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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id DDD0CC5478C for ; Mon, 26 Feb 2024 16:09:44 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1redWA-0006YN-LM; Mon, 26 Feb 2024 11:07:50 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1redVo-0006Kh-L8; Mon, 26 Feb 2024 11:07:29 -0500 Received: from frasgout.his.huawei.com ([185.176.79.56]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1redVg-0005xM-OL; Mon, 26 Feb 2024 11:07:26 -0500 Received: from mail.maildlp.com (unknown [172.18.186.231]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Tk54l1vTTz67PjK; Tue, 27 Feb 2024 00:03:19 +0800 (CST) Received: from lhrpeml500005.china.huawei.com (unknown [7.191.163.240]) by mail.maildlp.com (Postfix) with ESMTPS id 9CDB7140A35; Tue, 27 Feb 2024 00:07:02 +0800 (CST) Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.35; Mon, 26 Feb 2024 16:07:02 +0000 Date: Mon, 26 Feb 2024 16:07:00 +0000 To: Zhao Liu CC: Fan Ni , Laurent Vivier , Alistair Francis , "Edgar E . Iglesias" , Peter Maydell , "Michael S . Tsirkin" , Marcel Apfelbaum , Alex Williamson , =?ISO-8859-1?Q?C=E9dric?= Le Goater , Philippe =?ISO-8859-1?Q?Mathieu-Daud=E9?= , Markus Armbruster , Paolo Bonzini , Michael Tokarev , , , , Zhao Liu Subject: Re: [PATCH v2 1/7] hw/cxl/cxl-host: Fix missing ERRP_GUARD() in cxl_fixed_memory_window_config() Message-ID: <20240226160700.00007286@Huawei.com> In-Reply-To: <20240223085653.1255438-2-zhao1.liu@linux.intel.com> References: <20240223085653.1255438-1-zhao1.liu@linux.intel.com> <20240223085653.1255438-2-zhao1.liu@linux.intel.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.227.76] X-ClientProxiedBy: lhrpeml500002.china.huawei.com (7.191.160.78) To lhrpeml500005.china.huawei.com (7.191.163.240) Received-SPF: pass client-ip=185.176.79.56; envelope-from=jonathan.cameron@huawei.com; helo=frasgout.his.huawei.com X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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: , Reply-to: Jonathan Cameron From: Jonathan Cameron via Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Fri, 23 Feb 2024 16:56:47 +0800 Zhao Liu wrote: > From: Zhao Liu > > As the comment in qapi/error, dereferencing @errp requires > ERRP_GUARD(): > > * = Why, when and how to use ERRP_GUARD() = > * > * Without ERRP_GUARD(), use of the @errp parameter is restricted: > * - It must not be dereferenced, because it may be null. > ... > * ERRP_GUARD() lifts these restrictions. > * > * To use ERRP_GUARD(), add it right at the beginning of the function. > * @errp can then be used without worrying about the argument being > * NULL or &error_fatal. > * > * Using it when it's not needed is safe, but please avoid cluttering > * the source with useless code. > > But in cxl_fixed_memory_window_config(), @errp is dereferenced in 2 > places without ERRP_GUARD(): > > fw->enc_int_ways = cxl_interleave_ways_enc(fw->num_targets, errp); > if (*errp) { > return; > } > > and > > fw->enc_int_gran = > cxl_interleave_granularity_enc(object->interleave_granularity, > errp); > if (*errp) { > return; > } > > For the above 2 places, we check "*errp", because neither function > returns a suitable error code. And since machine_set_cfmw() - the caller > of cxl_fixed_memory_window_config() - doesn't get the NULL @errp > parameter as the "set" method of object property, > cxl_fixed_memory_window_config() hasn't triggered the bug that > dereferencing the NULL @errp. > > To follow the requirement of @errp, add missing ERRP_GUARD() in > cxl_fixed_memory_window_config(). > > Suggested-by: Markus Armbruster > Signed-off-by: Zhao Liu > Reviewed-by: Markus Armbruster Acked-by: Jonathan Cameron > --- > Suggested by credit: > Markus: Referred his explanation about ERRP_GUARD(). > --- > v2: > * Add the @errp dereference code in commit message to make review > easier. (Markus) > --- > hw/cxl/cxl-host.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/hw/cxl/cxl-host.c b/hw/cxl/cxl-host.c > index 2aa776c79c74..c5f5fcfd64d0 100644 > --- a/hw/cxl/cxl-host.c > +++ b/hw/cxl/cxl-host.c > @@ -26,6 +26,7 @@ static void cxl_fixed_memory_window_config(CXLState *cxl_state, > CXLFixedMemoryWindowOptions *object, > Error **errp) > { > + ERRP_GUARD(); > g_autofree CXLFixedWindow *fw = g_malloc0(sizeof(*fw)); > strList *target; > int i;