Re: [PATCH 02/25] qla2xxx: Remove redundant fc_host_port_name call

[Bart Van Assche <Bart.VanAssche@sandisk.com>]

On Fri, 2017-05-19 at 14:53 -0700, Himanshu Madhani wrote:
> From: Quinn Tran <quinn.tran@cavium.com>
> 
> Remove redundant fc_host_port_name calls to prevent
> early access of scsi_host->shost_data buffer. This
> prevent null pointer access.
> 
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
> Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
> ---
>  drivers/scsi/qla2xxx/qla_mbx.c | 9 ---------
>  1 file changed, 9 deletions(-)
> 
> diff --git a/drivers/scsi/qla2xxx/qla_mbx.c b/drivers/scsi/qla2xxx/qla_mbx.c
> index a113ab3592a7..12fea77e31c6 100644
> --- a/drivers/scsi/qla2xxx/qla_mbx.c
> +++ b/drivers/scsi/qla2xxx/qla_mbx.c
> @@ -3676,15 +3676,6 @@ qla24xx_report_id_acquisition(scsi_qla_host_t *vha,
>  				qlt_update_host_map(vha, id);
>  			}
>  
> -			fc_host_port_name(vha->host) =
> -			    wwn_to_u64(vha->port_name);
> -
> -			if (qla_ini_mode_enabled(vha))
> -				ql_dbg(ql_dbg_mbx, vha, 0x1018,
> -				    "FA-WWN portname %016llx (%x)\n",
> -				    fc_host_port_name(vha->host),
> -				    rptid_entry->vp_status);
> -
>  			set_bit(REGISTER_FC4_NEEDED, &vha->dpc_flags);
>  			set_bit(REGISTER_FDMI_NEEDED, &vha->dpc_flags);
>  		} else {

Hello Himanshu,

If the above host port name assignment is redundant, what is the host
port name assignment it is redundant with?

Which of the removed statements could trigger a NULL pointer access, and
from what context? Is there perhaps a call trace available of the NULL
pointer access?

Thanks,

Bart.