Re: 2.6.18-rc6-mm1: GPF loop on early boot

[Arjan van de Ven]

On Sun, 2006-09-10 at 10:32 +0200, Andi Kleen wrote:
> On Sunday 10 September 2006 11:35, Laurent Riffard wrote:
> > Le 08.09.2006 10:13, Andrew Morton a Ãcrit :
> > > ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.18-rc6/
> > >2.6.18-rc6-mm1/
> >
> > Hello,
> >
> > This kernel won't boot here: it starts a GPFs loop on
> > early boot. I attached a screenshot of the first GPF
> > (pause_on_oops=120 helped).
> 
> 
> It's lockdep's fault. This patch should fix it:
> 
> In general from my experience lockdep seems to be a dependency nightmare.
> It uses far too much infrastructure far too early. Should we always disable
> lockdep very early (before interrupts are turned on) instead? (early 
> everything is single threaded and will never have problems with lock 
> ordering)

lockdep starts somewhere in the middle; I doubt it's the only thing that
assumes that current is valid at that point.
>  /*
> - * Remove the lock to the list of currently held locks in a
> + * Remove the lock to the list of early_current()ly held locks in a
>   * potentially non-nested (out of order) manner. This is a
>   * relatively rare operation, as all the unlock APIs default
>   * to nested mode (which uses lock_release()):
> @@ -2227,7 +2231,7 @@ lock_release_non_nested(struct task_stru
>  	int i;
>  
>  	/*
> -	 * Check whether the lock exists in the current stack
> +	 * Check whether the lock exists in the early_current() stack
>  	 * of held locks:
>  	 */

??


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