From nobody Sun Apr 28 07:35:17 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1529674049571854.3933905290095; Fri, 22 Jun 2018 06:27:29 -0700 (PDT) Received: from localhost ([::1]:33876 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fWM64-0002bX-Mi for importer@patchew.org; Fri, 22 Jun 2018 09:27:28 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50292) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fWLe1-0004Nz-9G for qemu-devel@nongnu.org; Fri, 22 Jun 2018 08:58:30 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fWLe0-00065a-Bo for qemu-devel@nongnu.org; Fri, 22 Jun 2018 08:58:29 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:58146 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fWLdu-00063O-4u; Fri, 22 Jun 2018 08:58:22 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9D43F68803; Fri, 22 Jun 2018 12:58:21 +0000 (UTC) Received: from red.redhat.com (ovpn-120-169.rdu2.redhat.com [10.10.120.169]) by smtp.corp.redhat.com (Postfix) with ESMTP id 15B502156700; Fri, 22 Jun 2018 12:58:21 +0000 (UTC) From: Eric Blake To: qemu-devel@nongnu.org Date: Fri, 22 Jun 2018 07:58:14 -0500 Message-Id: <20180622125814.345274-1-eblake@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.1]); Fri, 22 Jun 2018 12:58:21 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.1]); Fri, 22 Jun 2018 12:58:21 +0000 (UTC) for IP:'10.11.54.6' DOMAIN:'int-mx06.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'eblake@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PATCH] nbd/server: Silence gcc false positive 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: peter.maydell@linaro.org, "open list:Network Block Dev..." , Paolo Bonzini Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" The code has a while() loop that always initialized 'end', and the loop always executes at least once (as evidenced by the assert() just prior to the loop). But some versions of gcc still complain that 'end' is used uninitialized, so silence them. Signed-off-by: Eric Blake Reviewed-by: Peter Maydell --- Peter, do you want to apply this directly as a build fix, or shall I submit a pull request? nbd/server.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/nbd/server.c b/nbd/server.c index 274604609f4..50ac8bfafc6 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -1937,7 +1937,7 @@ static unsigned int bitmap_to_extents(BdrvDirtyBitmap= *bitmap, uint64_t offset, unsigned int nb_extents, bool dont_fragment) { - uint64_t begin =3D offset, end; + uint64_t begin =3D offset, end =3D offset; uint64_t overall_end =3D offset + *length; unsigned int i =3D 0; BdrvDirtyBitmapIter *it; @@ -1977,6 +1977,7 @@ static unsigned int bitmap_to_extents(BdrvDirtyBitmap= *bitmap, uint64_t offset, bdrv_dirty_bitmap_unlock(bitmap); + assert(offset > end); *length =3D end - offset; return i; } --=20 2.14.4