Linux Kernel 2025: Rust Rise, Torvalds & Scheduler

Key Takeaways:

• Rust moved from experiment to mainstream in the Linux kernel, but it also produced the kernel's first Rust CVE this year.
• Linus Torvalds actively shaped decisions: rejecting low-quality patches, enforcing formatting changes, and influencing Rust policy.
• Meta adopted the Steam Deck–designed scheduler on its hyperscaler servers — a surprising cross-over from handheld to datacenter.
• Bcachefs was removed from mainline; several maintainers stepped down and new drivers (NOVA, NTSYNC) advanced.

Year in review: what defined Linux kernel 2025

The Linux kernel community saw intense activity across code, policy and personnel in 2025. Rust transitioned from a long-running experiment into a supported kernel language, while Linus Torvalds repeatedly intervened to steer quality and policy.

Rust: accepted, criticized and battle-tested

Rust was formally declared "here to stay" when lead developer Miguel Ojeda posted a patch to conclude the experiment. Red Hat and Greg Kroah‑Hartman publicly encouraged new drivers to be written in Rust.

But adoption wasn't friction-free. The kernel recorded its first CVE tied to Rust code, and Torvalds publicly criticized some Rust format checking as "completely crazy," prompting fixes merged into the 6.18 tree. Christoph Hellwig stepped down from a DMA helper maintainer role amid disputes over Rust bindings, highlighting ongoing governance tensions.

Torvalds' year of direct action

Linus Torvalds repeatedly used his authority to enforce standards: rejecting low-quality RISC‑V changes, tightening rules on useless "Link:" tags in commit messages, and pressing for clearer formatting. Reports also surfaced that Torvalds would override maintainers who block Rust code — an escalation showing how high the stakes are for language and style decisions in kernel development.

Filesystems, drivers and maintainers

Bcachefs — once a promising alternative — was first marked "externally maintained" and later removed from mainline around the 6.18 cycle. That shift, alongside longtime contributors stepping back (including Josef Bacik leaving Meta), changes maintenance dynamics for core storage subsystems.

Open-source efforts continued: XTX Markets open‑sourced TernFS, and Btrfs remained critical infrastructure with real cost savings reported at Meta.

Driver progress: NOVA and NTSYNC

New Rust-written drivers advanced. Red Hat engineers submitted the NOVA NVIDIA driver targeting RTX 20/Turing+ GPUs, while the NTSYNC driver — designed to better map Windows NT sync primitives — progressed toward merging to improve Wine/Proton gaming performance.

Performance experiments and architecture

Several infrastructure experiments showed promise. Google-originated Address Space Isolation (ASI) saw its I/O overhead trimmed from ~70% to ~13%, making it far more practical. Swap Tables work indicated potential large performance and memory-use gains. Bytedance proposed RPAL to speed inter-process communication, and an experimental port of the Linux kernel to WebAssembly demonstrated unusual but interesting portability.

Outlook for 2026

Expect continued Rust expansion, more debate over maintainer roles, and cross-domain innovations — from handheld scheduler design being repurposed by hyperscalers to filesystem and driver churn. The kernel community remains active and contentious, but progress continued at a rapid pace through 2025.