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Lines 41-47
static pthread_mutex_t race_mut;
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static pthread_cond_t sig1, sig2, sig3; |
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static pthread_cond_t sig1, sig2, sig3; |
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static pthread_mutex_t m1, m2, m3; |
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static pthread_mutex_t m1, m2, m3; |
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static pthread_barrier_t bar; |
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static volatile unsigned int done = 0; |
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static volatile unsigned int done = 0; |
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static unsigned int test_result = 0; |
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static void * |
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watchdog_tf (void *p) |
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{ |
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int err; |
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err = pthread_barrier_wait (&bar); |
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if (err != 0 && err != PTHREAD_BARRIER_SERIAL_THREAD) |
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error (EXIT_FAILURE, err, "watchdog_tf: barrier wait failed"); |
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/* Allow time for high_tf to set done=1 indicating a successful run. If |
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it is hung waiting on race_var, we set done=2 indicating failure. med_tf |
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will detect the 2 and indicate a failure in test_result. */ |
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usleep (1000); |
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if (done != 1) |
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{ |
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usleep (500000); |
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done = 2; |
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} |
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return NULL; |
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} |
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static void * |
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static void * |
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low_tf (void *p) |
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low_tf (void *p) |
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while (!done) |
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while (!done) |
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/* Busy wait to block low threads. */; |
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/* Busy wait to block low threads. */; |
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/* If watchdog_tf has set done to 2 before high_tf has set it to 1, |
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then the test has failed. */ |
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if (done == 2) |
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{ |
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puts ("med_tf: unbounded priority inversion detected."); |
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/* low_tf and high_tf are now waiting on race_var, having missed |
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the broadcast issued in do_test(). Wake them up now and exit |
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gracefully. */ |
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err = pthread_mutex_lock (&race_mut); |
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if (err != 0) |
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error (EXIT_FAILURE, err, "med_tf: failed to lock race_mut"); |
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err = pthread_cond_broadcast (&race_var); |
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if (err != 0) |
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error (EXIT_FAILURE, err, "med_tf: broadcast to race_var failed"); |
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err = pthread_mutex_unlock (&race_mut); |
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if (err != 0) |
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error (EXIT_FAILURE, err, "med_tf: failed to unlock race_mut"); |
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test_result = 1; |
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} |
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puts ("med_tf: done spinning"); |
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puts ("med_tf: done spinning"); |
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return NULL; |
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return NULL; |
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pthread_t low_thread; |
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pthread_t low_thread; |
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pthread_t med_thread; |
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pthread_t med_thread; |
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pthread_t high_thread; |
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pthread_t high_thread; |
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pthread_t watchdog_thread; |
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struct sched_param param; |
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struct sched_param param; |
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pthread_attr_t attr; |
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pthread_attr_t attr; |
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pthread_mutexattr_t m_attr; |
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pthread_mutexattr_t m_attr; |
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int err; |
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int err; |
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/* Initialize mutexes and condvars. */ |
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/* Initialize barrier, mutexes, and condvars. */ |
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err = pthread_barrier_init (&bar, NULL, 2); |
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if (err != 0) |
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error (EXIT_FAILURE, err, "parent: failed to init barrier"); |
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err = pthread_attr_init (&attr); |
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err = pthread_attr_init (&attr); |
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if (err != 0) |
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if (err != 0) |
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if (err != 0) |
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if (err != 0) |
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error (EXIT_FAILURE, err, "parent: failed to set CPU affinity"); |
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error (EXIT_FAILURE, err, "parent: failed to set CPU affinity"); |
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err = pthread_create (&watchdog_thread, &attr, watchdog_tf, (void*)NULL); |
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if (err != 0) |
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error (EXIT_FAILURE, err, "parent: failed to create watchdog_tf"); |
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param.sched_priority = LOW_PRIO; |
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param.sched_priority = LOW_PRIO; |
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err = pthread_attr_setschedparam (&attr, ¶m); |
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err = pthread_attr_setschedparam (&attr, ¶m); |
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if (err != 0) |
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if (err != 0) |
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PTHREAD_PRIO_INHERIT, low_tf will not have released the race_var cond_lock |
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PTHREAD_PRIO_INHERIT, low_tf will not have released the race_var cond_lock |
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and neither thread will have waited on race_var. */ |
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and neither thread will have waited on race_var. */ |
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usleep (1000); |
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usleep (1000); |
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err = pthread_barrier_wait (&bar); |
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if (err != 0 && err != PTHREAD_BARRIER_SERIAL_THREAD) |
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error (EXIT_FAILURE, err, "parent: barrier wait failed"); |
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err = pthread_cond_broadcast (&race_var); |
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err = pthread_cond_broadcast (&race_var); |
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if (err != 0) |
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if (err != 0) |
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error (EXIT_FAILURE, err, "parent: failed to broadcast condition"); |
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error (EXIT_FAILURE, err, "parent: failed to broadcast condition"); |
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/* Wait for threads to complete. */ |
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/* Wait for threads to complete. */ |
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err = pthread_join (watchdog_thread, (void**) NULL); |
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if (err != 0) |
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error (EXIT_FAILURE, err, "join of watchdog_tf failed"); |
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err = pthread_join (low_thread, (void**) NULL); |
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err = pthread_join (low_thread, (void**) NULL); |
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if (err != 0) |
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if (err != 0) |
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error (EXIT_FAILURE, err, "join of low_tf failed"); |
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error (EXIT_FAILURE, err, "join of low_tf failed"); |
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puts ("done"); |
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puts ("done"); |
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return 0; |
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return test_result; |
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} |
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} |
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