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Message-ID: <577c7140-a30c-ca06-a81e-c791e44b1321@pengutronix.de>
Date:   Thu, 7 Jul 2022 07:45:16 +0200
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Subject: Re: [BUG] BLE device unpairing triggers kernel panic
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To:     Thorsten Leemhuis <regressions@leemhuis.info>,
        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>,
        Tedd Ho-Jeong An <hj.tedd.an@gmail.com>
References: <a1ce1743-e450-6cdb-dfab-56a3e3eb9aed@pengutronix.de>
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From:   Ahmad Fatoum <a.fatoum@pengutronix.de>
In-Reply-To: <b7b080ff-a5da-a10c-674b-c3bb653f0aeb@leemhuis.info>
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Hi,

On 04.07.22 14:11, Thorsten Leemhuis wrote:
> Hi, this is your Linux kernel regression tracker. Top-posting for once,
> to make this easily accessible to everyone.
> 
> Looks like the discussions to fix this regression got stuck. What can be
> done to get thing rolling again? Or has progress been made and I just
> missed it? Ciao, Thorsten

No progress has been made as far as I am aware. I am reverting the commit
introducing the regression on my systems and haven't yet had the time to
debug this further to help find an alternative solution.

Cheers,
Ahmad

> 
> On 24.06.22 21:59, Luiz Augusto von Dentz wrote:
>> On Fri, Jun 24, 2022 at 5:53 AM Ahmad Fatoum <a.fatoum@pengutronix.de> wrote:
>>> On 21.06.22 20:52, Luiz Augusto von Dentz wrote:
>>>> On Tue, Jun 21, 2022 at 1:32 AM Ahmad Fatoum <a.fatoum@pengutronix.de> wrote:
>>>>> 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
>>>>
>>>> Can we try to add a test in mgmt-tester to reproduce the error above?
>>>
>>> I am not familiar with mgmt-tester. What information do you
>>> need to reproduce? In the meantime, can we revert the commit?
>>> I understand that this may break other uses, but I believe
>>> previously working stuff should have precedence..
>>
>> Have a looks at:
>>
>> https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/doc/test-runner.txt
>>
>> And then run with:
>>
>> sudo tools/test-runner -k <pathyto/bzImage> -- tools/mgmt-tester
>>
>> Btw, can we have the exact steps to reproduce it using bluetoothctl if possible?
>>
>>> Cheers,
>>> Ahmad
>>>
>>>>
>>>>> 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
> 


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