diff --git a/gunicorn/ctl/server.py b/gunicorn/ctl/server.py
index 8b32a5ab..0fd24ee3 100644
--- a/gunicorn/ctl/server.py
+++ b/gunicorn/ctl/server.py
@@ -31,15 +31,14 @@ from gunicorn.ctl.protocol import (
 # Module-level tracking of active control server instances for fork handling.
 # This is necessary because os.register_at_fork() callbacks are process-level.
 _active_servers = set()
-_fork_handlers_registered = False
+_module_state = {"fork_handlers_registered": False}
 
 
 def _register_fork_handlers():
     """Register fork handlers once at module level."""
-    global _fork_handlers_registered
-    if _fork_handlers_registered:
+    if _module_state["fork_handlers_registered"]:
         return
-    _fork_handlers_registered = True
+    _module_state["fork_handlers_registered"] = True
 
     os.register_at_fork(
         before=_before_fork,
diff --git a/gunicorn/workers/gtornado.py b/gunicorn/workers/gtornado.py
index 2c4b5c58..fc75fc2d 100644
--- a/gunicorn/workers/gtornado.py
+++ b/gunicorn/workers/gtornado.py
@@ -98,10 +98,12 @@ class TornadoWorker(Worker):
                 not isinstance(app, tornado.web.Application):
             app = WSGIContainer(app)
 
+        worker = self
+
         class _HTTPServer(tornado.httpserver.HTTPServer):
 
-            def on_close(instance, server_conn):
-                self.handle_request()
+            def on_close(self, server_conn):
+                worker.handle_request()
                 super().on_close(server_conn)
 
         if self.cfg.is_ssl: