[PATCH] virtio-gpu: fix shift wrapping bug in virtio_gpu_fence_event_create()

[Chia-I Wu]

On Thu, Sep 15, 2022 at 4:14 AM Dan Carpenter <dan.carpenter at oracle.com> wrote:
>
> The ->ring_idx_mask variable is a u64 so static checkers, Smatch in
> this case, complain if the BIT() is not also a u64.
>
> drivers/gpu/drm/virtio/virtgpu_ioctl.c:50 virtio_gpu_fence_event_create()
> warn: should '(1 << ring_idx)' be a 64 bit type?
>
> Fixes: cd7f5ca33585 ("drm/virtio: implement context init: add virtio_gpu_fence_event")
> Signed-off-by: Dan Carpenter <dan.carpenter at oracle.com>
> ---
>  drivers/gpu/drm/virtio/virtgpu_ioctl.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> index 3b1701607aae..14eedb75f8a8 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
> @@ -47,7 +47,7 @@ static int virtio_gpu_fence_event_create(struct drm_device *dev,
>         struct virtio_gpu_fence_event *e = NULL;
>         int ret;
>
> -       if (!(vfpriv->ring_idx_mask & (1 << ring_idx)))
> +       if (!(vfpriv->ring_idx_mask & (1ULL << ring_idx)))
BIT_ULL(ring_indx)?

>                 return 0;
>
>         e = kzalloc(sizeof(*e), GFP_KERNEL);
> --
> 2.35.1
>