diff --git a/gunicorn/sock.py b/gunicorn/sock.py
index fdb5ae752..fe5750672 100644
--- a/gunicorn/sock.py
+++ b/gunicorn/sock.py
@@ -54,11 +54,15 @@ def bind(self, sock):
         sock.bind(self.cfg_addr)
 
     def close(self):
+        if self.sock is None:
+            return
+
         try:
             self.sock.close()
         except socket.error as e:
             self.log.info("Error while closing socket %s", str(e))
-        del self.sock
+
+        self.sock = None
 
 
 class TCPSocket(BaseSocket):