Merge branch 'for-3.13-fixes' into for-3.14

Pulling in as patches depending on 266ccd505e8a ("cgroup: fix
cgroup_create() error handling path") are scheduled.

Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index f9ae38a95af27e957ec9b7be47f90c90030aac43..2e5fbf9d63e92d74c144892ba09bdcc8f2649528 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -4162,14 +4162,6 @@ 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);
 
@@ -4181,6 +4173,13 @@ 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",
@@ -4227,6 +4226,14 @@ 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);
@@ -4387,8 +4394,12 @@ 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