[PATCH 2/2] sched_rt: protect rt_rq->rt_time by rt_runtime_lock

[Hiroshi Shimamoto]

From: Hiroshi Shimamoto <h-shimamoto@xxxxxxxxxxxxx>

Impact: fix possible race condition

rt_rq->rt_time should be protected.

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@xxxxxxxxxxxxx>
---
 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

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