Subject: Re: Fw: 2.6.16 crashes when running numastat on p575

From: Andi Kleen <[email-masked]>
Date: Mon, 3 Apr 2006 13:49:02 +0200

On Monday 03 April 2006 07:15, Paul Jackson wrote:
> -		for (cpu = 0; cpu < NR_CPUS; cpu++) {
> +		for_each_online_cpu(cpu) {
> 
> Idle curiosity -- what keeps a cpu from going offline during
> this scan, and leaving us with the same crash as before?

CPU hotdown uses RCU like techniques to avoid this. Only potential
problem could be on a preemptive kernel, but I hope nobody tries
cpu unplug on such a beast. The later could be probably fixed
with a rcu_read_lock() or somesuch.

-Andi