[ARM] 4379/1: AT91: LCD support on SAM9261-EK and SAM9263-EK boards

[linux-2.6-omap-h63xx.git] / mm / mmap.c

diff --git a/mm/mmap.c b/mm/mmap.c
index cc1f543eb1b85e1ddfce5927704f9763f3d74233..906ed402f7cabda336a73d6d0d297b862b0d2932 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1536,9 +1536,14 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
         * vma->vm_start/vm_end cannot change under us because the caller
         * is required to hold the mmap_sem in read mode.  We need the
         * anon_vma lock to serialize against concurrent expand_stacks.
+        * Also guard against wrapping around to address 0.
         */
-       address += 4 + PAGE_SIZE - 1;
-       address &= PAGE_MASK;
+       if (address < PAGE_ALIGN(address+4))
+               address = PAGE_ALIGN(address+4);
+       else {
+               anon_vma_unlock(vma);
+               return -ENOMEM;
+       }
        error = 0;
 
        /* Somebody else might have raced and expanded it already */
@@ -1720,7 +1725,7 @@ detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
 
 /*
  * Split a vma into two pieces at address 'addr', a new vma is allocated
- * either for the first part or the the tail.
+ * either for the first part or the tail.
  */
 int split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
              unsigned long addr, int new_below)