genirq: Unlock irq descriptor after errors

In irq_set_irqchip_state(), the irq descriptor is not unlocked after an
error is encountered. While that should never happen in practice, a buggy
driver may trigger it. This would result in a lockup, so fix it.

Fixes: 1d0326f352bb ("genirq: Check irq_data_get_irq_chip() return value before use")
Signed-off-by: Guenter Roeck <[e-mail]>
Signed-off-by: Thomas Gleixner <[e-mail]>
Cc: [e-mail]
Link: https://lore.kernel.org/r/[e-mail]

kernel/irq/manage.c

···
 
 	do {
 		chip = irq_data_get_irq_chip(data);
-		if (WARN_ON_ONCE(!chip))
-			return -ENODEV;
+		if (WARN_ON_ONCE(!chip)) {
+			err = -ENODEV;
+			goto out_unlock;
+		}
 		if (chip->irq_set_irqchip_state)
 			break;
 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
···
 	if (data)
 		err = chip->irq_set_irqchip_state(data, which, val);
 
+out_unlock:
 	irq_put_desc_busunlock(desc, flags);
 	return err;
 }