diff --git a/[refs] b/[refs]
index dbf90d34e4c3..108d4200b256 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 640eb3b0456f8273726d31160aa24568ae703eec
+refs/heads/master: 233886dd32ad71daf9c21bf3728c0933a94870f0
diff --git a/trunk/drivers/md/dm-bio-list.h b/trunk/drivers/md/dm-bio-list.h
index bc021e1fd4d1..bbf4615f0e30 100644
--- a/trunk/drivers/md/dm-bio-list.h
+++ b/trunk/drivers/md/dm-bio-list.h
@@ -33,6 +33,9 @@ static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
 
 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
 {
+	if (!bl2->head)
+		return;
+
 	if (bl->tail)
 		bl->tail->bi_next = bl2->head;
 	else