[PATCH] ASoC: dapm: delete dapm_kcontrol_data paths list before freeing it

From: Srinivas Kandagatla
Date: Mon Jun 04 2018 - 07:13:26 EST


dapm_kcontrol_data is freed as part of dapm_kcontrol_free(), leaving the
paths pointer dangling in the list.

This leads to system crash when we try to unload and reload sound card.
I hit this bug during ADSP crash/reboot test case on Dragon board DB410c.

Without this patch, on SLAB Poisoning enabled build, kernel crashes with
"BUG kmalloc-128 (Tainted: G W ): Poison overwritten"

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
sound/soc/soc-dapm.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c
index 1e9a36389667..36a39ba30226 100644
--- a/sound/soc/soc-dapm.c
+++ b/sound/soc/soc-dapm.c
@@ -433,6 +433,8 @@ 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);
+
+ list_del(&data->paths);
kfree(data->wlist);
kfree(data);
}
--
2.17.0