Rust used guard pages, but was still vulnerable to attacks based on jumping over the guard page, which is the same issue that Stack Clash exploited in C program

Rust used guard pages, but was still vulnerable to attacks based on jumping over the guard page, which is the same issue that Stack Clash exploited in C programs. The ideal fix for that is stack probing, which Rust is indeed moving towards. However, in the past, Rust had a different fix: it would add a bit to all function prologues that explicitly checked for running out of stack space - based on LLVM split stack support, and a remnant of when (even further in the past) Rust actually used split stacks. The explicit check also protected against jumping over the guard page, but was much more expensive than stack probing, and also caused issues with embedded use cases. The plan was to replace it with stack probing, but things dragged on and it was removed before the replacement was ready.