On Wed, Dec 13, 2017 at 10:25:49AM +0100, Michal Hocko wrote: > +++ b/mm/mmap.c > @@ -1342,6 +1342,10 @@ unsigned long do_mmap(struct file *file, unsigned long addr, > if (!(file && path_noexec(&file->f_path))) > prot |= PROT_EXEC; > > + /* force arch specific MAP_FIXED handling in get_unmapped_area */ > + if (flags & MAP_FIXED_SAFE) > + flags |= MAP_FIXED; > + > if (!(flags & MAP_FIXED)) > addr = round_hint_to_min(addr); > We're up to 22 MAP_ flags now. We'll run out soon. Let's preserve half of a flag by giving userspace the definition: #define MAP_FIXED_SAFE (MAP_FIXED | _MAP_NOT_HINT) then in here: if ((flags & _MAP_NOT_HINT) && !(flags & MAP_FIXED)) return -EINVAL; Now we can use _MAP_NOT_HINT all by itself in the future to mean something else. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
