4.2-stable review patch. If anyone has any objections, please let me know.
------------------
From: "Maciej S. Szmigiero" <mail@xxxxxxxxxxxxxxxxxxxxx>
[ Upstream commit 42ea4457aea7aaeddf0c0b06724f297608f5e9d2 ]
If fec MDIO write method succeeds its return value comes from
call to pm_runtime_get_sync().
But pm_runtime_get_sync() can also return 1.
In case of Micrel KSZ9031 PHY this value will then
be returned along the call chain of phy_write() ->
ksz9031_extended_write() -> ksz9031_center_flp_timing() ->
ksz9031_config_init() -> phy_init_hw() -> phy_attach_direct() ->
phy_connect_direct().
Then phy_connect() will cast it into a pointer using ERR_PTR(),
which then fec_enet_mii_probe() will try to dereference
resulting in an oops.
Fix it by normalizing return value of pm_runtime_get_sync()
to be zero if positive in MDIO write method.
Fixes: 8fff755e9f8d ("net: fec: Ensure clocks are enabled while using mdio bus")
Signed-off-by: Maciej Szmigiero <mail@xxxxxxxxxxxxxxxxxxxxx>
Acked-by: Andrew Lunn <andrew@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/ethernet/freescale/fec_main.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -1811,11 +1811,13 @@ static int fec_enet_mdio_write(struct mi
struct fec_enet_private *fep = bus->priv;
struct device *dev = &fep->pdev->dev;
unsigned long time_left;
- int ret = 0;
+ int ret;
ret = pm_runtime_get_sync(dev);
if (ret < 0)
return ret;
+ else
+ ret = 0;
fep->mii_timeout = 0;
reinit_completion(&fep->mdio_done);
--
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