Another app is currently holding the yum lock; waiting for it to exit

yum Another app is currently holding the yum lock; waiting for it to exit
Another app is currently holding the yum lock; waiting for it to exit
Another app is currently holding the yum lock; waiting for it to exit...

not able to install rpm on centos


[root@apt-jtime-01 tmp]# yum install libXp

Loaded plugins: fastestmirror
Existing lock /var/run/yum.pid: another copy is running as pid 2455.
Another app is currently holding the yum lock; waiting for it to exit...
The other application is: yum
Memory : 38 M RSS ( 80 MB VSZ)
Started: Thu Jun 9 15:32:06 2011 - 3 day(s) 19:31:05 ago
State : Sleeping, pid: 2455

Another app is currently holding the yum lock; waiting for it to exit...




Exiting on user cancel.

check the process

[root@apt-jtime-01 tmp]# ps aux | grep yum
root 2383 0.0 1.0 25908 10404 ? SN Jun09 0:00 /usr/bin/python -tt /usr/sbin/yum-updatesd
root 2455 0.0 3.8 81496 39036 tty1 S+ Jun09 0:35 /usr/bin/python /usr/bin/yum upgrade
root 31788 0.0 0.0 4016 708 pts/0 S+ 11:04 0:00 grep yum

[root@apt-jtime-01 tmp]# kill -9 2383 2455


then try again