trouble restarting a server

Hi all, I'm having some trouble restarting a long-running server. Basically,
pg_ctl can't kill any processes waiting on a notify interrupt. Here's what
happened after trying a "stop -m fast"

[root(at)vero ~]# ps axvw | grep post
3606 ? S 3:30 23 3260 41575 6644 0.1 /usr/bin/postgres -D
/postgres/db-8.2
4293 ? Ss 0:17 0 3260 40551 27004 0.6 postgres: writer
process
4294 ? Ss 0:00 0 3260 9363 1744 0.0 postgres: stats
collector process
14508 ? Ss 0:01 0 3260 41195 29356 0.7 postgres: me csdb
zim(48570) notify interrupt
20701 ? Ss 0:01 0 3260 41127 29384 0.7 postgres: others
csdb chef(45882) notify interrupt
31179 ? Ss 0:01 0 3260 41127 29428 0.7 postgres: others
csdb yfandes(33113) notify interrupt
7342 ? Ss 0:03 0 3260 41723 30584 0.7 postgres: others
csdb reed(54823) notify interrupt
7343 ? Ss 0:02 0 3260 41127 29396 0.7 postgres: others
csdb reed(54824) notify interrupt
7404 ? Ss 0:02 0 3260 41127 29392 0.7 postgres: others
csdb reed(54830) notify interrupt
29537 ? Ss 0:02 0 3260 41127 29404 0.7 postgres: others
csdb stupid(60028) notify interrupt
26671 pts/0 S+ 0:00 1 19 7976 1700 0.0 su postgres -c
/s/postgresql-8.2/bin/pg_ctl stop -m fast -D /scratch.1/postgres/csdb-8.2 -l
/dev/null
26672 pts/0 S+ 0:00 1 283 5556 1180 0.0 -csh -c
/usr/bin/pg_ctl stop -m fast -D /scratch.1/postgres/csdb- 8.2 -l /dev/null
26673 pts/0 S+ 0:00 0 23 6916 1440 0.0 /usr/bin/pg_ctl stop
-m fast -D /postgres/db-8.2 -l /dev/null
26713 ttyS0 S+ 0:00 0 71 5016 644 0.0 grep post

Any idea how postgres gets into this state, or how it can be resolved short
of a system reboot or a "stop -m immediate"? Thanks much.

Peter