[SCTP]: Check for NULL arg to sctp_bucket_destroy().

Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp/socket.c

@@ -4977,7 +4977,7 @@ static struct sctp_bind_bucket *sctp_bucket_create(
 /* Caller must hold hashbucket lock for this tb with local BH disabled */
 static void sctp_bucket_destroy(struct sctp_bind_bucket *pp)
 {
-	if (hlist_empty(&pp->owner)) {
+	if (pp && hlist_empty(&pp->owner)) {
 		if (pp->next)
 			pp->next->pprev = pp->pprev;
 		*(pp->pprev) = pp->next;