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From: Jiri Slaby <jirislaby@kernel.org>
To: Wentao Liang <vulab@iscas.ac.cn>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Neil Armstrong <neil.armstrong@linaro.org>,
	Kevin Hilman <khilman@baylibre.com>,
	Jerome Brunet <jbrunet@baylibre.com>,
	Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc: linux-serial@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-amlogic@lists.infradead.org
Subject: Re: [PATCH] serial: meson: unregister the UART driver if port registration fails
Date: Wed, 4 Nov 2026 08:02:33 +0100	[thread overview]
Message-ID: <5b741c90-4e57-425e-b3ef-b8d10eac1f33@kernel.org> (raw)
In-Reply-To: <20261104021501.1468500-1-vulab@iscas.ac.cn>

On 04. 11. 26, 3:15, Wentao Liang wrote:
> meson_uart_probe() registers the shared uart_driver on the first port and
> relies on meson_uart_remove() to unregister it once the last port is
> removed.  If uart_add_one_port() fails, probe returns an error, so remove
> is never called and the driver stays registered, leaking its tty driver
> and per-port state.
> 
> Remember whether this probe registered the driver and unregister it again
> when adding the port fails.
> 
> Fixes: e71aab9d6132 ("tty: serial: meson: apply ttyS devname instead of ttyAML for new SoCs")
> Cc: stable@vger.kernel.org
> Assisted-by: DeepSeek-V4.1-Flash and OpenAI Codex
> Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>

makes sense to me:
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>


> ---
>   drivers/tty/serial/meson_uart.c | 7 ++++++-
>   1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/tty/serial/meson_uart.c b/drivers/tty/serial/meson_uart.c
> index a6cb2a535f9d..a51362f73dee 100644
> --- a/drivers/tty/serial/meson_uart.c
> +++ b/drivers/tty/serial/meson_uart.c
> @@ -702,6 +702,7 @@ static int meson_uart_probe(struct platform_device *pdev)
>   	int ret = 0;
>   	int irq;
>   	bool has_rtscts;
> +	bool registered = false;
>   
>   	if (pdev->dev.of_node)
>   		pdev->id = of_alias_get_id(pdev->dev.of_node, "serial");
> @@ -753,6 +754,7 @@ static int meson_uart_probe(struct platform_device *pdev)
>   		if (ret)
>   			return dev_err_probe(&pdev->dev, ret,
>   					     "can't register uart driver\n");
> +		registered = true;
>   	}
>   
>   	port->iotype = UPIO_MEM;
> @@ -781,8 +783,11 @@ static int meson_uart_probe(struct platform_device *pdev)
>   	}
>   
>   	ret = uart_add_one_port(uart_driver, port);
> -	if (ret)
> +	if (ret) {
>   		meson_ports[pdev->id] = NULL;
> +		if (registered)
> +			uart_unregister_driver(uart_driver);
> +	}
>   
>   	return ret;
>   }


-- 
js
suse labs

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WARNING: multiple messages have this Message-ID (diff)
From: Jiri Slaby <jirislaby@kernel.org>
To: Wentao Liang <vulab@iscas.ac.cn>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Neil Armstrong <neil.armstrong@linaro.org>,
	Kevin Hilman <khilman@baylibre.com>,
	Jerome Brunet <jbrunet@baylibre.com>,
	Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc: linux-serial@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-amlogic@lists.infradead.org
Subject: Re: [PATCH] serial: meson: unregister the UART driver if port registration fails
Date: Wed, 4 Nov 2026 08:02:33 +0100	[thread overview]
Message-ID: <5b741c90-4e57-425e-b3ef-b8d10eac1f33@kernel.org> (raw)
In-Reply-To: <20261104021501.1468500-1-vulab@iscas.ac.cn>

On 04. 11. 26, 3:15, Wentao Liang wrote:
> meson_uart_probe() registers the shared uart_driver on the first port and
> relies on meson_uart_remove() to unregister it once the last port is
> removed.  If uart_add_one_port() fails, probe returns an error, so remove
> is never called and the driver stays registered, leaking its tty driver
> and per-port state.
> 
> Remember whether this probe registered the driver and unregister it again
> when adding the port fails.
> 
> Fixes: e71aab9d6132 ("tty: serial: meson: apply ttyS devname instead of ttyAML for new SoCs")
> Cc: stable@vger.kernel.org
> Assisted-by: DeepSeek-V4.1-Flash and OpenAI Codex
> Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>

makes sense to me:
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>


> ---
>   drivers/tty/serial/meson_uart.c | 7 ++++++-
>   1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/tty/serial/meson_uart.c b/drivers/tty/serial/meson_uart.c
> index a6cb2a535f9d..a51362f73dee 100644
> --- a/drivers/tty/serial/meson_uart.c
> +++ b/drivers/tty/serial/meson_uart.c
> @@ -702,6 +702,7 @@ static int meson_uart_probe(struct platform_device *pdev)
>   	int ret = 0;
>   	int irq;
>   	bool has_rtscts;
> +	bool registered = false;
>   
>   	if (pdev->dev.of_node)
>   		pdev->id = of_alias_get_id(pdev->dev.of_node, "serial");
> @@ -753,6 +754,7 @@ static int meson_uart_probe(struct platform_device *pdev)
>   		if (ret)
>   			return dev_err_probe(&pdev->dev, ret,
>   					     "can't register uart driver\n");
> +		registered = true;
>   	}
>   
>   	port->iotype = UPIO_MEM;
> @@ -781,8 +783,11 @@ static int meson_uart_probe(struct platform_device *pdev)
>   	}
>   
>   	ret = uart_add_one_port(uart_driver, port);
> -	if (ret)
> +	if (ret) {
>   		meson_ports[pdev->id] = NULL;
> +		if (registered)
> +			uart_unregister_driver(uart_driver);
> +	}
>   
>   	return ret;
>   }


-- 
js
suse labs

  parent reply	other threads:[~2026-11-04  7:02 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-11-04  2:15 [PATCH] serial: meson: unregister the UART driver if port registration fails Wentao Liang
2026-11-04  2:15 ` Wentao Liang
2026-11-04  2:26 ` sashiko-bot
2026-11-04  7:02 ` Jiri Slaby [this message]
2026-11-04  7:02   ` Jiri Slaby
2026-11-04 10:49   ` Greg Kroah-Hartman
2026-11-04 10:49     ` Greg Kroah-Hartman
2026-11-04  8:45 ` Neil Armstrong
2026-11-04  8:45   ` Neil Armstrong

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