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

[Eduard Zingerman <eddyz87@gmail.com>]

On Fri, 2025-06-27 at 12:12 -0700, 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/
> ---

This fixes ./test_progs -j -t cgroup for me.
Changes seem to reflect logic of the original test.

Tested-by: Eduard Zingerman <eddyz87@gmail.com>

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