From: Stefano Garzarella <sgarzare@redhat.com> commit ce7536bc7398e2ae552d2fabb7e0e371a9f1fe46 upstream. If the socket is closed or is being released, some resources used by virtio_transport_space_update() such as 'vsk->trans' may be released. To avoid a use after free bug we should only update the available credit when we are sure the socket is still open and we have the lock held. Fixes: 06a8fc78367d ("VSOCK: Introduce virtio_vsock_common.ko") Signed-off-by: Stefano Garzarella <sgarzare@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Link: https://lore.kernel.org/r/20210208144454.84438-1-sgarzare@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/vmw_vsock/virtio_transport_common.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c index 4ae824ea3f281..d197a5f05edc5 100644 --- a/net/vmw_vsock/virtio_transport_common.c +++ b/net/vmw_vsock/virtio_transport_common.c @@ -1075,10 +1075,10 @@ void virtio_transport_recv_pkt(struct virtio_transport *t, vsk = vsock_sk(sk); - space_available = virtio_transport_space_update(sk, pkt); - lock_sock(sk); + space_available = virtio_transport_space_update(sk, pkt); + /* Check if sk has been released before lock_sock */ if (sk->sk_shutdown == SHUTDOWN_MASK) { (void)virtio_transport_reset_no_sock(t, pkt); -- 2.25.1