mixing passive and active voice in same sentence

Hello,
I wrote this question before but think it got erased.

Is there some grammar rule that says you cannot mix active and passive voice in the SAME sentence?

John waited for six hours and was told that he needed to wait 10 more hours.

I know that this can be written complete active OR passive voice (and someone told him that he needed to...),
but I want to know if there is a rule on mixing active and passive voice in the same sentence...

Thanks.