return node_stack->get_head();
}
+/**
+ * @brief Select the next thread to execute based on the curren action
+ *
+ * RMW actions occur in two parts, and we cannot split them. And THREAD_CREATE
+ * actions should be followed by the execution of their child thread. In either
+ * case, the current action should determine the next thread schedule.
+ *
+ * @param curr The current action
+ * @return The next thread to run, if the current action will determine this
+ * selection; otherwise NULL
+ */
+Thread * ModelChecker::action_select_next_thread(const ModelAction *curr) const
+{
+ /* Do not split atomic RMW */
+ if (curr->is_rmwr())
+ return get_thread(curr);
+ /* Follow CREATE with the created thread */
+ if (curr->get_type() == THREAD_CREATE)
+ return curr->get_thread_operand();
+ return NULL;
+}
+
/**
* @brief Choose the next thread to execute.
*
- * This function chooses the next thread that should execute. It can force the
- * adjacency of read/write portions of a RMW action, force THREAD_CREATE to be
- * followed by a THREAD_START, or it can enforce execution replay/backtracking.
- * The model-checker may have no preference regarding the next thread (i.e.,
- * when exploring a new execution ordering), in which case we defer to the
- * scheduler.
+ * This function chooses the next thread that should execute. It can enforce
+ * execution replay/backtracking or, if the model-checker has no preference
+ * regarding the next thread (i.e., when exploring a new execution ordering),
+ * we defer to the scheduler.
*
- * @param curr Optional: The current ModelAction. Only used if non-NULL and it
- * might guide the choice of next thread (i.e., THREAD_CREATE should be
- * followed by THREAD_START, or ATOMIC_RMWR followed by ATOMIC_{RMW,RMWC})
- * @return The next chosen thread to run, if any exist. Or else if no threads
- * remain to be executed, return NULL.
+ * @return The next chosen thread to run, if any exist. Or else if the current
+ * execution should terminate, return NULL.
*/
-Thread * ModelChecker::get_next_thread(ModelAction *curr)
+Thread * ModelChecker::get_next_thread()
{
thread_id_t tid;
- if (curr != NULL) {
- /* Do not split atomic actions. */
- if (curr->is_rmwr())
- return get_thread(curr);
- else if (curr->get_type() == THREAD_CREATE)
- return curr->get_thread_operand();
- }
-
/*
* Have we completed exploring the preselected path? Then let the
* scheduler decide
return blocking_threads;
}
+/**
+ * Check if a Thread has entered a circular wait deadlock situation. This will
+ * not check other threads for potential deadlock situations, and may miss
+ * deadlocks involving WAIT.
+ *
+ * @param t The thread which may have entered a deadlock
+ * @return True if this Thread entered a deadlock; false otherwise
+ */
+bool ModelChecker::is_circular_wait(const Thread *t) const
+{
+ for (Thread *waiting = t->waiting_on() ; waiting != NULL; waiting = waiting->waiting_on())
+ if (waiting == t)
+ return true;
+ return false;
+}
+
/**
* Check if this is a complete execution. That is, have all thread completed
* execution (rather than exiting because sleep sets have forced a redundant
{
print_program_output();
- if (DBG_ENABLED() || params.verbose) {
+ if (params.verbose) {
model_print("Earliest divergence point since last feasible execution:\n");
if (earliest_diverge)
earliest_diverge->print();
record_stats();
/* Output */
- if (DBG_ENABLED() || params.verbose || (complete && have_bug_reports()))
+ if (params.verbose || (complete && have_bug_reports()))
print_execution(complete);
else
clear_program_output();
bool ModelChecker::process_read(ModelAction *curr)
{
Node *node = curr->get_node();
- uint64_t value = VALUE_NONE;
while (true) {
bool updated = false;
switch (node->get_read_from_status()) {
}
