# SPDX-License-Identifier: GPL-2.0-only
menu "Kernel hacking"
menu "printk and dmesg options"
config [31mCONFIG_PRINTK_TIME[0m
bool "Show timing information on printks"
depends on [31mCONFIG_PRINTK[0m
help
Selecting this option causes time stamps of the printk()
messages to be added to the output of the syslog() system
call and at the console.
The timestamp is always recorded internally, and exported
to /dev/kmsg. This flag just specifies if the timestamp should
be included, not that the timestamp is recorded.
The behavior is also controlled by the kernel command line
parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
config [31mCONFIG_PRINTK_CALLER[0m
bool "Show caller information on printks"
depends on [31mCONFIG_PRINTK[0m
help
Selecting this option causes printk() to add a caller "thread id" (if
in task context) or a caller "processor id" (if not in task context)
to every message.
This option is intended for environments where multiple threads
concurrently call printk() for many times, for it is difficult to
interpret without knowing where these lines (or sometimes individual
line which was divided into multiple lines due to race) came from.
Since toggling after boot makes the code racy, currently there is
no option to enable/disable at the kernel command line parameter or
sysfs interface.
config [31mCONFIG_CONSOLE_LOGLEVEL_DEFAULT[0m
int "Default console loglevel (1-15)"
range 1 15
default "7"
help
Default loglevel to determine what will be printed on the console.
Setting a default here is equivalent to passing in loglevel=<x> in
the kernel bootargs. loglevel=<x> continues to override whatever
value is specified here as well.
Note: This does not affect the log level of un-prefixed printk()
usage in the kernel. That is controlled by the [31mCONFIG_MESSAGE_LOGLEVEL_DEFAULT[0m
option.
config [31mCONFIG_CONSOLE_LOGLEVEL_QUIET[0m
int "quiet console loglevel (1-15)"
range 1 15
default "4"
help
loglevel to use when "quiet" is passed on the kernel commandline.
When "quiet" is passed on the kernel commandline this loglevel
will be used as the loglevel. IOW passing "quiet" will be the
equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
config [31mCONFIG_MESSAGE_LOGLEVEL_DEFAULT[0m
int "Default message log level (1-7)"
range 1 7
default "4"
help
Default log level for printk statements with no specified priority.
This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
that are auditing their logs closely may want to set it to a lower
priority.
Note: This does not affect what message level gets printed on the console
by default. To change that, use loglevel=<x> in the kernel bootargs,
or pick a different [31mCONFIG_CONSOLE_LOGLEVEL_DEFAULT[0m configuration value.
config [31mCONFIG_BOOT_PRINTK_DELAY[0m
bool "Delay each boot printk message by N milliseconds"
depends on [31mCONFIG_DEBUG_KERNEL[0m && [31mCONFIG_PRINTK[0m && [31mCONFIG_GENERIC_CALIBRATE_DELAY[0m
help
This build option allows you to read kernel boot messages
by inserting a short delay after each one. The delay is
specified in milliseconds on the kernel command line,
using "boot_delay=N".
It is likely that you would also need to use "lpj=M" to preset
the "loops per jiffie" value.
See a previous boot log for the "lpj" value to use for your
system, and then set "lpj=M" before setting "boot_delay=N".
NOTE: Using this option may adversely affect [31mCONFIG_SMP[0m systems.
I.e., processors other than the first one may not boot up.
[31mCONFIG_BOOT_PRINTK_DELAY[0m also may cause [31mCONFIG_LOCKUP_DETECTOR[0m to detect
what it believes to be lockup conditions.
config [31mCONFIG_DYNAMIC_DEBUG[0m
bool "Enable dynamic printk() support"
default n
depends on [31mCONFIG_PRINTK[0m
depends on [31mCONFIG_DEBUG_FS[0m
help
Compiles debug level messages into the kernel, which would not
otherwise be available at runtime. These messages can then be
enabled/disabled based on various levels of scope - per source file,
function, module, format string, and line number. This mechanism
implicitly compiles in all pr_debug() and dev_dbg() calls, which
enlarges the kernel text size by about 2%.
If a source file is compiled with DEBUG flag set, any
pr_debug() calls in it are enabled by default, but can be
disabled at runtime as below. Note that DEBUG flag is
turned on by many CONFIG_*DEBUG* options.
Usage:
Dynamic debugging is controlled via the 'dynamic_debug/control' file,
which is contained in the 'debugfs' filesystem. Thus, the debugfs
filesystem must first be mounted before making use of this feature.
We refer the control file as: <debugfs>/dynamic_debug/control. This
file contains a list of the debug statements that can be enabled. The
format for each line of the file is:
filename:lineno [module]function flags format
filename : source file of the debug statement
lineno : line number of the debug statement
module : module that contains the debug statement
function : function that contains the debug statement
flags : '=p' means the line is turned 'on' for printing
format : the format used for the debug statement
From a live system:
nullarbor:~ # cat <debugfs>/dynamic_debug/control
# filename:lineno [module]function flags format
fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
Example usage:
// enable the message at line 1603 of file svcsock.c
nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
<debugfs>/dynamic_debug/control
// enable all the messages in file svcsock.c
nullarbor:~ # echo -n 'file svcsock.c +p' >
<debugfs>/dynamic_debug/control
// enable all the messages in the NFS server module
nullarbor:~ # echo -n 'module nfsd +p' >
<debugfs>/dynamic_debug/control
// enable all 12 messages in the function svc_process()
nullarbor:~ # echo -n 'func svc_process +p' >
<debugfs>/dynamic_debug/control
// disable all 12 messages in the function svc_process()
nullarbor:~ # echo -n 'func svc_process -p' >
<debugfs>/dynamic_debug/control
See Documentation/admin-guide/dynamic-debug-howto.rst for additional
information.
endmenu # "printk and dmesg options"
menu "Compile-time checks and compiler options"
config [31mCONFIG_DEBUG_INFO[0m
bool "Compile the kernel with debug info"
depends on [31mCONFIG_DEBUG_KERNEL[0m && ![31mCONFIG_COMPILE_TEST[0m
help
If you say Y here the resulting kernel image will include
debugging info resulting in a larger kernel image.
This adds debug symbols to the kernel and modules (gcc -g), and
is needed if you intend to use kernel crashdump or binary object
tools like crash, kgdb, LKCD, gdb, etc on the kernel.
Say Y here only if you plan to debug the kernel.
If unsure, say N.
config [31mCONFIG_DEBUG_INFO_REDUCED[0m
bool "Reduce debugging information"
depends on [31mCONFIG_DEBUG_INFO[0m
help
If you say Y here gcc is instructed to generate less debugging
information for structure types. This means that tools that
need full debugging information (like kgdb or systemtap) won't
be happy. But if you merely need debugging information to
resolve line numbers there is no loss. Advantage is that
build directory object sizes shrink dramatically over a full
[31mCONFIG_DEBUG_INFO[0m build and compile times are reduced too.
Only works with newer gcc versions.
config [31mCONFIG_DEBUG_INFO_SPLIT[0m
bool "Produce split debuginfo in .dwo files"
depends on [31mCONFIG_DEBUG_INFO[0m
depends on $(cc-option,-gsplit-dwarf)
help
Generate debug info into separate .dwo files. This significantly
reduces the build directory size for builds with [31mCONFIG_DEBUG_INFO[0m,
because it stores the information only once on disk in .dwo
files instead of multiple times in object files and executables.
In addition the debug information is also compressed.
Requires recent gcc (4.7+) and recent gdb/binutils.
Any tool that packages or reads debug information would need
to know about the .dwo files and include them.
