genirq: Check irq_data_get_irq_chip() return value before use

irq_data_get_irq_chip() can return NULL, however it is expected that this
never happens. If a buggy driver leads to NULL being returned from
irq_data_get_irq_chip(), warn about it instead of crashing the machine.

Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

To: linux-arm-kernel@lists.infradead.org

kernel/irq/manage.c

@@ -2619,6 +2619,8 @@ int __irq_get_irqchip_state(struct irq_data *data, enum irqchip_irq_state which,
 
 	do {
 		chip = irq_data_get_irq_chip(data);
+		if (WARN_ON_ONCE(!chip))
+			return -ENODEV;
 		if (chip->irq_get_irqchip_state)
 			break;
 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
@@ -2696,6 +2698,8 @@ int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
 
 	do {
 		chip = irq_data_get_irq_chip(data);
+		if (WARN_ON_ONCE(!chip))
+			return -ENODEV;
 		if (chip->irq_set_irqchip_state)
 			break;
 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY