netdev - Re: [PATCH net 2/4] tcp: tcp_fragment() should apply sane memory limits

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Message-ID: <CABOR3+yUiu1BzCojFQFADUKc5BT2-Ew_j7KFNpjP8WoMYZ+SMA@mail.gmail.com>
Date:   Fri, 2 Aug 2019 21:02:23 +0200
From:   Bernd <ecki@...ammenkunft.net>
To:     netdev <netdev@...r.kernel.org>
Subject: Re: [PATCH net 2/4] tcp: tcp_fragment() should apply sane memory limits

Hello,

While analyzing a aborted upload packet capture I came across a odd
trace where a sender was not responding to a duplicate SACK but
sending further segments until it stalled.

Took me some time until I remembered this fix, and actually the
problems started since the security fix was applied.

I see a high counter for TCPWqueueTooBig - and I don’t think that’s an
actual attack.

Is there a probability for triggering the limit with connections with
big windows and large send buffers and dropped segments? If so what
would be the plan? It does not look like it is configurable. The trace
seem to have 100 (filled) inflight segments.

Gruss
Bernd
-- 
http://bernd.eckenfels.net