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From:   Wen Yang <wen.yang99@zte.com.cn>
To:     benh@kernel.crashing.org
Cc:     paulus@samba.org, mpe@ellerman.id.au, tyreld@linux.vnet.ibm.com,
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        linux-arm-kernel@lists.infradead.org, rjui@broadcom.com,
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        heiko@sntech.de, linux-rockchip@lists.infradead.org,
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        hayashi.kunihiko@socionext.com, yamada.masahiro@socionext.com,
        kishon@ti.com, linux-omap@vger.kernel.org, wang.yi59@zte.com.cn,
        Wen Yang <wen.yang99@zte.com.cn>
Subject: [PATCH 6/8] PCI: iproc: fix a leaked reference by adding missing of_node_put
Date:   Wed, 27 Feb 2019 12:40:41 +0800
Message-Id: <1551242443-27300-6-git-send-email-wen.yang99@zte.com.cn>
In-Reply-To: <1551242443-27300-1-git-send-email-wen.yang99@zte.com.cn>
References: <1551242443-27300-1-git-send-email-wen.yang99@zte.com.cn>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

The call to of_parse_phandle returns a node pointer with refcount
incremented thus it must be explicitly decremented after the last
usage.
iproc_msi_init also calls of_node_get to increase refcount
(proc_msi_init -> iproc_msi_alloc_domains -> pci_msi_create_irq_domain
-> msi_create_irq_domain -> irq_domain_create_linear -> __irq_domain_add),
so irq_domain will not be affected when it is released.

Detected by coccinelle with the following warnings:
./drivers/pci/controller/pcie-iproc.c:1323:3-9: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 1299, but without a corresponding object release within this function.
./drivers/pci/controller/pcie-iproc.c:1330:1-7: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 1299, but without a corresponding object release within this function.

Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Ray Jui <rjui@broadcom.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: linux-pci@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
---
 drivers/pci/controller/pcie-iproc.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/pcie-iproc.c b/drivers/pci/controller/pcie-iproc.c
index c20fd6b..9998c5c 100644
--- a/drivers/pci/controller/pcie-iproc.c
+++ b/drivers/pci/controller/pcie-iproc.c
@@ -1320,14 +1320,18 @@ static int iproc_pcie_msi_enable(struct iproc_pcie *pcie)
 	if (pcie->need_msi_steer) {
 		ret = iproc_pcie_msi_steer(pcie, msi_node);
 		if (ret)
-			return ret;
+			goto out_put_node;
 	}
 
 	/*
 	 * If another MSI controller is being used, the call below should fail
 	 * but that is okay
 	 */
-	return iproc_msi_init(pcie, msi_node);
+	ret = iproc_msi_init(pcie, msi_node);
+
+out_put_node:
+	of_node_put(msi_node);
+	return ret;
 }
 
 static void iproc_pcie_msi_disable(struct iproc_pcie *pcie)
-- 
2.9.5