[PATCH 4.19 46/72] net: xilinx: fix possible object reference leak

[ Upstream commit fa3a419d2f674b431d38748cb58fb7da17ee8949 ]

The call to of_parse_phandle returns a node pointer with refcount
incremented thus it must be explicitly decremented after the last
usage.

Detected by coccinelle with the following warnings:
./drivers/net/ethernet/xilinx/xilinx_axienet_main.c:1624:1-7: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 1569, but without a corresponding object release within this function.

Signed-off-by: Wen Yang <redacted>
Cc: Anirudha Sarangi <redacted>
Cc: John Linn <redacted>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Michal Simek <redacted>
Cc: netdev@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin (Microsoft) <sashal@kernel.org>
---
 drivers/net/ethernet/xilinx/xilinx_axienet_main.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index f24f48f33802..7cfd7ff38e86 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c

@@ -1574,12 +1574,14 @@ static int axienet_probe(struct platform_device *pdev)
 	ret = of_address_to_resource(np, 0, &dmares);
 	if (ret) {
 		dev_err(&pdev->dev, "unable to get DMA resource\n");
+		of_node_put(np);
 		goto free_netdev;
 	}
 	lp->dma_regs = devm_ioremap_resource(&pdev->dev, &dmares);
 	if (IS_ERR(lp->dma_regs)) {
 		dev_err(&pdev->dev, "could not map DMA regs\n");
 		ret = PTR_ERR(lp->dma_regs);
+		of_node_put(np);
 		goto free_netdev;
 	}
 	lp->rx_irq = irq_of_parse_and_map(np, 1);

-- 
2.19.1

On Thu 2019-05-02 17:21:08, Greg Kroah-Hartman wrote:

[ Upstream commit fa3a419d2f674b431d38748cb58fb7da17ee8949 ]

The call to of_parse_phandle returns a node pointer with refcount
incremented thus it must be explicitly decremented after the last
usage.

Detected by coccinelle with the following warnings:
./drivers/net/ethernet/xilinx/xilinx_axienet_main.c:1624:1-7: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 1569, but without a corresponding object release within this function.

Signed-off-by: Wen Yang <redacted>
Cc: Anirudha Sarangi <redacted>
Cc: John Linn <redacted>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Michal Simek <redacted>
Cc: netdev@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin (Microsoft) <sashal@kernel.org>

Bug is real, but fix is horrible. This already uses gotos for error
handling, so use them....

This fixes it up.

Plus... I do not think these "of_node_put" fixes belong in
stable. They are theoretical bugs; so we hold reference to device tree
structure. a) it is small, b) it stays in memory, anyway. This does
not fix any real problem.

								Pavel

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index 4041c75..490d440 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c

@@ -1575,15 +1575,13 @@ static int axienet_probe(struct platform_device *pdev)
 	ret = of_address_to_resource(np, 0, &dmares);
 	if (ret) {
 		dev_err(&pdev->dev, "unable to get DMA resource\n");
-		of_node_put(np);
-		goto free_netdev;
+		goto free_netdev_put;
 	}
 	lp->dma_regs = devm_ioremap_resource(&pdev->dev, &dmares);
 	if (IS_ERR(lp->dma_regs)) {
 		dev_err(&pdev->dev, "could not map DMA regs\n");
 		ret = PTR_ERR(lp->dma_regs);
-		of_node_put(np);
-		goto free_netdev;
+		goto free_netdev_put;
 	}
 	lp->rx_irq = irq_of_parse_and_map(np, 1);
 	lp->tx_irq = irq_of_parse_and_map(np, 0);

@@ -1620,6 +1618,8 @@ static int axienet_probe(struct platform_device *pdev)
 
 	return 0;
 
+free_netdev_put:
+	of_node_put(np);
 free_netdev:
 	free_netdev(ndev);
 

-- 
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