netdev - Re: [PATCH 2/2][next] net: usb: asix: ax88772: net: Fix less than zero comparison of a u16

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Message-ID: <20210608181129.7mnuba6dcaemslul@pengutronix.de>
Date:   Tue, 8 Jun 2021 20:11:29 +0200
From:   Oleksij Rempel <o.rempel@...gutronix.de>
To:     Colin King <colin.king@...onical.com>
Cc:     "David S . Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Oleksij Rempel <linux@...pel-privat.de>,
        linux-usb@...r.kernel.org, netdev@...r.kernel.org,
        kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2][next] net: usb: asix: ax88772: net: Fix less than
 zero comparison of a u16

On Tue, Jun 08, 2021 at 04:22:49PM +0100, Colin King wrote:
> From: Colin Ian King <colin.king@...onical.com>
> 
> The comparison of the u16 priv->phy_addr < 0 is always false because
> phy_addr is unsigned. Fix this by assigning the return from the call
> to function asix_read_phy_addr to int ret and using this for the
> less than zero error check comparison.
> 
> Addresses-Coverity: ("Unsigned compared against 0")
> Fixes: 7e88b11a862a ("net: usb: asix: refactor asix_read_phy_addr() and handle errors on return")

Here is wrong Fixes tag. This assignment was bogus before this patch.

> Signed-off-by: Colin Ian King <colin.king@...onical.com>
> ---
>  drivers/net/usb/ax88172a.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/usb/ax88172a.c b/drivers/net/usb/ax88172a.c
> index 2e2081346740..e24773bb9398 100644
> --- a/drivers/net/usb/ax88172a.c
> +++ b/drivers/net/usb/ax88172a.c
> @@ -205,7 +205,8 @@ static int ax88172a_bind(struct usbnet *dev, struct usb_interface *intf)
>  		goto free;
>  	}
>  
> -	priv->phy_addr = asix_read_phy_addr(dev, priv->use_embdphy);
> +	ret = asix_read_phy_addr(dev, priv->use_embdphy);
> +	priv->phy_addr = ret;

Ah.. it is same bug in different color :)
You probably wonted to do:
	if (ret < 0)
		goto free;

	priv->phy_addr = ret;

>  	if (priv->phy_addr < 0) {
>  		ret = priv->phy_addr;
>  		goto free;
> -- 
> 2.31.1
> 
> 

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