[PATCH bpf-next v3 0/3] bpf: expose cgroup preorder attachment state to userspace

[Hui Su <sh_def@163.com>]

The BPF_F_PREORDER attach flag changes the ordering of programs in the
effective cgroup program array, but BPF_PROG_QUERY did not report the
per-program flag. This series exposes that state and updates bpftool to
display, accept, and document this flag.

The series is split into three patches:

1. Report BPF_F_PREORDER in direct cgroup program queries.
2. Add selftests for direct and link-based program queries.
3. Add bpftool support for text, JSON, command-line, completion, and
   documentation handling of BPF_F_PREORDER.

Changes in v3:
- Simplify the changelogs for patches 1 and 2.
- Simplify the ATTACH_FLAGS synopsis and represent attach flags as an
  array in JSON output, as suggested by Quentin Monnet.
- Widen the plain-text AttachFlags column for combined flags.
- Address checkpatch line-length and alignment warnings.

Testing:
- PASS: cgroup_mprog_opts, cgroup_preorder, and bpftool cgroup
  plain-text/JSON smoke (x86_64 QEMU/KVM).
- PASS: bpftool build, Documentation build, bash -n, and checkpatch on
  generated v3 patches.

Previous versions:
v2: https://lore.kernel.org/bpf/20260919094400.600585-1-sh_def@163.com/
v1: https://lore.kernel.org/bpf/20260918172407.3459188-1-sh_def@163.com/

Hui Su (3):
  bpf: Report BPF_F_PREORDER in cgroup program queries
  selftests/bpf: Test querying BPF_F_PREORDER cgroup attachments
  bpftool: Add support for BPF_F_PREORDER cgroup attach flag

 kernel/bpf/cgroup.c                           | 16 +--
 .../bpftool/Documentation/bpftool-cgroup.rst  | 25 +++--
 tools/bpf/bpftool/bash-completion/bpftool     |  4 +-
 tools/bpf/bpftool/cgroup.c                    | 99 +++++++++++++------
 .../bpf/prog_tests/cgroup_mprog_opts.c        | 71 ++++++++++++-
 5 files changed, 166 insertions(+), 49 deletions(-)


base-commit: 79dc258c9392051420a26f1504c647bd3d27c66a
-- 
2.55.0