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References: <20240110102102.61587-1-tudor.ambarus@linaro.org> <20240110102102.61587-11-tudor.ambarus@linaro.org>
In-Reply-To: <20240110102102.61587-11-tudor.ambarus@linaro.org>
From: Sam Protsenko <semen.protsenko@linaro.org>
Date: Tue, 16 Jan 2024 12:21:25 -0600
Message-ID: <CAPLW+4=YYdUSaaLcsdEyPswC4s6onxuSh24vSfw4xys=sPZG_Q@mail.gmail.com>
Subject: Re: [PATCH 10/18] tty: serial: samsung: make max_count unsigned int
To: Tudor Ambarus <tudor.ambarus@linaro.org>
Cc: krzysztof.kozlowski@linaro.org, alim.akhtar@samsung.com, 
	gregkh@linuxfoundation.org, jirislaby@kernel.org, 
	linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, 
	linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, 
	andre.draszik@linaro.org, peter.griffin@linaro.org, kernel-team@android.com, 
	willmcvicker@google.com
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On Wed, Jan 10, 2024 at 4:23=E2=80=AFAM Tudor Ambarus <tudor.ambarus@linaro=
org> wrote:
>
> ``max_count`` negative values are not used. Since ``port->fifosize``
> is an unsigned int, make ``max_count`` the same.
>
> Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
> ---
>  drivers/tty/serial/samsung_tty.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsun=
g_tty.c
> index 90c49197efc7..dbbe6b8e3ceb 100644
> --- a/drivers/tty/serial/samsung_tty.c
> +++ b/drivers/tty/serial/samsung_tty.c
> @@ -760,8 +760,8 @@ static irqreturn_t s3c24xx_serial_rx_chars_dma(void *=
dev_id)
>  static void s3c24xx_serial_rx_drain_fifo(struct s3c24xx_uart_port *ourpo=
rt)
>  {
>         struct uart_port *port =3D &ourport->port;
> +       unsigned int max_count =3D port->fifosize;

What if port->fifosize is 0? Then this code below:

    while (max_count-- > 0) {

would cause int overflow, if max_count is unsigned?

>         unsigned int fifocnt =3D 0;
> -       int max_count =3D port->fifosize;
>         u32 ufcon, ufstat, uerstat;
>         u8 ch, flag;
>
> --
> 2.43.0.472.g3155946c3a-goog
>
>