# 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
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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()
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messages to be added to the output of the syslog() system
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call and at the console.
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The timestamp is always recorded internally, and exported
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to /dev/kmsg. This flag just specifies if the timestamp should
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be included, not that the timestamp is recorded.
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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_TIME_FROM_ARM_ARCH_TIMER
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bool "Timing from ARM architected timer"
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depends on PRINTK_TIME && ARM_ARCH_TIMER && NO_GKI
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config PRINTK_CALLER
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bool "Show caller information on printks"
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depends on PRINTK
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help
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Selecting this option causes printk() to add a caller "thread id" (if
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in task context) or a caller "processor id" (if not in task context)
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to every message.
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This option is intended for environments where multiple threads
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concurrently call printk() for many times, for it is difficult to
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interpret without knowing where these lines (or sometimes individual
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line which was divided into multiple lines due to race) came from.
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Since toggling after boot makes the code racy, currently there is
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no option to enable/disable at the kernel command line parameter or
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sysfs interface.
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config CONSOLE_LOGLEVEL_DEFAULT
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int "Default console loglevel (1-15)"
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range 1 15
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default "7"
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help
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Default loglevel to determine what will be printed on the console.
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Setting a default here is equivalent to passing in loglevel=<x> in
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the kernel bootargs. loglevel=<x> continues to override whatever
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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
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option.
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config CONSOLE_LOGLEVEL_QUIET
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int "quiet console loglevel (1-15)"
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range 1 15
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default "4"
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help
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loglevel to use when "quiet" is passed on the kernel commandline.
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When "quiet" is passed on the kernel commandline this loglevel
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will be used as the loglevel. IOW passing "quiet" will be the
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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)"
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range 1 7
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default "4"
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help
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Default log level for printk statements with no specified priority.
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This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
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that are auditing their logs closely may want to set it to a lower
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priority.
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Note: This does not affect what message level gets printed on the console
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by default. To change that, use loglevel=<x> in the kernel bootargs,
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or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
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config BOOT_PRINTK_DELAY
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bool "Delay each boot printk message by N milliseconds"
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depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
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help
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This build option allows you to read kernel boot messages
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by inserting a short delay after each one. The delay is
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specified in milliseconds on the kernel command line,
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using "boot_delay=N".
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It is likely that you would also need to use "lpj=M" to preset
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the "loops per jiffie" value.
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See a previous boot log for the "lpj" value to use for your
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system, and then set "lpj=M" before setting "boot_delay=N".
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NOTE: Using this option may adversely affect SMP systems.
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I.e., processors other than the first one may not boot up.
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BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
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what it believes to be lockup conditions.
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config DYNAMIC_DEBUG
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bool "Enable dynamic printk() support"
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default n
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depends on PRINTK
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depends on (DEBUG_FS || PROC_FS)
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select DYNAMIC_DEBUG_CORE
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help
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Compiles debug level messages into the kernel, which would not
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otherwise be available at runtime. These messages can then be
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enabled/disabled based on various levels of scope - per source file,
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function, module, format string, and line number. This mechanism
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implicitly compiles in all pr_debug() and dev_dbg() calls, which
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enlarges the kernel text size by about 2%.
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If a source file is compiled with DEBUG flag set, any
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pr_debug() calls in it are enabled by default, but can be
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disabled at runtime as below. Note that DEBUG flag is
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turned on by many CONFIG_*DEBUG* options.
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Usage:
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Dynamic debugging is controlled via the 'dynamic_debug/control' file,
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which is contained in the 'debugfs' filesystem or procfs.
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Thus, the debugfs or procfs filesystem must first be mounted before
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making use of this feature.
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We refer the control file as: <debugfs>/dynamic_debug/control. This
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file contains a list of the debug statements that can be enabled. The
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format for each line of the file is:
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filename:lineno [module]function flags format
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filename : source file of the debug statement
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lineno : line number of the debug statement
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module : module that contains the debug statement
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function : function that contains the debug statement
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flags : '=p' means the line is turned 'on' for printing
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format : the format used for the debug statement
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From a live system:
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nullarbor:~ # cat <debugfs>/dynamic_debug/control
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# filename:lineno [module]function flags format
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fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
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fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
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fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
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Example usage:
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// enable the message at line 1603 of file svcsock.c
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nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
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<debugfs>/dynamic_debug/control
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// enable all the messages in file svcsock.c
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nullarbor:~ # echo -n 'file svcsock.c +p' >
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<debugfs>/dynamic_debug/control
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// enable all the messages in the NFS server module
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nullarbor:~ # echo -n 'module nfsd +p' >
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<debugfs>/dynamic_debug/control
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// enable all 12 messages in the function svc_process()
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nullarbor:~ # echo -n 'func svc_process +p' >
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<debugfs>/dynamic_debug/control
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// disable all 12 messages in the function svc_process()
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nullarbor:~ # echo -n 'func svc_process -p' >
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<debugfs>/dynamic_debug/control
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See Documentation/admin-guide/dynamic-debug-howto.rst for additional
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information.
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config DYNAMIC_DEBUG_CORE
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bool "Enable core function of dynamic debug support"
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depends on PRINTK
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depends on (DEBUG_FS || PROC_FS)
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help
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Enable core functional support of dynamic debug. It is useful
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when you want to tie dynamic debug to your kernel modules with
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DYNAMIC_DEBUG_MODULE defined for each of them, especially for
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the case of embedded system where the kernel image size is
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sensitive for people.
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config SYMBOLIC_ERRNAME
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bool "Support symbolic error names in printf"
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default y if PRINTK
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help
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If you say Y here, the kernel's printf implementation will
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be able to print symbolic error names such as ENOSPC instead
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of the number 28. It makes the kernel image slightly larger
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(about 3KB), but can make the kernel logs easier to read.
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config DEBUG_BUGVERBOSE
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bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
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depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
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default y
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help
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Say Y here to make BUG() panics output the file name and line number
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of the BUG call as well as the EIP and oops trace. This aids
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debugging but costs about 70-100K of memory.
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endmenu # "printk and dmesg options"
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menu "Compile-time checks and compiler options"
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config DEBUG_INFO
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bool "Compile the kernel with debug info"
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depends on DEBUG_KERNEL && !COMPILE_TEST
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help
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If you say Y here the resulting kernel image will include
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debugging info resulting in a larger kernel image.
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This adds debug symbols to the kernel and modules (gcc -g), and
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is needed if you intend to use kernel crashdump or binary object
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tools like crash, kgdb, LKCD, gdb, etc on the kernel.
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Say Y here only if you plan to debug the kernel.
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If unsure, say N.
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if DEBUG_INFO
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config DEBUG_INFO_REDUCED
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bool "Reduce debugging information"
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help
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If you say Y here gcc is instructed to generate less debugging
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information for structure types. This means that tools that
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need full debugging information (like kgdb or systemtap) won't
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be happy. But if you merely need debugging information to
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resolve line numbers there is no loss. Advantage is that
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build directory object sizes shrink dramatically over a full
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DEBUG_INFO build and compile times are reduced too.
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Only works with newer gcc versions.
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config DEBUG_INFO_COMPRESSED
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bool "Compressed debugging information"
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depends on $(cc-option,-gz=zlib)
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depends on $(ld-option,--compress-debug-sections=zlib)
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help
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Compress the debug information using zlib. Requires GCC 5.0+ or Clang
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5.0+, binutils 2.26+, and zlib.
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Users of dpkg-deb via scripts/package/builddeb may find an increase in
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size of their debug .deb packages with this config set, due to the
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debug info being compressed with zlib, then the object files being
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recompressed with a different compression scheme. But this is still
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preferable to setting $KDEB_COMPRESS to "none" which would be even
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larger.
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config DEBUG_INFO_SPLIT
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bool "Produce split debuginfo in .dwo files"
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depends on $(cc-option,-gsplit-dwarf)
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help
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Generate debug info into separate .dwo files. This significantly
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reduces the build directory size for builds with DEBUG_INFO,
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because it stores the information only once on disk in .dwo
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files instead of multiple times in object files and executables.
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In addition the debug information is also compressed.
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Requires recent gcc (4.7+) and recent gdb/binutils.
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Any tool that packages or reads debug information would need
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to know about the .dwo files and include them.
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Incompatible with older versions of ccache.
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config DEBUG_INFO_DWARF4
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bool "Generate dwarf4 debuginfo"
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depends on $(cc-option,-gdwarf-4)
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help
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Generate dwarf4 debug info. This requires recent versions
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of gcc and gdb. It makes the debug information larger.
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But it significantly improves the success of resolving
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variables in gdb on optimized code.
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config DEBUG_INFO_BTF
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bool "Generate BTF typeinfo"
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depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
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depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
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help
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Generate deduplicated BTF type information from DWARF debug info.
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Turning this on expects presence of pahole tool, which will convert
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DWARF type info into equivalent deduplicated BTF type info.
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config GDB_SCRIPTS
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bool "Provide GDB scripts for kernel debugging"
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help
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This creates the required links to GDB helper scripts in the
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build directory. If you load vmlinux into gdb, the helper
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scripts will be automatically imported by gdb as well, and
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additional functions are available to analyze a Linux kernel
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instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
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for further details.
