Re: [PATCH 1/2] zram: refuse to use zero sized block device as backing device

[Sergey Senozhatsky]

On (24/12/05 02:02), Kairui Song wrote:
> From: Kairui Song <kasong@xxxxxxxxxxx>
> 
> Setting a zero sized block device as backing device is pointless, and
> one can easily create a recursive loop by setting the uninitialized
> ZRAM device itself as its own backing device by (zram0 is uninitialized):
> 
>     echo /dev/zram0 > /sys/block/zram0/backing_dev
> 
> It's definitely a wrong config, and the module will pin itself,
> kernel should refuse doing so in the first place.
> 
> By refusing to use zero sized device we avoided misuse cases
> including this one above.
> 
> Fixes: 013bf95a83ec ("zram: add interface to specif backing device")
> Reported-by: Desheng Wu <deshengwu@xxxxxxxxxxx>
> Signed-off-by: Kairui Song <kasong@xxxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx

Reviewed-by: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>