From:   Colin Foster <colin.foster@in-advantage.com>
To:     linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Cc:     Florian Fainelli <f.fainelli@gmail.com>,
        Xiaolei Wang <xiaolei.wang@windriver.com>,
        Paolo Abeni <pabeni@redhat.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Eric Dumazet <edumazet@google.com>,
        "David S. Miller" <davem@davemloft.net>,
        Russell King <linux@armlinux.org.uk>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Andrew Lunn <andrew@lunn.ch>
Subject: [PATCH v1 net] net: phy: fix null dereference in phy_attach_direct
Date:   Fri, 27 Jan 2023 09:14:27 -0800
Message-Id: <20230127171427.265023-1-colin.foster@in-advantage.com>
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Commit bc66fa87d4fd ("net: phy: Add link between phy dev and mac dev")
introduced a link between net devices and phy devices. It fails to check
whether dev is NULL, leading to a NULL dereference error.

Fixes: bc66fa87d4fd ("net: phy: Add link between phy dev and mac dev")
Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
---
 drivers/net/phy/phy_device.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 9ba8f973f26f..a3917c7acbd3 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -1538,7 +1538,7 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,
 	 * another mac interface, so we should create a device link between
 	 * phy dev and mac dev.
 	 */
-	if (phydev->mdio.bus->parent && dev->dev.parent != phydev->mdio.bus->parent)
+	if (dev && phydev->mdio.bus->parent && dev->dev.parent != phydev->mdio.bus->parent)
 		phydev->devlink = device_link_add(dev->dev.parent, &phydev->mdio.dev,
 						  DL_FLAG_PM_RUNTIME | DL_FLAG_STATELESS);
 
-- 
2.25.1