J-1, Canadain,and Waiver?

Hello,

I used to hold a J-1 in USA, then immigrated to Canada and became a Canadian citizen. Now I am working in US with H1-B, having the intention to apply for US green card. I heard I still need the Chinese government to provide a waiver for my old J-1 visa, but not sure it is true or not.

If anyone has similar expereince or has the knowledge, please be generous, your input is highly appreciated.