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From:   Siddharth Vadapalli <s-vadapalli@ti.com>
To:     <davem@davemloft.net>, <edumazet@google.com>, <kuba@kernel.org>,
        <pabeni@redhat.com>, <rogerq@kernel.org>
CC:     <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>, <srk@ti.com>,
        <s-vadapalli@ti.com>
Subject: [PATCH net] net: ethernet: ti: am65-cpsw: Fix mdio cleanup in probe
Date:   Mon, 3 Apr 2023 14:33:21 +0530
Message-ID: <20230403090321.835877-1-s-vadapalli@ti.com>
MIME-Version: 1.0
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Precedence: bulk

In the am65_cpsw_nuss_probe() function's cleanup path, the call to
of_platform_device_destroy() for the common->mdio_dev device is invoked
unconditionally. It is possible that either the MDIO node is not present
in the device-tree, or the MDIO node is disabled in the device-tree. In
both these cases, the MDIO device is not created, resulting in a NULL
pointer dereference when the of_platform_device_destroy() function is
invoked on the common->mdio_dev device on the cleanup path.

Fix this by ensuring that the common->mdio_dev device exists, before
attempting to invoke of_platform_device_destroy().

Fixes: a45cfcc69a25 ("net: ethernet: ti: am65-cpsw-nuss: use of_platform_device_create() for mdio")
Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
---
 drivers/net/ethernet/ti/am65-cpsw-nuss.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
index 4e3861c47708..bcea87b7151c 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
@@ -2926,7 +2926,8 @@ static int am65_cpsw_nuss_probe(struct platform_device *pdev)
 	am65_cpsw_nuss_phylink_cleanup(common);
 	am65_cpts_release(common->cpts);
 err_of_clear:
-	of_platform_device_destroy(common->mdio_dev, NULL);
+	if (common->mdio_dev)
+		of_platform_device_destroy(common->mdio_dev, NULL);
 err_pm_clear:
 	pm_runtime_put_sync(dev);
 	pm_runtime_disable(dev);
@@ -2956,7 +2957,8 @@ static int am65_cpsw_nuss_remove(struct platform_device *pdev)
 	am65_cpts_release(common->cpts);
 	am65_cpsw_disable_serdes_phy(common);
 
-	of_platform_device_destroy(common->mdio_dev, NULL);
+	if (common->mdio_dev)
+		of_platform_device_destroy(common->mdio_dev, NULL);
 
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
-- 
2.25.1