Is there a bug in SysV that permits a process to loose it's controlling tty

[Mike Wescott]

We have seen occasions where a getty gets spawned by init (this is System V, now)
and it opens up the line OK (a directly connected terminal) but getty, login, and
the resulting shell have lost their "controlling tty", i.e. the interrupt and quit
signals are ignored from the keyboard and "/dev/tty" cannot be opened.

/etc/crash shows that u.u_ttyp is null.

What sequence of events can result in this?  Any known bugs of this kind?

-- 
	-Mike Wescott
	 ncrcae!wescott