[PATCH] serial: meson: unregister the UART driver if port registration fails

[PATCH] serial: meson: unregister the UART driver if port registration fails

[Wentao Liang]

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>
---
 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;
 }
-- 
2.34.1

Re: [PATCH] serial: meson: unregister the UART driver if port registration fails

[sashiko-bot]

> 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>

Sashiko has reviewed this patch and found no issues.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261104021501.1468500-1-vulab@iscas.ac.cn?part=1

Re: [PATCH] serial: meson: unregister the UART driver if port registration fails

[Jiri Slaby]

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

Re: [PATCH] serial: meson: unregister the UART driver if port registration fails

[Neil Armstrong]

On 11/4/26 03:15, 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>
> ---
>   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;
>   }

Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>

Thanks,
Neil

Re: [PATCH] serial: meson: unregister the UART driver if port registration fails

[Greg Kroah-Hartman]

On Wed, Nov 04, 2026 at 08:02:33AM +0100, Jiri Slaby wrote:
> 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>

Nope, this is a bot, I strongly recommend that everyone just add this
address to their email killfile as they never respond and spam out tons
of crap.

thanks,

greg k-h