Re: [PATCH 15/16] net: phy: adin: add ethtool get_stats support

Andrew Lunn
2019-08-05T15:28:37Z

> +struct adin_hw_stat {
> + const char *string;

> +static void adin_get_strings(struct phy_device *phydev, u8 *data)
> +{
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(adin_hw_stats); i++) {
> + memcpy(data + i * ETH_GSTRING_LEN,
> + adin_hw_stats[i].string, ETH_GSTRING_LEN);

You define string as a char *. So it will be only as long as it should
be. However memcpy always copies ETH_GSTRING_LEN bytes, doing off the
end of the string and into whatever follows.

> + }
> +}
> +
> +static int adin_read_mmd_stat_regs(struct phy_device *phydev,
> + struct adin_hw_stat *stat,
> + u32 *val)
> +{
> + int ret;
> +
> + ret = phy_read_mmd(phydev, MDIO_MMD_VEND1, stat->reg1);
> + if (ret < 0)
> + return ret;
> +
> + *val = (ret & 0xffff);
> +
> + if (stat->reg2 == 0)
> + return 0;
> +
> + ret = phy_read_mmd(phydev, MDIO_MMD_VEND1, stat->reg2);
> + if (ret < 0)
> + return ret;
> +
> + *val <<= 16;
> + *val |= (ret & 0xffff);

Does the hardware have a snapshot feature? Is there a danger that
between the two reads stat->reg1 rolls over and you end up with too
big a value?

Andrew