From: David L Stevens <david.stevens@oracle.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Miller <davem@davemloft.net>, netdev@vger.kernel.org
Subject: Re: [PATCH net-next] sunvnet: don't change gso data on clones
Date: Wed, 11 Feb 2015 22:17:19 -0500 [thread overview]
Message-ID: <54DC1B3F.8000507@oracle.com> (raw)
In-Reply-To: <1423709570.4847.21.camel@edumazet-glaptop2.roam.corp.google.com>
Yes, I've seen that patch. The bug I'm fixing has the same symptoms,
but the mangling is being done by the sunvnet driver and the fix is
the same-- don't mangle packets that are cloned (and unclone them if you
need to mangle them).
The original sunvnet code changed gso_size temporarily, but that still
had a race where TCP could see the driver-modified gso_size with low probability
and end up with a negative packets-in-flight.
The unclone removes that bug, created (by me) after your fix, but in the sunvnet driver
with the addition of TSO support.
+-DLS
On 02/11/2015 09:52 PM, Eric Dumazet wrote:
>
> Well, we had a very hard to find bug in TCP stack, I want to make sure
> we fixed all relevant points.
>
> commit c52e2421f7368fd36cbe330d2cf41b10452e39a9
> Author: Eric Dumazet <edumazet@google.com>
> Date: Tue Oct 15 11:54:30 2013 -0700
>
> tcp: must unclone packets before mangling them
>
> TCP stack should make sure it owns skbs before mangling them.
...
next prev parent reply other threads:[~2015-02-12 3:17 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-11 13:20 [PATCH net-next] sunvnet: don't change gso data on clones David L Stevens
2015-02-11 13:56 ` Eric Dumazet
2015-02-11 17:35 ` David L Stevens
2015-02-12 2:52 ` Eric Dumazet
2015-02-12 3:17 ` David L Stevens [this message]
2015-02-12 3:06 ` Eric Dumazet
2015-02-12 3:41 ` David Miller
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