(gdb) bt
#0  0x0814af3e in __ast_pthread_mutex_lock (filename=0x81be8c0 "sched.c", lineno=221, func=0x81bec2d "ast_sched_add_variable",
    mutex_name=0x81be94b "&con->lock", t=0x0) at /home/pabelanger/svn/asterisk-1.6.0/include/asterisk/lock.h:372
#1  0x0814bd3e in ast_sched_add_variable (con=0x0, when=2000, callback=0x8152d7d <send_sigurg>, data=0xb6b3e890, variable=0) at sched.c:221
#2  0x0814bead in ast_sched_add (con=0x0, when=2000, callback=0x8152d7d <send_sigurg>, data=0xb6b3e890) at sched.c:255
#3  0x0815380b in ast_tcptls_client_start (desc=0xb6b3e910) at tcptls.c:290
#4  0xb6bab2df in sip_prepare_socket (p=0x823d7f0) at chan_sip.c:18733
#5  0xb6b54ef9 in __sip_xmit (p=0x823d7f0,
    data=0xb6b3ffcc "OPTIONS sip:hound.vopella.com SIP/2.0\r\nVia: SIP/2.0/TCP 172.16.1.4:5068;branch=z9hG4bK09d16f19;rport\r\nMax-Forwards: 70\r\nFrom: \"asterisk\" <sip:asterisk@172.16.1.4>;tag=as6009d016\r\nTo: <sip:hound.vopell"..., len=549) at chan_sip.c:2589
#6  0xb6b5646c in __sip_reliable_xmit (p=0x823d7f0, seqno=102, resp=0,
    data=0xb6b3ffcc "OPTIONS sip:hound.vopella.com SIP/2.0\r\nVia: SIP/2.0/TCP 172.16.1.4:5068;branch=z9hG4bK09d16f19;rport\r\nMax-Forwards: 70\r\nFrom: \"asterisk\" <sip:asterisk@172.16.1.4>;tag=as6009d016\r\nTo: <sip:hound.vopell"..., len=549, fatal=1, sipmethod=3) at chan_sip.c:2875
#7  0xb6b57d34 in send_request (p=0x823d7f0, req=0xb6b3fda8, reliable=XMIT_CRITICAL, seqno=102) at chan_sip.c:3180
#8  0xb6b75258 in transmit_invite (p=0x823d7f0, sipmethod=3, sdp=0, init=2) at chan_sip.c:8932
#9  0xb6bae3c9 in sip_poke_peer (peer=0x8228388) at chan_sip.c:19477
#10 0xb6b7a720 in sip_poke_peer_s (data=0x8228388) at chan_sip.c:9741
#11 0x0814c4ea in ast_sched_runq (con=0x8267500) at sched.c:369
#12 0xb6bac334 in do_monitor (data=0x0) at chan_sip.c:19034
#13 0x0816033f in dummy_start (data=0x823a2f8) at utils.c:917
#14 0xb7e064fb in start_thread () from /lib/tls/i686/cmov/libpthread.so.0
#15 0xb7ef4e5e in clone () from /lib/tls/i686/cmov/libc.so.6