trying to find the password-related segfault

gdb-run-password-segfault.txt

[~/src/SillyMUD]$ gdb src/dmserver 
GNU gdb 6.3.50-20050815 (Apple version gdb-1822) (Sun Aug  5 03:00:42 UTC 2012)
Copyright 2004 Free Software Foundation, Inc.
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This GDB was configured as "x86_64-apple-darwin"...Reading symbols for shared libraries .. done

(gdb) run
Starting program: /Users/jonm/src/SillyMUD/src/dmserver 
Reading symbols for shared libraries +..............bfd_mach_o_scan_read_symtab_symbol: symbol "_bzero" is unsupported 'indirect' reference: setting to undefined
bfd_mach_o_scan_read_symtab_symbol: symbol "_memccpy" is unsupported 'indirect' reference: setting to undefined
...
....warning: Could not find object file "/private/var/tmp/Libsyscall/Libsyscall-2422.115.14~1/Libsyscall.build/Libsyscall_dynamic.build/Objects-normal/x86_64/_libc_funcptr.o" - no debug information available for "_libc_funcptr.c".

warning: Could not find object file "/private/var/tmp/Libsyscall/Libsyscall-2422.115.14~1/Libsyscall.build/Libsyscall_dynamic.build/Objects-normal/x86_64/strlen.o" - no debug information available for "strlen.c".
...
warning: Could not find object file "/BinaryCache/libplatform/libplatform-24.90.1~2/Symbols/libucontext_normal.a(_setcontext.o)" - no debug information available for "_setcontext.s".

............ done
Mon Oct  5 06:04:30 2015 :: Running game on port 4000.
Mon Oct  5 06:04:30 2015 :: Using lib as data directory.
...
Performing boot-time init of Last Area (rooms 30000-999999).
Mon Oct  5 06:04:30 2015 :: Boot db -- DONE.
Mon Oct  5 06:04:30 2015 :: Entering game loop.
Mon Oct  5 06:04:56 2015 :: New connection from addr 127.0.0.1: 7: 7

Program received signal EXC_BAD_ACCESS, Could not access memory.
Reason: KERN_INVALID_ADDRESS at address: 0x00000000793aa7f0
0x00007fff8e9eb89b in strnlen ()
(gdb) bt
#0  0x00007fff8e9eb89b in strnlen ()
#1  0x00007fff5fbfda60 in ?? ()
#2  0x00007fff8e9fc813 in stpncpy ()
#3  0x00007fff8ea6a9cc in __strncpy_chk ()
#4  0x0000000100065cc6 in nanny (d=0x10100ee00, arg=0x7fff5fbff080 "blahblah") at interpreter.c:1335
#5  0x0000000100002f09 in game_loop (s=0) at comm.c:423
#6  0x00000001000020f5 in run_the_game (port=4000) at comm.c:243
#7  0x0000000100002033 in main (argc=1, argv=0x7fff5fbff400) at comm.c:205
(gdb)