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From:   Schspa Shi <schspa@gmail.com>
To:     Tejun Heo <tj@kernel.org>
Cc:     Luiz Augusto von Dentz <luiz.dentz@gmail.com>,
        Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
        Marcel Holtmann <marcel@holtmann.org>,
        Johan Hedberg <johan.hedberg@gmail.com>,
        syzbot <syzbot+243b7d89777f90f7613b@syzkaller.appspotmail.com>,
        syzkaller-bugs@googlegroups.com,
        Lai Jiangshan <jiangshanlai@gmail.com>,
        "linux-bluetooth@vger.kernel.org" <linux-bluetooth@vger.kernel.org>
Subject: Re: [PATCH] Bluetooth: use hdev->workqueue when queuing
 hdev->{cmd,ncmd}_timer works
Date:   Mon, 05 Sep 2022 16:24:06 +0800
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Message-ID: <m2wnaixlwy.fsf@gmail.com>
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Tejun Heo <tj@kernel.org> writes:

> Hello,
>
> On Sat, Sep 03, 2022 at 07:11:18PM -0700, Luiz Augusto von Dentz wrote:
>> And we can check for __WQ_DRAINING? Anyway checking
>
> Please don't do that. That's an internal flag. It shouldn't be *that*
> difficult to avoid this without peeking into wq internal state.
>
> Thanks.

It seems we only need to change hdev->{cmd,ncmd}_timer to
hdev->workqueue, there will be no race because drain_workqueue will
flush all pending work internally.
Any new timeout work will see HCI_CMD_DRAIN_WORKQUEUE flags after we
cancel and flushed all the delayed work.

-- 
BRs
Schspa Shi