[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <40e4c6b1-e217-2926-a351-bf685a5b775f@linux.intel.com>
Date: Thu, 12 Oct 2023 16:10:27 +0300 (EEST)
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: Lino Sanfilippo <l.sanfilippo@...bus.com>
cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Jiri Slaby <jirislaby@...nel.org>, shawnguo@...nel.org,
s.hauer@...gutronix.de, mcoquelin.stm32@...il.com,
alexandre.torgue@...s.st.com, cniedermaier@...electronics.com,
LKML <linux-kernel@...r.kernel.org>,
linux-serial <linux-serial@...r.kernel.org>,
LinoSanfilippo@....de, Lukas Wunner <lukas@...ner.de>,
p.rosenberger@...bus.com, stable@...r.kernel.org
Subject: Re: [PATCH v3 3/6] serial: core: fix sanitizing check for RTS
settings
On Wed, 11 Oct 2023, Lino Sanfilippo wrote:
> Among other things uart_sanitize_serial_rs485() tests the sanity of the RTS
> settings in a RS485 configuration that has been passed by userspace.
> If RTS-on-send and RTS-after-send are both set or unset the configuration
> is adjusted and RTS-after-send is disabled and RTS-on-send enabled.
>
> This however makes only sense if both RTS modes are actually supported by
> the driver.
>
> With commit be2e2cb1d281 ("serial: Sanitize rs485_struct") the code does
> take the driver support into account but only checks if one of both RTS
> modes are supported. This may lead to the errorneous result of RTS-on-send
> being set even if only RTS-after-send is supported.
>
> Fix this by changing the implemented logic: First clear all unsupported
> flags in the RS485 configuration, then adjust an invalid RTS setting by
> taking into account which RTS mode is supported.
>
> Cc: stable@...r.kernel.org
> Fixes: be2e2cb1d281 ("serial: Sanitize rs485_struct")
> Signed-off-by: Lino Sanfilippo <l.sanfilippo@...bus.com>
> ---
> drivers/tty/serial/serial_core.c | 28 ++++++++++++++++++----------
> 1 file changed, 18 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
> index 697c36dc7ec8..f4feebf8200f 100644
> --- a/drivers/tty/serial/serial_core.c
> +++ b/drivers/tty/serial/serial_core.c
> @@ -1370,19 +1370,27 @@ static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs4
> return;
> }
>
> + rs485->flags &= supported_flags;
> +
> /* Pick sane settings if the user hasn't */
> - if ((supported_flags & (SER_RS485_RTS_ON_SEND|SER_RS485_RTS_AFTER_SEND)) &&
> - !(rs485->flags & SER_RS485_RTS_ON_SEND) ==
> + if (!(rs485->flags & SER_RS485_RTS_ON_SEND) ==
> !(rs485->flags & SER_RS485_RTS_AFTER_SEND)) {
> - dev_warn_ratelimited(port->dev,
> - "%s (%d): invalid RTS setting, using RTS_ON_SEND instead\n",
> - port->name, port->line);
> - rs485->flags |= SER_RS485_RTS_ON_SEND;
> - rs485->flags &= ~SER_RS485_RTS_AFTER_SEND;
> - supported_flags |= SER_RS485_RTS_ON_SEND|SER_RS485_RTS_AFTER_SEND;
> - }
> + if (supported_flags & SER_RS485_RTS_ON_SEND) {
> + rs485->flags |= SER_RS485_RTS_ON_SEND;
> + rs485->flags &= ~SER_RS485_RTS_AFTER_SEND;
>
> - rs485->flags &= supported_flags;
> + dev_warn_ratelimited(port->dev,
> + "%s (%d): invalid RTS setting, using RTS_ON_SEND instead\n",
> + port->name, port->line);
> + } else {
> + rs485->flags |= SER_RS485_RTS_AFTER_SEND;
> + rs485->flags &= ~SER_RS485_RTS_ON_SEND;
So if neither of the flags is supported, what will happen? You might want
add if after that else?
--
i.
Powered by blists - more mailing lists