Re: Oops on Power8 (was Re: [PATCH v2 1/7] workqueue: make workqueue available early during boot)

From: Tejun Heo
Date: Mon Oct 10 2016 - 09:14:40 EST

On Mon, Oct 10, 2016 at 09:02:53AM -0400, Tejun Heo wrote:
> Hello, Michael.
> On Mon, Oct 10, 2016 at 09:22:55PM +1100, Michael Ellerman wrote:
> > This patch seems to be causing one of my Power8 boxes not to boot.
> >
> > Specifically commit 3347fa092821 ("workqueue: make workqueue available
> > early during boot") in linux-next.
> >
> > If I revert this on top of next-20161005 then the machine boots again.
> >
> > I've attached the oops below. It looks like the cfs_rq of p->se is NULL?
> Hah, weird that it's arch dependent, or maybe it's just different
> config options. Most likely, it's caused by workqueue_init() call
> being moved too early. Can you please try the following patch and see
> whether the problem goes away?

And if it does, can you please post the boot log with kernel boot
option "initcall_debug=1" specified?