Re: [PATCH] mtd: lpddr: Added literal suffix

Miquel Raynal
2022-11-17T14:12:01Z

Hi Denis,

arefev@swemel.ru wrote on Thu, 17 Nov 2022 15:36:25 +0300:

> The value of an arithmetic expression
> 1 << lpddr->qinfo->DevSizeShift is subject to overflow
> due to a failure to cast operands to a larger data
> type before perfoming arithmetic
>
> Signed-off-by: Denis Arefev <arefev@swemel.ru>
> ---
> drivers/mtd/lpddr/lpddr_cmds.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/lpddr/lpddr_cmds.c b/drivers/mtd/lpddr/lpddr_cmds.c
> index ee063baed136..360b2af8340b 100644
> --- a/drivers/mtd/lpddr/lpddr_cmds.c
> +++ b/drivers/mtd/lpddr/lpddr_cmds.c
> @@ -61,7 +61,7 @@ struct mtd_info *lpddr_cmdset(struct map_info *map)
> mtd->_point = lpddr_point;
> mtd->_unpoint = lpddr_unpoint;
> }
> - mtd->size = 1 << lpddr->qinfo->DevSizeShift;
> + mtd->size = 1UL << lpddr->qinfo->DevSizeShift;

Are you sure it should not be 1ULL instead? otherwise I don't see how
the overflow can happen?

> mtd->erasesize = 1 << lpddr->qinfo->UniformBlockSizeShift;
> mtd->writesize = 1 << lpddr->qinfo->BufSizeShift;
>

Thanks,
Miquèl

______________________________________________________
Linux MTD discussion mailing list