From da398e77fddf3f935ed88cf16394b05040163cfe Mon Sep 17 00:00:00 2001
From: klayoutmatthias <matthias@klayout.org>
Date: Mon, 25 Jul 2022 22:03:01 +0200
Subject: [PATCH] [Consider merging] avoid a memory corruption issue in
 Netlist::flatten

---
 src/db/db/dbNetlist.cc | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/db/db/dbNetlist.cc b/src/db/db/dbNetlist.cc
index 7f0a04077..3cc519076 100644
--- a/src/db/db/dbNetlist.cc
+++ b/src/db/db/dbNetlist.cc
@@ -505,6 +505,8 @@ void Netlist::flatten_circuit (Circuit *circuit)
 
 void Netlist::flatten ()
 {
+  db::NetlistLocker locker (this);
+
   std::set<db::Circuit *> top_circuits;
   size_t ntop = top_circuit_count ();
   for (db::Netlist::top_down_circuit_iterator tc = begin_top_down (); tc != end_top_down () && ntop > 0; ++tc) {