Make DEBUG_BUGVER...
1256
  	default y
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2
1257
1258
1259
1260
  	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.
199a9afc3   Dave Jones   [PATCH] Debug var...
1261
1262
  config DEBUG_LIST
  	bool "Debug linked list manipulation"
4520bcb2b   Arnd Bergmann   bug: Avoid Kconfi...
1263
  	depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
199a9afc3   Dave Jones   [PATCH] Debug var...
1264
1265
1266
1267
1268
  	help
  	  Enable this to turn on extended checks in the linked-list
  	  walking routines.
  
  	  If unsure, say N.
8e18faeac   Davidlohr Bueso   lib/plist: rename...
1269
  config DEBUG_PLIST
b8cfff68e   Dan Streetman   lib/plist.c: make...
1270
1271
1272
1273
1274
1275
1276
1277
  	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.
d6ec08420   Jens Axboe   Add CONFIG_DEBUG_...
1278
1279
1280
1281
1282
1283
1284
1285
1286
  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.
1b2439dbb   Arjan van de Ven   debug: add notifi...
1287
1288
1289
1290
1291
1292
1293
1294
1295
  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.
e0e817392   David Howells   CRED: Add some co...
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
  config DEBUG_CREDENTIALS
  	bool "Debug credential management"
  	depends on DEBUG_KERNEL
  	help
  	  Enable this to turn on some debug checking for credential
  	  management.  The additional code keeps track of the number of
  	  pointers from task_structs to any given cred struct, and checks to
  	  see that this number never exceeds the usage count of the cred
  	  struct.
  
  	  Furthermore, if SELinux is enabled, this also checks that the
  	  security pointer in the cred struct is never seen to be invalid.
  
  	  If unsure, say N.
43a0a2a7d   Paul E. McKenney   rcu: Move RCU deb...
1310
  source "kernel/rcu/Kconfig.debug"
2f03e3ca7   Dave Hansen   rcu: Consolidate ...
1311

f303fccb8   Tejun Heo   workqueue: implem...
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
  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.
870d66561   Tejun Heo   block: implement ...
1326
1327
1328
1329
  config DEBUG_BLOCK_EXT_DEVT
          bool "Force extended block device numbers and spread them"
  	depends on DEBUG_KERNEL
  	depends on BLOCK
759f8ca30   Jens Axboe   Change default va...
1330
  	default n
870d66561   Tejun Heo   block: implement ...
1331
  	help
0e11e342b   Tejun Heo   block: add BIG FA...
1332
1333
1334
1335
  	  BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
  	  SOME DISTRIBUTIONS.  DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
  	  YOU ARE DOING.  Distros, please enable this and fix whatever
  	  is broken.
870d66561   Tejun Heo   block: implement ...
1336
1337
1338
1339
1340
1341
1342
  	  Conventionally, block device numbers are allocated from
  	  predetermined contiguous area.  However, extended block area
  	  may introduce non-contiguous block device numbers.  This
  	  option forces most block device numbers to be allocated from
  	  the extended space and spreads them to discover kernel or
  	  userland code paths which assume predetermined contiguous
  	  device number allocation.
55dc7db70   Tejun Heo   init: DEBUG_BLOCK...
1343
1344
1345
1346
1347
  	  Note that turning on this debug option shuffles all the
  	  device numbers for all IDE and SCSI devices including libata
  	  ones, so root partition specified using device number
  	  directly (via rdev or root=MAJ:MIN) won't work anymore.
  	  Textual device names (root=/dev/sdXn) will continue to work.
870d66561   Tejun Heo   block: implement ...
1348
  	  Say N if you are unsure.
757c989b9   Thomas Gleixner   cpu/hotplug: Make...
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
  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.
8d4382881   Akinobu Mita   fault-injection: ...
1361
1362
1363
1364
1365
  config NOTIFIER_ERROR_INJECTION
  	tristate "Notifier error injection"
  	depends on DEBUG_KERNEL
  	select DEBUG_FS
  	help
e41e85cc1   Masanari Iida   treewide: Fix typ...
1366
  	  This option provides the ability to inject artificial errors to
8d4382881   Akinobu Mita   fault-injection: ...
1367
1368
1369
1370
  	  specified notifier chain callbacks. It is useful to test the error
  	  handling of notifier call chain failures.
  
  	  Say N if unsure.
048b9c354   Akinobu Mita   PM: PM notifier e...
1371
1372
1373
1374
1375
  config PM_NOTIFIER_ERROR_INJECT
  	tristate "PM notifier error injection module"
  	depends on PM && NOTIFIER_ERROR_INJECTION
  	default m if PM_DEBUG
  	help
e41e85cc1   Masanari Iida   treewide: Fix typ...
1376
  	  This option provides the ability to inject artificial errors to
048b9c354   Akinobu Mita   PM: PM notifier e...
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
  	  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.
d526e85f6   Benjamin Herrenschmidt   powerpc+of: Renam...
1394
1395
1396
  config OF_RECONFIG_NOTIFIER_ERROR_INJECT
  	tristate "OF reconfig notifier error injection module"
  	depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
08dfb4dde   Akinobu Mita   powerpc: pSeries ...
1397
  	help
e41e85cc1   Masanari Iida   treewide: Fix typ...
1398
  	  This option provides the ability to inject artificial errors to
d526e85f6   Benjamin Herrenschmidt   powerpc+of: Renam...
1399
  	  OF reconfig notifier chain callbacks.  It is controlled
08dfb4dde   Akinobu Mita   powerpc: pSeries ...
1400
  	  through debugfs interface under
d526e85f6   Benjamin Herrenschmidt   powerpc+of: Renam...
1401
  	  /sys/kernel/debug/notifier-error-inject/OF-reconfig/
08dfb4dde   Akinobu Mita   powerpc: pSeries ...
1402
1403
1404
1405
1406
  
  	  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
e12a95f40   Akinobu Mita   notifier-error-in...
1407
  	  be called of-reconfig-notifier-error-inject.
08dfb4dde   Akinobu Mita   powerpc: pSeries ...
1408
1409
  
  	  If unsure, say N.
02fff96a7   Nikolay Aleksandrov   net: add support ...
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
  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.
f1b4bd067   Mikulas Patocka   fault-injection: ...
1432
1433
1434
  config FUNCTION_ERROR_INJECTION
  	def_bool y
  	depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
6ff1cb355   Akinobu Mita   [PATCH] fault-inj...
1435
  config FAULT_INJECTION
1ab8509a3   Andrew Morton   [PATCH] fault-inj...
1436
1437
  	bool "Fault-injection framework"
  	depends on DEBUG_KERNEL
329409aed   Akinobu Mita   [PATCH] fault inj...
1438
1439
1440
  	help
  	  Provide fault-injection framework.
  	  For more details, see Documentation/fault-injection/.
6ff1cb355   Akinobu Mita   [PATCH] fault-inj...
1441

8a8b6502f   Akinobu Mita   [PATCH] fault-inj...
1442
  config FAILSLAB
1ab8509a3   Andrew Morton   [PATCH] fault-inj...
1443
1444
  	bool "Fault-injection capability for kmalloc"
  	depends on FAULT_INJECTION
773ff60e8   Akinobu Mita   SLUB: failslab su...
1445
  	depends on SLAB || SLUB
8a8b6502f   Akinobu Mita   [PATCH] fault-inj...
1446
  	help
1ab8509a3   Andrew Morton   [PATCH] fault-inj...
1447
  	  Provide fault-injection capability for kmalloc.
8a8b6502f   Akinobu Mita   [PATCH] fault-inj...
1448

933e312e7   Akinobu Mita   [PATCH] fault-inj...
1449
1450
  config FAIL_PAGE_ALLOC
  	bool "Fault-injection capabilitiy for alloc_pages()"
1ab8509a3   Andrew Morton   [PATCH] fault-inj...
1451
  	depends on FAULT_INJECTION
933e312e7   Akinobu Mita   [PATCH] fault-inj...
1452
  	help
1ab8509a3   Andrew Morton   [PATCH] fault-inj...
1453
  	  Provide fault-injection capability for alloc_pages().
933e312e7   Akinobu Mita   [PATCH] fault-inj...
1454

c17bb4951   Akinobu Mita   [PATCH] fault-inj...
1455
  config FAIL_MAKE_REQUEST
86327d19f   Dave Jones   Fix typo in new d...
1456
  	bool "Fault-injection capability for disk IO"
581d4e28d   Jens Axboe   block: add fault ...
1457
  	depends on FAULT_INJECTION && BLOCK
c17bb4951   Akinobu Mita   [PATCH] fault-inj...
1458
  	help
1ab8509a3   Andrew Morton   [PATCH] fault-inj...
1459
  	  Provide fault-injection capability for disk IO.
c17bb4951   Akinobu Mita   [PATCH] fault-inj...
1460

