Re: [BUG] "sched: Remove rq->lock from the first half of ttwu()" locks up on ARM

Oleg Nesterov
2011-05-26T17:07:01Z

On 05/26, Peter Zijlstra wrote:
>
> @@ -2636,7 +2636,8 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags)
> * to spin on ->on_cpu if p is current, since that would
> * deadlock.
> */
> - if (p == current) {
> + if (cpu == smp_processor_id()) {
> + p->sched_contributes_to_load = 0;
> ttwu_queue(p, cpu);

Btw. I do not pretend I really understand se->vruntime, but in this
case we are doing enqueue_task() without ->task_waking(), however we
pass ENQUEUE_WAKING. Is it correct?

Oleg.