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SubjectRe: [PATCH] staging:iio: Use kcalloc instead of kzalloc to allocate array
On Tue, Nov 29, 2011 at 10:08:00PM +0100, Thomas Meyer wrote:
> The advantage of kcalloc is, that will prevent integer overflows which could
> result from the multiplication of number of elements and size and it is also
> a bit nicer to read.
>
> The semantic patch that makes this change is available
> in https://lkml.org/lkml/2011/11/25/107
>
> Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
> ---
>
> diff -u -p a/drivers/staging/iio/accel/lis3l02dq_ring.c b/drivers/staging/iio/accel/lis3l02dq_ring.c
> --- a/drivers/staging/iio/accel/lis3l02dq_ring.c 2011-11-13 11:07:47.933826988 +0100
> +++ b/drivers/staging/iio/accel/lis3l02dq_ring.c 2011-11-28 20:00:44.704446880 +0100
> @@ -93,8 +93,7 @@ static int lis3l02dq_read_all(struct iio
> struct spi_message msg;
> int ret, i, j = 0;
>
> - xfers = kzalloc((buffer->scan_count) * 2
> - * sizeof(*xfers), GFP_KERNEL);
> + xfers = kcalloc((buffer->scan_count) * 2, sizeof(*xfers), GFP_KERNEL);

I've looked at these and none of them can actually overflow.

But if they could then there would still be the potential for
overflow here. If buffer->scan_count were a negative number then
the first for loop could cause memory corruption.

Still it's a cleanup and the patch is fine.

regards,
dan carpenter
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