Russell reported the following race in the phylib state machine
(quoting from his mail):
if (phy_polling_mode(phydev) && phy_is_started(phydev))
phy_queue_state_machine(phydev, PHY_STATE_TIME);
state = PHY_UP
thread 0 thread 1
phy_disconnect()
+-phy_is_started()
phy_is_started() |
`-phy_stop()
+-phydev->state = PHY_HALTED
`-phy_stop_machine()
`-cancel_delayed_work_sync()
phy_queue_state_machine()
`-mod_delayed_work()
At this point, the phydev->state_queue() has been added back onto the
system workqueue despite phy_stop_machine() having been called and
cancel_delayed_work_sync() called on it.
Fix this by protecting the complete operation in thread 0.
Fixes: 2b3e88ea65 ("net: phy: improve phy state checking")
Reported-by: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
a200490717