2020-08-24 20:04:23

by Sumera Priyadarsini

Subject: [PATCH V4] net: dsa: mt7530: Add of_node_put() before break and return statements

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 and return statements.

Issue found with Coccinelle.

Signed-off-by: Sumera Priyadarsini <[email protected]>
---
Changes in v2:
Add another of_node_put() in for_each_child_of_node() as
pointed out by Andrew.

Changes in v3:
- Correct syntax errors
- Modify commit message

Changes in v4:
- Change commit prefix to include the driver name,
mt7530, as pointed out by Vladimir.
- Change the signoff to the correct format.

---
drivers/net/dsa/mt7530.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
index 8dcb8a49ab67..4b4701c69fe1 100644
--- a/drivers/net/dsa/mt7530.c
+++ b/drivers/net/dsa/mt7530.c
@@ -1326,14 +1326,17 @@ 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)
+ if (ret && ret != -ENODEV) {
+ of_node_put(mac_np);
return ret;
+ }
id = of_mdio_parse_addr(ds->dev, phy_node);
if (id == 0)
priv->p5_intf_sel = P5_INTF_SEL_PHY_P0;
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

2020-08-25 14:49:44

by David Miller

Subject: Re: [PATCH V4] net: dsa: mt7530: Add of_node_put() before break and return statements

From: Sumera Priyadarsini <[email protected]>
Date: Tue, 25 Aug 2020 01:33:11 +0530

> 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 and return statements.
>
> Issue found with Coccinelle.
>
> Signed-off-by: Sumera Priyadarsini <[email protected]>

Applied, thank you.