From: David Miller <davem@davemloft.net>
To: herbert@gondor.apana.org.au
Cc: shemminger@osdl.org, guichaz@yahoo.fr, netdev@vger.kernel.org
Subject: Re: [PATCH] clear skb cb on IP input
Date: Sun, 16 Jul 2006 18:18:09 -0700 (PDT) [thread overview]
Message-ID: <20060716.181809.71092089.davem@davemloft.net> (raw)
In-Reply-To: <20060716220350.GB30090@gondor.apana.org.au>
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Mon, 17 Jul 2006 08:03:50 +1000
> The thing is qdiscs using cb means that this method of clearing cb
> before netif_rx doesn't work anymore.
>
> In particular, even if loopback clears cb before calling netif_rx,
> some qdisc could come along between netif_rx and ip_rcv and put
> stuff in the cb.
>
> The same thing can happen to any NIC in fact, as long as we allow
> qdiscs to use the cb area without clearing it, ip_rcv needs to
> clear it itself.
Ok, I'm convinced that IPv4 has to clear this out and shouldn't
assume it's contents are anything but garbage.
> With a little bit of effort we should be able to get away with
> clearing just optlen. Whether this effort is worthwhile I don't
> know :)
It all sits in the same cacheline, so probably not.
prev parent reply other threads:[~2006-07-17 1:17 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-07-14 14:34 Netem does not work with loopback Guillaume Chazarain
2006-07-14 15:38 ` Stephen Hemminger
2006-07-14 17:04 ` Guillaume Chazarain
2006-07-14 18:39 ` Stephen Hemminger
2006-07-14 18:49 ` Guillaume Chazarain
2006-07-14 18:56 ` [PATCH] clear skb cb on IP input Stephen Hemminger
2006-07-14 21:48 ` David Miller
2006-07-15 13:28 ` Herbert Xu
2006-07-15 15:50 ` Stephen Hemminger
2006-07-16 1:15 ` David Miller
2006-07-16 1:12 ` David Miller
2006-07-16 11:20 ` chas williams - CONTRACTOR
2006-07-17 2:02 ` David Miller
2006-07-18 18:19 ` Guillaume Chazarain
2006-07-18 19:43 ` Herbert Xu
2006-07-19 12:35 ` Guillaume Chazarain
2006-07-25 6:45 ` David Miller
2006-07-16 22:03 ` Herbert Xu
2006-07-17 1:18 ` David Miller [this message]
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