Re: [PATCH v2] scsi: qedi: Fix use after free bug in qedi_remove due to race condition

[Zheng Hacker]

Mike Christie <michael.christie@xxxxxxxxxx> 于2023年4月20日周四 23:39写道：
>
> On 4/12/23 10:34 PM, Zheng Wang wrote:
> > In qedi_probe, it calls __qedi_probe, which bound &qedi->recovery_work
> > with qedi_recovery_handler and bound &qedi->board_disable_work
> > with qedi_board_disable_work.
> >
> > When it calls qedi_schedule_recovery_handler, it will finally
> > call schedule_delayed_work to start the work.
> >
> > When we call qedi_remove to remove the driver, there
> > may be a sequence as follows:
> >
> > Fix it 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
> >
> > Fixes: 4b1068f5d74b ("scsi: qedi: Add MFW error recovery process")
> > Signed-off-by: Zheng Wang <zyytlz.wz@xxxxxxx>
> > ---
> > v2:
> > - remove unnecessary comment suggested by Mike Christie and cancel the work
> > after qedi_ops->stop and qedi_ops->ll2->stop which ensure there is no more
> > work suggested by Manish Rangankar
>
> Look ok to me now. Thanks.
>
> Reviewed-by: Mike Christie <michael.christie@xxxxxxxxxx>

Thanks for your review.

Best regards,
Zheng