updated = r_modification_order(curr, rf);
- value = rf->get_value();
read_from(curr, rf);
mo_graph->commitChanges();
mo_check_promises(curr, true);
}
case READ_FROM_PROMISE: {
Promise *promise = curr->get_node()->get_read_from_promise();
- promise->add_reader(curr);
- value = promise->get_value();
+ if (promise->add_reader(curr))
+ priv->failed_promise = true;
curr->set_read_from_promise(promise);
mo_graph->startChanges();
if (!check_recency(curr, promise))
/* Read from future value */
struct future_value fv = node->get_future_value();
Promise *promise = new Promise(curr, fv);
- value = fv.value;
curr->set_read_from_promise(promise);
promises->push_back(promise);
mo_graph->startChanges();
default:
ASSERT(false);
}
- get_thread(curr)->set_return_value(value);
+ get_thread(curr)->set_return_value(curr->get_return_value());
return updated;
}
}
*/
bool ModelChecker::process_mutex(ModelAction *curr)
{
- std::mutex *mutex = NULL;
+ std::mutex *mutex = curr->get_mutex();
struct std::mutex_state *state = NULL;
- if (curr->is_trylock() || curr->is_lock() || curr->is_unlock()) {
- mutex = (std::mutex *)curr->get_location();
+ if (mutex)
state = mutex->get_state();
- } else if (curr->is_wait()) {
- mutex = (std::mutex *)curr->get_value();
- state = mutex->get_state();
- }
switch (curr->get_type()) {
case ATOMIC_TRYLOCK: {
- bool success = !state->islocked;
+ bool success = !state->locked;
curr->set_try_lock(success);
if (!success) {
get_thread(curr)->set_return_value(0);
case ATOMIC_LOCK: {
if (curr->get_cv()->getClock(state->alloc_tid) <= state->alloc_clock)
assert_bug("Lock access before initialization");
- state->islocked = true;
+ state->locked = get_thread(curr);
ModelAction *unlock = get_last_unlock(curr);
//synchronize with the previous unlock statement
if (unlock != NULL) {
}
case ATOMIC_UNLOCK: {
//unlock the lock
- state->islocked = false;
+ state->locked = NULL;
//wake up the other threads
action_list_t *waiters = get_safe_ptr_action(lock_waiters_map, curr->get_location());
//activate all the waiting threads
}
case ATOMIC_WAIT: {
//unlock the lock
- state->islocked = false;
+ state->locked = NULL;
//wake up the other threads
action_list_t *waiters = get_safe_ptr_action(lock_waiters_map, (void *) curr->get_value());
//activate all the waiting threads
if (curr->is_lock()) {
std::mutex *lock = (std::mutex *)curr->get_location();
struct std::mutex_state *state = lock->get_state();
- if (state->islocked) {
+ if (state->locked) {
//Stick the action in the appropriate waiting queue
get_safe_ptr_action(lock_waiters_map, curr->get_location())->push_back(curr);
return false;
unsigned int hash = 0;
for (it = list->begin(); it != list->end(); it++) {
- (*it)->print();
+ const ModelAction *act = *it;
+ if (act->get_seq_number() > 0)
+ act->print();
hash = hash^(hash<<3)^((*it)->hash());
}
model_print("HASH %u\n", hash);
print_infeasibility(" INFEASIBLE");
print_list(action_trace);
model_print("\n");
+ if (!promises->empty()) {
+ model_print("Pending promises:\n");
+ for (unsigned int i = 0; i < promises->size(); i++) {
+ model_print(" [P%u] ", i);
+ (*promises)[i]->print();
+ }
+ model_print("\n");
+ }
}
/**
if (curr_thrd->is_blocked() || curr_thrd->is_complete())
scheduler->remove_thread(curr_thrd);
- Thread *next_thrd = get_next_thread(curr);
+ Thread *next_thrd = NULL;
+ if (curr)
+ next_thrd = action_select_next_thread(curr);
+ if (!next_thrd)
+ next_thrd = get_next_thread();
DEBUG("(%d, %d)\n", curr_thrd ? id_to_int(curr_thrd->get_id()) : -1,
next_thrd ? id_to_int(next_thrd->get_id()) : -1);
Thread *thr = get_thread(tid);
if (!thr->is_model_thread() && !thr->is_complete() && !thr->get_pending()) {
switch_from_master(thr);
+ if (is_circular_wait(thr))
+ assert_bug("Deadlock detected");
}
}
projects / c11tester.git / blobdiff