[alsa-devel] [PATCH 3/6] ASoC: simple-card: Fix of-node refcount unbalance in DAI-link parser

[Takashi Iwai]

The function simple_for_each_link() has a few missing places that
forgot unrefereing of-nodes after the use.  The main do-while loop
may abort when loop=0, and this leaves the node object still
referenced.  A similar leak is found in the error handling of NULL
codec that aborts the loop as well.  Last but not least, the inner
for_each_child_of_node() loop may abort in the middle, and this leaks
the refcount of the iterator node.

This patch addresses these missing refcount issues.

Cc: Kuninori Morimoto <kuninori.morimoto.gx at renesas.com>
Signed-off-by: Takashi Iwai <tiwai at suse.de>
---

Only compile-tested.  Please review carefully.  Thanks!

 sound/soc/generic/simple-card.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/sound/soc/generic/simple-card.c b/sound/soc/generic/simple-card.c
index 3e677dd1137e..30ae0a5281b3 100644
--- a/sound/soc/generic/simple-card.c
+++ b/sound/soc/generic/simple-card.c
@@ -442,6 +442,7 @@ static int simple_for_each_link(struct simple_priv *priv,
 	struct device_node *top = dev->of_node;
 	struct device_node *node;
 	bool is_top = 0;
+	int ret = 0;
 
 	/* Check if it has dai-link */
 	node = of_get_child_by_name(top, PREFIX "dai-link");
@@ -456,13 +457,14 @@ static int simple_for_each_link(struct simple_priv *priv,
 		struct device_node *codec;
 		struct device_node *np;
 		int num = of_get_child_count(node);
-		int ret;
 
 		/* get codec */
 		codec = of_get_child_by_name(node, is_top ?
 					     PREFIX "codec" : "codec");
-		if (!codec)
-			return -ENODEV;
+		if (!codec) {
+			ret = -ENODEV;
+			goto error;
+		}
 
 		of_node_put(codec);
 
@@ -485,14 +487,18 @@ static int simple_for_each_link(struct simple_priv *priv,
 			else
 				ret = func_noml(priv, np, codec, li, is_top);
 
-			if (ret < 0)
-				return ret;
+			if (ret < 0) {
+				of_node_put(np);
+				goto error;
+			}
 		}
 
 		node = of_get_next_child(top, node);
 	} while (!is_top && node);
 
-	return 0;
+ error:
+	of_node_put(node);
+	return ret;
 }
 
 static int simple_parse_aux_devs(struct device_node *node,
-- 
2.16.4