diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index ac4731d13a83..5b73d36e4359 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -3084,6 +3084,11 @@ 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->domain != group->default_domain || group->owner ||
 		    !xa_empty(&group->pasid_array)) {