diff --git a/commit-graph.c b/commit-graph.c
index 3860a0d847..0998445515 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -713,6 +713,7 @@ static void close_commit_graph_one(struct commit_graph *g)
 	if (!g)
 		return;
 
+	clear_commit_graph_data_slab(&commit_graph_data_slab);
 	close_commit_graph_one(g->base_graph);
 	free_commit_graph(g);
 }