re: [PATCH net-next] drivers: net: davinci_mdio: fix potential NULL dereference in davinci_mdio_probe()

From: "weiyongjun (A)" <weiyongjun1@huawei.com>
To: David Lechner <david@lechnology.com>,
	Grygorii Strashko <grygorii.strashko@ti.com>,
	Andrew Lunn <andrew@lunn.ch>
Cc: "linux-omap@vger.kernel.org" <linux-omap@vger.kernel.org>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"kernel-janitors@vger.kernel.org"
	<kernel-janitors@vger.kernel.org>
Subject: re: [PATCH net-next] drivers: net: davinci_mdio: fix potential NULL dereference in davinci_mdio_probe()
Date: Tue, 28 Apr 2020 03:25:09 +0000	[thread overview]
Message-ID: <6AADFAC011213A4C87B956458587ADB419A6B43E@dggeml532-mbs.china.huawei.com> (raw)

> 
> On 4/27/20 4:40 AM, Wei Yongjun wrote:
> > platform_get_resource() 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 = \(platform_get_resource\|platform_get_resource_byname\)(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>
> > ---
> 
> Could we use devm_platform_ioremap_resource() instead?

We cannot use devm_platform_ioremap_resource() here, see
Commit 03f66f067560 ("net: ethernet: ti: davinci_mdio: use devm_ioremap()")

Regards