diff --git a/drivers/media/usb/em28xx/em28xx-video.c b/drivers/media/usb/em28xx/em28xx-video.c
index 6b84c3413e83..ab8ba19cad73 100644
--- a/drivers/media/usb/em28xx/em28xx-video.c
+++ b/drivers/media/usb/em28xx/em28xx-video.c
@@ -2153,13 +2153,17 @@ static int em28xx_v4l2_open(struct file *filp)
 		return -EINVAL;
 	}
 
+	if (mutex_lock_interruptible(&dev->lock))
+		return -ERESTARTSYS;
+	if (!dev->v4l2) {
+		mutex_unlock(&dev->lock);
+		return -ENOMEM;
+	}
+
 	em28xx_videodbg("open dev=%s type=%s users=%d\n",
 			video_device_node_name(vdev), v4l2_type_names[fh_type],
 			v4l2->users);
 
-	if (mutex_lock_interruptible(&dev->lock))
-		return -ERESTARTSYS;
-
 	ret = v4l2_fh_open(filp);
 	if (ret) {
 		dev_err(&dev->intf->dev,
@@ -2885,6 +2889,7 @@ static int em28xx_v4l2_init(struct em28xx *dev)
 	return 0;
 
 unregister_dev:
+	pr_info("debug: em28xx_v4l2_init() &v4l2->vdev: %px\n", &v4l2->vdev);
 	if (video_is_registered(&v4l2->radio_dev)) {
 		dev_info(&dev->intf->dev,
 			 "V4L2 device %s deregistered\n",
diff --git a/drivers/media/v4l2-core/v4l2-dev.c b/drivers/media/v4l2-core/v4l2-dev.c
index a593ea0598b5..2ad106ede7f0 100644
--- a/drivers/media/v4l2-core/v4l2-dev.c
+++ b/drivers/media/v4l2-core/v4l2-dev.c
@@ -417,6 +417,7 @@ static int v4l2_open(struct inode *inode, struct file *filp)
 	}
 	/* and increase the device refcount */
 	video_get(vdev);
+	pr_info("debug: v4l2_open() vdev: %px\n", vdev);
 	mutex_unlock(&videodev_lock);
 	if (vdev->fops->open) {
 		if (video_is_registered(vdev))
@@ -1086,6 +1087,7 @@ void video_unregister_device(struct video_device *vdev)
 	 */
 	clear_bit(V4L2_FL_REGISTERED, &vdev->flags);
 	mutex_unlock(&videodev_lock);
+	pr_info("debug: video_unregister_device() vdev: %px\n", vdev);
 	device_unregister(&vdev->dev);
 }
 EXPORT_SYMBOL(video_unregister_device);