On 04/15/2014 03:58 PM, Jarkko Nikula wrote:

Commit 9e1fda4ae158 ("ASoC: dapm: Implement mixer input auto-disable") is trying to free the widget it allocated by snd_soc_dapm_new_control() call in dapm_kcontrol_data_alloc() by adding kfree(data->widget) to dapm_kcontrol_free().

This is causing a widget double free with auto-disabled DAPM kcontrols in sound card unregistration because widgets are already freed before dapm_kcontrol_free() is called.

Reason for that is all widgets are added into dapm->card->widgets list in snd_soc_dapm_new_control() and freed in dapm_free_widgets() during execution of snd_soc_dapm_free().

Now snd_soc_dapm_free() calls for different DAPM contexts happens before snd_card_free() call from where the call chain to dapm_kcontrol_free() begins:

soc_cleanup_card_resources() soc_remove_dai_links() soc_remove_link_dais() snd_soc_dapm_free(&cpu_dai->dapm) soc_remove_link_components() soc_remove_platform() snd_soc_dapm_free(&platform->dapm) soc_remove_codec() snd_soc_dapm_free(&codec->dapm) snd_soc_dapm_free(&card->dapm) snd_card_free() snd_card_do_free() snd_device_free_all() snd_device_free() snd_ctl_dev_free() snd_ctl_remove() snd_ctl_free_one() dapm_kcontrol_free()

This wasn't making harm with ordinary DAPM kcontrols since data->widget is NULL for them.

Signed-off-by: Jarkko Nikula jarkko.nikula@linux.intel.com Cc: stable stable@vger.kernel.org # 3.12+

Acked-by: Lars-Peter Clausen lars@metafoo.de

Thanks.

---

sound/soc/soc-dapm.c | 1 - 1 file changed, 1 deletion(-)

diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c index c8a780d0d057..7769b0a2bc5a 100644 --- a/sound/soc/soc-dapm.c +++ b/sound/soc/soc-dapm.c @@ -254,7 +254,6 @@ static int dapm_kcontrol_data_alloc(struct snd_soc_dapm_widget *widget, static void dapm_kcontrol_free(struct snd_kcontrol *kctl) { struct dapm_kcontrol_data *data = snd_kcontrol_chip(kctl);

• kfree(data->widget); kfree(data->wlist); kfree(data); }