From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Bligh Subject: Re: [PATCH] netfilter: fix ->nfnl NULL oops Date: Wed, 09 Nov 2011 19:06:13 +0000 Message-ID: <739793C1875DFFB8AD91547F@nimrod.local> References: <20111108221634.GA13261@p183.telecom.by> <20111109143423.GA24158@1984> Reply-To: Alex Bligh Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: kaber@trash.net, netfilter-devel@vger.kernel.org, Alex Bligh To: Pablo Neira Ayuso , Alexey Dobriyan Return-path: Received: from mail.avalus.com ([89.16.176.221]:45159 "EHLO mail.avalus.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751217Ab1KITGP (ORCPT ); Wed, 9 Nov 2011 14:06:15 -0500 In-Reply-To: <20111109143423.GA24158@1984> Content-Disposition: inline Sender: netfilter-devel-owner@vger.kernel.org List-ID: --On 9 November 2011 15:34:23 +0100 Pablo Neira Ayuso wrote: >> I recall myself writing that net->nfnl NULL check is racy or >> something like that (but I can't find this email in archives). >> >> I've read the code once again, and I'm quite sure, >> NULL ->nfnl check is correct if RCU precautions are made. >> >> Regarding ->report check, I think it's bogus. >> >> If there are no listeners, there are NO listeners >> and whether to report back to userspace doesn't matter. >> >> I'm sure I'm missing something obvious here. >> >> Please, review. > > Alexey. This is a workaround. We have to make ctnl_notifier > container-aware which is the real problem. It is indeed a workaround. However, until we have a real solution, we need a workaround, or we can trivially generate fatal oopses. I am all for fixing it properly, but please can we leave the workaround in place until we have the proper answer, as without this we see machines die frequently. -- Alex Bligh