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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <59A7F658.4020606@iogearbox.net>
Date:   Thu, 31 Aug 2017 13:43:20 +0200
From:   Daniel Borkmann <daniel@...earbox.net>
To:     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 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?
>
> 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 ...

In any case, patch here is fine, thanks!