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authorHeiner Kallweit <hkallweit1@gmail.com>2019-02-13 20:12:54 +0100
committerDavid S. Miller <davem@davemloft.net>2019-02-14 12:04:55 -0500
commita20049071796691cf99eb6433968fc3c27632b95 (patch)
tree5c4576e502af6717242dee142475bf318856d0cc
parenta2fc9d7e36f6d484d9be4a0a204400aaf6059544 (diff)
net: phy: fix potential race in the phylib state machine
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> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/phy/phy.c2
1 files changed, 2 insertions, 0 deletions
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);
}
/**