He doesn't. Linus uses MicroEMACS [0], which is an entirely different editor that uses emacs bindings.

It's not the lisp vm that incidentally happens to edit code that GNU Emacs is.

Or, as he puts it [1]:

> I use this abomination called "micro-emacs", which has absolutely nothing to do with GNU emacs except that some of the key bindings are similar.

[0]: https://github.com/torvalds/uemacs [1]: https://www.tag1consulting.com/blog/interview-linus-torvalds...