Eryu Guan <eg...@redhat.com> writes: > On Tue, Jul 04, 2017 at 04:26:11PM +1000, Michael Ellerman wrote: >> Eryu Guan <eg...@redhat.com> writes: >> > On Fri, Jun 30, 2017 at 08:07:02PM +1000, Michael Ellerman wrote: >> >> >> >> Can you try this patch and see if it changes anything? (with the debug >> >> still applied). >> > >> > This patch fixes the crash for me. After appliying this patch (with all >> > other debug patches still applied), kernel didn't print any warnings or >> > calltraces or debug messages. >> >> OK. It's not meant to fix it :) > > Understand. > >> >> I can't form any connection between your bisection result and that >> patch, nothing is making any sense TBH. >> >> What hardware are you on? And are you doing CPU hotplug or anything like >> that? > > It's a "PowerVM" guest (I'm not familiar with powerpc, I don't know what > does that mean..) running on Power8 host. I didn't do any CPU hotplug or > anything like that.
OK thanks. We might have to try and sync up on irc so we can debug this a bit faster. Can you try this hunk also? cheers diff --git a/kernel/workqueue.c b/kernel/workqueue.c index c74bf39ef764..7c55721b1f1d 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -3902,6 +3906,7 @@ static int alloc_and_link_pwqs(struct workqueue_struct *wq) "ordering guarantee broken for workqueue %s\n", wq->name); return ret; } else { + WARN_ON(cpumask_empty(unbound_std_wq_attrs[highpri]->cpumask)); return apply_workqueue_attrs(wq, unbound_std_wq_attrs[highpri]); } }