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From: Greg KH <gregkh@linuxfoundation.org>
To: Sherry Sun <sherry.sun@nxp.com>
Cc: jirislaby@kernel.org, linux-serial@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-imx@nxp.com
Subject: Re: [PATCH 1/2] tty: serial: fsl_lpuart: fix the potential bug of division or modulo by zero
Date: Mon, 26 Apr 2021 10:08:30 +0200	[thread overview]
Message-ID: <YIZ0/vRLASlUph6x@kroah.com> (raw)
In-Reply-To: <20210426074935.11131-2-sherry.sun@nxp.com>

On Mon, Apr 26, 2021 at 03:49:34PM +0800, Sherry Sun wrote:
> This issue is reported by Coverity Check.
> In lpuart32_console_get_options, division or modulo by zero may results
> in undefined behavior.
> 
> Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
> ---
>  drivers/tty/serial/fsl_lpuart.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
> index 794035041744..777d54b593f8 100644
> --- a/drivers/tty/serial/fsl_lpuart.c
> +++ b/drivers/tty/serial/fsl_lpuart.c
> @@ -2414,6 +2414,9 @@ lpuart32_console_get_options(struct lpuart_port *sport, int *baud,
>  
>  	bd = lpuart32_read(&sport->port, UARTBAUD);
>  	bd &= UARTBAUD_SBR_MASK;
> +	if (!bd)
> +		return;

How can this ever happen?

Not to say this is a bad check, but it feels like this can't really
happen in real life, what code patch could create this result?

And have you tested this on real hardware?

thanks,

greg k-h

  reply	other threads:[~2021-04-26  8:08 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-26  7:49 [PATCH 0/2] Fix two coverity issues in fsl_lpuart.c Sherry Sun
2021-04-26  7:49 ` [PATCH 1/2] tty: serial: fsl_lpuart: fix the potential bug of division or modulo by zero Sherry Sun
2021-04-26  8:08   ` Greg KH [this message]
2021-04-26 11:30     ` Sherry Sun
2021-04-26 11:34       ` Greg KH
2021-04-26 11:51         ` Sherry Sun
2021-04-26 12:23           ` Greg KH
2021-04-26 12:50             ` Sherry Sun
2021-04-26  7:49 ` [PATCH 2/2] tty: serial: fsl_lpuart: fix the potential bug of dereference null return value Sherry Sun
2021-04-26  8:09   ` Greg KH
2021-04-26 11:39     ` Sherry Sun
2021-04-26 11:57       ` Fabio Estevam
2021-04-26 12:09         ` Sherry Sun
2021-04-26 12:15           ` Fabio Estevam
2021-04-26 12:48             ` Sherry Sun
2021-04-26 12:22       ` Greg KH
2021-04-26 12:46         ` Sherry Sun

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