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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,UNPARSEABLE_RELAY 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 86E78C43441 for ; Thu, 29 Nov 2018 02:35:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 40E49206B6 for ; Thu, 29 Nov 2018 02:35:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="Xd3cu6ev" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 40E49206B6 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.com 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 S1727754AbeK2NjQ (ORCPT ); Thu, 29 Nov 2018 08:39:16 -0500 Received: from aserp2120.oracle.com ([141.146.126.78]:58982 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727022AbeK2NjP (ORCPT ); Thu, 29 Nov 2018 08:39:15 -0500 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.22/8.16.0.22) with SMTP id wAT2Y66Z084550; Thu, 29 Nov 2018 02:34:15 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=to : cc : subject : from : references : date : in-reply-to : message-id : mime-version : content-type; s=corp-2018-07-02; bh=RRYOjySoQRUJYlwueEMVI3P/yQguc9IzJUD2fgOuECs=; b=Xd3cu6evgM+mS6VcjJPxkeljOO5WnOXPsXj6BvP7y1ddWnqTpkyHL7NbPZ3xtXyNb9wZ A26L60QrnrXpHK+JPFQKf6ck6hrYi/osz48L8KgCGK9GEn9zMCoNanUrtplfv+Fk8gt7 jVtloo7kHmhdeEjV0jnyfgZWOBTeVlsXvWtIENGUWAYncaHmNzpPoj1MB26++1JCR104 PV5W25FaJ72f5Ude7XbkViZPYPYA5t9b4D+tRdh+S0FNbyPe+eaLDW6NCbgqZ7FzdgMP QTkgSav5yrieWrd7T/5xGmWSrPH+moDicaByI3u/ILcFjCQ0ue3jmgE1rDRUTB01hP53 aw== Received: from userv0022.oracle.com (userv0022.oracle.com [156.151.31.74]) by aserp2120.oracle.com with ESMTP id 2nxxkqnn88-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 29 Nov 2018 02:34:15 +0000 Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userv0022.oracle.com (8.14.4/8.14.4) with ESMTP id wAT2YEZp027037 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 29 Nov 2018 02:34:14 GMT Received: from abhmp0017.oracle.com (abhmp0017.oracle.com [141.146.116.23]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id wAT2YCMk016493; Thu, 29 Nov 2018 02:34:12 GMT Received: from ca-mkp.ca.oracle.com (/10.159.214.123) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 28 Nov 2018 18:34:11 -0800 To: kys@linuxonhyperv.com Cc: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, devel@linuxdriverproject.org, ohering@suse.com, James.Bottomley@HansenPartnership.com, hch@infradead.org, linux-scsi@vger.kernel.org, apw@canonical.com, vkuznets@redhat.com, jasowang@redhat.com, martin.petersen@oracle.com, hare@suse.de, kys@microsoft.com, Dexuan Cui , stable@vger.kernel.org, Long Li , Stephen Hemminger , Haiyang Zhang Subject: Re: [PATCH] scsi: storvsc: Fix a race in sub-channel creation that can cause panic From: "Martin K. Petersen" Organization: Oracle Corporation References: <20181126002617.7398-1-kys@linuxonhyperv.com> Date: Wed, 28 Nov 2018 21:34:03 -0500 In-Reply-To: <20181126002617.7398-1-kys@linuxonhyperv.com> (kys@linuxonhyperv.com's message of "Mon, 26 Nov 2018 00:26:17 +0000") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9091 signatures=668686 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=1 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=797 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1811290018 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org KY, > From: Dexuan Cui > > We can concurrently try to open the same sub-channel from 2 paths: > > path #1: vmbus_onoffer() -> vmbus_process_offer() -> handle_sc_creation(). > path #2: storvsc_probe() -> storvsc_connect_to_vsp() -> > -> storvsc_channel_init() -> handle_multichannel_storage() -> > -> vmbus_are_subchannels_present() -> handle_sc_creation(). > > They conflict with each other, but it was not an issue before the recent > commit ae6935ed7d42 ("vmbus: split ring buffer allocation from open"), > because at the beginning of vmbus_open() we checked newchannel->state so > only one path could succeed, and the other would return with -EINVAL. Applied to 4.20/scsi-fixes. Thank you! -- Martin K. Petersen Oracle Linux Engineering