From mboxrd@z Thu Jan  1 00:00:00 1970
From: Thomas Monjalon <thomas.monjalon@6wind.com>
Subject: Re: [PATCH v2] mk: fix objects/library order when linking
Date: Fri, 04 Dec 2015 19:43:30 +0100
Message-ID: <2454571.EZpaR9m7WP@xps13>
References: <1449239893-4012-1-git-send-email-david.marchand@6wind.com>
 <1449249063-9792-1-git-send-email-david.marchand@6wind.com>
 <20151204173114.GH5048@6wind.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7Bit
Cc: dev@dpdk.org
To: David Marchand <david.marchand@6wind.com>
Return-path: <dev-bounces@dpdk.org>
Received: from mail-wm0-f47.google.com (mail-wm0-f47.google.com [74.125.82.47])
 by dpdk.org (Postfix) with ESMTP id BE72C9221
 for <dev@dpdk.org>; Fri,  4 Dec 2015 19:44:40 +0100 (CET)
Received: by wmww144 with SMTP id w144so76378643wmw.0
 for <dev@dpdk.org>; Fri, 04 Dec 2015 10:44:40 -0800 (PST)
In-Reply-To: <20151204173114.GH5048@6wind.com>
List-Id: patches and discussions about DPDK <dev.dpdk.org>
List-Unsubscribe: <http://dpdk.org/ml/options/dev>,
 <mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://dpdk.org/ml/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <http://dpdk.org/ml/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
Errors-To: dev-bounces@dpdk.org
Sender: "dev" <dev-bounces@dpdk.org>

2015-12-04 18:31, Adrien Mazarguil:
> On Fri, Dec 04, 2015 at 06:11:03PM +0100, David Marchand wrote:
> > The initial problem has been seen while building mlx4 pmd as a shared library
> > on Ubuntu 14.04 (gcc 4.8.4-2ubuntu1~14.04).
> > 
> > Resulting .so will lack the DT_NEEDED entry for libibverbs:
> > 
> > marchand@ubuntu1404:~/dpdk$ ldd ./build/lib/librte_pmd_mlx4.so
> > 	linux-vdso.so.1 =>  (0x00007fff87ebb000)
> > 	libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f2ced21a000)
> > 	/lib64/ld-linux-x86-64.so.2 (0x00007f2ced821000)
> > 
> > And trying to load it in testpmd triggers this error:
> > 
> > [...]
> > EAL: librte_pmd_mlx4.so: undefined symbol: ibv_query_port
> > [...]
> > 
> > After some strace, the problem comes from the --as-needed option passed to the
> > linker.
> > 
> > It is safer to specify libraries we depend on after the objects we are linking
> > into a shared library, especially when the linker is invoked with options like
> > --as-needed.
> > 
> > Fixes: bef06a8a0655 ("mk: set library dependencies in shared object file")
> > 
> > Signed-off-by: David Marchand <david.marchand@6wind.com>
> > ---
> > 
> > Changes since v1:
> > - added some details in commitlog since Thomas does not like "safer"
> >   argument :-)

Yes, that's better justified with these details :)

> Obvious issue that did not show up in our tests under Debian.
> 
> Acked-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>

Applied, thanks