[PATCH V3 07/17] genirq: Ensure IRQ descriptor is valid when setting-up the IRQ

From: Jon Hunter
Date: Wed May 04 2016 - 12:31:02 EST

In the function, setup_irq(), we don't check that the descriptor
returned from irq_to_desc() is valid before we start using it. For
example chip_bus_lock() called from setup_irq(), assumes that the
descriptor pointer is valid and doesn't check before dereferencing it.

In many other functions including setup/free_percpu_irq() we do check
that the descriptor returned is not NULL and therefore add the same test
to setup_irq() to ensure the descriptor returned is valid.

Signed-off-by: Jon Hunter <jonathanh@xxxxxxxxxx>
kernel/irq/manage.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index b2a93a37f772..eaedeb74b49d 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1414,7 +1414,7 @@ int setup_irq(unsigned int irq, struct irqaction *act)
int retval;
struct irq_desc *desc = irq_to_desc(irq);

- if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
+ if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
return -EINVAL;
retval = __setup_irq(irq, desc, act);