b6ff30849c
This commit adds comments that label the MP tests' producer and consumer processes, and also that label the "exists" clause as the bad outcome. Reported-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
35 lines
617 B
Text
35 lines
617 B
Text
C MP+onceassign+derefonce
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(*
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* Result: Never
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*
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* This litmus test demonstrates that rcu_assign_pointer() and
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* rcu_dereference() suffice to ensure that an RCU reader will not see
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* pre-initialization garbage when it traverses an RCU-protected data
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* structure containing a newly inserted element.
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*)
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{
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int *p=y;
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int x;
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int y=0;
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}
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P0(int *x, int **p) // Producer
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{
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WRITE_ONCE(*x, 1);
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rcu_assign_pointer(*p, x);
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}
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P1(int *x, int **p) // Consumer
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{
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int *r0;
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int r1;
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rcu_read_lock();
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r0 = rcu_dereference(*p);
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r1 = READ_ONCE(*r0);
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rcu_read_unlock();
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}
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exists (1:r0=x /\ 1:r1=0) (* Bad outcome. *)
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