1 files changed, 3 insertions, 12 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 75aec12c78a0..f24f724620dd 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);
         }
 }