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endif # DEBUG_INFO
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config ENABLE_MUST_CHECK
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bool "Enable __must_check logic"
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default y
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help
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Enable the __must_check logic in the kernel build. Disable this to
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suppress the "warning: ignoring return value of 'foo', declared with
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attribute warn_unused_result" messages.
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config FRAME_WARN
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int "Warn for stack frames larger than"
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range 0 8192
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default 2048 if GCC_PLUGIN_LATENT_ENTROPY
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default 2048 if PARISC
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default 1536 if (!64BIT && XTENSA)
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default 1280 if KASAN && !64BIT
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default 1024 if !64BIT
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default 2048 if 64BIT
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help
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Tell gcc to warn at build time for stack frames larger than this.
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Setting this too low will cause a lot of warnings.
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Setting it to 0 disables the warning.
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config STRIP_ASM_SYMS
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bool "Strip assembler-generated symbols during link"
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default n
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help
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Strip internal assembler-generated symbols during a link (symbols
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that look like '.Lxxx') so they don't pollute the output of
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get_wchan() and suchlike.
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config READABLE_ASM
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bool "Generate readable assembler code"
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depends on DEBUG_KERNEL
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help
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Disable some compiler optimizations that tend to generate human unreadable
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assembler output. This may make the kernel slightly slower, but it helps
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to keep kernel developers who have to stare a lot at assembler listings
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sane.
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config HEADERS_INSTALL
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bool "Install uapi headers to usr/include"
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depends on !UML
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help
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This option will install uapi headers (headers exported to user-space)
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into the usr/include directory for use during the kernel build.
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This is unneeded for building the kernel itself, but needed for some
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user-space program samples. It is also needed by some features such
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as uapi header sanity checks.
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config DEBUG_SECTION_MISMATCH
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bool "Enable full Section mismatch analysis"
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help
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The section mismatch analysis checks if there are illegal
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references from one section to another section.
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During linktime or runtime, some sections are dropped;
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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
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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.
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When inlining a function annotated with __init in a non-init
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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
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a larger kernel).
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config SECTION_MISMATCH_WARN_ONLY
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bool "Make section mismatch errors non-fatal"
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default y
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help
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If you say N here, the build process will fail if there are any
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section mismatch, instead of just throwing warnings.
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If unsure, say Y.
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config DEBUG_FORCE_FUNCTION_ALIGN_32B
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bool "Force all function address 32B aligned" if EXPERT
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help
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There are cases that a commit from one domain changes the function
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address alignment of other domains, and cause magic performance
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bump (regression or improvement). Enable this option will help to
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verify if the bump is caused by function alignment changes, while
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it will slightly increase the kernel size and affect icache usage.
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It is mainly for debug and performance tuning use.
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#
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# Select this config option from the architecture Kconfig, if it
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# is preferred to always offer frame pointers as a config
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# option on the architecture (regardless of KERNEL_DEBUG):
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#
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config ARCH_WANT_FRAME_POINTERS
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bool
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config FRAME_POINTER
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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
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larger and slower, but it gives very useful debugging information
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in case of kernel bugs. (precise oopses/stacktraces/warnings)
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config STACK_VALIDATION
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bool "Compile-time stack metadata validation"
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depends on HAVE_STACK_VALIDATION
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default n
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help
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Add compile-time checks to validate stack metadata, including frame
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pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
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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
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tools/objtool/Documentation/stack-validation.txt.
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config VMLINUX_VALIDATION
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bool
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depends on STACK_VALIDATION && DEBUG_ENTRY && !PARAVIRT
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default y
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config DEBUG_FORCE_WEAK_PER_CPU
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bool "Force weak per-cpu definitions"
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depends on DEBUG_KERNEL
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help
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s390 and alpha require percpu variables in modules to be
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defined weak to work around addressing range issue which
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puts the following two restrictions on percpu variable
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definitions.
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1. percpu symbols must be unique whether static or not
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2. percpu variables can't be defined inside a function
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To ensure that generic code follows the above rules, this
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option forces all percpu variables to be defined as weak.
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endmenu # "Compiler options"
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menu "Generic Kernel Debugging Instruments"
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config MAGIC_SYSRQ
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bool "Magic SysRq key"
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depends on !UML
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help
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If you say Y here, you will have some control over the system even
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if the system crashes for example during kernel debugging (e.g., you
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will be able to flush the buffer cache to disk, reboot the system
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immediately or dump some status information). This is accomplished
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by pressing various keys while holding SysRq (Alt+PrintScreen). It
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also works on a serial console (on PC hardware at least), if you
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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>.
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Don't say Y unless you really know what this hack does.
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config MAGIC_SYSRQ_DEFAULT_ENABLE
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hex "Enable magic SysRq key functions by default"
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depends on MAGIC_SYSRQ
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default 0x1
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help
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Specifies which SysRq key functions are enabled by default.
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This may be set to 1 or 0 to enable or disable them all, or
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to a bitmask as described in Documentation/admin-guide/sysrq.rst.
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config MAGIC_SYSRQ_SERIAL
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bool "Enable magic SysRq key over serial"
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depends on MAGIC_SYSRQ
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default y
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help
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Many embedded boards have a disconnected TTL level serial which can
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generate some garbage that can lead to spurious false sysrq detects.
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This option allows you to decide whether you want to enable the
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magic SysRq key.
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config MAGIC_SYSRQ_SERIAL_SEQUENCE
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string "Char sequence that enables magic SysRq over serial"
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depends on MAGIC_SYSRQ_SERIAL
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default ""
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help
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Specifies a sequence of characters that can follow BREAK to enable
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SysRq on a serial console.
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If unsure, leave an empty string and the option will not be enabled.
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config DEBUG_FS
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bool "Debug Filesystem"
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help
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debugfs is a virtual file system that kernel developers use to put
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debugging files into. Enable this option to be able to read and
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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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choice
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prompt "Debugfs default access"
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depends on DEBUG_FS
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default DEBUG_FS_ALLOW_ALL
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help
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This selects the default access restrictions for debugfs.
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It can be overridden with kernel command line option
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debugfs=[on,no-mount,off]. The restrictions apply for API access
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and filesystem registration.
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config DEBUG_FS_ALLOW_ALL
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bool "Access normal"
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help
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No restrictions apply. Both API and filesystem registration
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is on. This is the normal default operation.
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config DEBUG_FS_DISALLOW_MOUNT
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bool "Do not register debugfs as filesystem"
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help
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The API is open but filesystem is not loaded. Clients can still do
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their work and read with debug tools that do not need
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debugfs filesystem.
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config DEBUG_FS_ALLOW_NONE
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bool "No access"
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help
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Access is off. Clients get -PERM when trying to create nodes in
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debugfs tree and debugfs is not registered as a filesystem.
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Client can then back-off or continue without debugfs access.
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endchoice
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source "lib/Kconfig.kgdb"
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source "lib/Kconfig.ubsan"
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source "lib/Kconfig.kcsan"
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endmenu
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config DEBUG_KERNEL
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bool "Kernel debugging"
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help
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Say Y here if you are developing drivers or trying to debug and
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identify kernel problems.
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config DEBUG_MISC
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bool "Miscellaneous debug code"
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default DEBUG_KERNEL
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depends on DEBUG_KERNEL
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help
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Say Y here if you need to enable miscellaneous debug code that should
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be under a more specific debug option but isn't.
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menu "Memory Debugging"
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source "mm/Kconfig.debug"
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config DEBUG_OBJECTS
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bool "Debug object operations"
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depends on DEBUG_KERNEL
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help
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If you say Y here, additional code will be inserted into the
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kernel to track the life time of various objects and validate
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the operations on those objects.
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config DEBUG_OBJECTS_SELFTEST
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bool "Debug objects selftest"
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depends on DEBUG_OBJECTS
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help
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This enables the selftest of the object debug code.
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config DEBUG_OBJECTS_FREE
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bool "Debug objects in freed memory"
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depends on DEBUG_OBJECTS
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help
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This enables checks whether a k/v free operation frees an area
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which contains an object which has not been deactivated
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properly. This can make kmalloc/kfree-intensive workloads
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much slower.
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config DEBUG_OBJECTS_TIMERS
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bool "Debug timer objects"
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depends on DEBUG_OBJECTS
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help
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If you say Y here, additional code will be inserted into the
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timer routines to track the life time of timer objects and
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validate the timer operations.
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config DEBUG_OBJECTS_WORK
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bool "Debug work objects"
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depends on DEBUG_OBJECTS
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help
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If you say Y here, additional code will be inserted into the
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work queue routines to track the life time of work objects and
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validate the work operations.
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config DEBUG_OBJECTS_RCU_HEAD
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bool "Debug RCU callbacks objects"
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depends on DEBUG_OBJECTS
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help
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Enable this to turn on debugging of RCU list heads (call_rcu() usage).
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config DEBUG_OBJECTS_PERCPU_COUNTER
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bool "Debug percpu counter objects"
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depends on DEBUG_OBJECTS
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help
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If you say Y here, additional code will be inserted into the
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percpu counter routines to track the life time of percpu counter
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objects and validate the percpu counter operations.
