On Mon, Jul 12, 2021 at 11:59:37PM +0200, Pavel Machek wrote:

Hi!

quoted

From: Xie Yongji <redacted>

[ Upstream commit 17f46f488a5d82c5568e6e786cd760bba1c2ee09 ]

The dev->dev_private might not be allocated if virtio_gpu_pci_quirk()
or virtio_gpu_init() failed. In this case, we should avoid the cleanup
in virtio_gpu_release().

The check is in wrong place at least in 4.4:

quoted

+++ b/drivers/gpu/drm/virtio/virtgpu_kms.c

@@ -257,6 +257,9 @@ int virtio_gpu_driver_unload(struct drm_device *dev)
 	flush_work(&vgdev->config_changed_work);
 	vgdev->vdev->config->del_vqs(vgdev->vdev);

+	if (!vgdev)
+		return;
+

Pointer is dereferenced before being tested.

Heh, yes, thanks for catching that. I'll drop it for now and rework it
next week.

-- 
Thanks,
Sasha