On Wed, Sep 04, 2019 at 04:10:30PM -0700, Chia-I Wu wrote:
> On Wed, Sep 4, 2019 at 12:48 AM Gerd Hoffmann <kraxel@xxxxxxxxxx> wrote:
> >
> > Only call virtio_gpu_array_add_fence if we actually have a fence.
> >
> > Fixes: da758d51968a ("drm/virtio: rework virtio_gpu_execbuffer_ioctl fencing")
> > Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
> > ---
> > drivers/gpu/drm/virtio/virtgpu_vq.c | 9 +++++----
> > 1 file changed, 5 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
> > index 595fa6ec2d58..7fd2851f7b97 100644
> > --- a/drivers/gpu/drm/virtio/virtgpu_vq.c
> > +++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
> > @@ -339,11 +339,12 @@ static void virtio_gpu_queue_fenced_ctrl_buffer(struct virtio_gpu_device *vgdev,
> > goto again;
> > }
> >
> > - if (fence)
> > + if (fence) {
> > virtio_gpu_fence_emit(vgdev, hdr, fence);
> > - if (vbuf->objs) {
> > - virtio_gpu_array_add_fence(vbuf->objs, &fence->f);
> > - virtio_gpu_array_unlock_resv(vbuf->objs);
> > + if (vbuf->objs) {
> > + virtio_gpu_array_add_fence(vbuf->objs, &fence->f);
> > + virtio_gpu_array_unlock_resv(vbuf->objs);
> > + }
> This leaks when fence == NULL and vbuf->objs != NULL (which can really
> happen IIRC... not at my desk to check).
Yes, it can happen, for example when flushing dumb buffers.
But I don't think we leak in this case. The code paths which don't need
a fence also do not call virtio_gpu_array_lock_resv(), so things are
balanced. The actual release of the objs happens in
virtio_gpu_dequeue_ctrl_func() via virtio_gpu_array_put_free_delayed().
cheers,
Gerd
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