[PATCH] PCI: mediatek: Add missing of_node_put() to fix reference leak

[PATCH] PCI: mediatek: Add missing of_node_put() to fix reference leak

[Krzysztof Wilczyński]

The for_each_available_child_of_node helper internally makes use of the
of_get_next_available_child() which performs an of_node_get() on each
iteration when searching for next available child node.

Should an available child node be found, then it would return a device
node pointer with reference count incremented, thus early return from
the middle of the loop requires an explicit of_node_put() to prevent
reference count leak.

To stop the reference leak, explicitly call of_node_put() before
returning after an error occurred.

Signed-off-by: Krzysztof Wilczyński <kw@linux.com>
---
 drivers/pci/controller/pcie-mediatek.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c
index cf4c18f0c25a..23548b517e4b 100644
--- a/drivers/pci/controller/pcie-mediatek.c
+++ b/drivers/pci/controller/pcie-mediatek.c
@@ -1035,14 +1035,14 @@ static int mtk_pcie_setup(struct mtk_pcie *pcie)
 		err = of_pci_get_devfn(child);
 		if (err < 0) {
 			dev_err(dev, "failed to parse devfn: %d\n", err);
-			return err;
+			goto error_put_node;
 		}
 
 		slot = PCI_SLOT(err);
 
 		err = mtk_pcie_parse_port(pcie, child, slot);
 		if (err)
-			return err;
+			goto error_put_node;
 	}
 
 	err = mtk_pcie_subsys_powerup(pcie);
@@ -1058,6 +1058,9 @@ static int mtk_pcie_setup(struct mtk_pcie *pcie)
 		mtk_pcie_subsys_powerdown(pcie);
 
 	return 0;
+error_put_node:
+	of_node_put(child);
+	return err;
 }
 
 static int mtk_pcie_probe(struct platform_device *pdev)
-- 
2.30.0

Re: [PATCH] PCI: mediatek: Add missing of_node_put() to fix reference leak

[Lorenzo Pieralisi]

On Wed, 20 Jan 2021 18:48:10 +0000, Krzysztof Wilczyński wrote:
> The for_each_available_child_of_node helper internally makes use of the
> of_get_next_available_child() which performs an of_node_get() on each
> iteration when searching for next available child node.
> 
> Should an available child node be found, then it would return a device
> node pointer with reference count incremented, thus early return from
> the middle of the loop requires an explicit of_node_put() to prevent
> reference count leak.
> 
> [...]

Applied to pci/mediatek, thanks!

[1/1] PCI: mediatek: Add missing of_node_put() to fix reference leak
      https://git.kernel.org/lpieralisi/pci/c/42814c438a

Thanks,
Lorenzo