[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>
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 0a2c71d..518c55a 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -4977,7 +4977,7 @@
 /* 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;