diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c index 217ca6129fc0..a95e4ac87c71 100644 --- a/drivers/char/virtio_console.c +++ b/drivers/char/virtio_console.c @@ -2187,9 +2187,6 @@ static int virtcons_restore(struct virtio_device *vdev) virtio_device_ready(portdev->vdev); - if (use_multiport(portdev)) - fill_queue(portdev->c_ivq, &portdev->c_ivq_lock); - list_for_each_entry(port, &portdev->ports, list) { port->in_vq = portdev->in_vqs[port->id]; port->out_vq = portdev->out_vqs[port->id]; @@ -2206,6 +2203,18 @@ static int virtcons_restore(struct virtio_device *vdev) if (port->guest_connected) send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 1); } + + /* + * Populate the control receive queue only after the list iteration + * is complete. If we fill this queue before iterating, the host could + * immediately deliver a VIRTIO_CONSOLE_PORT_REMOVE message. + * This would trigger the control workqueue, which modifies the + * portdev->ports list concurrently with the unprotected loop above, + * leading to a Use-After-Free and list corruption. + */ + if (use_multiport(portdev)) + fill_queue(portdev->c_ivq, &portdev->c_ivq_lock); + return 0; } #endif