From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754771AbaIVScf (ORCPT ); Mon, 22 Sep 2014 14:32:35 -0400 Received: from forward8l.mail.yandex.net ([84.201.143.141]:54398 "EHLO forward8l.mail.yandex.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754654AbaIVScd (ORCPT ); Mon, 22 Sep 2014 14:32:33 -0400 X-Yandex-Uniq: b284365d-6dfe-4afa-b63e-7f5b1ab265f9 Authentication-Results: smtp4o.mail.yandex.net; dkim=pass header.i=@yandex.ru Subject: [PATCH v2 5/6] 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: Mon, 22 Sep 2014 22:32:28 +0400 Message-ID: <20140922183228.10761.72219.stgit@localhost> In-Reply-To: <20140922183202.10761.6682.stgit@localhost> References: <20140922183202.10761.6682.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 3b07710..643ee99 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -4023,13 +4023,14 @@ 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: