The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From af1a02aa23c37045e6adfcf074cf7dbac167a403 Mon Sep 17 00:00:00 2001

From: Andrew Lunn andrew@lunn.ch Date: Sun, 24 Oct 2021 21:48:05 +0200 Subject: [PATCH] phy: phy_ethtool_ksettings_set: Lock the PHY while changing settings

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

diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c index d845afab1af7..a3bfb156c83d 100644 --- a/drivers/net/phy/phy.c +++ b/drivers/net/phy/phy.c @@ -798,6 +798,7 @@ int phy_ethtool_ksettings_set(struct phy_device *phydev, duplex != DUPLEX_FULL))) return -EINVAL;

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

if (autoneg == AUTONEG_DISABLE) { @@ -814,8 +815,9 @@ int phy_ethtool_ksettings_set(struct phy_device *phydev, 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);