3.19.8-ckt7 -stable review patch. If anyone has any objections, please let me
know.
------------------
From: Russell King <rmk+ker...@arm.linux.org.uk>
commit 05a7f582be961824d62a7f4a817f3783148b5f8a upstream.
The phy layer is missing locking for the above two functions - it
has been observed that two threads (userspace and the phy worker
thread) can race, entering the bus ->write or ->read functions
simultaneously.
This causes the FEC driver to initialise a completion while another
thread is waiting on it or while the interrupt is calling complete()
on it, which causes spinlock unlock-without-lock, spinlock lockups,
and completion timeouts.
Fixes: a59a4d192 ("phy: add the EEE support and the way to access to the MMD
registers.")
Fixes: 0c1d77dfb ("net: libphy: Add phy specific function to access mmd phy
registers")
Signed-off-by: Russell King <rmk+ker...@arm.linux.org.uk>
Acked-by: Florian Fainelli <f.faine...@gmail.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Kamal Mostafa <ka...@canonical.com>
---
drivers/net/phy/phy.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index 91d6d03..15a7387 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -993,10 +993,14 @@ int phy_read_mmd_indirect(struct phy_device *phydev, int
prtad,
int value = -1;
if (phydrv->read_mmd_indirect == NULL) {
- mmd_phy_indirect(phydev->bus, prtad, devad, addr);
+ struct mii_bus *bus = phydev->bus;
+
+ mutex_lock(&bus->mdio_lock);
+ mmd_phy_indirect(bus, prtad, devad, addr);
/* Read the content of the MMD's selected register */
- value = phydev->bus->read(phydev->bus, addr, MII_MMD_DATA);
+ value = bus->read(bus, addr, MII_MMD_DATA);
+ mutex_unlock(&bus->mdio_lock);
} else {
value = phydrv->read_mmd_indirect(phydev, prtad, devad, addr);
}
@@ -1026,10 +1030,14 @@ void phy_write_mmd_indirect(struct phy_device *phydev,
int prtad,
struct phy_driver *phydrv = phydev->drv;
if (phydrv->write_mmd_indirect == NULL) {
- mmd_phy_indirect(phydev->bus, prtad, devad, addr);
+ struct mii_bus *bus = phydev->bus;
+
+ mutex_lock(&bus->mdio_lock);
+ mmd_phy_indirect(bus, prtad, devad, addr);
/* Write the data into MMD's selected register */
- phydev->bus->write(phydev->bus, addr, MII_MMD_DATA, data);
+ bus->write(bus, addr, MII_MMD_DATA, data);
+ mutex_unlock(&bus->mdio_lock);
} else {
phydrv->write_mmd_indirect(phydev, prtad, devad, addr, data);
}
--
1.9.1
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