1 files changed, 21 insertions, 10 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 8b729c278b64..bcb1755f410a 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -4426,14 +4426,6 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
         list_add_tail_rcu(&cgrp->sibling, &cgrp->parent->children);
         root->number_of_cgroups++;
 
-        /* each css holds a ref to the cgroup's dentry and the parent css */
-        for_each_root_subsys(root, ss) {
-                struct cgroup_subsys_state *css = css_ar[ss->subsys_id];
-
-                dget(dentry);
-                css_get(css->parent);
-        }
-
         /* hold a ref to the parent's dentry */
         dget(parent->dentry);
 
@@ -4445,6 +4437,13 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
                 if (err)
                         goto err_destroy;
 
+                /* each css holds a ref to the cgroup's dentry and parent css */
+                dget(dentry);
+                css_get(css->parent);
+
+                /* mark it consumed for error path */
+                css_ar[ss->subsys_id] = NULL;
+
                 if (ss->broken_hierarchy && !ss->warned_broken_hierarchy &&
                     parent->parent) {
                         pr_warning("cgroup: %s (%d) created nested cgroup for controller \"%s\" which has incomplete hierarchy support. Nested cgroups may change behavior in the future.\n",
@@ -4491,6 +4490,14 @@ err_free_cgrp:
         return err;
 
 err_destroy:
+        for_each_root_subsys(root, ss) {
+                struct cgroup_subsys_state *css = css_ar[ss->subsys_id];
+
+                if (css) {
+                        percpu_ref_cancel_init(&css->refcnt);
+                        ss->css_free(css);
+                }
+        }
         cgroup_destroy_locked(cgrp);
         mutex_unlock(&cgroup_mutex);
         mutex_unlock(&dentry->d_inode->i_mutex);
@@ -4652,8 +4659,12 @@ static int cgroup_destroy_locked(struct cgroup *cgrp)
          * will be invoked to perform the rest of destruction once the
          * percpu refs of all css's are confirmed to be killed.
          */
-        for_each_root_subsys(cgrp->root, ss)
-                kill_css(cgroup_css(cgrp, ss));
+        for_each_root_subsys(cgrp->root, ss) {
+                struct cgroup_subsys_state *css = cgroup_css(cgrp, ss);
+
+                if (css)
+                        kill_css(css);
+        }
 
         /*
          * Mark @cgrp dead.  This prevents further task migration and child