[PATCH] fix: net: ti: cpsw_init_common: fix excess of_node_put on parent node when cpts child not found

[WenTao Liang]

When no "cpts" child node exists in the device tree, cpts_node is
  assigned cpsw->dev->of_node without taking a reference via of_node_get.
  The function then unconditionally calls of_node_put(cpts_node) at the
  end, causing an excess put on the parent device node which can lead to a
  refcount underflow.

Use of_node_get when falling back to the parent node to ensure the
  reference count is properly balanced with the subsequent of_node_put.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: ed3525eda4c4 ("net: ethernet: ti: introduce cpsw switchdev based driver part 1 - dual-emac")
Signed-off-by: WenTao Liang <vulab@xxxxxxxxxxx>
---
 drivers/net/ethernet/ti/cpsw_priv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/ti/cpsw_priv.c b/drivers/net/ethernet/ti/cpsw_priv.c
index 1f6f374551cb..b20567f96d78 100644
--- a/drivers/net/ethernet/ti/cpsw_priv.c
+++ b/drivers/net/ethernet/ti/cpsw_priv.c
@@ -553,7 +553,7 @@ int cpsw_init_common(struct cpsw_common *cpsw, void __iomem *ss_regs,
 
 	cpts_node = of_get_child_by_name(cpsw->dev->of_node, "cpts");
 	if (!cpts_node)
-		cpts_node = cpsw->dev->of_node;
+		cpts_node = of_node_get(cpsw->dev->of_node);
 
 	cpsw->cpts = cpts_create(cpsw->dev, cpts_regs, cpts_node,
 				 CPTS_N_ETX_TS);
-- 
2.39.5 (Apple Git-154)