Re: [PATCH -next v3 5/6] nbd: fix possible overflow on 'first_minor' in nbd_dev_add()

[Josef Bacik <josef@toxicpanda.com>]

On Sat, May 21, 2022 at 03:37:48PM +0800, Yu Kuai wrote:
> From: Zhang Wensheng <zhangwensheng5@huawei.com>
> 
> 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@huawei.com>
> Signed-off-by: Yu Kuai <yukuai3@huawei.com>

Reviewed-by: Josef Bacik <josef@toxicpanda.com>

Thanks,

Josef