[PATCH 4.9 14/52] net: phy: micrel: fix crash when statistic requested for KSZ9031 phy

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Grygorii Strashko <grygorii.strashko@ti.com>

commit bfe72442578bb112626e476ffe1f276504d85b95 upstream.

Now the command:
	ethtool --phy-statistics eth0
will cause system crash with meassage "Unable to handle kernel NULL pointer
dereference at virtual address 00000010" from:

 (kszphy_get_stats) from [<c069f1d8>] (ethtool_get_phy_stats+0xd8/0x210)
 (ethtool_get_phy_stats) from [<c06a0738>] (dev_ethtool+0x5b8/0x228c)
 (dev_ethtool) from [<c06b5484>] (dev_ioctl+0x3fc/0x964)
 (dev_ioctl) from [<c0679f7c>] (sock_ioctl+0x170/0x2c0)
 (sock_ioctl) from [<c02419d4>] (do_vfs_ioctl+0xa8/0x95c)
 (do_vfs_ioctl) from [<c02422c4>] (SyS_ioctl+0x3c/0x64)
 (SyS_ioctl) from [<c0107d60>] (ret_fast_syscall+0x0/0x44)

The reason: phy_driver structure for KSZ9031 phy has no .probe() callback
defined. As result, struct phy_device *phydev->priv pointer will not be
initializes (null).
This issue will affect also following phys:
 KSZ8795, KSZ886X, KSZ8873MLL, KSZ9031, KSZ9021, KSZ8061, KS8737

Fix it by:
- adding .probe() = kszphy_probe() callback to KSZ9031, KSZ9021
phys. The kszphy_probe() can be re-used as it doesn't do any phy specific
settings.
- removing statistic callbacks from other phys (KSZ8795, KSZ886X,
KSZ8873MLL, KSZ8061, KS8737) as they doesn't have corresponding
statistic counters.

Fixes: 2b2427d06426 ("phy: micrel: Add ethtool statistics counters")
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Dan Rue <dan.rue@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/net/phy/micrel.c |   17 ++---------------
 1 file changed, 2 insertions(+), 15 deletions(-)

--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -801,9 +801,6 @@ static struct phy_driver ksphy_driver[]
 	.read_status	= genphy_read_status,
 	.ack_interrupt	= kszphy_ack_interrupt,
 	.config_intr	= kszphy_config_intr,
-	.get_sset_count = kszphy_get_sset_count,
-	.get_strings	= kszphy_get_strings,
-	.get_stats	= kszphy_get_stats,
 	.suspend	= genphy_suspend,
 	.resume		= genphy_resume,
 }, {
@@ -948,9 +945,6 @@ static struct phy_driver ksphy_driver[]
 	.read_status	= genphy_read_status,
 	.ack_interrupt	= kszphy_ack_interrupt,
 	.config_intr	= kszphy_config_intr,
-	.get_sset_count = kszphy_get_sset_count,
-	.get_strings	= kszphy_get_strings,
-	.get_stats	= kszphy_get_stats,
 	.suspend	= genphy_suspend,
 	.resume		= genphy_resume,
 }, {
@@ -960,6 +954,7 @@ static struct phy_driver ksphy_driver[]
 	.features	= (PHY_GBIT_FEATURES | SUPPORTED_Pause),
 	.flags		= PHY_HAS_MAGICANEG | PHY_HAS_INTERRUPT,
 	.driver_data	= &ksz9021_type,
+	.probe		= kszphy_probe,
 	.config_init	= ksz9021_config_init,
 	.config_aneg	= genphy_config_aneg,
 	.read_status	= genphy_read_status,
@@ -979,6 +974,7 @@ static struct phy_driver ksphy_driver[]
 	.features	= (PHY_GBIT_FEATURES | SUPPORTED_Pause),
 	.flags		= PHY_HAS_MAGICANEG | PHY_HAS_INTERRUPT,
 	.driver_data	= &ksz9021_type,
+	.probe		= kszphy_probe,
 	.config_init	= ksz9031_config_init,
 	.config_aneg	= genphy_config_aneg,
 	.read_status	= ksz9031_read_status,
@@ -998,9 +994,6 @@ static struct phy_driver ksphy_driver[]
 	.config_init	= kszphy_config_init,
 	.config_aneg	= ksz8873mll_config_aneg,
 	.read_status	= ksz8873mll_read_status,
-	.get_sset_count = kszphy_get_sset_count,
-	.get_strings	= kszphy_get_strings,
-	.get_stats	= kszphy_get_stats,
 	.suspend	= genphy_suspend,
 	.resume		= genphy_resume,
 }, {
@@ -1012,9 +1005,6 @@ static struct phy_driver ksphy_driver[]
 	.config_init	= kszphy_config_init,
 	.config_aneg	= genphy_config_aneg,
 	.read_status	= genphy_read_status,
-	.get_sset_count = kszphy_get_sset_count,
-	.get_strings	= kszphy_get_strings,
-	.get_stats	= kszphy_get_stats,
 	.suspend	= genphy_suspend,
 	.resume		= genphy_resume,
 }, {
@@ -1026,9 +1016,6 @@ static struct phy_driver ksphy_driver[]
 	.config_init	= kszphy_config_init,
 	.config_aneg	= ksz8873mll_config_aneg,
 	.read_status	= ksz8873mll_read_status,
-	.get_sset_count = kszphy_get_sset_count,
-	.get_strings	= kszphy_get_strings,
-	.get_stats	= kszphy_get_stats,
 	.suspend	= genphy_suspend,
 	.resume		= genphy_resume,
 } };