* 1) running (obviously), or
* 2) cannot be migrated to this CPU due to cpus_allowed, or
* 3) are cache-hot on their current CPU.
+ * 4) p->pi_lock is held.
*/
if (!cpumask_test_cpu(this_cpu, tsk_cpus_allowed(p))) {
schedstat_inc(p, se.statistics.nr_failed_migrations_affine);
return 0;
}
+ /*
+ * rt -> fair class change may be in progress. If we sneak in should
+ * double_lock_balance() release rq->lock, and move the task, we will
+ * cause switched_to_fair() to meet a passed but no longer valid rq.
+ */
+ if (raw_spin_is_locked(&p->pi_lock))
+ return 0;
+
/*
* Aggressive migration if:
* 1) task is cache cold, or