4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Soheil Hassas Yeganeh <soheil@xxxxxxxxxx> 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: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- include/net/tcp.h | 1 + net/ipv4/tcp.c | 1 - 2 files changed, 1 insertion(+), 1 deletion(-) --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1616,6 +1616,7 @@ static inline void tcp_write_queue_purge sk_mem_reclaim(sk); tcp_clear_all_retrans_hints(tcp_sk(sk)); tcp_init_send_head(sk); + tcp_sk(sk)->packets_out = 0; } static inline struct sk_buff *tcp_write_queue_head(const struct sock *sk) --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2354,7 +2354,6 @@ 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;