Kbuild speedups, Apple USB4, and stable security fixes

Kernel traffic on 2026-09-10 was led by a large kbuild performance series and initial USB4 support for Apple M-series SoCs, with BPF and memory-management redesigns close behind. Several security fixes also moved through the stable trees covering ntfs3, seccomp, and a staging wireless driver.

kbuild series speeds kernel builds

A 23-patch kbuild series on linux-kernel reports 20-36% faster allmodconfig builds and larger gains for incremental and noop cases on x86 and arm64. The work targets the kernel build system itself rather than a single subsystem. Developers who rebuild often have a direct stake in whether the series lands.

USB4 and Thunderbolt for Apple M1/M2/M3

A v2 22-patch series adds initial USB4 and Thunderbolt support, including ACIO, NHI, and DART pieces plus device tree nodes, for Apple M1, M2, and M3 SoCs. The patches open the interconnect path that many Apple silicon machines depend on for docks and peripherals. Mainline usability of those platforms improves if the series is accepted.

BPF verifier quadratic CFG and gotox fixes

A six-patch BPF series fixes quadratic successor rescans in bpf_compute_scc and unbounded gotox edges in the verifier. Crafted programs could otherwise drive long CPU stalls during verification. The changes matter for verifier DoS resistance on systems that allow unprivileged BPF.

mm fbatch series reduces lru drain calls

Hugh Dickins posted a v2 26-patch series that removes most lru_add_drain and lru_add_drain_all calls by leaving folios on per-cpu fbatches with PG_lru set. The redesign simplifies paths that previously forced frequent drains across CPUs. Memory-management reviewers tracking folio batching will want to examine the approach.

mlx5 VFIO selftest support

A v5 10-patch netdev series adds an mlx5 VFIO selftest driver. The author states the bulk was written with Claude AI over four days and then heavily refactored. The work supplies automated coverage for VFIO behavior on mlx5 hardware.

Stable: ntfs3 slab out-of-bounds write

Greg KH queued a stable backport fixing a slab-out-of-bounds write in ntfs3 ni_create_attr_list reachable from a crafted image. The bug is a memory-corruption path in the NTFS3 driver. Stable users mounting untrusted NTFS media are the audience for the fix.

Stable: seccomp bypass with ptrace TSYNC

Stable trees received a fix for a seccomp filter bypass race when TSYNC runs during a ptrace stop inside syscall_trace_enter. Under that timing, seccomp restrictions could be skipped. The change closes a privilege-boundary hole for traced workloads that use TSYNC.

Stable: rtl8723bs WPS attribute overflow

A stable backport fixes an out-of-bounds read and stack overflow in staging rtl8723bs rtw_get_wps_attr during WPS attribute parsing. Crafted input could corrupt the stack in that path. Systems still carrying the staging driver pick up the hardening with the stable update.