linux-kernel - Re: [PATCH] iio: core: Fix suspicious sizeof usage

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Date:   Thu, 27 Apr 2017 06:32:22 +0100
From:   Jonathan Cameron <jic23@...nel.org>
To:     Orson Zhai <orson.zhai@...eadtrum.com>, knaack.h@....de,
        lars@...afoo.de, pmeerw@...erw.net
Cc:     linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] iio: core: Fix suspicious sizeof usage

On 25/04/17 02:16, Orson Zhai wrote:
> Pointer size is variours in different system, say 32bit for 4 and 64bit
> for 8. The 'sizeof(infomask)' may lead to wrong bit numbers.
> 
> Signed-off-by: Orson Zhai <orson.zhai@...eadtrum.com>
That's certainly been there a while.  oops.

Anyhow, whilst clearly garbage, it doesn't actually have an effect
at the moment due to the relatively small number of bits that can be
set and the fact this is limited by 32 bit platforms anyway.

So applied to the togreg branch of iio.git and pushed out as
testing for the auto builders to play with it.

Thanks,

Jonathan
> ---
>  drivers/iio/industrialio-core.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> index 3ff91e0..795f53c 100644
> --- a/drivers/iio/industrialio-core.c
> +++ b/drivers/iio/industrialio-core.c
> @@ -1089,7 +1089,7 @@ static int iio_device_add_info_mask_type(struct iio_dev *indio_dev,
>  {
>  	int i, ret, attrcount = 0;
>  
> -	for_each_set_bit(i, infomask, sizeof(infomask)*8) {
> +	for_each_set_bit(i, infomask, sizeof(*infomask)*8) {
>  		if (i >= ARRAY_SIZE(iio_chan_info_postfix))
>  			return -EINVAL;
>  		ret = __iio_add_chan_devattr(iio_chan_info_postfix[i],
> @@ -1118,7 +1118,7 @@ static int iio_device_add_info_mask_type_avail(struct iio_dev *indio_dev,
>  	int i, ret, attrcount = 0;
>  	char *avail_postfix;
>  
> -	for_each_set_bit(i, infomask, sizeof(infomask) * 8) {
> +	for_each_set_bit(i, infomask, sizeof(*infomask) * 8) {
>  		avail_postfix = kasprintf(GFP_KERNEL,
>  					  "%s_available",
>  					  iio_chan_info_postfix[i]);
>