Re: 2.6.25-rc: complete lockup on boot/start of X (bisected)

[Marcin Slusarz <marcin.slusarz@gmail.com>]

On Sun, Mar 23, 2008 at 08:09:01PM +0100, Peter Zijlstra wrote:
> On Sun, 2008-03-23 at 20:06 +0100, Peter Zijlstra wrote:
> > On Sun, 2008-03-23 at 19:46 +0100, Marcin Slusarz wrote:
> > 
> > > 4 different lockups:
> > > http://alan.umcs.lublin.pl/~mslusarz/kernel/2008.03.23-lockup/ 
> > 
> > Brilliant, these are extremely helpful.
> > 
> > What seems to happen is a classic xtime deadlock, doing a xtime
> > seq_readlock while holding a seq_writelock.
> > 
> > Only need to figure out _why_ that is happening....
> 
> Does your machine boot with the following patch applied:

Yes :). 20 boots and no lockup (10 with nmi_watchdog=2 and
10 with nmi_watchdog=2 and netconsole).

> 
> diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
> index 671af61..e300889 100644
> --- a/kernel/time/timekeeping.c
> +++ b/kernel/time/timekeeping.c
> @@ -190,9 +190,6 @@ static void change_clocksource(void)
>  	clocksource_calculate_interval(clock, NTP_INTERVAL_LENGTH);
>  
>  	tick_clock_notify();
> -
> -	printk(KERN_INFO "Time: %s clocksource has been installed.\n",
> -	       clock->name);
>  }
>  #else
>  static inline void change_clocksource(void) { }
> 
>