On Fri, 2017-01-13 at 18:01 +0300, Alexey Kodanev wrote:
> Hi,
> Got the issue when running LTP/netstress test on localhost with mss
> greater than the send window advertised by client (right after 3WHS).
> Here is the testscenario that can reproduce this:

Hi Alexey

So this is a combination of Fastopen + small window + large MSS ?

I would rather not force burning tons of coal or other fossil fuel,
by making each tcp_sendmsg() done by billions of linux devices more
expensive, only to accommodate for some LTP test doing something not
sensible ;)

Fact that you removed one condition in the BUG_ON() might hide another
issue later in the path.

I would suggest to clamp MSS to half the initial window, but I guess
this is impractical since window in SYN/SYNACK are not scaled.

Care to send a packetdrill test so that we have a clear picture of what
is going on ?


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