581d4e28d   Jens Axboe   block: add fault ...
1461
  config FAIL_IO_TIMEOUT
f4d014395   Takuya Yoshikawa   Kconfig.debug: FA...
1462
  	bool "Fault-injection capability for faking disk interrupts"
581d4e28d   Jens Axboe   block: add fault ...
1463
1464
1465
1466
1467
1468
1469
1470
  	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 wont do anything.
ab51fbab3   Davidlohr Bueso   futex: Fault/erro...
1471
1472
1473
1474
1475
1476
  config FAIL_FUTEX
  	bool "Fault-injection capability for futexes"
  	select DEBUG_FS
  	depends on FAULT_INJECTION && FUTEX
  	help
  	  Provide fault-injection capability for futexes.
f1b4bd067   Mikulas Patocka   fault-injection: ...
1477
1478
1479
1480
1481
  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.
4b1a29a7f   Masami Hiramatsu   error-injection: ...
1482
1483
1484
1485
1486
1487
1488
1489
1490
  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.
f1b4bd067   Mikulas Patocka   fault-injection: ...
1491
1492
1493
  config FAIL_MMC_REQUEST
  	bool "Fault-injection capability for MMC IO"
  	depends on FAULT_INJECTION_DEBUG_FS && MMC
6ff1cb355   Akinobu Mita   [PATCH] fault-inj...
1494
  	help
f1b4bd067   Mikulas Patocka   fault-injection: ...
1495
1496
1497
1498
1499
  	  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.
1df49008f   Akinobu Mita   [PATCH] fault inj...
1500
1501
1502
1503
  
  config FAULT_INJECTION_STACKTRACE_FILTER
  	bool "stacktrace filter for fault-injection capabilities"
  	depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
6d690dcac   Akinobu Mita   fault injection: ...
1504
  	depends on !X86_64
1df49008f   Akinobu Mita   [PATCH] fault inj...
1505
  	select STACKTRACE
f9b58e8c7   Stefan Agner   ARM: 8800/1: use ...
1506
  	select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
1df49008f   Akinobu Mita   [PATCH] fault inj...
1507
1508
  	help
  	  Provide stacktrace filter for fault-injection capabilities
267c4025f   Mathieu Desnoyers   markers: Add samp...
1509

9745512ce   Arjan van de Ven   sched: latencytop...
1510
1511
  config LATENCYTOP
  	bool "Latency measuring infrastructure"
625fdcaa6   Randy Dunlap   latencytop: Fix k...
1512
1513
1514
  	depends on DEBUG_KERNEL
  	depends on STACKTRACE_SUPPORT
  	depends on PROC_FS
f9b58e8c7   Stefan Agner   ARM: 8800/1: use ...
1515
  	select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
9745512ce   Arjan van de Ven   sched: latencytop...
1516
1517
1518
1519
1520
  	select KALLSYMS
  	select KALLSYMS_ALL
  	select STACKTRACE
  	select SCHEDSTATS
  	select SCHED_DEBUG
9745512ce   Arjan van de Ven   sched: latencytop...
1521
1522
1523
  	help
  	  Enable this option if you want to use the LatencyTOP tool
  	  to find out which userspace is blocking on what kernel operations.
8636a1f96   Masahiro Yamada   treewide: surroun...
1524
  source "kernel/trace/Kconfig"
16444a8a4   Arnaldo Carvalho de Melo   ftrace: add basic...
1525

