Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
In-Reply-To: <0000000000006971fa05769d22f6@google.com>
References: <0000000000006971fa05769d22f6@google.com>
From:   Miklos Szeredi <miklos@szeredi.hu>
Date:   Mon, 24 Sep 2018 16:44:58 +0200
Message-ID: <CAJfpegu9hZjJOUa7wHAj9KiTpcUuitsqnEMYvQzp6Mha2Yat-g@mail.gmail.com>
Subject: Re: WARNING in request_end
To:     Kirill Tkhai <ktkhai@virtuozzo.com>
Cc:     syzbot <syzbot+ef054c4d3f64cd7f7cec@syzkaller.appspotmail.com>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, Sep 24, 2018 at 2:29 PM, syzbot
<syzbot+ef054c4d3f64cd7f7cec@syzkaller.appspotmail.com> wrote:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit:    6bf4ca7fbc85 Linux 4.19-rc5
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=159149c6400000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=22a62640793a83c9
> dashboard link: https://syzkaller.appspot.com/bug?extid=ef054c4d3f64cd7f7cec
> compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
>
> Unfortunately, I don't have any reproducer for this crash yet.
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+ef054c4d3f64cd7f7cec@syzkaller.appspotmail.com
>
> WARNING: CPU: 0 PID: 9445 at fs/fuse/dev.c:390 request_end+0x82e/0xaa0

And  there we have the bug likely caused by the set_bit(FR_SENT, ...)
not being inside the fpq->lock-ed region.

So that needs to be fixed anyway, apparently.

Thanks,
Miklos