diff options
authorCambda Zhu <cambda@linux.alibaba.com>2019-12-27 16:52:37 +0800
committerDavid S. Miller <davem@davemloft.net>2019-12-30 20:28:39 -0800
commit853697504de043ff0bfd815bd3a64de1dce73dc7 (patch)
parentptp: fix the race between the release of ptp_clock and cdev (diff)
tcp: Fix highest_sack and highest_sack_seq
>From commit 50895b9de1d3 ("tcp: highest_sack fix"), the logic about setting tp->highest_sack to the head of the send queue was removed. Of course the logic is error prone, but it is logical. Before we remove the pointer to the highest sack skb and use the seq instead, we need to set tp->highest_sack to NULL when there is no skb after the last sack, and then replace NULL with the real skb when new skb inserted into the rtx queue, because the NULL means the highest sack seq is tp->snd_nxt. If tp->highest_sack is NULL and new data sent, the next ACK with sack option will increase tp->reordering unexpectedly. This patch sets tp->highest_sack to the tail of the rtx queue if it's NULL and new data is sent. The patch keeps the rule that the highest_sack can only be maintained by sack processing, except for this only case. Fixes: 50895b9de1d3 ("tcp: highest_sack fix") Signed-off-by: Cambda Zhu <cambda@linux.alibaba.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1 files changed, 3 insertions, 0 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 1f7735ca8f22..58c92a7d671c 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -72,6 +72,9 @@ static void tcp_event_new_data_sent(struct sock *sk, struct sk_buff *skb)
__skb_unlink(skb, &sk->sk_write_queue);
tcp_rbtree_insert(&sk->tcp_rtx_queue, skb);
+ if (tp->highest_sack == NULL)
+ tp->highest_sack = skb;
tp->packets_out += tcp_skb_pcount(skb);
if (!prior_packets || icsk->icsk_pending == ICSK_TIME_LOSS_PROBE)