On Wed, Jan 7, 2009 at 11:58 AM, Mike Travis [off-list ref] wrote:
| --- linux-2.6-for-ingo.orig/kernel/irq/numa_migrate.c
| +++ linux-2.6-for-ingo/kernel/irq/numa_migrate.c
| @@ -46,6 +46,7 @@ static void init_copy_one_irq_desc(int i
| 	desc->cpu = cpu;
| 	lockdep_set_class(&desc->lock, &irq_desc_lock_class);
| 	init_copy_kstat_irqs(old_desc, desc, cpu, nr_cpu_ids);
|+	init_copy_desc_masks(old_desc, desc);
| 	arch_init_copy_chip_data(old_desc, desc, cpu);
| }
|
|@@ -76,11 +77,20 @@ static struct irq_desc *__real_move_irq_
| 	node = cpu_to_node(cpu);
| 	desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
| 	if (!desc) {
|-		printk(KERN_ERR "irq %d: can not get new irq_desc for migration.\n", irq);
|+		printk(KERN_ERR "irq %d: can not get new irq_desc "
|+				"for migration.\n", irq);
| 		/* still use old one */
| 		desc = old_desc;
| 		goto out_unlock;
| 	}
|+	if (!init_alloc_desc_masks(desc, node, false)) {
|+		printk(KERN_ERR "irq %d: can not get new irq_desc cpumask "
|+				"for migration.\n", irq);
|+		/* still use old one */
|+		kfree(desc);
|+		desc = old_desc;
|+		goto out_unlock;
|+	}
| 	init_copy_one_irq_desc(irq, old_desc, desc, cpu);

desc new mask_var (allocated) aka the pointer is overwritten here...
you may need to calling move init_alloc_desc_masks() into
init_copy_one_irq_desc()

| 	irq_desc_ptrs[irq] = desc;

YH