Commit aa6b1956 authored Jul 31, 2019 by Heiner Kallweit Committed by David S. Miller Aug 02, 2019

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: liuyonglong <liuyonglong@huawei.com>
Tested-by: liuyonglong <liuyonglong@huawei.com>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 2802d2cf

drivers/net/phy/phy_device.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -1774,6 +1774,12 @@ done:
		phydev->link = status & BMSR_LSTATUS ? 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;
		}
		EXPORT_SYMBOL(genphy_update_link);

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