Re: [PATCH 4.9 181/310] net: phy: micrel: Restore led_mode and clk_sel on resume

[Naresh Kamboju]

On 19 April 2018 at 21:41, Leonard Crestez <leonard.crestez@xxxxxxx> wrote:
> On Thu, 2018-04-19 at 17:02 +0530, Naresh Kamboju wrote:
>> On 12 April 2018 at 00:05, Greg Kroah-Hartman
>> <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>> >
>> > 4.9-stable review patch.  If anyone has any objections, please let me know.
>> >
>> > ------------------
>> >
>> > From: Leonard Crestez <leonard.crestez@xxxxxxx>
>> >
>> > [ Upstream commit 79e498a9c7da0737829ff864aae44df434105676 ]
>> >
>> > These bits seem to be lost after a suspend/resume cycle so just set them
>> > again. Do this by splitting the handling of these bits into a function
>> > that is also called on resume.
>> >
>> > This patch fixes ethernet suspend/resume on imx6ul-14x14-evk boards.
>> >
>> > Signed-off-by: Leonard Crestez <leonard.crestez@xxxxxxx>
>> > Reviewed-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
>> > Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
>> > Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
>> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
>> > ---
>> >  drivers/net/phy/micrel.c |   42 ++++++++++++++++++++++++++++--------------
>> >  1 file changed, 28 insertions(+), 14 deletions(-)
>
>> arm32 x15 device booting 4.9 kernel shows kernel warning and
>> the network is not working on the device.
>>
>> Linux version 4.9.95-rc1 (buildslave@lkft-01) (gcc version 6.2.1 20161016
>>  (Linaro GCC 6.2-2016.11) ) #1 SMP Tue Apr 17 19:12:22 UTC 2018
>>
>> Boot log kernel crash log:
>> --------------------------
>> [   13.766589] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready
>> [   13.805441] net eth0: initializing cpsw version 1.15 (0)
>> [   13.930334] Unable to handle kernel NULL pointer dereference at
>> virtual address 00000008
>> [   13.982009] PC is at kszphy_config_reset+0x1c/0x150
>> [   13.986909] LR is at kszphy_resume+0x24/0x64
>> LAVA job id: https://lkft.validation.linaro.org/scheduler/job/187429#L3341
>
> 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
https://pastebin.com/8cGBMuxC

- Naresh