ASoC: cache: Do the codec->reg_cache zero pionter check

For the snd_soc_cache_init(), the reg_size maybe zero and then the value
of codec->reg_cache, which is alloced via kzalloc, maybe equal to
ZERO_SIZE_PTR. If the reg parameter of snd_soc_cache_write() is large enough,
the cache[idx] = val maybe cause the kernel crash...

So this patch fix this via doing the zero pionter check of it.

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

diff --git a/sound/soc/soc-cache.c b/sound/soc/soc-cache.c
index 375dc6d..bfed3e4 100644 (file)
--- a/sound/soc/soc-cache.c
+++ b/sound/soc/soc-cache.c
@@ -96,8 +96,7 @@ int snd_soc_cache_exit(struct snd_soc_codec *codec)
 {
        dev_dbg(codec->dev, "ASoC: Destroying cache for %s codec\n",
                        codec->name);
-       if (!codec->reg_cache)
-               return 0;
+
        kfree(codec->reg_cache);
        codec->reg_cache = NULL;
        return 0;
@@ -117,8 +116,9 @@ int snd_soc_cache_read(struct snd_soc_codec *codec,
                return -EINVAL;
 
        mutex_lock(&codec->cache_rw_mutex);
-       *value = snd_soc_get_cache_val(codec->reg_cache, reg,
-                                      codec->driver->reg_word_size);
+       if (!ZERO_OR_NULL_PTR(codec->reg_cache))
+               *value = snd_soc_get_cache_val(codec->reg_cache, reg,
+                                              codec->driver->reg_word_size);
        mutex_unlock(&codec->cache_rw_mutex);
 
        return 0;
@@ -136,8 +136,9 @@ int snd_soc_cache_write(struct snd_soc_codec *codec,
                        unsigned int reg, unsigned int value)
 {
        mutex_lock(&codec->cache_rw_mutex);
-       snd_soc_set_cache_val(codec->reg_cache, reg, value,
-                             codec->driver->reg_word_size);
+       if (!ZERO_OR_NULL_PTR(codec->reg_cache))
+               snd_soc_set_cache_val(codec->reg_cache, reg, value,
+                                     codec->driver->reg_word_size);
        mutex_unlock(&codec->cache_rw_mutex);
 
        return 0;