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config DEBUG_OBJECTS_ENABLE_DEFAULT
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int "debug_objects bootup default value (0-1)"
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range 0 1
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default "1"
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depends on DEBUG_OBJECTS
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help
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Debug objects boot parameter default value
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config DEBUG_SLAB
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bool "Debug slab memory allocations"
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depends on DEBUG_KERNEL && SLAB
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help
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Say Y here to have the kernel do limited verification on memory
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allocation as well as poisoning memory on free to catch use of freed
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memory. This can make kmalloc/kfree-intensive workloads much slower.
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config SLUB_DEBUG_ON
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bool "SLUB debugging on by default"
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depends on SLUB && SLUB_DEBUG
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default n
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help
|
Boot with debugging on by default. SLUB boots by default with
|
the runtime debug capabilities switched off. Enabling this is
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equivalent to specifying the "slub_debug" parameter on boot.
|
There is no support for more fine grained debug control like
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possible with slub_debug=xxx. SLUB debugging may be switched
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off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
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"slub_debug=-".
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config SLUB_STATS
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default n
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bool "Enable SLUB performance statistics"
|
depends on SLUB && SYSFS
|
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
|
|
config HAVE_DEBUG_KMEMLEAK
|
bool
|
|
config DEBUG_KMEMLEAK
|
bool "Kernel memory leak detector"
|
depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
|
select DEBUG_FS
|
select STACKTRACE if STACKTRACE_SUPPORT
|
select KALLSYMS
|
select CRC32
|
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
|
allocations. See Documentation/dev-tools/kmemleak.rst for more
|
details.
|
|
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).
|
|
config DEBUG_KMEMLEAK_MEM_POOL_SIZE
|
int "Kmemleak memory pool size"
|
depends on DEBUG_KMEMLEAK
|
range 200 1000000
|
default 16000
|
help
|
Kmemleak must track all the memory allocations to avoid
|
reporting false positives. Since memory may be allocated or
|
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.
|
|
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.
|
|
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.
|
|
config DEBUG_STACK_USAGE
|
bool "Stack utilization instrumentation"
|
depends on DEBUG_KERNEL && !IA64
|
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 SCHED_STACK_END_CHECK
|
bool "Detect stack corruption on calls to schedule()"
|
depends on DEBUG_KERNEL
|
default n
|
help
|
This option checks for a stack overrun on calls to schedule().
|
If the stack end location is found to be over written always panic as
|
the content of the corrupted region can no longer be trusted.
|
This is to ensure no erroneous behaviour occurs which could result in
|
data corruption or a sporadic crash at a later stage once the region
|
is examined. The runtime overhead introduced is minimal.
|
|
config ARCH_HAS_DEBUG_VM_PGTABLE
|
bool
|
help
|
An architecture should select this when it can successfully
|
build and run DEBUG_VM_PGTABLE.
|
|
config DEBUG_VM
|
bool "Debug VM"
|
depends on DEBUG_KERNEL
|
help
|
Enable this to turn on extended checks in the virtual-memory system
|
that may impact performance.
|
|
If unsure, say N.
|
|
config DEBUG_VM_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.
|
|
config DEBUG_VM_RB
|
bool "Debug VM red-black trees"
|
depends on DEBUG_VM
|
help
|
Enable VM red-black tree debugging information and extra validations.
|
|
If unsure, say N.
|
|
config DEBUG_VM_PGFLAGS
|
bool "Debug page-flags operations"
|
depends on DEBUG_VM
|
help
|
Enables extra validation on page flags operations.
|
|
If unsure, say N.
|
|
config DEBUG_VM_PGTABLE
|
bool "Debug arch page table for semantics compliance"
|
depends on MMU
|
depends on ARCH_HAS_DEBUG_VM_PGTABLE
|
default y if DEBUG_VM
|
help
|
This option provides a debug method which can be used to test
|
architecture page table helper functions on various platforms in
|
verifying if they comply with expected generic MM semantics. This
|
will help architecture code in making sure that any changes or
|
new additions of these helpers still conform to expected
|
semantics of the generic MM. Platforms will have to opt in for
|
this through ARCH_HAS_DEBUG_VM_PGTABLE.
|
|
If unsure, say N.
|
|
config ARCH_HAS_DEBUG_VIRTUAL
|
bool
|
|
config DEBUG_VIRTUAL
|
bool "Debug VM translations"
|
depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
|
help
|
Enable some costly sanity checks in virtual to page code. This can
|
catch mistakes with virt_to_page() and friends.
|
|
If unsure, say N.
|
|
config DEBUG_NOMMU_REGIONS
|
bool "Debug the global anon/private NOMMU mapping region tree"
|
depends on DEBUG_KERNEL && !MMU
|
help
|
This option causes the global tree of anonymous and private mapping
|
regions to be regularly checked for invalid topology.
|
|
config DEBUG_MEMORY_INIT
|
bool "Debug memory initialisation" if EXPERT
|
default !EXPERT
|
help
|
Enable this for additional checks during memory initialisation.
|
The sanity checks verify aspects of the VM such as the memory model
|
and other information provided by the architecture. Verbose
|
information will be printed at KERN_DEBUG loglevel depending
|
on the mminit_loglevel= command-line option.
|
|
If unsure, say Y
|
|
config MEMORY_NOTIFIER_ERROR_INJECT
|
tristate "Memory hotplug notifier error injection module"
|
depends on MEMORY_HOTPLUG_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
|
This option enables additional error checking for high memory
|
systems. Disable for production systems.
|
|
config HAVE_DEBUG_STACKOVERFLOW
|
bool
|
|
config DEBUG_STACKOVERFLOW
|
bool "Check for stack overflows"
|
depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
|
help
|
Say Y here if you want to check for overflows of kernel, IRQ
|
and exception stacks (if your architecture uses them). This
|
option will show detailed messages if free stack space drops
|
below a certain limit.
|
|
These kinds of bugs usually occur when call-chains in the
|
kernel get too deep, especially when interrupts are
|
involved.
|
|
Use this in cases where you see apparently random memory
|
corruption, especially if it appears in 'struct thread_info'
|
|
If in doubt, say "N".
|
|
source "lib/Kconfig.kasan"
|
source "lib/Kconfig.kfence"
|
|
endmenu # "Memory Debugging"
|
|
config DEBUG_SHIRQ
|
bool "Debug shared IRQ handlers"
|
depends on DEBUG_KERNEL
|
help
|
Enable this to generate a spurious interrupt just before a shared
|
interrupt handler is deregistered (generating one when registering
|
is currently disabled). Drivers need to handle this correctly. Some
|
don't and need to be caught.
|
|
menu "Debug Oops, Lockups and Hangs"
|
|
config PANIC_ON_OOPS
|
bool "Panic on Oops"
|
help
|
Say Y here to enable the kernel to panic when it oopses. This
|
has the same effect as setting oops=panic on the kernel command
|
line.
|
|
This feature is useful to ensure that the kernel does not do
|
anything erroneous after an oops which could result in data
|
corruption or other issues.
|
|
Say N if unsure.
|
|
config PANIC_ON_OOPS_VALUE
|
int
|
range 0 1
|
default 0 if !PANIC_ON_OOPS
|
default 1 if PANIC_ON_OOPS
|
|
config PANIC_TIMEOUT
|
int "panic timeout"
|
default 0
|
help
|
Set the timeout value (in seconds) until a reboot occurs when
|
the kernel panics. If n = 0, then we wait forever. A timeout
|
value n > 0 will wait n seconds before rebooting, while a timeout
|
value n < 0 will reboot immediately.
|
|
config LOCKUP_DETECTOR
|
bool
|
|
config SOFTLOCKUP_DETECTOR
|
bool "Detect Soft Lockups"
|
depends on DEBUG_KERNEL && !S390
|
select LOCKUP_DETECTOR
|
help
|
Say Y here to enable the kernel to act as a watchdog to detect
|
soft lockups.
|
|
Softlockups are bugs that cause the kernel to loop in kernel
|
mode for more than 20 seconds, without giving other tasks a
|
chance to run. The current stack trace is displayed upon
|
detection and the system will stay locked up.
|
|
config 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
|
|
config HARDLOCKUP_DETECTOR_PERF
|
bool
|
select SOFTLOCKUP_DETECTOR
|
|
#
|
# Enables a timestamp based low pass filter to compensate for perf based
|
# hard lockup detection which runs too fast due to turbo modes.
|
#
|
config HARDLOCKUP_CHECK_TIMESTAMP
|
bool
|
|
#
|
# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
|
# lockup detector rather than the perf based detector.
|
#
|
config HAVE_HARDLOCKUP_DETECTOR_OTHER_CPU
|
def_bool y
|
depends on NO_GKI
|
depends on SMP
|
depends on !HAVE_HARDLOCKUP_DETECTOR_PERF && !HAVE_HARDLOCKUP_DETECTOR_ARCH
|
|
config HARDLOCKUP_DETECTOR_OTHER_CPU
|
bool
|
select SOFTLOCKUP_DETECTOR
|
|
config HARDLOCKUP_DETECTOR
|
bool "Detect Hard Lockups"
|
depends on DEBUG_KERNEL && !S390
|
depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH || HAVE_HARDLOCKUP_DETECTOR_OTHER_CPU
|
select LOCKUP_DETECTOR
|
select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
|
select HARDLOCKUP_DETECTOR_OTHER_CPU if HAVE_HARDLOCKUP_DETECTOR_OTHER_CPU
|
help
|
Say Y here to enable the kernel to act as a watchdog to detect
|
hard lockups.
