diff --git a/Documentation/cgroup-v2.txt b/Documentation/cgroup-v2.txt
index cb9ea281ab72..dec5afdaa36d 100644
--- a/Documentation/cgroup-v2.txt
+++ b/Documentation/cgroup-v2.txt
@@ -274,8 +274,9 @@ thread mode, the following conditions must be met.
 - As the cgroup will join the parent's resource domain.  The parent
   must either be a valid (threaded) domain or a threaded cgroup.
 
-- The cgroup must be empty.  No enabled controllers, child cgroups or
-  processes.
+- When the parent is an unthreaded domain, it must not have any domain
+  controllers enabled or populated domain children.  The root is
+  exempt from this requirement.
 
 Topology-wise, a cgroup can be in an invalid state.  Please consider
 the following toplogy::
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index e9a377dc5bdb..e0a558c4d358 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -3146,13 +3146,6 @@ static int cgroup_enable_threaded(struct cgroup *cgrp)
 	    !cgroup_can_be_thread_root(dom_cgrp))
 		return -EOPNOTSUPP;
 
-	/*
-	 * Allow enabling thread mode only on empty cgroups to avoid
-	 * implicit migrations and recursive operations.
-	 */
-	if (cgroup_has_tasks(cgrp) || css_has_online_children(&cgrp->self))
-		return -EBUSY;
-
 	/*
 	 * The following shouldn't cause actual migrations and should
 	 * always succeed.