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Date:   Wed, 6 Apr 2022 15:29:24 -0700
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Subject: Re: [PATCH] Bluetooth: hci_qca: Use del_timer_sync() before freeing
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To:     Steven Rostedt <rostedt@goodmis.org>,
        Guenter Roeck <linux@roeck-us.net>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Marcel Holtmann <marcel@holtmann.org>,
        Johan Hedberg <johan.hedberg@gmail.com>,
        Luiz Augusto von Dentz <luiz.dentz@gmail.com>,
        Ben Young Tae Kim <ytkim@qca.qualcomm.com>,
        Thomas Gleixner <tglx@linutronix.de>
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From:   Eric Dumazet <eric.dumazet@gmail.com>
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On 4/6/22 09:46, Steven Rostedt wrote:
> On Wed, 6 Apr 2022 09:36:10 -0700
> Guenter Roeck <linux@roeck-us.net> wrote:
>
>>> So we have a chicken verses egg issue here?
>>>    
>> Almost looks like it, unless I am missing something. Maybe some flag
>> is needed to prevent the timer handling code from queuing into the
>> destroyed workqueue, or the workqueue handler from updating the timer.
> That's exactly what I was thinking. I do not know all the code here. I
> could try to write a patch, but I may likely miss something.
>
> -- Steve


Take a look at

https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=1946014ca3b19be9e485e780e862c375c6f98bad


Ie, use an ->live  (or ->dead) field.