Need to set task_cpu in wake_up_new_task to avoid a freshly affined task from
running on the wrong CPU.

We should use the indirect smt_schedule to avoid a rare crash at startup
before smt functions are stable.

We should _always_ resched in __setscheduler or we may miss an affinity change
till it's descheduled.

Go directly into __schedule() in __set_cpus_allowed_ptr to ensure we're
responsible for moving a task that has no affiity for the current CPU and
don't get preempted.

-ck


---
 kernel/sched/bfs.c |   16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

Index: linux-4.7-bfs/kernel/sched/bfs.c
===================================================================
--- linux-4.7-bfs.orig/kernel/sched/bfs.c
+++ linux-4.7-bfs/kernel/sched/bfs.c
@@ -1790,6 +1790,8 @@ void wake_up_new_task(struct task_struct
 
 	parent = p->parent;
 	rq = task_grq_lock(p, &flags);
+	if (unlikely(needs_other_cpu(p, task_cpu(p))))
+ 		set_task_cpu(p, cpumask_any(tsk_cpus_allowed(p)));
 	rq_curr = rq->curr;
 
 	/*
@@ -3372,7 +3374,7 @@ static void check_smt_siblings(struct rq
 		if (unlikely(!rq->online))
 			continue;
 		p = rq->curr;
-		if (!smt_should_schedule(p, this_rq)) {
+		if (!smt_schedule(p, this_rq)) {
 			set_tsk_need_resched(p);
 			smp_send_reschedule(other_cpu);
 		}
@@ -4021,9 +4023,7 @@ static void __setscheduler(struct task_s
 
 	if (task_running(p)) {
 		reset_rq_task(rq, p);
-		/* Resched only if we might now be preempted */
-		if (p->prio > oldprio || p->rt_priority < oldrtprio)
-			resched_task(p);
+		resched_task(p);
 	} else if (task_queued(p)) {
 		dequeue_task(p);
 		enqueue_task(p, rq);
@@ -5455,10 +5455,14 @@ static int __set_cpus_allowed_ptr(struct
 out:
 	if (queued && !cpumask_subset(new_mask, &old_mask))
 		try_preempt(p, rq);
+	if (running_wrong)
+		preempt_disable();
 	task_grq_unlock(&flags);
 
-	if (running_wrong)
-		preempt_schedule_common();
+	if (running_wrong) {
+		__schedule(true);
+		preempt_enable();
+	}
 
 	return ret;
 }