Re: [BUG] BLE device unpairing triggers kernel panic

From: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
To: Ahmad Fatoum <a.fatoum@pengutronix.de>
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>
Subject: Re: [BUG] BLE device unpairing triggers kernel panic
Date: Tue, 21 Jun 2022 11:52:09 -0700	[thread overview]
Message-ID: <CABBYNZLdy-rndKczoG_WiWXQmacX+vzCbftQKvzJ3B6imtZopw@mail.gmail.com> (raw)
In-Reply-To: <1d1b76cf-df6f-3935-5cd2-c45ea78f2c33@pengutronix.de>

Hi Ahmad, Tedd,

On Tue, Jun 21, 2022 at 1:32 AM Ahmad Fatoum <a.fatoum@pengutronix.de> wrote:
>
> 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

Can we try to add a test in mgmt-tester to reproduce the error above?

> 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 |

-- 
Luiz Augusto von Dentz