diff --git a/kernel/sched.c b/kernel/sched.c
index a08387b..f04add9 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1952,6 +1952,7 @@
 	__acquires(rq1->lock)
 	__acquires(rq2->lock)
 {
+	BUG_ON(!irqs_disabled());
 	if (rq1 == rq2) {
 		spin_lock(&rq1->lock);
 		__acquire(rq2->lock);	/* Fake it out ;) */
@@ -1991,6 +1992,11 @@
 	__acquires(busiest->lock)
 	__acquires(this_rq->lock)
 {
+	if (unlikely(!irqs_disabled())) {
+		/* printk() doesn't work good under rq->lock */
+		spin_unlock(&this_rq->lock);
+		BUG_ON(1);
+	}
 	if (unlikely(!spin_trylock(&busiest->lock))) {
 		if (busiest < this_rq) {
 			spin_unlock(&this_rq->lock);
@@ -5067,7 +5073,10 @@
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
-/* Figure out where task on dead CPU should go, use force if neccessary. */
+/*
+ * Figure out where task on dead CPU should go, use force if neccessary.
+ * NOTE: interrupts should be disabled by the caller
+ */
 static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p)
 {
 	unsigned long flags;
@@ -5187,6 +5196,7 @@
 	mmdrop(mm);
 }
 
+/* called under rq->lock with disabled interrupts */
 static void migrate_dead(unsigned int dead_cpu, struct task_struct *p)
 {
 	struct rq *rq = cpu_rq(dead_cpu);
@@ -5203,10 +5213,11 @@
 	 * Drop lock around migration; if someone else moves it,
 	 * that's OK.  No task can be added to this CPU, so iteration is
 	 * fine.
+	 * NOTE: interrupts should be left disabled  --dev@
 	 */
-	spin_unlock_irq(&rq->lock);
+	spin_unlock(&rq->lock);
 	move_task_off_dead_cpu(dead_cpu, p);
-	spin_lock_irq(&rq->lock);
+	spin_lock(&rq->lock);
 
 	put_task_struct(p);
 }