On 1/27/22 22:12, John Garry wrote:
> Currently a use-after-free may occur if a sas_task is aborted by the upper
> layer before we handle the IO completion in mpi_ssp_completion() or
> mpi_sata_completion().
>
> In this case, the following are the two steps in handling those IO
> completions:
> - call complete() to inform the upper layer handler of completion of
> the IO
> - release driver resources associated with the sas_task in
> pm8001_ccb_task_free() call
>
> When complete() is called, the upper layer may free the sas_task. As such,
> we should not touch the associated sas_task afterwards, but we do so in
> the pm8001_ccb_task_free() call.
>
> Fix by swapping the complete() and pm8001_ccb_task_free() calls ordering.
>
> Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
> ---
> drivers/scsi/pm8001/pm80xx_hwi.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/scsi/pm8001/pm80xx_hwi.c b/drivers/scsi/pm8001/pm80xx_hwi.c
> index ce38a2298e75..1134e86ac928 100644
> --- a/drivers/scsi/pm8001/pm80xx_hwi.c
> +++ b/drivers/scsi/pm8001/pm80xx_hwi.c
> @@ -2185,9 +2185,9 @@ mpi_ssp_completion(struct pm8001_hba_info *pm8001_ha, void *piomb)
> pm8001_dbg(pm8001_ha, FAIL,
> "task 0x%p done with io_status 0x%x resp 0x%x stat 0x%x but aborted by upper layer!\n",
> t, status, ts->resp, ts->stat);
> + pm8001_ccb_task_free(pm8001_ha, t, ccb, tag);
> if (t->slow_task)
> complete(&t->slow_task->completion);
> - pm8001_ccb_task_free(pm8001_ha, t, ccb, tag);
> } else {
> spin_unlock_irqrestore(&t->task_state_lock, flags);
> pm8001_ccb_task_free(pm8001_ha, t, ccb, tag);
> @@ -2794,9 +2794,9 @@ mpi_sata_completion(struct pm8001_hba_info *pm8001_ha,
> pm8001_dbg(pm8001_ha, FAIL,
> "task 0x%p done with io_status 0x%x resp 0x%x stat 0x%x but aborted by upper layer!\n",
> t, status, ts->resp, ts->stat);
> + pm8001_ccb_task_free(pm8001_ha, t, ccb, tag);
> if (t->slow_task)
> complete(&t->slow_task->completion);
> - pm8001_ccb_task_free(pm8001_ha, t, ccb, tag);
> } else {
> spin_unlock_irqrestore(&t->task_state_lock, flags);
> spin_unlock_irqrestore(&circularQ->oq_lock,
Reviewed-by: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx>
--
Damien Le Moal
Western Digital Research
