What is the punishment for possession of controlled substance in Texas jail?

It's a 3rd degree felony under Penal Code § 38.11 and carries a penalty of 2 to 10 years imprisonment and a possible fine up to $10,000. That's in addition to the penalty for the mere possession of the controlled substance, which depends on the substance and the amount. It kind of smacks of double jeopardy but as the saying goes, "Don't do the crime if you can't do the time."