From mboxrd@z Thu Jan 1 00:00:00 1970 From: Li Zefan Subject: Re: [BUG] Bug in netprio_cgroup and netcls_cgroup ? Date: Mon, 21 Jan 2013 17:01:54 +0800 Message-ID: <50FD0402.6060400@huawei.com> References: <50FCDB5C.4050608@huawei.com> <50FD0144.1000401@monom.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <50FD0144.1000401-kQCPcA+X3s7YtjvyW6yDsg@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Daniel Wagner Cc: John Fastabend , Neil Horman , Daniel Wagner , LKML , netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Cgroups On 2013/1/21 16:50, Daniel Wagner wrote: > Hi Li, > > On 21.01.2013 07:08, Li Zefan wrote: >> I'm not a network developer, so correct me if I'm wrong. >> >> Since commit 7955490f732c2b8 >> ("net: netprio_cgroup: rework update socket logic"), sock->sk->sk_cgrp_prioidx >> is set when the socket is created, and won't be updated unless the task is >> moved to another cgroup. >> >> Now the problem is, a socket can be _shared_ by multiple processes (fork, SCM_RIGHT). >> If we place those processes in different cgroups, and each cgroup has >> different configs, but all of the processes will send data via this socket >> with the same network priority. > > Wouldn't that be addressed by 48a87cc26c13b68f6cce4e9d769fcb17a6b3e4b8 > > net: netprio: fd passed in SCM_RIGHTS datagram not set correctly > > A socket fd passed in a SCM_RIGHTS datagram was not getting > updated with the new tasks cgrp prioidx. This leaves IO on > the socket tagged with the old tasks priority. > > To fix this add a check in the scm recvmsg path to update the > sock cgrp prioidx with the new tasks value. > > As I read this this should work for net_prio. > But after process A passed the socket fd to B, both A and B can use the same socket to send data, right? Then if A and B were placed in different cgroups with differnt configs, A's config won't take effect anymore. Am I missing something?