Re: 2.5.2-pre2-3 SMP broken on UP boxen

[Alexander Viro]

On Wed, 23 Jan 2002, Ingo Molnar wrote:

> 
> On Wed, 23 Jan 2002, Zwane Mwaikambo wrote:
> 
> > 	My test box is a single proc machine running an SMP kernel. As
> > of 2.5.2-pre2 it panics on boot. [...]
> 
> the same on 2.5.3-pre3 as well?
> 
> > [...] The reason is kinda obvious, smp_processor_id() will always
> > return the same as global_irq_holder. How come we do this check now?
> 
> it should only be set when the current CPU has disabled global IRQs.

in arch/i386/kernel/smpboot.c:

@@ -1017,7 +1017,7 @@
 	boot_cpu_logical_apicid = logical_smp_processor_id();
 	map_cpu_to_boot_apicid(0, boot_cpu_apicid);
 
-	global_irq_holder = 0;
+	global_irq_holder = NO_PROC_ID;
 	current->cpu = 0;
 	smp_tune_scheduling();