(gdb) set pagination off
(gdb) bt
#0  0x0073775e in _int_malloc () from /lib/tls/libc.so.6
#1  0x007396e1 in malloc () from /lib/tls/libc.so.6
#2  0x08067764 in ast_expr ()
#3  0x080eaccf in pbx_substitute_variables_helper_full ()
#4  0x080f14e0 in pbx_extension_helper ()
#5  0x080f27e5 in __ast_pbx_run ()
#6  0x080f4dc1 in pbx_thread ()
#7  0x08127272 in dummy_start ()
#8  0x008853cc in start_thread () from /lib/tls/libpthread.so.0
#9  0x0079dc3e in clone () from /lib/tls/libc.so.6

(gdb) bt full
#0  0x0073775e in _int_malloc () from /lib/tls/libc.so.6
No symbol table info available.
#1  0x007396e1 in malloc () from /lib/tls/libc.so.6
No symbol table info available.
#2  0x08067764 in ast_expr ()
No symbol table info available.
#3  0x080eaccf in pbx_substitute_variables_helper_full ()
No symbol table info available.
#4  0x080f14e0 in pbx_extension_helper ()
No symbol table info available.
#5  0x080f27e5 in __ast_pbx_run ()
No symbol table info available.
#6  0x080f4dc1 in pbx_thread ()
No symbol table info available.
#7  0x08127272 in dummy_start ()
No symbol table info available.
#8  0x008853cc in start_thread () from /lib/tls/libpthread.so.0
No symbol table info available.
#9  0x0079dc3e in clone () from /lib/tls/libc.so.6
No symbol table info available.