What's the approach to figure out reason for mysql crash?
This appears to be a regression bug that exists in Percona Server 5.6.14 and possibly some previous versions of 5.6.
https://bugs.launchpad.net/percona-server/+bug/1247021
It appears it was fixed in Percona Server 5.6.16-64.0:

Due to a regression in the buffer pool mutex split, a combination of InnoDB compression, write workload, and multiple active purge threads could lead to a server crash. Bug fixed #1247021.
— http://www.percona.com/doc/percona-server/5.6/release-notes/Percona-Server-5.6.16-64.0.html