On Thu, Jan 18, 2018 at 03:54:20PM +0100, Ladislav Michl wrote:
> On Thu, Jan 18, 2018 at 02:00:37PM +0000, Wei Yongjun wrote:
> > 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);
>
> Well, then it should be replaced with devm_ioremap_resource()
> which already checks for NULL and the right resource type
> (IORESOURCE_MEM).
That's probably a better idea. Maybe we should add a comment like this
to help avoid this in the future:
--- a/lib/devres.c
+++ b/lib/devres.c
@@ -22,6 +22,8 @@ static int devm_ioremap_match(struct device *dev, void *res, void *match_data)
* @size: Size of map
*
* Managed ioremap(). Map is automatically unmapped on driver detach.
+ *
+ * When possible, use devm_ioremap_resource() instead.
*/
void __iomem *devm_ioremap(struct device *dev, resource_size_t offset,
resource_size_t size)
> > Fixes: 608793e27b33 ("PCI: dwc: dra7xx: Add EP mode support")
> > Signed-off-by: Wei Yongjun <weiyongjun1@xxxxxxxxxx>
> > ---
> > drivers/pci/dwc/pci-dra7xx.c | 6 ++++++
> > 1 file changed, 6 insertions(+)
> >
> > diff --git a/drivers/pci/dwc/pci-dra7xx.c b/drivers/pci/dwc/pci-dra7xx.c
> > index 8bf7c27..aafded8 100644
> > --- a/drivers/pci/dwc/pci-dra7xx.c
> > +++ b/drivers/pci/dwc/pci-dra7xx.c
> > @@ -409,11 +409,15 @@ static int __init dra7xx_add_pcie_ep(struct dra7xx_pcie *dra7xx,
> > ep->ops = &pcie_ep_ops;
> >
> > res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "ep_dbics");
> > + if (!res)
> > + return -EINVAL;
> > pci->dbi_base = devm_ioremap(dev, res->start, resource_size(res));
> > if (!pci->dbi_base)
> > return -ENOMEM;
> >
> > res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "ep_dbics2");
> > + if (!res)
> > + return -EINVAL;
> > pci->dbi_base2 = devm_ioremap(dev, res->start, resource_size(res));
> > if (!pci->dbi_base2)
> > return -ENOMEM;
> > @@ -462,6 +466,8 @@ static int __init dra7xx_add_pcie_port(struct dra7xx_pcie *dra7xx,
> > return ret;
> >
> > res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rc_dbics");
> > + if (!res)
> > + return -EINVAL;
> > pci->dbi_base = devm_ioremap(dev, res->start, resource_size(res));
> > if (!pci->dbi_base)
> > return -ENOMEM;
> >
> > --
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