Greg Kroah‑Hartman Calls for More Rust Contributors to the Linux Kernel

Announcement

During the opening keynote of Rust Week 2026 in Utrecht, Netherlands, Linux veteran Greg Kroah‑Hartman (Linux’s “second‑in‑command” and long‑time stable maintainer) delivered a data‑rich presentation on the state of Rust inside the kernel. He concluded with a direct appeal: the Linux project needs more Rust developers to keep the security and productivity gains moving forward.

Technical specs

Current Rust footprint in the kernel

• Modules written in Rust: 27 (as of the 6.9‑rc1 merge window)
• Lines of Rust code: ~120 k, representing roughly 3 % of the total kernel source tree.
• Subsystems with Rust components: drivers (e.g., i2c, spi), networking (netfilter), and the new rust/usb stack.

Performance and safety numbers

Metric	C implementation	Rust implementation	Δ
Interrupt latency (average)	1.84 µs	1.62 µs	‑12 %
Memory safety bugs reported (2024‑2025)	48 (C‑only)	0 (Rust)	‑100 %
Compile time (full tree)	22 min	24 min (with rustc incremental)	+9 %

The latency reduction stems from Rust’s zero‑cost abstractions and stricter borrow‑checker guarantees that eliminate several pointer‑manipulation paths. The safety metric is more striking: no memory‑corruption bugs have been filed against Rust‑only code, compared with an average of 0.9 bugs per 1 k lines of C code.

Toolchain integration

• Rustc version used: 1.77.0 (nightly) with the rustc_codegen_gcc backend to align with the kernel’s GCC toolchain.
• Build system: The kernel now ships a rustc wrapper script (scripts/rustc-wrapper) that injects the appropriate -C target-cpu=native and -Z build-std=core,alloc flags.
• Testing pipeline: Each Rust change triggers both make kselftest and a dedicated cargo test --target=kernel suite, adding roughly 15 % more CI runtime but catching bugs before they reach the mainline.

Trade‑offs

Aspect	Benefit	Cost
Security	Memory‑safety guarantees, no undefined‑behavior UB	Requires developers to learn Rust’s ownership model
Developer productivity	Faster iteration on driver prototypes (type‑checked APIs)	Longer initial compile times, larger toolchain footprint
Maintainability	Clearer API contracts, fewer hidden side‑effects	Smaller pool of contributors familiar with both kernel internals and Rust

Market implications

Talent pipeline

The Linux kernel’s shift toward Rust creates a new niche for engineers skilled in low‑level systems programming and safe languages. According to the 2025 Stack Overflow Developer Survey, 9 % of respondents listed Rust as a primary language, up from 5 % in 2022. If the kernel can attract even half of that cohort, the contributor base could double within two years.

Supply‑chain resilience

Rust’s deterministic memory model reduces the likelihood of latent security flaws that often require emergency patches. Fewer emergency releases translate to a more stable supply of kernel binaries for OEMs, cloud providers, and embedded device manufacturers. For example, the Open Compute Project estimates that a 10 % reduction in post‑release patches could save $3 M annually across its member base.

Competitive pressure

Other open‑source OS projects—such as Redox OS and Microsoft’s Windows Subsystem for Linux—have already adopted Rust for core components. By expanding its Rust developer pool, Linux can stay ahead of these initiatives and retain its position as the default platform for security‑critical workloads, from autonomous vehicles to edge AI.

Call to action

Greg Kroah‑Hartman’s presentation (embedded below) outlines concrete steps for interested contributors:

1. Join the rust/kernel mailing list – the primary venue for design reviews.
2. Start with the “Hello‑World” driver tutorial – available in the kernel’s Documentation/rust directory.
3. Contribute to the rust/usb subsystem – currently seeking reviewers for the new endpoint handling code.
4. Participate in the quarterly Rust‑Kernel Hackathon – hosted jointly by the Linux Foundation and the Rust Foundation.

Developers who already maintain C subsystems are encouraged to prototype a small portion in Rust and submit a pull request for feedback. The kernel’s maintainers have pledged to allocate 5 % of the next merge window’s review capacity specifically for Rust contributions.

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Watch the full keynote and the fireside chat below.

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