net: fec: fix spin_lock dead lock
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[ INFO: possible irq lock inversion dependency detected ]
3.8.0-rc5+ #82 Not tainted
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swapper/0/0 just changed the state of lock:
(&(&fep->hw_lock)->rlock){..-...}, at: [<8034e2f8>] fec_enet_start_xmit+0x48/0x 2cc
but this lock took another, SOFTIRQ-unsafe lock in the past:
(prepare_lock){+.+.+.}
and interrupts could create inverse lock ordering between them.
other info that might help us debug this:
Possible interrupt unsafe locking scenario:
CPU0 CPU1
---- ----
lock(prepare_lock);
local_irq_disable()
lock(&(&fep->hw_lock)->rlock);
lock(prepare_lock);
<Interrupt>
lock(&(&fep->hw_lock)->rlock);
*** DEADLOCK ***
Signed-off-by: Frank Li <Frank.Li@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 file changed