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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,
        Ranjani Sridharan <ranjani.sridharan@linux.intel.com>,
        Ajit Kumar Pandey <AjitKumar.Pandey@amd.com>,
        Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>,
        Mark Brown <broonie@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.16 0768/1039] ASoC: SOF: ipc: Add null pointer check for substream->runtime
Date:   Mon, 24 Jan 2022 19:42:37 +0100
Message-Id: <20220124184151.127977893@linuxfoundation.org>
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From: Ajit Kumar Pandey <AjitKumar.Pandey@amd.com>

[ Upstream commit 182b682b9ab1348e07ea1bf9d8f2505cc67f9237 ]

When pcm stream is stopped "substream->runtime" pointer will be set
to NULL by ALSA core. In case host received an ipc msg from firmware
of type IPC_STREAM_POSITION after pcm stream is stopped, there will
be kernel NULL pointer exception in ipc_period_elapsed(). This patch
fixes it by adding NULL pointer check for "substream->runtime".

Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Signed-off-by: Ajit Kumar Pandey <AjitKumar.Pandey@amd.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20211216232422.345164-3-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 sound/soc/sof/ipc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sound/soc/sof/ipc.c b/sound/soc/sof/ipc.c
index e6c53c6c470e4..ca30c506a0fd6 100644
--- a/sound/soc/sof/ipc.c
+++ b/sound/soc/sof/ipc.c
@@ -547,7 +547,8 @@ static void ipc_period_elapsed(struct snd_sof_dev *sdev, u32 msg_id)
 
 	if (spcm->pcm.compress)
 		snd_sof_compr_fragment_elapsed(stream->cstream);
-	else if (!stream->substream->runtime->no_period_wakeup)
+	else if (stream->substream->runtime &&
+		 !stream->substream->runtime->no_period_wakeup)
 		/* only inform ALSA for period_wakeup mode */
 		snd_sof_pcm_period_elapsed(stream->substream);
 }
-- 
2.34.1