sched: Fix pick_next_highest_task_rt() for cgroups

Upstream commit: 3d07467b7aa91623b31d7b5888a123a2c8c8e9cc

Since pick_next_highest_task_rt() already iterates all the cgroups and
is really only interested in tasks, skip over the !task entries.

Reported-by: Dhaval Giani <dhaval.giani@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: Dhaval Giani <dhaval.giani@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 6 insertions, 1 deletions

diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 9de5f18b92bf..6a0029a18259 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -1207,7 +1207,12 @@ static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu)
                 if (next && next->prio < idx)
                         continue;
                 list_for_each_entry(rt_se, array->queue + idx, run_list) {
-                        struct task_struct *p = rt_task_of(rt_se);
+                        struct task_struct *p;
+
+                        if (!rt_entity_is_task(rt_se))
+                                continue;
+
+                        p = rt_task_of(rt_se);
                         if (pick_rt_task(rq, p, cpu)) {
                                 next = p;
                                 break;