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Date:   Mon, 4 Jan 2021 11:53:20 +0100
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Damien Le Moal <damien.lemoal@wdc.com>
Cc:     stable@vger.kernel.org, Jens Axboe <axboe@kernel.dk>
Subject: Re: [PATCH] null_blk: Fix zone size initialization
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 <20210104061044.664481-1-damien.lemoal@wdc.com>
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On Mon, Jan 04, 2021 at 03:10:44PM +0900, Damien Le Moal wrote:
> commit 0ebcdd702f49aeb0ad2e2d894f8c124a0acc6e23 upstream.
> 
> For a null_blk device with zoned mode enabled is currently initialized
> with a number of zones equal to the device capacity divided by the zone
> size, without considering if the device capacity is a multiple of the
> zone size. If the zone size is not a divisor of the capacity, the zones
> end up not covering the entire capacity, potentially resulting is out
> of bounds accesses to the zone array.
> 
> Fix this by adding one last smaller zone with a size equal to the
> remainder of the disk capacity divided by the zone size if the capacity
> is not a multiple of the zone size. For such smaller last zone, the zone
> capacity is also checked so that it does not exceed the smaller zone
> size.

Now queued up, thanks.

greg k-h