[PATCH net-next v2 1/3] net: phy: xgmiitorgmii: Check phy_driver ready before accessing

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().

Fixes this Oops:

Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = c0004000
[00000000] *pgd=00000000
Internal error: Oops: 5 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.14.40 #1
Hardware name: Xilinx Zynq Platform
task: ce4c8d00 task.stack: ce4ca000
PC is at memcpy+0x48/0x330
LR is at xgmiitorgmii_probe+0x90/0xe8
pc : [<c074bc68>]    lr : [<c0529548>]    psr: 20000013
sp : ce4cbb54  ip : 00000000  fp : ce4cbb8c
r10: 00000000  r9 : 00000000  r8 : c0c49178
r7 : 00000000  r6 : cdc14718  r5 : ce762800  r4 : cdc14710
r3 : 00000000  r2 : 00000054  r1 : 00000000  r0 : cdc14718
Flags: nzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
Control: 18c5387d  Table: 0000404a  DAC: 00000051
Process swapper/0 (pid: 1, stack limit = 0xce4ca210)
...
[<c074bc68>] (memcpy) from [<c0529548>] (xgmiitorgmii_probe+0x90/0xe8)
[<c0529548>] (xgmiitorgmii_probe) from [<c0526a94>] (mdio_probe+0x28/0x34)
[<c0526a94>] (mdio_probe) from [<c04db98c>] (driver_probe_device+0x254/0x414)
[<c04db98c>] (driver_probe_device) from [<c04dbd58>] (__device_attach_driver+0xac/0x10c)
[<c04dbd58>] (__device_attach_driver) from [<c04d96f4>] (bus_for_each_drv+0x84/0xc8)
[<c04d96f4>] (bus_for_each_drv) from [<c04db5bc>] (__device_attach+0xd0/0x134)
[<c04db5bc>] (__device_attach) from [<c04dbdd4>] (device_initial_probe+0x1c/0x20)
[<c04dbdd4>] (device_initial_probe) from [<c04da8fc>] (bus_probe_device+0x98/0xa0)
[<c04da8fc>] (bus_probe_device) from [<c04d8660>] (device_add+0x43c/0x5d0)
[<c04d8660>] (device_add) from [<c0526cb8>] (mdio_device_register+0x34/0x80)
[<c0526cb8>] (mdio_device_register) from [<c0580b48>] (of_mdiobus_register+0x170/0x30c)
[<c0580b48>] (of_mdiobus_register) from [<c05349c4>] (macb_probe+0x710/0xc00)
[<c05349c4>] (macb_probe) from [<c04dd700>] (platform_drv_probe+0x44/0x80)
[<c04dd700>] (platform_drv_probe) from [<c04db98c>] (driver_probe_device+0x254/0x414)
[<c04db98c>] (driver_probe_device) from [<c04dbc58>] (__driver_attach+0x10c/0x118)
[<c04dbc58>] (__driver_attach) from [<c04d9600>] (bus_for_each_dev+0x8c/0xd0)
[<c04d9600>] (bus_for_each_dev) from [<c04db1fc>] (driver_attach+0x2c/0x30)
[<c04db1fc>] (driver_attach) from [<c04daa98>] (bus_add_driver+0x50/0x260)
[<c04daa98>] (bus_add_driver) from [<c04dc440>] (driver_register+0x88/0x108)
[<c04dc440>] (driver_register) from [<c04dd6b4>] (__platform_driver_register+0x50/0x58)
[<c04dd6b4>] (__platform_driver_register) from [<c0b31248>] (macb_driver_init+0x24/0x28)
[<c0b31248>] (macb_driver_init) from [<c010203c>] (do_one_initcall+0x60/0x1a4)
[<c010203c>] (do_one_initcall) from [<c0b00f78>] (kernel_init_freeable+0x15c/0x1f8)
[<c0b00f78>] (kernel_init_freeable) from [<c0763d10>] (kernel_init+0x18/0x124)
[<c0763d10>] (kernel_init) from [<c0112d74>] (ret_from_fork+0x14/0x20)
Code: ba000002 f5d1f03c f5d1f05c f5d1f07c (e8b151f8)
---[ end trace 3e4ec21905820a1f ]---

Signed-off-by: Brandon Maier <redacted>
---
v2:
- Add Oops to commit message

v1: https://marc.info/?l=linux-netdev&m=152838762210538&w=2

 drivers/net/phy/xilinx_gmii2rgmii.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/phy/xilinx_gmii2rgmii.c b/drivers/net/phy/xilinx_gmii2rgmii.c
index 2e5150b0b8d5..04c8bec1c4c1 100644
--- a/drivers/net/phy/xilinx_gmii2rgmii.c
+++ b/drivers/net/phy/xilinx_gmii2rgmii.c

@@ -81,6 +81,11 @@ static int xgmiitorgmii_probe(struct mdio_device *mdiodev)
 		return -EPROBE_DEFER;
 	}
 
+	if (!priv->phy_dev->drv) {
+		dev_info(dev, "Attached phy not ready\n");
+		return -EPROBE_DEFER;
+	}
+
 	priv->addr = mdiodev->addr;
 	priv->phy_drv = priv->phy_dev->drv;
 	memcpy(&priv->conv_phy_drv, priv->phy_dev->drv,

-- 
2.17.1

The xgmiitorgmii is using the mii_bus of the device it's attached to,
instead of the bus it was given during probe.

