[PATCH] net: dsa: qca8k: Add of_node_put() in qca8k_setup_mdio_bus()

[PATCH] net: dsa: qca8k: Add of_node_put() in qca8k_setup_mdio_bus()

[Nishka Dasgupta]

Each iteration of for_each_available_child_of_node() puts the previous
node, but in the case of a return from the middle of the loop, there
is no put, thus causing a memory leak. Hence add an of_node_put() before
the return.
Additionally, the local variable ports in the function 
qca8k_setup_mdio_bus() takes the return value of of_get_child_by_name(),
which gets a node but does not put it. If the function returns without
putting ports, it may cause a memory leak. Hence put ports before the
mid-loop return statement, and also outside the loop after its last usage
in this function.
Issues found with Coccinelle.

Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>
---
 drivers/net/dsa/qca8k.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c
index 232e8cc96f6d..87753e4423aa 100644
--- a/drivers/net/dsa/qca8k.c
+++ b/drivers/net/dsa/qca8k.c
@@ -583,8 +583,11 @@ qca8k_setup_mdio_bus(struct qca8k_priv *priv)
 
 	for_each_available_child_of_node(ports, port) {
 		err = of_property_read_u32(port, "reg", &reg);
-		if (err)
+		if (err) {
+			of_node_put(port);
+			of_node_put(ports);
 			return err;
+		}
 
 		if (!dsa_is_user_port(priv->ds, reg))
 			continue;
@@ -595,6 +598,7 @@ qca8k_setup_mdio_bus(struct qca8k_priv *priv)
 			internal_mdio_mask |= BIT(reg);
 	}
 
+	of_node_put(ports);
 	if (!external_mdio_mask && !internal_mdio_mask) {
 		dev_err(priv->dev, "no PHYs are defined.\n");
 		return -EINVAL;
-- 
2.19.1

Re: [PATCH] net: dsa: qca8k: Add of_node_put() in qca8k_setup_mdio_bus()

[David Miller]

From: Nishka Dasgupta <nishkadg.linux@gmail.com>
Date: Sun,  4 Aug 2019 21:00:18 +0530

> Each iteration of for_each_available_child_of_node() puts the previous
> node, but in the case of a return from the middle of the loop, there
> is no put, thus causing a memory leak. Hence add an of_node_put() before
> the return.
> Additionally, the local variable ports in the function 
> qca8k_setup_mdio_bus() takes the return value of of_get_child_by_name(),
> which gets a node but does not put it. If the function returns without
> putting ports, it may cause a memory leak. Hence put ports before the
> mid-loop return statement, and also outside the loop after its last usage
> in this function.
> Issues found with Coccinelle.
> 
> Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>

Appplied.