From: Thomas Graf <tgraf@suug.ch>
To: davem@davemloft.net
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH] net: Convert skb->csum_(start|offset) integrity BUG_ON() to WARN_ON() & drop
Date: Wed, 13 Feb 2013 23:48:43 +0000 [thread overview]
Message-ID: <20130213234843.GB21829@casper.infradead.org> (raw)
In-Reply-To: <20130213234021.GA21829@casper.infradead.org>
On 02/13/13 at 11:40pm, Thomas Graf wrote:
> They have been hit with IPoIB which uses a 64K MTU. If a TCP
> retransmission gets partially ACKed and collapsed multiple times
> it is possible for the headroom to grow beyond 64K which will
> overflow the 16bit skb->csum_start.
On the subject of fixing this, I considered:
a) Reallocate the headroom in tcp_trim_head() if it would
overflow. I disregarded this idea because replacing the
old skb with the new skb on the write queue for such a
rare situation seems overkill.
b) No longer collapse if the new skb would result in a
a headroom + data that exceeds 64K. This seems to be the
most trivial fix.
c) Increase size of csum_start or store checksum_start_offset
differently.
Other ideas?
next prev parent reply other threads:[~2013-02-13 23:48 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-13 23:40 [PATCH] net: Convert skb->csum_(start|offset) integrity BUG_ON() to WARN_ON() & drop Thomas Graf
2013-02-13 23:48 ` Thomas Graf [this message]
2013-02-14 0:37 ` David Miller
2013-02-14 10:18 ` Thomas Graf
2013-02-14 16:22 ` Eric Dumazet
2013-02-14 18:50 ` Thomas Graf
2013-02-14 19:21 ` Eric Dumazet
2013-02-14 18:00 ` David Miller
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