batman-adv: Increase orig_node refcount before releasing rcu read lock

When unicast_send_skb() is increasing the orig_node's refcount another
thread might have been freeing this orig_node already. We need to
increase the refcount in the rcu read lock protected area to avoid that.

Signed-off-by: Linus Lüssing <linus.luessing@ascom.ch>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>
diff --git a/net/batman-adv/unicast.c b/net/batman-adv/unicast.c
index 7ca994c..0603cea 100644
--- a/net/batman-adv/unicast.c
+++ b/net/batman-adv/unicast.c
@@ -293,10 +293,9 @@
 	spin_lock_bh(&bat_priv->orig_hash_lock);
 
 	/* get routing information */
-	if (is_multicast_ether_addr(ethhdr->h_dest))
+	if (is_multicast_ether_addr(ethhdr->h_dest)) {
 		orig_node = (struct orig_node *)gw_get_selected(bat_priv);
-		if (orig_node) {
-			kref_get(&orig_node->refcount);
+		if (orig_node)
 			goto find_router;
 	}