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

[Thomas Gleixner <tglx@linutronix.de>]

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