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From: John Ogness <john.ogness@linutronix.de>
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To: Ryo Takakura <ryotkkr98@gmail.com>, alex@ghiti.fr,
 aou@eecs.berkeley.edu, bigeasy@linutronix.de, conor.dooley@microchip.com,
 gregkh@linuxfoundation.org, jirislaby@kernel.org, palmer@dabbelt.com,
 paul.walmsley@sifive.com, pmladek@suse.com, samuel.holland@sifive.com,
 u.kleine-koenig@baylibre.com
Cc: linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
 linux-serial@vger.kernel.org, stable@vger.kernel.org, Ryo Takakura
 <ryotkkr98@gmail.com>
Subject: Re: [PATCH v3] serial: sifive: lock port in startup()/shutdown()
 callbacks
In-Reply-To: <20250412001847.183221-1-ryotkkr98@gmail.com>
References: <20250412001847.183221-1-ryotkkr98@gmail.com>
Date: Tue, 15 Apr 2025 09:48:06 +0206
Message-ID: <84r01tooq9.fsf@jogness.linutronix.de>
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On 2025-04-12, Ryo Takakura <ryotkkr98@gmail.com> wrote:
> startup()/shutdown() callbacks access SIFIVE_SERIAL_IE_OFFS.
> The register is also accessed from write() callback.
>
> If console were printing and startup()/shutdown() callback
> gets called, its access to the register could be overwritten.
>
> Add port->lock to startup()/shutdown() callbacks to make sure
> their access to SIFIVE_SERIAL_IE_OFFS is synchronized against
> write() callback.
>
> Fixes: 45c054d0815b ("tty: serial: add driver for the SiFive UART")
> Signed-off-by: Ryo Takakura <ryotkkr98@gmail.com>
> Reviewed-by: Petr Mladek <pmladek@suse.com>

Reviewed-by: John Ogness <john.ogness@linutronix.de>