Re: [PATCH 19/29] ibmvfc: implement NVMe/FC stubs for local/remote port registration

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Unconditional NULL pointer dereference in NVMe-FC local and remote port unregistration paths.
--

commit 70b1c2d3d0ca257b156db2ba118e3a6f944e519d
Author: Tyrel Datwyler <tyreld@linux.ibm.com>

ibmvfc: implement NVMe/FC stubs for local/remote port registration

Implement the initial NVMe/FC local-port and remote-port registration
functions that notify the NVMe-FC midlayr of port discovery and loss.

> diff --git a/drivers/scsi/ibmvscsi/ibmvfc-nvme.c b/drivers/scsi/ibmvscsi/ibmvfc-nvme.c
> index 4a66cde8a8d20..202e8d0b00813 100644
> --- a/drivers/scsi/ibmvscsi/ibmvfc-nvme.c
> +++ b/drivers/scsi/ibmvscsi/ibmvfc-nvme.c
> @@ -14,10 +14,18 @@
>  
>  static void ibmvfc_nvme_localport_delete(struct nvme_fc_local_port *lport)
>  {
> +	struct ibmvfc_host *vhost = lport->private;
> +
> +	vhost->nvme_local_port = NULL;
> +	complete(&vhost->nvme_delete_done);
>  }
>  
>  static void ibmvfc_nvme_remoteport_delete(struct nvme_fc_remote_port *rport)
>  {
> +	struct ibmvfc_target *tgt = rport->private;
> +
> +	tgt->nvme_remote_port = NULL;
> +	complete(&tgt->nvme_delete_done);
>  }

[ ... ]

> @@ -70,18 +78,85 @@ static struct nvme_fc_port_template ibmvfc_nvme_fc_transport = {
>  
>  int ibmvfc_nvme_register_remoteport(struct ibmvfc_target *tgt)
>  {

[ ... ]

>  void ibmvfc_nvme_unregister_remoteport(struct ibmvfc_target *tgt)
>  {
> +	struct ibmvfc_host *vhost = tgt->vhost;
> +	struct nvme_fc_remote_port *rport = tgt->nvme_remote_port;
> +	int rc;
> +
> +	if (!tgt->nvme_remote_port)
> +		return;
> +
> +	ibmvfc_log(vhost, 2, "unregister_remoteport: traddr=nn-0x%llx:pn-0x%llx PortID:%x\n",
> +		   rport->node_name, rport->port_name, rport->port_id);
> +	init_completion(&tgt->nvme_delete_done);
> +	rc = nvme_fc_unregister_remoteport(tgt->nvme_remote_port);
> +
> +	if (!rc) {
> +		wait_for_completion(&tgt->nvme_delete_done);
> +		tgt->nvme_remote_port->private = NULL;

[Severity: High]
Does this code unconditionally dereference a NULL pointer?

When nvme_fc_unregister_remoteport() finishes, the asynchronous delete
callback ibmvfc_nvme_remoteport_delete() is called. This callback executes:

    tgt->nvme_remote_port = NULL;
    complete(&tgt->nvme_delete_done);

After waking up from wait_for_completion(), tgt->nvme_remote_port will
always be NULL, meaning the access to tgt->nvme_remote_port->private will
cause a kernel panic.

> +	}
>  }

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260623013035.3436640-1-tyreld@linux.ibm.com?part=19