Support safety attributes in Rust for Linux

[zjp-CN]

Context - Rust for Linux - Safety Standard

• RustWeek - All Hands - Naming safety requirements & invariants (2025.05)
  • Meeting note: Function contracts and type invariants specification (2025.05)
  • Predrag's proposal Automated checking of unsafe code requirements (2024.10)
• Slides: Rust Safety Standard - Increasing the Correctness of unsafe Code (2024.09) ⭐⭐⭐
  • LWN article: A discussion of Rust safety documentation (2024.09)
  • LWN article: Standards for use of unsafe Rust in the kernel (2024.08)
• RFC PATCH 0/5 Introduce the Rust Safety Standard (2024.07)
• Safety comments and atomicity requirements (2024.03)

Old

Idea

Since tag-std currently is a PoC, there are several ways to apply it to R4L

• write a universal tool that can apply to any Rust project
• or enhance klint a static analysis tool/infrastructure in R4L
• or write a universal library that can be shared in different workflows/tools
  • Feat: add tag-std and cargo-tag-std demo by driving rustc #1 demonstrates a normal workflow for single file and most cargo-based projects
  • libstd needs a workflow: Black arts of verifying libcore/libstd os-checker/distributed-verification#52
  • R4L needs its own: klint can reuse the library
  • the main downside is multi-toolchains problem: StableMir should ideally solve this

[hxuhack]

write a universal tool that can apply to any Rust project or enhance klint a static analysis tool/infrastructure in R4L.

This work was originally not intended to support all Rust programs, but focused solely on the standard library. The main reason is that the safety properties may not generalize well or reach convergence. However, following a request from Rust-for-Linux and inspired by the work of asterinas, we believe it may be possible to extract a set of general safety tags for Rust-based operating systems as well. We’ve decided to begin exploring this direction and will keep our findings updated in os-sp.

[zjp-CN]

A month ago, we filed RFC#3842: Safety Tags, proposing a lighter syntax that pursues two concrete goals:

1. Attach safety tags to the standard library (including libcore) by turning the ad-hoc safety comments of today into machine-checked annotations.
2. Surface those tags inside Clippy and rust-analyzer so developers get first-class, real-time feedback on unsafe-code usage.

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Team members are now systematically applying safety properties to

• the standard library, through verify-rust-std and RAPx
• the unsafe code in Rust-for-Linux
• Asterinas’s ostd crate, whose entire unsafe surface has already been isolated

Our CI already tracks the tagged snapshots of all three projects.

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Projects that are also interested in safety tags:

• Bevy (see this zulip topic)