cc3fa8404   Randy Dunlap   lib/Kconfig.debug...
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
  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/debugging-via-ohci1394.txt for more information.
d3deafaa8   Vincent Legoll   lib/: make RUNTIM...
1554
1555
  menuconfig RUNTIME_TESTING_MENU
  	bool "Runtime Testing"
908009e83   Anders Roxell   lib/Kconfig.debug...
1556
  	def_bool y
d3deafaa8   Vincent Legoll   lib/: make RUNTIM...
1557
1558
  
  if RUNTIME_TESTING_MENU
881c51495   Dave Hansen   consolidate runti...
1559
1560
1561
1562
  
  config LKDTM
  	tristate "Linux Kernel Dump Test Tool Module"
  	depends on DEBUG_FS
881c51495   Dave Hansen   consolidate runti...
1563
1564
1565
1566
1567
1568
1569
1570
  	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
10ffebbed   Mauro Carvalho Chehab   docs: fault-injec...
1571
  	Documentation/fault-injection/provoke-crashes.rst
881c51495   Dave Hansen   consolidate runti...
1572
1573
  
  config TEST_LIST_SORT
e327fd7c8   Geert Uytterhoeven   lib: add module s...
1574
1575
  	tristate "Linked list sorting test"
  	depends on DEBUG_KERNEL || m
881c51495   Dave Hansen   consolidate runti...
1576
1577
  	help
  	  Enable this to turn on 'list_sort()' function test. This test is
e327fd7c8   Geert Uytterhoeven   lib: add module s...
1578
1579
  	  executed only once during system boot (so affects only boot time),
  	  or at module load time.
881c51495   Dave Hansen   consolidate runti...
1580
1581
  
  	  If unsure, say N.
c5adae958   Kostenzer Felix   lib: add CONFIG_T...
1582
  config TEST_SORT
5c4e67989   Geert Uytterhoeven   lib: add module s...
1583
1584
  	tristate "Array-based sort test"
  	depends on DEBUG_KERNEL || m
c5adae958   Kostenzer Felix   lib: add CONFIG_T...
1585
  	help
5c4e67989   Geert Uytterhoeven   lib: add module s...
1586
1587
  	  This option enables the self-test function of 'sort()' at boot,
  	  or at module load time.
c5adae958   Kostenzer Felix   lib: add CONFIG_T...
1588
1589
  
  	  If unsure, say N.
881c51495   Dave Hansen   consolidate runti...
1590
1591
1592
1593
  config KPROBES_SANITY_TEST
  	bool "Kprobes sanity tests"
  	depends on DEBUG_KERNEL
  	depends on KPROBES
881c51495   Dave Hansen   consolidate runti...
1594
1595
  	help
  	  This option provides for testing basic kprobes functionality on
5a6cf77f5   Masami Hiramatsu   kprobes: Remove j...
1596
  	  boot. Samples of kprobe and kretprobe are inserted and
881c51495   Dave Hansen   consolidate runti...
1597
1598
1599
1600
1601
1602
1603
  	  verified for functionality.
  
  	  Say N if you are unsure.
  
  config BACKTRACE_SELF_TEST
  	tristate "Self test for the backtrace code"
  	depends on DEBUG_KERNEL
881c51495   Dave Hansen   consolidate runti...
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
  	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.
910a742d4   Michel Lespinasse   rbtree: performan...
1614
1615
  config RBTREE_TEST
  	tristate "Red-Black tree test"
7c993e11a   Cody P Schafer   rbtree: allow tes...
1616
  	depends on DEBUG_KERNEL
910a742d4   Michel Lespinasse   rbtree: performan...
1617
1618
1619
  	help
  	  A benchmark measuring the performance of the rbtree library.
  	  Also includes rbtree invariant checks.
4b4f3accd   Ferdinand Blomqvist   rslib: Add tests ...
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
  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.
fff3fd8a1   Michel Lespinasse   rbtree: add prio ...
1631
1632
  config INTERVAL_TREE_TEST
  	tristate "Interval tree test"
0f789b676   Davidlohr Bueso   lib/interval_tree...
1633
  	depends on DEBUG_KERNEL
a88cc108f   Chris Wilson   lib: Export inter...
1634
  	select INTERVAL_TREE
fff3fd8a1   Michel Lespinasse   rbtree: add prio ...
1635
1636
  	help
  	  A benchmark measuring the performance of the interval tree library
623fd8072   Greg Thelen   percpu: add test ...
1637
1638
1639
1640
1641
1642
1643
1644
  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.
881c51495   Dave Hansen   consolidate runti...
1645
  config ATOMIC64_SELFTEST
55ded9551   Geert Uytterhoeven   lib: add module s...
1646
  	tristate "Perform an atomic64_t self-test"
881c51495   Dave Hansen   consolidate runti...
1647
  	help
55ded9551   Geert Uytterhoeven   lib: add module s...
1648
1649
  	  Enable this option to test the atomic64_t functions at boot or
  	  at module load time.
881c51495   Dave Hansen   consolidate runti...
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
  
