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From:   OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
To:     Dmitry Vyukov <dvyukov@google.com>
Cc:     syzbot <syzbot+6f1624f937d9d6911e2d@syzkaller.appspotmail.com>,
        Marco Elver <elver@google.com>,
        LKML <linux-kernel@vger.kernel.org>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
        syzkaller <syzkaller@googlegroups.com>
Subject: Re: KCSAN: data-race in __fat_write_inode / fat12_ent_get
References: <0000000000000cfff005a26226ce@google.com>
        <874ku0sncc.fsf@mail.parknet.co.jp>
        <CACT4Y+YaM9Qj9V9G7G+aQrmfxfdtyBX4WXXsBamUjyMMpEeEdg@mail.gmail.com>
        <877dyveq1h.fsf@mail.parknet.co.jp>
        <CACT4Y+ZQ4Uw7uP36ULiAQ_MSB8KkXhBSZhWTXZaMybn2acK1Sg@mail.gmail.com>
Date:   Tue, 07 Apr 2020 22:03:16 +0900
In-Reply-To: <CACT4Y+ZQ4Uw7uP36ULiAQ_MSB8KkXhBSZhWTXZaMybn2acK1Sg@mail.gmail.com>
        (Dmitry Vyukov's message of "Tue, 7 Apr 2020 12:39:28 +0200")
Message-ID: <874ktva1nv.fsf@mail.parknet.co.jp>
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Dmitry Vyukov <dvyukov@google.com> writes:

>> You meant I can regenerate a disk image from that log (if so, how)?
>>
>> If not, for next time, it would be helpful if syzkaller provides the log
>> to regenerate the corrupted image (or saving a corrupted image) to
>> reproduce this, then I can try to detect the corruption pattern early.
>
>
> I've converted the program to C using syz-prog2c:
> https://github.com/google/syzkaller/blob/master/docs/syzbot.md#syzkaller-reproducers
> then slightly changed the generated program to dump the file to disk
> rather than mounting.
>
> The resulting image is attached (archived because it's mostly zeros).

Thank you! I think I can see now why the generated image became the
cause of this.
-- 
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>