(gdb) bt full
#0  0xb741dab0 in __sip_destroy (p=0xb6b0a9d0, lockowner=1) at chan_sip.c:2950
        this = (struct ast_string_field_pool *) 0x302074
        prev = <value optimized out>
        cur = <value optimized out>
        cp = (struct sip_pkt *) 0x0
        __PRETTY_FUNCTION__ = "__sip_destroy"
#1  0xb742f2cc in __sip_autodestruct (data=0xb6b0a9d0) at chan_sip.c:3081
        p = (struct sip_pvt *) 0x302074
        __PRETTY_FUNCTION__ = "__sip_autodestruct"
#2  0x080e27fc in ast_sched_runq (con=0x81b56d0) at sched.c:358
        numevents = 0
        res = <value optimized out>
#3  0xb7436e04 in do_monitor (data=0x0) at chan_sip.c:14863
        prev = <value optimized out>
        res = 5
        sip = (struct sip_pvt *) 0x0
        t = 1181130703
        fastrestart = 0
        lastpeernum = -1
        curpeernum = 45
        reloading = <value optimized out>
        __PRETTY_FUNCTION__ = "do_monitor"
#4  0x080ed780 in dummy_start (data=0x81b9ae8) at utils.c:545
        _buffer = {__routine = 0x8069ad0 <ast_unregister_thread>, __arg = 0x20008, __canceltype = -1210627232, __prev = 0x0}
        ret = <value optimized out>
#5  0xb7f01b51 in pthread_start_thread () from /lib/libpthread.so.0
No symbol table info available.
#6  0xb7d3874a in clone () from /lib/libc.so.6
No symbol table info available.