Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751256AbdFCV35 (ORCPT ); Sat, 3 Jun 2017 17:29:57 -0400 Received: from mail.linux-iscsi.org ([67.23.28.174]:34179 "EHLO linux-iscsi.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751211AbdFCV3z (ORCPT ); Sat, 3 Jun 2017 17:29:55 -0400 From: "Nicholas A. Bellinger" To: target-devel Cc: linux-scsi , lkml , Nicholas Bellinger , Mike Christie , Hannes Reinecke , Sagi Grimberg Subject: [PATCH] iscsi-target: Fix delayed logout processing greater than SECONDS_FOR_LOGOUT_COMP Date: Sat, 3 Jun 2017 21:32:54 +0000 Message-Id: <1496525574-26784-1-git-send-email-nab@linux-iscsi.org> X-Mailer: git-send-email 1.7.2.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2638 Lines: 67 From: Nicholas Bellinger This patch fixes a BUG() in iscsit_close_session() that could be triggered when iscsit_logout_post_handler() execution from within tx thread context was not run for more than SECONDS_FOR_LOGOUT_COMP (15 seconds), and the TCP connection didn't already close before then forcing tx thread context to automatically exit. This would manifest itself during explicit logout as: [33206.974254] 1 connection(s) still exist for iSCSI session to iqn.1993-08.org.debian:01:3f5523242179 [33206.980184] INFO: NMI handler (kgdb_nmi_handler) took too long to run: 2100.772 msecs [33209.078643] ------------[ cut here ]------------ [33209.078646] kernel BUG at drivers/target/iscsi/iscsi_target.c:4346! Normally when explicit logout attempt fails, the tx thread context exits and iscsit_close_connection() from rx thread context does the extra cleanup once it detects conn->conn_logout_remove has not been cleared by the logout type specific post handlers. To address this special case, if the logout post handler in tx thread context detects conn->tx_thread_active has already been cleared, simply return and exit in order for existing iscsit_close_connection() logic from rx thread context do failed logout cleanup. Reported-by: Bart Van Assche Cc: Mike Christie Cc: Hannes Reinecke Cc: Sagi Grimberg Cc: stable@vger.kernel.org # 3.14+ Signed-off-by: Nicholas Bellinger --- drivers/target/iscsi/iscsi_target.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c index 0d8f815..c025451 100644 --- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -4423,8 +4423,11 @@ static void iscsit_logout_post_handler_closesession( * always sleep waiting for RX/TX thread shutdown to complete * within iscsit_close_connection(). */ - if (!conn->conn_transport->rdma_shutdown) + if (!conn->conn_transport->rdma_shutdown) { sleep = cmpxchg(&conn->tx_thread_active, true, false); + if (!sleep) + return; + } atomic_set(&conn->conn_logout_remove, 0); complete(&conn->conn_logout_comp); @@ -4440,8 +4443,11 @@ static void iscsit_logout_post_handler_samecid( { int sleep = 1; - if (!conn->conn_transport->rdma_shutdown) + if (!conn->conn_transport->rdma_shutdown) { sleep = cmpxchg(&conn->tx_thread_active, true, false); + if (!sleep) + return; + } atomic_set(&conn->conn_logout_remove, 0); complete(&conn->conn_logout_comp); -- 1.9.1