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 81A36C48BC3 for ; Wed, 21 Feb 2024 15:54:06 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rcoTt-0007WL-1J; Wed, 21 Feb 2024 10:25:57 -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 1rcoMj-0004vg-Q8; Wed, 21 Feb 2024 10:18:38 -0500 Received: from mgamail.intel.com ([192.198.163.13]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rcnyC-0006w4-Bw; Wed, 21 Feb 2024 09:53:13 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1708527192; x=1740063192; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=UGj5JoIo7Cr9pGUnX7V/P0tJcuLD76ovvoOQLggI0D8=; b=it9xlkMuuFBVDvlQyist1CgBj7T6GYrUbkdDil2rbFT/GVkHhGygTnwK y6qumUGgvOWZSshevTsrdhEVqT6sHjR4/7GBxZdzU2WQqr8emiY5GYdNk TUNaQDgXfzTdwzG809Ql+WEbdZNzXjkBaRgzqtgPr2KtFMB30W3FW15hh kGstlUvQ3+83zYR/8Hj1G7u6xHs75wdmc3ilJmUoTkYWR5ZoseLcRoxuC gDHXQ0ODM6MaTAaJNHrvlvl605AIXha6hoHGtYzMl5wJgyEMAJzjOXNF7 KdNtgrscw9SYKfWfUaOv28Kjb//tSsT3t8XQMNdmsB81KrpLBBX5YSDjq w==; X-IronPort-AV: E=McAfee;i="6600,9927,10990"; a="5643881" X-IronPort-AV: E=Sophos;i="6.06,175,1705392000"; d="scan'208";a="5643881" Received: from fmviesa002.fm.intel.com ([10.60.135.142]) by fmvoesa107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Feb 2024 06:53:09 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.06,175,1705392000"; d="scan'208";a="28302334" Received: from liuzhao-optiplex-7080.sh.intel.com (HELO localhost) ([10.239.160.36]) by fmviesa002.fm.intel.com with ESMTP; 21 Feb 2024 06:53:04 -0800 Date: Wed, 21 Feb 2024 23:06:44 +0800 From: Zhao Liu To: Markus Armbruster Cc: Jonathan Cameron , 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?= , qemu-devel@nongnu.org, qemu-arm@nongnu.org, qemu-trivial@nongnu.org, Zhao Liu Subject: Re: [PATCH 4/6] hw/misc/xlnx-versal-trng: Fix missing ERRP_GUARD() in trng_prop_fault_event_set() Message-ID: References: <20240221094317.994454-1-zhao1.liu@linux.intel.com> <20240221094317.994454-5-zhao1.liu@linux.intel.com> <87ttm2ujhm.fsf@pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87ttm2ujhm.fsf@pond.sub.org> Received-SPF: none client-ip=192.198.163.13; envelope-from=zhao1.liu@linux.intel.com; helo=mgamail.intel.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.05, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_NONE=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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Wed, Feb 21, 2024 at 12:47:33PM +0100, Markus Armbruster wrote: > Date: Wed, 21 Feb 2024 12:47:33 +0100 > From: Markus Armbruster > Subject: Re: [PATCH 4/6] hw/misc/xlnx-versal-trng: Fix missing ERRP_GUARD() > in trng_prop_fault_event_set() > > 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 trng_prop_fault_event_set() doesn't get the NULL errp > > parameter as a "set" method of object property, it doesn't trigger the > > dereference issue. > > > > To follow the requirement of errp, add missing ERRP_GUARD() in > > trng_prop_fault_event_set(). > > > > Suggested-by: Markus Armbruster > > Signed-off-by: Zhao Liu > > --- > > Suggested by credit: > > Markus: Referred his explanation about ERRP_GUARD(). > > --- > > hw/misc/xlnx-versal-trng.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/hw/misc/xlnx-versal-trng.c b/hw/misc/xlnx-versal-trng.c > > index b8111b8b6626..3579348a9d17 100644 > > --- a/hw/misc/xlnx-versal-trng.c > > +++ b/hw/misc/xlnx-versal-trng.c > > @@ -33,6 +33,7 @@ > > #include "qemu/error-report.h" > > #include "qemu/guest-random.h" > > #include "qemu/timer.h" > > +#include "qapi/error.h" > > #include "qapi/visitor.h" > > #include "migration/vmstate.h" > > #include "hw/qdev-properties.h" > > @@ -641,6 +642,7 @@ static void trng_prop_fault_event_set(Object *obj, Visitor *v, > > const char *name, void *opaque, > > Error **errp) > > { > > + ERRP_GUARD(); > > Property *prop = opaque; > > uint32_t *events = object_field_prop_ptr(obj, prop); > > visit_type_uint32(v, name, events, errp); > if (*errp) { > return; > } > > Please do this instead: > > diff --git a/hw/misc/xlnx-versal-trng.c b/hw/misc/xlnx-versal-trng.c > index b8111b8b66..6495188dc7 100644 > --- a/hw/misc/xlnx-versal-trng.c > +++ b/hw/misc/xlnx-versal-trng.c > @@ -644,8 +644,7 @@ static void trng_prop_fault_event_set(Object *obj, Visitor *v, > Property *prop = opaque; > uint32_t *events = object_field_prop_ptr(obj, prop); > > - visit_type_uint32(v, name, events, errp); > - if (*errp) { > + if (!visit_type_uint32(v, name, events, errp)) { > return; > } > Thanks! I didn't think of that. Will do this. Regards, Zhao