ASoC: dapm: Lock during userspace access

[ Upstream commit d90d06680f8287f11a5ad6d83680790e5da86f08 ]

commit e50b1e06b79e9d51efbff9627b4dd407184ef43f upstream.

The DAPM lock must be held when accessing the DAPM graph status through
sysfs or debugfs, otherwise concurrent changes to the graph can result in
undefined behaviour.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c
index 943e6a9a6319756fe87e2bfcdbdb3d96f79fb431..34e5d8253c24b7f4404834f379c4c9ce27f0158a 100644 (file)
--- a/sound/soc/soc-dapm.c
+++ b/sound/soc/soc-dapm.c
@@ -1854,6 +1854,7 @@ static ssize_t dapm_widget_power_read_file(struct file *file,
                                           size_t count, loff_t *ppos)
 {
        struct snd_soc_dapm_widget *w = file->private_data;
+       struct snd_soc_card *card = w->dapm->card;
        char *buf;
        int in, out;
        ssize_t ret;
@@ -1863,6 +1864,8 @@ static ssize_t dapm_widget_power_read_file(struct file *file,
        if (!buf)
                return -ENOMEM;
 
+       mutex_lock(&card->dapm_mutex);
+
        in = is_connected_input_ep(w, NULL);
        dapm_clear_walk_input(w->dapm, &w->sources);
        out = is_connected_output_ep(w, NULL);
@@ -1905,6 +1908,8 @@ static ssize_t dapm_widget_power_read_file(struct file *file,
                                        p->sink->name);
        }
 
+       mutex_unlock(&card->dapm_mutex);
+
        ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
 
        kfree(buf);
@@ -2165,11 +2170,15 @@ static ssize_t dapm_widget_show(struct device *dev,
        struct snd_soc_pcm_runtime *rtd = dev_get_drvdata(dev);
        int i, count = 0;
 
+       mutex_lock(&rtd->card->dapm_mutex);
+
        for (i = 0; i < rtd->num_codecs; i++) {
                struct snd_soc_codec *codec = rtd->codec_dais[i]->codec;
                count += dapm_widget_show_codec(codec, buf + count);
        }
 
+       mutex_unlock(&rtd->card->dapm_mutex);
+
        return count;
 }