Re: 2.6.32-rc5-mmotm1101 - lockdep whinge during early boot

From: Thomas Gleixner
Date: Thu Nov 05 2009 - 10:55:30 EST


On Thu, 5 Nov 2009, Oleg Nesterov wrote:

> On 11/05, Oleg Nesterov wrote:
> >
> > On 11/05, Thomas Gleixner wrote:
> > >
> > > Hmm, we fixed all this lock madness in mainline already.
> > > clocksource_done_booting() does not longer call
> > > create_workqueue(). How got this code reverted in motm ?
> >
> > I don't understand this code at all. But this is what I see
> > in Linus's tree:
> >
> > clocksource_done_booting
> > clocksource_select
> > timekeeping_notify
> > stop_machine
> > stop_machine_create
> >
> >
> > OTOH, I don't see where native_cpu_up() path calls clocksource_change_rating(),
> > perhaps this was changed in -mm.
>
> I believe Martin knows the answer:
>
> On 11/05, Martin Schwidefsky wrote:
> >
> > That is imho caused by this patch snippet from the linux-next.patch from mmotd:
> >
> > diff -puN arch/x86/kernel/tsc.c~linux-next arch/x86/kernel/tsc.c
> > --- a/arch/x86/kernel/tsc.c~linux-next
> > +++ a/arch/x86/kernel/tsc.c
> > @@ -763,14 +763,12 @@ void mark_tsc_unstable(char *reason)
> > {
> > if (!tsc_unstable) {
> > tsc_unstable = 1;
> > - printk(KERN_INFO "Marking TSC unstable due to %s\n", reason);
> > + printk("Marking TSC unstable due to %s\n", reason);
> > /* Change only the rating, when not registered */
> > if (clocksource_tsc.mult)
> > - clocksource_mark_unstable(&clocksource_tsc);
> > - else {
> > - clocksource_tsc.flags |= CLOCK_SOURCE_UNSTABLE;
> > + clocksource_change_rating(&clocksource_tsc, 0);
>
> ^^^^^^^^^^^^^^^^^^^^^^^^^

Which basically reverts commit 7285dd7fd375763bfb8ab1ac9cf3f1206f503c16

Thanks,

tglx

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/