kdump-config { help | test | show | status | load | unload | savecore }


kdump-config manages the kdump feature of the Linux kernel. When a kdump enabled kernel panics, it immediately boots into a clean kernel called the kdump kernel. The memory image of the panicked kernel will be presented in /proc/vmcore while the kdump kernel (or "capture kernel") is running.

kdump-config loads the kdump kernel into the current kernel and after a kdump, captures the vmcore image via kdump kernel. kdump-config can take advantage of the linux-image-$(uname -r)-dbg package and will try to use makedumpfile to capture the vmcore. The crash tool can then be used to analyze the vmcore at a later time.

kdump-config exits with 0 on success and 1 on failure.



Print a usage summary.


Determine the parameters that would be used to load the kdump kernel, but do not load the kdump kernel. Useful for evaluating your configuration settings.


Show current parameters and the saved kexec command from the last kdump-config load.


Evaluate /sys/kernel/kexec_crash_loaded and print a corresponding message.


Load the kdump kernel.


Unload the kdump kernel.


If /proc/vmcore exists, save it using makedumpfile.



init script to automatically load a kdump kernel, or save a vmcore and reboot.


configuration file


a link to the current debug kernel


the last kexec_cmd executed by kdump-config


USE_KDUMP is not set or zero

The variable USE_KDUMP in the file /etc/default/kdump-tools is 0. To use kdump, edit the file and change the value to 1.

kdump is not supported by this kernel

The file /sys/kernel/kexec_crash_loaded does not exist. This means that the currently running kernel either was not configured to support kdump, or that a crashkernel= commandline parameter was not used when the currently running kernel booted.

no crashkernel= parameter in the kernel cmdline

a crashkernel= commandline parameter was not used when the currently running kernel booted. You will need to add a crashkernel= parameter to your /etc/lilo.conf, /etc/elilo.conf or grub /boot/grub/menu.lst file and reboot, before kdump will work. See installed READMEs for suggestions.

could not find an installed debug vmlinux image and
DEBUG_KERNEL is not specified in /etc/default/kdump-tools
Warning: makedumpfile will be limited to -d 1.

A debug version of the currently booted kernel could not be found.


A KDUMP_KERNEL was specified in /etc/default/kdump-tools, but it cannot be found.


A KDUMP_INITRD was specified in /etc/default/kdump-tools, but it cannot be found.

can't find a kdump package directory in /usr/lib

no kdump kernel could be found.

found a linux-kdump package in $KDUMP_PKG_DIR
but can't find a kdump kernel in $KDUMP_PKG_DIR

this indicates a broken linux-kdump package installation.

no kdump initrd image: $KDUMP_INITRD
an initrd will not be used

this indicates that although a kdump kernel was found, a corresponding initrd was not found.

kdump kernel relocation address does not match crashkernel= parameter

For non-relocatable architectures, the kdump kernel must be built with a predetermined start address. This message indicates that the start address of the kdump kernel and the start address in the crashkernel= parameter do not match.

failed to load kdump kernel

kexec reported that it could not load the kdump kernel.

failed to unload kdump kernel

kexec reported that it could not unload the kdump kernel. Run 'kexec -u' directly for more detail.

makedumpfile failed, falling back to 'cp'

this message is printed if the kdump-tools init script attempts to save a /proc/vmcore file using makedumpfile and the save fails.

failed to save vmcore in $KDUMP_STAMPDIR

this message indicates that makedumpfile and the fallback method of using cp has failed. This usually occurs if pathnames are wrong or if the disk is full.

RELATED TO kdump-config…



kdump-tools(5), kexec(8), crash(8), gdb(1), makedumpfile(8)


Terry Loftin <[email protected]>