Core was generated by `/usr/sbin/asterisk -f -vvvg -c'.
Program terminated with signal 6, Aborted.
#0  0x00261402 in __kernel_vsyscall ()
(gdb) bt full
#0  0x00261402 in __kernel_vsyscall ()
No symbol table info available.
#1  0x0043ec00 in raise () from /lib/libc.so.6
No symbol table info available.
#2  0x00440451 in abort () from /lib/libc.so.6
No symbol table info available.
#3  0x004741fb in __libc_message () from /lib/libc.so.6
No symbol table info available.
#4  0x0047bf5d in _int_free () from /lib/libc.so.6
No symbol table info available.
#5  0x0047f5b0 in free () from /lib/libc.so.6
No symbol table info available.
#6  0x080a1463 in ast_frame_free (fr=0xb7727500, cache=1) at frame.c:369
No locals.
#7  0x0807e64a in ast_channel_spy_free (spy=0x8b8e5f8) at /usr/src/asterisk/include/asterisk/frame.h:390
        f = (struct ast_frame *) 0xb7727500
#8  0x00b4c530 in mixmonitor_thread (obj=0x8b8e5f8) at app_mixmonitor.c:209
        mixmonitor = (struct mixmonitor *) 0x8b8e5f8
        f = (struct ast_frame *) 0x0
        fs = (struct ast_filestream *) 0x8a601b8
        oflags = 577
        ext = 0x8b8e6c0 "gsm"
        errflag = 0
        __PRETTY_FUNCTION__ = "mixmonitor_thread"
#9  0x080f949c in dummy_start (data=0x8b7edf0) at utils.c:775
        __cancel_buf = {__cancel_jmp_buf = {{__cancel_jmp_buf = {5865460, 0, 112290704, 112288712, -804320226, -558761198},
      __mask_was_saved = 0}}, __pad = {0x6b16480, 0x0, 0x0, 0x0}}
        __cancel_routine = (void (*)(void *)) 0x8068cd1 <ast_unregister_thread>
        __cancel_arg = (void *) 0x6b16b90
        not_first_call = 0
        ret = (void *) 0x52156e
        a = {start_routine = 0xb4c29e <mixmonitor_thread>, data = 0x8b8e5f8,
  name = 0x8b7fc68 "mixmonitor_thread    started at [  301] app_mixmonitor.c launch_monitor_thread()"}
#10 0x005892db in start_thread () from /lib/libpthread.so.0
No symbol table info available.
#11 0x004e312e in clone () from /lib/libc.so.6
No symbol table info available.