From eae39b339ca3ba5e0271f353927cd02a433fe66b Mon Sep 17 00:00:00 2001
From: rdb <git@rdb.name>
Date: Tue, 15 Apr 2025 10:44:33 +0200
Subject: [PATCH] collide: Fix CollisionNode owner crash (grab GIL when
 destructing)

---
 panda/src/collide/collisionNode_ext.cxx | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/panda/src/collide/collisionNode_ext.cxx b/panda/src/collide/collisionNode_ext.cxx
index 8508cf5206..62e7d5f874 100644
--- a/panda/src/collide/collisionNode_ext.cxx
+++ b/panda/src/collide/collisionNode_ext.cxx
@@ -53,7 +53,17 @@ void Extension<CollisionNode>::
 set_owner(PyObject *owner) {
   if (owner != Py_None) {
     PyObject *ref = PyWeakref_NewRef(owner, nullptr);
-    _this->set_owner(ref, [](void *obj) { Py_DECREF((PyObject *)obj); });
+    _this->set_owner(ref, [](void *obj) {
+#if defined(HAVE_THREADS) && !defined(SIMPLE_THREADS)
+      // Use PyGILState to protect this asynchronous call.
+      PyGILState_STATE gstate;
+      gstate = PyGILState_Ensure();
+#endif
+      Py_DECREF((PyObject *)obj);
+#if defined(HAVE_THREADS) && !defined(SIMPLE_THREADS)
+      PyGILState_Release(gstate);
+#endif
+    });
   } else {
     _this->clear_owner();
   }