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From: Sergey Senozhatsky <senozhatsky@chromium.org>
To: Andrew Morton <akpm@linux-foundation.org>,
	Kairui Song <kasong@tencent.com>
Cc: linux-mm@kvack.org, Minchan Kim <minchan@kernel.org>,
	Sergey Senozhatsky <senozhatsky@chromium.org>,
	linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
	Desheng Wu <deshengwu@tencent.com>,
	stable@vger.kernel.org
Subject: Re: [PATCH 1/2] zram: refuse to use zero sized block device as backing device
Date: Thu, 5 Dec 2024 16:05:52 +0900	[thread overview]
Message-ID: <20241205070552.GE16709@google.com> (raw)
In-Reply-To: <20241204180224.31069-2-ryncsn@gmail.com>

On (24/12/05 02:02), Kairui Song wrote:
> From: Kairui Song <kasong@tencent.com>
> 
> 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@tencent.com>
> Signed-off-by: Kairui Song <kasong@tencent.com>
> Cc: stable@vger.kernel.org

Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>

  reply	other threads:[~2024-12-05  7:05 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-12-04 18:02 [PATCH 0/2] zram: fix backing device setup issue Kairui Song
2024-12-04 18:02 ` [PATCH 1/2] zram: refuse to use zero sized block device as backing device Kairui Song
2024-12-05  7:05   ` Sergey Senozhatsky [this message]
2024-12-04 18:02 ` [PATCH 2/2] zram: fix uninitialized ZRAM not releasing " Kairui Song
2024-12-05  7:09   ` Sergey Senozhatsky
2024-12-09 16:52     ` Kairui Song

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