From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <jt@labs.hpe.com>
Received: from g4t3427.houston.hpe.com (g4t3427.houston.hpe.com
 [15.241.140.73]) by dpdk.org (Postfix) with ESMTP id 16BE82A5E
 for <dev@dpdk.org>; Mon,  3 Oct 2016 18:07:44 +0200 (CEST)
Received: from g4t3433.houston.hpecorp.net (g4t3433.houston.hpecorp.net
 [16.208.49.245])
 by g4t3427.houston.hpe.com (Postfix) with ESMTP id 39BAE5C;
 Mon,  3 Oct 2016 16:07:43 +0000 (UTC)
Received: from postal.labs.hpecorp.net (postal.labs.hpecorp.net [16.111.35.25])
 by g4t3433.houston.hpecorp.net (Postfix) with ESMTP id 1758046;
 Mon,  3 Oct 2016 16:07:42 +0000 (UTC)
Received: from bougret.labs.hpecorp.net (bougret.labs.hpecorp.net
 [16.111.8.16])
 by postal.labs.hpecorp.net (8.14.4/8.14.4/HPL-PA Hub) with ESMTP id
 u93G7gll023912
 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT);
 Mon, 3 Oct 2016 09:07:42 -0700
Received: from jt by bougret.labs.hpecorp.net with local (Exim 4.84_2)
 (envelope-from <jt@labs.hpe.com>)
 id 1br5mI-0006Lv-7G; Mon, 03 Oct 2016 09:07:42 -0700
Date: Mon, 3 Oct 2016 09:07:42 -0700
From: Jean Tourrilhes <jt@labs.hpe.com>
To: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>
Cc: dev@dpdk.org
Message-ID: <20161003160742.GC23662@labs.hpe.com>
References: <20160921211049.GA27472@labs.hpe.com>
 <4a84de40-04b9-da6d-aeb9-ce661a9ebad5@intel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <4a84de40-04b9-da6d-aeb9-ce661a9ebad5@intel.com>
Organisation: HP Labs Palo Alto
Address: HP Labs, MS1184, 1501 Page Mill road, Palo Alto, CA 94304, USA.
E-mail: jean.tourrilhes@hpe.com
User-Agent: Mutt/1.5.23 (2014-03-12)
Subject: Re: [dpdk-dev] [PATCH 1/1 v2] eal: Fix misleading error messages,
 errno can't be trusted.
X-BeenThere: dev@dpdk.org
X-Mailman-Version: 2.1.15
Precedence: list
Reply-To: jean.tourrilhes@hpe.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>
X-List-Received-Date: Mon, 03 Oct 2016 16:07:44 -0000

On Mon, Oct 03, 2016 at 02:25:40PM +0100, Sergio Gonzalez Monroy wrote:
> Hi Jean,
> 
> NIT but any reason you moved the check before closing the file descriptor?
> (not that it matters with current code as we panic anyway)
> 
> Thanks,
> Sergio

	More details, as I admit I was terse
	Running secondary is tricky due to the need to map the memory
region at the right place, which is whatever primary has chosen. If
the base address for primary happens to by already mapped in the
secondary, we will hit precisely this error message (well, in a few
case we might hit the other one). This is why there is already
a comment about ASLR.
	A colleague of mine hit that message and was misled by errno
claiming "permission denied", which sent him down the wrong
track. It's such a common error for secondary that I feel this error
message should be unambiguous and helpful.
	Regards,

	Jean