From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:50040) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hLliu-0004Kj-80 for qemu-devel@nongnu.org; Wed, 01 May 2019 05:40:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hLlir-0005Y2-6k for qemu-devel@nongnu.org; Wed, 01 May 2019 05:40:20 -0400 Date: Wed, 1 May 2019 10:40:06 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Message-ID: <20190501094006.GN29808@redhat.com> Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v2 3/5] hw/usb/dev-mtp: Fix GCC 9 build warning List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alistair Francis Cc: "qemu-devel@nongnu.org" , "alistair23@gmail.com" , "kraxel@redhat.com" , "riku.voipio@iki.fi" , "laurent@vivier.eu" , "qemu-trivial@nongnu.org" On Tue, Apr 30, 2019 at 11:28:41PM +0000, Alistair Francis wrote: > Fix this warning with GCC 9 on Fedora 30: > hw/usb/dev-mtp.c:1715:36: error: taking address of packed member of =E2= =80=98struct =E2=80=99 may result in an unaligned pointer valu= e [-Werror=3Daddress-of-packed-member] > 1715 | dataset->filename); > | ~~~~~~~^~~~~~~~~~ >=20 > Signed-off-by: Alistair Francis > --- > hw/usb/dev-mtp.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) >=20 > diff --git a/hw/usb/dev-mtp.c b/hw/usb/dev-mtp.c > index 99548b012d..8233beacab 100644 > --- a/hw/usb/dev-mtp.c > +++ b/hw/usb/dev-mtp.c > @@ -1711,9 +1711,22 @@ static void usb_mtp_write_metadata(MTPState *s, = uint64_t dlen) > assert(!s->write_pending); > assert(p !=3D NULL); > =20 > +/* > + * We are about to access a packed struct. We are confident that the p= ointer > + * address won't be unaligned, so we ignore GCC warnings. > + */ The data is mis-aligned as we're accessing an int16 array that is immediately following an int8 field in a packed struct This problem is fixed by the following series which Gerd has in the USB queue: https://lists.gnu.org/archive/html/qemu-devel/2019-04/msg02524.html > +#if defined(CONFIG_PRAGMA_DIAGNOSTIC_AVAILABLE) && QEMU_GNUC_PREREQ(9,= 0) > +#pragma GCC diagnostic push > +#pragma GCC diagnostic ignored "-Waddress-of-packed-member" > +#endif > + > filename =3D utf16_to_str(MIN(dataset->length, filename_chars), > dataset->filename); > =20 > +#if defined(CONFIG_PRAGMA_DIAGNOSTIC_AVAILABLE) && QEMU_GNUC_PREREQ(9,= 0) > +#pragma GCC diagnostic pop > +#endif > + > if (strchr(filename, '/')) { > usb_mtp_queue_result(s, RES_PARAMETER_NOT_SUPPORTED, d->trans, > 0, 0, 0, 0); Regards, Daniel --=20 |: https://berrange.com -o- https://www.flickr.com/photos/dberran= ge :| |: https://libvirt.org -o- https://fstop138.berrange.c= om :| |: https://entangle-photo.org -o- https://www.instagram.com/dberran= ge :| 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=-8.3 required=3.0 tests=FROM_EXCESS_BASE64, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT 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 523C8C43219 for ; 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Wed, 01 May 2019 05:40:20 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47692) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hLlir-0005XW-1Y; Wed, 01 May 2019 05:40:17 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 8139A3086237; Wed, 1 May 2019 09:40:15 +0000 (UTC) Received: from redhat.com (ovpn-112-28.ams2.redhat.com [10.36.112.28]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0DDE517D7A; Wed, 1 May 2019 09:40:09 +0000 (UTC) Date: Wed, 1 May 2019 10:40:06 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Alistair Francis Message-ID: <20190501094006.GN29808@redhat.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.3 (2019-02-01) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.42]); Wed, 01 May 2019 09:40:15 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH v2 3/5] hw/usb/dev-mtp: Fix GCC 9 build warning 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: "qemu-trivial@nongnu.org" , "riku.voipio@iki.fi" , "laurent@vivier.eu" , "qemu-devel@nongnu.org" , "kraxel@redhat.com" , "alistair23@gmail.com" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Message-ID: <20190501094006.mgQWp8H2Nj4EcLWreLZOU68bVhf48wfR3jeI-98l5qI@z> On Tue, Apr 30, 2019 at 11:28:41PM +0000, Alistair Francis wrote: > Fix this warning with GCC 9 on Fedora 30: > hw/usb/dev-mtp.c:1715:36: error: taking address of packed member of =E2= =80=98struct =E2=80=99 may result in an unaligned pointer valu= e [-Werror=3Daddress-of-packed-member] > 1715 | dataset->filename); > | ~~~~~~~^~~~~~~~~~ >=20 > Signed-off-by: Alistair Francis > --- > hw/usb/dev-mtp.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) >=20 > diff --git a/hw/usb/dev-mtp.c b/hw/usb/dev-mtp.c > index 99548b012d..8233beacab 100644 > --- a/hw/usb/dev-mtp.c > +++ b/hw/usb/dev-mtp.c > @@ -1711,9 +1711,22 @@ static void usb_mtp_write_metadata(MTPState *s, = uint64_t dlen) > assert(!s->write_pending); > assert(p !=3D NULL); > =20 > +/* > + * We are about to access a packed struct. We are confident that the p= ointer > + * address won't be unaligned, so we ignore GCC warnings. > + */ The data is mis-aligned as we're accessing an int16 array that is immediately following an int8 field in a packed struct This problem is fixed by the following series which Gerd has in the USB queue: https://lists.gnu.org/archive/html/qemu-devel/2019-04/msg02524.html > +#if defined(CONFIG_PRAGMA_DIAGNOSTIC_AVAILABLE) && QEMU_GNUC_PREREQ(9,= 0) > +#pragma GCC diagnostic push > +#pragma GCC diagnostic ignored "-Waddress-of-packed-member" > +#endif > + > filename =3D utf16_to_str(MIN(dataset->length, filename_chars), > dataset->filename); > =20 > +#if defined(CONFIG_PRAGMA_DIAGNOSTIC_AVAILABLE) && QEMU_GNUC_PREREQ(9,= 0) > +#pragma GCC diagnostic pop > +#endif > + > if (strchr(filename, '/')) { > usb_mtp_queue_result(s, RES_PARAMETER_NOT_SUPPORTED, d->trans, > 0, 0, 0, 0); Regards, Daniel --=20 |: https://berrange.com -o- https://www.flickr.com/photos/dberran= ge :| |: https://libvirt.org -o- https://fstop138.berrange.c= om :| |: https://entangle-photo.org -o- https://www.instagram.com/dberran= ge :|