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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 BFE88C83003 for ; Wed, 29 Apr 2020 13:16:42 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8773821775 for ; Wed, 29 Apr 2020 13:16:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Vro34TU4" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8773821775 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:34536 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jTmZt-00072p-Oi for qemu-devel@archiver.kernel.org; Wed, 29 Apr 2020 09:16:41 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:35500) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jTmYL-0005m5-CJ for qemu-devel@nongnu.org; Wed, 29 Apr 2020 09:15:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.90_1) (envelope-from ) id 1jTmYK-0002dz-QC for qemu-devel@nongnu.org; Wed, 29 Apr 2020 09:15:05 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:56313 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jTmYK-0002dg-DF for qemu-devel@nongnu.org; Wed, 29 Apr 2020 09:15:04 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1588166103; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=uHJ5OrObd5lWEoAZ5X+WaObvzESGCY7VL90bFN2zKsw=; b=Vro34TU4SH0JxXk1pne5JxcBg0FCFK2BiJljCBZDY71djqniVgPSbpH5vTzx6PR6ffC5y9 oPAl/dE2XDP+Tx6Alfk3tg9EQYvCTnwhvM9F4MQhbeyrNGBDmOsS1tlBdzzMDe5L+3hWJT qkAGF7uviC51ZwarQ+t1PYA5duVo8A4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-54-qfokVEuvP5qUJqWg_Mtv3A-1; Wed, 29 Apr 2020 09:14:50 -0400 X-MC-Unique: qfokVEuvP5qUJqWg_Mtv3A-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2BA938014D5; Wed, 29 Apr 2020 13:14:49 +0000 (UTC) Received: from [10.10.116.80] (ovpn-116-80.rdu2.redhat.com [10.10.116.80]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9D1955C1BE; Wed, 29 Apr 2020 13:14:48 +0000 (UTC) Subject: Re: [PATCH 0/9] More truncate improvements To: qemu-devel@nongnu.org References: <158812705840.2837.3534564330691034557@39012742ff91> From: Eric Blake Organization: Red Hat, Inc. Message-ID: Date: Wed, 29 Apr 2020 08:14:47 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <158812705840.2837.3534564330691034557@39012742ff91> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=205.139.110.120; envelope-from=eblake@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/04/29 01:42:37 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] X-Received-From: 205.139.110.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, qemu-block@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 4/28/20 9:24 PM, no-reply@patchew.org wrote: > Patchew URL: https://patchew.org/QEMU/20200428202905.770727-1-eblake@redhat.com/ > > /tmp/qemu-test/src/block/parallels.c: In function 'parallels_co_writev': > /tmp/qemu-test/src/block/parallels.c:218:12: error: 'ret' may be used uninitialized in this function [-Werror=maybe-uninitialized] > if (ret < 0) { > ^ > /tmp/qemu-test/src/block/parallels.c:169:9: note: 'ret' was declared here > int ret; > ^ False positive: the code is roughly: int ret; if (cond1) { ret = ...; } if (cond2) { ret = ...; } if (ret < 0) but the compiler can't prove that cond1 + cond2 covers all possibilities. The obvious fix is to initialize ret; squash this into 7/9: diff --git i/block/parallels.c w/block/parallels.c index eb6c6c01b998..e7717c508e62 100644 --- i/block/parallels.c +++ w/block/parallels.c @@ -166,7 +166,7 @@ static int64_t block_status(BDRVParallelsState *s, int64_t sector_num, static int64_t allocate_clusters(BlockDriverState *bs, int64_t sector_num, int nb_sectors, int *pnum) { - int ret; + int ret = 0; BDRVParallelsState *s = bs->opaque; int64_t pos, space, idx, to_allocate, i, len; -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org