The Linux kernel is increasingly adopting Rust as its primary language for new development, moving away from its long-standing reliance on C. This shift, championed by stable kernel maintainer Greg Kroah-Hartman, is driven by Rust's enhanced memory safety features and its ability to streamline the development process, making coding more enjoyable and secure. While C will continue to be part of the kernel, Rust is poised to become the default for critical new subsystems and drivers, reflecting a strategic move towards improved code reliability and reduced vulnerability.
Rust: A new era for Linux development
Linux stable kernel maintainer Greg Kroah-Hartman has become a strong advocate for Rust, citing its ability to make programming enjoyable and its inherent safety features. He noted that Rust's ownership and type systems significantly reduce the "stupid little tiny things" that often lead to kernel vulnerabilities, such as unchecked pointers and memory leaks. This makes Rust a valuable asset for overstretched maintainers who can now focus on complex logic bugs rather than trivial errors. Kroah-Hartman's assertion that 80% of kernel CVEs could be eliminated by Rust underscores its potential to enhance code reliability and reduce the review workload.
Kroah-Hartman, who oversees the Linux kernel CVE process, highlighted that the kernel addresses around 13 vulnerabilities daily, with most stemming from simple C-related mistakes. Rust's compile-time error detection frees maintainers from tedious debugging, allowing them to concentrate on higher-level issues. This has led to Rust becoming the default language for new development in critical subsystems, with some new drivers for graphic subsystems and Android's Binder IPC mechanism being exclusively accepted in Rust. The Linux community has officially endorsed this transition, recognizing Rust as a permanent and essential part of the kernel's future.
Boosting security and streamlining maintenance
The adoption of Rust is reshaping how C code is written in the kernel, as maintainers are revisiting existing APIs to incorporate Rust-like safety mechanisms, such as guard and scoped-allocation. This influence has already made C code more reliable and secure, demonstrating Rust's positive impact beyond its direct implementation. The emphasis on Rust stems from its ability to enforce locking and lifetime rules during compilation, which simplifies the review process for maintainers. This allows them to allocate their limited time to critical logic validation rather than routine error checking.
While Rust will not lead to a complete rewrite of the Linux kernel, it is becoming the preferred language for new modules and drivers within key subsystems. This strategic shift ensures that new development benefits from Rust's enhanced safety features, gradually improving the overall security posture of the kernel. Kroah-Hartman acknowledges the challenge of transitioning a community long entrenched in C, but he emphasizes that Rust's ability to reduce worry over common programming pitfalls makes coding more enjoyable and efficient. Ultimately, this move aims to create a more secure Linux experience for users, while also making the development and maintenance process more efficient and engaging for developers.
