4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Soheil Hassas Yeganeh <soheil@xxxxxxxxxx> [ 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 <subashab@xxxxxxxxxxxxxx> Reported-by: Sami Farin <hvtaifwkbgefbaei@xxxxxxxxx> Tested-by: Sami Farin <hvtaifwkbgefbaei@xxxxxxxxx> Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx> Signed-off-by: Soheil Hassas Yeganeh <soheil@xxxxxxxxxx> Acked-by: Yuchung Cheng <ycheng@xxxxxxxxxx> Acked-by: Neal Cardwell <ncardwell@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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;