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SubjectRe: [patch] sched: fix broken SCHED_RESET_ON_FORK handling
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I knew that thing had been moved before.. see f83f9ac2.

On Wed, 2011-07-27 at 17:14 +0200, Mike Galbraith wrote:
> sched: fix broken SCHED_RESET_ON_FORK handling
>
> Setting child->prio = current->normal_prio _after_ SCHED_RESET_ON_FORK has
> been handled for an RT parent gives birth to a deranged mutant child with
> non-RT policy, but RT prio and sched_class.
>
> Move PI leakage protection up, always set priorities and weight, and if the
> child is leaving RT class, reset rt_priority to the proper value.
>
> Signed-off-by: Mike Galbraith <efault@gmx.de>
> Cc: <stable@kernel.org>
>
> diff --git a/kernel/sched.c b/kernel/sched.c
> index 0281f84..a3e65a0 100644
> --- a/kernel/sched.c
> +++ b/kernel/sched.c
> @@ -2804,19 +2804,23 @@ void sched_fork(struct task_struct *p)
> p->state = TASK_RUNNING;
>
> /*
> + * Make sure we do not leak PI boosting priority to the child.
> + */
> + p->prio = current->normal_prio;
> +
> + /*
> * Revert to default priority/policy on fork if requested.
> */
> if (unlikely(p->sched_reset_on_fork)) {
> - if (p->policy == SCHED_FIFO || p->policy == SCHED_RR) {
> + if (task_has_rt_policy(p)) {
> p->policy = SCHED_NORMAL;
> - p->normal_prio = p->static_prio;
> - }
> -
> - if (PRIO_TO_NICE(p->static_prio) < 0) {
> p->static_prio = NICE_TO_PRIO(0);
> - p->normal_prio = p->static_prio;
> - set_load_weight(p);
> - }
> + p->rt_priority = 0;
> + } else if (PRIO_TO_NICE(p->static_prio) < 0)
> + p->static_prio = NICE_TO_PRIO(0);
> +
> + p->prio = p->normal_prio = __normal_prio(p);
> + set_load_weight(p);
>
> /*
> * We don't need the reset flag anymore after the fork. It has
> @@ -2825,11 +2829,6 @@ void sched_fork(struct task_struct *p)
> p->sched_reset_on_fork = 0;
> }
>
> - /*
> - * Make sure we do not leak PI boosting priority to the child.
> - */
> - p->prio = current->normal_prio;
> -
> if (!rt_prio(p->prio))
> p->sched_class = &fair_sched_class;
>
>
>




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