On Thu, 25 Jul 2024 10:29:42 +0800, Ma Ke wrote:
> It could lead to error happen because the variable res is not updated if
> the call to sr_share_read_word returns an error. In this particular case
> error code was returned and res stayed uninitialized. Same issue also
> applies to sr_read_reg.
>
> This can be avoided by checking the return value of sr_share_read_word
> and sr_read_reg, and propagating the error if the read operation failed.
>
> Found by code review.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: c9b37458e956 ("USB2NET : SR9700 : One chip USB 1.1 USB2NET SR9700Device Driver Support")
> Signed-off-by: Ma Ke <make24@xxxxxxxxxxx>
I did a quick check for sr9700.c and there seems to be other
suspicious usage of sr_read_reg(). But, for sr_mdio_read(), I think
the patch is sufficient.
Reviewed-by: Shigeru Yoshida <syoshida@xxxxxxxxxx>
> ---
> Changes in v4:
> - added a check for sr_read_reg() as suggestions.
> Changes in v3:
> - added Cc stable line as suggestions.
> Changes in v2:
> - modified the subject as suggestions.
> ---
> drivers/net/usb/sr9700.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/usb/sr9700.c b/drivers/net/usb/sr9700.c
> index 0a662e42ed96..cb7d2f798fb4 100644
> --- a/drivers/net/usb/sr9700.c
> +++ b/drivers/net/usb/sr9700.c
> @@ -179,6 +179,7 @@ static int sr_mdio_read(struct net_device *netdev, int phy_id, int loc)
> struct usbnet *dev = netdev_priv(netdev);
> __le16 res;
> int rc = 0;
> + int err;
>
> if (phy_id) {
> netdev_dbg(netdev, "Only internal phy supported\n");
> @@ -189,11 +190,17 @@ static int sr_mdio_read(struct net_device *netdev, int phy_id, int loc)
> if (loc == MII_BMSR) {
> u8 value;
>
> - sr_read_reg(dev, SR_NSR, &value);
> + err = sr_read_reg(dev, SR_NSR, &value);
> + if (err < 0)
> + return err;
> +
> if (value & NSR_LINKST)
> rc = 1;
> }
> - sr_share_read_word(dev, 1, loc, &res);
> + err = sr_share_read_word(dev, 1, loc, &res);
> + if (err < 0)
> + return err;
> +
> if (rc == 1)
> res = le16_to_cpu(res) | BMSR_LSTATUS;
> else
> --
> 2.25.1
>
