linux-kernel - Re: [PATCH] brd: fix overflow in __brd_direct

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Message-ID: <fb12beef-6c0e-5c13-ab95-29683243f095@kernel.dk>
Date:   Wed, 13 Sep 2017 11:18:18 -0600
From:   Jens Axboe <axboe@...nel.dk>
To:     Mikulas Patocka <mpatocka@...hat.com>,
        Dan Williams <dan.j.williams@...el.com>
Cc:     linux-block@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] brd: fix overflow in __brd_direct_access

On 09/13/2017 07:17 AM, Mikulas Patocka wrote:
> The code in __brd_direct_access multiplies the pgoff variable by page size
> and divides it by 512. It can cause overflow on 32-bit architectures. The
> overflow happens if we create ramdisk larger than 4G and use it as a
> sparse device.
> 
> This patch replaces multiplication and division with multiplication by the
> number of sectors per page.

Thanks, applied with Dan's ack.

-- 
Jens Axboe