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From:   Brandon Maier <brandon.maier@rockwellcollins.com>
To:     netdev@vger.kernel.org
Cc:     andrew@lunn.ch, f.fainelli@gmail.com, davem@davemloft.net,
        michal.simek@xilinx.com, clayton.shotwell@rockwellcollins.com,
        kristopher.cory@rockwellcollins.com, linux-kernel@vger.kernel.org,
        Brandon Maier <brandon.maier@rockwellcollins.com>
Subject: [PATCH 1/3] net: phy: Check phy_driver ready before accessing
Date:   Thu,  7 Jun 2018 10:53:46 -0500
Message-Id: <20180607155348.149665-1-brandon.maier@rockwellcollins.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Since a phy_device is added to the global mdio_bus list during
phy_device_register(), but a phy_device's phy_driver doesn't get
attached until phy_probe(). It's possible of_phy_find_device() in
xgmiitorgmii will return a valid phy with a NULL phy_driver. Leading to
a NULL pointer access during the memcpy().

Signed-off-by: Brandon Maier <brandon.maier@rockwellcollins.com>
---
 drivers/net/phy/xilinx_gmii2rgmii.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/phy/xilinx_gmii2rgmii.c b/drivers/net/phy/xilinx_gmii2rgmii.c
index 2e5150b0b8d5..04c8bec1c4c1 100644
--- a/drivers/net/phy/xilinx_gmii2rgmii.c
+++ b/drivers/net/phy/xilinx_gmii2rgmii.c
@@ -81,6 +81,11 @@ static int xgmiitorgmii_probe(struct mdio_device *mdiodev)
 		return -EPROBE_DEFER;
 	}
 
+	if (!priv->phy_dev->drv) {
+		dev_info(dev, "Attached phy not ready\n");
+		return -EPROBE_DEFER;
+	}
+
 	priv->addr = mdiodev->addr;
 	priv->phy_drv = priv->phy_dev->drv;
 	memcpy(&priv->conv_phy_drv, priv->phy_dev->drv,
-- 
2.14.3