diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 9b3ded518f83..2ae46fa6b3de 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -586,6 +586,9 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev)
 	 * All the ports in each a device should be in the same larbs.
 	 */
 	larbid = MTK_M4U_TO_LARB(fwspec->ids[0]);
+	if (larbid >= MTK_LARB_NR_MAX)
+		return ERR_PTR(-EINVAL);
+
 	for (i = 1; i < fwspec->num_ids; i++) {
 		larbidx = MTK_M4U_TO_LARB(fwspec->ids[i]);
 		if (larbid != larbidx) {
@@ -595,6 +598,9 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev)
 		}
 	}
 	larbdev = data->larb_imu[larbid].dev;
+	if (!larbdev)
+		return ERR_PTR(-EINVAL);
+
 	link = device_link_add(dev, larbdev,
 			       DL_FLAG_PM_RUNTIME | DL_FLAG_STATELESS);
 	if (!link)
diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c
index bc7ee90b9373..254530ad6c48 100644
--- a/drivers/iommu/mtk_iommu_v1.c
+++ b/drivers/iommu/mtk_iommu_v1.c
@@ -80,6 +80,7 @@
 /* MTK generation one iommu HW only support 4K size mapping */
 #define MT2701_IOMMU_PAGE_SHIFT			12
 #define MT2701_IOMMU_PAGE_SIZE			(1UL << MT2701_IOMMU_PAGE_SHIFT)
+#define MT2701_LARB_NR_MAX			3
 
 /*
  * MTK m4u support 4GB iova address space, and only support 4K page
@@ -457,6 +458,9 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev)
 
 	/* Link the consumer device with the smi-larb device(supplier) */
 	larbid = mt2701_m4u_to_larb(fwspec->ids[0]);
+	if (larbid >= MT2701_LARB_NR_MAX)
+		return ERR_PTR(-EINVAL);
+
 	for (idx = 1; idx < fwspec->num_ids; idx++) {
 		larbidx = mt2701_m4u_to_larb(fwspec->ids[idx]);
 		if (larbid != larbidx) {
@@ -467,6 +471,9 @@ static struct iommu_device *mtk_iommu_probe_device(struct device *dev)
 	}
 
 	larbdev = data->larb_imu[larbid].dev;
+	if (!larbdev)
+		return ERR_PTR(-EINVAL);
+
 	link = device_link_add(dev, larbdev,
 			       DL_FLAG_PM_RUNTIME | DL_FLAG_STATELESS);
 	if (!link)