1 files changed, 21 insertions, 11 deletions

diff --git a/mm/memory.c b/mm/memory.c
index 4198df0dff1c..bf6100236e62 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1110,23 +1110,29 @@ static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd,
 {
         pte_t *pte;
         spinlock_t *ptl;
+        int err = 0;
 
         pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
         if (!pte)
-                return -ENOMEM;
+                return -EAGAIN;
         arch_enter_lazy_mmu_mode();
         do {
                 struct page *page = ZERO_PAGE(addr);
                 pte_t zero_pte = pte_wrprotect(mk_pte(page, prot));
+
+                if (unlikely(!pte_none(*pte))) {
+                        err = -EEXIST;
+                        pte++;
+                        break;
+                }
                 page_cache_get(page);
                 page_add_file_rmap(page);
                 inc_mm_counter(mm, file_rss);
-                BUG_ON(!pte_none(*pte));
                 set_pte_at(mm, addr, pte, zero_pte);
         } while (pte++, addr += PAGE_SIZE, addr != end);
         arch_leave_lazy_mmu_mode();
         pte_unmap_unlock(pte - 1, ptl);
-        return 0;
+        return err;
 }
 
 static inline int zeromap_pmd_range(struct mm_struct *mm, pud_t *pud,
@@ -1134,16 +1140,18 @@ static inline int zeromap_pmd_range(struct mm_struct *mm, pud_t *pud,
 {
         pmd_t *pmd;
         unsigned long next;
+        int err;
 
         pmd = pmd_alloc(mm, pud, addr);
         if (!pmd)
-                return -ENOMEM;
+                return -EAGAIN;
         do {
                 next = pmd_addr_end(addr, end);
-                if (zeromap_pte_range(mm, pmd, addr, next, prot))
-                        return -ENOMEM;
+                err = zeromap_pte_range(mm, pmd, addr, next, prot);
+                if (err)
+                        break;
         } while (pmd++, addr = next, addr != end);
-        return 0;
+        return err;
 }
 
 static inline int zeromap_pud_range(struct mm_struct *mm, pgd_t *pgd,
@@ -1151,16 +1159,18 @@ static inline int zeromap_pud_range(struct mm_struct *mm, pgd_t *pgd,
 {
         pud_t *pud;
         unsigned long next;
+        int err;
 
         pud = pud_alloc(mm, pgd, addr);
         if (!pud)
-                return -ENOMEM;
+                return -EAGAIN;
         do {
                 next = pud_addr_end(addr, end);
-                if (zeromap_pmd_range(mm, pud, addr, next, prot))
-                        return -ENOMEM;
+                err = zeromap_pmd_range(mm, pud, addr, next, prot);
+                if (err)
+                        break;
         } while (pud++, addr = next, addr != end);
-        return 0;
+        return err;
 }
 
 int zeromap_page_range(struct vm_area_struct *vma,