ASoC: mt8173-rt5650: fix child-node lookup

Web:        https://git.kernel.org/torvalds/c/3a0a7b261009a9eaebd84140e933ee579df18d0c
Commit:     3a0a7b261009a9eaebd84140e933ee579df18d0c
Parent:     4fbd8d194f06c8a3fd2af1ce560ddb31f7ec8323
Refname:    refs/heads/master
Author:     Johan Hovold <[email protected]>
AuthorDate: Wed Jan 31 16:59:21 2018 +1100
Committer:  Mark Brown <[email protected]>
CommitDate: Wed Feb 7 11:16:39 2018 +0000

    ASoC: mt8173-rt5650: fix child-node lookup
    
    This driver used the wrong OF-helper when looking up the optional
    capture-codec child node during probe. Instead of searching just
    children of the sound node, a tree-wide depth-first search starting at
    the unrelated platform node was done. Not only could this end up
    matching an unrelated node or no node at all; the platform node could
    also be prematurely freed since of_find_node_by_name() drops a reference
    to its first argument. This particular pattern has been observed leading
    to crashes after probe deferrals in other drivers.
    
    Fix this by dropping the broken call to of_find_node_by_name() and
    keeping only the second, correct lookup using of_get_child_by_name()
    while taking care not to bail out if the optional node is missing.
    
    Note that this also addresses two capture-codec node-reference leaks
    (one for each of the original helper calls).
    
    Compile tested only.
    
    Fixes: d349caeb0510 ("ASoC: mediatek: Add second I2S on mt8173-rt5650 machine driver")
    Signed-off-by: Johan Hovold <[email protected]>
    Signed-off-by: Mark Brown <[email protected]>
---
 sound/soc/mediatek/mt8173/mt8173-rt5650.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/sound/soc/mediatek/mt8173/mt8173-rt5650.c b/sound/soc/mediatek/mt8173/mt8173-rt5650.c
index e69c141d8ed4..45fc2d2640ae 100644
--- a/sound/soc/mediatek/mt8173/mt8173-rt5650.c
+++ b/sound/soc/mediatek/mt8173/mt8173-rt5650.c
@@ -274,15 +274,10 @@ static int mt8173_rt5650_dev_probe(struct platform_device *pdev)
 	}
 	mt8173_rt5650_codecs[1].of_node = mt8173_rt5650_codecs[0].of_node;
 
-	if (of_find_node_by_name(platform_node, "codec-capture")) {
-		np = of_get_child_by_name(pdev->dev.of_node, "codec-capture");
-		if (!np) {
-			dev_err(&pdev->dev,
-				"%s: Can't find codec-capture DT node\n",
-				__func__);
-			return -EINVAL;
-		}
+	np = of_get_child_by_name(pdev->dev.of_node, "codec-capture");
+	if (np) {
 		ret = snd_soc_of_get_dai_name(np, &codec_capture_dai);
+		of_node_put(np);
 		if (ret < 0) {
 			dev_err(&pdev->dev,
 				"%s codec_capture_dai name fail %d\n",
--
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