tree d7d1d1e6d9cbf3f95e7d360137073dcfa78617c3
parent c9eaa447e77efe77b7fa4c953bd62de8297fd6c5
author Jarkko Nikula <jarkko.nikula@linux.intel.com> 1397570289 +0300
committer Mark Brown <broonie@linaro.org> 1398077393 +0100

ASoC: dapm: Fix widget double free with auto-disable DAPM kcontrol

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.

Fixes: 9e1fda4ae158 (ASoC: dapm: Implement mixer input auto-disable)
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
Cc: stable@vger.kernel.org