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 D90F6C001E0 for ; Wed, 26 Jul 2023 06:44:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232151AbjGZGo1 (ORCPT ); Wed, 26 Jul 2023 02:44:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58398 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232087AbjGZGoJ (ORCPT ); Wed, 26 Jul 2023 02:44:09 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4A77F1BF8; Tue, 25 Jul 2023 23:44:06 -0700 (PDT) Received: from kwepemm600005.china.huawei.com (unknown [172.30.72.57]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4R9kml400PzCrWH; Wed, 26 Jul 2023 14:40:39 +0800 (CST) Received: from [10.67.103.158] (10.67.103.158) by kwepemm600005.china.huawei.com (7.193.23.191) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.27; Wed, 26 Jul 2023 14:44:01 +0800 Subject: Re: [PATCH] USB:bugfix a controller halt error To: Greg KH CC: , References: <20230721100015.27124-1-liulongfang@huawei.com> <2023072153-module-wannabe-5637@gregkh> From: liulongfang Message-ID: Date: Wed, 26 Jul 2023 14:44:01 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <2023072153-module-wannabe-5637@gregkh> Content-Type: text/plain; charset="gbk" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.67.103.158] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To kwepemm600005.china.huawei.com (7.193.23.191) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023/7/21 19:08, Greg KH Wrote: > On Fri, Jul 21, 2023 at 06:00:15PM +0800, liulongfang wrote: >> On systems that use ECC memory. The ECC error of the memory will >> cause the USB controller to halt. It causes the usb_control_msg() >> operation to fail. > > Why does ECC memory matter here? > This is a test conducted under a special test scenario. ECC memory errors are caused by some test tools. >> At this point, the returned buffer data is an abnormal value, and >> continuing to use it will lead to incorrect results. >> >> Therefore, it is necessary to judge the return value and exit. >> >> Signed-off-by: liulongfang >> --- >> drivers/usb/core/hub.c | 10 ++++++++++ >> 1 file changed, 10 insertions(+) >> >> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c >> index a739403a9e45..6a43198be263 100644 >> --- a/drivers/usb/core/hub.c >> +++ b/drivers/usb/core/hub.c >> @@ -4891,6 +4891,16 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1, >> USB_DT_DEVICE << 8, 0, >> buf, GET_DESCRIPTOR_BUFSIZE, >> initial_descriptor_timeout); >> + /* On systems that use ECC memory, ECC errors can >> + * cause the USB controller to halt. >> + * It causes this operation to fail. At this time, >> + * the buf data is an abnormal value and needs to be exited. >> + */ >> + if (r < 0) { >> + kfree(buf); >> + goto fail; >> + } > > Are you sure this is correct? How was this tested? Seems to me that > this will still return "success" if this code path ever happens, what am You are right. I made a patch error here. The code modification should be like this: if (r < 0) { retval = r; kfree(buf); goto fail; } thanks, Longfang. > I missing? > > thanks, > > greg k-h > . >