9.1.1 crash

The following are the relevant log entries from a recent crash of v9.1.1
running on an older RHEL Linux box. This is the first crash we've
experienced in a lot of years of running Pg. Any assistance in how to
determine what might have caused this is welcome.

--

2012-02-10 13:55:59 CST [15949]: [37-1] @ LOG: 00000: server process (PID
32670) was terminated by signal 11: Segmentation fault
2012-02-10 13:55:59 CST [15949]: [38-1] @ LOCATION: LogChildExit,
postmaster.c:2881
2012-02-10 13:55:59 CST [15949]: [39-1] @ LOG: 00000: terminating any
other active server processes
2012-02-10 13:55:59 CST [15949]: [40-1] @ LOCATION: HandleChildCrash,
postmaster.c:2695
2012-02-10 13:55:59 CST [15949]: [41-1] @ LOG: 00000: all server processes
terminated; reinitializing
2012-02-10 13:55:59 CST [15949]: [42-1] @ LOCATION:
PostmasterStateMachine, postmaster.c:3116
2012-02-10 13:56:00 CST [3303]: [1-1] @ LOG: 00000: database system was
interrupted; last known up at 2012-02-10 13:54:18 CST
2012-02-10 13:56:00 CST [3303]: [2-1] @ LOCATION: StartupXLOG, xlog.c:6046
2012-02-10 13:56:00 CST [3303]: [3-1] @ LOG: 00000: database system was
not properly shut down; automatic recovery in progress
2012-02-10 13:56:00 CST [3303]: [4-1] @ LOCATION: StartupXLOG, xlog.c:6299
2012-02-10 13:56:00 CST [3303]: [5-1] @ LOG: 00000: consistent recovery
state reached at F/FC9C7588
2012-02-10 13:56:00 CST [3303]: [6-1] @ LOCATION:
CheckRecoveryConsistency, xlog.c:6958
2012-02-10 13:56:00 CST [3303]: [7-1] @ LOG: 00000: redo starts at
F/FC9A5BA8
2012-02-10 13:56:00 CST [3303]: [8-1] @ LOCATION: StartupXLOG, xlog.c:6506
2012-02-10 13:56:00 CST [3303]: [9-1] @ LOG: 00000: record with zero
length at F/FCC716F0
2012-02-10 13:56:00 CST [3303]: [10-1] @ LOCATION: ReadRecord, xlog.c:3829
2012-02-10 13:56:00 CST [3303]: [11-1] @ LOG: 00000: redo done at
F/FCC716B4
2012-02-10 13:56:00 CST [3303]: [12-1] @ LOCATION: StartupXLOG, xlog.c:6621
2012-02-10 13:56:00 CST [3303]: [13-1] @ LOG: 00000: last completed
transaction was at log time 2012-02-10 13:55:59.452228-06
2012-02-10 13:56:00 CST [3303]: [14-1] @ LOCATION: StartupXLOG, xlog.c:6626
2012-02-10 13:56:02 CST [3319]: [1-1] @ LOG: 00000: autovacuum launcher
started
2012-02-10 13:56:02 CST [3319]: [2-1] @ LOCATION: AutoVacLauncherMain,
autovacuum.c:404
2012-02-10 13:56:02 CST [15949]: [43-1] @ LOG: 00000: database system is
ready to accept connections
2012-02-10 13:56:02 CST [15949]: [44-1] @ LOCATION: reaper,
postmaster.c:2435