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

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

[ Upstream commit c5749639f2d0a1f6cbe187d05f70c2e7c544d748 ]

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: 4b1068f5d74b ("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>