From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756915AbaITQve (ORCPT ); Sat, 20 Sep 2014 12:51:34 -0400 Received: from forward9l.mail.yandex.net ([84.201.143.142]:35978 "EHLO forward9l.mail.yandex.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752898AbaITQvc (ORCPT ); Sat, 20 Sep 2014 12:51:32 -0400 X-Yandex-Uniq: d4afbbcb-d861-40fb-8452-2983c1de25c1 Authentication-Results: smtp11.mail.yandex.net; dkim=pass header.i=@yandex.ru Subject: [PATCH 3/7] sched: Use dl_bw_of() 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 20:51:28 +0400 Message-ID: <20140920165128.16299.20888.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 dl_bw_of() dereferences rq->rd which has to have RCU read lock held. Probability of use-after-free and memory corruption aren't zero here. Signed-off-by: Kirill Tkhai Cc: # v3.14+ --- kernel/sched/core.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index c8d754f..00a024c 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -7619,6 +7619,8 @@ static int sched_dl_global_constraints(void) int cpu, ret = 0; unsigned long flags; + rcu_read_lock(); + /* * Here we want to check the bandwidth not being set to some * value smaller than the currently allocated bandwidth in @@ -7640,6 +7642,8 @@ static int sched_dl_global_constraints(void) break; } + rcu_read_unlock(); + return ret; } @@ -7655,6 +7659,7 @@ static void sched_dl_do_global(void) if (global_rt_runtime() != RUNTIME_INF) new_bw = to_ratio(global_rt_period(), global_rt_runtime()); + rcu_read_lock(); /* * FIXME: As above... */ @@ -7665,6 +7670,7 @@ static void sched_dl_do_global(void) dl_b->bw = new_bw; raw_spin_unlock_irqrestore(&dl_b->lock, flags); } + rcu_read_unlock(); } static int sched_rt_global_validate(void)