[PATCH AUTOSEL 5.14 60/99] scsi: qla2xxx: Fix hang during NVMe session tear down

Sasha Levin
2021-09-10T00:44:32Z

From: Arun Easi <aeasi@marvell.com>

[ Upstream commit 310e69edfbd57995868a428eeddea09a7b5d2749 ]

The following hung task call trace was seen:

[ 1230.183294] INFO: task qla2xxx_wq:523 blocked for more than 120 seconds.
[ 1230.197749] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 1230.205585] qla2xxx_wq D 0 523 2 0x80004000
[ 1230.205636] Workqueue: qla2xxx_wq qlt_free_session_done [qla2xxx]
[ 1230.205639] Call Trace:
[ 1230.208100] __schedule+0x2c4/0x700
[ 1230.211607] schedule+0x38/0xa0
[ 1230.214769] schedule_timeout+0x246/0x2f0
[ 1230.222651] wait_for_completion+0x97/0x100
[ 1230.226921] qlt_free_session_done+0x6a0/0x6f0 [qla2xxx]
[ 1230.232254] process_one_work+0x1a7/0x360

...when device side port resets were done.

Abort threads were getting out without processing due to the "deleted"
flag check. The delete thread, meanwhile, could not proceed with a
logout (that would have cleared out pending requests) as the logout IOCB
work was not progressing. It appears like the hung qlt_free_session_done()
thread is causing the ha->wq works on hold. The qlt_free_session_done()
was hung waiting for nvme_fc_unregister_remoteport() + localport_delete cb
to be complete, which would only happen when all I/Os are released.

Fix this by allowing abort to progress until device delete is completely
done. This should make the qlt_free_session_done() proceed without hang and
thus clear up the deadlock.

Link: https://lore.kernel.org/r/20210817051315.2477-5-njavali@marvell.com
Signed-off-by: Arun Easi <aeasi@marvell.com>
Signed-off-by: Nilesh Javali <njavali@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/qla2xxx/qla_nvme.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/qla2xxx/qla_nvme.c b/drivers/scsi/qla2xxx/qla_nvme.c
index 3e5c70a1d969..6e1abfc1be41 100644
--- a/drivers/scsi/qla2xxx/qla_nvme.c
+++ b/drivers/scsi/qla2xxx/qla_nvme.c
@@ -227,7 +227,7 @@ static void qla_nvme_abort_work(struct work_struct *work)
"%s called for sp=%p, hndl=%x on fcport=%p deleted=%d\n",
__func__, sp, sp->handle, fcport, fcport->deleted);

- if (!ha->flags.fw_started || fcport->deleted)
+ if (!ha->flags.fw_started || fcport->deleted == QLA_SESS_DELETED)
goto out;

if (ha->flags.host_shutting_down) {
--
2.30.2