[PATCH 4.19 084/287] drm/rockchip: vop: fix possible null-ptr-deref in vop_bind()

[Greg Kroah-Hartman]

From: Yang Yingliang <yangyingliang@xxxxxxxxxx>

[ 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@xxxxxxxxxx>
Signed-off-by: Heiko Stuebner <heiko@xxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20220422032854.2995175-1-yangyingliang@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
index 873624a11ce8..c0b647435974 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
@@ -1595,10 +1595,10 @@ 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)
-- 
2.35.1