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 82C4BC3DA63 for ; Tue, 23 Jul 2024 14:15:28 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sWGHt-0007u6-2Z; Tue, 23 Jul 2024 10:14:45 -0400 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 1sWGHr-0007n5-45 for qemu-devel@nongnu.org; Tue, 23 Jul 2024 10:14:43 -0400 Received: from mgamail.intel.com ([192.198.163.14]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sWGHn-0006mB-CP for qemu-devel@nongnu.org; Tue, 23 Jul 2024 10:14:42 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1721744079; x=1753280079; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=88/ZD+HzKHSRWovuOAAXbLcof1+XgIRS2ZMH1oJpst0=; b=MlNalZaIa22z9TtCeOl/ODN5dZuu9R4DKZka0Hhk8kd063KhkEYBlvAO bQ/KJzupYnYlCoDxdpcAWt8cfhBn1EMNaxvPsRbjuLUJNGsHZd+yr+VeS P9seaOFueKNHG14hWiTek2wxOYyzWUnMP1Sf8PJ+3Xv1qwwGmbeCS9Zd7 jQschqx9xGDdVzrkxA0qFxWJx81WeUghOwzhzplJfSfCCFbUxP63g26Kh Ip+dKu0iIazdy0UrAiIErDSoA5XksGgZHlS02Zut6y/MJrD3iaEQd8S9o YSh/Qh2mOX24jCem/dIl5cRVacNqbatqCxW+PSZcb/cmGZVcBGjQvpIHi g==; X-CSE-ConnectionGUID: miE9RNduRPGAtSJMQk+VOg== X-CSE-MsgGUID: dRMIeNxxRharcD5EtHXf4w== X-IronPort-AV: E=McAfee;i="6700,10204,11142"; a="19555156" X-IronPort-AV: E=Sophos;i="6.09,230,1716274800"; d="scan'208";a="19555156" Received: from orviesa009.jf.intel.com ([10.64.159.149]) by fmvoesa108.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Jul 2024 07:14:27 -0700 X-CSE-ConnectionGUID: arDldOIsSRGrOt3VcX9dCw== X-CSE-MsgGUID: hsd3Aqi6T3mvWggOqjIPXQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.09,230,1716274800"; d="scan'208";a="52267500" Received: from liuzhao-optiplex-7080.sh.intel.com (HELO localhost) ([10.239.160.36]) by orviesa009.jf.intel.com with ESMTP; 23 Jul 2024 07:14:25 -0700 Date: Tue, 23 Jul 2024 22:30:09 +0800 From: Zhao Liu To: Markus Armbruster Cc: qemu-devel@nongnu.org, Laurent Vivier , Philippe =?iso-8859-1?Q?Mathieu-Daud=E9?= Subject: Re: [PATCH] hw/nubus/nubus-virtio-mmio: Fix missing ERRP_GUARD() in nubus_virtio_mmio_realize() Message-ID: References: <20240715095939.72492-1-zhao1.liu@intel.com> <878qxswgrm.fsf@pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <878qxswgrm.fsf@pond.sub.org> Received-SPF: pass client-ip=192.198.163.14; envelope-from=zhao1.liu@intel.com; helo=mgamail.intel.com X-Spam_score_int: -44 X-Spam_score: -4.5 X-Spam_bar: ---- X-Spam_report: (-4.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.133, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Hi Markus, On Tue, Jul 23, 2024 at 12:21:17PM +0200, Markus Armbruster wrote: > Date: Tue, 23 Jul 2024 12:21:17 +0200 > From: Markus Armbruster > Subject: Re: [PATCH] hw/nubus/nubus-virtio-mmio: Fix missing ERRP_GUARD() > in nubus_virtio_mmio_realize() > > Zhao Liu writes: > > > As the comment in qapi/error, dereferencing @errp requires > > Suggest "According to the comment in qapi/error.h". Thanks! Good words. > > 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 nubus_virtio_mmio_realize(), @errp is dereferenced without > > ERRP_GUARD(). > > Suggest to scratch "But". No problem, will do. > > Although nubus_virtio_mmio_realize() - as a DeviceClass.realize() > > method - doesn't get the NULL @errp parameter, it hasn't triggered the > > bug that dereferencing the NULL @errp. It's still necessary to follow > > the requirement of @errp, so add missing ERRP_GUARD() in > > nubus_virtio_mmio_realize(). > > Suggest > > Although nubus_virtio_mmio_realize() - as a DeviceClass.realize() > method - is never passed a null @errp argument, it should follow the > rules on @errp usage. Add the ERRP_GUARD() there. Thanks for the text! It sounds much more authentic! > > Cc: Laurent Vivier > > Cc: Philippe Mathieu-Daudé > > Signed-off-by: Zhao Liu > > --- > > hw/nubus/nubus-virtio-mmio.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/hw/nubus/nubus-virtio-mmio.c b/hw/nubus/nubus-virtio-mmio.c > > index 58a63c84d0be..a5558d3ec28b 100644 > > --- a/hw/nubus/nubus-virtio-mmio.c > > +++ b/hw/nubus/nubus-virtio-mmio.c > > @@ -23,6 +23,7 @@ static void nubus_virtio_mmio_set_input_irq(void *opaque, int n, int level) > > > > static void nubus_virtio_mmio_realize(DeviceState *dev, Error **errp) > > { > > + ERRP_GUARD(); > > NubusVirtioMMIODeviceClass *nvmdc = NUBUS_VIRTIO_MMIO_GET_CLASS(dev); > > NubusVirtioMMIO *s = NUBUS_VIRTIO_MMIO(dev); > > NubusDevice *nd = NUBUS_DEVICE(dev); > SysBusDevice *sbd; > int i, offset; > > nvmdc->parent_realize(dev, errp); > > Here's the dereference: > > if (*errp) { > return; > } > > Reviewed-by: Markus Armbruster > Thanks! Will refresh a v2 soon. Regards, Zhao