1 files changed, 3 insertions, 12 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 75aec12c78a..f24f724620d 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -4883,19 +4883,10 @@ void cgroup_post_fork(struct task_struct *child)
 	 */
 	if (use_task_css_set_links) {
 		write_lock(&css_set_lock);
-		if (list_empty(&child->cg_list)) {
-			/*
-			 * It's safe to use child->cgroups without task_lock()
-			 * here because we are protected through
-			 * threadgroup_change_begin() against concurrent
-			 * css_set change in cgroup_task_migrate(). Also
-			 * the task can't exit at that point until
-			 * wake_up_new_task() is called, so we are protected
-			 * against cgroup_exit() setting child->cgroup to
-			 * init_css_set.
-			 */
+		task_lock(child);
+		if (list_empty(&child->cg_list))
 			list_add(&child->cg_list, &child->cgroups->tasks);
-		}
+		task_unlock(child);
 		write_unlock(&css_set_lock);
 	}
 }