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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5C401C4332F for ; Thu, 13 Oct 2022 10:56:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229534AbiJMK4w (ORCPT ); Thu, 13 Oct 2022 06:56:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56056 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229516AbiJMK4u (ORCPT ); Thu, 13 Oct 2022 06:56:50 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 42642FC1FF for ; Thu, 13 Oct 2022 03:56:49 -0700 (PDT) Received: from fraeml701-chm.china.huawei.com (unknown [172.18.147.226]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Mp5wy16whz67K2K; Thu, 13 Oct 2022 18:53:54 +0800 (CST) Received: from lhrpeml500005.china.huawei.com (7.191.163.240) by fraeml701-chm.china.huawei.com (10.206.15.50) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2375.31; Thu, 13 Oct 2022 12:56:46 +0200 Received: from localhost (10.202.226.42) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Thu, 13 Oct 2022 11:56:46 +0100 Date: Thu, 13 Oct 2022 11:56:45 +0100 From: Jonathan Cameron To: Gregory Price CC: , Michael Tsirkin , Ben Widawsky , , Huai-Cheng Kuo , Chris Browy , , Subject: Re: [PATCH v7 4/5] hw/mem/cxl-type3: Add CXL CDAT Data Object Exchange Message-ID: <20221013115645.00002873@huawei.com> In-Reply-To: References: <20221007152156.24883-1-Jonathan.Cameron@huawei.com> <20221007152156.24883-5-Jonathan.Cameron@huawei.com> X-Mailer: Claws Mail 4.0.0 (GTK+ 3.24.29; i686-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.226.42] X-ClientProxiedBy: lhrpeml500005.china.huawei.com (7.191.163.240) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-cxl@vger.kernel.org On Wed, 12 Oct 2022 12:01:54 -0400 Gregory Price wrote: > This code contains heap corruption on free, and I think should be > refactored to pre-allocate all the entries we're interested in putting > into the table. This would flatten the code and simplify the error > handling steps. > > Also, should we consider making a union with all the possible entries to > make entry allocation easier? It may eat a few extra bytes of memory, > but it would simplify the allocation/cleanup code here further. > > Given that every allocation has to be checked, i'm also not convinced > the use of g_autofree is worth the potential footguns associated with > it. > > > diff --git a/hw/mem/cxl_type3.c b/hw/mem/cxl_type3.c > > index 568c9d62f5..3fa5d70662 100644 > > --- a/hw/mem/cxl_type3.c > > +++ b/hw/mem/cxl_type3.c > > @@ -12,9 +12,218 @@ > > +static int ct3_build_cdat_table(CDATSubHeader ***cdat_table, > > + void *priv) > > +{ > (snip) > > + /* For now, no memory side cache, plausiblish numbers */ > > + dslbis_nonvolatile = g_malloc(sizeof(*dslbis_nonvolatile) * dslbis_nonvolatile_num); > > + if (!dslbis_nonvolatile) > > + return -ENOMEM; > > this allocation creates a table of entries, which is later freed > incorrectly > > > + > > + *cdat_table = g_malloc0(len * sizeof(*cdat_table)); > > this allocation needs to be checked I just realized that sizeof should be sizeof(**cdat_table) I've moved to a local autofree pointer after factoring out the guts of the code so this gets simpler anyway (and was more obviously wrong!) Jonathan