genirq: check chip->ack before calling

Impact: fix theoretical NULL dereference

The generic irq layer doesn't know whether irq_chip has ack routine on some
architectures or not. Upon that, before calling chip->ack, we should check
that it's not NULL.

Signed-off-by: Wang Chen <wangchen@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Wang Chen 2008-12-29 13:35:11 +08:00 committed by Ingo Molnar
parent 860cf8894b
commit efdc64f0c7

View File

@ -290,7 +290,8 @@ static inline void mask_ack_irq(struct irq_desc *desc, int irq)
desc->chip->mask_ack(irq);
else {
desc->chip->mask(irq);
desc->chip->ack(irq);
if (desc->chip->ack)
desc->chip->ack(irq);
}
}
@ -475,7 +476,8 @@ handle_edge_irq(unsigned int irq, struct irq_desc *desc)
kstat_incr_irqs_this_cpu(irq, desc);
/* Start handling the irq */
desc->chip->ack(irq);
if (desc->chip->ack)
desc->chip->ack(irq);
desc = irq_remap_to_desc(irq, desc);
/* Mark the IRQ currently in progress.*/