Commit 32a44f1b authored by WANG Cong's avatar WANG Cong Committed by Greg Kroah-Hartman

tcp: reset sk_rx_dst in tcp_disconnect()

commit d747a7a5 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: 41063e9d ("ipv4: Early TCP socket demux.")
Reported-by: default avatarAndrei Vagin <avagin@gmail.com>
Reported-by: default avatarKevin Xu <kaiwen.xu@hulu.com>
Signed-off-by: default avatarCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent ccff2f4a
...@@ -2263,6 +2263,8 @@ int tcp_disconnect(struct sock *sk, int flags) ...@@ -2263,6 +2263,8 @@ int tcp_disconnect(struct sock *sk, int flags)
tcp_init_send_head(sk); tcp_init_send_head(sk);
memset(&tp->rx_opt, 0, sizeof(tp->rx_opt)); memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
__sk_dst_reset(sk); __sk_dst_reset(sk);
dst_release(sk->sk_rx_dst);
sk->sk_rx_dst = NULL;
tcp_saved_syn_free(tp); tcp_saved_syn_free(tp);
WARN_ON(inet->inet_num && !icsk->icsk_bind_hash); WARN_ON(inet->inet_num && !icsk->icsk_bind_hash);
......
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