diff --git a/block/blk-core.c b/block/blk-core.c
index eea246567884bc..473dd698effdb8 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1753,8 +1753,11 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio)
 		/*
 		 * If this is the first request added after a plug, fire
 		 * of a plug trace.
+		 *
+		 * @request_count may become stale because of schedule
+		 * out, so check plug list again.
 		 */
-		if (!request_count)
+		if (!request_count || list_empty(&plug->list))
 			trace_block_plug(q);
 		else {
 			struct request *last = list_entry_rq(plug->list.prev);
diff --git a/block/blk-mq.c b/block/blk-mq.c
index ae8df5ec20d386..f39e69c732cc62 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1497,6 +1497,13 @@ static blk_qc_t blk_sq_make_request(struct request_queue *q, struct bio *bio)
 		struct request *last = NULL;
 
 		blk_mq_bio_to_request(rq, bio);
+
+		/*
+		 * @request_count may become stale because of schedule
+		 * out, so check the list again.
+		 */
+		if (list_empty(&plug->mq_list))
+			request_count = 0;
 		if (!request_count)
 			trace_block_plug(q);
 		else