Messages in this thread | | | Subject | Re: [PATCH] net: mdio-ipq4019: fix possible invalid pointer dereference | From | Hui Tang <> | Date | Thu, 17 Nov 2022 16:50:46 +0800 |
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On 2022/11/15 21:36, Andrew Lunn wrote: > On Tue, Nov 15, 2022 at 12:50:28PM +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> >> --- >> drivers/net/mdio/mdio-ipq4019.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/net/mdio/mdio-ipq4019.c b/drivers/net/mdio/mdio-ipq4019.c >> index 4eba5a91075c..d7a1f7c56f97 100644 >> --- a/drivers/net/mdio/mdio-ipq4019.c >> +++ b/drivers/net/mdio/mdio-ipq4019.c >> @@ -188,7 +188,7 @@ static int ipq_mdio_reset(struct mii_bus *bus) >> /* To indicate CMN_PLL that ethernet_ldo has been ready if platform resource 1 >> * is specified in the device tree. >> */ >> - if (priv->eth_ldo_rdy) { >> + if (!IS_ERR(priv->eth_ldo_rdy)) { >> val = readl(priv->eth_ldo_rdy); >> val |= BIT(0); >> writel(val, priv->eth_ldo_rdy); > > There is a general pattern in the kernel that optional things are set > to NULL if the resource does not exist. Often there is a > get_foo_optional() which will return a NULL point if the things does > not exist, the thing if it does exist, or an error code if a real > error happened. > > So please follow this patterns. Check the return value in > ipq4019_mdio_probe(). Looking at __devm_ioremap_resource() i _think_ > it returns -ENOMEM if the resource does not exist? So maybe any other > error is a real error, and should be reported, and -ENOMEM should > result in eth_ldo_rdy set to NULL?
Thanks, I will resend it according to the style you said.
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