From: Dragan Simic <dsimic@manjaro.org>
To: Jensen Huang <jensenhuang@friendlyarm.com>
Cc: Heiko Stuebner <heiko@sntech.de>,
Andi Shyti <andi.shyti@kernel.org>,
linux-arm-kernel@lists.infradead.org,
linux-rockchip@lists.infradead.org, linux-i2c@vger.kernel.org,
linux-kernel@vger.kernel.org,
Dmitry Osipenko <dmitry.osipenko@collabora.com>,
Chris Morgan <macroalpha82@gmail.com>,
Benjamin Bara <bbara93@gmail.com>
Subject: Re: [PATCH v2] i2c: rk3x: fix potential spinlock recursion on poll
Date: Thu, 07 Dec 2023 15:10:29 +0100 [thread overview]
Message-ID: <5e11553952c02ad20591992be4284bbd@manjaro.org> (raw)
In-Reply-To: <CAMpZ1qHUnTDQ78gdrQF9Sx_-XfLM-B+H-0bL1-+twKsno+JOvg@mail.gmail.com>
On 2023-12-07 10:25, Jensen Huang wrote:
> On Thu, Dec 7, 2023 at 4:37 PM Dragan Simic <dsimic@manjaro.org> wrote:
>>
>> On 2023-12-07 09:21, Jensen Huang wrote:
>> > Possible deadlock scenario (on reboot):
>> > rk3x_i2c_xfer_common(polling)
>> > -> rk3x_i2c_wait_xfer_poll()
>> > -> rk3x_i2c_irq(0, i2c);
>> > --> spin_lock(&i2c->lock);
>> > ...
>> > <rk3x i2c interrupt>
>> > -> rk3x_i2c_irq(0, i2c);
>> > --> spin_lock(&i2c->lock); (deadlock here)
>> >
>> > Store the IRQ number and disable/enable it around the polling transfer.
>> > This patch has been tested on NanoPC-T4.
>>
>> In case you haven't already seen the related discussion linked below,
>> please have a look. I also added more people to the list of
>> recipients,
>> in an attempt to make everyone aware of the different approaches to
>> solving this issue.
>>
>> https://lore.kernel.org/all/655177f4.050a0220.d85c9.3ba0@mx.google.com/T/#m6fc9c214452fec6681843e7f455978c35c6f6c8b
>
> Thank you for providing the information. I hadn't seen this link
> before.
> After carefully looking into the related discussion, it appears that
> Dmitry Osipenko is already working on a suitable patch. To avoid
> duplication
> or conflicts, my patch can be discarded.
Thank you for responding so quickly. Perhaps it would be best to hear
from Dmitry as well, before discarding anything. It's been a while
since Dmitry wrote about working on the patch, so he might have
abandoned it.
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next prev parent reply other threads:[~2023-12-07 14:11 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-07 8:21 [PATCH v2] i2c: rk3x: fix potential spinlock recursion on poll Jensen Huang
2023-12-07 8:37 ` Dragan Simic
2023-12-07 9:25 ` Jensen Huang
2023-12-07 14:10 ` Dragan Simic [this message]
2023-12-07 16:00 ` Dmitry Osipenko
2023-12-08 8:53 ` Jensen Huang
2023-12-08 12:17 ` Dmitry Osipenko
2023-12-22 8:22 ` Jensen Huang
2023-12-19 17:23 ` Wolfram Sang
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