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From:   Jiacheng Xu <578001344xu@gmail.com>
Date:   Tue, 30 Aug 2022 21:33:03 +0800
Message-ID: <CAO4S-me0tq289wabwsL4xbRXfHgaetqvExt8+ZyrKLxfGzLteA@mail.gmail.com>
Subject: possible deadlock in io_poll_double_wake
To:     linux-kernel@vger.kernel.org, axboe@kernel.dk,
        asml.silence@gmail.com, Qiang.Zhang@windriver.com
Cc:     io-uring@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Hello,

When using modified Syzkaller to fuzz the Linux kernel-5.19, the
following crash was triggered. Though the issue seems to get fixed on
syzbot(https://syzkaller.appspot.com/bug?id=12e4415bf5272f433acefa690478208f3be3be2d),
it could still be triggered with the following repro.
We would appreciate a CVE ID if this is a security issue.

HEAD commit: 568035b01cfb Linux-5.15.58
git tree: upstream

console output:
https://drive.google.com/file/d/1e4DHaUKhY9DLZJK_pNScWHydUv-MaD9_/view?usp=sharing
https://drive.google.com/file/d/1NmOGWcfPnY2kSrS0nOwvG1AZ923jFQ3p/view?usp=sharing
kernel config: https://drive.google.com/file/d/1wgIUDwP5ho29AM-K7HhysSTfWFpfXYkG/view?usp=sharing
syz repro: https://drive.google.com/file/d/1e5xY8AOMimLbpAlOOupmGYC_tUA3sa8k/view?usp=sharing
C reproducer: https://drive.google.com/file/d/1esAe__18Lt7and43QdXFfI6GJCsF85_z/view?usp=sharing

Description:
spin_lock_irqsave() in __wake_up_common_lock() is called before waking
up a task. However, spin_lock_irqsave() has to be called once in
io_poll_double_wake().
such call stack is:

   snd_pcm_post_stop()
      __wake_up_common_lock()
         spin_lock_irqsave()
             io_poll_double_wake()
                 spin_lock_irqsave()

Environment:
Ubuntu 20.04 on Linux 5.4.0
QEMU 4.2.1:
qemu-system-x86_64 \
  -m 2G \
  -smp 2 \
  -kernel /home/workdir/bzImage \
  -append "console=ttyS0 root=/dev/sda earlyprintk=serial net.ifnames=0" \
  -drive file=/home/workdir/stretch.img,format=raw \
  -net user,host=10.0.2.10,hostfwd=tcp:127.0.0.1:10021-:22 \
  -net nic,model=e1000 \
  -enable-kvm \
  -nographic \
  -pidfile vm.pid \
  2>&1 | tee vm.log

If you fix this issue, please add the following tag to the commit:
Reported-by Jiacheng Xu<578001344xu@gmail.com>