[PATCH net v3] net: thunder: bgx: Fix resource leaks in device_for_each_child_node() loops

[PATCH net v3] net: thunder: bgx: Fix resource leaks in device_for_each_child_node() loops

[Wang Ming]

The device_for_each_child_node() loop in bgx_init_of_phy()
function should have fwnode_handle_put() before break which could
avoid resource leaks. This patch could fix this bug.

Fixes: eee326fd8334 ("net: thunderx: bgx: Use standard firmware node infrastructure.")
Signed-off-by: Wang Ming <machel@vivo.com>
---
 drivers/net/ethernet/cavium/thunder/thunder_bgx.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/cavium/thunder/thunder_bgx.c b/drivers/net/ethernet/cavium/thunder/thunder_bgx.c
index a317feb8decb..f8a8b2ab72aa 100644
--- a/drivers/net/ethernet/cavium/thunder/thunder_bgx.c
+++ b/drivers/net/ethernet/cavium/thunder/thunder_bgx.c
@@ -1469,6 +1469,7 @@ static int bgx_init_of_phy(struct bgx *bgx)
 	struct fwnode_handle *fwn;
 	struct device_node *node = NULL;
 	u8 lmac = 0;
+	int err = 0;
 
 	device_for_each_child_node(&bgx->pdev->dev, fwn) {
 		struct phy_device *pd;
@@ -1479,7 +1480,7 @@ static int bgx_init_of_phy(struct bgx *bgx)
 		 */
 		node = to_of_node(fwn);
 		if (!node)
-			break;
+			goto out_handle_put;
 
 		of_get_mac_address(node, bgx->lmac[lmac].mac);
 
@@ -1501,10 +1502,8 @@ static int bgx_init_of_phy(struct bgx *bgx)
 		}
 
 		lmac++;
-		if (lmac == bgx->max_lmac) {
-			of_node_put(node);
-			break;
-		}
+		if (lmac == bgx->max_lmac)
+			goto out_node_put;
 	}
 	return 0;
 
@@ -1519,8 +1518,12 @@ static int bgx_init_of_phy(struct bgx *bgx)
 		}
 		lmac--;
 	}
+	err = -EPROBE_DEFER;
+out_node_put:
 	of_node_put(node);
-	return -EPROBE_DEFER;
+out_handle_put:
+	fwnode_handle_put(fwn);
+	return err;
 }
 
 #else
-- 
2.25.1

Re: [PATCH net v3] net: thunder: bgx: Fix resource leaks in device_for_each_child_node() loops

[Paolo Abeni]

On Fri, 2023-07-14 at 15:06 +0200, Markus Elfring wrote:
> > The device_for_each_child_node() loop in bgx_init_of_phy()
> > function should have fwnode_handle_put() before break which could
> > avoid resource leaks. This patch could fix this bug.
> 
> Are imperative change descriptions still preferred?

Yes. The commit message should be re-phrased.

More importantly, it looks like the relevant reference is already
released by of_node_put() and the additional fwnode_handle_put() will
cause a reference underflow.

This patch does not look correct to me.

Cheers,

Paolo