Comment 2 for bug 1471101

Here walk was started on a table which was deleted. This is in control of agent as route table was deleted by same under vrf delete, however it does not reset the table pointer to NULL. Now if a walk is started on this VRF (to delete state if any) then seeing this non NULL pointer, walker starts a route table walk as well which eventually crashes.
Solution can be to maintain a bitmap of non-deleted route tables for VRF. To use route table pointer this bitset should be consulted before any operation is started.