diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 9e9acb05b..2a26f0273 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -214,6 +214,8 @@ int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
 	struct irq_chip *chip = irq_data_get_irq_chip(data);
 	int ret;
 
+	/* IRQs only run on the first CPU in the affinity mask; reflect that */
+	mask = cpumask_of(cpumask_first(mask));
 	ret = chip->irq_set_affinity(data, mask, force);
 	switch (ret) {
 	case IRQ_SET_MASK_OK: