Commit aa6b1956 authored by Heiner Kallweit's avatar Heiner Kallweit Committed by David S. Miller

net: phy: fix race in genphy_update_link

In phy_start_aneg() autoneg is started, and immediately after that
link and autoneg status are read. As reported in [0] it can happen that
at time of this read the PHY has reset the "aneg complete" bit but not
yet the "link up" bit, what can result in a false link-up detection.
To fix this don't report link as up if we're in aneg mode and PHY
doesn't signal "aneg complete".

[0] https://marc.info/?t=156413509900003&r=1&w=2

Fixes: 4950c2ba ("net: phy: fix autoneg mismatch case in genphy_read_status")
Reported-by: default avatarliuyonglong <liuyonglong@huawei.com>
Tested-by: default avatarliuyonglong <liuyonglong@huawei.com>
Signed-off-by: default avatarHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2802d2cf
...@@ -1774,6 +1774,12 @@ int genphy_update_link(struct phy_device *phydev) ...@@ -1774,6 +1774,12 @@ int genphy_update_link(struct phy_device *phydev)
phydev->link = status & BMSR_LSTATUS ? 1 : 0; phydev->link = status & BMSR_LSTATUS ? 1 : 0;
phydev->autoneg_complete = status & BMSR_ANEGCOMPLETE ? 1 : 0; phydev->autoneg_complete = status & BMSR_ANEGCOMPLETE ? 1 : 0;
/* Consider the case that autoneg was started and "aneg complete"
* bit has been reset, but "link up" bit not yet.
*/
if (phydev->autoneg == AUTONEG_ENABLE && !phydev->autoneg_complete)
phydev->link = 0;
return 0; return 0;
} }
EXPORT_SYMBOL(genphy_update_link); EXPORT_SYMBOL(genphy_update_link);
......
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