@@ -681,12 +681,6 @@ static void virtio_vsock_remove(struct virtio_device *vdev)
rcu_assign_pointer(the_virtio_vsock, NULL);
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 */
vsock_for_each_connected_socket(virtio_vsock_reset_sock);
@@ -741,6 +735,15 @@ static void virtio_vsock_remove(struct virtio_device *vdev)
/* Delete virtqueues and flush outstanding callbacks if any */
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);
kfree(vsock);
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: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> --- net/vmw_vsock/virtio_transport.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)