[PATCH 3/4] ASoC: Intel: check and clear runtime module pointer

[Jie Yang <yang.jie@intel.com>]

Add check runtime module pointers before freeing them, and clear
them to NULL after freed.

With this implemented, we can avoid NULL pointer dereference or
double free errors.

Signed-off-by: Jie Yang <yang.jie@intel.com>
---
 sound/soc/intel/haswell/sst-haswell-pcm.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/sound/soc/intel/haswell/sst-haswell-pcm.c b/sound/soc/intel/haswell/sst-haswell-pcm.c
index 23ae040..f97fa5a 100644
--- a/sound/soc/intel/haswell/sst-haswell-pcm.c
+++ b/sound/soc/intel/haswell/sst-haswell-pcm.c
@@ -928,10 +928,15 @@ static void hsw_pcm_free_modules(struct hsw_priv_data *pdata)
 
 	for (i = 0; i < ARRAY_SIZE(mod_map); i++) {
 		pcm_data = &pdata->pcm[mod_map[i].dai_id][mod_map[i].stream];
-		sst_hsw_runtime_module_free(pcm_data->runtime);
+		if (pcm_data->runtime){
+			sst_hsw_runtime_module_free(pcm_data->runtime);
+			pcm_data->runtime = NULL;
+		}
 	}
-	if (sst_hsw_is_module_loaded(hsw, SST_HSW_MODULE_WAVES)) {
+	if (sst_hsw_is_module_loaded(hsw, SST_HSW_MODULE_WAVES) &&
+				pdata->runtime_waves) {
 		sst_hsw_runtime_module_free(pdata->runtime_waves);
+		pdata->runtime_waves = NULL;
 	}
 }
 
-- 
1.9.1