From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:46074 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754089AbeDVN6G (ORCPT ); Sun, 22 Apr 2018 09:58:06 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Long Li , Steve French , Ronnie Sahlberg Subject: [PATCH 4.16 048/196] cifs: smbd: avoid reconnect lockup Date: Sun, 22 Apr 2018 15:51:08 +0200 Message-Id: <20180422135106.570822475@linuxfoundation.org> In-Reply-To: <20180422135104.278511750@linuxfoundation.org> References: <20180422135104.278511750@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Long Li commit 48f238a79f668f8ff013024d83010de551833d7f upstream. During transport reconnect, other processes may have registered memory and blocked on transport. This creates a deadlock situation because the transport resources can't be freed, and reconnect is blocked. Fix this by returning to upper layer on timeout. Before returning, transport status is set to reconnecting so other processes will release memory registration resources. Upper layer will retry the reconnect. This is not in fast I/O path so setting the timeout to 5 seconds. Signed-off-by: Long Li Signed-off-by: Steve French Reviewed-by: Ronnie Sahlberg CC: Stable Signed-off-by: Greg Kroah-Hartman --- fs/cifs/smbdirect.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) --- a/fs/cifs/smbdirect.c +++ b/fs/cifs/smbdirect.c @@ -1498,8 +1498,8 @@ int smbd_reconnect(struct TCP_Server_Inf log_rdma_event(INFO, "reconnecting rdma session\n"); if (!server->smbd_conn) { - log_rdma_event(ERR, "rdma session already destroyed\n"); - return -EINVAL; + log_rdma_event(INFO, "rdma session already destroyed\n"); + goto create_conn; } /* @@ -1512,15 +1512,19 @@ int smbd_reconnect(struct TCP_Server_Inf } /* wait until the transport is destroyed */ - wait_event(server->smbd_conn->wait_destroy, - server->smbd_conn->transport_status == SMBD_DESTROYED); + if (!wait_event_timeout(server->smbd_conn->wait_destroy, + server->smbd_conn->transport_status == SMBD_DESTROYED, 5*HZ)) + return -EAGAIN; destroy_workqueue(server->smbd_conn->workqueue); kfree(server->smbd_conn); +create_conn: log_rdma_event(INFO, "creating rdma session\n"); server->smbd_conn = smbd_get_connection( server, (struct sockaddr *) &server->dstaddr); + log_rdma_event(INFO, "created rdma session info=%p\n", + server->smbd_conn); return server->smbd_conn ? 0 : -ENOENT; }