[PATCH] clocksource: atmel-st: Variable sr in at91rm9200_timer_interrupt() could be uninitialized

[Yizhuo]

Inside function at91rm9200_timer_interrupt(), variable sr could
be uninitialized if regmap_read() fails. However, sr is used
to decide the control flow later in the if statement, which is
potentially unsafe. We could check the return value of
regmap_read() and print an error here.

Signed-off-by: Yizhuo <yzhai003@xxxxxxx>
---
 drivers/clocksource/timer-atmel-st.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/clocksource/timer-atmel-st.c b/drivers/clocksource/timer-atmel-st.c
index ab0aabfae5f0..061a3f27847e 100644
--- a/drivers/clocksource/timer-atmel-st.c
+++ b/drivers/clocksource/timer-atmel-st.c
@@ -48,8 +48,14 @@ static inline unsigned long read_CRTR(void)
 static irqreturn_t at91rm9200_timer_interrupt(int irq, void *dev_id)
 {
 	u32 sr;
+	int ret;
+
+	ret = regmap_read(regmap_st, AT91_ST_SR, &sr);
+	if (ret) {
+		pr_err("Fail to read AT91_ST_SR.\n");
+		return ret;
+	}
 
-	regmap_read(regmap_st, AT91_ST_SR, &sr);
 	sr &= irqmask;
 
 	/*
-- 
2.17.1