From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <pshelar@nicira.com>
Received: from na3sys009aog131.obsmtp.com (na3sys009aog131.obsmtp.com
 [74.125.149.247]) by dpdk.org (Postfix) with SMTP id 080539AA2
 for <dev@dpdk.org>; Wed, 25 Mar 2015 20:46:00 +0100 (CET)
Received: from mail-ie0-f179.google.com ([209.85.223.179]) (using TLSv1) by
 na3sys009aob131.postini.com ([74.125.148.12]) with SMTP
 ID DSNKVRMQeOtlUtJwz2Aue7Ew9ku4GHKLkNa+@postini.com;
 Wed, 25 Mar 2015 12:46:01 PDT
Received: by mail-ie0-f179.google.com with SMTP id vj10so30519132iec.0
 for <dev@dpdk.org>; Wed, 25 Mar 2015 12:46:00 -0700 (PDT)
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
 d=1e100.net; s=20130820;
 h=x-gm-message-state:mime-version:in-reply-to:references:date
 :message-id:subject:from:to:cc:content-type;
 bh=vvJx1L/7jh8t7qlJs3gg56JxxfG6X25YEYa7qS1CpwU=;
 b=RCGFs6+gdAVNr5/R0lz7SpTfcurBPwnfjaYuT1LT9l/JgPeIMTv7FgDtSI/zRwVHW1
 dbF8IUNGLz6q3F8Y2bCJz52D98WNlAejYwHChJtTAj2F2LINXzKGtW+2Zr6f7N3aFpfd
 2D+P+boe3fHZUClByaJN2EnWvHiW+ZpfFVZtrnWOu9eAcRq8eiZv3XydQQjVdeOxvYOp
 igNKNfMEvjNILnGgS2/7YuXiBpMKH9A8uTaGBwqlvd9ATJ+8hs55Q50nyRAspsjFosdK
 ZjTUNUWK4ttUTlsHPKL+VQlUcZc02QOXpMXZ3eC2x+9YBxn/AkPR5d6f1OoT423I5YUM
 6oJg==
X-Gm-Message-State: ALoCoQno0dbzAIreWyBE6knA5nQpvgh9LPfSaUtnYtF6B/3T99kfb5SgQtxXiEuNGfLS4Iqkt32Un32uB27AvOHubPHlBDxAkUyyGMSaNl8kPvu0pXWpScIXj/vKHGyCAUkKKmwxSnZLPMmccGnjmx/UXHLUmPG0VQ==
X-Received: by 10.42.193.69 with SMTP id dt5mr1558979icb.42.1427312760021;
 Wed, 25 Mar 2015 12:46:00 -0700 (PDT)
MIME-Version: 1.0
X-Received: by 10.42.193.69 with SMTP id dt5mr1558968icb.42.1427312759922;
 Wed, 25 Mar 2015 12:45:59 -0700 (PDT)
Received: by 10.107.136.31 with HTTP; Wed, 25 Mar 2015 12:45:59 -0700 (PDT)
In-Reply-To: <55130BA5.4080209@linaro.org>
References: <55130BA5.4080209@linaro.org>
Date: Wed, 25 Mar 2015 12:45:59 -0700
Message-ID: <CALnjE+qu4r2d1C33tnUwBvotmCf7H26K2vVrqwteBHjyArF0Lw@mail.gmail.com>
From: Pravin Shelar <pshelar@nicira.com>
To: Zoltan Kiss <zoltan.kiss@linaro.org>
Content-Type: text/plain; charset=UTF-8
Cc: "dev@dpdk.org" <dev@dpdk.org>, "dev@openvswitch.org" <dev@openvswitch.org>
Subject: Re: [dpdk-dev] [ovs-dev] ovs-dpdk: ofpbuf reinitialization
X-BeenThere: dev@dpdk.org
X-Mailman-Version: 2.1.15
Precedence: list
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: Wed, 25 Mar 2015 19:46:01 -0000

On Wed, Mar 25, 2015 at 12:25 PM, Zoltan Kiss <zoltan.kiss@linaro.org> wrote:
> Hi,
>
> Looking around in the DPDK code I've found that it only initializes the
> packet metadata (whih contains the struct ofpbuf belonging to the packet)
> during setup, as the packet initializer of rte_mempool_create.
> That means that every time a packet buffer is released back by OVS to the
> buffer pool, it retains ofpbuf state, and it doesn't change when the poll
> mode driver use the buffer again to store a new packet. "source" and
> "allocated members of ofpbuf shouldn't change, but frame, l2_pad_size and
> the offsets does at various places. Even though I couldn't establish an
> error scenario yet, I think it's quite dangerous to leave the packet to
> inherit the previous packet's ofpbuf.
> Or am I missing some place where this piece is reinitialized?
>

l2_pad and offsets are initialized during flow extraction. These
fields should not be accessed before this step.