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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Yang Yingliang <yangyingliang@huawei.com>,
        Heiko Stuebner <heiko@sntech.de>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.18 381/879] drm/rockchip: vop: fix possible null-ptr-deref in vop_bind()
Date:   Tue,  7 Jun 2022 18:58:19 +0200
Message-Id: <20220607165013.927700716@linuxfoundation.org>
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From: Yang Yingliang <yangyingliang@huawei.com>

[ 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>
---
 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 3e8d9e2d1b67..d53037531f40 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
@@ -2118,10 +2118,10 @@ 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);
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
 	if (res) {
-- 
2.35.1