From: WANG Cong xiyou.wangcong@gmail.com
This patch has been added to the stable tree. If you have any objections, please let us know.
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[ Upstream commit d747a7a51b00984127a88113cdbbc26f91e9d815 ]
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@gmail.com Reported-by: Kevin Xu kaiwen.xu@hulu.com Signed-off-by: Cong Wang xiyou.wangcong@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- net/ipv4/tcp.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 1ba4d0964042..a1de8300cfce 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2227,6 +2227,8 @@ int tcp_disconnect(struct sock *sk, int flags) 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);