ASoC: mediatek: common: handle NULL case in suspend/resume function

When memory allocation for afe->reg_back_up fails, reg_back_up can't
be used.
Keep the suspend/resume flow but skip register backup when
afe->reg_back_up is NULL, in case illegal memory access happens.

Fixes: 283b612429a2 ("ASoC: mediatek: implement mediatek common structure")
Signed-off-by: Trevor Wu <trevor.wu@mediatek.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20210910092613.30188-1-trevor.wu@mediatek.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/mediatek/common/mtk-afe-fe-dai.c b/sound/soc/mediatek/common/mtk-afe-fe-dai.c
index baaa588..e95c7c0 100644 (file)
--- a/sound/soc/mediatek/common/mtk-afe-fe-dai.c
+++ b/sound/soc/mediatek/common/mtk-afe-fe-dai.c
@@ -334,9 +334,11 @@ int mtk_afe_suspend(struct snd_soc_component *component)
                        devm_kcalloc(dev, afe->reg_back_up_list_num,
                                     sizeof(unsigned int), GFP_KERNEL);
 
-       for (i = 0; i < afe->reg_back_up_list_num; i++)
-               regmap_read(regmap, afe->reg_back_up_list[i],
-                           &afe->reg_back_up[i]);
+       if (afe->reg_back_up) {
+               for (i = 0; i < afe->reg_back_up_list_num; i++)
+                       regmap_read(regmap, afe->reg_back_up_list[i],
+                                   &afe->reg_back_up[i]);
+       }
 
        afe->suspended = true;
        afe->runtime_suspend(dev);
@@ -356,12 +358,13 @@ int mtk_afe_resume(struct snd_soc_component *component)
 
        afe->runtime_resume(dev);
 
-       if (!afe->reg_back_up)
+       if (!afe->reg_back_up) {
                dev_dbg(dev, "%s no reg_backup\n", __func__);
-
-       for (i = 0; i < afe->reg_back_up_list_num; i++)
-               mtk_regmap_write(regmap, afe->reg_back_up_list[i],
-                                afe->reg_back_up[i]);
+       } else {
+               for (i = 0; i < afe->reg_back_up_list_num; i++)
+                       mtk_regmap_write(regmap, afe->reg_back_up_list[i],
+                                        afe->reg_back_up[i]);
+       }
 
        afe->suspended = false;
        return 0;