Kernel builds, Rust SPDM, and futex RFCs

Kernel traffic on 2026-10-16 was dominated by a large kbuild series claiming major compile-time gains, alongside Rust SPDM work and a contested futex design. Security and reliability items also appeared in tracing, NVMe multipath recovery, hotplug, MGLRU, and filesystem error paths.

kbuild series targets large build speedups

A 22-patch v4 series proposes changes to kbuild that the authors claim deliver 36 to 90 percent faster kernel builds. The work centers on toolchain caching, modpost and objtool adjustments, parallel Rust and objtool execution, and pigz. Build-system and distribution maintainers have a direct stake in whether the claimed gains hold under review.

Rust SPDM requester lands as v4

A 22-patch v4 series adds a Rust implementation of SPDM as a kernel requester. The stated goal is safer parsing of complex, untrusted authentication data. The series continues the use of Rust for kernel paths that handle externally supplied protocol messages.

FUTEX_PING RFC draws locking concerns

An RFC series introduces FUTEX_PING, a stealable futex built on proxy execution for priority-inheritance locks. Discussion, including comments from Zijlstra and others, raised deadlock and locking-order questions. Scheduler and locking developers will need to weigh the design against those objections.

Tracing path misses access_ok on syscall args

A bug report shows that syscall fault tracing can call __copy_from_user without access_ok, creating a potential kernel memory leak. A fix was proposed and reviewed by Greg KH and Steven Rostedt. The issue is security-relevant for any system that enables the affected tracing paths.

NVMe TP8028 multipath failure recovery

A v6 18-patch series implements NVMe TP8028 cross-controller reset for rapid path failure recovery on both host and target. The work improves multipath resilience when individual controllers fail. Operators running multipath NVMe storage are the primary audience.

CPU hotplug cut on large x86 systems

An eight-patch v1 series changes x86, scheduler, and mm paths to reduce WBINVD, topology rebuilds, deadline accounting, and vmstat cost during CPU hotplug. The authors report a 21x speedup on a 480-CPU Xeon. Large-system operators gain faster hotplug for maintenance and capacity changes.

MGLRU frequency-guided promotion

Kairui Song posted a v4 series adding frequency-guided promotion to MGLRU and cleaning up related refs flags. The patches refine how multi-gen LRU decides which pages to promote. Memory-management behavior under mixed workloads is the practical impact.

Filesystems stop setting SB_RDONLY unsafely

A 28-patch RFC stops filesystems from setting SB_RDONLY after errors without holding s_umount. The change addresses freeze and thaw races and hangs in hfs, ntfs, gfs2, zonefs, and other filesystems. More consistent error handling across those code bases is the intended result.