From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) Subject: Re: [PATCH nf-next] netns: add and use net_ns_barrier Date: Wed, 31 May 2017 12:46:00 -0500 Message-ID: <87mv9skjhj.fsf@xmission.com> References: <20170530093812.10712-1-fw@strlen.de> <20170531.125527.1553231867217469072.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain Cc: fw@strlen.de, netfilter-devel@vger.kernel.org, netdev@vger.kernel.org To: David Miller Return-path: Received: from out01.mta.xmission.com ([166.70.13.231]:45615 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751034AbdEaRwt (ORCPT ); Wed, 31 May 2017 13:52:49 -0400 In-Reply-To: <20170531.125527.1553231867217469072.davem@davemloft.net> (David Miller's message of "Wed, 31 May 2017 12:55:27 -0400 (EDT)") Sender: netdev-owner@vger.kernel.org List-ID: David Miller writes: > From: Florian Westphal > Date: Tue, 30 May 2017 11:38:12 +0200 > >> Quoting Joe Stringer: >> If a user loads nf_conntrack_ftp, sends FTP traffic through a network >> namespace, destroys that namespace then unloads the FTP helper module, >> then the kernel will crash. >> >> Events that lead to the crash: >> 1. conntrack is created with ftp helper in netns x >> 2. This netns is destroyed >> 3. netns destruction is scheduled >> 4. netns destruction wq starts, removes netns from global list >> 5. ftp helper is unloaded, which resets all helpers of the conntracks >> via for_each_net() >> >> but because netns is already gone from list the for_each_net() loop >> doesn't include it, therefore all of these conntracks are unaffected. >> >> 6. helper module unload finishes >> 7. netns wq invokes destructor for rmmod'ed helper >> >> CC: "Eric W. Biederman" >> Reported-by: Joe Stringer >> Signed-off-by: Florian Westphal >> --- >> Eric, I'd like an explicit (n)ack from you for this one. > > Indeed, Eric, please do. Taking a look now. The original didn't make it's way into my inbox. I just have a copy from netdev. Florian there may be a bit of an email black hole between us. > Otherwise I'm fine with the generic parts: > > Acked-by: David S. Miller Eric