[PATCH] hrtimer: check hrtimer with a NULL function

Phil Chang
2024-06-05T08:42:06Z

simillar with timers, check for timer->function == NULL.
If the pointer is NULL, discard the request silently.

Signed-off-by: Phil Chang <phil.chang@mediatek.com>
---
kernel/time/hrtimer.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 492c14aac642..72d6e7bc9cd9 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -1297,9 +1297,13 @@ void hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,

base = lock_hrtimer_base(timer, &flags);

+ if (!timer->function)
+ goto out;
+
if (__hrtimer_start_range_ns(timer, tim, delta_ns, mode, base))
hrtimer_reprogram(timer, true);

+out:
unlock_hrtimer_base(timer, &flags);
}
EXPORT_SYMBOL_GPL(hrtimer_start_range_ns);
@@ -1667,6 +1671,11 @@ static void __run_hrtimer(struct hrtimer_cpu_base *cpu_base,
__remove_hrtimer(timer, base, HRTIMER_STATE_INACTIVE, 0);
fn = timer->function;

+ if (WARN_ON_ONCE(!fn)) {
+ /* Should never happen. */
+ goto out;
+ }
+
/*
* Clear the 'is relative' flag for the TIME_LOW_RES case. If the
* timer is restarted with a period then it becomes an absolute
@@ -1710,6 +1719,7 @@ static void __run_hrtimer(struct hrtimer_cpu_base *cpu_base,
* hrtimer_active() cannot observe base->running.timer == NULL &&
* timer->state == INACTIVE.
*/
+out:
raw_write_seqcount_barrier(&base->seq);

WARN_ON_ONCE(base->running != timer);
--
2.18.0