netdev - RE: [PATCH net-next 6/8] net: ethernet: annapurna: add wol helpers to the Alpine driver

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Date:   Mon, 6 Feb 2017 11:35:49 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Sergei Shtylyov' <sergei.shtylyov@...entembedded.com>,
        Antoine Tenart <antoine.tenart@...e-electrons.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "davem@...emloft.net" <davem@...emloft.net>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>
CC:     "tsahee@...apurnalabs.com" <tsahee@...apurnalabs.com>,
        "rshitrit@...apurnalabs.com" <rshitrit@...apurnalabs.com>,
        "saeed@...apurnalabs.com" <saeed@...apurnalabs.com>,
        "barak@...apurnalabs.com" <barak@...apurnalabs.com>,
        "talz@...apurnalabs.com" <talz@...apurnalabs.com>,
        "thomas.petazzoni@...e-electrons.com" 
        <thomas.petazzoni@...e-electrons.com>,
        "arnd@...db.de" <arnd@...db.de>
Subject: RE: [PATCH net-next 6/8] net: ethernet: annapurna: add wol helpers
 to the Alpine driver

From: netdev-owner@...r.kernel.org [mailto:netdev-owner@...r.kernel.org] On Behalf Of Sergei Shtylyov
> Sent: 03 February 2017 18:22
> On 02/03/2017 09:12 PM, Antoine Tenart wrote:
> 
> > Implement the get_wol() and set_wol() helpers in the Annapurna Labs
> > Alpine Ethernet driver.
> > ---
> >  drivers/net/ethernet/annapurna/al_eth.c | 44 +++++++++++++++++++++++++++++++++
> >  1 file changed, 44 insertions(+)
> >
> > diff --git a/drivers/net/ethernet/annapurna/al_eth.c b/drivers/net/ethernet/annapurna/al_eth.c
> > index 8dd84f66b5d1..d06a75a49ce5 100644
> > --- a/drivers/net/ethernet/annapurna/al_eth.c
> > +++ b/drivers/net/ethernet/annapurna/al_eth.c
> > @@ -2519,10 +2519,54 @@ static u32 al_eth_get_rxfh_indir_size(struct net_device *netdev)
> >  	return AL_ETH_RX_RSS_TABLE_SIZE;
> >  }
> >
> > +static void al_eth_get_wol(struct net_device *netdev,
> > +			   struct ethtool_wolinfo *wol)
> > +{
> > +	struct al_eth_adapter *adapter = netdev_priv(netdev);
> > +	struct phy_device *phydev;
> > +
> > +	wol->wolopts = adapter->wol;
> > +
> > +	if ((adapter) && (adapter->phy_exist) && (adapter->mdio_bus)) {
> 
>     Now that's somewhat stupid looking... does the whole driver use this "style"?

Not only that, in one of the two functions it is followed by:

+	device_set_wakeup_enable(&adapter->pdev->dev, adapter->wol);

Which assumes that 'adapter' is not NULL.
Some verifiers will detect that as a possible NULL pointer dereference.

Pointers should only be checked for NULL if there are valid reasons
why they can be NULL in that code path.
Getting there with a NULL pointer dues to some race condition isn't one of them.

	David