This is a note to let you know that I've just added the patch titled iscsi-target: Fix delayed logout processing greater than SECONDS_FOR_LOGOUT_COMP to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: iscsi-target-fix-delayed-logout-processing-greater-than-seconds_for_logout_comp.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 105fa2f44e504c830697b0c794822112d79808dc Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> Date: Sat, 3 Jun 2017 05:35:47 -0700 Subject: iscsi-target: Fix delayed logout processing greater than SECONDS_FOR_LOGOUT_COMP From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> commit 105fa2f44e504c830697b0c794822112d79808dc upstream. 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 <bart.vanassche@xxxxxxxxxxx> Tested-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx> Cc: Mike Christie <mchristi@xxxxxxxxxx> Cc: Hannes Reinecke <hare@xxxxxxx> Cc: Sagi Grimberg <sagig@xxxxxxxxxxxx> Tested-by: Gary Guo <ghg@xxxxxxxxx> Tested-by: Chu Yuan Lin <cyl@xxxxxxxxx> Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/target/iscsi/iscsi_target.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) --- a/drivers/target/iscsi/iscsi_target.c +++ b/drivers/target/iscsi/iscsi_target.c @@ -4431,8 +4431,11 @@ static void iscsit_logout_post_handler_c * 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); @@ -4448,8 +4451,11 @@ static void iscsit_logout_post_handler_s { 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); Patches currently in stable-queue which might be from nab@xxxxxxxxxxxxxxx are queue-4.9/iscsi-target-reject-immediate-data-underflow-larger-than-scsi-transfer-length.patch queue-4.9/iscsi-target-fix-delayed-logout-processing-greater-than-seconds_for_logout_comp.patch queue-4.9/target-fix-kref-refcount-underflow-in-transport_cmd_finish_abort.patch