|
|
Hardlockups are bugs that cause the CPU to loop in kernel mode
|
for more than 10 seconds, without letting other interrupts have a
|
chance to run. The current stack trace is displayed upon detection
|
and the system will stay locked up.
|
|
config BOOTPARAM_HARDLOCKUP_PANIC
|
bool "Panic (Reboot) On Hard Lockups"
|
depends on HARDLOCKUP_DETECTOR
|
help
|
Say Y here to enable the kernel to panic on "hard lockups",
|
which are bugs that cause the kernel to loop in kernel
|
mode with interrupts disabled for more than 10 seconds (configurable
|
using the watchdog_thresh sysctl).
|
|
Say N if unsure.
|
|
config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
|
int
|
depends on HARDLOCKUP_DETECTOR
|
range 0 1
|
default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
|
default 1 if BOOTPARAM_HARDLOCKUP_PANIC
|
|
config DETECT_HUNG_TASK
|
bool "Detect Hung Tasks"
|
depends on DEBUG_KERNEL
|
default SOFTLOCKUP_DETECTOR
|
help
|
Say Y here to enable the kernel to detect "hung tasks",
|
which are bugs that cause the task to be stuck in
|
uninterruptible "D" state indefinitely.
|
|
When a hung task is detected, the kernel will print the
|
current stack trace (which you should report), but the
|
task will stay in uninterruptible state. If lockdep is
|
enabled then all held locks will also be reported. This
|
feature has negligible overhead.
|
|
config DEFAULT_HUNG_TASK_TIMEOUT
|
int "Default timeout for hung task detection (in seconds)"
|
depends on DETECT_HUNG_TASK
|
default 120
|
help
|
This option controls the default timeout (in seconds) used
|
to determine when a task has become non-responsive and should
|
be considered hung.
|
|
It can be adjusted at runtime via the kernel.hung_task_timeout_secs
|
sysctl or by writing a value to
|
/proc/sys/kernel/hung_task_timeout_secs.
|
|
A timeout of 0 disables the check. The default is two minutes.
|
Keeping the default should be fine in most cases.
|
|
config BOOTPARAM_HUNG_TASK_PANIC
|
bool "Panic (Reboot) On Hung Tasks"
|
depends on DETECT_HUNG_TASK
|
help
|
Say Y here to enable the kernel to panic on "hung tasks",
|
which are bugs that cause the kernel to leave a task stuck
|
in uninterruptible "D" state.
|
|
The panic can be used in combination with panic_timeout,
|
to cause the system to reboot automatically after a
|
hung task has been detected. This feature is useful for
|
high-availability systems that have uptime guarantees and
|
where a hung tasks must be resolved ASAP.
|
|
Say N if unsure.
|
|
config 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
|
|
config WQ_WATCHDOG
|
bool "Detect Workqueue Stalls"
|
depends on DEBUG_KERNEL
|
help
|
Say Y here to enable stall detection on workqueues. If a
|
worker pool doesn't make forward progress on a pending work
|
item for over a given amount of time, 30s by default, a
|
warning message is printed along with dump of workqueue
|
state. This can be configured through kernel parameter
|
"workqueue.watchdog_thresh" and its sysfs counterpart.
|
|
config TEST_LOCKUP
|
tristate "Test module to generate lockups"
|
depends on m
|
help
|
This builds the "test_lockup" module that helps to make sure
|
that watchdogs and lockup detectors are working properly.
|
|
Depending on module parameters it could emulate soft or hard
|
lockup, "hung task", or locking arbitrary lock for a long time.
|
Also it could generate series of lockups with cooling-down periods.
|
|
If unsure, say N.
|
|
endmenu # "Debug lockups and hangs"
|
|
menu "Scheduler Debugging"
|
|
config SCHED_DEBUG
|
bool "Collect scheduler debugging info"
|
depends on DEBUG_KERNEL && PROC_FS
|
default y
|
help
|
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.
|
|
config SCHED_INFO
|
bool
|
default n
|
|
config SCHEDSTATS
|
bool "Collect scheduler statistics"
|
depends on DEBUG_KERNEL && PROC_FS
|
select SCHED_INFO
|
help
|
If you say Y here, additional code will be inserted into the
|
scheduler and related routines to collect statistics about
|
scheduler behavior and provide them in /proc/schedstat. These
|
stats may be useful for both tuning and debugging the scheduler
|
If you aren't debugging the scheduler or trying to tune a specific
|
application, you can say N to avoid the very slight overhead
|
this adds.
|
|
endmenu
|
|
config DEBUG_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.
|
|
config DEBUG_PREEMPT
|
bool "Debug preemptible kernel"
|
depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
|
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.
|
|
menu "Lock Debugging (spinlocks, mutexes, etc...)"
|
|
config LOCK_DEBUGGING_SUPPORT
|
bool
|
depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
|
default y
|
|
config PROVE_LOCKING
|
bool "Lock debugging: prove locking correctness"
|
depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
|
select LOCKDEP
|
select DEBUG_SPINLOCK
|
select DEBUG_MUTEXES
|
select DEBUG_RT_MUTEXES if RT_MUTEXES
|
select DEBUG_RWSEMS
|
select DEBUG_WW_MUTEX_SLOWPATH
|
select DEBUG_LOCK_ALLOC
|
select PREEMPT_COUNT if !ARCH_NO_PREEMPT
|
select TRACE_IRQFLAGS
|
default n
|
help
|
This feature enables the kernel to prove that all locking
|
that occurs in the kernel runtime is mathematically
|
correct: that under no circumstance could an arbitrary (and
|
not yet triggered) combination of observed locking
|
sequences (on an arbitrary number of CPUs, running an
|
arbitrary number of tasks and interrupt contexts) cause a
|
deadlock.
|
|
In short, this feature enables the kernel to report locking
|
related deadlocks before they actually occur.
|
|
The proof does not depend on how hard and complex a
|
deadlock scenario would be to trigger: how many
|
participant CPUs, tasks and irq-contexts would be needed
|
for it to trigger. The proof also does not depend on
|
timing: if a race and a resulting deadlock is possible
|
theoretically (no matter how unlikely the race scenario
|
is), it will be proven so and will immediately be
|
reported by the kernel (once the event is observed that
|
makes the deadlock theoretically possible).
|
|
If a deadlock is impossible (i.e. the locking rules, as
|
observed by the kernel, are mathematically correct), the
|
kernel reports nothing.
|
|
NOTE: this feature can also be enabled for rwlocks, mutexes
|
and rwsems - in which case all dependencies between these
|
different locking variants are observed and mapped too, and
|
the proof of observed correctness is also maintained for an
|
arbitrary combination of these separate locking variants.
|
|
For more details, see Documentation/locking/lockdep-design.rst.
|
|
config PROVE_RAW_LOCK_NESTING
|
bool "Enable raw_spinlock - spinlock nesting checks"
|
depends on PROVE_LOCKING
|
default n
|
help
|
Enable the raw_spinlock vs. spinlock nesting checks which ensure
|
that the lock nesting rules for PREEMPT_RT enabled kernels are
|
not violated.
|
|
NOTE: There are known nesting problems. So if you enable this
|
option expect lockdep splats until these problems have been fully
|
addressed which is work in progress. This config switch allows to
|
identify and analyze these problems. It will be removed and the
|
check permanentely enabled once the main issues have been fixed.
|
|
If unsure, select N.
|
|
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
|
|
For more details, see Documentation/locking/lockstat.rst
|
|
This also enables lock events required by "perf lock",
|
subcommand of perf.
|
If you want to use "perf lock", you also need to turn on
|
CONFIG_EVENT_TRACING.
|
|
CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
|
(CONFIG_LOCKDEP defines "acquire" and "release" events.)
|
|
config DEBUG_RT_MUTEXES
|
bool "RT Mutex debugging, deadlock detection"
|
depends on DEBUG_KERNEL && RT_MUTEXES
|
help
|
This allows rt mutex semantics violations and rt mutex related
|
deadlocks (lockups) to be detected and reported automatically.
|
|
config DEBUG_SPINLOCK
|
bool "Spinlock and rw-lock debugging: basic checks"
|
depends on DEBUG_KERNEL
|
select UNINLINE_SPIN_UNLOCK
|
help
|
Say Y here and build SMP to catch missing spinlock initialization
|
and certain other kinds of spinlock errors commonly made. This is
|
best used in conjunction with the NMI watchdog so that spinlock
|
deadlocks are also debuggable.
|
|
config DEBUG_MUTEXES
|
bool "Mutex debugging: basic checks"
|
depends on DEBUG_KERNEL
|
help
|
This feature allows mutex semantics violations to be detected and
|
reported.
