The stack for any thread other than the first is just memory like any other allocation. You can free it, resize it, copy it elsewhere, whatever you want to do.

The stack for any thread other than the first is just memory like any other allocation. You can free it, resize it, copy it elsewhere, whatever you want to do. Literally just a pointer in a register. People work up weird mythologies about it, but the stack can be anything you want if you're willing to write code to manage it.