irq, x86: fix lock status with numa_migrate_irq_desc
Eric Paris reported:
> I have an hp dl785g5 which is unable to successfully run
> 2.6.29-0.66.rc3.fc11.x86_64 or 2.6.29-rc2-next-20090126. During bootup
> (early in userspace daemons starting) I get the below BUG, which quickly
> renders the machine dead. I assume it is because sparse_irq_lock never
> gets released when the BUG kills that task.
Adjust lock sequence when migrating a descriptor with
CONFIG_NUMA_MIGRATE_IRQ_DESC enabled.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/irq/numa_migrate.c b/kernel/irq/numa_migrate.c
index ecf765c..acd8835 100644
--- a/kernel/irq/numa_migrate.c
+++ b/kernel/irq/numa_migrate.c
@@ -71,7 +71,7 @@
desc = irq_desc_ptrs[irq];
if (desc && old_desc != desc)
- goto out_unlock;
+ goto out_unlock;
node = cpu_to_node(cpu);
desc = kzalloc_node(sizeof(*desc), GFP_ATOMIC, node);
@@ -84,10 +84,15 @@
init_copy_one_irq_desc(irq, old_desc, desc, cpu);
irq_desc_ptrs[irq] = desc;
+ spin_unlock_irqrestore(&sparse_irq_lock, flags);
/* free the old one */
free_one_irq_desc(old_desc, desc);
+ spin_unlock(&old_desc->lock);
kfree(old_desc);
+ spin_lock(&desc->lock);
+
+ return desc;
out_unlock:
spin_unlock_irqrestore(&sparse_irq_lock, flags);