Curious problem w/ 5.2-RELEASE su

[Brian Ledbetter]

I have two systems which I recently upgraded from src to
5.2-RELEASE.  (Both systems were upgraded from the same
/usr/src tree)  Everything seemed to be working fine until
a little while ago this morning, when I started having this
problem with /usr/bin/su:

$ su -
su in free(): error: chunk is already free
Abort trap (core dumped)
$ sudo sh
$ id
uid=0(root) gid=0(wheel) groups=0(wheel), 2(kmem), 3(sys),
4(tty), 5(operator), 20(staff), 31(guest)
$ su - 
su in free(): error: chunk is already free
Abort trap (core dumped)

Does anyone have any idea what would be causing this?  The
MD5 hash of /usr/bin/su and all linked libraries are identical
between the two systems, but /usr/sbin/su works just fine on
the other host.  dmesg reports nothing unusual on system startup.
What can I do to fix this?

Thanks in advance!

-- 
Brian C. Ledbetter <brian at shadowcom.net>
http://www.shadowcom.net/brian/