Re: [PATCH] vhost: fix null pointer dereference in vhost_del_umem_range

[David Miller <davem@xxxxxxxxxxxxx>]

From: Denis Kirjanov <kda@xxxxxxxxxxxxxxxxx>
Date: Tue,  9 Jul 2019 13:42:51 +0200

> @@ -962,7 +962,8 @@ static void vhost_del_umem_range(struct vhost_umem *umem,
>  
>  	while ((node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
>  							   start, end)))
> -		vhost_umem_free(umem, node);
> +		if (node)
> +			vhost_umem_free(umem, node);

If 'node' is NULL we will not be in the body of the loop as per
the while() condition.

How did you test this?