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

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[ Upstream commit c2b727df7caa33876e7066bde090f40001b6d643 ]

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: cafe8df8b9bc ("net: phy: Fix lack of reference count on PHY driver")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Florian Fainelli 2020-09-16 20:43:09 -07:00 committed by Greg Kroah-Hartman
parent 1f029a2bb4
commit 5427e39992
1 changed files with 2 additions and 1 deletions
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3
drivers/net/phy/phy_device.c
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@ -1013,7 +1013,8 @@ void phy_detach(struct phy_device *phydev)
phydev->attached_dev = NULL;
phy_suspend(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