From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Serge E. Hallyn" Subject: Re: [PATCH v5 9/9] devcg: propagate local changes down the hierarchy Date: Sat, 2 Feb 2013 16:20:52 +0000 Message-ID: <20130202162052.GB11284@mail.hallyn.com> References: <20130130171101.060853036@napanee.usersys.redhat.com> <20130130171102.390708521@napanee.usersys.redhat.com> <20130131043839.GA14726@mail.hallyn.com> <20130201190958.GP17632@redhat.com> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <20130201190958.GP17632-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Aristeu Rozanski Cc: "Serge E. Hallyn" , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Tejun Heo , Serge Hallyn Quoting Aristeu Rozanski (aris-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org): > +/** > + * propagate_exception - propagates a new exception to the children > + * @devcg_root: device cgroup that added a new exception > + * > + * returns: 0 in case of success, != 0 in case of error > + */ > +static int propagate_exception(struct dev_cgroup *devcg_root) > +{ > + struct cgroup *root = devcg_root->css.cgroup; > + struct dev_cgroup *devcg, *parent, *tmp; > + int rc = 0; > + LIST_HEAD(pending); > + > + get_online_devcg(root, &pending); > + > + list_for_each_entry_safe(devcg, tmp, &pending, propagate_pending) { > + parent = cgroup_to_devcgroup(devcg->css.cgroup->parent); > + > + dev_exception_clean(&devcg->exceptions); > + if (devcg->behavior == parent->behavior) { > + rc = dev_exceptions_copy(&devcg->exceptions, &parent->exceptions); Let's say parent A and child B both have DEFAULT_DENY, with a set of let's say 5 whitelist exceptions. Now the parent adds two more whitelist exceptions. As you say, we don't propagate those. Now the parent removes one of it's whitelist exceptions. devcgroup_update_access() calls dev_exception_rm() followed by propagate_exception(), which comes here and copies the parent's whitelist - including the two new whitelist rules - to the child. -serge