You need to identify what the "last lockecd" location is, something like: gdb netbsd.gdb # or just netbsd, if you do not have a netbsd.gdb gdb> list *(0xffffffff80ea0a90) (I never can remember the equivalent addr2line flags for this, probably: addr2line -a 0xffffffff80ea0a90 -e netbsd.gdb) Martin