Hey-
        Eric was using dropwatch recently and reported a few bugs to me that he
had noted.  This short series should fix them all up.

Change Notes:
V2)
	renamed trace_state_lock to trace_state_mutex
	cleaned up rcu write side access to use rcu_dereference_protected
	handled some NULL allocation failure cases


Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: Eric Dumazet <redacted>
CC: David Miller <davem@davemloft.net>