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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 17894C433F5 for ; Tue, 16 Nov 2021 16:56:11 +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 AB7AF61407 for ; Tue, 16 Nov 2021 16:56:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org AB7AF61407 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:43476 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mn1kf-000404-Qp for qemu-devel@archiver.kernel.org; Tue, 16 Nov 2021 11:56:09 -0500 Received: from eggs.gnu.org ([209.51.188.92]:60170) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mn1iv-0002YN-Lj for qemu-devel@nongnu.org; Tue, 16 Nov 2021 11:54:22 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:41862) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mn1it-0000C4-CS for qemu-devel@nongnu.org; Tue, 16 Nov 2021 11:54:20 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1637081658; 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=Ek/TzNoMONBYhBknQW252CkK7d/nYr+xJiTCHhn6KJk=; b=ViIGPpNQ8+OD8qUwUABJGi+KHnmzuSmJ6pkXB1OWUcqWJ5rHyussuB8IXZ/xeL/bptZQx9 dPrH30zPqGjvtdN10UeEqD4OhgSkBYXhDU91bLBlF1upGpgV1ePwFPuNOg4+4Ke3rSGQmR iSHD0cRCmI+JLdaJLK8dIV/+1I3O3L0= 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-455-wIpkmrphNSilU0Da0iDZ5g-1; Tue, 16 Nov 2021 11:54:16 -0500 X-MC-Unique: wIpkmrphNSilU0Da0iDZ5g-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7499E1922960; Tue, 16 Nov 2021 16:54:15 +0000 (UTC) Received: from blue.redhat.com (ovpn-114-146.phx2.redhat.com [10.3.114.146]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2998E1981F; Tue, 16 Nov 2021 16:54:14 +0000 (UTC) From: Eric Blake To: qemu-devel@nongnu.org Subject: [PULL 1/2] nbd/server: Silence clang sanitizer warning Date: Tue, 16 Nov 2021 10:54:07 -0600 Message-Id: <20211116165408.751417-2-eblake@redhat.com> In-Reply-To: <20211116165408.751417-1-eblake@redhat.com> References: <20211116165408.751417-1-eblake@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eblake@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.697, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , Vladimir Sementsov-Ogievskiy , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , "open list:Network Block Dev..." Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" clang's sanitizer is picky: memset(NULL, x, 0) is technically undefined behavior, even though no sane implementation of memset() deferences the NULL. Caught by the nbd-qemu-allocation iotest. The alternative to checking before each memset is to instead force an allocation of 1 element instead of g_new0(type, 0)'s behavior of returning NULL for a 0-length array. Reported-by: Peter Maydell Fixes: 3b1f244c59 (nbd: Allow export of multiple bitmaps for one device) Signed-off-by: Eric Blake Message-Id: <20211115223943.626416-1-eblake@redhat.com> Reviewed-by: Philippe Mathieu-Daudé --- nbd/server.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/nbd/server.c b/nbd/server.c index 6d03e8a4b436..d9164ee6d0da 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -1,5 +1,5 @@ /* - * Copyright (C) 2016-2020 Red Hat, Inc. + * Copyright (C) 2016-2021 Red Hat, Inc. * Copyright (C) 2005 Anthony Liguori * * Network Block Device Server Side @@ -879,7 +879,9 @@ static bool nbd_meta_qemu_query(NBDClient *client, NBDExportMetaContexts *meta, if (!*query) { if (client->opt == NBD_OPT_LIST_META_CONTEXT) { meta->allocation_depth = meta->exp->allocation_depth; - memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps); + if (meta->exp->nr_export_bitmaps) { + memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps); + } } trace_nbd_negotiate_meta_query_parse("empty"); return true; @@ -894,7 +896,8 @@ static bool nbd_meta_qemu_query(NBDClient *client, NBDExportMetaContexts *meta, if (nbd_strshift(&query, "dirty-bitmap:")) { trace_nbd_negotiate_meta_query_parse("dirty-bitmap:"); if (!*query) { - if (client->opt == NBD_OPT_LIST_META_CONTEXT) { + if (client->opt == NBD_OPT_LIST_META_CONTEXT && + meta->exp->nr_export_bitmaps) { memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps); } trace_nbd_negotiate_meta_query_parse("empty"); @@ -1024,7 +1027,9 @@ static int nbd_negotiate_meta_queries(NBDClient *client, /* enable all known contexts */ meta->base_allocation = true; meta->allocation_depth = meta->exp->allocation_depth; - memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps); + if (meta->exp->nr_export_bitmaps) { + memset(meta->bitmaps, 1, meta->exp->nr_export_bitmaps); + } } else { for (i = 0; i < nb_queries; ++i) { ret = nbd_negotiate_meta_query(client, meta, errp); -- 2.33.1