net: phy: add locking to phy_read_mmd_indirect()/phy_write_mmd_indirect()
authorRussell King <rmk+kernel@arm.linux.org.uk>
Tue, 25 Aug 2015 08:49:47 +0000 (09:49 +0100)
committerDavid S. Miller <davem@davemloft.net>
Tue, 25 Aug 2015 23:30:46 +0000 (16:30 -0700)
commit05a7f582be961824d62a7f4a817f3783148b5f8a
treed43da7ed68308ae9b606d7ad681f5789c1956acd
parentbef0057b7ba881d5ae67eec876df7a26fe672a59
net: phy: add locking to phy_read_mmd_indirect()/phy_write_mmd_indirect()

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+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