(gdb) bt
#0  0x00a8b7a2 in _dl_sysinfo_int80 () from /lib/ld-linux.so.2
#1  0x00acb955 in raise () from /lib/tls/libc.so.6
#2  0x00acd319 in abort () from /lib/tls/libc.so.6
#3  0x00b04a1b in malloc_printerr () from /lib/tls/libc.so.6
#4  0x00b054ba in free () from /lib/tls/libc.so.6
#5  0xb7c3cc7f in __sip_ack (p=0xb597ca28, seqno=137266768, resp=1, sipmethod=0) at chan_sip.c:1439
#6  0xb7c6ccb9 in handle_request (p=0xb597ca28, req=0xb78ebb90, sin=0xb78ebb80, recount=0x0, nounlock=0x0)
    at chan_sip.c:11157
#7  0xb7c6ef12 in sipsock_read (id=0x8138e80, fd=144, events=1, ignore=0x0) at chan_sip.c:11250
#8  0x08055edf in ast_io_wait (ioc=0x8137a50, howlong=0) at io.c:285
#9  0xb7c74ca1 in do_monitor (data=0x0) at chan_sip.c:11395
#10 0x00ce91d5 in start_thread () from /lib/tls/libpthread.so.0
#11 0x00b692da in clone () from /lib/tls/libc.so.6

(gdb) bt full
#0  0x00a8b7a2 in _dl_sysinfo_int80 () from /lib/ld-linux.so.2
No symbol table info available.
#1  0x00acb955 in raise () from /lib/tls/libc.so.6
No symbol table info available.
#2  0x00acd319 in abort () from /lib/tls/libc.so.6
No symbol table info available.
#3  0x00b04a1b in malloc_printerr () from /lib/tls/libc.so.6
No symbol table info available.
#4  0x00b054ba in free () from /lib/tls/libc.so.6
No symbol table info available.
#5  0xb7c3cc7f in __sip_ack (p=0xb597ca28, seqno=137266768, resp=1, sipmethod=0) at chan_sip.c:1439
        cur = (struct sip_pkt *) 0xbc8800
        prev = (struct sip_pkt *) 0xb597ca28
        res = -1
        msg = 0x0
        __PRETTY_FUNCTION__ = "__sip_ack"
#6  0xb7c6ccb9 in handle_request (p=0xb597ca28, req=0xb78ebb90, sin=0xb78ebb80, recount=0x0, nounlock=0x0)
    at chan_sip.c:11157
        resp = {rlPart1 = 0x0, rlPart2 = 0x0, len = 0, headers = 0, method = 0, header = {0x0 <repeats 64 times>},
  lines = 0, line = {0x0 <repeats 64 times>}, data = '\0' <repeats 4095 times>, debug = 0, flags = 0}
        cmd = 0xffffffff <Address 0xffffffff out of bounds>
        seqno = 9247163
        len = 7
        ignore = 0
        respid = 200
        res = 0
        iabuf = "\177­\216?غ\216?\000\000\000\000غ\216?"
        e = 0xb78ebdac "sip:2318@172.22.22.1"
        __PRETTY_FUNCTION__ = "handle_request"
#7  0xb7c6ef12 in sipsock_read (id=0x8138e80, fd=144, events=1, ignore=0x0) at chan_sip.c:11250
        req = {rlPart1 = 0xb78ebda8 "ACK", rlPart2 = 0xb78ebdac "sip:2318@172.22.22.1", len = 348, headers = 9, method = 6,
  header = {0xb78ebda8 "ACK", 0xb78ebdca "Via: SIP/2.0/UDP 172.22.22.18;branch=z9hG4bKacVTUuyRG",
    0xb78ebe01 "From: <sip:2191@172.22.22.18>;tag=1c8359", 0xb78ebe2b "To: <sip:2318@172.22.22.1>;tag=as0b739d50",
    0xb78ebe56 "Call-ID: 184282247822478WuEU-2191--2318@172.22.22.18", 0xb78ebe8c "CSeq: 9247163 ACK",
    0xb78ebe9f "Max-Forwards: 70", 0xb78ebeb1 "User-Agent: Audiocodes-Sip-Gateway-MP-124 FXS/v.4.20.354.571",
    0xb78ebeef "Content-Length: 0", 0xb78ebf02 "", 0x0 <repeats 54 times>}, lines = 0, line = {0xb78ebf04 "",
    0x0 <repeats 63 times>},
  data = "ACK\000sip:2318@172.22.22.1\000SIP/2.0\000\000Via: SIP/2.0/UDP 172.22.22.18;branch=z9hG4bKacVTUuyRG\000\000From: <sip:2191@172.22.22.18>;tag=1c8359\000\000To: <sip:2318@172.22.22.1>;tag=as0b739d50\000\000Call-ID: 184282247822478Wu"...,
  debug = 0, flags = 0}
        sin = {sin_family = 2, sin_port = 50195, sin_addr = {s_addr = 303437484}, sin_zero = "\000\000\000\000\000\000\000"}
        res = -1215382956
        len = 16
        nounlock = 0
        recount = 0
        iabuf = '\0' <repeats 15 times>
        __PRETTY_FUNCTION__ = "sipsock_read"
#8  0x08055edf in ast_io_wait (ioc=0x8137a50, howlong=0) at io.c:285
        res = 1
        x = 0
        origcnt = 1
#9  0xb7c74ca1 in do_monitor (data=0x0) at chan_sip.c:11395
        res = 0
        sip = (struct sip_pvt *) 0x8137a50
        peer = (struct sip_peer *) 0x0
        t = 1139293955
        fastrestart = 0
        lastpeernum = -1
        curpeernum = 579
        reloading = 135494224
        __PRETTY_FUNCTION__ = "do_monitor"
#10 0x00ce91d5 in start_thread () from /lib/tls/libpthread.so.0
No symbol table info available.
#11 0x00b692da in clone () from /lib/tls/libc.so.6
No symbol table info available.
(gdb)