Signed-off-by: Brandon Maier <redacted>
---
v2:
- Fix trivial typo in commit message

v1: https://marc.info/?l=linux-netdev&m=152838761310537&w=2

 drivers/net/phy/xilinx_gmii2rgmii.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/net/phy/xilinx_gmii2rgmii.c b/drivers/net/phy/xilinx_gmii2rgmii.c
index 04c8bec1c4c1..d6f8b64cddbe 100644
--- a/drivers/net/phy/xilinx_gmii2rgmii.c
+++ b/drivers/net/phy/xilinx_gmii2rgmii.c

@@ -33,17 +33,19 @@ struct gmii2rgmii {
 	struct phy_device *phy_dev;
 	struct phy_driver *phy_drv;
 	struct phy_driver conv_phy_drv;
-	int addr;
+	struct mdio_device *mdio;
 };
 
 static int xgmiitorgmii_read_status(struct phy_device *phydev)
 {
 	struct gmii2rgmii *priv = phydev->priv;
+	struct mii_bus *bus = priv->mdio->bus;
+	int addr = priv->mdio->addr;
 	u16 val = 0;
 
 	priv->phy_drv->read_status(phydev);
 
-	val = mdiobus_read(phydev->mdio.bus, priv->addr, XILINX_GMII2RGMII_REG);
+	val = mdiobus_read(bus, addr, XILINX_GMII2RGMII_REG);
 	val &= ~XILINX_GMII2RGMII_SPEED_MASK;
 
 	if (phydev->speed == SPEED_1000)

@@ -53,7 +55,7 @@ static int xgmiitorgmii_read_status(struct phy_device *phydev)
 	else
 		val |= BMCR_SPEED10;
 
-	mdiobus_write(phydev->mdio.bus, priv->addr, XILINX_GMII2RGMII_REG, val);
+	mdiobus_write(bus, addr, XILINX_GMII2RGMII_REG, val);
 
 	return 0;
 }

@@ -86,7 +88,7 @@ static int xgmiitorgmii_probe(struct mdio_device *mdiodev)
 		return -EPROBE_DEFER;
 	}
 
-	priv->addr = mdiodev->addr;
+	priv->mdio = mdiodev;
 	priv->phy_drv = priv->phy_dev->drv;
 	memcpy(&priv->conv_phy_drv, priv->phy_dev->drv,
 	       sizeof(struct phy_driver));

-- 
2.17.1

On Tue, Jun 26, 2018 at 12:50:49PM -0500, Brandon Maier wrote:

The xgmiitorgmii is using the mii_bus of the device it's attached to,
instead of the bus it was given during probe.

Signed-off-by: Brandon Maier <redacted>

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

    Andrew

From: Brandon Maier <redacted>
Date: Tue, 26 Jun 2018 12:50:49 -0500

The xgmiitorgmii is using the mii_bus of the device it's attached to,
instead of the bus it was given during probe.

Signed-off-by: Brandon Maier <redacted>

Applied.

We're ignoring the result of the attached phy device's read_status().
Return it so we can detect errors.

Signed-off-by: Brandon Maier <redacted>
---
v2:
- No change

v1: https://marc.info/?l=linux-netdev&m=152838766410559&w=2

 drivers/net/phy/xilinx_gmii2rgmii.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/xilinx_gmii2rgmii.c b/drivers/net/phy/xilinx_gmii2rgmii.c
index d6f8b64cddbe..74a8782313cf 100644
--- a/drivers/net/phy/xilinx_gmii2rgmii.c
+++ b/drivers/net/phy/xilinx_gmii2rgmii.c

@@ -42,8 +42,11 @@ static int xgmiitorgmii_read_status(struct phy_device *phydev)
 	struct mii_bus *bus = priv->mdio->bus;
 	int addr = priv->mdio->addr;
 	u16 val = 0;
+	int err;
 
-	priv->phy_drv->read_status(phydev);
+	err = priv->phy_drv->read_status(phydev);
+	if (err < 0)
+		return err;
 
 	val = mdiobus_read(bus, addr, XILINX_GMII2RGMII_REG);
 	val &= ~XILINX_GMII2RGMII_SPEED_MASK;

-- 
2.17.1

On Tue, Jun 26, 2018 at 12:50:50PM -0500, Brandon Maier wrote:

We're ignoring the result of the attached phy device's read_status().
Return it so we can detect errors.

