linux-kernel - [PATCH 4.19 052/120] PCI: mediatek: Add missing of_node

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Message-Id: <20210315135721.694658178@linuxfoundation.org>
Date:   Mon, 15 Mar 2021 14:56:43 +0100
From:   gregkh@...uxfoundation.org
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Krzysztof Wilczyński <kw@...ux.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 052/120] PCI: mediatek: Add missing of_node_put() to fix reference leak

From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

From: Krzysztof Wilczyński <kw@...ux.com>

[ Upstream commit 42814c438aac79746d310f413a27d5b0b959c5de ]

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.

Link: https://lore.kernel.org/r/20210120184810.3068794-1-kw@linux.com
Signed-off-by: Krzysztof Wilczyński <kw@...ux.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 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 ca06d8bc01e7..066e9e00de11 100644
--- a/drivers/pci/controller/pcie-mediatek.c
+++ b/drivers/pci/controller/pcie-mediatek.c
@@ -1089,14 +1089,14 @@ 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);
@@ -1112,6 +1112,9 @@ 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_request_resources(struct mtk_pcie *pcie)
-- 
2.30.1