diff --git a/line-log.c b/line-log.c
index 68eeb425f8a..75c8b1acfff 100644
--- a/line-log.c
+++ b/line-log.c
@@ -481,7 +481,7 @@ static struct commit *check_single_commit(struct rev_info *revs)
 		if (obj->flags & UNINTERESTING)
 			continue;
 		obj = deref_tag(revs->repo, obj, NULL, 0);
-		if (obj->type != OBJ_COMMIT)
+		if (!obj || obj->type != OBJ_COMMIT)
 			die("Non commit %s?", revs->pending.objects[i].name);
 		if (commit)
 			die("More than one commit to dig from: %s and %s?",