  	  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.
64d1d77a4   Andy Shevchenko   hexdump: introduc...
1665
1666
  config TEST_HEXDUMP
  	tristate "Test functions located in the hexdump module at runtime"
881c51495   Dave Hansen   consolidate runti...
1667
1668
  config TEST_STRING_HELPERS
  	tristate "Test functions located in the string_helpers module at runtime"
0b0600c8c   Tobin C. Harding   lib: Add test mod...
1669
1670
  config TEST_STRSCPY
  	tristate "Test strscpy*() family of functions at runtime"
881c51495   Dave Hansen   consolidate runti...
1671
1672
  config TEST_KSTRTOX
  	tristate "Test kstrto*() family of functions at runtime"
707cc7280   Rasmus Villemoes   test_printf: test...
1673
1674
  config TEST_PRINTF
  	tristate "Test printf() family of functions at runtime"
5fd003f56   David Decotigny   test_bitmap: unit...
1675
1676
  config TEST_BITMAP
  	tristate "Test bitmap_*() family of functions at runtime"
5fd003f56   David Decotigny   test_bitmap: unit...
1677
1678
1679
1680
  	help
  	  Enable this option to test the bitmap functions at boot.
  
  	  If unsure, say N.
0e2dc70e3   Johannes Berg   bitfield: add tests
1681
1682
1683
1684
1685
1686
  config TEST_BITFIELD
  	tristate "Test bitfield functions at runtime"
  	help
  	  Enable this option to test the bitfield functions at boot.
  
  	  If unsure, say N.
cfaff0e51   Andy Shevchenko   lib/uuid: add a t...
1687
1688
  config TEST_UUID
  	tristate "Test functions located in the uuid module at runtime"
ad3d6c726   Matthew Wilcox   xarray: Add XArra...
1689
1690
  config TEST_XARRAY
  	tristate "Test the XArray code at runtime"
455a35a6c   Rasmus Villemoes   lib: add runtime ...
1691
1692
  config TEST_OVERFLOW
  	tristate "Test check_*_overflow() functions at runtime"
7e1e77636   Thomas Graf   lib: Resizable, S...
1693
  config TEST_RHASHTABLE
9d6dbe1bb   Geert Uytterhoeven   rhashtable: Make ...
1694
  	tristate "Perform selftest on resizable hash table"
7e1e77636   Thomas Graf   lib: Resizable, S...
1695
1696
1697
1698
  	help
  	  Enable this option to test the rhashtable functions at boot.
  
  	  If unsure, say N.
468a94285   George Spelvin   <linux/hash.h>: A...
1699
1700
  config TEST_HASH
  	tristate "Perform selftest on hash functions"
468a94285   George Spelvin   <linux/hash.h>: A...
1701
  	help
2c956a607   Jason A. Donenfeld   siphash: add cryp...
1702
1703
1704
  	  Enable this option to test the kernel's integer (<linux/hash.h>),
  	  string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
  	  hash functions on boot (or module load).
468a94285   George Spelvin   <linux/hash.h>: A...
1705
1706
1707
  
  	  This is intended to help people writing architecture-specific
  	  optimized versions.  If unsure, say N.
8ab8ba38d   Matthew Wilcox   ida: Start new te...
1708
1709
  config TEST_IDA
  	tristate "Perform selftest on IDA functions"
44091d29f   Jiri Pirko   lib: Introduce pr...
1710
1711
  config TEST_PARMAN
  	tristate "Perform selftest on priority array manager"
44091d29f   Jiri Pirko   lib: Introduce pr...
1712
1713
1714
1715
1716
1717
  	depends on PARMAN
  	help
  	  Enable this option to test priority array manager on boot
  	  (or module load).
  
