---
-title: "The Tale of a Bug in Arc: Sychronization and Data Races"
+title: "The Tale of a Bug in Arc: Synchronization and Data Races"
categories: rust research
+reddit: https://www.reddit.com/r/rust/comments/8ykuhv/the_tale_of_a_bug_in_arc_synchronization_and_data/
---
While I was busy doing Rust-unelated research, [RustBelt](https://plv.mpi-sws.org/rustbelt/) continues to move and recently found another bug (after [a missing `impl !Sync` that we found previously]({{ site.baseurl }}{% post_url 2017-06-09-mutexguard-sync %})): It turns out that `Arc::get_mut` did [not perform sufficient synchronization](https://github.com/rust-lang/rust/issues/51780), leading to a data race.