Commit 
79b16aadea32cce077
("udp_tunnel: Pass UDP socket down through udp_tunnel{, 6}_xmit_skb()")
introduce 'sk' but we already have one inner 'sk'.
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
 
                iptunnel_xmit_stats(err, &dev->stats, dev->tstats);
 #if IS_ENABLED(CONFIG_IPV6)
        } else {
-               struct sock *sk = vxlan->vn_sock->sock->sk;
                struct dst_entry *ndst;
                struct flowi6 fl6;
                u32 flags;