I believe we need to set a timeout before doing the sleep in gss-upcall.

net/sunrpc/auth_gss/auth_gss.c

@@ -348,6 +348,7 @@ gss_upcall(struct rpc_clnt *clnt, struct rpc_task *task, uid_t uid)
 	gss_new->uid = uid;
 	list_add(&gss_new->list, &gss_auth->upcalls);
 	gss_new = NULL;
+	task->tk_timeout = 5 * HZ;
 	rpc_sleep_on(&gss_msg->waitq, task, gss_release_callback, NULL);
 	spin_unlock(&gss_auth->lock);
 	res = rpc_queue_upcall(dentry->d_inode, msg);