[PATCH 5.10 64/77] phy: phy_ethtool_ksettings_set: Lock the PHY while changing settings

Greg Kroah-Hartman
2021-11-01T09:38:29Z

From: Andrew Lunn <andrew@lunn.ch>

commit af1a02aa23c37045e6adfcf074cf7dbac167a403 upstream.

There is a race condition where the PHY state machine can change
members of the phydev structure at the same time userspace requests a
change via ethtool. To prevent this, have phy_ethtool_ksettings_set
take the PHY lock.

Fixes: 2d55173e71b0 ("phy: add generic function to support ksetting support")
Reported-by: Walter Stoll <Walter.Stoll@duagon.com>
Suggested-by: Walter Stoll <Walter.Stoll@duagon.com>
Tested-by: Walter Stoll <Walter.Stoll@duagon.com>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/phy/phy.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -814,6 +814,7 @@ int phy_ethtool_ksettings_set(struct phy
duplex != DUPLEX_FULL)))
return -EINVAL;

+ mutex_lock(&phydev->lock);
phydev->autoneg = autoneg;

if (autoneg == AUTONEG_DISABLE) {
@@ -830,8 +831,9 @@ int phy_ethtool_ksettings_set(struct phy
phydev->mdix_ctrl = cmd->base.eth_tp_mdix_ctrl;

/* Restart the PHY */
- phy_start_aneg(phydev);
+ _phy_start_aneg(phydev);

+ mutex_unlock(&phydev->lock);
return 0;
}
EXPORT_SYMBOL(phy_ethtool_ksettings_set);