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C MP+onceassign+derefonce
(*
* Result: Never
*
* This litmus test demonstrates that rcu_assign_pointer() and
* rcu_dereference() suffice to ensure that an RCU reader will not see
* pre-initialization garbage when it traverses an RCU-protected data
* structure containing a newly inserted element.
*)
{
int *p=y;
int x;
int y=0;
}
P0(int *x, int **p) // Producer
{
WRITE_ONCE(*x, 1);
rcu_assign_pointer(*p, x);
}
P1(int *x, int **p) // Consumer
{
int *r0;
int r1;
rcu_read_lock();
r0 = rcu_dereference(*p);
r1 = READ_ONCE(*r0);
rcu_read_unlock();
}
exists (1:r0=x /\ 1:r1=0) (* Bad outcome. *)
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