diff --git a/runbot_merge/controllers/__init__.py b/runbot_merge/controllers/__init__.py
index c8c71811..05e89b66 100644
--- a/runbot_merge/controllers/__init__.py
+++ b/runbot_merge/controllers/__init__.py
@@ -174,6 +174,7 @@ def handle_pr(env, event):
         FOR UPDATE SKIP LOCKED;
         ''', [pr_obj.id])
         res = env.cr.fetchone()
+        # FIXME: store some sort of "try to close it later" if the merge fails?
         if not res:
             return 'Ignored: could not lock rows (probably being merged)'
 
diff --git a/runbot_merge/models/pull_requests.py b/runbot_merge/models/pull_requests.py
index b7907422..0ceaaf56 100644
--- a/runbot_merge/models/pull_requests.py
+++ b/runbot_merge/models/pull_requests.py
@@ -1231,6 +1231,11 @@ class Stagings(models.Model):
             gh = {repo.name: repo.github() for repo in project.repo_ids}
             repo_name = None
             staging_heads = json.loads(self.heads)
+            self.env.cr.execute('''
+            SELECT 1 FROM runbot_merge_pull_requests
+            WHERE id in %s
+            FOR UPDATE
+            ''', [tuple(self.mapped('batch_ids.prs.id'))])
             try:
                 repo_name = self._safety_dance(gh, staging_heads)
             except exceptions.FastForwardError as e: