Re: [PATCH v2 bpf-next] selftests/bpf: Fix cgroup_xattr/read_cgroupfs_xattr

[Ihor Solodrai <ihor.solodrai@linux.dev>]

On 6/27/25 2:34 PM, Alexei Starovoitov wrote:
> On Fri, Jun 27, 2025 at 2:19 PM Ihor Solodrai <ihor.solodrai@linux.dev> wrote:
>>
>> On 6/27/25 12:12 PM, Song Liu wrote:
>>> cgroup_xattr/read_cgroupfs_xattr has two issues:
>>>
>>> 1. cgroup_xattr/read_cgroupfs_xattr messes up lo without creating a netns
>>>      first. This causes issue with other tests.
>>>
>>>      Fix this by using a different hook (lsm.s/file_open) and not messing
>>>      with lo.
>>>
>>> 2. cgroup_xattr/read_cgroupfs_xattr sets up cgroups without proper
>>>      mount namespaces.
>>>
>>>      Fix this by using the existing cgroup helpers. A new helper
>>>      set_cgroup_xattr() is added to set xattr on cgroup files.
>>>
>>> Fixes: f4fba2d6d282 ("selftests/bpf: Add tests for bpf_cgroup_read_xattr")
>>> Reported-by: Alexei Starovoitov <ast@kernel.org>
>>> Closes: https://lore.kernel.org/bpf/CAADnVQ+iqMi2HEj_iH7hsx+XJAsqaMWqSDe4tzcGAnehFWA9Sw@mail.gmail.com/
>>> Signed-off-by: Song Liu <song@kernel.org>
>>>
>>> ---
>>> Changes v1 => v2:
>>> 1. Add the second fix above.
>>>
>>> v1: https://lore.kernel.org/bpf/20250627165831.2979022-1-song@kernel.org/
>>> ---
>>>    tools/testing/selftests/bpf/cgroup_helpers.c  |  21 ++++
>>>    tools/testing/selftests/bpf/cgroup_helpers.h  |   4 +
>>>    .../selftests/bpf/prog_tests/cgroup_xattr.c   | 117 ++++--------------
>>>    .../selftests/bpf/progs/read_cgroupfs_xattr.c |   4 +-
>>>    4 files changed, 49 insertions(+), 97 deletions(-)
>>
>> Hi Song.
>>
>> I tried this patch on BPF CI, and it appears it fixes the hanging
>> failure we've been seeing today on bpf-next and netdev.
>> I am going to add it to ci/diffs.
> 
> Applied to bpf-next already.

CI patches apply to all base branches. My understanding is, it's needed
at least for netdev too.