From c350a04efd1c89cd256b2abc8f07a21d0d53ff24 Mon Sep 17 00:00:00 2001
From: Mike Galbraith <efault@gmx.de>
Date: Wed, 27 Jul 2011 17:14:55 +0200
Subject: [PATCH] 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>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1311779695.8691.2.camel@marge.simson.net
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
kernel/sched.c | 25 ++++++++++++-------------
1 file changed, 12 insertions(+), 13 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c
index b1e8f0eca1f9..cf427bb2b65e 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2843,20 +2843,24 @@ 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
@@ -2865,11 +2869,6 @@ 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;