diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 4ec8d2da..c108d3d 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1021,13 +1021,6 @@
 		}
 	}
 
-	/* Currently we don't handle adding/removing subsystems when
-	 * any child cgroups exist. This is theoretically supportable
-	 * but involves complex error handling, so it's being left until
-	 * later */
-	if (root->number_of_cgroups > 1)
-		return -EBUSY;
-
 	ret = cgroup_populate_dir(cgrp, added_mask);
 	if (ret)
 		return ret;
@@ -1373,6 +1366,12 @@
 		goto out_unlock;
 	}
 
+	/* remounting is not allowed for populated hierarchies */
+	if (root->number_of_cgroups > 1) {
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+
 	ret = rebind_subsystems(root, added_mask, removed_mask);
 	if (ret)
 		goto out_unlock;