> On Dec 14, 2017, at 2:15 PM, Linus Torvalds <torva...@linux-foundation.org> > wrote: > >> On Thu, Dec 14, 2017 at 2:11 PM, Andy Lutomirski <l...@amacapital.net> wrote: >> >> That seems to rather defeat the point of using a VMA, though. > > There never was any point in using a VMA per se. > > The point was always to just map the damn thing in the user page > tables, wasn't it? > > The vma bit was just an implementation detail.
And all this is why I dislike using a VMA. My patch puts it at a negative address. We could just as easily put it just above TASK_SIZE_MAX, but I'm a bit nervous about bugs that overrun an access_ok check by a small amount. IIRC I found one of those in the net code once, and I didn't look very hard.
