> On May 12, 2021, at 2:25 AM, Javed Hasan <jhasan@xxxxxxxxxxx> wrote:
>
> Issue :- BUG: unable to handle kernel NULL pointer dereference at 000000000000003c
> On installation of RHEL-8.3.0-20200820.n.0 distro below stack
> was generating on error.
>
> [ 14.042059] Call Trace:
> [ 14.042061] <IRQ>
> [ 14.042068] qedf_link_update+0x144/0x1f0 [qedf]
> [ 14.042117] qed_link_update+0x5c/0x80 [qed]
> [ 14.042135] qed_mcp_handle_link_change+0x2d2/0x410 [qed]
> [ 14.042155] ? qed_set_ptt+0x70/0x80 [qed]
> [ 14.042170] ? qed_set_ptt+0x70/0x80 [qed]
> [ 14.042186] ? qed_rd+0x13/0x40 [qed]
> [ 14.042205] qed_mcp_handle_events+0x437/0x690 [qed]
> [ 14.042221] ? qed_set_ptt+0x70/0x80 [qed]
> [ 14.042239] qed_int_sp_dpc+0x3a6/0x3e0 [qed]
> [ 14.042245] tasklet_action_common.isra.14+0x5a/0x100
> [ 14.042250] __do_softirq+0xe4/0x2f8
> [ 14.042253] irq_exit+0xf7/0x100
> [ 14.042255] do_IRQ+0x7f/0xd0
> [ 14.042257] common_interrupt+0xf/0xf
> [ 14.042259] </IRQ>
>
> Root cause :- API qedf_link_update() is getting called from QED.
> but by that time shost_data is not initialised. That is leading NULL pointer dereference
> when we try to derefference shost_data while updating supported_speeds.
>
> fc_host_supported_speeds(lport->host) = lport->link_supported_speeds;
>
> Expansion of fc_host_supported_speeds.
> #define fc_host_supported_speeds(x) \
> (((struct fc_host_attrs *)(x)->shost_data)->supported_speeds)
>
> Fix :- Added NULL pointer check for shost_data.
>
> Signed-off-by: Javed Hasan <jhasan@xxxxxxxxxxx>
>
> diff --git a/drivers/scsi/qedf/qedf_main.c b/drivers/scsi/qedf/qedf_main.c
> index 69f7784233f9..756231151882 100644
> --- a/drivers/scsi/qedf/qedf_main.c
> +++ b/drivers/scsi/qedf/qedf_main.c
> @@ -536,7 +536,9 @@ static void qedf_update_link_speed(struct qedf_ctx *qedf,
> if (linkmode_intersects(link->supported_caps, sup_caps))
> lport->link_supported_speeds |= FC_PORTSPEED_20GBIT;
>
> - fc_host_supported_speeds(lport->host) = lport->link_supported_speeds;
> + if (lport->host && lport->host->shost_data)
> + fc_host_supported_speeds(lport->host) =
> + lport->link_supported_speeds;
> }
>
> static void qedf_bw_update(void *dev)
> --
> 2.18.2
>
This should be sent to stable with
Fixes: 61d8658b4a435 ("scsi: qedf: Add QLogic FastLinQ offload FCoE driver framework.”)
Cc: <stable@xxxxxxxxxxxxxxx>
With above added, Looks Good.
Reviewed-by: Himanshu Madhani <himanshu.madhani@xxxxxxxxxx>
--
Himanshu Madhani Oracle Linux Engineering
