Merge tag 'cgroup-for-7.0-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup fixes from Tejun Heo:

 - Fix cgroup rmdir racing with dying tasks.

   Deferred task cgroup unlink introduced a window where cgroup.procs
   is empty but the cgroup is still populated, causing rmdir to fail
   with -EBUSY and selftest failures.

   Make rmdir wait for dying tasks to fully leave and fix selftests to
   not depend on synchronous populated updates.

 - Fix cpuset v1 task migration failure from empty cpusets under strict
   security policies.

   When CPU hotplug removes the last CPU from a v1 cpuset, tasks must be
   migrated to an ancestor without a security_task_setscheduler() check
   that would block the migration.

* tag 'cgroup-for-7.0-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup/cpuset: Skip security check for hotplug induced v1 task migration
  cgroup/cpuset: Simplify setsched decision check in task iteration loop of cpuset_can_attach()
  cgroup: Fix cgroup_drain_dying() testing the wrong condition
  selftests/cgroup: Don't require synchronous populated update on task exit
  cgroup: Wait for dying tasks to leave on rmdir

1 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index bb92f5c169ca..7f87399938fa 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -609,6 +609,9 @@ struct cgroup {
 	/* used to wait for offlining of csses */
 	wait_queue_head_t offline_waitq;
 
+	/* used by cgroup_rmdir() to wait for dying tasks to leave */
+	wait_queue_head_t dying_populated_waitq;
+
 	/* used to schedule release agent */
 	struct work_struct release_agent_work;