Incompatible with older versions of ccache.
config [31mCONFIG_DEBUG_INFO_DWARF4[0m
bool "Generate dwarf4 debuginfo"
depends on [31mCONFIG_DEBUG_INFO[0m
depends on $(cc-option,-gdwarf-4)
help
Generate dwarf4 debug info. This requires recent versions
of gcc and gdb. It makes the debug information larger.
But it significantly improves the success of resolving
variables in gdb on optimized code.
config [31mCONFIG_DEBUG_INFO_BTF[0m
bool "Generate BTF typeinfo"
depends on [31mCONFIG_DEBUG_INFO[0m
help
Generate deduplicated BTF type information from DWARF debug info.
Turning this on expects presence of pahole tool, which will convert
DWARF type info into equivalent deduplicated BTF type info.
config [31mCONFIG_GDB_SCRIPTS[0m
bool "Provide GDB scripts for kernel debugging"
depends on [31mCONFIG_DEBUG_INFO[0m
help
This creates the required links to GDB helper scripts in the
build directory. If you load vmlinux into gdb, the helper
scripts will be automatically imported by gdb as well, and
additional functions are available to analyze a Linux kernel
instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
for further details.
config [31mCONFIG_ENABLE_MUST_CHECK[0m
bool "Enable __must_check logic"
default y
help
Enable the __must_check logic in the kernel build. Disable this to
suppress the "warning: ignoring return value of 'foo', declared with
attribute warn_unused_result" messages.
config [31mCONFIG_FRAME_WARN[0m
int "Warn for stack frames larger than (needs gcc 4.4)"
range 0 8192
default 2048 if [31mCONFIG_GCC_PLUGIN_LATENT_ENTROPY[0m
default 1280 if (![31mCONFIG_64BIT[0m && [31mCONFIG_PARISC[0m)
default 1024 if (![31mCONFIG_64BIT[0m && ![31mCONFIG_PARISC[0m)
default 2048 if [31mCONFIG_64BIT[0m
help
Tell gcc to warn at build time for stack frames larger than this.
Setting this too low will cause a lot of warnings.
Setting it to 0 disables the warning.
Requires gcc 4.4
config [31mCONFIG_STRIP_ASM_SYMS[0m
bool "Strip assembler-generated symbols during link"
default n
help
Strip internal assembler-generated symbols during a link (symbols
that look like '.Lxxx') so they don't pollute the output of
get_wchan() and suchlike.
config [31mCONFIG_READABLE_ASM[0m
bool "Generate readable assembler code"
depends on [31mCONFIG_DEBUG_KERNEL[0m
help
Disable some compiler optimizations that tend to generate human unreadable
assembler output. This may make the kernel slightly slower, but it helps
to keep kernel developers who have to stare a lot at assembler listings
sane.
config [31mCONFIG_DEBUG_FS[0m
bool "Debug Filesystem"
help
debugfs is a virtual file system that kernel developers use to put
debugging files into. Enable this option to be able to read and
write to these files.
For detailed documentation on the debugfs API, see
Documentation/filesystems/.
If unsure, say N.
config [31mCONFIG_HEADERS_INSTALL[0m
bool "Install uapi headers to usr/include"
depends on ![31mCONFIG_UML[0m
help
This option will install uapi headers (headers exported to user-space)
into the usr/include directory for use during the kernel build.
This is unneeded for building the kernel itself, but needed for some
user-space program samples. It is also needed by some features such
as uapi header sanity checks.
config [31mCONFIG_HEADERS_CHECK[0m
bool "Run sanity checks on uapi headers when building 'all'"
depends on [31mCONFIG_HEADERS_INSTALL[0m
help
This option will run basic sanity checks on uapi headers when
building the 'all' target, for example, ensure that they do not
attempt to include files which were not exported, etc.
If you're making modifications to header files which are
relevant for userspace, say 'Y'.
config [31mCONFIG_OPTIMIZE_INLINING[0m
def_bool y
help
This option determines if the kernel forces gcc to inline the functions
developers have marked 'inline'. Doing so takes away freedom from gcc to
do what it thinks is best, which is desirable for the gcc 3.x series of
compilers. The gcc 4.x series have a rewritten inlining algorithm and
enabling this option will generate a smaller kernel there. Hopefully
this algorithm is so good that allowing gcc 4.x and above to make the
decision will become the default in the future. Until then this option
is there to test gcc for this.
config [31mCONFIG_DEBUG_SECTION_MISMATCH[0m
bool "Enable full Section mismatch analysis"
help
The section mismatch analysis checks if there are illegal
references from one section to another section.
During linktime or runtime, some sections are dropped;
any use of code/data previously in these sections would
most likely result in an oops.
In the code, functions and variables are annotated with
__init,, etc. (see the full list in include/linux/init.h),
which results in the code/data being placed in specific sections.
The section mismatch analysis is always performed after a full
kernel build, and enabling this option causes the following
additional step to occur:
- Add the option -fno-inline-functions-called-once to gcc commands.
When inlining a function annotated with __init in a non-init
function, we would lose the section information and thus
the analysis would not catch the illegal reference.
This option tells gcc to inline less (but it does result in
a larger kernel).
config [31mCONFIG_SECTION_MISMATCH_WARN_ONLY[0m
bool "Make section mismatch errors non-fatal"
default y
help
If you say N here, the build process will fail if there are any
section mismatch, instead of just throwing warnings.
If unsure, say Y.
#
# Select this config option from the architecture Kconfig, if it
# is preferred to always offer frame pointers as a config
# option on the architecture (regardless of KERNEL_DEBUG):
#
config [31mCONFIG_ARCH_WANT_FRAME_POINTERS[0m
bool
config [31mCONFIG_FRAME_POINTER[0m
bool "Compile the kernel with frame pointers"
depends on [31mCONFIG_DEBUG_KERNEL[0m && ([31mCONFIG_M68K[0m || [31mCONFIG_UML[0m || [31mCONFIG_SUPERH[0m) || [31mCONFIG_ARCH_WANT_FRAME_POINTERS[0m
default y if ([31mCONFIG_DEBUG_INFO[0m && [31mCONFIG_UML[0m) || [31mCONFIG_ARCH_WANT_FRAME_POINTERS[0m
help
If you say Y here the resulting kernel image will be slightly
larger and slower, but it gives very useful debugging information
in case of kernel bugs. (precise oopses/stacktraces/warnings)
config [31mCONFIG_STACK_VALIDATION[0m
bool "Compile-time stack metadata validation"
depends on [31mCONFIG_HAVE_STACK_VALIDATION[0m
default n
help
Add compile-time checks to validate stack metadata, including frame
pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
that runtime stack traces are more reliable.
This is also a prerequisite for generation of ORC unwind data, which
is needed for CONFIG_UNWINDER_ORC.
For more information, see
tools/objtool/Documentation/stack-validation.txt.
config [31mCONFIG_DEBUG_FORCE_WEAK_PER_CPU[0m
bool "Force weak per-cpu definitions"
depends on [31mCONFIG_DEBUG_KERNEL[0m
help
s390 and alpha require percpu variables in modules to be
defined weak to work around addressing range issue which
puts the following two restrictions on percpu variable
definitions.
