Re: [PATCH] md/raid10: fix divide-by-zero in setup_geo() with zero far_copies

[Yuhao Jiang]

Hi Kuai,

This report was reported by me, so Junrui added me as Reported-by.

Thanks,


On Sun, Apr 19, 2026 at 12:43 AM Yu Kuai <yukuai@xxxxxxxxx> wrote:
>
> Hi,
>
> 在 2026/4/16 11:39, Junrui Luo 写道:
> > setup_geo() extracts near_copies (nc) and far_copies (fc) from the
> > user-provided layout parameter without checking for zero. When fc=0
> > with the "improved" far set layout selected, 'geo->far_set_size =
> > disks / fc' triggers a divide-by-zero.
> >
> > Validate nc and fc immediately after extraction, returning -1 if
> > either is zero.
> >
> > Fixes: 475901aff158 ("MD RAID10: Improve redundancy for 'far' and 'offset' algorithms (part 1)")
> > Reported-by: Yuhao Jiang<danisjiang@xxxxxxxxx>
>
> So again I can't find a report, and Reported-by usually should be followed
> by a Closes link to the original report.
>
> Applied with Reported-by tag removed.
>
> > Cc:stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Junrui Luo<moonafterrain@xxxxxxxxxxx>
> > ---
> >   drivers/md/raid10.c | 2 ++
> >   1 file changed, 2 insertions(+)
>
> --
> Thansk,
> Kuai



-- 
Yuhao Jiang