mm: prevent potential recursive reclaim due to clearing PF_MEMALLOC

[mirror_ubuntu-zesty-kernel.git] / mm / ksm.c

diff --git a/mm/ksm.c b/mm/ksm.c
index fed4afd8293bdb5096c6f790a59f3a1e37e87497..099dfa45d596cb222f26a6f90e1255e2e8350ab7 100644 (file)
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -878,7 +878,8 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page,
        if (!ptep)
                goto out_mn;
 
-       if (pte_write(*ptep) || pte_dirty(*ptep)) {
+       if (pte_write(*ptep) || pte_dirty(*ptep) ||
+           (pte_protnone(*ptep) && pte_savedwrite(*ptep))) {
                pte_t entry;
 
                swapped = PageSwapCache(page);
@@ -903,7 +904,11 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page,
                }
                if (pte_dirty(entry))
                        set_page_dirty(page);
-               entry = pte_mkclean(pte_wrprotect(entry));
+
+               if (pte_protnone(entry))
+                       entry = pte_mkclean(pte_clear_savedwrite(entry));
+               else
+                       entry = pte_mkclean(pte_wrprotect(entry));
                set_pte_at_notify(mm, addr, ptep, entry);
        }
        *orig_pte = *ptep;