Kernel RCU fixes, ext4 cleanup, and mm disputes

Security patches for CAN and BPF led the day's kernel traffic, while maintainers clashed over AI-assisted submissions and a broken crypto driver. Memory management proposals and an ext4 simplification RFC rounded out the technical discussions.

Missing RCU synchronization in CAN BCM

A patch adds the missing synchronize_rcu() call inside bcm_delete_rx_op() to close an RCU race in the AF_CAN BCM code. The race permits a timer use-after-free reachable from an unprivileged socket. The fix removes a local denial-of-service or escalation path in Controller Area Network support.

RFC to retire ext4 inline data writes

An RFC series proposes phasing out the inline_data write paths for regular ext4 files. The authors cite more than fifteen recent bug fixes and eight CVEs that originated in the complex locking of those paths. The change would simplify a repeatedly problematic corner of the filesystem.

Maintainer rejects per-VMA lock series over AI patches

David Hildenbrand declines to review Rik van Riel's twelve-patch RFC that introduces per-VMA locking inside __access_remote_vm. The refusal is based on the patches appearing AI-generated. The exchange underscores growing friction over contribution provenance in the memory-management subsystem.

Ten BPF verifier and IRQ-context findings

A report posted to the BPF list details ten validated issues that fall into two shared root-cause classes affecting the verifier and IRQ context. Reference patches are supplied with the findings. The issues bear on the safety guarantees relied upon by eBPF programs and their users.

Dispute over removal of broken QCE crypto driver

A patch that deletes the long-marked-BROKEN qce crypto driver triggers extended maintainer debate. Participants argue over residual in-kernel users, removal policy, and possible future security features. The outcome may influence how other obsolete hardware crypto drivers are handled.

Reclaim-storm fixes for defrag_mode

A four-patch v2 series stops reclaim storms that appear when defrag_mode equals 1. Non-movable allocation requests are made to participate in pageblock production. The adjustment stabilizes reclaim under memory fragmentation.

NUMA balancing restored for shmem

A patch corrects a long-standing defect that silently disabled automatic NUMA balancing on shmem. Memory-management maintainers examine possible KVM side effects and required documentation updates. Shared-memory workloads regain the balancing behavior originally intended.

btrfs folio lock leak in 7.2-rc1

A regression report isolates a folio lock leak inside btrfs writepage_delalloc() for large data folios that were dirtied through GUP without subpage bits. A proposed fix is under active discussion. The leak can leave locks held on recent kernels that exercise this path.