Request is based on the following discussion on linux-nfs mailing list.
http://thread.gmane.org/gmane.linux.nfs/46234

On a NFS client using kerberos authentication, when a user access the NFS share, the kernel obtains the user credentials to use for the NFS share by making an upcall to the rpc.gssd daemon. These credentials are then stored in the kernel cache and used by the nfs module when the uid accesses the NFS share.

Trying to destroy the user credentials using a kdestroy will only destroy the credentials in userspace. The user's credentials cached in the kernel will still be used when a process with the user's uid accesses the NFS share.This is a security issue since the credentials will be used even after the user has requested that the credentials be destroyed with a kdestroy.

This RFE is request to have gss-proxy delete the credentials stored in the kernel when the credentials are explicitly destroyed in userspace.