1 files changed, 34 insertions, 10 deletions

diff --git a/mm/memory.c b/mm/memory.c
index bde42c6d3633..b6e5fd23cc5a 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -307,7 +307,6 @@ void free_pgd_range(struct mmu_gather *tlb,
 {
         pgd_t *pgd;
         unsigned long next;
-        unsigned long start;
 
         /*
          * The next few lines have given us lots of grief...
@@ -351,7 +350,6 @@ void free_pgd_range(struct mmu_gather *tlb,
         if (addr > end - 1)
                 return;
 
-        start = addr;
         pgd = pgd_offset(tlb->mm, addr);
         do {
                 next = pgd_addr_end(addr, end);
@@ -2008,11 +2006,10 @@ int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
 {
         pgd_t *pgd;
         unsigned long next;
-        unsigned long start = addr, end = addr + size;
+        unsigned long end = addr + size;
         int err;
 
         BUG_ON(addr >= end);
-        mmu_notifier_invalidate_range_start(mm, start, end);
         pgd = pgd_offset(mm, addr);
         do {
                 next = pgd_addr_end(addr, end);
@@ -2020,7 +2017,7 @@ int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
                 if (err)
                         break;
         } while (pgd++, addr = next, addr != end);
-        mmu_notifier_invalidate_range_end(mm, start, end);
+
         return err;
 }
 EXPORT_SYMBOL_GPL(apply_to_page_range);
@@ -2630,6 +2627,7 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
         swp_entry_t entry;
         pte_t pte;
         struct mem_cgroup *ptr = NULL;
+        int exclusive = 0;
         int ret = 0;
 
         if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
@@ -2724,10 +2722,12 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
         if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) {
                 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
                 flags &= ~FAULT_FLAG_WRITE;
+                ret |= VM_FAULT_WRITE;
+                exclusive = 1;
         }
         flush_icache_page(vma, page);
         set_pte_at(mm, address, page_table, pte);
-        page_add_anon_rmap(page, vma, address);
+        do_page_add_anon_rmap(page, vma, address, exclusive);
         /* It's better to call commit-charge after rmap is established */
         mem_cgroup_commit_charge_swapin(page, ptr);
 
@@ -2760,6 +2760,26 @@ out_release:
 }
 
 /*
+ * This is like a special single-page "expand_downwards()",
+ * except we must first make sure that 'address-PAGE_SIZE'
+ * doesn't hit another vma.
+ *
+ * The "find_vma()" will do the right thing even if we wrap
+ */
+static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned long address)
+{
+        address &= PAGE_MASK;
+        if ((vma->vm_flags & VM_GROWSDOWN) && address == vma->vm_start) {
+                address -= PAGE_SIZE;
+                if (find_vma(vma->vm_mm, address) != vma)
+                        return -ENOMEM;
+
+                expand_stack(vma, address);
+        }
+        return 0;
+}
+
+/*
  * We enter with non-exclusive mmap_sem (to exclude vma changes,
  * but allow concurrent faults), and pte mapped but not yet locked.
  * We return with mmap_sem still held, but pte unmapped and unlocked.
@@ -2772,19 +2792,23 @@ static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
         spinlock_t *ptl;
         pte_t entry;
 
+        pte_unmap(page_table);
+
+        /* Check if we need to add a guard page to the stack */
+        if (check_stack_guard_page(vma, address) < 0)
+                return VM_FAULT_SIGBUS;
+
+        /* Use the zero-page for reads */
         if (!(flags & FAULT_FLAG_WRITE)) {
                 entry = pte_mkspecial(pfn_pte(my_zero_pfn(address),
                                                 vma->vm_page_prot));
-                ptl = pte_lockptr(mm, pmd);
-                spin_lock(ptl);
+                page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
                 if (!pte_none(*page_table))
                         goto unlock;
                 goto setpte;
         }
 
         /* Allocate our own private page. */
-        pte_unmap(page_table);
-
         if (unlikely(anon_vma_prepare(vma)))
                 goto oom;
         page = alloc_zeroed_user_highpage_movable(vma, address);