[alsa-devel] Applied "ASoC: hda: fix unbalanced codec dev refcount for HDA_DEV_ASOC" to the asoc tree

[Mark Brown]

The patch

   ASoC: hda: fix unbalanced codec dev refcount for HDA_DEV_ASOC

has been applied to the asoc tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-5.2

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

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Thanks,
Mark

>From d6947bb234dcc86e878d502516d0fb9d635aa2ae Mon Sep 17 00:00:00 2001
From: Ranjani Sridharan <ranjani.sridharan at linux.intel.com>
Date: Fri, 31 May 2019 09:01:37 -0700
Subject: [PATCH] ASoC: hda: fix unbalanced codec dev refcount for HDA_DEV_ASOC

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 at linux.intel.com>
Reviewed-by: Takashi Iwai <tiwai at suse.de>
Signed-off-by: Mark Brown <broonie at 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 ec0b8595eb4d..6cdec64dc68a 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -834,7 +834,14 @@ static int snd_hda_codec_dev_free(struct snd_device *device)
 	codec->in_freeing = 1;
 	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