From a3f1a29e4d773c9a7f2236c623d7567587c1204d Mon Sep 17 00:00:00 2001 From: Alexandru Matei Date: Tue, 24 Oct 2023 22:17:42 +0300 Subject: [PATCH 7/7] vsock/virtio: initialize the_virtio_vsock before using VQs 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. virtio_transport_send_pkt() can queue packets once the_virtio_vsock is set, but they won't be processed until vsock->tx_run is set to true. We queue vsock->send_pkt_work when initialization finishes to send those packets queued earlier. Fixes: 0deab087b16a ("vsock/virtio: use RCU to avoid use-after-free on the_virtio_vsock") Signed-off-by: Alexandru Matei Reviewed-by: Stefano Garzarella Link: https://lore.kernel.org/r/20231024191742.14259-1-alexandru.matei@uipath.com Signed-off-by: Jakub Kicinski --- net/vmw_vsock/virtio_transport.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c index 793c4b1325f1..25a9f03f0027 100644 --- a/net/vmw_vsock/virtio_transport.c +++ b/net/vmw_vsock/virtio_transport.c @@ -567,6 +567,11 @@ static int virtio_vsock_vqs_init(struct virtio_vsock *vsock) virtio_device_ready(vdev); + return 0; +} + +static void virtio_vsock_vqs_start(struct virtio_vsock *vsock) +{ mutex_lock(&vsock->tx_lock); vsock->tx_run = true; mutex_unlock(&vsock->tx_lock); @@ -581,7 +586,16 @@ static int virtio_vsock_vqs_init(struct virtio_vsock *vsock) vsock->event_run = true; mutex_unlock(&vsock->event_lock); - return 0; + /* virtio_transport_send_pkt() can queue packets once + * the_virtio_vsock is set, but they won't be processed until + * vsock->tx_run is set to true. We queue vsock->send_pkt_work + * when initialization finishes to send those packets queued + * earlier. + * We don't need to queue the other workers (rx, event) because + * as long as we don't fill the queues with empty buffers, the + * host can't send us any notification. + */ + queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work); } static void virtio_vsock_vqs_del(struct virtio_vsock *vsock) @@ -681,6 +695,7 @@ static int virtio_vsock_probe(struct virtio_device *vdev) goto out; rcu_assign_pointer(the_virtio_vsock, vsock); + virtio_vsock_vqs_start(vsock); mutex_unlock(&the_virtio_vsock_mutex); @@ -753,6 +768,7 @@ static int virtio_vsock_restore(struct virtio_device *vdev) goto out; rcu_assign_pointer(the_virtio_vsock, vsock); + virtio_vsock_vqs_start(vsock); out: mutex_unlock(&the_virtio_vsock_mutex); -- 2.34.1