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Date:   Thu, 31 Mar 2022 10:07:35 -0400
From:   Josef Bacik <josef@toxicpanda.com>
To:     Zhang Wensheng <zhangwensheng5@huawei.com>
Cc:     axboe@kernel.dk, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, nbd@other.debian.org,
        yukuai3@huawei.com
Subject: Re: [PATCH -next] nbd: fix possible overflow on 'first_minor' in
 nbd_dev_add()
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References: <20220310093224.4002895-1-zhangwensheng5@huawei.com>
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On Thu, Mar 10, 2022 at 05:32:24PM +0800, Zhang Wensheng wrote:
> 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>

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

Thanks,

Josef