On Thu, Aug 11, 2022 at 12:40:09PM +0000, Eli Cohen wrote:
> > From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> > Sent: Thursday, August 11, 2022 1:40 PM
> > To: Eli Cohen <elic@xxxxxxxxxx>
> > Cc: virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
> > Subject: [bug report] vdpa/mlx5: Support different address spaces for control and data
> >
> > Hello Eli Cohen,
> >
> > The patch d5358cd0e369: "vdpa/mlx5: Support different address spaces
> > for control and data" from Jul 14, 2022, leads to the following
> > Smatch static checker warning:
> >
> > drivers/vdpa/mlx5/net/mlx5_vnet.c:2676 mlx5_vdpa_set_map()
> > error: uninitialized symbol 'err'.
> >
> > drivers/vdpa/mlx5/net/mlx5_vnet.c
> > 2657 static int mlx5_vdpa_set_map(struct vdpa_device *vdev, unsigned int asid,
> > 2658 struct vhost_iotlb *iotlb)
> > 2659 {
> > 2660 struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
> > 2661 struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
> > 2662 int err;
> > 2663
> > 2664 down_write(&ndev->reslock);
> > 2665 if (mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] == asid) {
> > 2666 err = set_map_data(mvdev, iotlb);
> > 2667 if (err)
> > 2668 goto out;
> > 2669 }
> > 2670
> > 2671 if (mvdev->group2asid[MLX5_VDPA_CVQ_GROUP] == asid)
> > 2672 err = set_map_control(mvdev, iotlb);
> >
> > err not initialized on else path. My guess is that one or both of these
> > conditions has to be true and this is a false positive but I don't know
> > the code well enough to be sure.
>
> Thanks for reporting this.
> I think it would be better to return an error if the provided asid is not recognized.
>
> Therefore I am thinking about adding something like this:
>
> if (asid != mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] &&
> asid != mvdev->group2asid[MLX5_VDPA_CVQ_GROUP]) {
> err = -EINVAL;
> goto out;
> }
I would probably chain the conditions:
if (mvdev->group2asid[MLX5_VDPA_DATAVQ_GROUP] == asid) {
} else if (mvdev->group2asid[MLX5_VDPA_CVQ_GROUP] == asid) {
} else {
err = -EINVAL;
goto out;
}
or alternatively initialize err with -EINVAL and be done with it.
> >
> > 2673
> > 2674 out:
> > 2675 up_write(&ndev->reslock);
> > --> 2676 return err;
> > 2677 }
> >
> > regards,
> > dan carpenter
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