1. percpu symbols must be unique whether static or not
2. percpu variables can't be defined inside a function
To ensure that generic code follows the above rules, this
option forces all percpu variables to be defined as weak.
endmenu # "Compiler options"
config [31mCONFIG_MAGIC_SYSRQ[0m
bool "Magic SysRq key"
depends on ![31mCONFIG_UML[0m
help
If you say Y here, you will have some control over the system even
if the system crashes for example during kernel debugging (e.g., you
will be able to flush the buffer cache to disk, reboot the system
immediately or dump some status information). This is accomplished
by pressing various keys while holding SysRq (Alt+PrintScreen). It
also works on a serial console (on PC hardware at least), if you
send a BREAK and then within 5 seconds a command keypress. The
keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
Don't say Y unless you really know what this hack does.
config [31mCONFIG_MAGIC_SYSRQ_DEFAULT_ENABLE[0m
hex "Enable magic SysRq key functions by default"
depends on [31mCONFIG_MAGIC_SYSRQ[0m
default 0x1
help
Specifies which SysRq key functions are enabled by default.
This may be set to 1 or 0 to enable or disable them all, or
to a bitmask as described in Documentation/admin-guide/sysrq.rst.
config [31mCONFIG_MAGIC_SYSRQ_SERIAL[0m
bool "Enable magic SysRq key over serial"
depends on [31mCONFIG_MAGIC_SYSRQ[0m
default y
help
Many embedded boards have a disconnected TTL level serial which can
generate some garbage that can lead to spurious false sysrq detects.
This option allows you to decide whether you want to enable the
magic SysRq key.
config [31mCONFIG_DEBUG_KERNEL[0m
bool "Kernel debugging"
help
Say Y here if you are developing drivers or trying to debug and
identify kernel problems.
config [31mCONFIG_DEBUG_MISC[0m
bool "Miscellaneous debug code"
default [31mCONFIG_DEBUG_KERNEL[0m
depends on [31mCONFIG_DEBUG_KERNEL[0m
help
Say Y here if you need to enable miscellaneous debug code that should
be under a more specific debug option but isn't.
menu "Memory Debugging"
source "mm/Kconfig.debug"
config [31mCONFIG_DEBUG_OBJECTS[0m
bool "Debug object operations"
depends on [31mCONFIG_DEBUG_KERNEL[0m
help
If you say Y here, additional code will be inserted into the
kernel to track the life time of various objects and validate
the operations on those objects.
config [31mCONFIG_DEBUG_OBJECTS_SELFTEST[0m
bool "Debug objects selftest"
depends on [31mCONFIG_DEBUG_OBJECTS[0m
help
This enables the selftest of the object debug code.
config [31mCONFIG_DEBUG_OBJECTS_FREE[0m
bool "Debug objects in freed memory"
depends on [31mCONFIG_DEBUG_OBJECTS[0m
help
This enables checks whether a k/v free operation frees an area
which contains an object which has not been deactivated
properly. This can make kmalloc/kfree-intensive workloads
much slower.
config [31mCONFIG_DEBUG_OBJECTS_TIMERS[0m
bool "Debug timer objects"
depends on [31mCONFIG_DEBUG_OBJECTS[0m
help
If you say Y here, additional code will be inserted into the
timer routines to track the life time of timer objects and
validate the timer operations.
config [31mCONFIG_DEBUG_OBJECTS_WORK[0m
bool "Debug work objects"
depends on [31mCONFIG_DEBUG_OBJECTS[0m
help
If you say Y here, additional code will be inserted into the
work queue routines to track the life time of work objects and
validate the work operations.
config [31mCONFIG_DEBUG_OBJECTS_RCU_HEAD[0m
bool "Debug RCU callbacks objects"
depends on [31mCONFIG_DEBUG_OBJECTS[0m
help
Enable this to turn on debugging of RCU list heads (call_rcu() usage).
config [31mCONFIG_DEBUG_OBJECTS_PERCPU_COUNTER[0m
bool "Debug percpu counter objects"
depends on [31mCONFIG_DEBUG_OBJECTS[0m
help
If you say Y here, additional code will be inserted into the
percpu counter routines to track the life time of percpu counter
objects and validate the percpu counter operations.
config [31mCONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT[0m
int "debug_objects bootup default value (0-1)"
range 0 1
default "1"
depends on [31mCONFIG_DEBUG_OBJECTS[0m
help
Debug objects boot parameter default value
config [31mCONFIG_DEBUG_SLAB[0m
bool "Debug slab memory allocations"
depends on [31mCONFIG_DEBUG_KERNEL[0m && [31mCONFIG_SLAB[0m
help
Say Y here to have the kernel do limited verification on memory
allocation as well as poisoning memory on free to catch use of freed
memory. This can make kmalloc/kfree-intensive workloads much slower.
config [31mCONFIG_SLUB_DEBUG_ON[0m
bool "SLUB debugging on by default"
depends on [31mCONFIG_SLUB[0m && [31mCONFIG_SLUB_DEBUG[0m
default n
help
Boot with debugging on by default. [31mCONFIG_SLUB[0m boots by default with
the runtime debug capabilities switched off. Enabling this is
equivalent to specifying the "slub_debug" parameter on boot.
There is no support for more fine grained debug control like
possible with slub_debug=xxx. [31mCONFIG_SLUB[0m debugging may be switched
off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
"slub_debug=-".
config [31mCONFIG_SLUB_STATS[0m
default n
bool "Enable SLUB performance statistics"
depends on [31mCONFIG_SLUB[0m && [31mCONFIG_SYSFS[0m
help
[31mCONFIG_SLUB[0m 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 [31mCONFIG_HAVE_DEBUG_KMEMLEAK[0m
bool
config [31mCONFIG_DEBUG_KMEMLEAK[0m
bool "Kernel memory leak detector"
depends on [31mCONFIG_DEBUG_KERNEL[0m && [31mCONFIG_HAVE_DEBUG_KMEMLEAK[0m
select [31mCONFIG_DEBUG_FS[0m
select [31mCONFIG_STACKTRACE[0m if [31mCONFIG_STACKTRACE_SUPPORT[0m
select [31mCONFIG_KALLSYMS[0m
select [31mCONFIG_CRC32[0m
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 [31mCONFIG_DEBUG_SLAB[0m or [31mCONFIG_SLUB_DEBUG[0m 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 [31mCONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE[0m
int "Kmemleak memory pool size"
depends on [31mCONFIG_DEBUG_KMEMLEAK[0m
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 [31mCONFIG_DEBUG_KMEMLEAK_TEST[0m
tristate "Simple test for the kernel memory leak detector"
depends on [31mCONFIG_DEBUG_KMEMLEAK[0m && m
help
This option enables a module that explicitly leaks memory.
If unsure, say N.
config [31mCONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF[0m
bool "Default kmemleak to off"
depends on [31mCONFIG_DEBUG_KMEMLEAK[0m
help
Say Y here to disable kmemleak by default. It can then be enabled
on the command line via kmemleak=on.
config [31mCONFIG_DEBUG_KMEMLEAK_AUTO_SCAN[0m
bool "Enable kmemleak auto scan thread on boot up"
default y
depends on [31mCONFIG_DEBUG_KMEMLEAK[0m
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 [31mCONFIG_DEBUG_STACK_USAGE[0m
bool "Stack utilization instrumentation"
depends on [31mCONFIG_DEBUG_KERNEL[0m && ![31mCONFIG_IA64[0m
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 [31mCONFIG_DEBUG_VM[0m
bool "Debug VM"
depends on [31mCONFIG_DEBUG_KERNEL[0m
help
Enable this to turn on extended checks in the virtual-memory system
that may impact performance.
If unsure, say N.
config [31mCONFIG_DEBUG_VM_VMACACHE[0m
bool "Debug VMA caching"
depends on [31mCONFIG_DEBUG_VM[0m
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 [31mCONFIG_DEBUG_VM_RB[0m
bool "Debug VM red-black trees"
depends on [31mCONFIG_DEBUG_VM[0m
help
Enable VM red-black tree debugging information and extra validations.
