On Tue, Sep 17, 2019 at 09:36:06AM -0700, Matthew Wilcox wrote: > If the copy has the correct bounds, the 'wholly within one base page' > check will pass and it'll return. If the copy does span a page, > the virt_to_head_page(end) call will return something bogus, then the > PageReserved and CMA test will cause the usercopy_abort() test to fail. > > So I think your first patch is the right patch. Okay, good points. I'll respin... -- Kees Cook