| From | Ben Hutchings <> | Date | Sat, 09 Sep 2017 22:47:15 +0100 | Subject | [PATCH 3.16 219/233] tcp: reset sk_rx_dst in tcp_disconnect() |
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3.16.48-rc1 review patch. If anyone has any objections, please let me know.
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From: WANG Cong <xiyou.wangcong@gmail.com>
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@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> [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- net/ipv4/tcp.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2367,6 +2367,8 @@ 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);
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