[PATCH 5.1 18/96] ASoC: hda: fix unbalanced codec dev refcount for HDA_DEV_ASOC

Greg Kroah-Hartman
2019-07-08T15:31:16Z

[ Upstream commit d6947bb234dcc86e878d502516d0fb9d635aa2ae ]

HDA_DEV_ASOC type codec device refcounts are managed differently
from HDA_DEV_LEGACY devices. The refcount is released explicitly
in snd_hdac_ext_bus_device_remove() for ASOC type devices.
So, remove the put_device() call in snd_hda_codec_dev_free()
for such devices to make the refcount balanced. This will prevent
the NULL pointer exception when the codec driver is released
after the card is freed.

Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
sound/pci/hda/hda_codec.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index b20eb7fc83eb..fcdf2cd3783b 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -840,7 +840,14 @@ static int snd_hda_codec_dev_free(struct snd_device *device)
if (codec->core.type == HDA_DEV_LEGACY)
snd_hdac_device_unregister(&codec->core);
codec_display_power(codec, false);
- put_device(hda_codec_dev(codec));
+
+ /*
+ * In the case of ASoC HD-audio bus, the device refcount is released in
+ * snd_hdac_ext_bus_device_remove() explicitly.
+ */
+ if (codec->core.type == HDA_DEV_LEGACY)
+ put_device(hda_codec_dev(codec));
+
return 0;
}

--
2.20.1