diff --git a/src/core/mount-setup.c b/src/core/mount-setup.c
index 6140f56d83..fe50fb19da 100644
--- a/src/core/mount-setup.c
+++ b/src/core/mount-setup.c
@@ -315,6 +315,7 @@ int mount_cgroup_controllers(char ***join_controllers) {
                 p.type = "cgroup";
                 p.options = options;
                 p.flags = MS_NOSUID|MS_NOEXEC|MS_NODEV;
+                p.mode = MNT_IN_CONTAINER;
 
                 r = mount_one(&p, true);
                 free(controller);