net: ethernet: ti: cpsw: Add of_node_put() before return and break
diff mbox series

Message ID 20190716054843.2957-1-nishkadg.linux@gmail.com
State New
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Series
  • net: ethernet: ti: cpsw: Add of_node_put() before return and break
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Commit Message

Nishka Dasgupta July 16, 2019, 5:48 a.m. UTC
Each iteration of for_each_available_child_of_node puts the previous
node, but in the case of a return or break from the middle of the loop,
there is no put, thus causing a memory leak.
Hence, for function cpsw_probe_dt, create an extra label err_node_put
that puts the last used node and returns ret; modify the return
statements in the loop to save the return value in ret and goto this new
label.
For function cpsw_remove_dt, add an of_node_put before the break.
Issue found with Coccinelle.

Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>
---
 drivers/net/ethernet/ti/cpsw.c | 26 ++++++++++++++++++--------
 1 file changed, 18 insertions(+), 8 deletions(-)

Comments

David Miller July 16, 2019, 7:37 p.m. UTC | #1
From: Nishka Dasgupta <nishkadg.linux@gmail.com>
Date: Tue, 16 Jul 2019 11:18:43 +0530

> Each iteration of for_each_available_child_of_node puts the previous
> node, but in the case of a return or break from the middle of the loop,
> there is no put, thus causing a memory leak.

What an incredible terribly designed loop macro, this
for_each_available_child_of_node () thing is.

A macro with non-trivial, invisible, side effects.  It requires
special handling of reference counting of objects if the loop is
terminated early.

This is so error prone.  Is it any wonder we have to go through the
entire tree fixing up nearly every use of this thing?

Instead of looking at the automated analysis of this and saying "great
here are all of these places where I can fix bugs", I would instead
appreicate it if the reaction was more like "this interface is
obviously impossible to use in a non-error-prone fashion, we should
fix it."

I guess I have no choice but to apply your fixes, but the larger issue
must be addressed instead.

Patch
diff mbox series

diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c
index f320f9a0de8b..32a89744972d 100644
--- a/drivers/net/ethernet/ti/cpsw.c
+++ b/drivers/net/ethernet/ti/cpsw.c
@@ -2570,7 +2570,7 @@  static int cpsw_probe_dt(struct cpsw_platform_data *data,
 			ret = PTR_ERR(slave_data->ifphy);
 			dev_err(&pdev->dev,
 				"%d: Error retrieving port phy: %d\n", i, ret);
-			return ret;
+			goto err_node_put;
 		}
 
 		slave_data->slave_node = slave_node;
@@ -2589,7 +2589,7 @@  static int cpsw_probe_dt(struct cpsw_platform_data *data,
 			if (ret) {
 				if (ret != -EPROBE_DEFER)
 					dev_err(&pdev->dev, "failed to register fixed-link phy: %d\n", ret);
-				return ret;
+				goto err_node_put;
 			}
 			slave_data->phy_node = of_node_get(slave_node);
 		} else if (parp) {
@@ -2607,7 +2607,8 @@  static int cpsw_probe_dt(struct cpsw_platform_data *data,
 			of_node_put(mdio_node);
 			if (!mdio) {
 				dev_err(&pdev->dev, "Missing mdio platform device\n");
-				return -EINVAL;
+				ret = -EINVAL;
+				goto err_node_put;
 			}
 			snprintf(slave_data->phy_id, sizeof(slave_data->phy_id),
 				 PHY_ID_FMT, mdio->name, phyid);
@@ -2622,7 +2623,8 @@  static int cpsw_probe_dt(struct cpsw_platform_data *data,
 		if (slave_data->phy_if < 0) {
 			dev_err(&pdev->dev, "Missing or malformed slave[%d] phy-mode property\n",
 				i);
-			return slave_data->phy_if;
+			ret = slave_data->phy_if;
+			goto err_node_put;
 		}
 
 no_phy_slave:
@@ -2633,7 +2635,7 @@  static int cpsw_probe_dt(struct cpsw_platform_data *data,
 			ret = ti_cm_get_macid(&pdev->dev, i,
 					      slave_data->mac_addr);
 			if (ret)
-				return ret;
+				goto err_node_put;
 		}
 		if (data->dual_emac) {
 			if (of_property_read_u32(slave_node, "dual_emac_res_vlan",
@@ -2648,11 +2650,17 @@  static int cpsw_probe_dt(struct cpsw_platform_data *data,
 		}
 
 		i++;
-		if (i == data->slaves)
-			break;
+		if (i == data->slaves) {
+			ret = 0;
+			goto err_node_put;
+		}
 	}
 
 	return 0;
+
+err_node_put:
+	of_node_put(slave_node);
+	return ret;
 }
 
 static void cpsw_remove_dt(struct platform_device *pdev)
@@ -2675,8 +2683,10 @@  static void cpsw_remove_dt(struct platform_device *pdev)
 		of_node_put(slave_data->phy_node);
 
 		i++;
-		if (i == data->slaves)
+		if (i == data->slaves) {
+			of_node_put(slave_node);
 			break;
+		}
 	}
 
 	of_platform_depopulate(&pdev->dev);