scsi: qedi: Fix use after free bug in qedi_remove()

[ Upstream commit c574963 ]

In qedi_probe() we call __qedi_probe() which initializes
&qedi->recovery_work with qedi_recovery_handler() and
&qedi->board_disable_work with qedi_board_disable_work().

When qedi_schedule_recovery_handler() is called, schedule_delayed_work()
will finally start the work.

In qedi_remove(), which is called to remove the driver, the following
sequence may be observed:

Fix this by finishing the work before cleanup in qedi_remove().

CPU0                  CPU1

                     |qedi_recovery_handler
qedi_remove          |
  __qedi_remove      |
iscsi_host_free      |
scsi_host_put        |
//free shost         |
                     |iscsi_host_for_each_session
                     |//use qedi->shost

Cancel recovery_work and board_disable_work in __qedi_remove().

Fixes: 4b1068f ("scsi: qedi: Add MFW error recovery process")
Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
Link: https://lore.kernel.org/r/20230413033422.28003-1-zyytlz.wz@163.com
Acked-by: Manish Rangankar <mrangankar@marvell.com>
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/scsi/qedi/qedi_main.c

@@ -2450,6 +2450,9 @@ static void __qedi_remove(struct pci_dev *pdev, int mode)
 		qedi_ops->ll2->stop(qedi->cdev);
 	}
 
+	cancel_delayed_work_sync(&qedi->recovery_work);
+	cancel_delayed_work_sync(&qedi->board_disable_work);
+
 	qedi_free_iscsi_pf_param(qedi);
 
 	rval = qedi_ops->common->update_drv_state(qedi->cdev, false);