From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752257AbeB1JF2 convert rfc822-to-8bit (ORCPT ); Wed, 28 Feb 2018 04:05:28 -0500 Received: from smtp-out6.electric.net ([192.162.217.181]:54288 "EHLO smtp-out6.electric.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751877AbeB1JFZ (ORCPT ); Wed, 28 Feb 2018 04:05:25 -0500 From: David Laight To: "'Stefano Stabellini'" , "jgross@suse.com" , "boris.ostrovsky@oracle.com" CC: "xen-devel@lists.xenproject.org" , "linux-kernel@vger.kernel.org" Subject: RE: [PATCH] pvcalls-front: 64-bit align flags Thread-Topic: [PATCH] pvcalls-front: 64-bit align flags Thread-Index: AQHTsAT/Cr5qqOD/wkWB1uwC1GV/XKO5hi7g Date: Wed, 28 Feb 2018 09:06:17 +0000 Message-ID: <139554adced44c5ea5aa4fab4f0ca8a0@AcuMS.aculab.com> References: In-Reply-To: Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.33] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 X-Outbound-IP: 156.67.243.126 X-Env-From: David.Laight@ACULAB.COM X-Proto: esmtps X-Revdns: X-HELO: AcuMS.aculab.com X-TLS: TLSv1.2:ECDHE-RSA-AES256-SHA384:256 X-Authenticated_ID: X-PolicySMART: 3396946, 3397078 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Stefano Stabellini > Sent: 27 February 2018 19:55 > > We are using test_and_* operations on the status and flag fields of > struct sock_mapping. However, these functions require the operand to be > 64-bit aligned on arm64. Currently, only status is 64-bit aligned. That sounds like a big accident just waiting to happen... If the operand is required to be 64bit aligned why isn't it a type that requires 64bit alignment? > Make flags 64-bit aligned by introducing an explicit padding field. At some point such padding will always go wrong... David