[PATCH] ASoC: SOF: Intel: Fix stream cleanup on pcm close

[Cezary Rojewski <cezary.rojewski@intel.com>]

Field "substream" gets assigned during stream setup in
hda_dsp_pcm_hw_params() but it is never cleared afterwards during
hda_dsp_pcm_close(). Now, any non-pcm operation e.g.: compress can
mistakenly make use of that pointer as it's bypassing all
"if (s->substream)" checks.

Nulling the pointer during close operation ensures no wild pointers are
left behind.

Fixes: cdae3b9a47aa ("ASoC: SOF: Intel: Add Intel specific HDA PCM operations")
Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
---
 sound/soc/sof/intel/hda-pcm.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/sound/soc/sof/intel/hda-pcm.c b/sound/soc/sof/intel/hda-pcm.c
index a46a6baa1c3f..4b3a89cf20e7 100644
--- a/sound/soc/sof/intel/hda-pcm.c
+++ b/sound/soc/sof/intel/hda-pcm.c
@@ -246,5 +246,6 @@ int hda_dsp_pcm_close(struct snd_sof_dev *sdev,
 
 	/* unbinding pcm substream to hda stream */
 	substream->runtime->private_data = NULL;
+	hstream->substream = NULL;
 	return 0;
 }
-- 
2.17.1