net: phy: add locking to phy_read_mmd_indirect()/phy_write_mmd_indirect() (05a7f582) · Commits · 戴 / test

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: ("phy: add the EEE support and the way to access to the MMD registers.") Fixes: ("net: libphy: Add phy specific function to access mmd phy registers") Signed-off-by:

Russell King <rmk+kernel@arm.linux.org.uk> Acked-by:

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

David S. Miller <davem@davemloft.net>

drivers/net/phy/phy.c

+12 −4

Original line number	Diff line number	Diff line
		@@ -1038,10 +1038,14 @@ 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);
		}
		@@ -1071,10 +1075,14 @@ 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);
		}

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