queue-2.6.22.y/grab-swap-token-oops.patch

   1 From: Dean Roe <roe@sgi.com>
   2 Subject: Prevent NULL pointer deref in grab_swap_token
   3 References: 159260
   4
   5 grab_swap_token() assumes that the current process has an mm struct,
   6 which is not true for kernel threads invoking get_user_pages().  Since
   7 this should be extremely rare, just return from grab_swap_token()
   8 without doing anything.
   9
  10 Signed-off-by: Dean Roe <roe@sgi.com>
  11 Acked-by: mason@suse.de
  12 Acked-by: okir@suse.de
  13 Signed-off-by: Oliver Pinter <oliver.pntr@gmail.com>
  14
  15
  16  mm/thrash.c |    3 +++
  17  1 file changed, 3 insertions(+)
  18
  19 --- a/mm/thrash.c       2007-07-08 19:32:17.000000000 -0400
  20 +++ b/mm/thrash.c       2007-08-27 14:01:21.000000000 -0400
  21 @@ -31,6 +31,9 @@ void grab_swap_token(void)
  22         int current_interval;
  23
  24         global_faults++;
  25 +       if (current->mm == NULL)
  26 +               return;
  27 +
  28
  29         current_interval = global_faults - current->mm->faultstamp;
  30