From patchwork Fri Feb 1 16:35:04 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 157301 Delivered-To: patch@linaro.org Received: by 2002:a02:48:0:0:0:0:0 with SMTP id 69csp680352jaa; Fri, 1 Feb 2019 09:03:43 -0800 (PST) X-Google-Smtp-Source: ALg8bN62Rvto9bF4NmwQ9d4uvVhPRupMptDWN50s5Xch6oCBjoyjiY5e7ipB5Uw1Nvi6EKa903py X-Received: by 2002:a81:2209:: with SMTP id i9mr38591135ywi.2.1549040623485; Fri, 01 Feb 2019 09:03:43 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1549040623; cv=none; d=google.com; s=arc-20160816; b=PiOacxkGMkGXVkXThq+/utydsFNUDoKhkmcwZEp8O5ejs6KFfAGs2oVkT0mEUs+hhB 539lBrJB+FGX1DvyGd65M/2KeJlbzm8tBWjO3sThyAy1asTsL0B/QJtNALy1sqRrbpI1 XijsMLcQbpxs4P3DqtLtys8RrOzDBAiK9weY6B/pTva7oe//txvgbpccdegHrgKZVtDh Wc1RGf2wveOvpfnuzyRE2qXPXYG1FYagQrHAaOrTpP+8msdy5JcMBrwhWtZiSIE2Gjj5 /d3D+O2q/BZ+z3qU0LQtMvhnZyyHS2t2s3fbrN6zZ75d7e3gpKnC0LieK4NWm9fpcAdf kx4w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=sender:errors-to:cc:list-subscribe:list-help:list-post:list-archive :list-unsubscribe:list-id:precedence:subject :content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:to:from; bh=LGTXOTjT4lgn9+PyEEIyf/9L3ose16SvxyARTpwcWCo=; b=SvL9dxf/Ne4Ga9apex5+FNqrpvxhGf9bD3ch3kXTVM1JbD/q/sqpLMyTEb42mAleMT d9A1y+MyuhfwTcMYiPB4gvVkEQR7xX16KX+PW1EYuBfFxTS8DL+08lGz1Jn+tzTw5NyP jr92gn6oFNqb+VUeJbcxllVgJUbJGOvt3MgKT1fiX1URBMGTurQnaZwJfbjHK5HIgu8s lwGfYDObg8gcqqsBtUBTp7cbcquO2x5Gpfaktt2Q+9/eXEAc3mKhhOw4vIAxZT6LOk9V tO6BC7C15vbzm8kPrBLaLoxIVrNogxsAXHBykkqaqLeW7sDApWLzGuIJGD9erlUnN9jC rgaQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom="qemu-devel-bounces+patch=linaro.org@nongnu.org"; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org. [209.51.188.17]) by mx.google.com with ESMTPS id d185si4984748ywb.95.2019.02.01.09.03.43 for (version=TLS1 cipher=AES128-SHA bits=128/128); Fri, 01 Feb 2019 09:03:43 -0800 (PST) Received-SPF: pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; Authentication-Results: mx.google.com; spf=pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom="qemu-devel-bounces+patch=linaro.org@nongnu.org"; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from localhost ([127.0.0.1]:58141 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gpcEA-0003LH-Us for patch@linaro.org; Fri, 01 Feb 2019 12:03:43 -0500 Received: from eggs.gnu.org ([209.51.188.92]:39111) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gpbo5-0007nC-Q7 for qemu-devel@nongnu.org; Fri, 01 Feb 2019 11:36:48 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gpbo3-0008W9-Le for qemu-devel@nongnu.org; Fri, 01 Feb 2019 11:36:45 -0500 Received: from mx1.redhat.com ([209.132.183.28]:37631) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gpbnt-000884-4F; Fri, 01 Feb 2019 11:36:33 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C4B1C796E0; Fri, 1 Feb 2019 16:35:50 +0000 (UTC) Received: from localhost.localdomain.com (ovpn-117-95.ams2.redhat.com [10.36.117.95]) by smtp.corp.redhat.com (Postfix) with ESMTP id B2505608C8; Fri, 1 Feb 2019 16:35:49 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Date: Fri, 1 Feb 2019 17:35:04 +0100 Message-Id: <20190201163518.31157-14-kwolf@redhat.com> In-Reply-To: <20190201163518.31157-1-kwolf@redhat.com> References: <20190201163518.31157-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Fri, 01 Feb 2019 16:35:50 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL 13/27] block/vpc: Don't take address of fields in packed structs X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, peter.maydell@linaro.org, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+patch=linaro.org@nongnu.org Sender: "Qemu-devel" From: Peter Maydell Taking the address of a field in a packed struct is a bad idea, because it might not be actually aligned enough for that pointer type (and thus cause a crash on dereference on some host architectures). Newer versions of clang warn about this. Avoid the bug by generating the UUID into a local variable which is definitely safely aligned and then copying it into place. Signed-off-by: Peter Maydell Signed-off-by: Kevin Wolf --- block/vpc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) -- 2.20.1 diff --git a/block/vpc.c b/block/vpc.c index d886465b7e..52ab717642 100644 --- a/block/vpc.c +++ b/block/vpc.c @@ -979,6 +979,7 @@ static int coroutine_fn vpc_co_create(BlockdevCreateOptions *opts, int64_t total_size; int disk_type; int ret = -EIO; + QemuUUID uuid; assert(opts->driver == BLOCKDEV_DRIVER_VPC); vpc_opts = &opts->u.vpc; @@ -1062,7 +1063,8 @@ static int coroutine_fn vpc_co_create(BlockdevCreateOptions *opts, footer->type = cpu_to_be32(disk_type); - qemu_uuid_generate(&footer->uuid); + qemu_uuid_generate(&uuid); + footer->uuid = uuid; footer->checksum = cpu_to_be32(vpc_checksum(buf, HEADER_SIZE));