Messages in this thread | | | Date | Thu, 29 Sep 2011 09:59:13 +0800 | Subject | Re: [PATCH 2/2] ASoC: Add BUG() assertion if max98095_get_bq_channel returns -EINVAL | From | Dave Young <> |
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On Thu, Sep 29, 2011 at 9:52 AM, Ryan Mallon <rmallon@gmail.com> wrote: > On 29/09/11 11:35, Dave Young wrote: > >> On Thu, Sep 29, 2011 at 7:19 AM, Ryan Mallon <rmallon@gmail.com> wrote: >>> On 29/09/11 00:02, Axel Lin wrote: >>>> The callers use the return value of max98095_get_bq_channel as array index to >>>> access max98095->dai[] array. >>>> Add BUG() assertion for out of bound access of max98095->dai[] array. >>> >>> Same here, fix the problem in the callers. >>> >>> ---- >>> Check the return value of max98095_get_bq_channel in the callers and >>> propagate any errors up. Remove the BUG_ON(channel > 1) since >>> max98095_get_bq_channel never returns a value larger than 1. >>> >>> Signed-off-by: Ryan Mallon <rmallon@gmail.com> >>> --- >>> >>> diff --git a/sound/soc/codecs/max98095.c b/sound/soc/codecs/max98095.c >>> index 668434d..55eccea 100644 >>> --- a/sound/soc/codecs/max98095.c >>> +++ b/sound/soc/codecs/max98095.c >>> @@ -2014,7 +2014,8 @@ static int max98095_put_bq_enum(struct snd_kcontrol *kcontrol, >>> int fs, best, best_val, i; >>> int regmask, regsave; >>> >>> - BUG_ON(channel > 1); >>> + if (channel < 0) >>> + return channel; >> >> If use BUG() happens in max98095_get_bq_channel, it will not return here? > > > Not quite sure what you mean?
I means if Axel Lin's patch applied, and CONFIG_BUG is on, it will panic firstly the if condition will be never entered.
> > If CONFIG_BUG was not enabled for the original version, then it would > not return at the BUG_ON and would either crash or cause odd behaviour > if it tried to index channel as -1. > > My patch is removing the BUG_ON and replacing it with a proper check and > return. It doesn't need to check > 1 since max98095_get_bq_channel never > returns that. > > My understanding is that device drivers, in general, should not call > BUG. BUG is for unrecoverable errors which leave the kernel in some > unstable state. Here we can just return an error code.
Agree
> > ~Ryan > >> >>> >>> if (!pdata || !max98095->bq_textcnt) >>> return 0; >>> @@ -2069,6 +2070,9 @@ static int max98095_get_bq_enum(struct snd_kcontrol *kcontrol, >>> int channel = max98095_get_bq_channel(kcontrol->id.name); >>> struct max98095_cdata *cdata; >>> >>> + if (channel < 0) >>> + return channel; >>> + >>> cdata = &max98095->dai[channel]; >>> ucontrol->value.enumerated.item[0] = cdata->bq_sel; >>> >>> >>> -- >>> 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/ >>> >> >> >> > > >
-- Regards Dave -- 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/
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