xen/gntdev: Fix partial gntdev_mmap() cleanup

When cleaning up after a partially successful gntdev_mmap(), unmap the successfully mapped grant pages otherwise Xen will kill the domain if in debug mode (Attempt to implicitly unmap a granted PTE) or Linux will kill the process and emit "BUG: Bad page map in process" if Xen is in release mode. This is only needed when use_ptemod is true because gntdev_put_map() will unmap grant pages itself when use_ptemod is false. Signed-off-by: Ross Lagerwall <[email protected]> Reviewed-by: Boris Ostrovsky <[email protected]> Signed-off-by: Boris Ostrovsky <[email protected]>
MaxKrummenacher · Jan 10, 2018 · cf2acf6 · cf2acf6
1 parent 951a010
commit cf2acf6
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
@@ -1071,8 +1071,10 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
 out_unlock_put:
 	mutex_unlock(&priv->lock);
 out_put_map:
-	if (use_ptemod)
+	if (use_ptemod) {
 		map->vma = NULL;
+		unmap_grant_pages(map, 0, map->count);
+	}
 	gntdev_put_map(priv, map);
 	return err;
 }