IIUC Rust stack overflows are actually checked, hit a guard page, and unwind the stack https://github.com/rust-lang/compiler-builtins/blob/master/src/probestack

IIUC Rust stack overflows are actually checked, hit a guard page, and unwind the stack https://github.com/rust-lang/compiler-builtins/blob/master/src/probestack.rs https://github.com/rust-lang/compiler-builtins/blob/master/s... A cactusref is owned by a single thread so there's no STW issue, but you also can't share them mutably between threads like structures available in some GCed languages.