From: David Miller <davem@davemloft.net>
To: kafai@fb.com
Cc: netdev@vger.kernel.org, kernel-team@fb.com, edumazet@google.com,
ncardwell@google.com, soheil.kdev@gmail.com, willemb@google.com,
ycheng@google.com
Subject: Re: [PATCH net] tcp: Fix SOF_TIMESTAMPING_TX_ACK when handling dup acks
Date: Thu, 21 Apr 2016 13:46:26 -0400 (EDT) [thread overview]
Message-ID: <20160421.134626.1196772506489683431.davem@davemloft.net> (raw)
In-Reply-To: <1461019193-3034571-1-git-send-email-kafai@fb.com>
From: Martin KaFai Lau <kafai@fb.com>
Date: Mon, 18 Apr 2016 15:39:53 -0700
> Assuming SOF_TIMESTAMPING_TX_ACK is on. When dup acks are received,
> it could incorrectly think that a skb has already
> been acked and queue a SCM_TSTAMP_ACK cmsg to the
> sk->sk_error_queue.
>
> In tcp_ack_tstamp(), it checks
> 'between(shinfo->tskey, prior_snd_una, tcp_sk(sk)->snd_una - 1)'.
> If prior_snd_una == tcp_sk(sk)->snd_una like the following packetdrill
> script, between() returns true but the tskey is actually not acked.
> e.g. try between(3, 2, 1).
>
> The fix is to replace between() with one before() and one !before().
> By doing this, the -1 offset on the tcp_sk(sk)->snd_una can also be
> removed.
...
> Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Applied, thank you.
prev parent reply other threads:[~2016-04-21 17:46 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-18 22:39 [PATCH net] tcp: Fix SOF_TIMESTAMPING_TX_ACK when handling dup acks Martin KaFai Lau
2016-04-19 13:54 ` Soheil Hassas Yeganeh
2016-04-20 19:11 ` Soheil Hassas Yeganeh
2016-04-21 17:46 ` David Miller [this message]
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