netdev - Re: [PATCH net-next] samples/bpf: Fix compilation issue in redirect dummy program

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Message-ID: <f3992661-3161-d75e-4528-db9af188c519@mellanox.com>
Date:   Thu, 31 Aug 2017 15:29:46 +0300
From:   Tariq Toukan <tariqt@...lanox.com>
To:     Daniel Borkmann <daniel@...earbox.net>,
        Jesper Dangaard Brouer <brouer@...hat.com>,
        Tariq Toukan <tariqt@...lanox.com>
Cc:     "David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
        Eran Ben Elisha <eranbe@...lanox.com>, ys114321@...il.com,
        alexei.starovoitov@...il.com
Subject: Re: [PATCH net-next] samples/bpf: Fix compilation issue in redirect
 dummy program



On 31/08/2017 2:43 PM, Daniel Borkmann wrote:
> On 08/31/2017 01:27 PM, Jesper Dangaard Brouer wrote:
>> On Thu, 31 Aug 2017 14:16:39 +0300
>> Tariq Toukan <tariqt@...lanox.com> wrote:
>>
>>> Fix compilation error below:
>>>
>>> $ make samples/bpf/
>>>
>>> LLVM ERROR: 'xdp_redirect_dummy' label emitted multiple times to
>>> assembly file
>>> make[1]: *** [samples/bpf/xdp_redirect_kern.o] Error 1
>>> make: *** [samples/bpf/] Error 2
>>>
>>> Fixes: 306da4e685b4 ("samples/bpf: xdp_redirect load XDP dummy prog 
>>> on TX device")
>>> Signed-off-by: Tariq Toukan <tariqt@...lanox.com>
>>> ---
>>
>> Acked-by: Jesper Dangaard Brouer <brouer@...hat.com>
> 
> Acked-by: Daniel Borkmann <daniel@...earbox.net>
> 
>> What LLVM/clang version do you use?

clang version 3.8.0 (tags/RELEASE_380/final)

>>
>> I don't see this compile error, and I have:
>>   $ clang --version
>>   clang version 3.9.1 (tags/RELEA
> 
> I'm seeing the error as well with a fairly recent LLVM from git
> tree (6.0.0git-2d810c2).
> 
> Looks like the llvm error is triggered when section name and
> the function name for XDP prog is the same. Changing either the
> function or the section name right above resolves the issue. If
> such error didn't trigger on older versions, people could be
> using such naming scheme as done here, so seems to me like a
> regression on LLVM side we might need to look at ...
Agreed.
> 
> In any case, patch here is fine, thanks!

Thank you.