  	  If unsure, say N.
6aed82de7   Daniel Lezcano   genirq/timings: A...
1718
1719
1720
1721
1722
1723
1724
  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.
8a6f0b47d   Valentin Rothberg   lib: rename TEST_...
1725
  config TEST_LKM
93e9ef83f   Kees Cook   test: add minimal...
1726
  	tristate "Test module loading with 'hello world' module"
93e9ef83f   Kees Cook   test: add minimal...
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
  	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.
3f21a6b7e   Uladzislau Rezki (Sony)   vmalloc: add test...
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
  config TEST_VMALLOC
  	tristate "Test module for stress/performance analysis of vmalloc allocator"
  	default n
         depends on MMU
  	depends on m
  	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.
3e2a4c183   Kees Cook   test: check copy_...
1749
1750
  config TEST_USER_COPY
  	tristate "Test user/kernel boundary protections"
3e2a4c183   Kees Cook   test: check copy_...
1751
1752
1753
1754
1755
1756
1757
1758
1759
  	depends on m
  	help
  	  This builds the "test_user_copy" module that runs sanity checks
  	  on the copy_to/from_user infrastructure, making sure basic
  	  user/kernel boundary testing is working. If it fails to load,
  	  a regression has been detected in the user/kernel memory boundary
  	  protections.
  
  	  If unsure, say N.
64a8946b4   Alexei Starovoitov   net: filter: BPF ...
1760
1761
  config TEST_BPF
  	tristate "Test BPF filter functionality"
98920ba69   Randy Dunlap   net: fix test_bpf...
1762
  	depends on m && NET
64a8946b4   Alexei Starovoitov   net: filter: BPF ...
1763
1764
1765
1766
1767
  	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
3c731eba4   Alexei Starovoitov   bpf: mini eBPF li...
1768
1769
  	  the interpreter code. It also enables test stubs for eBPF maps and
  	  verifier used by user space verifier testsuite.
64a8946b4   Alexei Starovoitov   net: filter: BPF ...
1770
1771
  
  	  If unsure, say N.
509e56b37   Mahesh Bandewar   blackhole_dev: ad...
1772
1773
1774
1775
1776
1777
1778
1779
  config TEST_BLACKHOLE_DEV
  	tristate "Test blackhole netdev functionality"
  	depends on m && NET
  	help
  	  This builds the "test_blackhole_dev" module that validates the
  	  data path through this blackhole netdev.
  
  	  If unsure, say N.
dceeb3e7f   Yury Norov   lib/test_find_bit...
1780
  config FIND_BIT_BENCHMARK
4441fca0a   Yury Norov   lib: test module ...
1781
  	tristate "Test find_bit functions"
4441fca0a   Yury Norov   lib: test module ...
1782
1783
1784
1785
1786
  	help
  	  This builds the "test_find_bit" module that measure find_*_bit()
  	  functions performance.
  
  	  If unsure, say N.
0a8adf584   Kees Cook   test: add firmwar...
1787
1788
  config TEST_FIRMWARE
  	tristate "Test firmware loading via userspace interface"
0a8adf584   Kees Cook   test: add firmwar...
1789
1790
1791
1792
1793
1794
1795
1796
1797
  	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.
9308f2f9e   Luis R. Rodriguez   test_sysctl: add ...
1798
1799
  config TEST_SYSCTL
  	tristate "sysctl test driver"
9308f2f9e   Luis R. Rodriguez   test_sysctl: add ...
1800
1801
1802
1803
1804
1805
1806
  	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.
03c4d42e3   Iurii Zaikin   kernel/sysctl-tes...
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
  config SYSCTL_KUNIT_TEST
  	bool "KUnit test for sysctl"
  	depends on KUNIT
  	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.
e704f93af   David Riley   kernel: time: Add...
1817
1818
  config TEST_UDELAY
  	tristate "udelay test driver"
e704f93af   David Riley   kernel: time: Add...
1819
1820
1821
1822
1823
  	help
  	  This builds the "udelay_test" module that helps to make sure
  	  that udelay() is working properly.
  
