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From: Dmitry Vyukov <dvyukov@google.com>
Date: Thu, 7 Jun 2018 19:03:23 +0200
Message-ID: <CACT4Y+Yv4_TjyJtNxso9CLBZPXCUkYZy_1RG_o6ASJdTsLO2Ng@mail.gmail.com>
Subject: Re: general protection fault in open_fs_devices
To: Anand Jain <anand.jain@oracle.com>
Cc: syzbot <syzbot+909a5177749d7990ffa4@syzkaller.appspotmail.com>, clm@fb.com,
        dsterba@suse.com, Josef Bacik <jbacik@fb.com>,
        linux-btrfs@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>
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On Wed, Jun 6, 2018 at 6:28 PM, Anand Jain <anand.jain@oracle.com> wrote:
>
>
> On 06/06/2018 09:17 PM, syzbot wrote:
>
>
>
>  Which means there was some other thread which freed our %fs_devices.
>  As this thread is still in open_ctree() so the contending thread can't
>  be the ioctl(). So btrfs_free_stale_devices() is the only thread which
>  can free our %fs_devices in this case.
>
>  This is fixed in [1] in the mailing list.
>
>  [1]
>    [PATCH 3/3] btrfs: fix race between mkfs and mount


Let's tell about this syzbot:

#syz fix: btrfs: fix race between mkfs and mount