1 files changed, 10 insertions, 5 deletions

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index 421be5fe5cc7..ffca825d24bc 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -300,11 +300,10 @@ EXPORT_SYMBOL_GPL(ktime_sub_ns);
  */
 u64 ktime_divns(const ktime_t kt, s64 div)
 {
-        u64 dclc, inc, dns;
+        u64 dclc;
         int sft = 0;
 
-        dclc = dns = ktime_to_ns(kt);
-        inc = div;
+        dclc = ktime_to_ns(kt);
         /* Make sure the divisor is less than 2^32: */
         while (div >> 32) {
                 sft++;
@@ -632,8 +631,6 @@ void clock_was_set(void)
  */
 void hres_timers_resume(void)
 {
-        WARN_ON_ONCE(num_online_cpus() > 1);
-
         /* Retrigger the CPU local events: */
         retrigger_next_event(NULL);
 }
@@ -1003,10 +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;
 }