On Thu, Feb 17, 2022 at 03:18 PM +01, Ilya Leoshkevich wrote:
> On Wed, 2022-02-16 at 13:44 -0800, Andrii Nakryiko wrote:
>> On Wed, Feb 9, 2022 at 10:43 AM Jakub Sitnicki <jakub@xxxxxxxxxxxxxx>
>> wrote:
[...]
>> > + /* Load from remote_port field with zero padding (backward
>> > compatibility) */
>> > + val_u32 = *(__u32 *)&ctx->remote_port;
>> > + if (val_u32 != bpf_htonl(bpf_ntohs(SRC_PORT) << 16))
>> > + return SK_DROP;
>> > +
>>
>> Jakub, can you please double check that your patch set doesn't break
>> big-endian architectures? I've noticed that our s390x test runner is
>> now failing in the sk_lookup selftest. See [0]. Also CC'ing Ilya.
>
> I agree that this looks like an endianness issue. The new check seems
> to make little sense on big-endian to me, so I would just #ifdef it
> out.
We have a very similar check for a load from context in
progs/test_sock_fields.c, which is not causing problems:
static __noinline bool sk_dst_port__load_word(struct bpf_sock *sk)
{
__u32 *word = (__u32 *)&sk->dst_port;
return word[0] == bpf_htonl(0xcafe0000);
}
So I think I just messed something up here. Will dig into it.
[...]
