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    SubjectRe: [BACKPORT 4.4.y 18/25] tcp/dccp: drop SYN packets if accept queue is full
    On Fri, Mar 22, 2019 at 04:44:09PM +0100, Arnd Bergmann wrote:
    > From: Eric Dumazet <edumazet@google.com>
    >
    > Per listen(fd, backlog) rules, there is really no point accepting a SYN,
    > sending a SYNACK, and dropping the following ACK packet if accept queue
    > is full, because application is not draining accept queue fast enough.
    >
    > This behavior is fooling TCP clients that believe they established a
    > flow, while there is nothing at server side. They might then send about
    > 10 MSS (if using IW10) that will be dropped anyway while server is under
    > stress.
    >
    > Signed-off-by: Eric Dumazet <edumazet@google.com>
    > Acked-by: Neal Cardwell <ncardwell@google.com>
    > Acked-by: Yuchung Cheng <ycheng@google.com>
    > Signed-off-by: David S. Miller <davem@davemloft.net>
    > (cherry picked from commit 5ea8ea2cb7f1d0db15762c9b0bb9e7330425a071)

    Also queued up for 4.9.y

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