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Wed, 20 Jun 2018 05:26:20 +0000 Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userv0021.oracle.com (8.14.4/8.14.4) with ESMTP id w5K5QIca021754 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 20 Jun 2018 05:26:19 GMT Received: from abhmp0001.oracle.com (abhmp0001.oracle.com [141.146.116.7]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id w5K5QH8K005865; Wed, 20 Jun 2018 05:26:17 GMT Received: from [10.182.69.179] (/10.182.69.179) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 19 Jun 2018 22:26:17 -0700 Subject: Re: [PATCH] nvme-pci: not invoke nvme_remove_dead_ctrl when change state fails To: Keith Busch Cc: axboe@fb.com, sagi@grimberg.me, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, keith.busch@intel.com, hch@lst.de References: <1529397050-7524-1-git-send-email-jianchao.w.wang@oracle.com> <20180619163952.GE19922@localhost.localdomain> From: "jianchao.wang" Message-ID: <7d2d346b-91f0-adad-1e11-e5ff660fb984@oracle.com> Date: Wed, 20 Jun 2018 13:26:35 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20180619163952.GE19922@localhost.localdomain> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8929 signatures=668702 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1805220000 definitions=main-1806200062 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Keith On 06/20/2018 12:39 AM, Keith Busch wrote: > On Tue, Jun 19, 2018 at 04:30:50PM +0800, Jianchao Wang wrote: >> There is race between nvme_remove and nvme_reset_work that can >> lead to io hang. >> >> nvme_remove nvme_reset_work >> -> change state to DELETING >> -> fail to change state to LIVE >> -> nvme_remove_dead_ctrl >> -> nvme_dev_disable >> -> quiesce request_queue >> -> queue remove_work >> -> cancel_work_sync reset_work >> -> nvme_remove_namespaces >> -> splice ctrl->namespaces >> nvme_remove_dead_ctrl_work >> -> nvme_kill_queues >> -> nvme_ns_remove do nothing >> -> blk_cleanup_queue >> -> blk_freeze_queue >> Finally, the request_queue is quiesced state when wait freeze, >> we will get io hang here. >> >> In fact, when fails to change state in nvme_reset_work, the only >> reason is someone has changed state to DELETING. So it is not >> necessary to invoke nvme_remove_dead_ctrl in that case. >> >> Signed-off-by: Jianchao Wang > > Good catch. I think the fix should either have the nvme_dev_disable set > shutdown to true to indicate the controller isn't coming back online, or > move the nvme_kill_queues inside nvme_remove_dead_ctrl. Yes,just not invoking nvme_remove_dead_ctrl when change state fails couldn't fix the hole completely. I prefer to move nvme_kill_queues from nvme_remove_dead_ctrl_work to nvme_remove_dead_ctrl. Will post the V2 version based on this. Thanks Jianchao