......
Loaded symbols for /usr/lib/asterisk/modules/app_mixmonitor.so
Reading symbols from /usr/lib/asterisk/modules/app_waitforsilence.so...done.
Loaded symbols for /usr/lib/asterisk/modules/app_waitforsilence.so
Reading symbols from /usr/lib/asterisk/modules/app_sendtext.so...done.
Loaded symbols for /usr/lib/asterisk/modules/app_sendtext.so
#0  0x0051f4cf in vfprintf () from /lib/libc.so.6
(gdb) bt
#0  0x0051f4cf in vfprintf () from /lib/libc.so.6
#1  0x005385a6 in vsprintf () from /lib/libc.so.6
#2  0x080ca03a in __ast_string_field_index_build (pool=0xb7806e54,
    fields=0xb771c008, num_fields=38, index=35, format=0x2aa30d "<sip:%s%s%s>")
    at utils.c:1010
#3  0x00296376 in handle_request_register (p=0xb7806da0, req=0xb7ca6b60, debug=Variable "debug" is not available.

) at chan_sip.c:4726
#4  0x002a797a in handle_request (p=0xb7806da0, req=0xb7ca6b60,
    sin=0xb7ca7e90, recount=0xb7ca7ea0, nounlock=0xb7ca7ea4)
    at chan_sip.c:11128
#5  0x002a91cb in sipsock_read (id=0x8b32a80, fd=19, events=1, ignore=0x0)
    at chan_sip.c:11243
#6  0x0805611d in ast_io_wait (ioc=0x8b29330, howlong=234) at io.c:285
#7  0x002a19d8 in do_monitor (data=0x0) at chan_sip.c:11388
#8  0x00876b80 in start_thread () from /lib/libpthread.so.0
#9  0x005ab9ce in clone () from /lib/libc.so.6