(gdb) bt
#0  0xb7cab9f0 in lintoalaw_framein (pvt=0x9f, f=0x0) at codec_alaw.c:81
#1  0x080efbbb in framein (pvt=0x8c993d8, f=0x8bca5ac) at translate.c:187
#2  0x080f017a in ast_translate (path=0x8c993d8, f=0x8bca5ac, consume=0) at translate.c:332
#3  0xb7508836 in conf_run (chan=0xb66b4748, conf=0x8c45400, confflags=33060, optargs=0xb735c06c) at app_meetme.c:2136
#4  0xb750bb5c in conf_exec (chan=0xb66b4748, data=0xb735d4fc) at app_meetme.c:2698
#5  0x080bbfac in pbx_exec (c=0xb66b4748, app=0xb7998ad0, data=0xb735d4fc) at pbx.c:528
#6  0xb75543f1 in handle_exec (chan=0xa0, agi=0xa0, argc=3, argv=0xb735d2f0) at res_agi.c:1116
#7  0xb7556798 in agi_exec_full (chan=0xb66b4748, data=Variable "data" is not available.
) at res_agi.c:1812
#8  0x080c6b01 in pbx_extension_helper (c=0xb66b4748, con=Variable "con" is not available.
) at pbx.c:528
#9  0x080c7e3f in __ast_pbx_run (c=0xb66b4748) at pbx.c:2270
#10 0x080c9cee in pbx_thread (data=0xa0) at pbx.c:2583
#11 0x080f5c05 in dummy_start (data=0x9f) at utils.c:545
#12 0xb7f86ce1 in pthread_start_thread () from /lib/i686/libpthread.so.0
#13 0xb7ef9d3a in clone () from /lib/i686/libc.so.6
(gdb) bt full
#0  0xb7cab9f0 in lintoalaw_framein (pvt=0x9f, f=0x0) at codec_alaw.c:81
        i = 159
        dst = 0x8c99484 "öñõËÍÆÛÒÐÖTWQ_^XEG@MCBFEXSWÕÑÓÜÞØÛØÙÞßÒÐÑ×ÔÔÕUTWWWP\\^GCMKIIKIMGY]RVQSRRSWÖÝÇÍËöóýüüóöôÏÅÜW_DKtvpppprppqvuuOKIIKAYVÜÁõýûåççççäùóõÃÓVZOt}~{dggffgge{ysKDÕÄõýûäááæç"
        src = (int16_t *) 0x0
#1  0x080efbbb in framein (pvt=0x8c993d8, f=0x8bca5ac) at translate.c:187
        dst = (int16_t *) 0x8c99484
        ret = 160
        samples = 0
        __PRETTY_FUNCTION__ = "framein"
#2  0x080f017a in ast_translate (path=0x8c993d8, f=0x8bca5ac, consume=0) at translate.c:332
        p = (struct ast_trans_pvt *) 0x8c993d8
        out = (struct ast_frame *) 0x8bca5ac
        delivery = warning: Unhandled dwarf expresion opcode DW_OP_piece
{tv_sec = 0, tv_usec = 0}
        has_timing_info = 0
        ts = 0
        len = 0
        seqno = 0
#3  0xb7508836 in conf_run (chan=0xb66b4748, conf=0x8c45400, confflags=33060, optargs=0xb735c06c) at app_meetme.c:2136
        index = 3
        usr = Variable "usr" is not available.
(gdb) 
(gdb) thread apply all bt

Thread 58 (process 26896):
#0  0x00000296 in ?? ()
Cannot access memory at address 0x0
0xb7cab9f0      81                      *dst++ = AST_LIN2A(*src++);