4.14-stable review patch. If anyone has any objections, please let me know.
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From: Soheil Hassas Yeganeh soheil@google.com
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@codeaurora.org Reported-by: Sami Farin hvtaifwkbgefbaei@gmail.com Tested-by: Sami Farin hvtaifwkbgefbaei@gmail.com Signed-off-by: Eric Dumazet edumazet@google.com Signed-off-by: Soheil Hassas Yeganeh soheil@google.com Acked-by: Yuchung Cheng ycheng@google.com Acked-by: Neal Cardwell ncardwell@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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;