[root@pbx asterisk-1.6.0.1]# gdb asterisk /tmp/core.31442
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This GDB was configured as "i386-redhat-linux-gnu"...Using host libthread_db library "/lib/tls/libthread_db.so.1".

Core was generated by `/usr/sbin/asterisk -vvvg -c'.
Program terminated with signal 11, Segmentation fault.

#0  0x072d9426 in check_match (result=0x1257d08, item_fullname=0x0, item_ext=0x8f3a270 "106", pattern_ext=0x1257d18 "648", use_first_name=1)
    at app_directory.c:226
226                     digit = toupper(*text++);
(gdb) bt full
#0  0x072d9426 in check_match (result=0x1257d08, item_fullname=0x0, item_ext=0x8f3a270 "106", pattern_ext=0x1257d18 "648", use_first_name=1)
    at app_directory.c:226
        key = Variable "key" is not available.
(gdb) bt
#0  0x072d9426 in check_match (result=0x1257d08, item_fullname=0x0, item_ext=0x8f3a270 "106", pattern_ext=0x1257d18 "648", use_first_name=1)
    at app_directory.c:226
#1  0x072d9d97 in directory_exec (chan=0x8f26eb0, data=0x1259f50) at app_directory.c:581
#2  0x080e3ed6 in pbx_extension_helper (c=0x8f26eb0, con=0x0, context=0x8f27038 "bigincoming", exten=0x8f27088 "#", priority=1, label=0x0,
    callerid=0x8f8cab8 "2252141444", action=E_SPAWN, found=0x125c24c, combined_find_spawn=1)
    at /usr/src/asterisk-1.6/asterisk-1.6.0.1/include/asterisk/strings.h:47
#3  0x080ea3a2 in __ast_pbx_run (c=0x8f26eb0) at pbx.c:3604
#4  0x080ec8fe in pbx_thread (data=0x8f26eb0) at pbx.c:3954
#5  0x08126295 in dummy_start (data=0x125cb88) at utils.c:917
#6  0x004e73cc in start_thread () from /lib/tls/libpthread.so.0
#7  0x003f796e in clone () from /lib/tls/libc.so.6