From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751349AbeA2DIL (ORCPT ); Sun, 28 Jan 2018 22:08:11 -0500 Received: from aserp2120.oracle.com ([141.146.126.78]:38360 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751249AbeA2DIK (ORCPT ); Sun, 28 Jan 2018 22:08:10 -0500 From: Jianchao Wang To: keith.busch@intel.com, axboe@fb.com, hch@lst.de, sagi@grimberg.me Cc: linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH] nvme-pci: use NOWAIT flag for nvme_set_host_mem Date: Mon, 29 Jan 2018 11:07:35 +0800 Message-Id: <1517195255-21832-1-git-send-email-jianchao.w.wang@oracle.com> X-Mailer: git-send-email 2.7.4 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8788 signatures=668655 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=2 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1711220000 definitions=main-1801290041 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org nvme_set_host_mem will invoke nvme_alloc_request without NOWAIT flag, it is unsafe for nvme_dev_disable. The adminq driver tags may have been used up when the previous outstanding adminq requests cannot be completed due to some hardware error. We have to depend on the timeout path to complete the previous outstanding adminq requests and free the tags. However, nvme_timeout will invoke nvme_dev_disable and try to get the shutdown_lock which is held by another context who is sleeping to wait for the tags to be freed by timeout path. A deadlock comes up. To fix it, let nvme_set_host_mem use NOWAIT flag. Signed-off-by: Jianchao Wang --- drivers/nvme/host/pci.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index 6fe7af0..9532529 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -1736,7 +1736,8 @@ static int nvme_set_host_mem(struct nvme_dev *dev, u32 bits) c.features.dword14 = cpu_to_le32(upper_32_bits(dma_addr)); c.features.dword15 = cpu_to_le32(dev->nr_host_mem_descs); - ret = nvme_submit_sync_cmd(dev->ctrl.admin_q, &c, NULL, 0); + ret = __nvme_submit_sync_cmd(dev->ctrl.admin_q, &c, NULL, NULL, 0, 0, + NVME_QID_ANY, 0, BLK_MQ_REQ_NOWAIT); if (ret) { dev_warn(dev->ctrl.device, "failed to set host mem (err %d, flags %#x).\n", -- 2.7.4