Merge tag 'cgroup-for-7.0-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup fixes from Tejun Heo:

 - Fix circular locking dependency in cpuset partition code by
   deferring housekeeping_update() calls to a workqueue instead
   of calling them directly under cpus_read_lock

 - Fix null-ptr-deref in rebuild_sched_domains_cpuslocked() when
   generate_sched_domains() returns NULL due to kmalloc failure

 - Fix incorrect cpuset behavior for effective_xcpus in
   partition_xcpus_del() and cpuset_update_tasks_cpumask()
   in update_cpumasks_hier()

 - Fix race between task migration and cgroup iteration

* tag 'cgroup-for-7.0-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup/cpuset: fix null-ptr-deref in rebuild_sched_domains_cpuslocked
  cgroup/cpuset: Call housekeeping_update() without holding cpus_read_lock
  cgroup/cpuset: Defer housekeeping_update() calls from CPU hotplug to workqueue
  cgroup/cpuset: Move housekeeping_update()/rebuild_sched_domains() together
  kselftest/cgroup: Simplify test_cpuset_prs.sh by removing "S+" command
  cgroup/cpuset: Set isolated_cpus_updating only if isolated_cpus is changed
  cgroup/cpuset: Clarify exclusion rules for cpuset internal variables
  cgroup/cpuset: Fix incorrect use of cpuset_update_tasks_cpumask() in update_cpumasks_hier()
  cgroup/cpuset: Fix incorrect change to effective_xcpus in partition_xcpus_del()
  cgroup: fix race between task migration and iteration

Author: torvalds

kernel/cgroup/cgroup.c

@@ -2608,6 +2608,7 @@ static void cgroup_migrate_add_task(struct task_struct *task,
 
 	mgctx->tset.nr_tasks++;
 
+	css_set_skip_task_iters(cset, task);
 	list_move_tail(&task->cg_list, &cset->mg_tasks);
 	if (list_empty(&cset->mg_node))
 		list_add_tail(&cset->mg_node,