3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: WANG Cong <xiyou.wangcong@xxxxxxxxx> commit d747a7a51b00984127a88113cdbbc26f91e9d815 upstream. We have to reset the sk->sk_rx_dst when we disconnect a TCP connection, because otherwise when we re-connect it this dst reference is simply overridden in tcp_finish_connect(). This fixes a dst leak which leads to a loopback dev refcnt leak. It is a long-standing bug, Kevin reported a very similar (if not same) bug before. Thanks to Andrei for providing such a reliable reproducer which greatly narrows down the problem. Fixes: 41063e9dd119 ("ipv4: Early TCP socket demux.") Reported-by: Andrei Vagin <avagin@xxxxxxxxx> Reported-by: Kevin Xu <kaiwen.xu@xxxxxxxx> Signed-off-by: Cong Wang <xiyou.wangcong@xxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/ipv4/tcp.c | 2 ++ 1 file changed, 2 insertions(+) --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2268,6 +2268,8 @@ int tcp_disconnect(struct sock *sk, int tcp_init_send_head(sk); memset(&tp->rx_opt, 0, sizeof(tp->rx_opt)); __sk_dst_reset(sk); + dst_release(sk->sk_rx_dst); + sk->sk_rx_dst = NULL; WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);