Merge branch 'master'; commit 'v2.6.39-rc3' into next

1 files changed, 9 insertions, 2 deletions

diff --git a/mm/mremap.c b/mm/mremap.c
index 1de98d492ddc..a7c1f9f9b941 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -277,9 +277,16 @@ static struct vm_area_struct *vma_to_resize(unsigned long addr,
         if (old_len > vma->vm_end - addr)
                 goto Efault;
 
-        if (vma->vm_flags & (VM_DONTEXPAND | VM_PFNMAP)) {
-                if (new_len > old_len)
+        /* Need to be careful about a growing mapping */
+        if (new_len > old_len) {
+                unsigned long pgoff;
+
+                if (vma->vm_flags & (VM_DONTEXPAND | VM_PFNMAP))
                         goto Efault;
+                pgoff = (addr - vma->vm_start) >> PAGE_SHIFT;
+                pgoff += vma->vm_pgoff;
+                if (pgoff + (new_len >> PAGE_SHIFT) < pgoff)
+                        goto Einval;
         }
 
         if (vma->vm_flags & VM_LOCKED) {