linux-kernel - Re: [PATCH] 8250-men-mcb: fix error checking when get_num

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Date:   Mon, 14 Oct 2019 08:55:15 +0200
From:   Michael Moese <mmoese@...e.de>
To:     Colin King <colin.king@...onical.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jslaby@...e.com>, linux-serial@...r.kernel.org
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] 8250-men-mcb: fix error checking when get_num_ports
 returns -ENODEV



On 14.10.19 00:00, Colin King wrote:
> From: Colin Ian King <colin.king@...onical.com>
> 
> The current checking for failure on the number of ports fails when
> -ENODEV is returned from the call to get_num_ports. Fix this by making
> num_ports and loop counter i signed rather than unsigned ints. Also
> add check for num_ports being less than zero to check for -ve error
> returns.
> 
> Addresses-Coverity: ("Unsigned compared against 0")
> Fixes: e2fea54e4592 ("8250-men-mcb: add support for 16z025 and 16z057")
> Signed-off-by: Colin Ian King <colin.king@...onical.com>

This looks more than reasonable to me, thanks.

Reviewed-by: Michael Moese <mmoese@...e.de>

> ---
>   drivers/tty/serial/8250/8250_men_mcb.c | 8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_men_mcb.c b/drivers/tty/serial/8250/8250_men_mcb.c
> index 02c5aff58a74..8df89e9cd254 100644
> --- a/drivers/tty/serial/8250/8250_men_mcb.c
> +++ b/drivers/tty/serial/8250/8250_men_mcb.c
> @@ -72,8 +72,8 @@ static int serial_8250_men_mcb_probe(struct mcb_device *mdev,
>   {
>   	struct serial_8250_men_mcb_data *data;
>   	struct resource *mem;
> -	unsigned int num_ports;
> -	unsigned int i;
> +	int num_ports;
> +	int i;
>   	void __iomem *membase;
>   
>   	mem = mcb_get_resource(mdev, IORESOURCE_MEM);
> @@ -88,7 +88,7 @@ static int serial_8250_men_mcb_probe(struct mcb_device *mdev,
>   	dev_dbg(&mdev->dev, "found a 16z%03u with %u ports\n",
>   		mdev->id, num_ports);
>   
> -	if (num_ports == 0 || num_ports > 4) {
> +	if (num_ports <= 0 || num_ports > 4) {
>   		dev_err(&mdev->dev, "unexpected number of ports: %u\n",
>   			num_ports);
>   		return -ENODEV;
> @@ -133,7 +133,7 @@ static int serial_8250_men_mcb_probe(struct mcb_device *mdev,
>   
>   static void serial_8250_men_mcb_remove(struct mcb_device *mdev)
>   {
> -	unsigned int num_ports, i;
> +	int num_ports, i;
>   	struct serial_8250_men_mcb_data *data = mcb_get_drvdata(mdev);
>   
>   	if (!data)
> 

-- 
Michael Moese <mmoese@...e.de>
QA Engineer
PGP Fingerprint: 4CCE 3896 F873 2CA5 2382  3C6F 6021 375C 8635 7E74

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