(gdb) frame 0
#0  0x0807da7e in __ast_pthread_mutex_lock (filename=0x813f9b3 "channel.c", lineno=2190, func=0x8141840 "__ast_read", 
    mutex_name=0x8140853 "&chan->lock", t=0xaaa6e50) at /usr/src/asterisk-test/1.4.12/asterisk-1.4.12/include/asterisk/lock.h:310
310                             t->thread[t->reentrancy] = pthread_self();
(gdb) p *t
$1 = {mutex = {__m_reserved = 2, __m_count = 1, __m_owner = 0x4afa, __m_kind = 1, __m_lock = {__status = 1, __spinlock = 0}}, 
  track = 1, file = {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x88e ""}, lineno = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, 
  reentrancy = 135534656, func = {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}, thread = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0}}
(gdb) frame 1
#1  0x080842c6 in __ast_read (chan=0xaaa6dd8, dropaudio=0) at channel.c:2190
2190            ast_channel_lock(chan);
(gdb) p *chan
$2 = {tech = 0x4aa68e0, tech_pvt = 0xaa445f8, __begin_field = 0xaaa6de0, name = 0xa01dac8 "SIP/AFFM-p4130-0aa445f8", 
  language = 0xa01dae0 "en", musicclass = 0xa01dae8 "default", accountcode = 0xa01dae3 "affm", call_forward = 0x815c4fc "", 
  uniqueid = 0xa01dab8 "1191427178.8653", __end_field = 0xaaa6df8, __field_mgr = {pool = 0xa01daa8, size = 128, space = 60, 
    used = 68}, fds = {176, 178, -1, -1, -1, -1, 189, -1}, music_state = 0x0, generatordata = 0x0, generator = 0x0, 
  _bridge = 0xb5a46d50, masq = 0x0, masqr = 0x0, cdrflags = 0, _softhangup = 0, whentohangup = 0, blocker = 26147744, lock = {
    mutex = {__m_reserved = 2, __m_count = 1, __m_owner = 0x4afa, __m_kind = 1, __m_lock = {__status = 1, __spinlock = 0}}, 
    track = 1, file = {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x88e ""}, lineno = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, 
    reentrancy = 135534656, func = {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}, thread = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0}}, 
  blockproc = 0x81416bd "ast_waitfor_nandfds", appl = 0xb8f721 "annels %s and %s compatible for bridge\n", 
  data = 0xb59088b0 "SIP/65.90.46.163-b5930468", fdno = 6, sched = 0x9d64038, streamid = -1, stream = 0x0, vstreamid = 0, 
  vstream = 0x0, oldwriteformat = 0, timingfd = 189, timingfunc = 0, timingdata = 0x0, _state = AST_STATE_UP, rings = 0, cid = {
    cid_dnid = 0x0, cid_num = 0x9fc4d68 "4134384130", cid_name = 0x9dc0b70 "", cid_ani = 0x9fc4d58 "8608035306", cid_rdnis = 0x0, 
    cid_pres = 0, cid_ani2 = 0, cid_ton = 0, cid_tns = 0}, dtmfq = '\0' <repeats 79 times>, dtmff = {frametype = 0, subclass = 0, 
    datalen = 0, samples = 0, mallocd = 0, mallocd_hdr_len = 0, offset = 0, src = 0x0, data = 0x0, delivery = {tv_sec = 0, 
      tv_usec = 0}, frame_list = {next = 0x0}, has_timing_info = 0, ts = 0, len = 0, seqno = 0}, 
  context = "affm", '\0' <repeats 75 times>, exten = "\000134384130", '\0' <repeats 69 times>, priority = 1, 
  macrocontext = '\0' <repeats 79 times>, macroexten = '\0' <repeats 79 times>, macropriority = 0, 
  dialcontext = "\000stn-in", '\0' <repeats 72 times>, pbx = 0x0, amaflags = 3, cdr = 0xa4c03f0, adsicpe = AST_ADSI_UNAVAILABLE, 
  zone = 0x0, monitor = 0x0, insmpl = 0, outsmpl = 0, fin = 584, fout = 766, hangupcause = 16, varshead = {first = 0x9ec7420, 
    last = 0x9dc1f38}, callgroup = 0, pickupgroup = 0, flags = 1056, transfercapability = 0, readq = {first = 0xb5975bc8, 
    last = 0xb5975bc8}, alertpipe = {-1, -1}, nativeformats = 256, readformat = 64, writeformat = 64, writetrans = 0x9dada40, 
  readtrans = 0x9dd5640, rawreadformat = 256, rawwriteformat = 256, spies = 0x0, whisper = 0x0, chan_list = {next = 0xb5a46d50}, 
  jb = {conf = {flags = 0, max_size = -1, resync_threshold = -1, impl = '\0' <repeats 11 times>}, impl = 0x0, jbobj = 0x0, 
    timebase = {tv_sec = 0, tv_usec = 0}, next = 0, last_format = 0, logfile = 0x0, flags = 0}, emulate_dtmf_digit = 0 '\0', 
  emulate_dtmf_duration = 0, dtmf_tv = {tv_sec = 0, tv_usec = 0}, datastores = {first = 0x0, last = 0x0}}