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List:       git-commits-head
Subject:    ASoC: dapm: Fix widget double free with auto-disable DAPM kcontrol
From:       "Linux Kernel Mailing List" <linux-kernel () vger ! kernel ! org>
Date:       2014-04-30 15:36:28
Message-ID: 20140430153628.2B914660394 () gitolite ! kernel ! org
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Gitweb:     http://git.kernel.org/linus/;a=commit;h=2697e4fb9209dfe1d1b24c92d254158f63d4bc8e
Commit:     2697e4fb9209dfe1d1b24c92d254158f63d4bc8e
Parent:     c9eaa447e77efe77b7fa4c953bd62de8297fd6c5
Author:     Jarkko Nikula <jarkko.nikula@linux.intel.com>
AuthorDate: Tue Apr 15 16:58:09 2014 +0300
Committer:  Mark Brown <broonie@linaro.org>
CommitDate: Mon Apr 21 11:49:53 2014 +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
---
 sound/soc/soc-dapm.c |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)

diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c
index c8a780d..7769b0a 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);
 }
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