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Commit 0d20e56e authored by Stefano Garzarella's avatar Stefano Garzarella Committed by David S. Miller
Browse files

vsock/virtio: fix flush of works during the .remove() 



This patch moves the flush of works after vdev->config->del_vqs(vdev),
because we need to be sure that no workers run before to free the
'vsock' object.

Since we stopped the workers using the [tx|rx|event]_run flags,
we are sure no one is accessing the device while we are calling
vdev->config->reset(vdev), so we can safely move the workers' flush.

Before the vdev->config->del_vqs(vdev), workers can be scheduled
by VQ callbacks, so we must flush them after del_vqs(), to avoid
use-after-free of 'vsock' object.

Suggested-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarStefano Garzarella <sgarzare@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 17dd1367

net/vmw_vsock/virtio_transport.c

+9 −6
Original line number Original line Diff line number Diff line
@@ -680,12 +680,6 @@ static void virtio_vsock_remove(struct virtio_device *vdev) 
	rcu_assign_pointer(the_virtio_vsock, NULL);

	rcu_assign_pointer(the_virtio_vsock, NULL);

	synchronize_rcu();

	synchronize_rcu();





	flush_work(&vsock->loopback_work);

	flush_work(&vsock->rx_work);

	flush_work(&vsock->tx_work);

	flush_work(&vsock->event_work);

	flush_work(&vsock->send_pkt_work);



	/* Reset all connected sockets when the device disappear */

	/* Reset all connected sockets when the device disappear */

	vsock_for_each_connected_socket(virtio_vsock_reset_sock);

	vsock_for_each_connected_socket(virtio_vsock_reset_sock);
@@ -740,6 +734,15 @@ static void virtio_vsock_remove(struct virtio_device *vdev) 
	/* Delete virtqueues and flush outstanding callbacks if any */

	/* Delete virtqueues and flush outstanding callbacks if any */

	vdev->config->del_vqs(vdev);

	vdev->config->del_vqs(vdev);





	/* Other works can be queued before 'config->del_vqs()', so we flush

	 * all works before to free the vsock object to avoid use after free.

	 */

	flush_work(&vsock->loopback_work);

	flush_work(&vsock->rx_work);

	flush_work(&vsock->tx_work);

	flush_work(&vsock->event_work);

	flush_work(&vsock->send_pkt_work);



	mutex_unlock(&the_virtio_vsock_mutex);

	mutex_unlock(&the_virtio_vsock_mutex);





	kfree(vsock);

	kfree(vsock);