Signed-off-by: Brandon Maier <redacted>

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

    Andrew

From: Brandon Maier <redacted>
Date: Tue, 26 Jun 2018 12:50:50 -0500

We're ignoring the result of the attached phy device's read_status().
Return it so we can detect errors.

Signed-off-by: Brandon Maier <redacted>

Applied.

On Tue, Jun 26, 2018 at 12:50:48PM -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().

Signed-off-by: Brandon Maier <redacted>

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

    Andrew

On 06/26/2018 10:50 AM, 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().

Fixes this Oops:

Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = c0004000
[00000000] *pgd=00000000
Internal error: Oops: 5 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.14.40 #1
Hardware name: Xilinx Zynq Platform
task: ce4c8d00 task.stack: ce4ca000
PC is at memcpy+0x48/0x330
LR is at xgmiitorgmii_probe+0x90/0xe8
pc : [<c074bc68>]    lr : [<c0529548>]    psr: 20000013
sp : ce4cbb54  ip : 00000000  fp : ce4cbb8c
r10: 00000000  r9 : 00000000  r8 : c0c49178
r7 : 00000000  r6 : cdc14718  r5 : ce762800  r4 : cdc14710
r3 : 00000000  r2 : 00000054  r1 : 00000000  r0 : cdc14718
Flags: nzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
Control: 18c5387d  Table: 0000404a  DAC: 00000051
Process swapper/0 (pid: 1, stack limit = 0xce4ca210)
...
[<c074bc68>] (memcpy) from [<c0529548>] (xgmiitorgmii_probe+0x90/0xe8)
[<c0529548>] (xgmiitorgmii_probe) from [<c0526a94>] (mdio_probe+0x28/0x34)
[<c0526a94>] (mdio_probe) from [<c04db98c>] (driver_probe_device+0x254/0x414)
[<c04db98c>] (driver_probe_device) from [<c04dbd58>] (__device_attach_driver+0xac/0x10c)
[<c04dbd58>] (__device_attach_driver) from [<c04d96f4>] (bus_for_each_drv+0x84/0xc8)
[<c04d96f4>] (bus_for_each_drv) from [<c04db5bc>] (__device_attach+0xd0/0x134)
[<c04db5bc>] (__device_attach) from [<c04dbdd4>] (device_initial_probe+0x1c/0x20)
[<c04dbdd4>] (device_initial_probe) from [<c04da8fc>] (bus_probe_device+0x98/0xa0)
[<c04da8fc>] (bus_probe_device) from [<c04d8660>] (device_add+0x43c/0x5d0)
[<c04d8660>] (device_add) from [<c0526cb8>] (mdio_device_register+0x34/0x80)
[<c0526cb8>] (mdio_device_register) from [<c0580b48>] (of_mdiobus_register+0x170/0x30c)
[<c0580b48>] (of_mdiobus_register) from [<c05349c4>] (macb_probe+0x710/0xc00)
[<c05349c4>] (macb_probe) from [<c04dd700>] (platform_drv_probe+0x44/0x80)
[<c04dd700>] (platform_drv_probe) from [<c04db98c>] (driver_probe_device+0x254/0x414)
[<c04db98c>] (driver_probe_device) from [<c04dbc58>] (__driver_attach+0x10c/0x118)
[<c04dbc58>] (__driver_attach) from [<c04d9600>] (bus_for_each_dev+0x8c/0xd0)
[<c04d9600>] (bus_for_each_dev) from [<c04db1fc>] (driver_attach+0x2c/0x30)
[<c04db1fc>] (driver_attach) from [<c04daa98>] (bus_add_driver+0x50/0x260)
[<c04daa98>] (bus_add_driver) from [<c04dc440>] (driver_register+0x88/0x108)
[<c04dc440>] (driver_register) from [<c04dd6b4>] (__platform_driver_register+0x50/0x58)
[<c04dd6b4>] (__platform_driver_register) from [<c0b31248>] (macb_driver_init+0x24/0x28)
[<c0b31248>] (macb_driver_init) from [<c010203c>] (do_one_initcall+0x60/0x1a4)
[<c010203c>] (do_one_initcall) from [<c0b00f78>] (kernel_init_freeable+0x15c/0x1f8)
[<c0b00f78>] (kernel_init_freeable) from [<c0763d10>] (kernel_init+0x18/0x124)
[<c0763d10>] (kernel_init) from [<c0112d74>] (ret_from_fork+0x14/0x20)
Code: ba000002 f5d1f03c f5d1f05c f5d1f07c (e8b151f8)
---[ end trace 3e4ec21905820a1f ]---

Signed-off-by: Brandon Maier <redacted>

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian

From: Brandon Maier <redacted>
Date: Tue, 26 Jun 2018 12:50:48 -0500

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().

Fixes this Oops:

 ...

Signed-off-by: Brandon Maier <redacted>

Applied.