diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 3f1029c0825e..ade41d336a04 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -3149,6 +3149,11 @@ int iommu_device_use_default_domain(struct device *dev)
 		return 0;
 
 	mutex_lock(&group->mutex);
+	/* We may race against bus_iommu_probe() finalising groups here */
+	if (!group->default_domain) {
+		ret = -EPROBE_DEFER;
+		goto unlock_out;
+	}
 	if (group->owner_cnt) {
 		if (group->owner || !iommu_is_default_domain(group) ||
 		    !xa_empty(&group->pasid_array)) {