If unsure, say N.
config [31mCONFIG_DEBUG_VM_PGFLAGS[0m
bool "Debug page-flags operations"
depends on [31mCONFIG_DEBUG_VM[0m
help
Enables extra validation on page flags operations.
If unsure, say N.
config [31mCONFIG_ARCH_HAS_DEBUG_VIRTUAL[0m
bool
config [31mCONFIG_DEBUG_VIRTUAL[0m
bool "Debug VM translations"
depends on [31mCONFIG_DEBUG_KERNEL[0m && [31mCONFIG_ARCH_HAS_DEBUG_VIRTUAL[0m
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 [31mCONFIG_DEBUG_NOMMU_REGIONS[0m
bool "Debug the global anon/private NOMMU mapping region tree"
depends on [31mCONFIG_DEBUG_KERNEL[0m && ![31mCONFIG_MMU[0m
help
This option causes the global tree of anonymous and private mapping
regions to be regularly checked for invalid topology.
config [31mCONFIG_DEBUG_MEMORY_INIT[0m
bool "Debug memory initialisation" if [31mCONFIG_EXPERT[0m
default ![31mCONFIG_EXPERT[0m
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 [31mCONFIG_MEMORY_NOTIFIER_ERROR_INJECT[0m
tristate "Memory hotplug notifier error injection module"
depends on [31mCONFIG_MEMORY_HOTPLUG_SPARSE[0m && [31mCONFIG_NOTIFIER_ERROR_INJECTION[0m
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 [31mCONFIG_M[0m here: the module will
be called memory-notifier-error-inject.
If unsure, say N.
config [31mCONFIG_DEBUG_PER_CPU_MAPS[0m
bool "Debug access to per_cpu maps"
depends on [31mCONFIG_DEBUG_KERNEL[0m
depends on [31mCONFIG_SMP[0m
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 [31mCONFIG_DEBUG_HIGHMEM[0m
bool "Highmem debugging"
depends on [31mCONFIG_DEBUG_KERNEL[0m && [31mCONFIG_HIGHMEM[0m
help
This option enables additional error checking for high memory
systems. Disable for production systems.
config [31mCONFIG_HAVE_DEBUG_STACKOVERFLOW[0m
bool
config [31mCONFIG_DEBUG_STACKOVERFLOW[0m
bool "Check for stack overflows"
depends on [31mCONFIG_DEBUG_KERNEL[0m && [31mCONFIG_HAVE_DEBUG_STACKOVERFLOW[0m
---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"
endmenu # "Memory Debugging"
config [31mCONFIG_ARCH_HAS_KCOV[0m
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 [31mCONFIG_CC_HAS_SANCOV_TRACE_PC[0m
def_bool $(cc-option,-fsanitize-coverage=trace-pc)
config [31mCONFIG_KCOV[0m
bool "Code coverage for fuzzing"
depends on [31mCONFIG_ARCH_HAS_KCOV[0m
depends on [31mCONFIG_CC_HAS_SANCOV_TRACE_PC[0m || [31mCONFIG_GCC_PLUGINS[0m
select [31mCONFIG_DEBUG_FS[0m
select [31mCONFIG_GCC_PLUGIN_SANCOV[0m if ![31mCONFIG_CC_HAS_SANCOV_TRACE_PC[0m
help
[31mCONFIG_KCOV[0m exposes kernel code coverage information in a form suitable
for coverage-guided fuzzing (randomized testing).
If [31mCONFIG_RANDOMIZE_BASE[0m is enabled, PC values will not be stable across
different machines and across reboots. If you need stable PC values,
disable [31mCONFIG_RANDOMIZE_BASE[0m.
For more details, see Documentation/dev-tools/kcov.rst.
config [31mCONFIG_KCOV_ENABLE_COMPARISONS[0m
bool "Enable comparison operands collection by KCOV"
depends on [31mCONFIG_KCOV[0m
depends on $(cc-option,-fsanitize-coverage=trace-cmp)
help
[31mCONFIG_KCOV[0m 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 [31mCONFIG_KCOV_INSTRUMENT_ALL[0m
bool "Instrument all code by default"
depends on [31mCONFIG_KCOV[0m
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 [31mCONFIG_DEBUG_SHIRQ[0m
bool "Debug shared IRQ handlers"
depends on [31mCONFIG_DEBUG_KERNEL[0m
help
Enable this to generate a spurious interrupt as soon as a shared
interrupt handler is registered, and just before one is deregistered.
Drivers ought to be able to handle interrupts coming in at those
points; some don't and need to be caught.
menu "Debug Lockups and Hangs"
config [31mCONFIG_LOCKUP_DETECTOR[0m
bool
config [31mCONFIG_SOFTLOCKUP_DETECTOR[0m
bool "Detect Soft Lockups"
depends on [31mCONFIG_DEBUG_KERNEL[0m && ![31mCONFIG_S390[0m
select [31mCONFIG_LOCKUP_DETECTOR[0m
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 [31mCONFIG_BOOTPARAM_SOFTLOCKUP_PANIC[0m
bool "Panic (Reboot) On Soft Lockups"
depends on [31mCONFIG_SOFTLOCKUP_DETECTOR[0m
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 [31mCONFIG_BOOTPARAM_SOFTLOCKUP_PANIC_VALUE[0m
int
depends on [31mCONFIG_SOFTLOCKUP_DETECTOR[0m
range 0 1
default 0 if ![31mCONFIG_BOOTPARAM_SOFTLOCKUP_PANIC[0m
default 1 if [31mCONFIG_BOOTPARAM_SOFTLOCKUP_PANIC[0m
config [31mCONFIG_HARDLOCKUP_DETECTOR_PERF[0m
bool
select [31mCONFIG_SOFTLOCKUP_DETECTOR[0m
#
# Enables a timestamp based low pass filter to compensate for perf based
# hard lockup detection which runs too fast due to turbo modes.
#
config [31mCONFIG_HARDLOCKUP_CHECK_TIMESTAMP[0m
bool
#
# arch/ can define [31mCONFIG_HAVE_HARDLOCKUP_DETECTOR_ARCH[0m to provide their own hard
# lockup detector rather than the perf based detector.
#
config [31mCONFIG_HARDLOCKUP_DETECTOR[0m
bool "Detect Hard Lockups"
depends on [31mCONFIG_DEBUG_KERNEL[0m && ![31mCONFIG_S390[0m
depends on [31mCONFIG_HAVE_HARDLOCKUP_DETECTOR_PERF[0m || [31mCONFIG_HAVE_HARDLOCKUP_DETECTOR_ARCH[0m
select [31mCONFIG_LOCKUP_DETECTOR[0m
select [31mCONFIG_HARDLOCKUP_DETECTOR_PERF[0m if [31mCONFIG_HAVE_HARDLOCKUP_DETECTOR_PERF[0m
select HARDLOCKUP_DETECTOR_ARCH if [31mCONFIG_HAVE_HARDLOCKUP_DETECTOR_ARCH[0m
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 [31mCONFIG_BOOTPARAM_HARDLOCKUP_PANIC[0m
bool "Panic (Reboot) On Hard Lockups"
depends on [31mCONFIG_HARDLOCKUP_DETECTOR[0m
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 [31mCONFIG_BOOTPARAM_HARDLOCKUP_PANIC_VALUE[0m
int
depends on [31mCONFIG_HARDLOCKUP_DETECTOR[0m
range 0 1
default 0 if ![31mCONFIG_BOOTPARAM_HARDLOCKUP_PANIC[0m
default 1 if [31mCONFIG_BOOTPARAM_HARDLOCKUP_PANIC[0m
config [31mCONFIG_DETECT_HUNG_TASK[0m
bool "Detect Hung Tasks"
depends on [31mCONFIG_DEBUG_KERNEL[0m
default [31mCONFIG_SOFTLOCKUP_DETECTOR[0m
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 [31mCONFIG_DEFAULT_HUNG_TASK_TIMEOUT[0m
int "Default timeout for hung task detection (in seconds)"
depends on [31mCONFIG_DETECT_HUNG_TASK[0m
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.
[31mCONFIG_A[0m timeout of 0 disables the check. The default is two minutes.
Keeping the default should be fine in most cases.
config [31mCONFIG_BOOTPARAM_HUNG_TASK_PANIC[0m
bool "Panic (Reboot) On Hung Tasks"
depends on [31mCONFIG_DETECT_HUNG_TASK[0m
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 [31mCONFIG_BOOTPARAM_HUNG_TASK_PANIC_VALUE[0m
int
depends on [31mCONFIG_DETECT_HUNG_TASK[0m
range 0 1
default 0 if ![31mCONFIG_BOOTPARAM_HUNG_TASK_PANIC[0m
default 1 if [31mCONFIG_BOOTPARAM_HUNG_TASK_PANIC[0m
config [31mCONFIG_WQ_WATCHDOG[0m
bool "Detect Workqueue Stalls"
depends on [31mCONFIG_DEBUG_KERNEL[0m
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.
endmenu # "Debug lockups and hangs"
config [31mCONFIG_PANIC_ON_OOPS[0m
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 [31mCONFIG_PANIC_ON_OOPS_VALUE[0m
int
range 0 1
default 0 if ![31mCONFIG_PANIC_ON_OOPS[0m
default 1 if [31mCONFIG_PANIC_ON_OOPS[0m
config [31mCONFIG_PANIC_TIMEOUT[0m
int "panic timeout"
default 0
help
Set the timeout value (in seconds) until a reboot occurs when the
the kernel panics. If n = 0, then we wait forever. [31mCONFIG_A[0m timeout
value n > 0 will wait n seconds before rebooting, while a timeout
value n < 0 will reboot immediately.
config [31mCONFIG_SCHED_DEBUG[0m
bool "Collect scheduler debugging info"
depends on [31mCONFIG_DEBUG_KERNEL[0m && [31mCONFIG_PROC_FS[0m
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 [31mCONFIG_SCHED_INFO[0m
bool
default n
config [31mCONFIG_SCHEDSTATS[0m
bool "Collect scheduler statistics"
depends on [31mCONFIG_DEBUG_KERNEL[0m && [31mCONFIG_PROC_FS[0m
select [31mCONFIG_SCHED_INFO[0m
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.
config [31mCONFIG_SCHED_STACK_END_CHECK[0m
bool "Detect stack corruption on calls to schedule()"
depends on [31mCONFIG_DEBUG_KERNEL[0m
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 [31mCONFIG_DEBUG_TIMEKEEPING[0m
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 [31mCONFIG_DEBUG_PREEMPT[0m
bool "Debug preemptible kernel"
depends on [31mCONFIG_DEBUG_KERNEL[0m && [31mCONFIG_PREEMPT[0m && [31mCONFIG_TRACE_IRQFLAGS_SUPPORT[0m
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 [31mCONFIG_LOCK_DEBUGGING_SUPPORT[0m
bool
depends on [31mCONFIG_TRACE_IRQFLAGS_SUPPORT[0m && [31mCONFIG_STACKTRACE_SUPPORT[0m && [31mCONFIG_LOCKDEP_SUPPORT[0m
default y
config [31mCONFIG_PROVE_LOCKING[0m
bool "Lock debugging: prove locking correctness"
depends on [31mCONFIG_DEBUG_KERNEL[0m && [31mCONFIG_LOCK_DEBUGGING_SUPPORT[0m
select [31mCONFIG_LOCKDEP[0m
select [31mCONFIG_DEBUG_SPINLOCK[0m
select [31mCONFIG_DEBUG_MUTEXES[0m
select [31mCONFIG_DEBUG_RT_MUTEXES[0m if [31mCONFIG_RT_MUTEXES[0m
select [31mCONFIG_DEBUG_RWSEMS[0m
select [31mCONFIG_DEBUG_WW_MUTEX_SLOWPATH[0m
select [31mCONFIG_DEBUG_LOCK_ALLOC[0m
select [31mCONFIG_TRACE_IRQFLAGS[0m
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 [31mCONFIG_LOCK_STAT[0m
bool "Lock usage statistics"
depends on [31mCONFIG_DEBUG_KERNEL[0m && [31mCONFIG_LOCK_DEBUGGING_SUPPORT[0m
select [31mCONFIG_LOCKDEP[0m
select [31mCONFIG_DEBUG_SPINLOCK[0m
select [31mCONFIG_DEBUG_MUTEXES[0m
select [31mCONFIG_DEBUG_RT_MUTEXES[0m if [31mCONFIG_RT_MUTEXES[0m
select [31mCONFIG_DEBUG_LOCK_ALLOC[0m
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 [31mCONFIG_DEBUG_RT_MUTEXES[0m
bool "RT Mutex debugging, deadlock detection"
depends on [31mCONFIG_DEBUG_KERNEL[0m && [31mCONFIG_RT_MUTEXES[0m
help
This allows rt mutex semantics violations and rt mutex related
deadlocks (lockups) to be detected and reported automatically.
config [31mCONFIG_DEBUG_SPINLOCK[0m
bool "Spinlock and rw-lock debugging: basic checks"
depends on [31mCONFIG_DEBUG_KERNEL[0m
select [31mCONFIG_UNINLINE_SPIN_UNLOCK[0m
help
Say Y here and build [31mCONFIG_SMP[0m 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 [31mCONFIG_DEBUG_MUTEXES[0m
bool "Mutex debugging: basic checks"
depends on [31mCONFIG_DEBUG_KERNEL[0m
help
This feature allows mutex semantics violations to be detected and
reported.
config [31mCONFIG_DEBUG_WW_MUTEX_SLOWPATH[0m
bool "Wait/wound mutex debugging: Slowpath testing"
depends on [31mCONFIG_DEBUG_KERNEL[0m && [31mCONFIG_LOCK_DEBUGGING_SUPPORT[0m
select [31mCONFIG_DEBUG_LOCK_ALLOC[0m
select [31mCONFIG_DEBUG_SPINLOCK[0m
select [31mCONFIG_DEBUG_MUTEXES[0m
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 [31mCONFIG_DEBUG_RWSEMS[0m
bool "RW Semaphore debugging: basic checks"
depends on [31mCONFIG_DEBUG_KERNEL[0m
help
This debugging feature allows mismatched rw semaphore locks
and unlocks to be detected and reported.
config [31mCONFIG_DEBUG_LOCK_ALLOC[0m
bool "Lock debugging: detect incorrect freeing of live locks"
depends on [31mCONFIG_DEBUG_KERNEL[0m && [31mCONFIG_LOCK_DEBUGGING_SUPPORT[0m
select [31mCONFIG_DEBUG_SPINLOCK[0m
select [31mCONFIG_DEBUG_MUTEXES[0m
select [31mCONFIG_DEBUG_RT_MUTEXES[0m if [31mCONFIG_RT_MUTEXES[0m
select [31mCONFIG_LOCKDEP[0m
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 [31mCONFIG_LOCKDEP[0m
bool
depends on [31mCONFIG_DEBUG_KERNEL[0m && [31mCONFIG_LOCK_DEBUGGING_SUPPORT[0m
select [31mCONFIG_STACKTRACE[0m
select [31mCONFIG_FRAME_POINTER[0m if ![31mCONFIG_MIPS[0m && ![31mCONFIG_PPC[0m && ![31mCONFIG_ARM[0m && ![31mCONFIG_S390[0m && ![31mCONFIG_MICROBLAZE[0m && ![31mCONFIG_ARC[0m && ![31mCONFIG_X86[0m
select [31mCONFIG_KALLSYMS[0m
select [31mCONFIG_KALLSYMS_ALL[0m
config [31mCONFIG_LOCKDEP_SMALL[0m
bool
config [31mCONFIG_DEBUG_LOCKDEP[0m
bool "Lock dependency engine debugging"
depends on [31mCONFIG_DEBUG_KERNEL[0m && [31mCONFIG_LOCKDEP[0m
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 [31mCONFIG_DEBUG_ATOMIC_SLEEP[0m
bool "Sleep inside atomic section checking"
select [31mCONFIG_PREEMPT_COUNT[0m
depends on [31mCONFIG_DEBUG_KERNEL[0m
depends on ![31mCONFIG_ARCH_NO_PREEMPT[0m
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 [31mCONFIG_DEBUG_LOCKING_API_SELFTESTS[0m
bool "Locking API boot-time self-tests"
depends on [31mCONFIG_DEBUG_KERNEL[0m
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 [31mCONFIG_LOCK_TORTURE_TEST[0m
tristate "torture tests for locking"
depends on [31mCONFIG_DEBUG_KERNEL[0m
select [31mCONFIG_TORTURE_TEST[0m
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 [31mCONFIG_M[0m if you want these torture tests to build as a module.
Say N if you are unsure.
config [31mCONFIG_WW_MUTEX_SELFTEST[0m
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 [31mCONFIG_DEBUG_WW_MUTEX_SLOWPATH[0m in conjunction
with this test harness.
Say [31mCONFIG_M[0m if you want these self tests to build as a module.
Say N if you are unsure.
endmenu # lock debugging
config [31mCONFIG_TRACE_IRQFLAGS[0m
bool
help
Enables hooks to interrupt enabling and disabling for
either tracing or lock debugging.
config [31mCONFIG_STACKTRACE[0m
bool "Stack backtrace support"
depends on [31mCONFIG_STACKTRACE_SUPPORT[0m
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 [31mCONFIG_WARN_ALL_UNSEEDED_RANDOM[0m
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 the kernel will issue only a single
warning for the first use of unseeded randomness.
Say Y here if you want to receive warnings for all uses of
unseeded randomness. This will be of use primarily for
those developers interested in improving the security of
Linux kernels running on their architecture (or
subarchitecture).
config [31mCONFIG_DEBUG_KOBJECT[0m
bool "kobject debugging"
depends on [31mCONFIG_DEBUG_KERNEL[0m
help
If you say Y here, some extra kobject debugging messages will be sent
to the syslog.
config [31mCONFIG_DEBUG_KOBJECT_RELEASE[0m
bool "kobject release debugging"
depends on [31mCONFIG_DEBUG_OBJECTS_TIMERS[0m
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 [31mCONFIG_HAVE_DEBUG_BUGVERBOSE[0m
bool
config [31mCONFIG_DEBUG_BUGVERBOSE[0m
bool "Verbose BUG() reporting (adds 70K)" if [31mCONFIG_DEBUG_KERNEL[0m && [31mCONFIG_EXPERT[0m
depends on [31mCONFIG_BUG[0m && ([31mCONFIG_GENERIC_BUG[0m || [31mCONFIG_HAVE_DEBUG_BUGVERBOSE[0m)
default y
help
Say Y here to make [31mCONFIG_BUG[0m() panics output the file name and line number
of the [31mCONFIG_BUG[0m call as well as the EIP and oops trace. This aids
debugging but costs about 70-100K of memory.
config [31mCONFIG_DEBUG_LIST[0m
bool "Debug linked list manipulation"
depends on [31mCONFIG_DEBUG_KERNEL[0m || [31mCONFIG_BUG_ON_DATA_CORRUPTION[0m
help
Enable this to turn on extended checks in the linked-list
walking routines.
If unsure, say N.
config [31mCONFIG_DEBUG_PLIST[0m
bool "Debug priority linked list manipulation"
depends on [31mCONFIG_DEBUG_KERNEL[0m
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 [31mCONFIG_DEBUG_SG[0m
bool "Debug SG table operations"
depends on [31mCONFIG_DEBUG_KERNEL[0m
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 [31mCONFIG_DEBUG_NOTIFIERS[0m
bool "Debug notifier call chains"
depends on [31mCONFIG_DEBUG_KERNEL[0m
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 [31mCONFIG_DEBUG_CREDENTIALS[0m
bool "Debug credential management"
depends on [31mCONFIG_DEBUG_KERNEL[0m
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 [31mCONFIG_DEBUG_WQ_FORCE_RR_CPU[0m
bool "Force round-robin CPU selection for unbound work items"
depends on [31mCONFIG_DEBUG_KERNEL[0m
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 [31mCONFIG_DEBUG_BLOCK_EXT_DEVT[0m
bool "Force extended block device numbers and spread them"
depends on [31mCONFIG_DEBUG_KERNEL[0m
depends on [31mCONFIG_BLOCK[0m
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 [31mCONFIG_IDE[0m and [31mCONFIG_SCSI[0m 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 [31mCONFIG_CPU_HOTPLUG_STATE_CONTROL[0m
bool "Enable CPU hotplug state control"
depends on [31mCONFIG_DEBUG_KERNEL[0m
depends on [31mCONFIG_HOTPLUG_CPU[0m
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 [31mCONFIG_NOTIFIER_ERROR_INJECTION[0m
tristate "Notifier error injection"
depends on [31mCONFIG_DEBUG_KERNEL[0m
select [31mCONFIG_DEBUG_FS[0m
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 [31mCONFIG_PM_NOTIFIER_ERROR_INJECT[0m
tristate "PM notifier error injection module"
depends on [31mCONFIG_PM[0m && [31mCONFIG_NOTIFIER_ERROR_INJECTION[0m
default m if [31mCONFIG_PM_DEBUG[0m
help
This option provides the ability to inject artificial errors to
[31mCONFIG_PM[0m 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 [31mCONFIG_PM[0m 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 [31mCONFIG_M[0m here: the module will
be called pm-notifier-error-inject.
If unsure, say N.
config [31mCONFIG_OF_RECONFIG_NOTIFIER_ERROR_INJECT[0m
tristate "OF reconfig notifier error injection module"
depends on [31mCONFIG_OF_DYNAMIC[0m && [31mCONFIG_NOTIFIER_ERROR_INJECTION[0m
help
This option provides the ability to inject artificial errors to
[31mCONFIG_OF[0m reconfig notifier chain callbacks. It is controlled
through debugfs interface under
/sys/kernel/debug/notifier-error-inject/[31mCONFIG_OF[0m-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 [31mCONFIG_M[0m here: the module will
be called of-reconfig-notifier-error-inject.
If unsure, say N.
config [31mCONFIG_NETDEV_NOTIFIER_ERROR_INJECT[0m
tristate "Netdev notifier error injection module"
depends on [31mCONFIG_NET[0m && [31mCONFIG_NOTIFIER_ERROR_INJECTION[0m
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 [31mCONFIG_M[0m here: the module will
be called netdev-notifier-error-inject.