|
|
config DEBUG_WW_MUTEX_SLOWPATH
|
bool "Wait/wound mutex debugging: Slowpath testing"
|
depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
|
select DEBUG_LOCK_ALLOC
|
select DEBUG_SPINLOCK
|
select DEBUG_MUTEXES
|
help
|
This feature enables slowpath testing for w/w mutex users by
|
injecting additional -EDEADLK wound/backoff cases. Together with
|
the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
|
will test all possible w/w mutex interface abuse with the
|
exception of simply not acquiring all the required locks.
|
Note that this feature can introduce significant overhead, so
|
it really should not be enabled in a production or distro kernel,
|
even a debug kernel. If you are a driver writer, enable it. If
|
you are a distro, do not.
|
|
config DEBUG_RWSEMS
|
bool "RW Semaphore debugging: basic checks"
|
depends on DEBUG_KERNEL
|
help
|
This debugging feature allows mismatched rw semaphore locks
|
and unlocks to be detected and reported.
|
|
config DEBUG_LOCK_ALLOC
|
bool "Lock debugging: detect incorrect freeing of live locks"
|
depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
|
select DEBUG_SPINLOCK
|
select DEBUG_MUTEXES
|
select DEBUG_RT_MUTEXES if RT_MUTEXES
|
select LOCKDEP
|
help
|
This feature will check whether any held lock (spinlock, rwlock,
|
mutex or rwsem) is incorrectly freed by the kernel, via any of the
|
memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
|
vfree(), etc.), whether a live lock is incorrectly reinitialized via
|
spin_lock_init()/mutex_init()/etc., or whether there is any lock
|
held during task exit.
|
|
config LOCKDEP
|
bool
|
depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
|
select STACKTRACE
|
select KALLSYMS
|
select KALLSYMS_ALL
|
|
config LOCKDEP_SMALL
|
bool
|
|
config LOCKDEP_BITS
|
int "Bitsize for MAX_LOCKDEP_ENTRIES"
|
depends on LOCKDEP && !LOCKDEP_SMALL
|
range 10 30
|
default 15
|
help
|
Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
|
|
config LOCKDEP_CHAINS_BITS
|
int "Bitsize for MAX_LOCKDEP_CHAINS"
|
depends on LOCKDEP && !LOCKDEP_SMALL
|
range 10 30
|
default 16
|
help
|
Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
|
|
config LOCKDEP_STACK_TRACE_BITS
|
int "Bitsize for MAX_STACK_TRACE_ENTRIES"
|
depends on LOCKDEP && !LOCKDEP_SMALL
|
range 10 30
|
default 19
|
help
|
Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
|
|
config LOCKDEP_STACK_TRACE_HASH_BITS
|
int "Bitsize for STACK_TRACE_HASH_SIZE"
|
depends on LOCKDEP && !LOCKDEP_SMALL
|
range 10 30
|
default 14
|
help
|
Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
|
|
config LOCKDEP_CIRCULAR_QUEUE_BITS
|
int "Bitsize for elements in circular_queue struct"
|
depends on LOCKDEP
|
range 10 30
|
default 12
|
help
|
Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
|
|
config DEBUG_LOCKDEP
|
bool "Lock dependency engine debugging"
|
depends on DEBUG_KERNEL && LOCKDEP
|
help
|
If you say Y here, the lock dependency engine will do
|
additional runtime checks to debug itself, at the price
|
of more runtime overhead.
|
|
config DEBUG_ATOMIC_SLEEP
|
bool "Sleep inside atomic section checking"
|
select PREEMPT_COUNT
|
depends on DEBUG_KERNEL
|
depends on !ARCH_NO_PREEMPT
|
help
|
If you say Y here, various routines which may sleep will become very
|
noisy if they are called inside atomic sections: when a spinlock is
|
held, inside an rcu read side critical section, inside preempt disabled
|
sections, inside an interrupt, etc...
|
|
config DEBUG_LOCKING_API_SELFTESTS
|
bool "Locking API boot-time self-tests"
|
depends on DEBUG_KERNEL && !PREEMPT_RT
|
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.
|
|
config LOCK_TORTURE_TEST
|
tristate "torture tests for locking"
|
depends on DEBUG_KERNEL
|
select TORTURE_TEST
|
help
|
This option provides a kernel module that runs torture tests
|
on kernel locking primitives. The kernel module may be built
|
after the fact on the running kernel to be tested, if desired.
|
|
Say Y here if you want kernel locking-primitive torture tests
|
to be built into the kernel.
|
Say M if you want these torture tests to build as a module.
|
Say N if you are unsure.
|
|
config WW_MUTEX_SELFTEST
|
tristate "Wait/wound mutex selftests"
|
help
|
This option provides a kernel module that runs tests on the
|
on the struct ww_mutex locking API.
|
|
It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
|
with this test harness.
|
|
Say M if you want these self tests to build as a module.
|
Say N if you are unsure.
|
|
config SCF_TORTURE_TEST
|
tristate "torture tests for smp_call_function*()"
|
depends on DEBUG_KERNEL
|
select TORTURE_TEST
|
help
|
This option provides a kernel module that runs torture tests
|
on the smp_call_function() family of primitives. The kernel
|
module may be built after the fact on the running kernel to
|
be tested, if desired.
|
|
config CSD_LOCK_WAIT_DEBUG
|
bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
|
depends on DEBUG_KERNEL
|
depends on 64BIT
|
default n
|
help
|
This option enables debug prints when CPUs are slow to respond
|
to the smp_call_function*() IPI wrappers. These debug prints
|
include the IPI handler function currently executing (if any)
|
and relevant stack traces.
|
|
endmenu # lock debugging
|
|
config TRACE_IRQFLAGS
|
depends on TRACE_IRQFLAGS_SUPPORT
|
bool
|
help
|
Enables hooks to interrupt enabling and disabling for
|
either tracing or lock debugging.
|
|
config TRACE_IRQFLAGS_NMI
|
def_bool y
|
depends on TRACE_IRQFLAGS
|
depends on TRACE_IRQFLAGS_NMI_SUPPORT
|
|
config STACKTRACE
|
bool "Stack backtrace support"
|
depends on STACKTRACE_SUPPORT
|
help
|
This option causes the kernel to create a /proc/pid/stack for
|
every process, showing its current stack trace.
|
It is also used by various kernel debugging features that require
|
stack trace generation.
|
|
config WARN_ALL_UNSEEDED_RANDOM
|
bool "Warn for all uses of unseeded randomness"
|
default n
|
help
|
Some parts of the kernel contain bugs relating to their use of
|
cryptographically secure random numbers before it's actually possible
|
to generate those numbers securely. This setting ensures that these
|
flaws don't go unnoticed, by enabling a message, should this ever
|
occur. This will allow people with obscure setups to know when things
|
are going wrong, so that they might contact developers about fixing
|
it.
|
|
Unfortunately, on some models of some architectures getting
|
a fully seeded CRNG is extremely difficult, and so this can
|
result in dmesg getting spammed for a surprisingly long
|
time. This is really bad from a security perspective, and
|
so architecture maintainers really need to do what they can
|
to get the CRNG seeded sooner after the system is booted.
|
However, since users cannot do anything actionable to
|
address this, by default this option is disabled.
|
|
Say Y here if you want to receive warnings for all uses of
|
unseeded randomness. This will be of use primarily for
|
those developers interested in improving the security of
|
Linux kernels running on their architecture (or
|
subarchitecture).
|
|
config DEBUG_KOBJECT
|
bool "kobject debugging"
|
depends on DEBUG_KERNEL
|
help
|
If you say Y here, some extra kobject debugging messages will be sent
|
to the syslog.
|
|
config DEBUG_KOBJECT_RELEASE
|
bool "kobject release debugging"
|
depends on DEBUG_OBJECTS_TIMERS
|
help
|
kobjects are reference counted objects. This means that their
|
last reference count put is not predictable, and the kobject can
|
live on past the point at which a driver decides to drop 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.
|
|
config HAVE_DEBUG_BUGVERBOSE
|
bool
|
|
menu "Debug kernel data structures"
|
|
config DEBUG_LIST
|
bool "Debug linked list manipulation"
|
depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
|
help
|
Enable this to turn on extended checks in the linked-list
|
walking routines.
|
|
If unsure, say N.
|
|
config DEBUG_PLIST
|
bool "Debug priority linked list manipulation"
|
depends on DEBUG_KERNEL
|
help
|
Enable this to turn on extended checks in the priority-ordered
|
linked-list (plist) walking routines. This checks the entire
|
list multiple times during each manipulation.
|
|
If unsure, say N.
|
|
config DEBUG_SG
|
bool "Debug SG table operations"
|
depends on DEBUG_KERNEL
|
help
|
Enable this to turn on checks on scatter-gather tables. This can
|
help find problems with drivers that do not properly initialize
|
their sg tables.
|
|
If unsure, say N.
|
|
config DEBUG_NOTIFIERS
|
bool "Debug notifier call chains"
|
depends on DEBUG_KERNEL
|
help
|
Enable this to turn on sanity checking for notifier call chains.
|
This is most useful for kernel developers to make sure that
|
modules properly unregister themselves from notifier chains.
|
This is a relatively cheap check but if you care about maximum
|
performance, say N.
|
|
config 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.
|
|
endmenu
|
|
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.
|
|
source "kernel/rcu/Kconfig.debug"
|
|
config DEBUG_WQ_FORCE_RR_CPU
|
bool "Force round-robin CPU selection for unbound work items"
|
depends on DEBUG_KERNEL
|
default n
|
help
|
Workqueue used to implicitly guarantee that work items queued
|
without explicit CPU specified are put on the local CPU. This
|
guarantee is no longer true and while local CPU is still
|
preferred work items may be put on foreign CPUs. Kernel
|
parameter "workqueue.debug_force_rr_cpu" is added to force
|
round-robin CPU selection to flush out usages which depend on the
|
now broken guarantee. This config option enables the debug
|
feature by default. When enabled, memory and cache locality will
|
be impacted.
|
|
config DEBUG_BLOCK_EXT_DEVT
|
bool "Force extended block device numbers and spread them"
|
depends on DEBUG_KERNEL
|
depends on BLOCK
|
default n
|
help
|
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.
|
|
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.
|
|
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.
|
|
Say N if you are unsure.
|
|
config CPU_HOTPLUG_STATE_CONTROL
|
bool "Enable CPU hotplug state control"
|
depends on DEBUG_KERNEL
|
depends on HOTPLUG_CPU
|
default n
|
help
|
Allows to write steps between "offline" and "online" to the CPUs
|
sysfs target file so states can be stepped granular. This is a debug
|
option for now as the hotplug machinery cannot be stopped and
|
restarted at arbitrary points yet.
|
|
Say N if your are unsure.
|
|
config LATENCYTOP
|
bool "Latency measuring infrastructure"
|
depends on DEBUG_KERNEL
|
depends on STACKTRACE_SUPPORT
|
depends on PROC_FS
|
depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
|
select KALLSYMS
|
select KALLSYMS_ALL
|
select STACKTRACE
|
select SCHEDSTATS
|
select SCHED_DEBUG
|
help
|
Enable this option if you want to use the LatencyTOP tool
|
to find out which userspace is blocking on what kernel operations.
|
|
source "kernel/trace/Kconfig"
|
|
config PROVIDE_OHCI1394_DMA_INIT
|
bool "Remote debugging over FireWire early on boot"
|
depends on PCI && X86
|
help
|
If you want to debug problems which hang or crash the kernel early
|
on boot and the crashing machine has a FireWire port, you can use
|
this feature to remotely access the memory of the crashed machine
|
over FireWire. This employs remote DMA as part of the OHCI1394
|
specification which is now the standard for FireWire controllers.
|
|
With remote DMA, you can monitor the printk buffer remotely using
|
firescope and access all memory below 4GB using fireproxy from gdb.
|
Even controlling a kernel debugger is possible using remote DMA.
|
|
Usage:
|
|
If ohci1394_dma=early is used as boot parameter, it will initialize
|
all OHCI1394 controllers which are found in the PCI config space.
|
|
As all changes to the FireWire bus such as enabling and disabling
|
devices cause a bus reset and thereby disable remote DMA for all
|
devices, be sure to have the cable plugged and FireWire enabled on
|
the debugging host before booting the debug target for debugging.
|
|
This code (~1k) is freed after boot. By then, the firewire stack
|
in charge of the OHCI-1394 controllers should be used instead.
|
|
See Documentation/core-api/debugging-via-ohci1394.rst for more information.
|
|
source "samples/Kconfig"
|
|
config ARCH_HAS_DEVMEM_IS_ALLOWED
|
bool
|
|
config STRICT_DEVMEM
|
bool "Filter access to /dev/mem"
|
depends on MMU && DEVMEM
|
depends on ARCH_HAS_DEVMEM_IS_ALLOWED
|
default y if PPC || X86 || ARM64
|
help
|
If this option is disabled, you allow userspace (root) access to all
|
of memory, including kernel and userspace memory. Accidental
|
access to this is obviously disastrous, but specific access can
|
be used by people debugging the kernel. Note that with PAT support
|
enabled, even in this case there are restrictions on /dev/mem
|
use due to the cache aliasing requirements.
|
|
If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
|
file only allows userspace access to PCI space and the BIOS code and
|
data regions. This is sufficient for dosemu and X and all common
|
users of /dev/mem.
|
|
If in doubt, say Y.
|
|
config IO_STRICT_DEVMEM
|
bool "Filter I/O access to /dev/mem"
|
depends on STRICT_DEVMEM
|
help
|
If this option is disabled, you allow userspace (root) access to all
|
io-memory regardless of whether a driver is actively using that
|
range. Accidental access to this is obviously disastrous, but
|
specific access can be used by people debugging kernel drivers.
|
|
If this option is switched on, the /dev/mem file only allows
|
userspace access to *idle* io-memory ranges (see /proc/iomem) This
|
may break traditional users of /dev/mem (dosemu, legacy X, etc...)
|
if the driver using a given range cannot be disabled.
|
|
If in doubt, say Y.
|
|
menu "$(SRCARCH) Debugging"
|
|
source "arch/$(SRCARCH)/Kconfig.debug"
|
|
endmenu
|
|
menu "Kernel Testing and Coverage"
|
|
source "lib/kunit/Kconfig"
|
|
config NOTIFIER_ERROR_INJECTION
|
tristate "Notifier error injection"
|
depends on DEBUG_KERNEL
|
select DEBUG_FS
|
help
|
This option provides the ability to inject artificial errors to
|
specified notifier chain callbacks. It is useful to test the error
|
handling of notifier call chain failures.
|
|
Say N if unsure.
|
|
config PM_NOTIFIER_ERROR_INJECT
|
tristate "PM notifier error injection module"
|
depends on PM && NOTIFIER_ERROR_INJECTION
|
default m if PM_DEBUG
|
help
|
This option provides the ability to inject artificial errors to
|
PM notifier chain callbacks. It is controlled through debugfs
|
interface /sys/kernel/debug/notifier-error-inject/pm
|
|
If the notifier call chain should be failed with some events
|
notified, write the error code to "actions/<notifier event>/error".
|
|
Example: Inject PM suspend error (-12 = -ENOMEM)
|
|
# cd /sys/kernel/debug/notifier-error-inject/pm/
|
# echo -12 > actions/PM_SUSPEND_PREPARE/error
|
# echo mem > /sys/power/state
|
bash: echo: write error: Cannot allocate memory
|
|
To compile this code as a module, choose M here: the module will
|
be called pm-notifier-error-inject.
|
|
If unsure, say N.
|
|
config OF_RECONFIG_NOTIFIER_ERROR_INJECT
|
tristate "OF reconfig notifier error injection module"
|
depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
|
help
|
This option provides the ability to inject artificial errors to
|
OF reconfig notifier chain callbacks. It is controlled
|
through debugfs interface under
|
/sys/kernel/debug/notifier-error-inject/OF-reconfig/
|
|
If the notifier call chain should be failed with some events
|
notified, write the error code to "actions/<notifier event>/error".
|
|
To compile this code as a module, choose M here: the module will
|
be called of-reconfig-notifier-error-inject.
|
|
If unsure, say N.
|
|
config NETDEV_NOTIFIER_ERROR_INJECT
|
tristate "Netdev notifier error injection module"
|
depends on NET && NOTIFIER_ERROR_INJECTION
|
help
|
This option provides the ability to inject artificial errors to
|
netdevice notifier chain callbacks. It is controlled through debugfs
|
interface /sys/kernel/debug/notifier-error-inject/netdev
|
|
If the notifier call chain should be failed with some events
|
notified, write the error code to "actions/<notifier event>/error".
|
|
Example: Inject netdevice mtu change error (-22 = -EINVAL)
|
|
# cd /sys/kernel/debug/notifier-error-inject/netdev
|
# echo -22 > actions/NETDEV_CHANGEMTU/error
|
# ip link set eth0 mtu 1024
|
RTNETLINK answers: Invalid argument
|
|
To compile this code as a module, choose M here: the module will
|
be called netdev-notifier-error-inject.
|
|
If unsure, say N.
|
|
config FUNCTION_ERROR_INJECTION
|
bool "Fault-injections of functions"
|
depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
|
help
|
Add fault injections into various functions that are annotated with
|
ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
|
value of theses functions. This is useful to test error paths of code.
|
|
If unsure, say N
|
|
config FAULT_INJECTION
|
bool "Fault-injection framework"
|
depends on DEBUG_KERNEL
|
help
|
Provide fault-injection framework.
|
For more details, see Documentation/fault-injection/.
|
|
config FAILSLAB
|
bool "Fault-injection capability for kmalloc"
|
depends on FAULT_INJECTION
|
depends on SLAB || SLUB
|
help
|
Provide fault-injection capability for kmalloc.
|
|
config FAIL_PAGE_ALLOC
|
bool "Fault-injection capability for alloc_pages()"
|
depends on FAULT_INJECTION
|
help
|
Provide fault-injection capability for alloc_pages().
|
|
config FAULT_INJECTION_USERCOPY
|
bool "Fault injection capability for usercopy functions"
|
depends on FAULT_INJECTION
|
help
|
Provides fault-injection capability to inject failures
|
in usercopy functions (copy_from_user(), get_user(), ...).
