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Date: Tue, 19 Dec 2023 18:23:32 +0100
From: Wolfram Sang <wsa@kernel.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
Subject: Re: [PATCH v2] i2c: rk3x: fix potential spinlock recursion on poll
Message-ID: <ZYHRlMukbJUZw7cO@shikoro>
Mail-Followup-To: Wolfram Sang <wsa@kernel.org>,
	Jensen Huang <jensenhuang@friendlyarm.com>,
	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,
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On Thu, Dec 07, 2023 at 04:21:59PM +0800, 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)
>=20
> Store the IRQ number and disable/enable it around the polling transfer.
> This patch has been tested on NanoPC-T4.
>=20
> Signed-off-by: Jensen Huang <jensenhuang@friendlyarm.com>
> Reviewed-by: Heiko Stuebner <heiko@sntech.de>
> Reviewed-by: Andi Shyti <andi.shyti@kernel.org>

Applied to for-current, thanks!

But I'd like to see the follow-up patches somewhen which have been
discussed in this thread.


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