Commit d832269a authored Jan 16, 2019 by Yuchung Cheng Committed by Greg Kroah-Hartman Dec 05, 2019

tcp: exit if nothing to retransmit on RTO timeout



commit 88f8598d0a302a08380eadefd09b9f5cb1c4c428 upstream.

Previously TCP only warns if its RTO timer fires and the
retransmission queue is empty, but it'll cause null pointer
reference later on. It's better to avoid such catastrophic failure
and simply exit with a warning.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 95442682

net/ipv4/tcp_timer.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -443,10 +443,8 @@ void tcp_retransmit_timer(struct sock *sk)
		*/
		return;
		}
		if (!tp->packets_out)
		goto out;

		WARN_ON(tcp_rtx_queue_empty(sk));
		if (!tp->packets_out \|\| WARN_ON_ONCE(tcp_rtx_queue_empty(sk)))
		return;

		tp->tlp_high_seq = 0;