On Tue, Mar 22, 2022 at 10:09:06AM -0400, Michael S. Tsirkin wrote:
On Tue, Mar 22, 2022 at 03:05:00PM +0100, Stefano Garzarella wrote:On Tue, Mar 22, 2022 at 09:36:14AM -0400, Michael S. Tsirkin wrote: > On Tue, Mar 22, 2022 at 11:38:23AM +0100, Stefano Garzarella wrote: > > virtio spec requires drivers to set DRIVER_OK before using VQs. > > This is set automatically after probe returns, but virtio-vsock > > driver uses VQs in the probe function to fill rx and event VQs > > with new buffers. > > > So this is a spec violation. absolutely. > > > Let's fix this, calling virtio_device_ready() before using VQs > > in the probe function. > > > > Fixes: 0ea9e1d3a9e3 ("VSOCK: Introduce virtio_transport.ko") > > Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx> > > --- > > net/vmw_vsock/virtio_transport.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c > > index 5afc194a58bb..b1962f8cd502 100644 > > --- a/net/vmw_vsock/virtio_transport.c > > +++ b/net/vmw_vsock/virtio_transport.c > > @@ -622,6 +622,8 @@ static int virtio_vsock_probe(struct virtio_device *vdev) > > INIT_WORK(&vsock->event_work, virtio_transport_event_work); > > INIT_WORK(&vsock->send_pkt_work, virtio_transport_send_pkt_work); > > > > + virtio_device_ready(vdev); > > + > > mutex_lock(&vsock->tx_lock); > > vsock->tx_run = true; > > mutex_unlock(&vsock->tx_lock); > > Here's the whole code snippet: > > > mutex_lock(&vsock->tx_lock); > vsock->tx_run = true; > mutex_unlock(&vsock->tx_lock); > > mutex_lock(&vsock->rx_lock); > virtio_vsock_rx_fill(vsock); > vsock->rx_run = true; > mutex_unlock(&vsock->rx_lock); > > mutex_lock(&vsock->event_lock); > virtio_vsock_event_fill(vsock); > vsock->event_run = true; > mutex_unlock(&vsock->event_lock); > > if (virtio_has_feature(vdev, VIRTIO_VSOCK_F_SEQPACKET)) > vsock->seqpacket_allow = true; > > vdev->priv = vsock; > rcu_assign_pointer(the_virtio_vsock, vsock); > > mutex_unlock(&the_virtio_vsock_mutex); > > > I worry that this is not the only problem here: > seqpacket_allow and setting of vdev->priv at least after > device is active look suspicious. Right, so if you agree I'll move these before virtio_device_ready(). > E.g.: > > static void virtio_vsock_event_done(struct virtqueue *vq) > { > struct virtio_vsock *vsock = vq->vdev->priv; > > if (!vsock) > return; > queue_work(virtio_vsock_workqueue, &vsock->event_work); > } > > looks like it will miss events now they will be reported earlier. > One might say that since vq has been kicked it might send > interrupts earlier too so not a new problem, but > there's a chance device actually waits until DRIVER_OK > to start operating. Yes I see, should I break into 2 patches (one where I move the code already present and this one)? Maybe a single patch is fine since it's the complete solution. Thank you for the detailed explanation, StefanoTwo I think since movement can be backported to before the hardening effort.
Yep, maybe 3 since seqpacket was added later. Thanks, Stefano
