Kernel verifier, builds, and security paths

The kernel lists saw major work on BPF verification depth, kbuild performance, and several security-sensitive networking and virtualization paths. Correctness fixes for scheduling, IPsec, TLS offload, and KVM teardown rounded out the day.

BPF verifier switches to call-graph checks, allows 32 frames

A nine-patch series posted to bpf-next replaces the exponential call-chain walk in the BPF verifier with call-graph analysis and raises MAX_CALL_FRAMES to 32. The change improves how the verifier reasons about chains of calls across the program graph. Complex BPF programs gain both more accurate checking and deeper permitted call stacks.

kbuild series targets large build speedups

A v5 eleven-patch series proposes changes to kbuild, modpost, and objtool that claim 36 to 90 percent faster allmodconfig, incremental, and noop builds. The work focuses on reducing overhead in common full and incremental compile paths. Kernel developers and continuous integration systems stand to gain shorter turnaround times if the measurements hold.

Staging rtl8723bs heap overflow on key add

An RFC patch fixes a heap buffer overflow in the staging rtl8723bs driver inside cfg80211_rtw_add_key() when copying an oversized NL80211_KEY_SEQ value from userspace. The bug allowed unprivileged input to overflow a heap buffer during key installation. Staging wireless drivers remain a frequent source of such memory-safety issues.

SCHED_DEADLINE bandwidth accounting fixes

A v2 twenty-one-patch set submits seventeen fixes for SCHED_DEADLINE bandwidth accounting bugs, including divide-by-zero cases, BUG() triggers on hotplug and affinity changes, and underflows, along with selftests. The series addresses crashes and silent misaccounting under CPU hotplug and affinity shifts. Real-time workloads that rely on deadline scheduling need accurate bandwidth tracking to remain stable.

xfrm ESP IV generation and ESN authentication

A seven-patch series for the ipsec tree fixes AES-GCM nonce reuse and ESN sequence bugs in the Linux kernel xfrm and ESP IPv4 and IPv6 offload paths. Incorrect IV generation can weaken confidentiality, while ESN errors break authentication. IPsec offload users should treat the series as both a correctness and security update.

PMD-level swap entries for anonymous THPs

Version 8 of a thirty-patch series adds PMD-level swap entries so that swapped anonymous transparent huge pages keep huge mappings across swap-out and swap-in instead of splitting to PTEs. The design avoids unnecessary fragmentation of large anonymous mappings under memory pressure. Memory-heavy workloads benefit from preserving THP structure through the swap path.

PSP and kTLS offload cleartext transmission

A v4 seven-patch net series fixes bugs that could transmit PSP and kTLS offloaded packets in cleartext for IPv6 headers, fragments, and ICMP errors. Incorrect fallback on offload paths risked exposing plaintext on the wire. Operators using hardware crypto offload need the fixes to keep traffic confidential.

KVM uaccess hardening on dying VM teardown

The KVM maintainer posted a v4 twenty-three-patch series that fixes uaccess corruption of unrelated processes during VM teardown in nested VMX, plus related hardening. Bad user-access handling while a VM is dying could corrupt memory belonging to other processes. Nested virtualization hosts gain both concrete bug fixes and defensive checks around teardown.