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 98930C6FD1D for ; Thu, 23 Mar 2023 12:50:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231932AbjCWMub (ORCPT ); Thu, 23 Mar 2023 08:50:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36420 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231295AbjCWMu3 (ORCPT ); Thu, 23 Mar 2023 08:50:29 -0400 Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0183326C32; Thu, 23 Mar 2023 05:50:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1679575828; x=1711111828; h=message-id:date:mime-version:to:cc:references:from: subject:in-reply-to:content-transfer-encoding; bh=fDt3zvniKGii4PtPU48PaQrpCagZeMYbyS0cNnHtbTI=; b=Ud0iNK5aZ3eiGWaz9t/JiYK9w3nebzJSwVQrs/XZUtM60TPfrJ4nntnL oJdzgE5FyFboB2q+EIGOwl6OnWSGU134O5A+vttRa2KNnuRJm58hPVx4f mQeJF/BpkbJNOYADd7UxbdJPnz5s9lOsARKdRHdPZPbQueqHWZZ1OEzEA ere1Bfd+Wbcv3GBlfQ9Dvs7k1NjL6+aUkKbhBVnOch/3P1gwQt619Ls7P 4LzpQD5XJThaJAa9kHboxYiuAwaMh9vBPyPgal5ni5utHNSMPk+H9qPLI TAjvvbVqvWh3npwC45Fo3TeESApmjrJ+651P55TRwmDKKHjmcEfLwRunw g==; X-IronPort-AV: E=McAfee;i="6600,9927,10657"; a="319864716" X-IronPort-AV: E=Sophos;i="5.98,283,1673942400"; d="scan'208";a="319864716" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Mar 2023 05:50:20 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10657"; a="856470942" X-IronPort-AV: E=Sophos;i="5.98,283,1673942400"; d="scan'208";a="856470942" Received: from mattu-haswell.fi.intel.com (HELO [10.237.72.199]) ([10.237.72.199]) by orsmga005.jf.intel.com with ESMTP; 23 Mar 2023 05:50:18 -0700 Message-ID: <80f92044-6f3d-cdd8-a7d4-8793927a648b@linux.intel.com> Date: Thu, 23 Mar 2023 14:51:38 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0 Thunderbird/102.7.1 Content-Language: en-US To: Jia-Ju Bai , mathias.nyman@intel.com, gregkh@linuxfoundation.org, p.zabel@pengutronix.de Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org References: <20230323081329.366459-1-baijiaju@buaa.edu.cn> From: Mathias Nyman Subject: Re: [PATCH] usb: host: xhci: Add a NULL check of hcd in xhci_plat_remove() In-Reply-To: <20230323081329.366459-1-baijiaju@buaa.edu.cn> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 23.3.2023 10.13, Jia-Ju Bai wrote: > In a previous commit d7de14d74d65 ("usb: xhci_plat_remove: avoid NULL > dereference"), hcd can be NULL in usb_remove_hcd(), and thus it should > be checked before being used. hcd shouldn't be null in usb_remove_hcd() That was a bug which was properly fixed shortly after in: 4a593a62a9e3 xhci: Fix null pointer dereference in remove if xHC has only one roothub I guess commit d7de14d74d65 ("usb: xhci_plat_remove: avoid NULL dereference") Isn't really needed either anymore, but no harm in keeping it. > > However, in the call stack of this commit, hci is also used to get xhci: > > xhci_plat_remove() > xhci = hcd_to_xhci(hcd) > usb_hcd_is_primary_hcd(hcd) > if (!hcd->primary_hcd) -> No check for hcd > primary_hcd = hcd->primary_hcd; -> No check for hcd > usb_remove_hcd(hcd) > if (!hcd) -> Add a check by the previous commit These hcd checks shouldn't be needed. Thanks Mathias