How to generate and analyze a crash dump on Redhat Enterprise Linux

This is a guide on how to gather a crash dump on RHEL systems.

First, install the following packages:

# yum install kexec-tools crash kernel-debuginfo kernel-debuginfo-common system-config-kdump
In graphical mode:

# system-config-kdump In the target settings tab:
Select the appropiate Path: and Partition Values.
Click Apply.
Reboot the system.In console mode:
Edit the /boot/grub/menu.lst file:Add “crashkernel=128M” to the kernel line:
kernel /boot/vmlinuz-2.6.32-54.el6.i686 root=/dev/sda3 ro crashkernel=128M

Modify the config file: /etc/kdump.conf

Modify these values for where the core file should be stored:

ext3 /dev/sda4
path /var/core

Save and reboot the system

Capture the core: (This will panic the system and will take a long time to complete)
# echo c > /proc/sysrq-trigger    Locate the core:
# ls /var/crash    Analyze the core:
# crash /var/crash/2012-03-29/vmcore /usr/lib/debug/lib/modules/`uname -r`/vmlinux        Available Commands:
crash> sys
crash> bt -a
crash> mod
crash> log
crash> sys