[PATCH 2/2] sched/deadline: Don't return invalid cpu in cpudl_maximum_cpu()

[Byungchul Park]

When the heap tree is empty, cp->elements[0].cpu has meaningless value.
We need to consider the case.

Signed-off-by: Byungchul Park <byungchul.park@xxxxxxx>
---
 kernel/sched/cpudeadline.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
index d4a6963..9b314a9 100644
--- a/kernel/sched/cpudeadline.c
+++ b/kernel/sched/cpudeadline.c
@@ -110,7 +110,8 @@ static void cpudl_heapify(struct cpudl *cp, int idx)
 
 static inline int cpudl_maximum_cpu(struct cpudl *cp)
 {
-	return cp->elements[0].cpu;
+	int cpu = cp->elements[0].cpu;
+	return cp->elements[cpu].idx == IDX_INVALID ? -1 : cpu;
 }
 
 static inline u64 cpudl_maximum_dl(struct cpudl *cp)
-- 
1.9.1