[alsa-devel] [PATCH v2] 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@linux.intel.com --- 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; }
On Fri, 31 May 2019 18:01:37 +0200, Ranjani Sridharan wrote:
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
FWIW, snd_hdac_ext_bus_device_remove() is called at the machine driver remove callback that is called from soc_remove_dai_linkes() in soc_cleanup_card_resources(). There, the order is assured that snd_card_free() gets called at first, so this change should be correct -- the HD-audio codec object gets freed at a later point for ASoC.
thanks,
Takashi
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.
You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed.
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Thanks, Mark
From d6947bb234dcc86e878d502516d0fb9d635aa2ae Mon Sep 17 00:00:00 2001
From: Ranjani Sridharan ranjani.sridharan@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@linux.intel.com Reviewed-by: Takashi Iwai tiwai@suse.de Signed-off-by: Mark Brown broonie@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; }
participants (3)
-
Mark Brown -
Ranjani Sridharan -
Takashi Iwai