| Message ID | 1094ff3a-0d7a-dc96-8a19-a5102e08fa79@gmail.com |
|---|---|
| State | Accepted |
| Delegated to: | David Miller |
| Headers | show |
| Series | net: phy: fix locking issue | expand |
On 2/13/2019 11:12 AM, Heiner Kallweit wrote: > 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: 2b3e88ea6528 ("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>
diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c index 602816d70281..c5675df5fc6f 100644 --- a/drivers/net/phy/phy.c +++ b/drivers/net/phy/phy.c @@ -985,8 +985,10 @@ void phy_state_machine(struct work_struct *work) * state machine would be pointless and possibly error prone when * called from phy_disconnect() synchronously. */ + mutex_lock(&phydev->lock); if (phy_polling_mode(phydev) && phy_is_started(phydev)) phy_queue_state_machine(phydev, PHY_STATE_TIME); + mutex_unlock(&phydev->lock); } /**
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: 2b3e88ea6528 ("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> --- drivers/net/phy/phy.c | 2 ++ 1 file changed, 2 insertions(+)