On Fri, 24 Jan 2025 11:22:16 -0800, Martin KaFai Lau wrote:
> On 1/23/25 6:45 PM, Stanislav Fomichev wrote:
>> On 01/23, Martin KaFai Lau wrote:
>>> On 1/23/25 11:18 AM, Stanislav Fomichev wrote:
>>>> On 01/22, Shigeru Yoshida wrote:
>>>>> The function bpf_test_init() now returns an error if user_size
>>>>> (.data_size_in) is less than ETH_HLEN, causing the tests to
>>>>> fail. Adjust the data size to ensure it meets the requirement of
>>>>> ETH_HLEN.
>>>>>
>>>>> Signed-off-by: Shigeru Yoshida <syoshida@xxxxxxxxxx>
>>>>> ---
>>>>> .../testing/selftests/bpf/prog_tests/xdp_cpumap_attach.c | 4 ++--
>>>>> .../testing/selftests/bpf/prog_tests/xdp_devmap_attach.c | 8 ++++----
>>>>> 2 files changed, 6 insertions(+), 6 deletions(-)
>>>>>
>>>>> diff --git
>>>>> a/tools/testing/selftests/bpf/prog_tests/xdp_cpumap_attach.c
>>>>> b/tools/testing/selftests/bpf/prog_tests/xdp_cpumap_attach.c
>>>>> index c7f74f068e78..df27535995af 100644
>>>>> --- a/tools/testing/selftests/bpf/prog_tests/xdp_cpumap_attach.c
>>>>> +++ b/tools/testing/selftests/bpf/prog_tests/xdp_cpumap_attach.c
>>>>> @@ -52,10 +52,10 @@ static void test_xdp_with_cpumap_helpers(void)
>>>>> ASSERT_EQ(info.id, val.bpf_prog.id, "Match program id to cpumap entry
>>>>> prog_id");
>>>>> /* send a packet to trigger any potential bugs in there */
>>>>> - char data[10] = {};
>>>>> + char data[ETH_HLEN] = {};
>>>>> DECLARE_LIBBPF_OPTS(bpf_test_run_opts, opts,
>>>>> .data_in = &data,
>>>>> - .data_size_in = 10,
>>>>> + .data_size_in = sizeof(data),
>>>>> .flags = BPF_F_TEST_XDP_LIVE_FRAMES,
>>>>> .repeat = 1,
>>>>> );
>>>>
>>>> We should still keep 10, but change the ASSERT_OK below to expect the
>>>> error instead. Looking at the comment above, the purpose of the test
>>>> is to exercise that error case.
>>>>
>>>
>>> I think the bpf_prog_test_run_opts in this dev/cpumap test is to check
>>> the
>>> bpf_redirect_map() helper, so it expects the bpf_prog_test_run_opts to
>>> succeed.
>>>
>>> It just happens the current data[10] cannot trigger the fixed bug
>>> because
>>> the bpf prog returns a XDP_REDIRECT instead of XDP_PASS, so
>>> xdp_recv_frames
>>> is not called.
>>>
>>> To test patch 1, a separate test is probably needed to trigger the bug
>>> in
>>> xdp_recv_frames() with a bpf prog returning XDP_PASS.
>> Ah, yes, you're right, I missed the remaining parts that make sure
>> the redirect happens
>
> Thanks for confirming and the review.
>
> Applied the fix.
Hi Martin, Stanislav,
Thank you for your comments and feedback!
> Shigeru, please followup with a selftest to test the "less than
> ETH_HLEN" bug addressed in Patch 1. You can reuse some of the
> boilerplate codes from the xdp_cpumap_attach.c. The bpf prog can
> simply be "return XDP_PASS;" and ensure that
> BPF_F_TEST_XDP_LIVE_FRAMES is included in the
> bpf_test_run_opts. Thanks.
I'm not very familiar with bpf and its selftests, but I will try to
make a new test according to your advice.
Thanks,
Shigeru
