This is a note to let you know that I've just added the patch titled net: phy: Check for read errors in SIOCGMIIREG to the 6.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-phy-check-for-read-errors-in-siocgmiireg.patch and it can be found in the queue-6.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 6d3f7646fb0c6b67b8d1ebe7121b6076786b4fa7 Author: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx> Date: Tue Sep 3 19:15:36 2024 +0200 net: phy: Check for read errors in SIOCGMIIREG [ Upstream commit 569bf6d481b0b823c3c9c3b8be77908fd7caf66b ] When reading registers from the PHY using the SIOCGMIIREG IOCTL any errors returned from either mdiobus_read() or mdiobus_c45_read() are ignored, and parts of the returned error is passed as the register value back to user-space. For example, if mdiobus_c45_read() is used with a bus that do not implement the read_c45() callback -EOPNOTSUPP is returned. This is however directly stored in mii_data->val_out and returned as the registers content. As val_out is a u16 the error code is truncated and returned as a plausible register value. Fix this by first checking the return value for errors before returning it as the register content. Before this patch, # phytool read eth0/0:1/0 0xffa1 After this change, $ phytool read eth0/0:1/0 error: phy_read (-95) Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx> Reviewed-by: Florian Fainelli <florian.fainelli@xxxxxxxxxxxx> Reviewed-by: Andrew Lunn <andrew@xxxxxxx> Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx> Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx> Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> Link: https://patch.msgid.link/20240903171536.628930-1-niklas.soderlund+renesas@xxxxxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c index c4236564c1cd0..8495b111a524a 100644 --- a/drivers/net/phy/phy.c +++ b/drivers/net/phy/phy.c @@ -342,14 +342,19 @@ int phy_mii_ioctl(struct phy_device *phydev, struct ifreq *ifr, int cmd) if (mdio_phy_id_is_c45(mii_data->phy_id)) { prtad = mdio_phy_id_prtad(mii_data->phy_id); devad = mdio_phy_id_devad(mii_data->phy_id); - mii_data->val_out = mdiobus_c45_read( - phydev->mdio.bus, prtad, devad, - mii_data->reg_num); + ret = mdiobus_c45_read(phydev->mdio.bus, prtad, devad, + mii_data->reg_num); + } else { - mii_data->val_out = mdiobus_read( - phydev->mdio.bus, mii_data->phy_id, - mii_data->reg_num); + ret = mdiobus_read(phydev->mdio.bus, mii_data->phy_id, + mii_data->reg_num); } + + if (ret < 0) + return ret; + + mii_data->val_out = ret; + return 0; case SIOCSMIIREG: