net: dsa: fix a leaked reference by adding missing of_node_put [Linux 5.0]

net: dsa: fix a leaked reference by adding missing of_node_put [Linux 5.0]

This Linux kernel change "net: dsa: fix a leaked reference by adding missing of_node_put" is included in the Linux 5.0 release. This change is authored by Wen Yang <wen.yang99 [at] zte.com.cn> on Mon Feb 25 15:22:19 2019 +0800. The commit for this change in Linux stable tree is 9919a36 (patch).

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 <[email protected]>
Reviewed-by: Vivien Didelot <[email protected]>
Cc: Andrew Lunn <[email protected]>
Cc: Vivien Didelot <[email protected]>
Cc: Florian Fainelli <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Vivien Didelot <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: David S. Miller <[email protected]>

There are 17 lines of Linux source code added/deleted in this change. Code changes to Linux kernel are as follows.

 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 a191702..410f191 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 2a2a878..c226169 100644
--- a/net/dsa/port.c
+++ b/net/dsa/port.c
@@ -292,6 +292,7 @@ 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;
 }

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