diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index 0319d63..0c62144 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -2713,6 +2713,28 @@ static void bfq_bfqq_save_state(struct bfq_queue *bfqq)
 	}
 }
 
+
+static
+void bfq_release_process_ref(struct bfq_data *bfqd, struct bfq_queue *bfqq)
+{
+	/*
+	 * To prevent bfqq's service guarantees from being violated,
+	 * bfqq may be left busy, i.e., queued for service, even if
+	 * empty (see comments in __bfq_bfqq_expire() for
+	 * details). But, if no process will send requests to bfqq any
+	 * longer, then there is no point in keeping bfqq queued for
+	 * service. In addition, keeping bfqq queued for service, but
+	 * with no process ref any longer, may have caused bfqq to be
+	 * freed when dequeued from service. But this is assumed to
+	 * never happen.
+	 */
+	if (bfq_bfqq_busy(bfqq) && RB_EMPTY_ROOT(&bfqq->sort_list) &&
+	    bfqq != bfqd->in_service_queue)
+		bfq_del_bfqq_busy(bfqd, bfqq, false);
+
+	bfq_put_queue(bfqq);
+}
+
 static void
 bfq_merge_bfqqs(struct bfq_data *bfqd, struct bfq_io_cq *bic,
 		struct bfq_queue *bfqq, struct bfq_queue *new_bfqq)
@@ -2783,8 +2805,7 @@ bfq_merge_bfqqs(struct bfq_data *bfqd, struct bfq_io_cq *bic,
 	 */
 	new_bfqq->pid = -1;
 	bfqq->bic = NULL;
-	/* release process reference to bfqq */
-	bfq_put_queue(bfqq);
+	bfq_release_process_ref(bfqd, bfqq);
 }
 
 static bool bfq_allow_bio_merge(struct request_queue *q, struct request *rq,
@@ -4899,7 +4920,7 @@ static void bfq_exit_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq)
 
 	bfq_put_cooperator(bfqq);
 
-	bfq_put_queue(bfqq); /* release process reference */
+	bfq_release_process_ref(bfqd, bfqq);
 }
 
 static void bfq_exit_icq_bfqq(struct bfq_io_cq *bic, bool is_sync)
@@ -5001,8 +5022,7 @@ static void bfq_check_ioprio_change(struct bfq_io_cq *bic, struct bio *bio)
 
 	bfqq = bic_to_bfqq(bic, false);
 	if (bfqq) {
-		/* release process reference on this queue */
-		bfq_put_queue(bfqq);
+		bfq_release_process_ref(bfqd, bfqq);
 		bfqq = bfq_get_queue(bfqd, bio, BLK_RW_ASYNC, bic);
 		bic_set_bfqq(bic, bfqq, false);
 	}
@@ -5963,7 +5983,7 @@ bfq_split_bfqq(struct bfq_io_cq *bic, struct bfq_queue *bfqq)
 
 	bfq_put_cooperator(bfqq);
 
-	bfq_put_queue(bfqq);
+	bfq_release_process_ref(bfqq->bfqd, bfqq);
 	return NULL;
 }