duration of stay after filing L2 extension

[IworkonH1]

Hi,

 

I need your advice on my current situation.

 

My child (on L2) I-94 has expired in Jan 2016 and I had filed Form i539 before I-94 expiry for extension. It has been almost 6 months of filing but there is no response from USCIS. My stay is valid and authorized. I am worried for his stay. Is there any kind of limit of his stay after I-94 expiry irrespective of I-94 extension filing ? 

 

If there is limit of L2 stay after I-94 expiry ( even though extension is filed), what I can do now to make his stay problem free.

 

Please advice.

 

Thanks