Re: [PATCH -next] PCI: dwc: pci-dra7xx: Fix potential NULL dereference in dra7xx_pcie_probe()

From: Dan Carpenter <dan.carpenter@oracle.com>
To: Vignesh Raghavendra <vigneshr@ti.com>
Cc: Wei Yongjun <weiyongjun1@huawei.com>,
	Kishon Vijay Abraham I <kishon@ti.com>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Rob Herring <robh@kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	linux-omap@vger.kernel.org, linux-pci@vger.kernel.org,
	kernel-janitors@vger.kernel.org
Subject: Re: [PATCH -next] PCI: dwc: pci-dra7xx: Fix potential NULL dereference in dra7xx_pcie_probe()
Date: Tue, 28 Apr 2020 13:07:34 +0000	[thread overview]
Message-ID: <20200428130734.GF2014@kadam> (raw)
In-Reply-To: <cad871c8-0915-9dda-2c61-30dfb5504d23@ti.com>

On Mon, Apr 27, 2020 at 05:29:50PM +0530, Vignesh Raghavendra wrote:
> Hi,
> 
> On 27/04/20 4:40 pm, 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>
> > ---
> >  drivers/pci/controller/dwc/pci-dra7xx.c | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/drivers/pci/controller/dwc/pci-dra7xx.c b/drivers/pci/controller/dwc/pci-dra7xx.c
> > index 3b0e58f2de58..7a3d12f7e7d9 100644
> > --- a/drivers/pci/controller/dwc/pci-dra7xx.c
> > +++ b/drivers/pci/controller/dwc/pci-dra7xx.c
> > @@ -878,6 +878,9 @@ static int __init dra7xx_pcie_probe(struct platform_device *pdev)
> >  	}
> >  
> >  	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "ti_conf");
                                           ^^^^

> > +	if (!res)
> > +		return -EINVAL;
> > +
> >  	base = devm_ioremap(dev, res->start, resource_size(res));
                            ^^^
> 
> I don't see why this should be devm_ioremap(). It should also have been
> devm_ioremap_resource() which does the NULL check.

It's different device pointers.

regards,
dan carpenter