Messages in this thread | | | Subject | Re: [PATCH net v2] net: mdio-ipq4019: fix possible invalid pointer dereference | From | Hui Tang <> | Date | Fri, 18 Nov 2022 15:21:24 +0800 |
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On 2022/11/17 21:57, Andrew Lunn wrote: > On Thu, Nov 17, 2022 at 05:05:14PM +0800, Hui Tang wrote: >> priv->eth_ldo_rdy is saved the return value of devm_ioremap_resource(), >> which !IS_ERR() should be used to check. >> >> Fixes: 23a890d493e3 ("net: mdio: Add the reset function for IPQ MDIO driver") >> Signed-off-by: Hui Tang <tanghui20@huawei.com> >> --- >> v1 -> v2: set priv->eth_ldo_rdy NULL, if devm_ioremap_resource() failed >> --- >> drivers/net/mdio/mdio-ipq4019.c | 5 ++++- >> 1 file changed, 4 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/net/mdio/mdio-ipq4019.c b/drivers/net/mdio/mdio-ipq4019.c >> index 4eba5a91075c..dfd1647eac36 100644 >> --- a/drivers/net/mdio/mdio-ipq4019.c >> +++ b/drivers/net/mdio/mdio-ipq4019.c >> @@ -231,8 +231,11 @@ static int ipq4019_mdio_probe(struct platform_device *pdev) >> /* The platform resource is provided on the chipset IPQ5018 */ >> /* This resource is optional */ >> res = platform_get_resource(pdev, IORESOURCE_MEM, 1); >> - if (res) >> + if (res) { >> priv->eth_ldo_rdy = devm_ioremap_resource(&pdev->dev, res); >> + if (IS_ERR(priv->eth_ldo_rdy)) >> + priv->eth_ldo_rdy = NULL; >> + } > > As i said, please add devm_ioremap_resource_optional(). Follow the > concept of devm_clk_get_optional(), devm_gpiod_get_optional(), > devm_reset_control_get_optional(), devm_reset_control_get_optional(), > platform_get_irq_byname_optional() etc. > > All these will not return an error if the resource you are trying to > get does not exist. They instead return NULL, or something which other > API members understand as does not exist, but thats O.K. > > These functions however do return errors for real problem, ENOMEM, > EINVAL etc. These should not be ignored. > > You should then use this new function for all your other patches where > the resource is optional.
I finally understand what you mean now.
I need add devm_ioremap_resource_optional() helper, which return NULL if the resource does not exist, and if it return other errors we need to deal with errors. In my case, it returns -ENOMEM if the resource does not exist.
So, the code should be as follows, is that right?
+ void __iomem *devm_ioremap_resource_optional(struct device *dev, + const struct resource *res) + { + void __iomem *base; + + base = __devm_ioremap_resource(dev, res, DEVM_IOREMAP); + if (IS_ERR(base) && PTR_ERR(base) == -ENOMEM) + return NULL; + + return base; + }
[...] res = platform_get_resource(pdev, IORESOURCE_MEM, 1); - if (res) + if (res) { + priv->eth_ldo_rdy = devm_ioremap_resource_optional(&pdev->dev, res) + if (IS_ERR(priv->eth_ldo_rdy)) + return PTR_ERR(priv->eth_ldo_rdy); + } [...]
thanks.
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