[Linux-ia64] Re: CPU hotplug boot change for IA64

[Rusty Russell <rusty@rustcorp.com.au>]

In message <20020802134915.ED77.K-SUGANUMA@mvj.biglobe.ne.jp> you write:
> Bit for CPU#0 on cpu_online_map was set at smp_boot_cpus() before.
> But on the 2.5.29, place of calling smp_boot_cpus() is changed to
> later timing and this seems to make a chance that smp_call_function()
> is called before setting cpu_online_map, (I guess.)
> In that case, smp_call_function won't return because num_online_cpus()
> returns 0 and the system will hang.
> 
> I have an experience of this problem only on a large system
> like Tiger, but it may occur on another system.
> 
> Rusty, I guess this modification should be needed for i386, too.

You should *not* be calling smp_call_function before smp_prepare_cpus.

I know kgdb can do this, but it's a special case.

Rusty.
--
  Anyone who quotes me in their sig is an idiot. -- Rusty Russell.