From nobody Tue May 7 02:10:59 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=pass(p=quarantine dis=none) header.from=suse.com ARC-Seal: i=1; a=rsa-sha256; t=1615555722; cv=none; d=zohomail.com; s=zohoarc; b=hyhIVadnxoV1eRey56DIyc60DF5NPY20WEcLlb/KkM/CdvsiLCH/zlxBqlX50pS+6EJn0E9yBiTDrEMgheDf1Z9dwe9XWtB8g83j96FDjyqUchzlZAzkcuWtHn0ptmK6eKgm489KGXE9zUGjn1zsoodRHrhc6WMlcxPnNrqHGek= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1615555722; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:List-Subscribe:List-Post:List-Id:List-Help:List-Unsubscribe:MIME-Version:Message-ID:Sender:Subject:To; bh=SB6cjRcfANDSZoA5AjSpD/ZyaGqTkyrX+8xNZEZp/CM=; b=gV8ABMB3D/Vib0Rm2bLkpJHP45lg4bGS6I1YT4JYsyBgnAiFNZ5tDuIFzcOoRi/LcFvCkfAgbzqh9dTxICnMuegYZ2Md0Ce9bQYg3WekGR1YSHwr8bYjnBd4A6D1Qdp4mFiZKHroyODHAnWuioXv/7m3sy6O+N2EK3eH7KnhtI0= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org; dmarc=pass header.from= (p=quarantine dis=none) header.from= Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 1615555722460165.93455295632987; Fri, 12 Mar 2021 05:28:42 -0800 (PST) Received: from list by lists.xenproject.org with outflank-mailman.97115.184295 (Exim 4.92) (envelope-from ) id 1lKhpv-0002UR-LG; Fri, 12 Mar 2021 13:28:15 +0000 Received: by outflank-mailman (output) from mailman id 97115.184295; Fri, 12 Mar 2021 13:28:15 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lKhpv-0002UK-I9; Fri, 12 Mar 2021 13:28:15 +0000 Received: by outflank-mailman (input) for mailman id 97115; Fri, 12 Mar 2021 13:28:14 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lKhpu-0002UF-Dn for xen-devel@lists.xenproject.org; Fri, 12 Mar 2021 13:28:14 +0000 Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 6a1ae1bb-2291-437d-8b45-ec1334cf1d9b; Fri, 12 Mar 2021 13:28:13 +0000 (UTC) Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id D962AAF4D; Fri, 12 Mar 2021 13:28:12 +0000 (UTC) X-Outflank-Mailman: Message body and most headers restored to incoming version X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 6a1ae1bb-2291-437d-8b45-ec1334cf1d9b X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1615555693; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=SB6cjRcfANDSZoA5AjSpD/ZyaGqTkyrX+8xNZEZp/CM=; b=dzGZOfmSWx55h8P8MVGUKvweRhEXiqvHPGlHGKhMJg2894UaU1kESPpsbXSGurTILUJc8K eaFV3xpKnlPZZydrb5jT515fcXyWvyJPwrUWLbn8ohfmu3u7Jxqf4IJsYj6o6jXECO9maH DwGpk0QBKoJI9zaZoAqML4wNMziW/oY= From: Jan Beulich Subject: [PATCH v2][4.15] gnttab: work around "may be used uninitialized" warning To: "xen-devel@lists.xenproject.org" Cc: Andrew Cooper , George Dunlap , Ian Jackson , Julien Grall , Stefano Stabellini , Wei Liu Message-ID: <099e79c0-6443-2199-1242-3cfc4d93c367@suse.com> Date: Fri, 12 Mar 2021 14:28:13 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 Content-Language: en-US Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: pass (identity @suse.com) Content-Type: text/plain; charset="utf-8" Sadly I was wrong to suggest dropping vaddrs' initializer during review of v2 of the patch introducing this code. gcc 4.3 can't cope. Fixes: 52531c734ea1 ("xen/gnttab: Rework resource acquisition") Signed-off-by: Jan Beulich Acked-by: Andrew Cooper --- v2: Re-insert the other half of what Andrew had in his original patch. --- a/xen/common/grant_table.c +++ b/xen/common/grant_table.c @@ -4026,7 +4026,7 @@ int gnttab_acquire_resource( struct grant_table *gt =3D d->grant_table; unsigned int i, final_frame; mfn_t tmp; - void **vaddrs; + void **vaddrs =3D NULL; int rc =3D -EINVAL; =20 if ( !nr_frames ) @@ -4055,6 +4055,17 @@ int gnttab_acquire_resource( break; } =20 + /* + * Some older toolchains can't spot that vaddrs won't remain uninitial= ized + * on non-error paths, and hence it needs setting to NULL at the top o= f the + * function. Leave some runtime safety. + */ + if ( !vaddrs ) + { + ASSERT_UNREACHABLE(); + rc =3D -ENODATA; + } + /* Any errors? Bad id, or from growing the table? */ if ( rc ) goto out;