drm/meson: Fix potential NULL dereference in meson_drv_bind_master()

platform_get_resource_byname() may fail and return NULL, so we should
better check it's return value to avoid a NULL pointer dereference
a bit later in the code.

This is detected by Coccinelle semantic patch.

@@
expression pdev, res, n, t, e, e1, e2;
@@

res = platform_get_resource_byname(pdev, t, n);
+ if (!res)
+   return -EINVAL;
... when != res == NULL
e = devm_ioremap(e1, res->start, e2);

Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1521555630-29284-1-git-send-email-weiyongjun1@huawei.com

diff --git a/drivers/gpu/drm/meson/meson_drv.c b/drivers/gpu/drm/meson/meson_drv.c
index 3baceb7..32b1a6c 100644 (file)
--- a/drivers/gpu/drm/meson/meson_drv.c
+++ b/drivers/gpu/drm/meson/meson_drv.c
@@ -197,6 +197,8 @@ static int meson_drv_bind_master(struct device *dev, bool has_components)
        priv->io_base = regs;
 
        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "hhi");
+       if (!res)
+               return -EINVAL;
        /* Simply ioremap since it may be a shared register zone */
        regs = devm_ioremap(dev, res->start, resource_size(res));
        if (!regs) {
@@ -213,6 +215,8 @@ static int meson_drv_bind_master(struct device *dev, bool has_components)
        }
 
        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dmc");
+       if (!res)
+               return -EINVAL;
        /* Simply ioremap since it may be a shared register zone */
        regs = devm_ioremap(dev, res->start, resource_size(res));
        if (!regs) {