On Tue, Feb 21, 2023 at 02:04:49AM +0800, wenyang.linux@xxxxxxxxxxx wrote:
> From: Zhang Wensheng <zhangwensheng5@xxxxxxxxxx>
>
> commit 858f1bf65d3d9c00b5e2d8ca87dc79ed88267c98 upstream.
>
> When 'index' is a big numbers, it may become negative which forced
> to 'int'. then 'index << part_shift' might overflow to a positive
> value that is not greater than '0xfffff', then sysfs might complains
> about duplicate creation. Because of this, move the 'index' judgment
> to the front will fix it and be better.
>
> Fixes: b0d9111a2d53 ("nbd: use an idr to keep track of nbd devices")
> Fixes: 940c264984fd ("nbd: fix possible overflow for 'first_minor' in nbd_dev_add()")
> Signed-off-by: Zhang Wensheng <zhangwensheng5@xxxxxxxxxx>
> Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
> Reviewed-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
> Link: https://lore.kernel.org/r/20220521073749.3146892-6-yukuai3@xxxxxxxxxx
> Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx # v5.10+
> Signed-off-by: Wen Yang <wenyang.linux@xxxxxxxxxxx>
> ---
> drivers/block/nbd.c | 23 ++++++++++++-----------
> 1 file changed, 12 insertions(+), 11 deletions(-)
This is also needed in 5.15.y, please be more careful, you do not want
to have a regression when moving to a newer kernel version.
I've queued it up there as well.
thanks,
greg k-h
