diff --git a/virtio-devices/src/vhost_user/mod.rs b/virtio-devices/src/vhost_user/mod.rs
index 08daf48fb..81c48edf3 100644
--- a/virtio-devices/src/vhost_user/mod.rs
+++ b/virtio-devices/src/vhost_user/mod.rs
@@ -216,7 +216,7 @@ impl<S: VhostUserMasterReqHandler> VhostUserEpollHandler<S> {
         .map_err(|e| {
             EpollHelperError::IoError(std::io::Error::new(
                 std::io::ErrorKind::Other,
-                format!("failed connecting vhost-user backend{:?}", e),
+                format!("failed connecting vhost-user backend {:?}", e),
             ))
         })?;