(gdb) bt full
#0  0x00d68402 in __kernel_vsyscall ()
No symbol table info available.
#1  0x0037e118 in raise () from /lib/libc.so.6
No symbol table info available.
#2  0x0037f888 in abort () from /lib/libc.so.6
No symbol table info available.
#3  0x003b322a in __libc_message () from /lib/libc.so.6
No symbol table info available.
#4  0x003b9124 in _int_free () from /lib/libc.so.6
No symbol table info available.
#5  0x003b965f in free () from /lib/libc.so.6
No symbol table info available.
#6  0x08061978 in ast_channel_free (chan=0x9a359c8) at channel.c:780
        cur = Variable "cur" is not available.
(gdb)