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From:   Michael Walle <michael@walle.cc>
To:     Horatiu Vultur <horatiu.vultur@microchip.com>,
        "David S . Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>
Cc:     UNGLinuxDriver@microchip.com, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, Michael Walle <michael@walle.cc>
Subject: [PATCH v2 net] net: lan966x: fix kernel oops on ioctl when I/F is down
Date:   Tue, 29 Mar 2022 00:03:50 +0200
Message-Id: <20220328220350.3118969-1-michael@walle.cc>
MIME-Version: 1.0
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ioctls handled by phy_mii_ioctl() will cause a kernel oops when the
interface is down. Fix it by making sure there is a PHY attached.

Fixes: 735fec995b21 ("net: lan966x: Implement SIOCSHWTSTAMP and SIOCGHWTSTAMP")
Signed-off-by: Michael Walle <michael@walle.cc>
---
changes since v1:
 - reword commit message
 - test for the presence of phydev instead of the interface state
 - move the test just before phy_mii_ioctl()

 drivers/net/ethernet/microchip/lan966x/lan966x_main.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_main.c b/drivers/net/ethernet/microchip/lan966x/lan966x_main.c
index ec42e526f6fb..1759b0e2b56f 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_main.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_main.c
@@ -408,6 +408,9 @@ static int lan966x_port_ioctl(struct net_device *dev, struct ifreq *ifr,
 		}
 	}
 
+	if (!dev->phydev)
+		return -ENODEV;
+
 	return phy_mii_ioctl(dev->phydev, ifr, cmd);
 }
 
-- 
2.30.2