From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757349AbaITQvr (ORCPT ); Sat, 20 Sep 2014 12:51:47 -0400 Received: from forward10l.mail.yandex.net ([84.201.143.143]:40887 "EHLO forward10l.mail.yandex.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757178AbaITQvn (ORCPT ); Sat, 20 Sep 2014 12:51:43 -0400 X-Yandex-Uniq: 9b88e02b-91df-4ad5-bdbe-18ad38fa216b Authentication-Results: smtp4h.mail.yandex.net; dkim=pass header.i=@yandex.ru Subject: [PATCH 5/7] sched: Use rq->rd in sched_setaffinity() under RCU read lock From: Kirill Tkhai To: linux-kernel@vger.kernel.org Cc: Peter Zijlstra , Ingo Molnar , Kirill Tkhai Date: Sat, 20 Sep 2014 20:51:40 +0400 Message-ID: <20140920165140.16299.45521.stgit@localhost> In-Reply-To: <20140920165116.16299.1381.stgit@localhost> References: <20140920165116.16299.1381.stgit@localhost> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Kirill Tkhai task_rq(p)->rd and task_rq(p)->rd->span may be used-after-free here. Probability of NULL pointer derefference isn't zero in this place. Signed-off-by: Kirill Tkhai Cc: # v3.14+ --- kernel/sched/core.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 65655a887..a40d6e1 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -4015,13 +4015,14 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) * root_domain. */ #ifdef CONFIG_SMP - if (task_has_dl_policy(p)) { - const struct cpumask *span = task_rq(p)->rd->span; - - if (dl_bandwidth_enabled() && !cpumask_subset(span, new_mask)) { + if (task_has_dl_policy(p) && dl_bandwidth_enabled()) { + rcu_read_lock(); + if (!cpumask_subset(task_rq(p)->rd->span, new_mask)) { retval = -EBUSY; + rcu_read_unlock(); goto out_free_new_mask; } + rcu_read_unlock(); } #endif again: