Openstack xena - Whenever I try to extend the boot volume size in a Heat stack, the heat update gets stuck in UPDATE_IN_PROGRESS

Question

I am using openstack Heat as my backend to manage vms. Whenever I try to increase the size of the boot volume of a vm by increasing the size value of a boot volume in a heat teamplate- The stack template gets stuck in UPDATE_IN_PROGRESS, but when I use cli and directly use cinder to extend the boot volume size it gets extended. There is no log generated anywhere. What can be the reason here?