[PATCH -tip] sched: more sched_domain iterations fix

[Xiaotian Feng <dfeng@redhat.com>]

sched_domain iterations needs to be protected by rcu_read_lock() now,
this patch adds another two places which needs the rcu lock.

Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
---
 kernel/sched_rt.c    |    2 ++
 kernel/sched_stats.h |    2 ++
 2 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 19ecb31..901ed2a 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -1282,7 +1282,9 @@ static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
 	int cpu;
 
 	for (tries = 0; tries < RT_MAX_TRIES; tries++) {
+		rcu_read_lock();
 		cpu = find_lowest_rq(task);
+		rcu_read_unlock();
 
 		if ((cpu == -1) || (cpu == rq->cpu))
 			break;
diff --git a/kernel/sched_stats.h b/kernel/sched_stats.h
index 48ddf43..d25c8c1 100644
--- a/kernel/sched_stats.h
+++ b/kernel/sched_stats.h
@@ -38,6 +38,7 @@ static int show_schedstat(struct seq_file *seq, void *v)
 #ifdef CONFIG_SMP
 		/* domain-specific stats */
 		preempt_disable();
+		rcu_read_lock();
 		for_each_domain(cpu, sd) {
 			enum cpu_idle_type itype;
 
@@ -64,6 +65,7 @@ static int show_schedstat(struct seq_file *seq, void *v)
 			    sd->ttwu_wake_remote, sd->ttwu_move_affine,
 			    sd->ttwu_move_balance);
 		}
+		rcu_read_unlock();
 		preempt_enable();
 #endif
 	}
-- 
1.7.1