net: phy: Avoid NPD upon phy_detach() when driver is unbound

If we have unbound the PHY driver prior to calling phy_detach() (often via phy_disconnect()) then we can cause a NULL pointer de-reference accessing the driver owner member. The steps to reproduce are: echo unimac-mdio-0:01 > /sys/class/net/eth0/phydev/driver/unbind ip link set eth0 down Fixes: cafe8df ("net: phy: Fix lack of reference count on PHY driver") Signed-off-by: Florian Fainelli <[email protected]> Reviewed-by: Andrew Lunn <[email protected]> Signed-off-by: David S. Miller <[email protected]>
zandrey · Sep 17, 2020 · c2b727d · c2b727d
1 parent 19a83d3
commit c2b727d
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
@@ -1682,7 +1682,8 @@ void phy_detach(struct phy_device *phydev)
 
 	phy_led_triggers_unregister(phydev);
 
-	module_put(phydev->mdio.dev.driver->owner);
+	if (phydev->mdio.dev.driver)
+		module_put(phydev->mdio.dev.driver->owner);
 
 	/* If the device had no specific driver before (i.e. - it
 	 * was using the generic driver), we unbind the device