Be more careful with sched_lock in the SIGINFO handler.  Specifically, do not hold sched_lock while calling ttyprintf().  If we are on a serial console, then ttyprintf() will end up getting the sio lock, resulting in a lock order violation.
Be more careful with sched_lock in the SIGINFO handler.  Specifically, do
not hold sched_lock while calling ttyprintf().  If we are on a serial
console, then ttyprintf() will end up getting the sio lock, resulting in
a lock order violation.

Noticed by:	des

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase