diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index f379943..fd566c1 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -2773,11 +2773,14 @@
 	smp_wmb();
 	cic->key = cfqd_dead_key(cfqd);
 
+	rcu_read_lock();
 	if (rcu_dereference(ioc->ioc_data) == cic) {
+		rcu_read_unlock();
 		spin_lock(&ioc->lock);
 		rcu_assign_pointer(ioc->ioc_data, NULL);
 		spin_unlock(&ioc->lock);
-	}
+	} else
+		rcu_read_unlock();
 
 	if (cic->cfqq[BLK_RW_ASYNC]) {
 		cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]);