Vivek noted that many places call note_interrupt()
without desc->lock being held. Since note_interrupt()
which tries to unlock this lock to handle spurious
interrupts accodring to
http://kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=f72fa707604c015a6625e80f269506032d5430dc

Looking at note_interrupt() I found that desc->lock
IS required in this function but all the places that
call note_interrupt() lock it after the call. One
exception from this rule is __do_IRQ().

So I move spin_lock(&desc->lock); before calling
note_interrupt() in all places.

Signed-off-bt: Pavel Emelianov <xemul@openvz.org>