Package require to analyze kernel core dump in RHEL system

To analyze the system crash dump file (vmcore) , we must have crash and debuginfo package installed on system. 

To install the crash package in your system, run the following as root:

#yum install crash

To install the kernel-debuginfo package, make sure that you have the yum-utils package installed and run the following command as root:

#debuginfo-install kernel

If not able to download the debuginfo kernel package with above command, then download the package from ftp server: http://ftp.heanet.ie/mirrors/puias/updates/


For example to download the RHEL6 (32-bit) related debuginfo package from:
http://ftp.heanet.ie/mirrors/puias/updates/6Server/en/os/debug/i386/

For example to download the RHEL6 (64-bit) related debuginfo package from:
http://ftp.heanet.ie/mirrors/puias/updates/6Server/en/os/debug/x86_64/


Package need to download:
1) Determine the kernel version of generated "vmcore" system , by executing "uname -r" command
2) Download the kernel-debuginfo-`uname -r`.rpm and kernel-debuginfo-common-`uname -r`.rpm
3) Install the package through rpm command i.e "rpm -ivh <package name>

Printk Timestamp Enable Method

We can enable and disable printk timestamps at runtime, by writing to /sys/module/printk/parameters/time.

By default printk timestamp is disable : 

[root@localhost ~]# cat /sys/module/printk/parameters/time

N

In order to enable the printk timestamp execute the below command:

[root@localhost ~]# echo "1" > /sys/module/printk/parameters/time

[root@localhost ~]# cat /sys/module/printk/parameters/time

Y

[root@localhost ~]# dmesg

[11320.847977] Hello World..

After that will able to see the timestamp. 

In order to disable to printk timestamp execute the below command

[root@localhost ~]# echo "0" > /sys/module/printk/parameters/time

[root@localhost ~]# cat /sys/module/printk/parameters/time

N