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Date:   Wed, 11 Jul 2018 20:15:48 +0000
From:   Dan Rue <dan.rue@linaro.org>
To:     Leonard Crestez <leonard.crestez@nxp.com>
Cc:     Florian Fainelli <f.fainelli@gmail.com>,
        Andrew Lunn <andrew@lunn.ch>,
        Grygorii Strashko <grygorii.strashko@ti.com>,
        open list <linux-kernel@vger.kernel.org>,
        linux- stable <stable@vger.kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <alexander.levin@microsoft.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Naresh Kamboju <naresh.kamboju@linaro.org>,
        chris.ruehl@gtsys.com.hk, Lars Persson <lars.persson@axis.com>
Subject: Re: [PATCH 4.9 181/310] net: phy: micrel: Restore led_mode and
 clk_sel on resume
Message-ID: <20180711201548.3rvad25yhcnr5h4e@linode.therub.org>
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On Thu, Apr 19, 2018 at 10:05:24PM +0300, Leonard Crestez wrote:
> On Thu, 2018-04-19 at 11:32 -0700, Florian Fainelli wrote:
> > +Others who reported the same problem
> > On 04/19/2018 11:24 AM, Naresh Kamboju wrote:
> > > On 19 April 2018 at 21:41, Leonard Crestez <leonard.crestez@nxp.com> wrote:
> > > > 
> > > > Looking at this dump I'm guessing that phydev->priv is NULL at the
> > > > start of kszphy_config_reset and this really shouldn't be happening.
> > > > 
> > > > The phydev->priv field is initialized by kszphy_probe but your
> > > > particular phy (KSZ9031) in linux-4.9.y does not seem to have .probe =
> > > > kszphy_probe assigned in the struct phy_driver ksphy_driver array.
> > > > 
> > > > In upstream this was added by commit bfe72442578b ("net: phy: micrel:
> > > > fix crash when statistic requested for KSZ9031 phy"). The message for
> > > > that patch claims to fix a kernel crash on this command:
> > > > 
> > > > ????ethtool --phy-statistics eth0
> > > > 
> > > > Looking at the code this issue should affect linux-4.9.y on your board.
> > > > Naresh: can you please check?
> > > After reverting the patch i have run this command and kernel oops
> > > showed up.
> > > ethtool --phy-statistics eth0
> > > 
> > > PC is at kszphy_get_stats+0x74/0xa8
> > > 
> > > ethtool --phy-statistics eth0 crashed on x15
> > >?
> > Chris proposed the following patch, which has not been formally
> > submitted yet:
> > 
> > Meanwhile, Greg seems to have reverted the offending patch, so we should
> > be good with 4.9.95.
> 
> I don't object to reverting my patch from linux-4.14.y but it seems all
> the affected hardware would also be affected by the crash from?ethtool
> --phy-statistics eth0. Adding?bfe72442578b to stable would be great
> because it fixes more than the patch in the title.
> 
> In the other thread there is a mention that "Micrel KSZ8795",
> "Micrel KSZ886X Switch", "Micrel KSZ8061", and "Micrel KS8737" might
> still have problems after?bfe72442578b. Is this because they have
> kszphy_config_init but not kszphy_probe? All versions of
> kszphy_config_init seem to check for a NULL priv.

To conclude this thread, bfe72442578b has been backported as of 4.9.112
and 'ethtool --phy-statistics eth0' no longer causes a NULL pointer
error.

Dan

> 
> --
> Regards,
> Leonard