iommu/mediatek: Check return value after calling platform_get_resource()

[ Upstream commit 73b6924cdebc899de9b719e1319aa86c6bed4acf ]

platform_get_resource() may return NULL pointer, we need check its
return value to avoid null-ptr-deref in resource_size().

Fixes: 42d57fc58aeb ("iommu/mediatek: Initialise/Remove for multi bank dev")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Link: https://lore.kernel.org/r/20221029103550.3774365-1-yangyingliang@huawei.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 2ab2ecf..2d14dc8 100644 (file)
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -1173,6 +1173,8 @@ static int mtk_iommu_probe(struct platform_device *pdev)
 
        banks_num = data->plat_data->banks_num;
        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       if (!res)
+               return -EINVAL;
        if (resource_size(res) < banks_num * MTK_IOMMU_BANK_SZ) {
                dev_err(dev, "banknr %d. res %pR is not enough.\n", banks_num, res);
                return -EINVAL;