错误：会话回调期望在YII中使用HHVM返回true / false

I am testing my existing application with HHVM and it is working fine but i got some error on Session section. Here i have attached Session error

Session callback expects true/false return value (/var/www/yii/framework/web/CHttpSession.php:181)

Versions: HHVM - 3.5.0 (rel) Yii - 1.1.14

And i am using redis to store the session. Can you anybody suggest me how to fix this issue?

Thank you...