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Date:   Mon, 12 Sep 2022 08:23:28 +0200
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Subject: Re: [Bug] [Deadlock] Kernel thread deadlock in rfcomm socket release
 when connect interrupted
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To:     Peter Sutton <peter@foxdogstudios.com>
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Cc:     Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>,
        Luiz Augusto von Dentz <luiz.dentz@gmail.com>,
        linux-bluetooth@vger.kernel.org, regressions@lists.linux.dev
From:   Paul Menzel <pmenzel@molgen.mpg.de>
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[Cc: +regressions]

#regzbot ^introduced: b7ce436a5d798bc59e71797952566608a4b4626b
#regzbot title: [Bug] [Deadlock] Kernel thread deadlock in rfcomm socket 
release when connect interrupted

Dear Pete,


Am 11.09.22 um 17:42 schrieb Peter Sutton:
> Just following this up. Is there anything I can do to help fix this?
> Running a custom kernel is a real pain. I've been running with the
> commit revert and upgrading with Arch Linux kernel releases with no
> issue.

(Please do not top post.)

Have you tested bluetooth-next already? Regardless, the offending commit 
present in Linux since 5.15-rc1 should be reverted.


Kind regards,

Paul


> On Mon, 30 May 2022 at 12:44, Peter Sutton <peter@foxdogstudios.com> wrote:
>>
>> Commit b7ce436a5d798bc59e71797952566608a4b4626b is the probable cause.
>> I compiled a custom Arch Linux kernel package [1] and the bug was
>> present. Reverting the commit fixed the bug. Below is the reply I was
>> writing before Matt found the suspect commit and I tested with the
>> custom kernel.
>>
>>> What hardware is that?
>>
>> $ dmesg | grep iwlwifi
>> Me: Intel(R) Dual Band Wireless AC 8260, REV=0x204
>> Matt: Intel(R) Dual Band Wireless AC 8265, REV=0x230
>>
>> We both get:
>>
>> $ lsusb | grep Bluetooth
>> Me & Matt: Bus 001 Device 006: ID 8087:0a2b Intel Corp. Bluetooth wireless interface
>>
>>> As a lot of patches are also applied to the stable series, do you know,
>>> if this is a regression? Does it work with Linux 5.15(.0) or 5.10?
>>
>> Bug is present on current Arch Linux LTS kernel:
>>
>> $ uname -a
>> Linux taffer 5.15.43-1-lts #1 SMP Wed, 25 May 2022 14:08:34 +0000 x86_64 GNU/Linux
>>
>> Matt tested on 5.10.115 and the bug is not present. So I guess it's a
>> regression. Anecdotally, we encountered this behaviour 1 yr ago
>> (difficult to say exactly), then it went away but came back about 1 or
>> 2 months ago. All of this is on Arch Linux, I update about once a
>> week.
>>
>> [1] https://wiki.archlinux.org/title/Kernel/Arch_Build_System