On Mon, Oct 28, 2019 at 03:31:24PM +0300, Kirill A. Shutemov wrote: > On Sun, Oct 27, 2019 at 12:17:32PM +0200, Mike Rapoport wrote: > > From: Mike Rapoport <rppt@xxxxxxxxxxxxx> > > > > The mappings created with MAP_EXCLUSIVE are visible only in the context of > > the owning process and can be used by applications to store secret > > information that will not be visible not only to other processes but to the > > kernel as well. > > > > The pages in these mappings are removed from the kernel direct map and > > marked with PG_user_exclusive flag. When the exclusive area is unmapped, > > the pages are mapped back into the direct map. > > I probably blind, but I don't see where you manipulate direct map... __get_user_pages() calls __set_page_user_exclusive() which in turn calls set_direct_map_invalid_noflush() that makes the page not present. > -- > Kirill A. Shutemov -- Sincerely yours, Mike.
