[$] MAP_FIXED_SAFE

The MAP_FIXED option to the mmap()system call allows a process to specify that a mapping should be placedat a given virtual address if at all possible. It turns out, though, that"if at all possible" can involve a bit more collateral damage than somewould like, and can even lead to exploitable vulnerabilities. A new, saferoption is in the works but, as is often the case, it has run into a bit ofnon-technical difficulty.