Index: main/astobj2.c
===================================================================
--- main/astobj2.c	(revision 417247)
+++ main/astobj2.c	(working copy)
@@ -499,14 +499,8 @@
 {
 	struct astobj2 *obj = INTERNAL_OBJ(user_data);
 
-	if (obj == NULL) {
-		ast_log_backtrace();
-		ast_assert(0);
-		return -1;
-	}
-
-	if (ref_log) {
-		if (obj->priv_data.ref_counter + delta == 0) {
+	if (ref_log && user_data) {
+		if (obj && obj->priv_data.ref_counter + delta == 0) {
 			fprintf(ref_log, "%p,%d,%d,%s,%d,%s,**destructor**,%s\n", user_data, delta, ast_get_tid(), file, line, func, tag);
 			fflush(ref_log);
 		} else if (delta != 0) {
@@ -515,6 +509,13 @@
 			fflush(ref_log);
 		}
 	}
+
+	if (obj == NULL) {
+		ast_log_backtrace();
+		ast_assert(0);
+		return -1;
+	}
+
 	return internal_ao2_ref(user_data, delta, file, line, func);
 }