s->r.height *= factor;
                if (dev->bitmap_out && (compose->width != s->r.width ||
                                        compose->height != s->r.height)) {
-                       kfree(dev->bitmap_out);
+                       vfree(dev->bitmap_out);
                        dev->bitmap_out = NULL;
                }
                *compose = s->r;
                return ret;
 
        if (win->bitmap) {
-               new_bitmap = memdup_user(win->bitmap, bitmap_size);
+               new_bitmap = vzalloc(bitmap_size);
 
-               if (IS_ERR(new_bitmap))
-                       return PTR_ERR(new_bitmap);
+               if (!new_bitmap)
+                       return -ENOMEM;
+               if (copy_from_user(new_bitmap, win->bitmap, bitmap_size)) {
+                       vfree(new_bitmap);
+                       return -EFAULT;
+               }
        }
 
        dev->overlay_out_top = win->w.top;
        dev->overlay_out_left = win->w.left;
-       kfree(dev->bitmap_out);
+       vfree(dev->bitmap_out);
        dev->bitmap_out = new_bitmap;
        dev->clipcount_out = win->clipcount;
        if (dev->clipcount_out)