Commit 7bae49d4 authored Oct 29, 2007 by James Bottomley Committed by Ingo Molnar Oct 29, 2007

sched: fix incorrect assumption that cpu 0 exists



This patch:

commit 9b5b7751
Author: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Date:   Mon Oct 15 17:00:09 2007 +0200

    sched: clean up code under CONFIG_FAIR_GROUP_SCHED

Introduced an assumption of the existence of CPU0 via this line

cfs_rq = tg->cfs_rq[0];

If you have no CPU0, that will be NULL.  The fix seems to be just to
take whatever cfs_rq queue comes out of the for_each_possible_cpu()
loop, since they're all equally good for the destruction operation.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent 73a2bcb0

kernel/sched.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -7041,7 +7041,7 @@ static void free_sched_group(struct rcu_head *rhp)
		/* Destroy runqueue etc associated with a task group */
		void sched_destroy_group(struct task_group *tg)
		{
		struct cfs_rq *cfs_rq;
		struct cfs_rq *cfs_rq = NULL;
		int i;

		for_each_possible_cpu(i) {
		@@ -7049,7 +7049,7 @@ void sched_destroy_group(struct task_group *tg)
		list_del_rcu(&cfs_rq->leaf_cfs_rq_list);
		}

		cfs_rq = tg->cfs_rq[0];
		BUG_ON(!cfs_rq);

		/* wait for possible concurrent references to cfs_rqs complete */
		call_rcu(&cfs_rq->rcu, free_sched_group);

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