From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S938587AbcKNC5H (ORCPT ); Sun, 13 Nov 2016 21:57:07 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:47094 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933529AbcKNCYR (ORCPT ); Sun, 13 Nov 2016 21:24:17 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Zefan Li" , "Tejun Heo" Date: Mon, 14 Nov 2016 00:14:20 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 166/346] cpuset: make sure new tasks conform to the current config of the cpuset In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.39-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Zefan Li commit 06f4e94898918bcad00cdd4d349313a439d6911e upstream. A new task inherits cpus_allowed and mems_allowed masks from its parent, but if someone changes cpuset's config by writing to cpuset.cpus/cpuset.mems before this new task is inserted into the cgroup's task list, the new task won't be updated accordingly. Signed-off-by: Zefan Li Signed-off-by: Tejun Heo [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- kernel/cpuset.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -1963,6 +1963,20 @@ static void cpuset_css_free(struct cgrou kfree(cs); } +/* + * Make sure the new task conform to the current state of its parent, + * which could have been changed by cpuset just after it inherits the + * state from the parent and before it sits on the cgroup's task list. + */ +void cpuset_fork(struct task_struct *task) +{ + if (task_css_is_root(task, cpuset_cgrp_id)) + return; + + set_cpus_allowed_ptr(task, ¤t->cpus_allowed); + task->mems_allowed = current->mems_allowed; +} + struct cgroup_subsys cpuset_cgrp_subsys = { .css_alloc = cpuset_css_alloc, .css_online = cpuset_css_online, @@ -1971,6 +1985,7 @@ struct cgroup_subsys cpuset_cgrp_subsys .can_attach = cpuset_can_attach, .cancel_attach = cpuset_cancel_attach, .attach = cpuset_attach, + .fork = cpuset_fork, .base_cftypes = files, .early_init = 1, };