linux-kernel - [PATCH bpf-next v2 0/2] bpf: Disallow BPF_F

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Message-ID: <20260123055658.372869-1-leon.hwang@linux.dev>
Date: Fri, 23 Jan 2026 13:56:56 +0800
From: Leon Hwang <leon.hwang@...ux.dev>
To: bpf@...r.kernel.org
Cc: Alexei Starovoitov <ast@...nel.org>,
	Daniel Borkmann <daniel@...earbox.net>,
	John Fastabend <john.fastabend@...il.com>,
	Andrii Nakryiko <andrii@...nel.org>,
	Martin KaFai Lau <martin.lau@...ux.dev>,
	Eduard Zingerman <eddyz87@...il.com>,
	Song Liu <song@...nel.org>,
	Yonghong Song <yonghong.song@...ux.dev>,
	KP Singh <kpsingh@...nel.org>,
	Stanislav Fomichev <sdf@...ichev.me>,
	Hao Luo <haoluo@...gle.com>,
	Jiri Olsa <jolsa@...nel.org>,
	Shuah Khan <shuah@...nel.org>,
	Leon Hwang <leon.hwang@...ux.dev>,
	linux-kernel@...r.kernel.org,
	linux-kselftest@...r.kernel.org,
	kernel-patches-bot@...com
Subject: [PATCH bpf-next v2 0/2] bpf: Disallow BPF_F_LOCK with mixed special fields

Disallow combining BPF_F_LOCK with map values that mix bpf_spin_lock and
other special BTF fields, which may lead to undefined behavior. Such cases
are now rejected with -EOPNOTSUPP.

Map update flag validation is centralized in
bpf_map_check_op_flags() and reused across array, hash, local-storage,
and task-storage update paths, with selftests added to verify the new
behavior.

Changes:
v1 -> v2:
* Reject any unknown flag bits in map_flags when updating maps (per AI review).
* v1: https://lore.kernel.org/bpf/20260122153120.69249-1-leon.hwang@linux.dev/

Leon Hwang (2):
  bpf: Disallow BPF_F_LOCK with mixed special fields and centralize flag
    checks
  selftests/bpf: Add tests to verify BPF_F_LOCK restrictions

 include/linux/bpf.h                           |  7 ++
 kernel/bpf/arraymap.c                         | 11 ++-
 kernel/bpf/bpf_local_storage.c                |  7 --
 kernel/bpf/bpf_task_storage.c                 |  3 -
 kernel/bpf/hashtab.c                          |  8 +--
 kernel/bpf/syscall.c                          |  4 +-
 .../selftests/bpf/prog_tests/map_lock.c       | 70 +++++++++++++++++++
 .../selftests/bpf/progs/test_map_lock.c       | 31 +++++++-
 8 files changed, 117 insertions(+), 24 deletions(-)

--
2.52.0