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- C MP+polocks
- (*
- * Result: Never
- *
- * This litmus test demonstrates how lock acquisitions and releases can
- * stand in for smp_load_acquire() and smp_store_release(), respectively.
- * In other words, when holding a given lock (or indeed after releasing a
- * given lock), a CPU is not only guaranteed to see the accesses that other
- * CPUs made while previously holding that lock, it is also guaranteed
- * to see all prior accesses by those other CPUs.
- *)
- {}
- P0(int *buf, int *flag, spinlock_t *mylock) // Producer
- {
- WRITE_ONCE(*buf, 1);
- spin_lock(mylock);
- WRITE_ONCE(*flag, 1);
- spin_unlock(mylock);
- }
- P1(int *buf, int *flag, spinlock_t *mylock) // Consumer
- {
- int r0;
- int r1;
- spin_lock(mylock);
- r0 = READ_ONCE(*flag);
- spin_unlock(mylock);
- r1 = READ_ONCE(*buf);
- }
- exists (1:r0=1 /\ 1:r1=0) (* Bad outcome. *)
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