On Thu, Apr 15, 2021 at 03:14:05PM -0700, Yu-cheng Yu wrote: > When serving a page fault, maybe_mkwrite() makes a PTE writable if it is in > a writable vma. A shadow stack vma is writable, but its PTEs need > _PAGE_DIRTY to be set to become writable. For this reason, maybe_mkwrite() > has been updated. > > There are a few places that call pte_mkwrite() directly, but have the > same result as from maybe_mkwrite(). These sites need to be updated for > shadow stack as well. Thus, change them to maybe_mkwrite(): > > - do_anonymous_page() and migrate_vma_insert_page() check VM_WRITE directly > and call pte_mkwrite(), which is the same as maybe_mkwrite(). Change > them to maybe_mkwrite(). > > - In do_numa_page(), if the numa entry was writable, then pte_mkwrite() > is called directly. Fix it by doing maybe_mkwrite(). Make the same > changes to do_huge_pmd_numa_page(). > > - In change_pte_range(), pte_mkwrite() is called directly. Replace it with > maybe_mkwrite(). > > Signed-off-by: Yu-cheng Yu <yu-cheng.yu@xxxxxxxxx> > Cc: Kees Cook <keescook@xxxxxxxxxxxx> Reviewed-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> -- Kirill A. Shutemov
