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iscsi-target: Fix delayed logout processing greater than SECONDS_FOR_LOGOUT_COMP

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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@sandisk.com>
Tested-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Mike Christie <mchristi@redhat.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: stable@vger.kernel.org # 3.14+
Tested-by: Gary Guo <ghg@datera.io>
Tested-by: Chu Yuan Lin <cyl@datera.io>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Nicholas Bellinger 2017-06-03 05:35:47 -07:00
parent 73d4e580cc
commit 105fa2f44e
1 changed files with 8 additions and 2 deletions
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10
drivers/target/iscsi/iscsi_target.c
View file

@ -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);