linux-kernel - Re: [PATCH v2 2/8] phy: mvebu-cp110-comphy: fix port check in ->xlate()

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Message-ID: <20181130190031.GH30658@n2100.armlinux.org.uk>
Date:   Fri, 30 Nov 2018 19:00:31 +0000
From:   Russell King - ARM Linux <linux@...linux.org.uk>
To:     Miquel Raynal <miquel.raynal@...tlin.com>
Cc:     Gregory Clement <gregory.clement@...tlin.com>,
        Jason Cooper <jason@...edaemon.net>,
        Andrew Lunn <andrew@...n.ch>,
        Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>,
        Kishon Vijay Abraham I <kishon@...com>,
        Mark Rutland <mark.rutland@....com>,
        devicetree@...r.kernel.org,
        Antoine Tenart <antoine.tenart@...tlin.com>,
        Grzegorz Jaszczyk <jaz@...ihalf.com>,
        linux-kernel@...r.kernel.org,
        Maxime Chevallier <maxime.chevallier@...tlin.com>,
        Nadav Haklai <nadavh@...vell.com>,
        Rob Herring <robh+dt@...nel.org>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        Marcin Wojtas <mw@...ihalf.com>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2 2/8] phy: mvebu-cp110-comphy: fix port check in
 ->xlate()

On Fri, Nov 30, 2018 at 03:47:37PM +0100, Miquel Raynal wrote:
> So far the PHY ->xlate() callback was checking if the port was
> "invalid" before continuing, meaning that the port has not been used
> yet. This check is not correct as there is no opposite call to
> ->xlate() once the PHY is released by the user and the port will
> remain "valid" after the first phy_get()/phy_put() calls. Hence, if
> this driver is built as a module, inserted, removed and inserted
> again, the PHY will appear busy and the second probe will fail.
> 
> To fix this, just drop the faulty check and instead verify that the
> port number is valid (ie. in the possible range).
> 
> Signed-off-by: Miquel Raynal <miquel.raynal@...tlin.com>
> ---
>  drivers/phy/marvell/phy-mvebu-cp110-comphy.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/phy/marvell/phy-mvebu-cp110-comphy.c b/drivers/phy/marvell/phy-mvebu-cp110-comphy.c
> index 31b9a1c18345..a40b876ff214 100644
> --- a/drivers/phy/marvell/phy-mvebu-cp110-comphy.c
> +++ b/drivers/phy/marvell/phy-mvebu-cp110-comphy.c
> @@ -567,9 +567,9 @@ static struct phy *mvebu_comphy_xlate(struct device *dev,
>  		return phy;
>  
>  	lane = phy_get_drvdata(phy);
> -	if (lane->port >= 0)
> -		return ERR_PTR(-EBUSY);
>  	lane->port = args->args[0];
> +	if (lane->port >= MVEBU_COMPHY_PORTS)
> +		return ERR_PTR(-EINVAL);

Shouldn't we validate args->args[0] before doing anything?

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
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