diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index f26da2b..4611c84 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1501,8 +1501,11 @@ cfq_cic_lookup(struct cfq_data *cfqd, struct io_context *ioc)
 	 * we maintain a last-hit cache, to avoid browsing over the tree
 	 */
 	cic = rcu_dereference(ioc->ioc_data);
-	if (cic && cic->key == cfqd)
+	if (cic && cic->key == cfqd) {
+		/* check if cic belongs to ioc */
+		BUG_ON(cic->ioc != ioc);
 		return cic;
+	}
 
 	do {
 		rcu_read_lock();