Pull cgroup fixes from Tejun Heo:
"This pull request contains three fixes.
Two are reverts of task_lock() removal in cgroup fork path. The
optimizations incorrectly assumed that threadgroup_lock can protect
process forks (as opposed to thread creations) too. Further cleanup
of cgroup fork path is scheduled.
The third fixes cgroup emptiness notification loss."
* 'for-3.7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
Revert "cgroup: Remove task_lock() from cgroup_post_fork()"
Revert "cgroup: Drop task_lock(parent) on cgroup_fork()"
cgroup: notify_on_release may not be triggered in some cases