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 X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A1567C43441 for ; Wed, 21 Nov 2018 10:45:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4F77F21479 for ; Wed, 21 Nov 2018 10:45:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4F77F21479 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=c-s.fr Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729631AbeKUVTV (ORCPT ); Wed, 21 Nov 2018 16:19:21 -0500 Received: from pegase1.c-s.fr ([93.17.236.30]:20916 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726729AbeKUVTU (ORCPT ); Wed, 21 Nov 2018 16:19:20 -0500 Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 430K3P5wcTz9vF7K; Wed, 21 Nov 2018 11:45:21 +0100 (CET) X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id anB1K_LhuOkF; Wed, 21 Nov 2018 11:45:21 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 430K3P5Pw8z9vF7R; Wed, 21 Nov 2018 11:45:21 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 67FAC8B808; Wed, 21 Nov 2018 11:45:26 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id lC8aQVMCjNZT; Wed, 21 Nov 2018 11:45:26 +0100 (CET) Received: from PO15451 (po15451.idsi0.si.c-s.fr [172.25.231.2]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 2F26F8B809; Wed, 21 Nov 2018 11:45:26 +0100 (CET) Subject: Re: [PATCH 2/4] soc/fsl/qe: fix potential NULL pointer dereference in ucc_of_parse_tdm To: Wen Yang , qiang.zhao@nxp.com Cc: wang.yi59@zte.com.cn, zhong.weidong@zte.com.cn, linux-kernel@vger.kernel.org, leoyang.li@nxp.com, Julia Lawall , linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org References: <1542786111-18648-1-git-send-email-wen.yang99@zte.com.cn> From: Christophe LEROY Message-ID: Date: Wed, 21 Nov 2018 11:45:26 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.3.1 MIME-Version: 1.0 In-Reply-To: <1542786111-18648-1-git-send-email-wen.yang99@zte.com.cn> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: fr Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le 21/11/2018 à 08:41, Wen Yang a écrit : > This patch fixes a possible null pointer dereference in > ucc_of_parse_tdm, detected by the semantic patch > deref_null.cocci, with the following warning: > > ./drivers/soc/fsl/qe/qe_tdm.c:177:21-24: ERROR: pdev is NULL but dereferenced. > > The following code has potential null pointer references: > pdev = of_find_device_by_node(np2); > if (!pdev) { > ret = -EINVAL; > pr_err("%pOFn: failed to lookup pdev\n", np2); > of_node_put(np2); > goto err_miss_siram_property; > } > ... > err_miss_siram_property: > devm_iounmap(&pdev->dev, utdm->si_regs); > > Signed-off-by: Wen Yang > Reviewed-by: Tan Hu > CC: Julia Lawall > --- > drivers/soc/fsl/qe/qe_tdm.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/soc/fsl/qe/qe_tdm.c b/drivers/soc/fsl/qe/qe_tdm.c > index f78c346..166378b 100644 > --- a/drivers/soc/fsl/qe/qe_tdm.c > +++ b/drivers/soc/fsl/qe/qe_tdm.c > @@ -174,7 +174,8 @@ int ucc_of_parse_tdm(struct device_node *np, struct ucc_tdm *utdm, > return ret; > > err_miss_siram_property: > - devm_iounmap(&pdev->dev, utdm->si_regs); > + if (pdev) > + devm_iounmap(&pdev->dev, utdm->si_regs); You are just hiding the issue, not fixing it. The problem is that pdev gets modified, so in any case that devm_iounmap() will fail even when the new pdev is valid, because the iomap was done with a different pdev. Christophe > return ret; > } > EXPORT_SYMBOL(ucc_of_parse_tdm); >