Merge branch 'for-4.10-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup fix from Tejun Heo:
 "The cgroup creation path was getting the order of operations wrong and
  exposing cgroups which don't have their names set yet to controllers
  which can lead to NULL derefs.

  This contains the fix for the bug"

* 'for-4.10-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: don't online subsystems before cgroup_name/path() are operational

1 files changed, 5 insertions, 8 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 2ee9ec3051b2..688dd02af985 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -5221,6 +5221,11 @@ err_free_css:
         return ERR_PTR(err);
 }
 
+/*
+ * The returned cgroup is fully initialized including its control mask, but
+ * it isn't associated with its kernfs_node and doesn't have the control
+ * mask applied.
+ */
 static struct cgroup *cgroup_create(struct cgroup *parent)
 {
         struct cgroup_root *root = parent->root;
@@ -5288,11 +5293,6 @@ static struct cgroup *cgroup_create(struct cgroup *parent)
 
         cgroup_propagate_control(cgrp);
 
-        /* @cgrp doesn't have dir yet so the following will only create csses */
-        ret = cgroup_apply_control_enable(cgrp);
-        if (ret)
-                goto out_destroy;
-
         return cgrp;
 
 out_cancel_ref:
@@ -5300,9 +5300,6 @@ out_cancel_ref:
 out_free_cgrp:
         kfree(cgrp);
         return ERR_PTR(ret);
-out_destroy:
-        cgroup_destroy_locked(cgrp);
-        return ERR_PTR(ret);
 }
 
 static int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name,