[patch] sched: fix unregister_fair_sched_group

[patch] sched: fix unregister_fair_sched_group

[Paul Turner]

[-- Attachment #1: sched-fix_unregister.patch --]
[-- Type: text/plain, Size: 1069 bytes --]

In the flipping and flopping between calling unregister_fair_sched_group on a
per-cpu versus per-group basis we ended up in a bad state.

Remove from the list for the passed cpu as opposed to some arbitrary index.

(This fixes explosions w/ autogroup as well as a group creation/destruction 
stress test)

Signed-off-by: Paul Turner <pjt@google.com>
---
 kernel/sched.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

Index: tip/kernel/sched.c
===================================================================
--- tip.orig/kernel/sched.c
+++ tip/kernel/sched.c
@@ -8097,7 +8097,6 @@ static inline void unregister_fair_sched
 {
 	struct rq *rq = cpu_rq(cpu);
 	unsigned long flags;
-	int i;
 
 	/*
 	* Only empty task groups can be destroyed; so we can speculatively
@@ -8107,7 +8106,7 @@ static inline void unregister_fair_sched
 		return;
 
 	raw_spin_lock_irqsave(&rq->lock, flags);
-	list_del_leaf_cfs_rq(tg->cfs_rq[i]);
+	list_del_leaf_cfs_rq(tg->cfs_rq[cpu]);
 	raw_spin_unlock_irqrestore(&rq->lock, flags);
 }
 #else /* !CONFG_FAIR_GROUP_SCHED */

[tip:sched/core] sched: Fix unregister_fair_sched_group()

[tip-bot for Paul Turner]

Commit-ID:  822bc180a7f7a7bc5fcaaea195f41b487cc8cae8
Gitweb:     http://git.kernel.org/tip/822bc180a7f7a7bc5fcaaea195f41b487cc8cae8
Author:     Paul Turner <pjt@google.com>
AuthorDate: Mon, 29 Nov 2010 16:55:40 -0800
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Tue, 30 Nov 2010 10:07:10 +0100

sched: Fix unregister_fair_sched_group()

In the flipping and flopping between calling
unregister_fair_sched_group() on a per-cpu versus per-group basis
we ended up in a bad state.

Remove from the list for the passed cpu as opposed to some
arbitrary index.

( This fixes explosions w/ autogroup as well as a group
  creation/destruction stress test. )

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <20101130005740.080828123@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 kernel/sched.c |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/kernel/sched.c b/kernel/sched.c
index 35a6373..66ef579 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -8085,7 +8085,6 @@ static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
 {
 	struct rq *rq = cpu_rq(cpu);
 	unsigned long flags;
-	int i;
 
 	/*
 	* Only empty task groups can be destroyed; so we can speculatively
@@ -8095,7 +8094,7 @@ static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
 		return;
 
 	raw_spin_lock_irqsave(&rq->lock, flags);
-	list_del_leaf_cfs_rq(tg->cfs_rq[i]);
+	list_del_leaf_cfs_rq(tg->cfs_rq[cpu]);
 	raw_spin_unlock_irqrestore(&rq->lock, flags);
 }
 #else /* !CONFG_FAIR_GROUP_SCHED */