Re: v2.6.26-rc7: BUG: unable to handle kernel NULL pointer dereference

Rusty Russell
2008-06-23T03:28:39Z

On Monday 23 June 2008 02:29:07 Vegard Nossum wrote:
> And the (cpu < nr_cpu_ids) fails because the CPU has just been
> offlined (or failed to initialize, but it's the same thing), while
> NR_CPUS is the value that was compiled in as CONFIG_NR_CPUS (so the
> former check will always be true).
>
> I don't think it is valid to ask for a per_cpu() variable on a CPU
> which does not exist, though

Yes it is. As long as cpu_possible(cpu), per_cpu(cpu) is valid.

The number check should be removed: checking cpu_possible() is sufficient.

Hope that helps,
Rusty.