Revert "cgroup: avoid attaching a cgroup root to two different superblocks"

This reverts commit bfb0b80db5f9dca5ac0a5fd0edb765ee555e5a8e.

Andrei reports CRIU test hangs with the patch applied.  The bug fixed
by the patch isn't too likely to trigger in actual uses.  Revert the
patch for now.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Andrei Vagin <avagin@virtuozzo.com>
Link: http://lkml.kernel.org/r/20170414232737.GC20350@outlook.office365.com
1 file changed