[PATCH AUTOSEL 4.4 38/63] ALSA: PCM: check if ops are defined before suspending PCM

Sasha Levin
2019-03-27T18:24:38Z

From: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>

[ 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>
---
sound/core/pcm_native.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 9b6dcdea4431..4eb0c2f48638 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -1335,6 +1335,14 @@ 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;
--
2.19.1