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| author | Russell King <rmk+kernel@arm.linux.org.uk> | 2015-09-24 20:36:08 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-09-24 23:04:52 -0700 |
| commit | 7322967bc1bd97ac9c49ecea19e5a1f681ca27ee (patch) | |
| tree | 8dbce2e4e1eb98757ef30b537977d447999b1582 | |
| parent | 3e3aaf649416988ca8be4ad2c52dc24d8be7b46e (diff) | |
| download | linux-7322967bc1bd97ac9c49ecea19e5a1f681ca27ee.tar.bz2 | |
phy: add proper phy struct device refcounting
Take a refcount on the phy struct device when the phy device is attached
to a network device, and drop it after it's detached. This ensures that
a refcount is held on the phy device while the device is being used by
a network device, thereby preventing the phy_device from being
unexpectedly kfree()'d by phy_device_release().
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | drivers/net/phy/phy_device.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c index 03adf328f49b..97a4f52addac 100644 --- a/drivers/net/phy/phy_device.c +++ b/drivers/net/phy/phy_device.c @@ -578,6 +578,7 @@ EXPORT_SYMBOL(phy_init_hw); * generic driver is used. The phy_device is given a ptr to * the attaching device, and given a callback for link status * change. The phy_device is returned to the attaching driver. + * This function takes a reference on the phy device. */ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev, u32 flags, phy_interface_t interface) @@ -591,6 +592,8 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev, return -EIO; } + get_device(d); + /* Assume that if there is no driver, that it doesn't * exist, and we should use the genphy driver. */ @@ -636,6 +639,7 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev, return err; error: + put_device(d); module_put(bus->owner); return err; } @@ -679,6 +683,9 @@ EXPORT_SYMBOL(phy_attach); /** * phy_detach - detach a PHY device from its network device * @phydev: target phy_device struct + * + * This detaches the phy device from its network device and the phy + * driver, and drops the reference count taken in phy_attach_direct(). */ void phy_detach(struct phy_device *phydev) { @@ -701,8 +708,13 @@ void phy_detach(struct phy_device *phydev) } } + /* + * The phydev might go away on the put_device() below, so avoid + * a use-after-free bug by reading the underlying bus first. + */ bus = phydev->bus; + put_device(&phydev->dev); module_put(bus->owner); } EXPORT_SYMBOL(phy_detach); |