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cpumask: fix bug in use cpumask_var_t in irq_desc

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Impact: fix bug where new irq_desc uses old cpumask pointers which are freed.

As Yinghai pointed out, init_copy_one_irq_desc() copies the old desc to
the new desc overwriting the cpumask pointers.  Since the old_desc and
the cpumask pointers are freed, then memory corruption will occur if
these old pointers are used.

Move the allocation of these pointers to after the copy.

Signed-off-by: Mike Travis <travis@sgi.com>
Cc: Yinghai Lu <yinghai@kernel.org>
This commit is contained in:
Mike Travis
2009-01-10 21:58:09 -08:00
committed by Ingo Molnar
parent 651f8118cf
commit 802bf931f2
3 changed files with 16 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
kernel/irq/numa_migrate.c
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@@ -38,16 +38,22 @@ static void free_kstat_irqs(struct irq_desc *old_desc, struct irq_desc *desc)
old_desc->kstat_irqs = NULL;
}
static void init_copy_one_irq_desc(int irq, struct irq_desc *old_desc,
static bool init_copy_one_irq_desc(int irq, struct irq_desc *old_desc,
struct irq_desc *desc, int cpu)
{
memcpy(desc, old_desc, sizeof(struct irq_desc));
if (!init_alloc_desc_masks(desc, cpu, false)) {
printk(KERN_ERR "irq %d: can not get new irq_desc cpumask "
"for migration.\n", irq);
return false;
}
spin_lock_init(&desc->lock);
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);
return true;
}
static void free_one_irq_desc(struct irq_desc *old_desc, struct irq_desc *desc)
@@ -83,15 +89,12 @@ static struct irq_desc *__real_move_irq_desc(struct irq_desc *old_desc,
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);
if (!init_copy_one_irq_desc(irq, old_desc, desc, cpu)) {
/* still use old one */
kfree(desc);
desc = old_desc;
goto out_unlock;
}
init_copy_one_irq_desc(irq, old_desc, desc, cpu);
irq_desc_ptrs[irq] = desc;