This series implements the post-run CB reset suggested by Daniel, reuses the existing save/restore wrapper, and propagates cb_access from freplace programs before their activation.
Patch 1 handles freplace cb_access propagation. Patch 2 marks successful LWT IP header pushes and resets the restored protocol CB after the program runs. Patch 3 contains the selftests, covering direct and freplace CB access, VRF ingress, and packets already marked encapsulated before entering LWT. Changes since v2: - Replace the LWT state tracking and extra CB copy with a post-run reset after bpf_prog_run_save_cb() restores the protocol control block. - Propagate cb_access from freplace programs in a separate prerequisite patch. - Mark only successful BPF_LWT_ENCAP_IP pushes, covering packets already marked encapsulated without treating failed SEG6 operations as completed header replacements. - Select the reset layout from the protocol callback which next consumes the packet, preserving ingress interface and L3-slave state across family changes and initializing the IPv6 network-header offset. - Save and restore the marker around nested LWT runs. - Add selftests for direct and freplace CB access, VRF ingress, and packets already marked encapsulated before entering LWT. Validation: the full KASAN+BTF kernel build passes. All five selftest cases pass with none skipped and no KASAN report, Oops, or panic. The new already-encapsulated case fails on the earlier transition-based implementation and passes with this series. Previous version: https://lore.kernel.org/bpf/[email protected]/ Review discussion: https://lore.kernel.org/bpf/[email protected]/ https://lore.kernel.org/bpf/[email protected]/ Weiming Shi (3): bpf: propagate cb_access from freplace programs bpf: clear stale IPv4 options after LWT encapsulation selftests/bpf: cover stale CB after LWT IP encapsulation include/linux/bpf.h | 2 +- include/linux/filter.h | 8 +- kernel/bpf/syscall.c | 6 + net/core/lwt_bpf.c | 47 +++ .../selftests/bpf/prog_tests/lwt_ip_encap.c | 288 ++++++++++++++++++ .../bpf/progs/lwt_ip_encap_stale_cb.c | 100 ++++++ .../progs/lwt_ip_encap_stale_cb_freplace.c | 32 ++ 7 files changed, 479 insertions(+), 4 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/lwt_ip_encap_stale_cb.c create mode 100644 tools/testing/selftests/bpf/progs/lwt_ip_encap_stale_cb_freplace.c base-commit: 6c096bb08de97cdca051fecddad22cac6a1fd275 -- 2.55.0
