From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5B73CC282CC for ; Tue, 5 Feb 2019 18:43:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 32C7B217F9 for ; Tue, 5 Feb 2019 18:43:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730510AbfBESnC (ORCPT ); Tue, 5 Feb 2019 13:43:02 -0500 Received: from smtprelay0223.hostedemail.com ([216.40.44.223]:35215 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726731AbfBESm7 (ORCPT ); Tue, 5 Feb 2019 13:42:59 -0500 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay03.hostedemail.com (Postfix) with ESMTP id A2CAE83777E3; Tue, 5 Feb 2019 18:42:56 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: team78_198465e6d7129 X-Filterd-Recvd-Size: 1752 Received: from XPS-9350.home (unknown [47.151.153.53]) (Authenticated sender: joe@perches.com) by omf11.hostedemail.com (Postfix) with ESMTPA; Tue, 5 Feb 2019 18:42:55 +0000 (UTC) Message-ID: <8553086eaec167846992f1cff12aa388cee81767.camel@perches.com> Subject: Re: [PATCH v2 2/2] r8169: Avoid pointer aliasing From: Joe Perches To: David Miller , thierry.reding@gmail.com Cc: hkallweit1@gmail.com, andrew@lunn.ch, nic_swsd@realtek.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Date: Tue, 05 Feb 2019 10:42:54 -0800 In-Reply-To: <20190204.192040.1074738183781998611.davem@davemloft.net> References: <20190204164213.30727-1-thierry.reding@gmail.com> <20190204164213.30727-2-thierry.reding@gmail.com> <20190204.192040.1074738183781998611.davem@davemloft.net> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.30.1-1build1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2019-02-04 at 19:20 -0800, David Miller wrote: > From: Thierry Reding > Date: Mon, 4 Feb 2019 17:42:13 +0100 > > > @@ -7316,7 +7325,7 @@ static int rtl_get_ether_clk(struct rtl8169_private *tp) > > static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent) > > { > > const struct rtl_cfg_info *cfg = rtl_cfg_infos + ent->driver_data; > > - u8 mac_addr[ETH_ALEN] __aligned(4) = {}; > > + u8 mac_addr[ETH_ALEN] = {}; > > struct rtl8169_private *tp; > > I agree with Heiner, you have to provide at least 2 byte alignment for this > buffer due to the reasons he stated. It's declared after a pointer so it is already is 2 byte aligned. A lot of drivers wouldn't work otherwise.