LXR linux/tools/memory-model/litmus-tests/R+poonceonces.litmus

   1C R+poonceonces
   2
   3(*
   4 * Result: Sometimes
   5 *
   6 * This is the unordered (thus lacking smp_mb()) version of one of the
   7 * classic counterintuitive litmus tests that illustrates the effects of
   8 * store propagation delays.
   9 *)
  10
  11{}
  12
  13P0(int *x, int *y)
  14{
  15        WRITE_ONCE(*x, 1);
  16        WRITE_ONCE(*y, 1);
  17}
  18
  19P1(int *x, int *y)
  20{
  21        int r0;
  22
  23        WRITE_ONCE(*y, 2);
  24        r0 = READ_ONCE(*x);
  25}
  26
  27exists (y=2 /\ 1:r0=0)
  28