ASoC: dpcm: skip missing substream while applying symmetry

commit 6246f283d5e02ac757bd8d9bacde8fdc54c4582d upstream.

If for any reason, the backend does not have the requested substream
(like capture on a playback only backend), the BE will be skipped in
dpcm_be_dai_startup().

However, dpcm_apply_symmetry() does not skip those BE and will
dereference the be_substream (NULL) pointer anyway.

Like in dpcm_be_dai_startup(), just skip those BE.

Fixes: 906c7d690c3b ("ASoC: dpcm: Apply symmetry for DPCM")
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index 03f36e534050f49cf9c4a859a9bc6e93f1798503..0c1dd6bd67abcb847019e6f4abef44c9e6a92ee4 100644 (file)
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -1895,10 +1895,15 @@ static int dpcm_apply_symmetry(struct snd_pcm_substream *fe_substream,
                struct snd_soc_pcm_runtime *be = dpcm->be;
                struct snd_pcm_substream *be_substream =
                        snd_soc_dpcm_get_substream(be, stream);
-               struct snd_soc_pcm_runtime *rtd = be_substream->private_data;
+               struct snd_soc_pcm_runtime *rtd;
                struct snd_soc_dai *codec_dai;
                int i;
 
+               /* A backend may not have the requested substream */
+               if (!be_substream)
+                       continue;
+
+               rtd = be_substream->private_data;
                if (rtd->dai_link->be_hw_params_fixup)
                        continue;