It's actually the hardware that enforces such guarantees. The OS could have bugs, like the WASM program - even if the entire stack is written in Rust from top t

It's actually the hardware that enforces such guarantees. The OS could have bugs, like the WASM program - even if the entire stack is written in Rust from top to bottom. Really the only solution is memory safe hardware, which there is effort going into, e.g. ARM CHERI[0] and ARM MTE [0] https://msrc.microsoft.com/blog/2022/01/an_armful_of_cheris/ https://msrc.microsoft.com/blog/2022/01/an_armful_of_cheris/