diff --git a/[refs] b/[refs]
index ee03d3d9f218..f498cd5d62d7 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: fbbf055692aeb25c54c49d9ca84532de836fbba0
+refs/heads/master: c10b61f0910466b4b99c266a7d76ac4390743fb5
diff --git a/trunk/block/cfq-iosched.c b/trunk/block/cfq-iosched.c
index 5ff4f4850e71..153f6277e5c8 100644
--- a/trunk/block/cfq-iosched.c
+++ b/trunk/block/cfq-iosched.c
@@ -1986,6 +1986,15 @@ static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq)
 	int process_refs, new_process_refs;
 	struct cfq_queue *__cfqq;
 
+	/*
+	 * If there are no process references on the new_cfqq, then it is
+	 * unsafe to follow the ->new_cfqq chain as other cfqq's in the
+	 * chain may have dropped their last reference (not just their
+	 * last process reference).
+	 */
+	if (!cfqq_process_refs(new_cfqq))
+		return;
+
 	/* Avoid a circular list and skip interim queue merges */
 	while ((__cfqq = new_cfqq->new_cfqq)) {
 		if (__cfqq == cfqq)
@@ -1994,17 +2003,17 @@ static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq)
 	}
 
 	process_refs = cfqq_process_refs(cfqq);
+	new_process_refs = cfqq_process_refs(new_cfqq);
 	/*
 	 * If the process for the cfqq has gone away, there is no
 	 * sense in merging the queues.
 	 */
-	if (process_refs == 0)
+	if (process_refs == 0 || new_process_refs == 0)
 		return;
 
 	/*
 	 * Merge in the direction of the lesser amount of work.
 	 */
-	new_process_refs = cfqq_process_refs(new_cfqq);
 	if (new_process_refs >= process_refs) {
 		cfqq->new_cfqq = new_cfqq;
 		atomic_add(process_refs, &new_cfqq->ref);