diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 51ecbae3c0bd..ed6902eb8d91 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -270,11 +270,11 @@ int iommu_probe_device(struct device *dev)
 	 */
 	mutex_lock(&group->mutex);
 	iommu_alloc_default_domain(group, dev);
-	mutex_unlock(&group->mutex);
 
 	if (group->default_domain) {
 		ret = __iommu_attach_device(group->default_domain, dev);
 		if (ret) {
+			mutex_unlock(&group->mutex);
 			iommu_group_put(group);
 			goto err_release;
 		}
@@ -282,6 +282,7 @@ int iommu_probe_device(struct device *dev)
 
 	iommu_create_device_direct_mappings(group, dev);
 
+	mutex_unlock(&group->mutex);
 	iommu_group_put(group);
 
 	if (ops->probe_finalize)