Messages in this thread Patch in this message | | | Date | Fri, 28 Feb 2014 07:58:33 +0100 | From | Lars-Peter Clausen <> | Subject | Re: [alsa-devel] [PATCH] ASoC: cache: Do the codec->reg_cache zero pionter check |
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On 02/28/2014 03:48 AM, Xiubo Li wrote: > 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... >
There are actually no users of snd_soc_cache_{read,write}() left. Since all drivers using snd_soc_set_cache_io() are now using native regmap the path in hw_{read,write} that does call snd_soc_cache_{read,write}() is never hit.
If you want to avoid this theoretical issue just remove the functions.
> So this patch fix this via doing the zero pionter check of it. > > Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com> > --- > sound/soc/soc-cache.c | 13 +++++++------ > 1 file changed, 7 insertions(+), 6 deletions(-) > > diff --git a/sound/soc/soc-cache.c b/sound/soc/soc-cache.c > index 375dc6d..bfed3e4 100644 > --- 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; >
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