diff --git a/drivers/media/video/arv.c b/drivers/media/video/arv.c
index 2666d3b76630a3d7a5048f64c4eb5851249eced7..19e9929ffa0fb74adc7c2df4ebf9944b2e551632 100644
--- a/drivers/media/video/arv.c
+++ b/drivers/media/video/arv.c
@@ -441,7 +441,7 @@ static int ar_do_ioctl(struct inode *inode, struct file *file,
 	{
 		struct video_window *w = arg;
 		DEBUG(1, "VIDIOCGWIN:\n");
-		memset(w, 0, sizeof(w));
+		memset(w, 0, sizeof(*w));
 		w->width = ar->width;
 		w->height = ar->height;
 		return 0;