* [patch] sched: fix broken SCHED_RESET_ON_FORK handling
@ 2011-07-27 15:14 Mike Galbraith
2011-07-27 16:10 ` Mike Galbraith
2011-08-14 15:58 ` [tip:sched/core] " tip-bot for Mike Galbraith
0 siblings, 2 replies; 3+ messages in thread
From: Mike Galbraith @ 2011-07-27 15:14 UTC (permalink / raw)
To: LKML; +Cc: Peter Zijlstra, Ingo Molnar
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;
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [patch] sched: fix broken SCHED_RESET_ON_FORK handling
2011-07-27 15:14 [patch] sched: fix broken SCHED_RESET_ON_FORK handling Mike Galbraith
@ 2011-07-27 16:10 ` Mike Galbraith
2011-08-14 15:58 ` [tip:sched/core] " tip-bot for Mike Galbraith
1 sibling, 0 replies; 3+ messages in thread
From: Mike Galbraith @ 2011-07-27 16:10 UTC (permalink / raw)
To: LKML; +Cc: Peter Zijlstra, Ingo Molnar
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;
>
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread* [tip:sched/core] sched: fix broken SCHED_RESET_ON_FORK handling
2011-07-27 15:14 [patch] sched: fix broken SCHED_RESET_ON_FORK handling Mike Galbraith
2011-07-27 16:10 ` Mike Galbraith
@ 2011-08-14 15:58 ` tip-bot for Mike Galbraith
1 sibling, 0 replies; 3+ messages in thread
From: tip-bot for Mike Galbraith @ 2011-08-14 15:58 UTC (permalink / raw)
To: linux-tip-commits
Cc: linux-kernel, hpa, mingo, a.p.zijlstra, efault, tglx, mingo
Commit-ID: c350a04efd1c89cd256b2abc8f07a21d0d53ff24
Gitweb: http://git.kernel.org/tip/c350a04efd1c89cd256b2abc8f07a21d0d53ff24
Author: Mike Galbraith <efault@gmx.de>
AuthorDate: Wed, 27 Jul 2011 17:14:55 +0200
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Sun, 14 Aug 2011 12:00:43 +0200
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 files changed, 12 insertions(+), 13 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c
index b1e8f0e..cf427bb 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2844,19 +2844,23 @@ 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
@@ -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;
^ permalink raw reply related [flat|nested] 3+ messages in thread
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2011-07-27 15:14 [patch] sched: fix broken SCHED_RESET_ON_FORK handling Mike Galbraith
2011-07-27 16:10 ` Mike Galbraith
2011-08-14 15:58 ` [tip:sched/core] " tip-bot for Mike Galbraith
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