1 files changed, 26 insertions, 18 deletions

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 16fe1c6cad35..502769b2683c 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -5900,17 +5900,20 @@ static struct cgroup *cgroup_get_from_file(struct file *f)
 
 /**
  * cgroup_can_fork - called on a new task before the process is exposed
- * @child: the task in question.
+ * @child: the child process
  *
- * This calls the subsystem can_fork() callbacks. If the can_fork() callback
- * returns an error, the fork aborts with that error code. This allows for
- * a cgroup subsystem to conditionally allow or deny new forks.
+ * This calls the subsystem can_fork() callbacks. If the cgroup_can_fork()
+ * callback returns an error, the fork aborts with that error code. This
+ * allows for a cgroup subsystem to conditionally allow or deny new forks.
  */
 int cgroup_can_fork(struct task_struct *child)
+	__acquires(&cgroup_threadgroup_rwsem) __releases(&cgroup_threadgroup_rwsem)
 {
 	struct cgroup_subsys *ss;
 	int i, j, ret;
 
+	cgroup_threadgroup_change_begin(current);
+
 	do_each_subsys_mask(ss, i, have_canfork_callback) {
 		ret = ss->can_fork(child);
 		if (ret)
@@ -5927,17 +5930,20 @@ out_revert:
 			ss->cancel_fork(child);
 	}
 
+	cgroup_threadgroup_change_end(current);
+
 	return ret;
 }
 
 /**
- * cgroup_cancel_fork - called if a fork failed after cgroup_can_fork()
- * @child: the task in question
- *
- * This calls the cancel_fork() callbacks if a fork failed *after*
- * cgroup_can_fork() succeded.
- */
+  * cgroup_cancel_fork - called if a fork failed after cgroup_can_fork()
+  * @child: the child process
+  *
+  * This calls the cancel_fork() callbacks if a fork failed *after*
+  * cgroup_can_fork() succeded.
+  */
 void cgroup_cancel_fork(struct task_struct *child)
+	__releases(&cgroup_threadgroup_rwsem)
 {
 	struct cgroup_subsys *ss;
 	int i;
@@ -5945,19 +5951,19 @@ void cgroup_cancel_fork(struct task_struct *child)
 	for_each_subsys(ss, i)
 		if (ss->cancel_fork)
 			ss->cancel_fork(child);
+
+	cgroup_threadgroup_change_end(current);
 }
 
 /**
- * cgroup_post_fork - called on a new task after adding it to the task list
- * @child: the task in question
- *
- * Adds the task to the list running through its css_set if necessary and
- * call the subsystem fork() callbacks.  Has to be after the task is
- * visible on the task list in case we race with the first call to
- * cgroup_task_iter_start() - to guarantee that the new task ends up on its
- * list.
+ * cgroup_post_fork - finalize cgroup setup for the child process
+ * @child: the child process
+ *
+ * Attach the child process to its css_set calling the subsystem fork()
+ * callbacks.
  */
 void cgroup_post_fork(struct task_struct *child)
+	__releases(&cgroup_threadgroup_rwsem)
 {
 	struct cgroup_subsys *ss;
 	struct css_set *cset;
@@ -6003,6 +6009,8 @@ void cgroup_post_fork(struct task_struct *child)
 	do_each_subsys_mask(ss, i, have_fork_callback) {
 		ss->fork(child);
 	} while_each_subsys_mask();
+
+	cgroup_threadgroup_change_end(current);
 }
 
 /**