If unsure, say N.
config [31mCONFIG_FUNCTION_ERROR_INJECTION[0m
def_bool y
depends on [31mCONFIG_HAVE_FUNCTION_ERROR_INJECTION[0m && [31mCONFIG_KPROBES[0m
config [31mCONFIG_FAULT_INJECTION[0m
bool "Fault-injection framework"
depends on [31mCONFIG_DEBUG_KERNEL[0m
help
Provide fault-injection framework.
For more details, see Documentation/fault-injection/.
config [31mCONFIG_FAILSLAB[0m
bool "Fault-injection capability for kmalloc"
depends on [31mCONFIG_FAULT_INJECTION[0m
depends on [31mCONFIG_SLAB[0m || [31mCONFIG_SLUB[0m
help
Provide fault-injection capability for kmalloc.
config [31mCONFIG_FAIL_PAGE_ALLOC[0m
bool "Fault-injection capabilitiy for alloc_pages()"
depends on [31mCONFIG_FAULT_INJECTION[0m
help
Provide fault-injection capability for alloc_pages().
config [31mCONFIG_FAIL_MAKE_REQUEST[0m
bool "Fault-injection capability for disk IO"
depends on [31mCONFIG_FAULT_INJECTION[0m && [31mCONFIG_BLOCK[0m
help
Provide fault-injection capability for disk IO.
config [31mCONFIG_FAIL_IO_TIMEOUT[0m
bool "Fault-injection capability for faking disk interrupts"
depends on [31mCONFIG_FAULT_INJECTION[0m && [31mCONFIG_BLOCK[0m
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 [31mCONFIG_FAIL_FUTEX[0m
bool "Fault-injection capability for futexes"
select [31mCONFIG_DEBUG_FS[0m
depends on [31mCONFIG_FAULT_INJECTION[0m && [31mCONFIG_FUTEX[0m
help
Provide fault-injection capability for futexes.
config [31mCONFIG_FAULT_INJECTION_DEBUG_FS[0m
bool "Debugfs entries for fault-injection capabilities"
depends on [31mCONFIG_FAULT_INJECTION[0m && [31mCONFIG_SYSFS[0m && [31mCONFIG_DEBUG_FS[0m
help
Enable configuration of fault-injection capabilities via debugfs.
config [31mCONFIG_FAIL_FUNCTION[0m
bool "Fault-injection capability for functions"
depends on [31mCONFIG_FAULT_INJECTION_DEBUG_FS[0m && [31mCONFIG_FUNCTION_ERROR_INJECTION[0m
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 [31mCONFIG_FAIL_MMC_REQUEST[0m
bool "Fault-injection capability for MMC IO"
depends on [31mCONFIG_FAULT_INJECTION_DEBUG_FS[0m && [31mCONFIG_MMC[0m
help
Provide fault-injection capability for [31mCONFIG_MMC[0m 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 [31mCONFIG_FAULT_INJECTION_STACKTRACE_FILTER[0m
bool "stacktrace filter for fault-injection capabilities"
depends on [31mCONFIG_FAULT_INJECTION_DEBUG_FS[0m && [31mCONFIG_STACKTRACE_SUPPORT[0m
depends on ![31mCONFIG_X86_64[0m
select [31mCONFIG_STACKTRACE[0m
select [31mCONFIG_FRAME_POINTER[0m if ![31mCONFIG_MIPS[0m && ![31mCONFIG_PPC[0m && ![31mCONFIG_S390[0m && ![31mCONFIG_MICROBLAZE[0m && ![31mCONFIG_ARM[0m && ![31mCONFIG_ARC[0m && ![31mCONFIG_X86[0m
help
Provide stacktrace filter for fault-injection capabilities
config [31mCONFIG_LATENCYTOP[0m
bool "Latency measuring infrastructure"
depends on [31mCONFIG_DEBUG_KERNEL[0m
depends on [31mCONFIG_STACKTRACE_SUPPORT[0m
depends on [31mCONFIG_PROC_FS[0m
select [31mCONFIG_FRAME_POINTER[0m if ![31mCONFIG_MIPS[0m && ![31mCONFIG_PPC[0m && ![31mCONFIG_S390[0m && ![31mCONFIG_MICROBLAZE[0m && ![31mCONFIG_ARM[0m && ![31mCONFIG_ARC[0m && ![31mCONFIG_X86[0m
select [31mCONFIG_KALLSYMS[0m
select [31mCONFIG_KALLSYMS_ALL[0m
select [31mCONFIG_STACKTRACE[0m
select [31mCONFIG_SCHEDSTATS[0m
select [31mCONFIG_SCHED_DEBUG[0m
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 [31mCONFIG_PROVIDE_OHCI1394_DMA_INIT[0m
bool "Remote debugging over FireWire early on boot"
depends on [31mCONFIG_PCI[0m && [31mCONFIG_X86[0m
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 [31mCONFIG_PCI[0m config space.
As all changes to the FireWire bus such as enabling and disabling
devices cause a bus reset and thereby disable remote DMA for all
devices, be sure to have the cable plugged and FireWire enabled on
the debugging host before booting the debug target for debugging.
This code (~1k) is freed after boot. By then, the firewire stack
in charge of the OHCI-1394 controllers should be used instead.
See Documentation/debugging-via-ohci1394.txt for more information.
menuconfig [31mCONFIG_RUNTIME_TESTING_MENU[0m
bool "Runtime Testing"
def_bool y
if [31mCONFIG_RUNTIME_TESTING_MENU[0m
config [31mCONFIG_LKDTM[0m
tristate "Linux Kernel Dump Test Tool Module"
depends on [31mCONFIG_DEBUG_FS[0m
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 [31mCONFIG_M[0m 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 [31mCONFIG_TEST_LIST_SORT[0m
tristate "Linked list sorting test"
depends on [31mCONFIG_DEBUG_KERNEL[0m || 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 [31mCONFIG_TEST_SORT[0m
tristate "Array-based sort test"
depends on [31mCONFIG_DEBUG_KERNEL[0m || m
help
This option enables the self-test function of 'sort()' at boot,
or at module load time.
If unsure, say N.
config [31mCONFIG_KPROBES_SANITY_TEST[0m
bool "Kprobes sanity tests"
depends on [31mCONFIG_DEBUG_KERNEL[0m
depends on [31mCONFIG_KPROBES[0m
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 [31mCONFIG_BACKTRACE_SELF_TEST[0m
tristate "Self test for the backtrace code"
depends on [31mCONFIG_DEBUG_KERNEL[0m
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 [31mCONFIG_STACKTRACE[0m as well.
Say N if you are unsure.
config [31mCONFIG_RBTREE_TEST[0m
tristate "Red-Black tree test"
depends on [31mCONFIG_DEBUG_KERNEL[0m
help
[31mCONFIG_A[0m benchmark measuring the performance of the rbtree library.
Also includes rbtree invariant checks.
config [31mCONFIG_REED_SOLOMON_TEST[0m
tristate "Reed-Solomon library test"
depends on [31mCONFIG_DEBUG_KERNEL[0m || m
select [31mCONFIG_REED_SOLOMON[0m
select [31mCONFIG_REED_SOLOMON_ENC16[0m
select [31mCONFIG_REED_SOLOMON_DEC16[0m
help
This option enables the self-test function of rslib at boot,
or at module load time.
If unsure, say N.
config [31mCONFIG_INTERVAL_TREE_TEST[0m
tristate "Interval tree test"
depends on [31mCONFIG_DEBUG_KERNEL[0m
select [31mCONFIG_INTERVAL_TREE[0m
help
[31mCONFIG_A[0m benchmark measuring the performance of the interval tree library
config [31mCONFIG_PERCPU_TEST[0m
tristate "Per cpu operations test"
depends on m && [31mCONFIG_DEBUG_KERNEL[0m
help
Enable this option to build test module which validates per-cpu
operations.
