Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751570AbaB1G6M (ORCPT ); Fri, 28 Feb 2014 01:58:12 -0500 Received: from smtp-out-127.synserver.de ([212.40.185.127]:1055 "EHLO smtp-out-167.synserver.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751334AbaB1G6K (ORCPT ); Fri, 28 Feb 2014 01:58:10 -0500 X-SynServer-TrustedSrc: 1 X-SynServer-AuthUser: lars@metafoo.de X-SynServer-PPID: 9354 Message-ID: <53103399.5070202@metafoo.de> Date: Fri, 28 Feb 2014 07:58:33 +0100 From: Lars-Peter Clausen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20131103 Icedove/17.0.10 MIME-Version: 1.0 To: Xiubo Li CC: broonie@kernel.org, lgirdwood@gmail.com, tiwai@suse.de, alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org Subject: Re: [alsa-devel] [PATCH] ASoC: cache: Do the codec->reg_cache zero pionter check References: <1393555699-12752-1-git-send-email-Li.Xiubo@freescale.com> In-Reply-To: <1393555699-12752-1-git-send-email-Li.Xiubo@freescale.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 > --- > 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; > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/