Re: [git pull] scheduler updates for v2.6.24

[Ingo Molnar <mingo@elte.hu>]

* Andrew Morton <akpm@linux-foundation.org> wrote:

> On Mon, 15 Oct 2007 16:17:23 +0200
> Ingo Molnar <mingo@elte.hu> wrote:
> 
> > Linus, please pull the latest scheduler git tree from:
> > 
> >    git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched.git
> 
> Did Paul Jackson's crash get fixed?

yes - that crash was a showstopper that was holding up the pull request 
for 2 days. Paul bisected it down to the culprit and the fix was to do 
this in wake_up_new_task():

-       if (!p->sched_class->task_new || !current->se.on_rq) {
+       if (!p->sched_class->task_new || !current->se.on_rq || !rq->cfs.curr) {

(during early bootup the cfs_rq has no curr pointer yet.) It's not clear 
why this race did not trigger earlier. (and the two checks can probably 
be consolidated into a single "!rq->cfs.curr" condition.)

	Ingo