From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757147Ab3BQXH7 (ORCPT ); Sun, 17 Feb 2013 18:07:59 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:45632 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754887Ab3BQWzE (ORCPT ); Sun, 17 Feb 2013 17:55:04 -0500 Message-Id: <20130217225002.379301902@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Sun, 17 Feb 2013 22:50:07 +0000 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: akpm@linux-foundation.org, Shawn Bohrer , Steven Rostedt , Mike Galbraith , Ingo Molnar Subject: [ 06/66] sched/rt: Use root_domain of rt_rq not current processor In-Reply-To: <20130217225001.621306883@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:a11:96ff:fec6:70c4 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 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Shawn Bohrer commit aa7f67304d1a03180f463258aa6f15a8b434e77d upstream. When the system has multiple domains do_sched_rt_period_timer() can run on any CPU and may iterate over all rt_rq in cpu_online_mask. This means when balance_runtime() is run for a given rt_rq that rt_rq may be in a different rd than the current processor. Thus if we use smp_processor_id() to get rd in do_balance_runtime() we may borrow runtime from a rt_rq that is not part of our rd. This changes do_balance_runtime to get the rd from the passed in rt_rq ensuring that we borrow runtime only from the correct rd for the given rt_rq. This fixes a BUG at kernel/sched/rt.c:687! in __disable_runtime when we try reclaim runtime lent to other rt_rq but runtime has been lent to a rt_rq in another rd. Signed-off-by: Shawn Bohrer Acked-by: Steven Rostedt Acked-by: Mike Galbraith Cc: peterz@infradead.org Link: http://lkml.kernel.org/r/1358186131-29494-1-git-send-email-sbohrer@rgmadvisors.com Signed-off-by: Ingo Molnar [bwh: Backported to 3.2: adjust filename] Signed-off-by: Ben Hutchings --- kernel/sched_rt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -384,7 +384,7 @@ static inline struct rt_bandwidth *sched static int do_balance_runtime(struct rt_rq *rt_rq) { struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq); - struct root_domain *rd = cpu_rq(smp_processor_id())->rd; + struct root_domain *rd = rq_of_rt_rq(rt_rq)->rd; int i, weight, more = 0; u64 rt_period;