FFI in Miri at 8000 segfaults per second (Nia Deckers at RustWeek)

Nia Deckers explains how Miri was extended to support arbitrary foreign function interfaces while still detecting undefined behavior.

FFI in Miri at 8000 segfaults per second by Nia Deckers. Miri is an essential tool for checking unsafe Rust code, but it had always been limited to running that code and no more. Work has been done over the past years to make it possible to perform arbitrary FFI from within it while still detecting almost all UB, enabling more and more real-world code to be validated. Doing so required writing most of a debugger inside Miri, pulling in a disassembler, and making very liberal use of unix signals. About Nia Espera (she/her): Compiler Engineer - git: github.com/nia-e - bluesky: bsky.app/profile/nia.is.fckn.gay - linkedin: linkedin.com/in/nia-esp This talk was given at RustWeek 2026 as part of the Rust Project track on Wednesday 20 May. You can find a playlist of all talks in this track at youtube.com/playlist?list=PL8Q1w7Ff68DBkk0ddSEqdf97swuDvMSKS, and a playlist of all RustWeek 2026 talks at youtube.com/playlist?list=PL8Q1w7Ff68DBpmF38rcIAf8Z9Gj2TnlgM For information about RustWeek 2027, go to 2027.rustweek.org. We hope to see you there!