ALSA: PCM: check if ops are defined before suspending PCM

[ Upstream commit d9c0b2afe820fa3b3f8258a659daee2cc71ca3ef ]

BE dai links only have internal PCM's and their substream ops may
not be set. Suspending these PCM's will result in their
 ops->trigger() being invoked and cause a kernel oops.
So skip suspending PCM's if their ops are NULL.

[ NOTE: this change is required now for following the recent PCM core
  change to get rid of snd_pcm_suspend() call.  Since DPCM BE takes
  the runtime carried from FE while keeping NULL ops, it can hit this
  bug.  See details at:
     https://github.com/thesofproject/linux/pull/582
  -- tiwai ]

Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index e1138e7..f5eb10f 100644 (file)
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -1346,6 +1346,14 @@ int snd_pcm_suspend_all(struct snd_pcm *pcm)
                        /* FIXME: the open/close code should lock this as well */
                        if (substream->runtime == NULL)
                                continue;
+
+                       /*
+                        * Skip BE dai link PCM's that are internal and may
+                        * not have their substream ops set.
+                        */
+                       if (!substream->ops)
+                               continue;
+
                        err = snd_pcm_suspend(substream);
                        if (err < 0 && err != -EBUSY)
                                return err;