diff --git a/ext/session/session.c b/ext/session/session.c
index ffb6fb381bb..f4317f5ebfb 100644
--- a/ext/session/session.c
+++ b/ext/session/session.c
@@ -96,6 +96,7 @@ static inline void php_rinit_session_globals(TSRMLS_D) /* {{{ */
 	PS(session_status) = php_session_none;
 	PS(mod_data) = NULL;
 	PS(mod_user_is_open) = 0;
+	PS(defined_sid) = 1;
 	/* Do NOT init PS(mod_user_names) here! */
 	PS(http_session_vars) = NULL;
 }