|
|
config FAIL_MAKE_REQUEST
|
bool "Fault-injection capability for disk IO"
|
depends on FAULT_INJECTION && BLOCK
|
help
|
Provide fault-injection capability for disk IO.
|
|
config FAIL_IO_TIMEOUT
|
bool "Fault-injection capability for faking disk interrupts"
|
depends on FAULT_INJECTION && BLOCK
|
help
|
Provide fault-injection capability on end IO handling. This
|
will make the block layer "forget" an interrupt as configured,
|
thus exercising the error handling.
|
|
Only works with drivers that use the generic timeout handling,
|
for others it wont do anything.
|
|
config FAIL_FUTEX
|
bool "Fault-injection capability for futexes"
|
select DEBUG_FS
|
depends on FAULT_INJECTION && FUTEX
|
help
|
Provide fault-injection capability for futexes.
|
|
config FAULT_INJECTION_DEBUG_FS
|
bool "Debugfs entries for fault-injection capabilities"
|
depends on FAULT_INJECTION && SYSFS && DEBUG_FS
|
help
|
Enable configuration of fault-injection capabilities via debugfs.
|
|
config FAIL_FUNCTION
|
bool "Fault-injection capability for functions"
|
depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
|
help
|
Provide function-based fault-injection capability.
|
This will allow you to override a specific function with a return
|
with given return value. As a result, function caller will see
|
an error value and have to handle it. This is useful to test the
|
error handling in various subsystems.
|
|
config FAIL_MMC_REQUEST
|
bool "Fault-injection capability for MMC IO"
|
depends on FAULT_INJECTION_DEBUG_FS && MMC
|
help
|
Provide fault-injection capability for MMC IO.
|
This will make the mmc core return data errors. This is
|
useful to test the error handling in the mmc block device
|
and to test how the mmc host driver handles retries from
|
the block device.
|
|
config FAULT_INJECTION_STACKTRACE_FILTER
|
bool "stacktrace filter for fault-injection capabilities"
|
depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
|
depends on !X86_64
|
select STACKTRACE
|
depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
|
help
|
Provide stacktrace filter for fault-injection capabilities
|
|
config ARCH_HAS_KCOV
|
bool
|
help
|
An architecture should select this when it can successfully
|
build and run with CONFIG_KCOV. This typically requires
|
disabling instrumentation for some early boot code.
|
|
config CC_HAS_SANCOV_TRACE_PC
|
def_bool $(cc-option,-fsanitize-coverage=trace-pc)
|
|
|
config KCOV
|
bool "Code coverage for fuzzing"
|
depends on ARCH_HAS_KCOV
|
depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
|
select DEBUG_FS
|
select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
|
select SKB_EXTENSIONS if NET
|
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.
|
|
For more details, see Documentation/dev-tools/kcov.rst.
|
|
config KCOV_ENABLE_COMPARISONS
|
bool "Enable comparison operands collection by KCOV"
|
depends on KCOV
|
depends on $(cc-option,-fsanitize-coverage=trace-cmp)
|
help
|
KCOV also exposes operands of every comparison in the instrumented
|
code along with operand sizes and PCs of the comparison instructions.
|
These operands can be used by fuzzing engines to improve the quality
|
of fuzzing coverage.
|
|
config KCOV_INSTRUMENT_ALL
|
bool "Instrument all code by default"
|
depends on KCOV
|
default y
|
help
|
If you are doing generic system call fuzzing (like e.g. syzkaller),
|
then you will want to instrument the whole kernel and you should
|
say y here. If you are doing more targeted fuzzing (like e.g.
|
filesystem fuzzing with AFL) then you will want to enable coverage
|
for more specific subsets of files, and should say n here.
|
|
config KCOV_IRQ_AREA_SIZE
|
hex "Size of interrupt coverage collection area in words"
|
depends on KCOV
|
default 0x40000
|
help
|
KCOV uses preallocated per-cpu areas to collect coverage from
|
soft interrupts. This specifies the size of those areas in the
|
number of unsigned long words.
|
|
menuconfig RUNTIME_TESTING_MENU
|
bool "Runtime Testing"
|
def_bool y
|
|
if RUNTIME_TESTING_MENU
|
|
config LKDTM
|
tristate "Linux Kernel Dump Test Tool Module"
|
depends on DEBUG_FS
|
help
|
This module enables testing of the different dumping mechanisms by
|
inducing system failures at predefined crash points.
|
If you don't need it: say N
|
Choose M here to compile this code as a module. The module will be
|
called lkdtm.
|
|
Documentation on how to use the module can be found in
|
Documentation/fault-injection/provoke-crashes.rst
|
|
config TEST_LIST_SORT
|
tristate "Linked list sorting test"
|
depends on DEBUG_KERNEL || m
|
help
|
Enable this to turn on 'list_sort()' function test. This test is
|
executed only once during system boot (so affects only boot time),
|
or at module load time.
|
|
If unsure, say N.
|
|
config TEST_MIN_HEAP
|
tristate "Min heap test"
|
depends on DEBUG_KERNEL || m
|
help
|
Enable this to turn on min heap function tests. This test is
|
executed only once during system boot (so affects only boot time),
|
or at module load time.
|
|
If unsure, say N.
|
|
config TEST_SORT
|
tristate "Array-based sort test"
|
depends on DEBUG_KERNEL || m
|
help
|
This option enables the self-test function of 'sort()' at boot,
|
or at module load time.
|
|
If unsure, say N.
|
|
config KPROBES_SANITY_TEST
|
bool "Kprobes sanity tests"
|
depends on DEBUG_KERNEL
|
depends on KPROBES
|
help
|
This option provides for testing basic kprobes functionality on
|
boot. Samples of kprobe and kretprobe are inserted and
|
verified for functionality.
|
|
Say N if you are unsure.
|
|
config BACKTRACE_SELF_TEST
|
tristate "Self test for the backtrace code"
|
depends on DEBUG_KERNEL
|
help
|
This option provides a kernel module that can be used to test
|
the kernel stack backtrace code. This option is not useful
|
for distributions or general kernels, but only for kernel
|
developers working on architecture code.
|
|
Note that if you want to also test saved backtraces, you will
|
have to enable STACKTRACE as well.
|
|
Say N if you are unsure.
|
|
config RBTREE_TEST
|
tristate "Red-Black tree test"
|
depends on DEBUG_KERNEL
|
help
|
A benchmark measuring the performance of the rbtree library.
|
Also includes rbtree invariant checks.
|
|
config REED_SOLOMON_TEST
|
tristate "Reed-Solomon library test"
|
depends on DEBUG_KERNEL || m
|
select REED_SOLOMON
|
select REED_SOLOMON_ENC16
|
select REED_SOLOMON_DEC16
|
help
|
This option enables the self-test function of rslib at boot,
|
or at module load time.
|
|
If unsure, say N.
|
|
config INTERVAL_TREE_TEST
|
tristate "Interval tree test"
|
depends on DEBUG_KERNEL
|
select INTERVAL_TREE
|
help
|
A benchmark measuring the performance of the interval tree library
|
|
config PERCPU_TEST
|
tristate "Per cpu operations test"
|
depends on m && DEBUG_KERNEL
|
help
|
Enable this option to build test module which validates per-cpu
|
operations.
|
|
If unsure, say N.
|
|
config ATOMIC64_SELFTEST
|
tristate "Perform an atomic64_t self-test"
|
help
|
Enable this option to test the atomic64_t functions at boot or
|
at module load time.
|
|
If unsure, say N.
|
|
config ASYNC_RAID6_TEST
|
tristate "Self test for hardware accelerated raid6 recovery"
|
depends on ASYNC_RAID6_RECOV
|
select ASYNC_MEMCPY
|
help
|
This is a one-shot self test that permutes through the
|
recovery of all the possible two disk failure scenarios for a
|
N-disk array. Recovery is performed with the asynchronous
|
raid6 recovery routines, and will optionally use an offload
|
engine if one is available.
|
|
If unsure, say N.
|
|
config TEST_HEXDUMP
|
tristate "Test functions located in the hexdump module at runtime"
|
|
config TEST_STRING_HELPERS
|
tristate "Test functions located in the string_helpers module at runtime"
|
|
config TEST_STRSCPY
|
tristate "Test strscpy*() family of functions at runtime"
|
|
config TEST_KSTRTOX
|
tristate "Test kstrto*() family of functions at runtime"
|
|
config TEST_PRINTF
|
tristate "Test printf() family of functions at runtime"
|
|
config TEST_BITMAP
|
tristate "Test bitmap_*() family of functions at runtime"
|
help
|
Enable this option to test the bitmap functions at boot.
|
|
If unsure, say N.
|
|
config TEST_UUID
|
tristate "Test functions located in the uuid module at runtime"
|
|
config TEST_XARRAY
|
tristate "Test the XArray code at runtime"
|
|
config TEST_OVERFLOW
|
tristate "Test check_*_overflow() functions at runtime"
|
|
config TEST_RHASHTABLE
|
tristate "Perform selftest on resizable hash table"
|
help
|
Enable this option to test the rhashtable functions at boot.
