Re: [PATCH bpf-next v2 3/3] selftests/bpf: Verify program FD after non-autoload programs in lskel

[Quentin Monnet <qmo@kernel.org>]

2026-09-17 11:06 UTC+1000 ~ Thiébaud Weksteen <tweek@google.com>
> On Thu, Sep 10, 2026 at 3:49 PM Leon Hwang <leon.hwang@linux.dev> wrote:
>>
>> On 9/9/26 12:24, Thiébaud Weksteen wrote:
>>> In test_global_percpu_data.c, dump_percpu_data is defined after two
>>> non-autoload SEC("?kprobe") programs (verifier_strncmp and
>>> verifier_snprintf). Verify in test_global_percpu_data_lskel() that
>>> lskel->progs.dump_percpu_data.prog_fd is properly populated (> 0) when
>>> loaded via the light skeleton.
>>>
>>> Signed-off-by: Thiébaud Weksteen <tweek@google.com>
>>> ---
>>> No changes since v1.
>>
>> The Fixes tags of v1 are dropped.
>>
>>>
>>>  tools/testing/selftests/bpf/prog_tests/global_data_init.c | 2 ++
>>>  1 file changed, 2 insertions(+)
>>>
>>> diff --git a/tools/testing/selftests/bpf/prog_tests/global_data_init.c b/tools/testing/selftests/bpf/prog_tests/global_data_init.c
>>> index 7c539cbcf3a1..ebda60200b71 100644
>>> --- a/tools/testing/selftests/bpf/prog_tests/global_data_init.c
>>> +++ b/tools/testing/selftests/bpf/prog_tests/global_data_init.c
>>> @@ -214,6 +214,8 @@ static void test_global_percpu_data_lskel(void)
>>>       lskel = test_global_percpu_data_lskel__open_and_load();
>>>       if (!ASSERT_OK_PTR(lskel, "test_global_percpu_data_lskel__open_and_load"))
>>>               goto out;
>>> +     if (!ASSERT_GT(lskel->progs.dump_percpu_data.prog_fd, 0, "dump_percpu_data.prog_fd"))
>>> +             goto out;
>>
>> When the light skeleton does not skip the non-autoload progs,
>> lskel->progs.dump_percpu_data.prog_fd is 0, actually.
>>
>> But, theoretically, this ASSERT_GT() is not good enough to prove the FD
>> is the correct FD of dump_percpu_data prog.
>>
>> How about running the iter subtest against the lskel? Factor out
>> test_global_percpu_data_iter_fd() helper first. Then, add an iter
>> subtest using lskel.
>> When factoring out test_global_percpu_data_iter_fd() helper, pls change
>> 'do { } while (0);' to '{ /* no-op */ }' btw.
>>
> 
> Thanks for the review Leon. That sounds good, I can implement these
> changes. I am just waiting for Quentin's feedback on the first patch
> in this series before spinning up a new patch set.
> 


Apologies for the delay. Patch 1 looks good to me, I just posted some
minor suggestions regarding comments. Thank you!

Quentin