Re: [PATCH v3 bpf-next 0/4] Introduce bpf_cgroup_read_xattr

[Alexei Starovoitov]

On Mon, Jun 23, 2025 at 4:03 AM Christian Brauner <brauner@xxxxxxxxxx> wrote:
>
> On Sun, 22 Jun 2025 23:38:50 -0700, Song Liu wrote:
> > Introduce a new kfunc bpf_cgroup_read_xattr, which can read xattr from
> > cgroupfs nodes. The primary users are LSMs, cgroup programs, and sched_ext.
> >
>
> Applied to the vfs-6.17.bpf branch of the vfs/vfs.git tree.
> Patches in the vfs-6.17.bpf branch should appear in linux-next soon.

Thanks.
Now merged into bpf-next/master as well.

> Please report any outstanding bugs that were missed during review in a
> new review to the original patch series allowing us to drop it.

bugs :(

> It's encouraged to provide Acked-bys and Reviewed-bys even though the
> patch has now been applied. If possible patch trailers will be updated.

Pls don't. Keep it as-is, otherwise there will be merge conflicts
during the merge window.

> Note that commit hashes shown below are subject to change due to rebase,
> trailer updates or similar. If in doubt, please check the listed branch.
>
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
> branch: vfs-6.17.bpf
>
> [1/4] kernfs: remove iattr_mutex
>       https://git.kernel.org/vfs/vfs/c/d1f4e9026007
> [2/4] bpf: Introduce bpf_cgroup_read_xattr to read xattr of cgroup's node
>       https://git.kernel.org/vfs/vfs/c/535b070f4a80
> [3/4] bpf: Mark cgroup_subsys_state->cgroup RCU safe
>       https://git.kernel.org/vfs/vfs/c/1504d8c7c702
> [4/4] selftests/bpf: Add tests for bpf_cgroup_read_xattr
>       https://git.kernel.org/vfs/vfs/c/f4fba2d6d282

Something wrong with this selftest.
Cleanup is not done correctly.

./test_progs -t lsm_cgroup
Summary: 1/2 PASSED, 0 SKIPPED, 0 FAILED
./test_progs -t lsm_cgroup
Summary: 1/2 PASSED, 0 SKIPPED, 0 FAILED
./test_progs -t cgroup_xattr
Summary: 1/8 PASSED, 0 SKIPPED, 0 FAILED
./test_progs -t lsm_cgroup
test_lsm_cgroup_functional:PASS:bind(ETH_P_ALL) 0 nsec
(network_helpers.c:121: errno: Cannot assign requested address) Failed
to bind socket
test_lsm_cgroup_functional:FAIL:start_server unexpected start_server:
actual -1 < expected 0
(network_helpers.c:360: errno: Bad file descriptor) getsockopt(SOL_PROTOCOL)
test_lsm_cgroup_functional:FAIL:connect_to_fd unexpected
connect_to_fd: actual -1 < expected 0
test_lsm_cgroup_functional:FAIL:accept unexpected accept: actual -1 < expected 0
test_lsm_cgroup_functional:FAIL:getsockopt unexpected getsockopt:
actual -1 < expected 0
test_lsm_cgroup_functional:FAIL:sk_priority unexpected sk_priority:
actual 0 != expected 234
...
Summary: 0/1 PASSED, 0 SKIPPED, 1 FAILED


Song,
Please follow up with the fix for selftest.
It will be in bpf-next only.