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

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

[Sumera Priyadarsini]

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.

Signed-off-by: Sumera Priyadarsini <sylphrenadin@gmail.com>
---
 drivers/net/dsa/mt7530.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
index 8dcb8a49ab67..af83e5034842 100644
--- a/drivers/net/dsa/mt7530.c
+++ b/drivers/net/dsa/mt7530.c
@@ -1334,6 +1334,7 @@ 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

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

[Andrew Lunn]

On Sun, Aug 23, 2020 at 07:31:16PM +0530, Sumera Priyadarsini wrote:
> 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.
> 
> Signed-off-by: Sumera Priyadarsini <sylphrenadin@gmail.com>
> ---
>  drivers/net/dsa/mt7530.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/net/dsa/mt7530.c b/drivers/net/dsa/mt7530.c
> index 8dcb8a49ab67..af83e5034842 100644
> --- a/drivers/net/dsa/mt7530.c
> +++ b/drivers/net/dsa/mt7530.c
> @@ -1334,6 +1334,7 @@ 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;
>  		}

Within the same loop is:

                       if (phy_node->parent == priv->dev->of_node->parent) {
                                ret = of_get_phy_mode(mac_np, &interface);
                                if (ret && ret != -ENODEV)
                                        return ret;


shouldn't this also have a put?

	  Andrew