Merge tag 'lkdtm-next' of https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux...

[linux-2.6-microblaze.git] / mm / userfaultfd.c

diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 0cb8e5e..e9bb6db 100644 (file)
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -72,12 +72,15 @@ int mfill_atomic_install_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd,
        _dst_pte = pte_mkdirty(_dst_pte);
        if (page_in_cache && !vm_shared)
                writable = false;
-       if (writable) {
-               if (wp_copy)
-                       _dst_pte = pte_mkuffd_wp(_dst_pte);
-               else
-                       _dst_pte = pte_mkwrite(_dst_pte);
-       }
+
+       /*
+        * Always mark a PTE as write-protected when needed, regardless of
+        * VM_WRITE, which the user might change.
+        */
+       if (wp_copy)
+               _dst_pte = pte_mkuffd_wp(_dst_pte);
+       else if (writable)
+               _dst_pte = pte_mkwrite(_dst_pte);
 
        dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl);