diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 153f8bb0109d..0ea85487446c 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -1779,7 +1779,7 @@ int hrtimers_prepare_cpu(unsigned int cpu)
 
 #ifdef CONFIG_HOTPLUG_CPU
 
-static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
+static int migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
 				struct hrtimer_clock_base *new_base)
 {
 	struct hrtimer *timer;
@@ -1809,15 +1809,19 @@ static void migrate_hrtimer_list(struct hrtimer_clock_base *old_base,
 	}
 #ifdef CONFIG_PREEMPT_RT_BASE
 	list_splice_tail(&old_base->expired, &new_base->expired);
-	if (!list_empty(&new_base->expired))
-		raise_softirq_irqoff(HRTIMER_SOFTIRQ);
+	/*
+	 * Tell the caller to raise HRTIMER_SOFTIRQ.  We can't safely
+	 * acquire ktimersoftd->pi_lock while the base lock is held.
+	 */
+	return !list_empty(&new_base->expired);
 #endif
+	return 0;
 }
 
 int hrtimers_dead_cpu(unsigned int scpu)
 {
 	struct hrtimer_cpu_base *old_base, *new_base;
-	int i;
+	int i, raise = 0;
 
 	BUG_ON(cpu_online(scpu));
 	tick_cancel_sched_timer(scpu);
@@ -1833,13 +1837,16 @@ int hrtimers_dead_cpu(unsigned int scpu)
 	raw_spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
 
 	for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
-		migrate_hrtimer_list(&old_base->clock_base[i],
-				     &new_base->clock_base[i]);
+		raise |= migrate_hrtimer_list(&old_base->clock_base[i],
+					      &new_base->clock_base[i]);
 	}
 
 	raw_spin_unlock(&old_base->lock);
 	raw_spin_unlock(&new_base->lock);
 
+	if (raise)
+		raise_softirq_irqoff(HRTIMER_SOFTIRQ);
+
 	/* Check, if we got expired work to do */
 	__hrtimer_peek_ahead_timers();
 	local_irq_enable();
diff --git a/localversion-rt b/localversion-rt
index 05c35cb58077..6e44e540b927 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt11
+-rt12
