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 C2485C48BC3 for ; Wed, 21 Feb 2024 15:42:35 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rcoNN-0006Ih-6a; Wed, 21 Feb 2024 10:19:13 -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 1rcoJl-0000sX-AD for qemu-devel@nongnu.org; Wed, 21 Feb 2024 10:15:29 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rckol-0005U9-Lg for qemu-devel@nongnu.org; Wed, 21 Feb 2024 06:31:18 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1708515073; 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: in-reply-to:in-reply-to:references:references; bh=DFeShg4Zc8YLMA/+QI1a+xZt/Ft3UHkKRSJD6FE+aCU=; b=ECsHl5hHJV6zl2L2gpjgNDuGbKBHIclRrtmWkTiUHOEI/KBxl3vJL7IfcFTSs8J7c9BtSw guWmbxV3Pjqq8J/2a/hY/yHpH4gCkTy2PZEFSiKCuPJ7wWhdom9w55tx+duChv02S2ASGo 6SIz0erBTZfs8th0elr7Csii82mILnQ= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-354-_qHt3OD_Nk2Ww0r03SUf7Q-1; Wed, 21 Feb 2024 06:31:09 -0500 X-MC-Unique: _qHt3OD_Nk2Ww0r03SUf7Q-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 8D76F3816B4B; Wed, 21 Feb 2024 11:31:08 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.192.55]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C7F6A8CE8; Wed, 21 Feb 2024 11:31:07 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id BD43521E66D5; Wed, 21 Feb 2024 12:31:06 +0100 (CET) From: Markus Armbruster To: Zhao Liu Cc: Jonathan Cameron , Fan Ni , Laurent Vivier , Alistair Francis , "Edgar E . Iglesias" , Peter Maydell , "Michael S . Tsirkin" , Marcel Apfelbaum , Alex Williamson , =?utf-8?Q?C=C3=A9dric?= Le Goater , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , qemu-devel@nongnu.org, qemu-arm@nongnu.org, qemu-trivial@nongnu.org, Zhao Liu Subject: Re: [PATCH 1/6] hw/cxl/cxl-host: Fix missing ERRP_GUARD() in cxl_fixed_memory_window_config() In-Reply-To: <20240221094317.994454-2-zhao1.liu@linux.intel.com> (Zhao Liu's message of "Wed, 21 Feb 2024 17:43:12 +0800") References: <20240221094317.994454-1-zhao1.liu@linux.intel.com> <20240221094317.994454-2-zhao1.liu@linux.intel.com> Date: Wed, 21 Feb 2024 12:31:06 +0100 Message-ID: <878r3evyth.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.5 Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.05, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, 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=unavailable 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 Zhao Liu writes: > 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. > * - It should not be passed to error_prepend() or > * error_append_hint(), because that doesn't work with &error_fatal. > * 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. > > Currently, 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() > doesn't trigger the dereference issue. > > 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 > --- > Suggested by credit: > Markus: Referred his explanation about ERRP_GUARD(). > --- > 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; The dereferences are 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; } We check *errp, because neither function returns a suitable error code. Reviewed-by: Markus Armbruster