ALSA: hda: Do not unset preset when cleaning up codec
authorCezary Rojewski <cezary.rojewski@intel.com>
Thu, 19 Jan 2023 14:32:35 +0000 (15:32 +0100)
committerTakashi Iwai <tiwai@suse.de>
Mon, 23 Jan 2023 08:11:19 +0000 (09:11 +0100)
commit87978e6ad45a16835cc58234451111091be3c59a
treebe9f470579ab6216286992d6870a1a4ec456bc9c
parentb9cee506da2b7920b5ea02ccd8e78a907d0ee7aa
ALSA: hda: Do not unset preset when cleaning up codec

Several functions that take part in codec's initialization and removal
are re-used by ASoC codec drivers implementations. Drivers mimic the
behavior of hda_codec_driver_probe/remove() found in
sound/pci/hda/hda_bind.c with their component->probe/remove() instead.

One of the reasons for that is the expectation of
snd_hda_codec_device_new() to receive a valid pointer to an instance of
struct snd_card. This expectation can be met only once sound card
components probing commences.

As ASoC sound card may be unbound without codec device being actually
removed from the system, unsetting ->preset in
snd_hda_codec_cleanup_for_unbind() interferes with module unload -> load
scenario causing null-ptr-deref. Preset is assigned only once, during
device/driver matching whereas ASoC codec driver's module reloading may
occur several times throughout the lifetime of an audio stack.

Suggested-by: Takashi Iwai <tiwai@suse.com>
Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://lore.kernel.org/r/20230119143235.1159814-1-cezary.rojewski@intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
sound/pci/hda/hda_bind.c
sound/pci/hda/hda_codec.c