We should release dst if dst->error is set.
Bug introduced in 2.6.14 by commit 
e104411b82f5c
([XFRM]: Always release dst_entry on error in xfrm_lookup)
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Patrick McHardy <kaber@trash.net>
        fl.fl_ip_dport = otcph.source;
        security_skb_classify_flow(oldskb, &fl);
        dst = ip6_route_output(net, NULL, &fl);
-       if (dst == NULL)
+       if (dst == NULL || dst->error) {
+               dst_release(dst);
                return;
-       if (dst->error || xfrm_lookup(net, &dst, &fl, NULL, 0))
+       }
+       if (xfrm_lookup(net, &dst, &fl, NULL, 0))
                return;
 
        hh_len = (dst->dev->hard_header_len + 15)&~15;