From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aristeu Rozanski Subject: Re: [PATCH 3/5] device_cgroup: keep track of local group settings Date: Thu, 29 Nov 2012 15:11:42 -0500 Message-ID: <20121129201142.GX32112@redhat.com> References: <20121127193501.255267751@napanee.usersys.redhat.com> <20121127193502.482004744@napanee.usersys.redhat.com> <20121129192945.GD26104@mail.hallyn.com> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <20121129192945.GD26104@mail.hallyn.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: "Serge E. Hallyn" Cc: linux-kernel@vger.kernel.org, Tejun Heo , Serge Hallyn , cgroups@vger.kernel.org On Thu, Nov 29, 2012 at 07:29:45PM +0000, Serge E. Hallyn wrote: > thanks for doing this. I've got one concern though. I don't see > any place where devcgroup_create() was updated to create the > local exceptions list. I think we need a guarantee that at > any time the local exceptions list will contain all the entries > contained in the cgroup->exceptions list. Otherwise you cannot > use the exception_add() the way you do (or you can't use RCU), > since there could be a window between the successful addition > of a rule to cgroup->local.exceptions and the failed addition to > cgroup->exceptions, during which a task (since it won't need > the mutex for devcg_allow()) could exceed allowed permissions. > > It's possible I'm misunderstanding. If you think that's the case > just kick me and I'll take a fresh look. > > (Btw is there a git tree or gitweb view I could look at alongside > the patchset?) ah, yes, the missing thing you're not seeing is 4b1c7840b7d01b14a1a00fa0e61b761d4391ba67 from Tejun's tree ('device_cgroup: add lockdep asserts') -- Aristeu