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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 E9CBDC33CA2 for ; Wed, 8 Jan 2020 11:53:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C8041206ED for ; Wed, 8 Jan 2020 11:53:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727491AbgAHLxt (ORCPT ); Wed, 8 Jan 2020 06:53:49 -0500 Received: from lhrrgout.huawei.com ([185.176.76.210]:2235 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726290AbgAHLxs (ORCPT ); Wed, 8 Jan 2020 06:53:48 -0500 Received: from lhreml708-cah.china.huawei.com (unknown [172.18.7.108]) by Forcepoint Email with ESMTP id 3E7AA4C5978AABF20FD3; Wed, 8 Jan 2020 11:53:47 +0000 (GMT) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by lhreml708-cah.china.huawei.com (10.201.108.49) with Microsoft SMTP Server (TLS) id 14.3.408.0; Wed, 8 Jan 2020 11:53:46 +0000 Received: from [127.0.0.1] (10.202.226.43) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Wed, 8 Jan 2020 11:53:46 +0000 Subject: Re: [PATCH v1] driver core: Use list_del_init to replace list_del at device_links_purge() To: Luo Jiaxing , , , , , CC: , , "linux-scsi@vger.kernel.org" , "Martin K . Petersen" References: <1578483244-50723-1-git-send-email-luojiaxing@huawei.com> From: John Garry Message-ID: <875eb2dc-a0d3-72e5-a27b-48fa38687c8c@huawei.com> Date: Wed, 8 Jan 2020 11:53:45 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.1.2 MIME-Version: 1.0 In-Reply-To: <1578483244-50723-1-git-send-email-luojiaxing@huawei.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.226.43] X-ClientProxiedBy: lhreml729-chm.china.huawei.com (10.201.108.80) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/01/2020 11:34, Luo Jiaxing wrote: + linux-scsi, Martin > We found that enabling kernel compilation options CONFIG_SCSI_ENCLOSURE and > CONFIG_ENCLOSURE_SERVICES, repeated initialization and deletion of the same > SCSI device will cause system panic, as follows: > [72.425705] Unable to handle kernel paging request at virtual address > dead000000000108 > ... > [72.595093] Call trace: > [72.597532] device_del + 0x194 / 0x3a0 > [72.601012] enclosure_remove_device + 0xbc / 0xf8 > [72.605445] ses_intf_remove + 0x9c / 0xd8 > [72.609185] device_del + 0xf8 / 0x3a0 > [72.612576] device_unregister + 0x14 / 0x30 > [72.616489] __scsi_remove_device + 0xf4 / 0x140 > [72.620747] scsi_remove_device + 0x28 / 0x40 > [72.624745] scsi_remove_target + 0x1c8 / 0x220 please share the full crash stack frame and the commands used to trigger it. Some people prefer the timestamp removed also. > > After analysis, we see that in the error scenario, the ses module has the > following calling sequence: > device_register() -> device_del() -> device_add() -> device_del(). > The first call to device_del() is fine, but the second call to device_del() > will cause a system panic. > > Through disassembly, we locate that panic happen when device_links_purge() > call list_del() to remove device_links.needs_suppliers from list, and > list_del() will set this list entry's prev and next pointers to poison. > So if INIT_LIST_HEAD() is not re-executed before the next list_del(), It > will cause the system to access a memory address which is posioned. > > Therefore, replace list_del() with list_del_init() can avoid such issue. > > Fixes: e2ae9bcc4aaa ("driver core: Add support for linking devices during device addition") > Signed-off-by: Luo Jiaxing > Reviewed-by: John Garry This tag was only implicitly granted, but I thought that the fix looked ok, so: Reviewed-by: John Garry > --- > drivers/base/core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/base/core.c b/drivers/base/core.c > index 42a6724..7b9b0d6 100644 > --- a/drivers/base/core.c > +++ b/drivers/base/core.c > @@ -1103,7 +1103,7 @@ static void device_links_purge(struct device *dev) > struct device_link *link, *ln; > > mutex_lock(&wfs_lock); > - list_del(&dev->links.needs_suppliers); > + list_del_init(&dev->links.needs_suppliers); > mutex_unlock(&wfs_lock); > > /* >