From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH net 1/2] ptp: check that rsv field is zero in struct
 ptp_sys_offset_extended
Date: Mon, 07 Jan 2019 08:29:38 -0800 (PST)
Message-ID: <20190107.082938.1649593594398135118.davem@davemloft.net>
References: <20181109101449.15398-4-mlichvar@redhat.com>
        <20190107152229.GA17925@asgard.redhat.com>
Mime-Version: 1.0
Content-Type: Text/Plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Cc: mlichvar@redhat.com, netdev@vger.kernel.org,
        richardcochran@gmail.com, jacob.e.keller@intel.com,
        mtosatti@redhat.com
To: esyr@redhat.com
Return-path: <netdev-owner@vger.kernel.org>
Received: from shards.monkeyblade.net ([23.128.96.9]:57808 "EHLO
        shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1727576AbfAGQ3k (ORCPT
        <rfc822;netdev@vger.kernel.org>); Mon, 7 Jan 2019 11:29:40 -0500
In-Reply-To: <20190107152229.GA17925@asgard.redhat.com>
Sender: netdev-owner@vger.kernel.org
List-ID: <netdev.vger.kernel.org>

From: Eugene Syromiatnikov <esyr@redhat.com>
Date: Mon, 7 Jan 2019 16:22:29 +0100

> Otherwise it is impossible to use it for something else, as it will break
> userspace that puts garbage there.
> 
> The same check should be done in other structures, but the fact that
> data in reserved fields is ignored is already part of the kernel ABI.
> 
> Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>

I think the opportunity to enforce this has passed and you will break
userspace by doing this.