Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751645AbdFIF3k (ORCPT ); Fri, 9 Jun 2017 01:29:40 -0400 Received: from mail.linux-iscsi.org ([67.23.28.174]:36213 "EHLO linux-iscsi.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751623AbdFIF3h (ORCPT ); Fri, 9 Jun 2017 01:29:37 -0400 Message-ID: <1496986176.28997.19.camel@haakon3.risingtidesystems.com> Subject: Re: [PATCH] iscsi-target: Fix delayed logout processing greater than SECONDS_FOR_LOGOUT_COMP From: "Nicholas A. Bellinger" To: target-devel Cc: linux-scsi , lkml , Mike Christie , Hannes Reinecke , Sagi Grimberg Date: Thu, 08 Jun 2017 22:29:36 -0700 In-Reply-To: <1496525574-26784-1-git-send-email-nab@linux-iscsi.org> References: <1496525574-26784-1-git-send-email-nab@linux-iscsi.org> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.4.4-1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2849 Lines: 69 Reviews pretty please..? On Sat, 2017-06-03 at 21:32 +0000, Nicholas A. Bellinger wrote: > 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);