Add the missing larb count sanity check to avoid writing beyond a fixed
sized array in case of a malformed devicetree.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/iommu/mtk_iommu_v1.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c
index 44b965a2db92..55d6615a41a9 100644
--- a/drivers/iommu/mtk_iommu_v1.c
+++ b/drivers/iommu/mtk_iommu_v1.c
@@ -643,6 +643,9 @@ static int mtk_iommu_v1_probe(struct platform_device *pdev)
 	if (larb_nr < 0)
 		return larb_nr;
 
+	if (larb_nr > MTK_LARB_NR_MAX)
+		return -EINVAL;
+
 	for (i = 0; i < larb_nr; i++) {
 		struct device_node *larbnode;
 		struct platform_device *plarbdev;
-- 
2.49.1