[PATCH 3.18 50/85] ASoC: dapm: delete dapm_kcontrol_data paths list before freeing it

From: Greg Kroah-Hartman
Date: Sun Jul 01 2018 - 12:13:20 EST

3.18-stable review patch. If anyone has any objections, please let me know.


From: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>

commit ff2faf1289c1f81b5b26b9451dd1c2006aac8db8 upstream.

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
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

sound/soc/soc-dapm.c | 2 ++
1 file changed, 2 insertions(+)

--- a/sound/soc/soc-dapm.c
+++ b/sound/soc/soc-dapm.c
@@ -254,6 +254,8 @@ static int dapm_kcontrol_data_alloc(stru
static void dapm_kcontrol_free(struct snd_kcontrol *kctl)
struct dapm_kcontrol_data *data = snd_kcontrol_chip(kctl);
+ list_del(&data->paths);