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Date:   Tue, 21 Jun 2022 10:32:04 +0200
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Subject: Re: [BUG] BLE device unpairing triggers kernel panic
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To:     Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Cc:     "linux-bluetooth@vger.kernel.org" <linux-bluetooth@vger.kernel.org>,
        Marcel Holtmann <marcel@holtmann.org>,
        "regressions@lists.linux.dev" <regressions@lists.linux.dev>,
        Pengutronix Kernel Team <kernel@pengutronix.de>
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From:   Ahmad Fatoum <a.fatoum@pengutronix.de>
In-Reply-To: <CABBYNZ+8dpPBqaQMr-Hz_DJRxT-0ucCjgAJH50FUaN7Sn9H6rA@mail.gmail.com>
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Hello Luiz,

On 20.06.22 22:18, Luiz Augusto von Dentz wrote:
> On Mon, Jun 20, 2022 at 3:06 AM Ahmad Fatoum <a.fatoum@pengutronix.de> wrote:
>> Disconnect of connection #1 being processed after new connection #2
>> concluded sounds wrong. Would I be able to reconnect
>> afterwards or would all connections, but the first, be directly
>> disconnected...?
> 
> That depends on the order you have queued the commands, it will be
> processed in the exact order it is received, that why I said it is
> single queue design, and it is done like that to prevent messing up
> with states since we know the exact order the commands will be sent.
> 
>>> otherwise we need a
>>> different queue to handle command that abort/cancel other already in
>>> the queue.
>>
>> Is the revert an acceptable interim solution or are there issues
>> I am missing?
> 
> Afaik there were problem with concurrent connections request, so what
> would really help us here is to have some tests to emulate this
> scenario with our CI, in the meantime please check if the following
> fixes your problem:
> 
> https://gist.github.com/Vudentz/b4fff292c7f4ad55ca3299fd5ab797ae

Doesn't help unfortunately. First pairing works as before.
Second still fails:

  Bluetooth: hci0: Opcode 0x200d failed: -110
  Bluetooth: hci0: request failed to create LE connection: err -110

Cheers,
Ahmad

> 
>> Cheers,
>> Ahmad
>>
>>>
>>>> We've been deploying the revert for a while now and I just posted
>>>> it to the mailing list[1]. There have been other reports
>>>> of this issue with different hardware too and fixing sent_cmd
>>>> would likely be too complicated/time intensive for me.
>>>>
>>>> I am happy to test future patches that fix this properly though.
>>>>
>>>> [1]: https://lore.kernel.org/linux-bluetooth/20220616092418.738877-1-a.fatoum@pengutronix.de/T/#t
>>>>
>>>> Cheers,
>>>> Ahmad
>>>>
>>>>
>>>>
>>>>>
>>>>> Cheers,
>>>>> Ahmad
>>>>>
>>>>
>>>>
>>>> --
>>>> Pengutronix e.K.                           |                             |
>>>> Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
>>>> 31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
>>>> Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |
>>>
>>>
>>>
>>
>>
>> --
>> Pengutronix e.K.                           |                             |
>> Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
>> 31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
>> Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |
> 
> 
> 


-- 
Pengutronix e.K.                           |                             |
Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |