Stefano Garzarella
2023-Oct-19 08:54 UTC
[PATCH] vsock: initialize the_virtio_vsock before using VQs
On Wed, Oct 18, 2023 at 09:32:47PM +0300, Alexandru Matei wrote:>Once VQs are filled with empty buffers and we kick the host, it can send >connection requests. If 'the_virtio_vsock' is not initialized before, >replies are silently dropped and do not reach the host.Are replies really dropped or we just miss the notification? Could the reverse now happen, i.e., the guest wants to send a connection request, finds the pointer assigned but can't use virtqueues because they haven't been initialized yet? Perhaps to avoid your problem, we could just queue vsock->rx_work at the bottom of the probe to see if anything was queued in the meantime. Nit: please use "vsock/virtio" to point out that this problem is of the virtio transport. Thanks, Stefano> >Fixes: 0deab087b16a ("vsock/virtio: use RCU to avoid use-after-free on the_virtio_vsock") >Signed-off-by: Alexandru Matei <alexandru.matei at uipath.com> >--- > net/vmw_vsock/virtio_transport.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > >diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c >index e95df847176b..eae0867133f8 100644 >--- a/net/vmw_vsock/virtio_transport.c >+++ b/net/vmw_vsock/virtio_transport.c >@@ -658,12 +658,13 @@ static int virtio_vsock_probe(struct virtio_device *vdev) > vsock->seqpacket_allow = true; > > vdev->priv = vsock; >+ rcu_assign_pointer(the_virtio_vsock, vsock); > > ret = virtio_vsock_vqs_init(vsock); >- if (ret < 0) >+ if (ret < 0) { >+ rcu_assign_pointer(the_virtio_vsock, NULL); > goto out; >- >- rcu_assign_pointer(the_virtio_vsock, vsock); >+ } > > mutex_unlock(&the_virtio_vsock_mutex); > >-- >2.34.1 > >