linux-kernel - Re: [PATCH 1/3] net: phy: Check phy

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Message-ID: <20180607165227.GD25513@lunn.ch>
Date:   Thu, 7 Jun 2018 18:52:27 +0200
From:   Andrew Lunn <andrew@...n.ch>
To:     Brandon Maier <brandon.maier@...kwellcollins.com>
Cc:     netdev@...r.kernel.org, f.fainelli@...il.com, davem@...emloft.net,
        michal.simek@...inx.com, clayton.shotwell@...kwellcollins.com,
        kristopher.cory@...kwellcollins.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] net: phy: Check phy_driver ready before accessing

On Thu, Jun 07, 2018 at 10:53:46AM -0500, Brandon Maier wrote:
> Since a phy_device is added to the global mdio_bus list during
> phy_device_register(), but a phy_device's phy_driver doesn't get
> attached until phy_probe(). It's possible of_phy_find_device() in
> xgmiitorgmii will return a valid phy with a NULL phy_driver. Leading to
> a NULL pointer access during the memcpy().

I'm sure there are more issues like this in the code.  e.g. there is
no attempt made to hold a reference to the child phy. So it could be
unbound. priv->phy_drv->read_status(phydev) is then going to do bad
things.

Reviewed-by: Andrew Lunn <andrew@...n.ch>

    Andrew