From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754413Ab3AWJYf (ORCPT ); Wed, 23 Jan 2013 04:24:35 -0500 Received: from hotel311.server4you.de ([85.25.146.15]:46233 "EHLO hotel311.server4you.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753902Ab3AWJYd (ORCPT ); Wed, 23 Jan 2013 04:24:33 -0500 Message-ID: <50FFAC4F.6010602@monom.org> Date: Wed, 23 Jan 2013 10:24:31 +0100 From: Daniel Wagner User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: John Fastabend CC: Li Zefan , John Fastabend , Neil Horman , Daniel Wagner , LKML , netdev@vger.kernel.org, Cgroups Subject: Re: [BUG] Bug in netprio_cgroup and netcls_cgroup ? References: <50FCDB5C.4050608@huawei.com> <50FD0144.1000401@monom.org> <50FD0402.6060400@huawei.com> <50FD09FD.4010804@monom.org> <50FD1113.6010402@huawei.com> <50FD786E.4050108@gmail.com> <20130122100938.GA26820@candlejack.bmw-carit.intra> <50FF287C.70906@gmail.com> In-Reply-To: <50FF287C.70906@gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 23.01.2013 01:02, John Fastabend wrote: > [...] > >>> >>> OK, I guess we should do something similar in the netprio, netcls >>> cgroups and >>> yes document it as you noted in your last comment. >> >> Here is my attempt to add such a check. I really don't know if this is >> the >> correct way to do so. To test this I have written a test program, which >> seems to test the right thing. Please have a look and let me know if >> it is correct: http://www.monom.org/misc/scm_rights.c >> >> And here a dirty first version of the patch: >> >> >> From 49a78d907eaf31c16673025e7e3b4844e419e416 Mon Sep 17 00:00:00 2001 >> From: Daniel Wagner >> Date: Tue, 22 Jan 2013 11:08:22 +0100 >> Subject: [PATCH] net: net_prio: Block attach if a socket is shared >> >> --- >> net/core/netprio_cgroup.c | 30 ++++++++++++++++++++++++++++++ >> 1 file changed, 30 insertions(+) >> >> diff --git a/net/core/netprio_cgroup.c b/net/core/netprio_cgroup.c >> index 847c02b..de4e6c5 100644 >> --- a/net/core/netprio_cgroup.c >> +++ b/net/core/netprio_cgroup.c >> @@ -274,9 +274,39 @@ static struct cftype ss_files[] = { >> { } /* terminate */ >> }; >> >> +static int check_cnt(const void *v, struct file *file, unsigned n) >> +{ >> + unsigned *flag = (unsigned *)v; >> + int err; >> + >> + struct socket *sock = sock_from_file(file, &err); >> + if (sock && file_count(file) > 1) >> + *flag = 1; >> + > > I think this check will catch a lot of cases that are not necessarily > sharing a socket across tasks though. For example iscsid passes a file > descriptor to the kernel which does a sockfd_lookup() incrementing > f_count. Similarly look at dup/clone/etc. Yep, I expected that this patch was too simple. > In many of these cases I believe it should be OK to move the task > around when the sockets are not shared between multiple tasks. Do you know of a different way to identify the shared sockets? thanks, daniel