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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Liam Girdwood <liam.r.girdwood@linux.intel.com>,
        Mark Brown <broonie@kernel.org>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.9 49/94] ASoC: dapm: Fix potential DAI widget pointer deref when linking DAIs
Date:   Tue,  2 Oct 2018 06:25:03 -0700
Message-Id: <20181002132503.897310861@linuxfoundation.org>
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4.9-stable review patch.  If anyone has any objections, please let me know.

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

From: Liam Girdwood <liam.r.girdwood@linux.intel.com>

[ Upstream commit e01b4f624278d5efe5fb5da585ca371947b16680 ]

Sometime a component or topology may configure a DAI widget with no
private data leading to a dev_dbg() dereferencne of this data.

Fix this to check for non NULL private data and let users know if widget
is missing DAI.

Signed-off-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 sound/soc/soc-dapm.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- a/sound/soc/soc-dapm.c
+++ b/sound/soc/soc-dapm.c
@@ -3913,6 +3913,13 @@ int snd_soc_dapm_link_dai_widgets(struct
 			continue;
 		}
 
+		/* let users know there is no DAI to link */
+		if (!dai_w->priv) {
+			dev_dbg(card->dev, "dai widget %s has no DAI\n",
+				dai_w->name);
+			continue;
+		}
+
 		dai = dai_w->priv;
 
 		/* ...find all widgets with the same stream and link them */