From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Borkmann Subject: Re: [PATCH net] ipv6: mld: fix add_grhead skb_over_panic for devs with large MTUs Date: Wed, 05 Nov 2014 13:09:13 +0100 Message-ID: <545A1369.2040309@redhat.com> References: <1415149113-32668-1-git-send-email-dborkman@redhat.com> <1415149616.30247.1.camel@edumazet-glaptop2.roam.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: davem@davemloft.net, lw1a2.jing@gmail.com, fw@strlen.de, hannes@stressinduktion.org, netdev@vger.kernel.org, Eric Dumazet , David L Stevens To: Eric Dumazet Return-path: Received: from mx1.redhat.com ([209.132.183.28]:51220 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751198AbaKEMJ1 (ORCPT ); Wed, 5 Nov 2014 07:09:27 -0500 In-Reply-To: <1415149616.30247.1.camel@edumazet-glaptop2.roam.corp.google.com> Sender: netdev-owner@vger.kernel.org List-ID: On 11/05/2014 02:06 AM, Eric Dumazet wrote: > On Wed, 2014-11-05 at 01:58 +0100, Daniel Borkmann wrote: >> It has been reported that generating an MLD listener report on >> devices with large MTUs (e.g. 9000) and a high number of IPv6 >> addresses can trigger a skb_over_panic(): >> [...] >> >> Reported-by: lw1a2.jing@gmail.com >> Fixes: 72e09ad107e7 ("ipv6: avoid high order allocations") >> Signed-off-by: Daniel Borkmann >> Cc: Eric Dumazet >> Cc: David L Stevens >> --- >> In skb_nofrag_tailroom(), we could actually omit the !skb->dev check, >> but I leave that rather as a possible cleanup item for net-next. Thanks for your feedback! > Hmm... we have a proliferation of such things. > > Could you take a look at sk_stream_alloc_skb(), skb->reserved_tailroom, > and skb_availroom() ? Ok, here would be a proposal based on skb_availroom(): http://patchwork.ozlabs.org/patch/406959/ Thanks, Daniel