Rustup 1.29.3 fixes an illegal-instruction crash on x86_64 CPUs without SSE4.1
Serguey Asael Shinder1 min readThe Rustup team has published rustup 1.29.3, a point release that fixes two regressions from the previous version. The first is an "Illegal instruction" error on certain x86_64 CPUs that lack SSE4.1 (pull request 5162). The second is a "lock() not supported" error on Solaris (pull request 5167).
Updating follows the usual route: stop any programs that may be using rustup, such as an open IDE, and run rustup self update. Rustup also updates itself at the end of a normal rustup update. For this release the team adds manual steps for anyone whose self-update fails: download the matching rustup-init binary, make sure no other rustup processes are running, and replace the existing binary, usually $HOME/.cargo/bin/rustup or $CARGO_HOME/bin/rustup, with the downloaded file renamed to rustup.
The team repeats its standing caveat that anti-malware scanners may block a new rustup release or stop it from creating files, especially when installing rust-docs with its many small files, and that this usually resolves itself within a few weeks.
What it means
The x86_64 fix matters for older or low-end machines and some CI runners: a toolchain manager that crashes on start is a hard stop for everything that builds Rust there. If a self-update fails on such a machine, the manual binary swap is the documented way out.