Merge branch 'linus' into tracing/mmiotrace

1 files changed, 8 insertions, 0 deletions

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 421be5fe5cc7..ab80515008f4 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -1003,10 +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;
 }