Re: [PATCH] xfs: fix signed integer overflow

[Dave Chinner]

On Fri, Sep 09, 2016 at 03:16:48PM +0800, Xie XiuQi wrote:
> On 2016/9/9 14:42, Joe Perches wrote:
> > On Fri, 2016-09-09 at 14:38 +0800, Xie XiuQi wrote:
> >> Use 1U for unsigned long, or we'll meet a overflow issue with UBSAN.
> > 
> > trivia: misleading commit message
> > 
> > 1U is for unsigned int not unsigned long int
> > 
> 
> Sorry, my fault. Thank you for your comments.
> 
> From 9cb8e36406a54ce0eaade31dd28f6068f03de1d2 Mon Sep 17 00:00:00 2001
> From: Xie XiuQi <xiexiuqi@xxxxxxxxxx>
> Date: Tue, 6 Sep 2016 11:15:34 +0800
> Subject: [PATCH v2] xfs: fix signed integer overflow
....
> ---
>  fs/xfs/xfs_buf_item.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
> index e455f90..3a27997 100644
> --- a/fs/xfs/xfs_buf_item.c
> +++ b/fs/xfs/xfs_buf_item.c
> @@ -865,7 +865,7 @@ xfs_buf_item_log_segment(
>          */
>         if (bit) {
>                 end_bit = MIN(bit + bits_to_set, (uint)NBWORD);
> -               mask = ((1 << (end_bit - bit)) - 1) << bit;
> +               mask = ((1U << (end_bit - bit)) - 1) << bit;
>                 *wordp |= mask;
>                 wordp++;
>                 bits_set = end_bit - bit;

This patch is whitespace damaged and fails to apply. I've fixed it
up as this is a trivial change. However, please fix the problem
before you submit more patches.

Cheers,

Dave.
-- 
Dave Chinner
david@xxxxxxxxxxxxx