linux-kernel - [PATCH v2] net: dsa: fix a leaked reference by adding missing of_node

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Date:   Mon, 25 Feb 2019 15:22:19 +0800
From:   Wen Yang <wen.yang99@....com.cn>
To:     andrew@...n.ch
Cc:     vivien.didelot@...il.com, f.fainelli@...il.com,
        davem@...emloft.net, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, wang.yi59@....com.cn,
        Wen Yang <wen.yang99@....com.cn>
Subject: [PATCH v2] net: dsa: fix a leaked reference by adding missing of_node_put

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:
./net/dsa/port.c:294:1-7: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 284, but without a corresponding object release within this function.
./net/dsa/dsa2.c:627:3-9: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 618, but without a corresponding object release within this function.
./net/dsa/dsa2.c:630:3-9: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 618, but without a corresponding object release within this function.
./net/dsa/dsa2.c:636:3-9: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 618, but without a corresponding object release within this function.
./net/dsa/dsa2.c:639:1-7: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 618, but without a corresponding object release within this function.

Signed-off-by: Wen Yang <wen.yang99@....com.cn>
Reviewed-by: Vivien Didelot <vivien.didelot@...il.com>
Reviewed-by: "David S. Miller" <davem@...emloft.net>
Cc: Andrew Lunn <andrew@...n.ch>
Cc: Vivien Didelot <vivien.didelot@...il.com>
Cc: Florian Fainelli <f.fainelli@...il.com>
Cc: "David S. Miller" <davem@...emloft.net>
Cc: Vivien Didelot <vivien.didelot@...il.com>
Cc: netdev@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
---
v2->v1: preserve the reverse christmas tree ordering of variables.

 net/dsa/dsa2.c | 16 ++++++++++------
 net/dsa/port.c |  1 +
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index 8c431e0..c00ee464 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -612,8 +612,8 @@ static int dsa_switch_parse_ports_of(struct dsa_switch *ds,
 {
 	struct device_node *ports, *port;
 	struct dsa_port *dp;
+	int err = 0;
 	u32 reg;
-	int err;

 	ports = of_get_child_by_name(dn, "ports");
 	if (!ports) {
@@ -624,19 +624,23 @@ static int dsa_switch_parse_ports_of(struct dsa_switch *ds,
 	for_each_available_child_of_node(ports, port) {
 		err = of_property_read_u32(port, "reg", &reg);
 		if (err)
-			return err;
+			goto out_put_node;

-		if (reg >= ds->num_ports)
-			return -EINVAL;
+		if (reg >= ds->num_ports) {
+			err = -EINVAL;
+			goto out_put_node;
+		}

 		dp = &ds->ports[reg];

 		err = dsa_port_parse_of(dp, port);
 		if (err)
-			return err;
+			goto out_put_node;
 	}

-	return 0;
+out_put_node:
+	of_node_put(ports);
+	return err;
 }

 static int dsa_switch_parse_member_of(struct dsa_switch *ds,
diff --git a/net/dsa/port.c b/net/dsa/port.c
index 2d7e01b..a6d9a04 100644
--- a/net/dsa/port.c
+++ b/net/dsa/port.c
@@ -291,6 +291,7 @@ static struct phy_device *dsa_port_get_phy_device(struct dsa_port *dp)
 		return ERR_PTR(-EPROBE_DEFER);
 	}

+	of_node_put(phy_dn);
 	return phydev;
 }

-- 
2.9.5