diff --git a/block/blk-map.c b/block/blk-map.c
index 955d75c..bc5ce60 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -143,6 +143,7 @@
 	return 0;
 unmap_rq:
 	blk_rq_unmap_user(bio);
+	rq->bio = NULL;
 	return ret;
 }
 EXPORT_SYMBOL(blk_rq_map_user);