From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: 3.9.5+:  Crash in tcp_input.c:4810.
Date: Tue, 02 Jul 2013 22:02:29 -0700
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To: Ben Greear <greearb@candelatech.com>
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On Tue, 2013-07-02 at 21:49 -0700, Ben Greear wrote:

> Well, network emulators are easy to come by in the office....  Maybe running
> a bunch of TCP connections through a lossy network would exercise this code
> path a bit?  Aside from random pkt loss, any other types of network conditions
> that might help trigger this faster?
> 
> I'll set up some tests using some wired ethernet...if we can trigger it there
> then we at least know it doesn't depend on ath9k...

I tried a lot of things, including netem with many reorders and/or
packetdrill tests, but so far not a single warning from tcp_collapse()