|
|
If unsure, say N.
|
|
config TEST_HASH
|
tristate "Perform selftest on hash functions"
|
help
|
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).
|
|
This is intended to help people writing architecture-specific
|
optimized versions. If unsure, say N.
|
|
config TEST_IDA
|
tristate "Perform selftest on IDA functions"
|
|
config TEST_PARMAN
|
tristate "Perform selftest on priority array manager"
|
depends on PARMAN
|
help
|
Enable this option to test priority array manager on boot
|
(or module load).
|
|
If unsure, say N.
|
|
config TEST_IRQ_TIMINGS
|
bool "IRQ timings selftest"
|
depends on IRQ_TIMINGS
|
help
|
Enable this option to test the irq timings code on boot.
|
|
If unsure, say N.
|
|
config TEST_LKM
|
tristate "Test module loading with 'hello world' module"
|
depends on m
|
help
|
This builds the "test_module" module that emits "Hello, world"
|
on printk when loaded. It is designed to be used for basic
|
evaluation of the module loading subsystem (for example when
|
validating module verification). It lacks any extra dependencies,
|
and will not normally be loaded by the system unless explicitly
|
requested by name.
|
|
If unsure, say N.
|
|
config TEST_BITOPS
|
tristate "Test module for compilation of bitops operations"
|
depends on m
|
help
|
This builds the "test_bitops" module that is much like the
|
TEST_LKM module except that it does a basic exercise of the
|
set/clear_bit macros and get_count_order/long to make sure there are
|
no compiler warnings from C=1 sparse checker or -Wextra
|
compilations. It has no dependencies and doesn't run or load unless
|
explicitly requested by name. for example: modprobe test_bitops.
|
|
If unsure, say N.
|
|
config TEST_VMALLOC
|
tristate "Test module for stress/performance analysis of vmalloc allocator"
|
default n
|
depends on MMU
|
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.
|
|
config TEST_USER_COPY
|
tristate "Test user/kernel boundary protections"
|
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.
|
|
config TEST_BPF
|
tristate "Test BPF filter functionality"
|
depends on m && NET
|
help
|
This builds the "test_bpf" module that runs various test vectors
|
against the BPF interpreter or BPF JIT compiler depending on the
|
current setting. This is in particular useful for BPF JIT compiler
|
development, but also to run regression tests against changes in
|
the interpreter code. It also enables test stubs for eBPF maps and
|
verifier used by user space verifier testsuite.
|
|
If unsure, say N.
|
|
config 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.
|
|
config FIND_BIT_BENCHMARK
|
tristate "Test find_bit functions"
|
help
|
This builds the "test_find_bit" module that measure find_*_bit()
|
functions performance.
|
|
If unsure, say N.
|
|
config TEST_FIRMWARE
|
tristate "Test firmware loading via userspace interface"
|
depends on FW_LOADER
|
help
|
This builds the "test_firmware" module that creates a userspace
|
interface for testing firmware loading. This can be used to
|
control the triggering of firmware loading without needing an
|
actual firmware-using device. The contents can be rechecked by
|
userspace.
|
|
If unsure, say N.
|
|
config TEST_SYSCTL
|
tristate "sysctl test driver"
|
depends on PROC_SYSCTL
|
help
|
This builds the "test_sysctl" module. This driver enables to test the
|
proc sysctl interfaces available to drivers safely without affecting
|
production knobs which might alter system functionality.
|
|
If unsure, say N.
|
|
config BITFIELD_KUNIT
|
tristate "KUnit test bitfield functions at runtime"
|
depends on KUNIT
|
help
|
Enable this option to test the bitfield functions at boot.
|
|
KUnit tests run during boot and output the results to the debug log
|
in TAP format (http://testanything.org/). Only useful for kernel devs
|
running the KUnit test harness, and not intended for inclusion into a
|
production build.
|
|
For more information on KUnit and unit tests in general please refer
|
to the KUnit documentation in Documentation/dev-tools/kunit/.
|
|
If unsure, say N.
|
|
config SYSCTL_KUNIT_TEST
|
tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
|
depends on KUNIT
|
default KUNIT_ALL_TESTS
|
help
|
This builds the proc sysctl unit test, which runs on boot.
|
Tests the API contract and implementation correctness of sysctl.
|
For more information on KUnit and unit tests in general please refer
|
to the KUnit documentation in Documentation/dev-tools/kunit/.
|
|
If unsure, say N.
|
|
config LIST_KUNIT_TEST
|
tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
|
depends on KUNIT
|
default KUNIT_ALL_TESTS
|
help
|
This builds the linked list KUnit test suite.
|
It tests that the API and basic functionality of the list_head type
|
and associated macros.
|
|
KUnit tests run during boot and output the results to the debug log
|
in TAP format (https://testanything.org/). Only useful for kernel devs
|
running the KUnit test harness, and not intended for inclusion into a
|
production build.
|
|
For more information on KUnit and unit tests in general please refer
|
to the KUnit documentation in Documentation/dev-tools/kunit/.
|
|
If unsure, say N.
|
|
config LINEAR_RANGES_TEST
|
tristate "KUnit test for linear_ranges"
|
depends on KUNIT
|
select LINEAR_RANGES
|
help
|
This builds the linear_ranges unit test, which runs on boot.
|
Tests the linear_ranges logic correctness.
|
For more information on KUnit and unit tests in general please refer
|
to the KUnit documentation in Documentation/dev-tools/kunit/.
|
|
If unsure, say N.
|
|
config BITS_TEST
|
tristate "KUnit test for bits.h"
|
depends on KUNIT
|
help
|
This builds the bits unit test.
|
Tests the logic of macros defined in bits.h.
|
For more information on KUnit and unit tests in general please refer
|
to the KUnit documentation in Documentation/dev-tools/kunit/.
|
|
If unsure, say N.
|
|
config TEST_UDELAY
|
tristate "udelay test driver"
|
help
|
This builds the "udelay_test" module that helps to make sure
|
that udelay() is working properly.
|
|
If unsure, say N.
|
|
config TEST_STATIC_KEYS
|
tristate "Test static keys"
|
depends on m
|
help
|
Test the static key interfaces.
|
|
If unsure, say N.
|
|
config TEST_KMOD
|
tristate "kmod stress tester"
|
depends on m
|
depends on NETDEVICES && NET_CORE && INET # for TUN
|
depends on BLOCK
|
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.
|
|
config TEST_DEBUG_VIRTUAL
|
tristate "Test CONFIG_DEBUG_VIRTUAL feature"
|
depends on DEBUG_VIRTUAL
|
help
|
Test the kernel's ability to detect incorrect calls to
|
virt_to_phys() done against the non-linear part of the
|
kernel's virtual address map.
|
|
If unsure, say N.
|
|
config TEST_MEMCAT_P
|
tristate "Test memcat_p() helper function"
|
help
|
Test the memcat_p() helper for correctly merging two
|
pointer arrays together.
|
|
If unsure, say N.
|
|
config TEST_LIVEPATCH
|
tristate "Test livepatching"
|
default n
|
depends on DYNAMIC_DEBUG
|
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.
|
|
config TEST_OBJAGG
|
tristate "Perform selftest on object aggreration manager"
|
default n
|
depends on OBJAGG
|
help
|
Enable this option to test object aggregation manager on boot
|
(or module load).
|
|
|
config TEST_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.
|
|
config TEST_MEMINIT
|
tristate "Test heap/page initialization"
|
help
|
Test if the kernel is zero-initializing heap and page allocations.
|
This can be useful to test init_on_alloc and init_on_free features.
|
|
If unsure, say N.
|
|
config TEST_HMM
|
tristate "Test HMM (Heterogeneous Memory Management)"
|
depends on TRANSPARENT_HUGEPAGE
|
depends on DEVICE_PRIVATE
|
select HMM_MIRROR
|
select MMU_NOTIFIER
|
help
|
This is a pseudo device driver solely for testing HMM.
|
Say M here if you want to build the HMM test module.
|
Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
|
|
If unsure, say N.
|
|
config TEST_FREE_PAGES
|
tristate "Test freeing pages"
|
help
|
Test that a memory leak does not occur due to a race between
|
freeing a block of pages and a speculative page reference.
|
Loading this module is safe if your kernel has the bug fixed.
|
If the bug is not fixed, it will leak gigabytes of memory and
|
probably OOM your system.
|
|
config TEST_FPU
|
tristate "Test floating point operations in kernel space"
|
depends on X86 && !KCOV_INSTRUMENT_ALL
|
help
|
Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
|
which will trigger a sequence of floating point operations. This is used
|
for self-testing floating point control register setting in
|
kernel_fpu_begin().
|
|
If unsure, say N.
|
|
endif # RUNTIME_TESTING_MENU
|
|
config MEMTEST
|
bool "Memtest"
|
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 HYPERV_TESTING
|
bool "Microsoft Hyper-V driver testing"
|
default n
|
depends on HYPERV && DEBUG_FS
|
help
|
Select this option to enable Hyper-V vmbus testing.
|
|
endmenu # "Kernel Testing and Coverage"
|
|
source "Documentation/Kconfig"
|
|
endmenu # Kernel hacking
|
