[PATCH v3] ASoC: SOF: Intel: Fix stream cleanup on hw free

[Cezary Rojewski]

Field "substream" gets assigned during stream setup in
hda_dsp_pcm_hw_params() but it is never cleared afterwards during
cleanup procedure. 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 hw_free 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 at intel.com>
Acked-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
---

Changes in v3:
- simple rewording of commit title & message

Changes in v2:
- relocated stream->substream assignment from _pcm_close() to _hw_free()


 sound/soc/sof/intel/hda-stream.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sound/soc/sof/intel/hda-stream.c b/sound/soc/sof/intel/hda-stream.c
index 7daa913dbde0..5d386956906f 100644
--- a/sound/soc/sof/intel/hda-stream.c
+++ b/sound/soc/sof/intel/hda-stream.c
@@ -547,6 +547,8 @@ int hda_dsp_stream_hw_free(struct snd_sof_dev *sdev,
 					SOF_HDA_REG_PP_PPCTL, mask, 0);
 	spin_unlock_irq(&bus->reg_lock);
 
+	stream->substream = NULL;
+
 	return 0;
 }
 
-- 
2.17.1