drm/rockchip: vop: fix possible null-ptr-deref in vop_bind()

[ Upstream commit f8c242908ad15bbd604d3bcb54961b7d454c43f8 ]

It will cause null-ptr-deref in resource_size(), if platform_get_resource()
returns NULL, move calling resource_size() after devm_ioremap_resource() that
will check 'res' to avoid null-ptr-deref.

Fixes: 2048e3286f34 ("drm: rockchip: Add basic drm driver")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220422032854.2995175-1-yangyingliang@huawei.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
index 7010424b2f89dca6ad96d92b3c89fbebd06d1ca5..80a65eaed0be95bb9dac15042eebd526de304bce 100644 (file)
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
@@ -1551,10 +1551,10 @@ static int vop_bind(struct device *dev, struct device *master, void *data)
        vop_win_init(vop);
 
        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-       vop->len = resource_size(res);
        vop->regs = devm_ioremap_resource(dev, res);
        if (IS_ERR(vop->regs))
                return PTR_ERR(vop->regs);
+       vop->len = resource_size(res);
 
        vop->regsbak = devm_kzalloc(dev, vop->len, GFP_KERNEL);
        if (!vop->regsbak)