[PATCH v2] hrtimer: check hrtimer with a NULL function

[Phil Chang]

Since hrtimers do not allow a NULL function to be passed,
to prevent a kernel crash, return before adding the timer to a queue.

Signed-off-by: Phil Chang <phil.chang@xxxxxxxxxxxx>
---
 kernel/time/hrtimer.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 492c14aac642..d32c1afe59b3 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -1285,6 +1285,9 @@ void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
 	struct hrtimer_clock_base *base;
 	unsigned long flags;
 
+	if (WARN_ON(!timer->function))
+		return;
+
 	/*
 	 * Check whether the HRTIMER_MODE_SOFT bit and hrtimer.is_soft
 	 * match on CONFIG_PREEMPT_RT = n. With PREEMPT_RT check the hard
-- 
2.18.0