1 files changed, 8 insertions, 9 deletions
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 9af1d6a8095..ab80515008f 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -154,15 +154,6 @@ static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
 }
 
 /*
- * Helper function to check, whether the timer is running the callback
- * function
- */
-static inline int hrtimer_callback_running(struct hrtimer *timer)
-{
-	return timer->state & HRTIMER_STATE_CALLBACK;
-}
-
-/*
  * Functions and macros which are different for UP/SMP systems are kept in a
  * single place
  */
@@ -1012,10 +1003,18 @@ hrtimer_start(struct hrtimer *timer, ktime_t tim, const enum hrtimer_mode mode)
 	 */
 	raise = timer->state == HRTIMER_STATE_PENDING;
 
+	/*
+	 * We use preempt_disable to prevent this task from migrating after
+	 * setting up the softirq and raising it. Otherwise, if me migrate
+	 * we will raise the softirq on the wrong CPU.
+	 */
+	preempt_disable();
+
 	unlock_hrtimer_base(timer, &flags);
 
 	if (raise)
 		hrtimer_raise_softirq();
+	preempt_enable();
 
 	return ret;
 }