1 files changed, 11 insertions, 9 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index dcb06e181ce4..d5af128ec1ec 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -157,14 +157,13 @@ static int cgroup_root_count;
 static DEFINE_IDR(cgroup_hierarchy_idr);
 
 /*
- * Assign a monotonically increasing serial number to cgroups.  It
- * guarantees cgroups with bigger numbers are newer than those with smaller
- * numbers.  Also, as cgroups are always appended to the parent's
- * ->children list, it guarantees that sibling cgroups are always sorted in
- * the ascending serial number order on the list.  Protected by
- * cgroup_mutex.
+ * Assign a monotonically increasing serial number to csses.  It guarantees
+ * cgroups with bigger numbers are newer than those with smaller numbers.
+ * Also, as csses are always appended to the parent's ->children list, it
+ * guarantees that sibling csses are always sorted in the ascending serial
+ * number order on the list.  Protected by cgroup_mutex.
  */
-static u64 cgroup_serial_nr_next = 1;
+static u64 css_serial_nr_next = 1;
 
 /* This flag indicates whether tasks in the fork and exit paths should
  * check for fork/exit handlers to call. This avoids us having to do
@@ -3133,7 +3132,7 @@ css_next_child(struct cgroup_subsys_state *pos_css,
                 next = list_entry_rcu(pos->self.sibling.next, struct cgroup, self.sibling);
         } else {
                 list_for_each_entry_rcu(next, &cgrp->self.children, self.sibling)
-                        if (next->serial_nr > pos->serial_nr)
+                        if (next->self.serial_nr > pos->self.serial_nr)
                                 break;
         }
 
@@ -4168,6 +4167,8 @@ static void css_release(struct percpu_ref *ref)
 static void init_and_link_css(struct cgroup_subsys_state *css,
                               struct cgroup_subsys *ss, struct cgroup *cgrp)
 {
+        lockdep_assert_held(&cgroup_mutex);
+
         cgroup_get(cgrp);
 
         memset(css, 0, sizeof(*css));
@@ -4175,6 +4176,7 @@ static void init_and_link_css(struct cgroup_subsys_state *css,
         css->ss = ss;
         INIT_LIST_HEAD(&css->sibling);
         INIT_LIST_HEAD(&css->children);
+        css->serial_nr = css_serial_nr_next++;
 
         if (cgroup_parent(cgrp)) {
                 css->parent = cgroup_css(cgroup_parent(cgrp), ss);
@@ -4348,7 +4350,7 @@ static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name,
          */
         kernfs_get(kn);
 
-        cgrp->serial_nr = cgroup_serial_nr_next++;
+        cgrp->self.serial_nr = css_serial_nr_next++;
 
         /* allocation complete, commit to creation */
         list_add_tail_rcu(&cgrp->self.sibling, &cgroup_parent(cgrp)->self.children);