From: Russell King <rmk+kernel@arm.linux.org.uk>
To: Florian Fainelli <f.fainelli@gmail.com>,
David Miller <davem@davemloft.net>
Cc: devicetree@vger.kernel.org, Frank Rowand <frowand.list@gmail.com>,
Grant Likely <grant.likely@linaro.org>,
Iyappan Subramanian <isubramanian@apm.com>,
Keyur Chudgar <kchudgar@apm.com>,
linux-arm-kernel@lists.infradead.org,
linuxppc-dev@lists.ozlabs.org, Li Yang <leoli@freescale.com>,
Michal Simek <michal.simek@xilinx.com>,
netdev@vger.kernel.org, Robert Richter <rric@kernel.org>,
Rob Herring <robh+dt@kernel.org>,
"Soren Brinkmann" <soren.brinkmann@xilinx.com>,
Sunil Goutham <sgoutham@cavium.com>,
Thomas Petazzoni <thomas.petazzoni@free-electrons.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH RESEND v3 4/9] phy: add proper phy struct device refcounting
Date: Thu, 24 Sep 2015 20:36:08 +0100 [thread overview]
Message-ID: <E1ZfCJM-0004Re-2O@rmk-PC.arm.linux.org.uk> (raw)
In-Reply-To: <20150922161710.GA21084@n2100.arm.linux.org.uk>
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>
---
drivers/net/phy/phy_device.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
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);
--
2.1.0
next prev parent reply other threads:[~2015-09-24 19:36 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-22 16:17 [PATCH v2 0/9] Phy, mdiobus, and netdev struct device fixes Russell King - ARM Linux
2015-09-22 16:18 ` [PATCH 1/9] phy: fix of_mdio_find_bus() device refcount leak Russell King
2015-09-22 16:18 ` [PATCH 2/9] net: dsa: " Russell King
2015-09-22 16:18 ` [PATCH 3/9] phy: fix mdiobus module safety Russell King
2015-09-22 16:18 ` [PATCH 4/9] phy: add proper phy struct device refcounting Russell King
2015-09-22 16:18 ` [PATCH 5/9] of_mdio: fix MDIO phy " Russell King
2015-09-22 16:18 ` [PATCH 6/9] net: fix phy refcounting in a bunch of drivers Russell King
2015-09-22 16:18 ` [PATCH 7/9] phy: fixed-phy: properly validate phy in fixed_phy_update_state() Russell King
2015-09-22 16:18 ` [PATCH 8/9] phy: add phy_device_remove() Russell King
2015-09-22 16:18 ` [PATCH 9/9] net: fix net_device refcounting Russell King
2015-09-23 23:24 ` [PATCH v2 0/9] Phy, mdiobus, and netdev struct device fixes David Miller
2015-09-24 16:00 ` Russell King - ARM Linux
2015-09-24 19:35 ` [PATCH RESEND v3 1/9] phy: fix of_mdio_find_bus() device refcount leak Russell King
2015-09-24 19:35 ` [PATCH RESEND v3 2/9] net: dsa: " Russell King
2015-09-24 19:36 ` [PATCH RESEND v3 3/9] phy: fix mdiobus module safety Russell King
2015-09-24 19:36 ` Russell King [this message]
2015-09-24 19:36 ` [PATCH RESEND v3 5/9] of_mdio: fix MDIO phy device refcounting Russell King
2015-09-24 22:21 ` Rob Herring
2015-09-24 19:36 ` [PATCH RESEND v3 6/9] net: fix phy refcounting in a bunch of drivers Russell King
2015-09-24 19:36 ` [PATCH RESEND v3 7/9] phy: fixed-phy: properly validate phy in fixed_phy_update_state() Russell King
2015-09-24 19:36 ` [PATCH RESEND v3 8/9] phy: add phy_device_remove() Russell King
2015-09-24 19:36 ` [PATCH RESEND v3 9/9] net: fix net_device refcounting Russell King
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