On HP-UX 10.20, bash coredumps when I <CTRL>-<R/L Arrow>

[brianm]

Configuration Information [Automatically generated, do not change]:
Machine: hppa1.1
OS: hpux10.20
Compiler: gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='hppa1.1' 
-DCONF_OSTYPE='hpux10.20' -DCONF_MACHTYPE='hppa1.1-hp-hpux10.20' 
-DCONF_VENDOR='hp' -DSHELL -DHAVE_CONFIG_H -DHPUX  -I.  -I. -I./include -I./lib 
 -g -O2
uname output: HP-UX ws3-nhdr B.10.20 A 9000/770 2001219784 two-user license
Machine Type: hppa1.1-hp-hpux10.20

Bash Version: 2.05b
Patch Level: 0
Release Status: release

Description:
  This bug (?) is repeatable. If I fire up bash, type a few simple commands 
(ls, more, echo), then 
  press the up arrow key (command line history recall) and then proceed to do a 
little command
  line editing, using the <CTRL>-<Right Arrow> or <CTRL>-<Left Arrow> to skip 
across words, the program
  dumps core.
   
  Here is an example of the output:

  ws3:brianm:5$ ls -lrt
  Pid 3384 received a SIGSEGV for stack growth failure.
  Possible causes: insufficient memory or swap space,
  or stack size exceeded maxssiz.
  Memory fault(coredump)

  I tried building with --without-gnu-malloc set but that didn't have any 
impact.

Repeat-By:
  See above

Fix:
        [Description of how to fix the problem.  If you don't know a
        fix for the problem, don't include this section.]