--- asterisk-11.0.1-orig/channels/chan_sip.c	2012-11-05 16:29:46.000000000 +0000
+++ asterisk-11.0.1/channels/chan_sip.c	2012-11-21 03:46:37.948354209 +0000
@@ -14145,6 +14145,8 @@ static void state_notify_build_xml(struc
 
 					ast_channel_unlock(callee);
 					callee = ast_channel_unref(callee);
+				} else {
+					break;
 				}
 
 				/* We create a fake call-id which the phone will send back in an INVITE