(gdb) bt
#0  0xb7c9e847 in raise () from /lib/tls/libc.so.6
#1  0xb7ca00d9 in abort () from /lib/tls/libc.so.6
#2  0xb7cd2616 in __libc_message () from /lib/tls/libc.so.6
#3  0xb7cd8d4f in _int_free () from /lib/tls/libc.so.6
#4  0xb7cd90ea in free () from /lib/tls/libc.so.6
#5  0x0804e771 in slapt_is_required_by ()
#6  0x0805137a in slapt_get_obsolete_pkgs ()
#7  0x08055ce7 in slapt_pkg_action_upgrade_all ()
#8  0x08056972 in main ()
(gdb)