From: Wei Yongjun <weiyongjun1@huawei.com>
Date: Tue, 20 Mar 2018 14:20:30 +0000
Subject: drm/meson: Fix potential NULL dereference in meson_drv_bind_master()
Git-commit: acaa3f13b8dd77da3c6c0fe18cb1159eef7ea286
Patch-mainline: v4.17-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

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

Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/meson/meson_drv.c |    4 ++++
 1 file changed, 4 insertions(+)

--- 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
 	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
 	}
 
 	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) {