2020-08-23 19:18:26

by Sumera Priyadarsini

Subject: [PATCH V2] net: dsa: Add of_node_put() before break statement

Every iteration of for_each_child_of_node() decrements
the reference count of the previous node, however when control
is transferred from the middle of the loop, as in the case of
a return or break or goto, there is no decrement thus ultimately
resulting in a memory leak.

Fix a potential memory leak in mt7530.c by inserting of_node_put()
before the break statement.

Issue found with Coccinelle.

---
Changes in v2:
Add another of_node_put() in for_each_child_of_node() as pointed
out by Andrew.

---

Signed-off-by: Sumera Priyadarsini <[email protected]>
---
drivers/net/dsa/mt7530.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
index 8dcb8a49ab67..e81198a65c26 100644
--- a/drivers/net/dsa/mt7530.c
+++ b/drivers/net/dsa/mt7530.c
@@ -1327,6 +1327,7 @@ mt7530_setup(struct dsa_switch *ds)
if (phy_node->parent == priv->dev->of_node->parent) {
ret = of_get_phy_mode(mac_np, &interface);
if (ret && ret != -ENODEV)
+ of_node_put(mac_np)
return ret;
id = of_mdio_parse_addr(ds->dev, phy_node);
if (id == 0)
@@ -1334,6 +1335,7 @@ mt7530_setup(struct dsa_switch *ds)
if (id == 4)
priv->p5_intf_sel = P5_INTF_SEL_PHY_P4;
}
+ of_node_put(mac_np);
of_node_put(phy_node);
break;
}
--
2.17.1

2020-08-23 19:29:33

by Andrew Lunn

Subject: Re: [PATCH V2] net: dsa: Add of_node_put() before break statement

> diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
> index 8dcb8a49ab67..e81198a65c26 100644
> --- a/drivers/net/dsa/mt7530.c
> +++ b/drivers/net/dsa/mt7530.c
> @@ -1327,6 +1327,7 @@ mt7530_setup(struct dsa_switch *ds)
> if (phy_node->parent == priv->dev->of_node->parent) {
> ret = of_get_phy_mode(mac_np, &interface);
> if (ret && ret != -ENODEV)
> + of_node_put(mac_np)
> return ret;
> id = of_mdio_parse_addr(ds->dev, phy_node);
> if (id == 0)

You are missing some { }. And a ; . I'm surprised gcc did not warn
you!

Andrew