Commit ("it always worked, just refactored it to make it nicer, for fun"): https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/lin...

Article: https://www.phoronix.com/news/Linux-65-User-Mode-Stack-Expan...

Followup (it wasn't really only "for fun"): https://www.phoronix.com/news/Linux-StackRot