Merge commit '900cfa46191a7d87cf1891924cb90499287fd235'; branches 'timers/nohz',...

[~andy/linux] / kernel / hrtimer.c

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 635739d219daa4a74d2249e11cc142c559295578..ffca825d24bc1db3f3810db01285bf5f08f50786 100644 (file)
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -1000,10 +1000,18 @@ 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;
 }