  	  If unsure, say N.
2bf9e0ab0   Ingo Molnar   locking/static_ke...
1824
1825
  config TEST_STATIC_KEYS
  	tristate "Test static keys"
579e1acb1   Jason Baron   jump_label: Provi...
1826
1827
  	depends on m
  	help
2bf9e0ab0   Ingo Molnar   locking/static_ke...
1828
  	  Test the static key interfaces.
579e1acb1   Jason Baron   jump_label: Provi...
1829
1830
  
  	  If unsure, say N.
d9c6a72d6   Luis R. Rodriguez   kmod: add test dr...
1831
1832
  config TEST_KMOD
  	tristate "kmod stress tester"
d9c6a72d6   Luis R. Rodriguez   kmod: add test dr...
1833
  	depends on m
d9c6a72d6   Luis R. Rodriguez   kmod: add test dr...
1834
  	depends on NETDEVICES && NET_CORE && INET # for TUN
ae3d6a323   YueHaibing   lib/Kconfig.debug...
1835
  	depends on BLOCK
d9c6a72d6   Luis R. Rodriguez   kmod: add test dr...
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
  	select TEST_LKM
  	select XFS_FS
  	select TUN
  	select BTRFS_FS
  	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.
e4dace361   Florian Fainelli   lib: add test mod...
1856
1857
1858
1859
1860
1861
1862
1863
1864
  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.
ce76d938d   Alexander Shishkin   lib: Add memcat_p...
1865
1866
1867
1868
1869
1870
1871
  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.
a2818ee4d   Joe Lawrence   selftests/livepat...
1872
1873
1874
  config TEST_LIVEPATCH
  	tristate "Test livepatching"
  	default n
bae054372   Joe Lawrence   selftests/livepat...
1875
  	depends on DYNAMIC_DEBUG
a2818ee4d   Joe Lawrence   selftests/livepat...
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
  	depends on LIVEPATCH
  	depends on m
  	help
  	  Test kernel livepatching features for correctness.  The tests will
  	  load test modules that will be livepatched in various scenarios.
  
  	  To run all the livepatching tests:
  
  	  make -C tools/testing/selftests TARGETS=livepatch run_tests
  
  	  Alternatively, individual tests may be invoked:
  
  	  tools/testing/selftests/livepatch/test-callbacks.sh
  	  tools/testing/selftests/livepatch/test-livepatch.sh
  	  tools/testing/selftests/livepatch/test-shadow-vars.sh
  
  	  If unsure, say N.
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  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).
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  config TEST_STACKINIT
  	tristate "Test level of stack variable initialization"
  	help
  	  Test if the kernel is zero-initializing stack variables and
  	  padding. Coverage is controlled by compiler flags,
  	  CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
  	  or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
  
  	  If unsure, say N.
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  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.
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  endif # RUNTIME_TESTING_MENU
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  config MEMTEST
  	bool "Memtest"
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  	---help---
  	  This option adds a kernel parameter 'memtest', which allows memtest
  	  to be set.
  	        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 BUG_ON_DATA_CORRUPTION
  	bool "Trigger a BUG when data corruption is detected"
  	select DEBUG_LIST
  	help
  	  Select this option if the kernel should BUG when it encounters
  	  data corruption in kernel memory structures when they get checked
  	  for validity.
  
  	  If unsure, say N.
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  source "samples/Kconfig"
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  source "lib/Kconfig.kgdb"
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c6d308534   Andrey Ryabinin   UBSAN: run-time u...
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  source "lib/Kconfig.ubsan"
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  config ARCH_HAS_DEVMEM_IS_ALLOWED
  	bool
  
  config STRICT_DEVMEM
  	bool "Filter access to /dev/mem"
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  	depends on MMU && DEVMEM
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  	depends on ARCH_HAS_DEVMEM_IS_ALLOWED
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  	default y if PPC || X86 || ARM64
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  	---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.
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  	  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
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  	---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.
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  	  If this option is switched on, the /dev/mem file only allows
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  	  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.
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  	  If in doubt, say Y.
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  source "arch/$(SRCARCH)/Kconfig.debug"
  
  endmenu # Kernel hacking