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

From: tip-bot for Paul Turner
Date: Tue Nov 30 2010 - 04:10:39 EST


Commit-ID: 822bc180a7f7a7bc5fcaaea195f41b487cc8cae8
Gitweb: http://git.kernel.org/tip/822bc180a7f7a7bc5fcaaea195f41b487cc8cae8
Author: Paul Turner <pjt@xxxxxxxxxx>
AuthorDate: Mon, 29 Nov 2010 16:55:40 -0800
Committer: Ingo Molnar <mingo@xxxxxxx>
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@xxxxxxxxxxxxxxxx>
Signed-off-by: Paul Turner <pjt@xxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
LKML-Reference: <20101130005740.080828123@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
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 */
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