If unsure, say N.
config [31mCONFIG_ATOMIC64_SELFTEST[0m
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 [31mCONFIG_ASYNC_RAID6_TEST[0m
tristate "Self test for hardware accelerated raid6 recovery"
depends on [31mCONFIG_ASYNC_RAID6_RECOV[0m
select [31mCONFIG_ASYNC_MEMCPY[0m
---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 [31mCONFIG_TEST_HEXDUMP[0m
tristate "Test functions located in the hexdump module at runtime"
config [31mCONFIG_TEST_STRING_HELPERS[0m
tristate "Test functions located in the string_helpers module at runtime"
config [31mCONFIG_TEST_STRSCPY[0m
tristate "Test strscpy*() family of functions at runtime"
config [31mCONFIG_TEST_KSTRTOX[0m
tristate "Test kstrto*() family of functions at runtime"
config [31mCONFIG_TEST_PRINTF[0m
tristate "Test printf() family of functions at runtime"
config [31mCONFIG_TEST_BITMAP[0m
tristate "Test bitmap_*() family of functions at runtime"
help
Enable this option to test the bitmap functions at boot.
If unsure, say N.
config [31mCONFIG_TEST_BITFIELD[0m
tristate "Test bitfield functions at runtime"
help
Enable this option to test the bitfield functions at boot.
If unsure, say N.
config [31mCONFIG_TEST_UUID[0m
tristate "Test functions located in the uuid module at runtime"
config [31mCONFIG_TEST_XARRAY[0m
tristate "Test the XArray code at runtime"
config [31mCONFIG_TEST_OVERFLOW[0m
tristate "Test check_*_overflow() functions at runtime"
config [31mCONFIG_TEST_RHASHTABLE[0m
tristate "Perform selftest on resizable hash table"
help
Enable this option to test the rhashtable functions at boot.
If unsure, say N.
config [31mCONFIG_TEST_HASH[0m
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 [31mCONFIG_TEST_IDA[0m
tristate "Perform selftest on IDA functions"
config [31mCONFIG_TEST_PARMAN[0m
tristate "Perform selftest on priority array manager"
depends on [31mCONFIG_PARMAN[0m
help
Enable this option to test priority array manager on boot
(or module load).
If unsure, say N.
config [31mCONFIG_TEST_IRQ_TIMINGS[0m
bool "IRQ timings selftest"
depends on [31mCONFIG_IRQ_TIMINGS[0m
help
Enable this option to test the irq timings code on boot.
If unsure, say N.
config [31mCONFIG_TEST_LKM[0m
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 [31mCONFIG_TEST_VMALLOC[0m
tristate "Test module for stress/performance analysis of vmalloc allocator"
default n
depends on [31mCONFIG_MMU[0m
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 [31mCONFIG_TEST_USER_COPY[0m
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 [31mCONFIG_TEST_BPF[0m
tristate "Test BPF filter functionality"
depends on m && [31mCONFIG_NET[0m
help
This builds the "test_bpf" module that runs various test vectors
against the [31mCONFIG_BPF[0m interpreter or [31mCONFIG_BPF[0m JIT compiler depending on the
current setting. This is in particular useful for [31mCONFIG_BPF[0m 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 [31mCONFIG_TEST_BLACKHOLE_DEV[0m
tristate "Test blackhole netdev functionality"
depends on m && [31mCONFIG_NET[0m
help
This builds the "test_blackhole_dev" module that validates the
data path through this blackhole netdev.
If unsure, say N.
config [31mCONFIG_FIND_BIT_BENCHMARK[0m
tristate "Test find_bit functions"
help
This builds the "test_find_bit" module that measure find_*_bit()
functions performance.
If unsure, say N.
config [31mCONFIG_TEST_FIRMWARE[0m
tristate "Test firmware loading via userspace interface"
depends on [31mCONFIG_FW_LOADER[0m
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 [31mCONFIG_TEST_SYSCTL[0m
tristate "sysctl test driver"
depends on [31mCONFIG_PROC_SYSCTL[0m
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 [31mCONFIG_TEST_UDELAY[0m
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 [31mCONFIG_TEST_STATIC_KEYS[0m
tristate "Test static keys"
depends on m
help
Test the static key interfaces.
If unsure, say N.
config [31mCONFIG_TEST_KMOD[0m
tristate "kmod stress tester"
depends on m
depends on [31mCONFIG_NETDEVICES[0m && [31mCONFIG_NET_CORE[0m && [31mCONFIG_INET[0m # for [31mCONFIG_TUN[0m
depends on [31mCONFIG_BLOCK[0m
select [31mCONFIG_TEST_LKM[0m
select [31mCONFIG_XFS_FS[0m
select [31mCONFIG_TUN[0m
select [31mCONFIG_BTRFS_FS[0m
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 [31mCONFIG_TEST_DEBUG_VIRTUAL[0m
tristate "Test CONFIG_DEBUG_VIRTUAL feature"
depends on [31mCONFIG_DEBUG_VIRTUAL[0m
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 [31mCONFIG_TEST_MEMCAT_P[0m
tristate "Test memcat_p() helper function"
help
Test the memcat_p() helper for correctly merging two
pointer arrays together.
If unsure, say N.
config [31mCONFIG_TEST_LIVEPATCH[0m
tristate "Test livepatching"
default n
depends on [31mCONFIG_DYNAMIC_DEBUG[0m
depends on [31mCONFIG_LIVEPATCH[0m
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 -[31mCONFIG_C[0m 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 [31mCONFIG_TEST_OBJAGG[0m
tristate "Perform selftest on object aggreration manager"
default n
depends on [31mCONFIG_OBJAGG[0m
help
Enable this option to test object aggregation manager on boot
(or module load).
config [31mCONFIG_TEST_STACKINIT[0m
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 [31mCONFIG_TEST_MEMINIT[0m
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.
endif # [31mCONFIG_RUNTIME_TESTING_MENU[0m
config [31mCONFIG_MEMTEST[0m
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 [31mCONFIG_BUG_ON_DATA_CORRUPTION[0m
bool "Trigger a BUG when data corruption is detected"
select [31mCONFIG_DEBUG_LIST[0m
help
Select this option if the kernel should [31mCONFIG_BUG[0m when it encounters
data corruption in kernel memory structures when they get checked
for validity.
If unsure, say N.
source "samples/Kconfig"
source "lib/Kconfig.kgdb"
source "lib/Kconfig.ubsan"
config [31mCONFIG_ARCH_HAS_DEVMEM_IS_ALLOWED[0m
bool
config [31mCONFIG_STRICT_DEVMEM[0m
bool "Filter access to /dev/mem"
depends on [31mCONFIG_MMU[0m && [31mCONFIG_DEVMEM[0m
depends on [31mCONFIG_ARCH_HAS_DEVMEM_IS_ALLOWED[0m
default y if [31mCONFIG_PPC[0m || [31mCONFIG_X86[0m || [31mCONFIG_ARM64[0m
---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 [31mCONFIG_IO_STRICT_DEVMEM[0m=n, the /dev/mem
file only allows userspace access to [31mCONFIG_PCI[0m 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 [31mCONFIG_IO_STRICT_DEVMEM[0m
bool "Filter I/O access to /dev/mem"
depends on [31mCONFIG_STRICT_DEVMEM[0m
---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.
source "arch/$(SRCARCH)/Kconfig.debug"
endmenu # Kernel hacking