diff -urNp a/net/bridge/br_stp_bpdu.c b/net/bridge/br_stp_bpdu.c
--- a/net/bridge/br_stp_bpdu.c	2013-10-18 21:44:19.000000000 +0400
+++ b/net/bridge/br_stp_bpdu.c	2013-11-11 11:33:22.683549616 +0400
@@ -152,10 +152,10 @@ void br_stp_rcv(const struct stp_proto *
 	buf = skb->data;
 	if (buf[0] != 0 || buf[1] != 0 || buf[2] != 0)
 		goto err;
+	if (!br_port_exists(dev))
+		goto err;
 
 	p = br_port_get_rcu(dev);
-	if (!p)
-		goto err;
 
 	br = p->br;
 	spin_lock(&br->lock);