From d747a7a51b00984127a88113cdbbc26f91e9d815 Mon Sep 17 00:00:00 2001 From: WANG Cong Date: Sat, 24 Jun 2017 23:50:30 -0700 Subject: [PATCH] tcp: reset sk_rx_dst in tcp_disconnect() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Reported-by: Kevin Xu Signed-off-by: Cong Wang Signed-off-by: David S. Miller Signed-off-by: Fabian Grünbichler --- net/ipv4/tcp.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index b5ea036ca781..40aca7803cf2 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2330,6 +2330,8 @@ 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; tcp_saved_syn_free(tp); /* Clean up fastopen related fields */ -- 2.11.0