of just dropping the lock around the ip_output call. This used to cause
corrupted state tree walks for some call-paths.
In a second stage all callouts will be marked MPSAFE according to the
setting of mpsafenet.
Reported and tested by: Matthew Grooms <mgrooms at seton dot org>
MFC after: 3 days
X-MFC after: Marking callouts MPSAFE + 1 week