[PATCH] net: dsa: mv88e6xxx: chip: Add of_node_put() before return

[PATCH] net: dsa: mv88e6xxx: chip: Add of_node_put() before return

[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.
Issue found with Coccinelle.

Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>
---
 drivers/net/dsa/mv88e6xxx/chip.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 6b17cd961d06..c97dea4599a8 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -2721,6 +2721,7 @@ static int mv88e6xxx_mdios_register(struct mv88e6xxx_chip *chip,
 			err = mv88e6xxx_mdio_register(chip, child, true);
 			if (err) {
 				mv88e6xxx_mdios_unregister(chip);
+				of_node_put(child);
 				return err;
 			}
 		}
-- 
2.19.1

Re: [PATCH] net: dsa: mv88e6xxx: chip: Add of_node_put() before return

[David Miller]

From: Nishka Dasgupta <nishkadg.linux@gmail.com>
Date: Tue, 23 Jul 2019 16:13:07 +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.
> Issue found with Coccinelle.
> 
> Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>

Applied, but as I've repeatedly stated these OF node looping constructs
are EXTREMELY ERROR PRONE.

We must fix these kinds of interfaces so that they are easier to use
correctly.