[PATCH] ASoC: damp: Reset dapm wcache after freeing damp widgets

[Jyri Sarha <jsarha@ti.com>]

If there is anything in damp->path_source_cache or
damp->path_sink_cache, it can not be valid after the widgets have been
freed. Without this patch a repeated remove and load of a machine
driver may cause NULL pointer reference in dapm_wcache_lookup() when a
freed widget, not belonging to any list, is haunting in the wcache.

Signed-off-by: Jyri Sarha <jsarha@ti.com>
Reported-by: Felipe Balbi <balbi@ti.com>
---
The patch fixes the problem reported here:
http://mailman.alsa-project.org/pipermail/alsa-devel/2015-October/099431.html

 sound/soc/soc-dapm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c
index ff8bda4..d78db59 100644
--- a/sound/soc/soc-dapm.c
+++ b/sound/soc/soc-dapm.c
@@ -2286,6 +2286,9 @@ static void dapm_free_widgets(struct snd_soc_dapm_context *dapm)
 			continue;
 		snd_soc_dapm_free_widget(w);
 	}
+
+	dapm->path_sink_cache.widget = NULL;
+	dapm->path_source_cache.widget = NULL;
 }
 
 static struct snd_soc_dapm_widget *dapm_find_widget(
-- 
1.9.1