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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, Wei Yongjun <weiyongjun1@huawei.com>,
        Grygorii Strashko <grygorii.strashko@ti.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.7 145/376] drivers: net: davinci_mdio: fix potential NULL dereference in davinci_mdio_probe()
Date:   Fri, 19 Jun 2020 16:31:03 +0200
Message-Id: <20200619141717.196501012@linuxfoundation.org>
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From: Wei Yongjun <weiyongjun1@huawei.com>

[ Upstream commit e00edb4efbbc07425441a3be2aa87abaf5800d96 ]

platform_get_resource() may fail and return NULL, so we should
better check it's return value to avoid a NULL pointer dereference
since devm_ioremap() does not check input parameters for null.

This is detected by Coccinelle semantic patch.

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

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

Fixes: 03f66f067560 ("net: ethernet: ti: davinci_mdio: use devm_ioremap()")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/ti/davinci_mdio.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/ti/davinci_mdio.c b/drivers/net/ethernet/ti/davinci_mdio.c
index 38b7f6d35759..702fdc393da0 100644
--- a/drivers/net/ethernet/ti/davinci_mdio.c
+++ b/drivers/net/ethernet/ti/davinci_mdio.c
@@ -397,6 +397,8 @@ static int davinci_mdio_probe(struct platform_device *pdev)
 	data->dev = dev;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -EINVAL;
 	data->regs = devm_ioremap(dev, res->start, resource_size(res));
 	if (!data->regs)
 		return -ENOMEM;
-- 
2.25.1