Charles Oakley says he still has Anthony Mason's back -- and he's going in on Fat Joe for "disrespecting" the NY Knicks legend by naming him as the mystery victim in a Biggie Smalls track.
"You don't talk about a guy after he's deceased," Oakley said ... "definitely disrespectful."
The song in question is Biggie's "I Got a Story to Tell" -- in which the rapper details a night where he was sleeping with the GF of a Knicks player ... and when the player came home, Biggie posed as a burglar and pulled out a gun to rob him to cover up the affair.