Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Subash Abhinov Kasiviswanathan , Sami Farin , Eric Dumazet , Soheil Hassas Yeganeh , Yuchung Cheng , Neal Cardwell , "David S. Miller" Subject: [PATCH 4.16 27/81] tcp: clear tp->packets_out when purging write queue Date: Fri, 27 Apr 2018 15:58:29 +0200 Message-Id: <20180427135744.708942422@linuxfoundation.org> In-Reply-To: <20180427135743.216853156@linuxfoundation.org> References: <20180427135743.216853156@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Soheil Hassas Yeganeh [ Upstream commit bffd168c3fc5cc7d2bad4c668fa90e7a9010db4b ] Clear tp->packets_out when purging the write queue, otherwise tcp_rearm_rto() mistakenly assumes TCP write queue is not empty. This results in NULL pointer dereference. Also, remove the redundant `tp->packets_out = 0` from tcp_disconnect(), since tcp_disconnect() calls tcp_write_queue_purge(). Fixes: a27fd7a8ed38 (tcp: purge write queue upon RST) Reported-by: Subash Abhinov Kasiviswanathan Reported-by: Sami Farin Tested-by: Sami Farin Signed-off-by: Eric Dumazet Signed-off-by: Soheil Hassas Yeganeh Acked-by: Yuchung Cheng Acked-by: Neal Cardwell Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/tcp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2385,6 +2385,7 @@ void tcp_write_queue_purge(struct sock * INIT_LIST_HEAD(&tcp_sk(sk)->tsorted_sent_queue); sk_mem_reclaim(sk); tcp_clear_all_retrans_hints(tcp_sk(sk)); + tcp_sk(sk)->packets_out = 0; } int tcp_disconnect(struct sock *sk, int flags) @@ -2434,7 +2435,6 @@ int tcp_disconnect(struct sock *sk, int icsk->icsk_backoff = 0; tp->snd_cwnd = 2; icsk->icsk_probes_out = 0; - tp->packets_out = 0; tp->snd_ssthresh = TCP_INFINITE_SSTHRESH; tp->snd_cwnd_cnt = 0; tp->window_clamp = 0;