Virtualization - Jul 2021 - [PATCH AUTOSEL 4.4 08/31] drm/virtio: Fixes a potential NULL pointer dereference on probe failure

From: Xie Yongji <xieyongji at bytedance.com>

[ 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().

Signed-off-by: Xie Yongji <xieyongji at bytedance.com>
Link:
http://patchwork.freedesktop.org/patch/msgid/20210517084913.403-1-xieyongji at
bytedance.com
Signed-off-by: Gerd Hoffmann <kraxel at redhat.com>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 drivers/gpu/drm/virtio/virtgpu_kms.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/virtio/virtgpu_kms.c
b/drivers/gpu/drm/virtio/virtgpu_kms.c
index 476b9993b068..88ed5e235e55 100644
--- a/drivers/gpu/drm/virtio/virtgpu_kms.c
+++ 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;
+
 	virtio_gpu_modeset_fini(vgdev);
 	virtio_gpu_ttm_fini(vgdev);
 	virtio_gpu_free_vbufs(vgdev);
-- 
2.30.2