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From: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
To: Ingo Molnar <mingo@elte.hu>, Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH 2/2] sched_rt: protect rt_rq->rt_time by rt_runtime_lock
Date: Thu, 05 Feb 2009 15:38:10 -0800	[thread overview]
Message-ID: <498B7862.2040004@ct.jp.nec.com> (raw)
In-Reply-To: <498B77F6.4020702@ct.jp.nec.com>

From: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>

Impact: fix possible race condition

rt_rq->rt_time should be protected.

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
---
 kernel/sched_rt.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 299d012..d7654a3 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -496,10 +496,10 @@ static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
 		struct rq *rq = rq_of_rt_rq(rt_rq);
 
 		spin_lock(&rq->lock);
+		spin_lock(&rt_rq->rt_runtime_lock);
 		if (rt_rq->rt_time) {
 			u64 runtime;
 
-			spin_lock(&rt_rq->rt_runtime_lock);
 			if (rt_rq->rt_throttled)
 				balance_runtime(rt_rq);
 			runtime = rt_rq->rt_runtime;
@@ -510,9 +510,9 @@ static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
 			}
 			if (rt_rq->rt_time || rt_rq->rt_nr_running)
 				idle = 0;
-			spin_unlock(&rt_rq->rt_runtime_lock);
 		} else if (rt_rq->rt_nr_running)
 			idle = 0;
+		spin_unlock(&rt_rq->rt_runtime_lock);
 
 		if (enqueue)
 			sched_rt_rq_enqueue(rt_rq);
-- 
1.6.1.2


  reply	other threads:[~2009-02-05 23:38 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-02-05 23:36 [PATCH 1/2] sched_rt: don't start timer when rt bandwidth disabled Hiroshi Shimamoto
2009-02-05 23:38 ` Hiroshi Shimamoto [this message]
2009-02-05 23:59   ` [PATCH 2/2] sched_rt: protect rt_rq->rt_time by rt_runtime_lock Peter Zijlstra
2009-02-06  0:06     ` Hiroshi Shimamoto
2009-02-06 18:50       ` Hiroshi Shimamoto

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