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);
This pattern of:
platform_get_resource_byname
devm_ioremap
is extremely common and could perhaps be factored out. There are
already a few private versions, e.g., request_and_map(),
msm_ioremap(), ssi_get_iomem().
request_and_map() also includes devm_request_mem_region(), which
probably *should* be included but usually seems to be omitted.
> 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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