From b9f1f1ce866c28e3d9b86202441b220244754a69 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 16 Oct 2017 19:38:35 -0700 Subject: [PATCH] tcp: fix tcp_xmit_retransmit_queue() after rbtree introduction I tried to hard avoiding a call to rb_first() (via tcp_rtx_queue_head) in tcp_xmit_retransmit_queue(). But this was probably too bold. Quoting Yuchung : We might miss re-arming the RTO if tp->retransmit_skb_hint is not NULL. This can happen when RACK marks the first packet lost again and resets tp->retransmit_skb_hint for example (tcp_rack_mark_skb_lost()) Fixes: 75c119afe14f ("tcp: implement rb-tree based retransmit queue") Signed-off-by: Eric Dumazet Reported-by: Yuchung Cheng Signed-off-by: David S. Miller --- net/ipv4/tcp_output.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 6c74f2a39778..53dc1267c85e 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2921,7 +2921,7 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs) void tcp_xmit_retransmit_queue(struct sock *sk) { const struct inet_connection_sock *icsk = inet_csk(sk); - struct sk_buff *skb, *rtx_head = NULL, *hole = NULL; + struct sk_buff *skb, *rtx_head, *hole = NULL; struct tcp_sock *tp = tcp_sk(sk); u32 max_segs; int mib_idx; @@ -2929,11 +2929,8 @@ void tcp_xmit_retransmit_queue(struct sock *sk) if (!tp->packets_out) return; - skb = tp->retransmit_skb_hint; - if (!skb) { - rtx_head = tcp_rtx_queue_head(sk); - skb = rtx_head; - } + rtx_head = tcp_rtx_queue_head(sk); + skb = tp->retransmit_skb_hint ?: rtx_head; max_segs = tcp_tso_segs(sk, tcp_current_mss(sk)); skb_rbtree_walk_from(skb) { __u8 sacked; -- 2.39.5