Re: [PATCH bpf-next v3 3/3] selftests/bpf: Add iter subtest using lskel in global_data_init

[Leon Hwang]

On 2026/9/18 13:05, bot+bpf-ci@xxxxxxxxxx wrote:
>> In test_global_percpu_data.c, dump_percpu_data is defined after two
>> non-autoload SEC("?kprobe") programs (verifier_strncmp and
>> verifier_snprintf). If bpftool does not skip non-autoload programs when
>> generating light skeletons, dump_percpu_data.prog_fd is left invalid or
>> unpopulated.
>>
>> Factor out a test_global_percpu_data_iter_fd() helper that operates
>> directly on prog/map file descriptors, and add an iter_lskel subtest to
>> verify that dump_percpu_data is properly loaded and executes correctly
>> when using the light skeleton.
>>
>> Fixes: 4c9241bd731a ("selftests/bpf: Add tests to verify global percpu data")
>> Fixes: 1ed2294b31fc ("selftests/bpf: Test verifier log for global percpu data")
>> Signed-off-by: Thiébaud Weksteen <tweek@xxxxxxxxxx>
> 
> Are the Fixes: tags appropriate for this commit? This patch only adds new
> test coverage (a new iter_lskel subtest) and refactors existing test code
> (factoring out test_global_percpu_data_iter_fd() with no behavioral change
> to the existing "iter" subtest). It doesn't fix anything that
> 4c9241bd731a or 1ed2294b31fc got wrong.
> 
> The bug being tested is in bpftool, introduced by d510296d331a
> ("bpftool: Use syscall/loader program in "prog load" and "gen skeleton"
> command.") and actually fixed by the two preceding patches in this series
> (202ee90dee368 and 843762e6f4665), both of which already carry the correct
> Fixes: d510296d331a tag.

Agreed.

The Fixes: tags of this patch can be dropped.

Others lgtm:

Acked-by: Leon Hwang <leon.hwang@xxxxxxxxx>

> 
> There's also a backport concern. The Fixes: tags make this patch a
> candidate for AUTOSEL/stable pickup independently of 202ee90dee368 and
> 843762e6f4665. Since this is the last patch of the series, backporting it
> alone would land the new iter_lskel subtest in a tree with the unfixed
> bpftool, where skel->progs.dump_percpu_data.prog_fd is left at 0 and
> bpf_link_create(0, 0, BPF_TRACE_ITER, &opts) fails. The subtest would fail
> by construction.
> 
> Should the Fixes: tags be removed, or if they're intended to be kept,
> should the dependency on the two bpftool patches be stated via
> Cc: <stable@xxxxxxxxxxxxxxx> prerequisite lines?
> 
> 
> ---
> AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
> See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md
> 
> CI run summary: https://github.com/kernel-patches/bpf/actions/runs/35306404663