On Wed, Dec 13, 2017 at 5:12 AM, Kirill A. Shutemov <[email protected]> wrote: > On Tue, Dec 12, 2017 at 07:56:38AM -0800, Andy Lutomirski wrote: >> The ESPFIX64 user mapping belongs in pti.c just like all the other >> user mappings. Move it there and make it work correctly while we're >> at it. >> >> Signed-off-by: Andy Lutomirski <[email protected]> > > Acked-by: Kirill A. Shutemov <[email protected]> > > BTW, why do we open-code p?d_alloc() in pti_user_pagetable_walk_*()? > It seems unnecessary and potentially bogus: see smp_wmb() in __p?d_alloc() > helpers.
The helpers won't work -- we're allocating kernel-owned tables in the usermode part of init_mm. The p?d_alloc() helpers allocate user-accounted tables in the kernelmode part of the mm. --Andy
