linux-kernel - [PATCH 3.16 037/254] mfd: twl4030-audio: Fix sibling-node lookup

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Message-ID: <lsq.1519831218.370755581@decadent.org.uk>
Date:   Wed, 28 Feb 2018 15:20:18 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org,
        "Peter Ujfalusi" <peter.ujfalusi@...com>,
        "Lee Jones" <lee.jones@...aro.org>,
        "Johan Hovold" <johan@...nel.org>
Subject: [PATCH 3.16 037/254] mfd: twl4030-audio: Fix sibling-node lookup

3.16.55-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Johan Hovold <johan@...nel.org>

commit 0a423772de2f3d7b00899987884f62f63ae00dcb upstream.

A helper purported to look up a child node based on its name was using
the wrong of-helper and ended up prematurely freeing the parent of-node
while leaking any matching node.

To make things worse, any matching node would not even necessarily be a
child node as the whole device tree was searched depth-first starting at
the parent.

Fixes: 019a7e6b7b31 ("mfd: twl4030-audio: Add DT support")
Signed-off-by: Johan Hovold <johan@...nel.org>
Acked-by: Peter Ujfalusi <peter.ujfalusi@...com>
Signed-off-by: Lee Jones <lee.jones@...aro.org>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/mfd/twl4030-audio.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

--- a/drivers/mfd/twl4030-audio.c
+++ b/drivers/mfd/twl4030-audio.c
@@ -159,13 +159,18 @@ unsigned int twl4030_audio_get_mclk(void
 EXPORT_SYMBOL_GPL(twl4030_audio_get_mclk);
 
 static bool twl4030_audio_has_codec(struct twl4030_audio_data *pdata,
-			      struct device_node *node)
+			      struct device_node *parent)
 {
+	struct device_node *node;
+
 	if (pdata && pdata->codec)
 		return true;
 
-	if (of_find_node_by_name(node, "codec"))
+	node = of_get_child_by_name(parent, "codec");
+	if (node) {
+		of_node_put(node);
 		return true;
+	}
 
 	return false;
 }