[PATCH] genirq/timings: prevent potential array overflow in __irq_timings_store()

[Ben Dai]

From: Ben Dai <ben.dai@xxxxxxxxxx>

When the interrupt interval is greater than 2 ^ PREDICTION_BUFFER_SIZE *
PREDICTION_FACTOR us and less than 1s, the calculated index will be greater
than the length of irqs->ema_time[]. Check the calculated index before
using it to prevent array overflow.

Signed-off-by: Ben Dai <ben.dai@xxxxxxxxxx>
---
 kernel/irq/timings.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/kernel/irq/timings.c b/kernel/irq/timings.c
index 773b6105c4ae..6990490fa67b 100644
--- a/kernel/irq/timings.c
+++ b/kernel/irq/timings.c
@@ -453,6 +453,11 @@ static __always_inline void __irq_timings_store(int irq, struct irqt_stat *irqs,
 	 */
 	index = irq_timings_interval_index(interval);
 
+	if (index > PREDICTION_BUFFER_SIZE - 1) {
+		irqs->count = 0;
+		return;
+	}
+
 	/*
 	 * Store the index as an element of the pattern in another
 	 * circular array.
-- 
2.25.1