diff --git a/data/model/legacy.py b/data/model/legacy.py
index 94f799992..85b533053 100644
--- a/data/model/legacy.py
+++ b/data/model/legacy.py
@@ -1803,7 +1803,7 @@ def create_or_update_tag(namespace_name, repository_name, tag_name,
       query = _tag_alive(RepositoryTag
                          .select()
                          .where(RepositoryTag.repository == repo, RepositoryTag.name == tag_name))
-      tag = query.get()
+      tag = db_for_update(query).get()
       tag.lifetime_end_ts = now_ts
       tag.save()
     except RepositoryTag.DoesNotExist: