block/blk-mq.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index ddc2eed64771..4f575de7fdd0 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -521,6 +521,8 @@ void blk_mq_add_to_requeue_list(struct request *rq, bool at_head)
 	 */
 	BUG_ON(rq->cmd_flags & REQ_SOFTBARRIER);
 
+WARN_ON_ONCE(!list_empty(&rq->queuelist));
+
 	spin_lock_irqsave(&q->requeue_lock, flags);
 	if (at_head) {
 		rq->cmd_flags |= REQ_SOFTBARRIER;
@@ -838,6 +840,7 @@ static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx)
 			queued++;
 			break;
 		case BLK_MQ_RQ_QUEUE_BUSY:
+WARN_ON_ONCE(!list_empty(&rq->queuelist));
 			list_add(&rq->queuelist, &rq_list);
 			__blk_mq_requeue_request(rq);
 			break;
@@ -1034,6 +1037,8 @@ static inline void __blk_mq_insert_req_list(struct blk_mq_hw_ctx *hctx,
 
 	trace_block_rq_insert(hctx->queue, rq);
 
+WARN_ON_ONCE(!list_empty(&rq->queuelist));
+
 	if (at_head)
 		list_add(&rq->queuelist, &ctx->rq_list);
 	else
@@ -1137,6 +1142,7 @@ void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
 			depth = 0;
 		}
 
+WARN_ON_ONCE(!list_empty(&rq->queuelist));
 		depth++;
 		list_add_tail(&rq->queuelist, &ctx_list);
 	}
@@ -1172,6 +1178,7 @@ static inline bool blk_mq_merge_queue_io(struct blk_mq_hw_ctx *hctx,
 		blk_mq_bio_to_request(rq, bio);
 		spin_lock(&ctx->lock);
 insert_rq:
+WARN_ON_ONCE(rq->mq_ctx != ctx);
 		__blk_mq_insert_request(hctx, rq, false);
 		spin_unlock(&ctx->lock);
 		return false;
@@ -1326,6 +1333,7 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
 				old_rq = same_queue_rq;
 				list_del_init(&old_rq->queuelist);
 			}
+WARN_ON_ONCE(!list_empty(&rq->queuelist));
 			list_add_tail(&rq->queuelist, &plug->mq_list);
 		} else /* is_sync */
 			old_rq = rq;
@@ -1412,6 +1420,7 @@ static blk_qc_t blk_sq_make_request(struct request_queue *q, struct bio *bio)
 			trace_block_plug(q);
 		}
 
+WARN_ON_ONCE(!list_empty(&rq->queuelist));
 		list_add_tail(&rq->queuelist, &plug->mq_list);
 		return cookie;
 	}