On 11/30, Roman Gushchin wrote:

+void cgroup_enter_frozen(void)
+{
+	if (!current->frozen) {
+		struct cgroup *cgrp;
+
+		spin_lock_irq(&css_set_lock);
+		current->frozen = true;
+		cgrp = task_dfl_cgroup(current);
+		cgrp->freezer.nr_frozen_tasks++;
+		WARN_ON_ONCE(cgrp->freezer.nr_frozen_tasks >
+			     cgrp->freezer.nr_tasks_to_freeze);
+		cgroup_update_frozen(cgrp, true);
+		spin_unlock_irq(&css_set_lock);
+	}
+
+	__set_current_state(TASK_INTERRUPTIBLE);
+	schedule();
+	__set_current_state(TASK_RUNNING);

forgot to mention, schedule() always returns in TASK_RUNNING, so the 2nd
__set_current_state() is pointless.

Oleg.