vm: fix vm_pgoff wrap in upward expansion
authorHugh Dickins <hughd@google.com>
Tue, 10 May 2011 00:44:42 +0000 (17:44 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 10 May 2011 00:52:17 +0000 (17:52 -0700)
Commit a626ca6a6564 ("vm: fix vm_pgoff wrap in stack expansion") fixed
the case of an expanding mapping causing vm_pgoff wrapping when you had
downward stack expansion.  But there was another case where IA64 and
PA-RISC expand mappings: upward expansion.

This fixes that case too.

Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/mmap.c

index e27e0cf0de03ccb81b252953932fc356c3499c10..772140c53ab185ebc76d1f185d6feb9fb8935c15 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1767,10 +1767,13 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
                size = address - vma->vm_start;
                grow = (address - vma->vm_end) >> PAGE_SHIFT;
 
-               error = acct_stack_growth(vma, size, grow);
-               if (!error) {
-                       vma->vm_end = address;
-                       perf_event_mmap(vma);
+               error = -ENOMEM;
+               if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) {
+                       error = acct_stack_growth(vma, size, grow);
+                       if (!error) {
+                               vma->vm_end = address;
+                               perf_event_mmap(vma);
+                       }
                }
        }
        vma_unlock_anon_vma(vma);