(gdb) bt
#0  0x0807cc22 in ast_bridged_channel (chan=0x81c8040) at channel.c:3599
#1  0x40afe4fc in handle_request_invite (p=0x81c9598, req=0x40b68760, debug=1, seqno=1, sin=0x40b68750, recount=0x81c8940, 
    e=0x81c8940 " combined - 0x1 (telephone-event)\n") at chan_sip.c:14266
#2  0x40afd111 in handle_request (p=0x81c9598, req=0x40b68760, sin=0x40b68750, recount=0x81c8940, nounlock=0x81c8940) at chan_sip.c:15333
#3  0x40af7d98 in sipsock_read (id=0x8185e80, fd=14, events=1, ignore=0x0) at chan_sip.c:15480
#4  0x080a04e0 in ast_io_wait (ioc=0x81720d0, howlong=136087872) at io.c:292
#5  0x40ae809a in do_monitor (data=0x0) at chan_sip.c:15697
#6  0x080edb89 in dummy_start (data=0x6d6f6320) at utils.c:545
#7  0x40155b63 in start_thread () from /lib/tls/libpthread.so.0
#8  0x4036f18a in clone () from /lib/tls/libc.so.6
(gdb)