Re: [PATCH -next v2] block: fix wrong mode for blkdev_get_by_dev() from disk_scan_partitions()

From: Christian Brauner
Date: Tue Jun 20 2023 - 05:58:58 EST


On Sun, Jun 18, 2023 at 10:04:02PM +0800, Yu Kuai wrote:
> From: Yu Kuai <yukuai3@xxxxxxxxxx>
>
> After commit 2736e8eeb0cc ("block: use the holder as indication for
> exclusive opens"), blkdev_get_by_dev() will warn if holder is NULL and
> mode contains 'FMODE_EXCL'.
>
> holder from blkdev_get_by_dev() from disk_scan_partitions() is always NULL,
> hence it should not use 'FMODE_EXCL', which is broben by the commit. For
> consequence, WARN_ON_ONCE() will be triggered from blkdev_get_by_dev()
> if user scan partitions with device opened exclusively.
>
> Fix this problem by removing 'FMODE_EXCL' from disk_scan_partitions(),
> as it used to be.
>
> Reported-by: syzbot+00cd27751f78817f167b@xxxxxxxxxxxxxxxxxxxxxxxxx
> Link: https://syzkaller.appspot.com/bug?extid=00cd27751f78817f167b
> Fixes: 2736e8eeb0cc ("block: use the holder as indication for exclusive opens")
> Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
> ---

Looks good to me,
Reviewed-by: Christian Brauner <brauner@xxxxxxxxxx>