Commit e1f33be9 authored by Greg Kurz's avatar Greg Kurz Committed by Michael S. Tsirkin
Browse files

vhost: fix error path in vhost_init_used() 



We don't want side effects. If something fails, we rollback vq->is_le to
its previous value.

Signed-off-by: default avatarGreg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 4e94ebdd

drivers/vhost/vhost.c

+11 −4
Original line number Diff line number Diff line
@@ -1156,6 +1156,8 @@ int vhost_init_used(struct vhost_virtqueue *vq) 
{

	__virtio16 last_used_idx;

	int r;

	bool is_le = vq->is_le;



	if (!vq->private_data) {

		vq->is_le = virtio_legacy_is_little_endian();

		return 0;
@@ -1165,15 +1167,20 @@ int vhost_init_used(struct vhost_virtqueue *vq) 


	r = vhost_update_used_flags(vq);

	if (r)

		return r;

		goto err;

	vq->signalled_used_valid = false;

	if (!access_ok(VERIFY_READ, &vq->used->idx, sizeof vq->used->idx))

		return -EFAULT;

	if (!access_ok(VERIFY_READ, &vq->used->idx, sizeof vq->used->idx)) {

		r = -EFAULT;

		goto err;

	}

	r = __get_user(last_used_idx, &vq->used->idx);

	if (r)

		return r;

		goto err;

	vq->last_used_idx = vhost16_to_cpu(vq, last_used_idx);

	return 0;

err:

	vq->is_le = is_le;

	return r;

}

EXPORT_SYMBOL_GPL(vhost_init_used);