ASSERT(0);
}
+#include <signal.h>
+
+#define SIGSTACKSIZE 65536
+static void mprot_handle_pf(int sig, siginfo_t *si, void *unused)
+{
+ model_print("Segmentation fault at %p\n", si->si_addr);
+ model_print("For debugging, place breakpoint at: %s:%d\n",
+ __FILE__, __LINE__);
+ print_trace(); // Trace printing may cause dynamic memory allocation
+ while(1)
+ ;
+}
+
+void install_handler() {
+ stack_t ss;
+ ss.ss_sp = model_malloc(SIGSTACKSIZE);
+ ss.ss_size = SIGSTACKSIZE;
+ ss.ss_flags = 0;
+ sigaltstack(&ss, NULL);
+ struct sigaction sa;
+ sa.sa_flags = SA_SIGINFO | SA_NODEFER | SA_RESTART | SA_ONSTACK;
+ sigemptyset(&sa.sa_mask);
+ sa.sa_sigaction = mprot_handle_pf;
+
+ if (sigaction(SIGSEGV, &sa, NULL) == -1) {
+ perror("sigaction(SIGSEGV)");
+ exit(EXIT_FAILURE);
+ }
+}
+
+void createModelIfNotExist() {
+ if (!model) {
+ snapshot_system_init(100000);
+ model = new ModelChecker();
+ model->startChecker();
+ }
+}
+
/** @brief Constructor */
ModelChecker::ModelChecker() :
/* Initialize default scheduler */
history(new ModelHistory()),
execution(new ModelExecution(this, scheduler)),
execution_number(1),
+ curr_thread_num(1),
trace_analyses(),
inspect_plugin(NULL)
{
parse_options(¶ms);
initRaceDetector();
/* Configure output redirection for the model-checker */
- redirect_output();
- install_trace_analyses(get_execution());
+ install_handler();
}
/** @brief Destructor */
return scheduler->get_current_thread();
}
+/**
+ * Must be called from user-thread context (e.g., through the global
+ * thread_current_id() interface)
+ *
+ * @return The id of the currently executing Thread.
+ */
+thread_id_t ModelChecker::get_current_thread_id() const
+{
+ ASSERT(int_to_id(curr_thread_num) == get_current_thread()->get_id());
+ return int_to_id(curr_thread_num);
+}
+
/**
* @brief Choose the next thread to execute.
*
{
/* If feasible bug, bail out now */
assert_bug(msg);
- switch_to_master(NULL);
+ switch_thread(NULL);
}
/** @brief Print bug report listing for this execution (if any bugs exist) */
else
clear_program_output();
-// test code
execution_number ++;
+ history->set_new_exec_flag();
+
if (more_executions)
reset_to_initial_state();
- history->set_new_exec_flag();
}
/** @brief Run trace analyses on complete trace */
return execution->get_thread(act);
}
-/**
- * Switch from a model-checker context to a user-thread context. This is the
- * complement of ModelChecker::switch_to_master and must be called from the
- * model-checker context
- *
- * @param thread The user-thread to switch to
- */
-void ModelChecker::switch_from_master(Thread *thread)
+void ModelChecker::startRunExecution(Thread *old) {
+ while (true) {
+ if (params.traceminsize != 0 &&
+ execution->get_curr_seq_num() > checkfree) {
+ checkfree += params.checkthreshold;
+ execution->collectActions();
+ }
+
+ curr_thread_num = 1;
+ Thread *thr = getNextThread(old);
+ if (thr != nullptr) {
+ scheduler->set_current_thread(thr);
+
+ if (Thread::swap(old, thr) < 0) {
+ perror("swap threads");
+ exit(EXIT_FAILURE);
+ }
+ return;
+ }
+
+ if (!handleChosenThread(old)) {
+ return;
+ }
+ }
+}
+
+Thread* ModelChecker::getNextThread(Thread *old)
{
- scheduler->set_current_thread(thread);
- Thread::swap(&system_context, thread);
+ Thread *nextThread = nullptr;
+ for (unsigned int i = curr_thread_num;i < get_num_threads();i++) {
+ thread_id_t tid = int_to_id(i);
+ Thread *thr = get_thread(tid);
+
+ if (!thr->is_complete()) {
+ if (!thr->get_pending()) {
+ curr_thread_num = i;
+ nextThread = thr;
+ break;
+ }
+ } else if (thr != old && !thr->is_freed()) {
+ thr->freeResources();
+ }
+
+ ModelAction *act = thr->get_pending();
+ if (act && execution->is_enabled(tid)){
+ /* Don't schedule threads which should be disabled */
+ if (!execution->check_action_enabled(act)) {
+ scheduler->sleep(thr);
+ }
+
+ /* Allow pending relaxed/release stores or thread actions to perform first */
+ else if (!chosen_thread) {
+ if (act->is_write()) {
+ std::memory_order order = act->get_mo();
+ if (order == std::memory_order_relaxed || \
+ order == std::memory_order_release) {
+ chosen_thread = thr;
+ }
+ } else if (act->get_type() == THREAD_CREATE || \
+ act->get_type() == PTHREAD_CREATE || \
+ act->get_type() == THREAD_START || \
+ act->get_type() == THREAD_FINISH) {
+ chosen_thread = thr;
+ }
+ }
+ }
+ }
+ return nextThread;
}
-/**
- * Switch from a user-context to the "master thread" context (a.k.a. system
- * context). This switch is made with the intention of exploring a particular
- * model-checking action (described by a ModelAction object). Must be called
- * from a user-thread context.
- *
- * @param act The current action that will be explored. May be NULL only if
- * trace is exiting via an assertion (see ModelExecution::set_assert and
- * ModelExecution::has_asserted).
- * @return Return the value returned by the current action
- */
-uint64_t ModelChecker::switch_to_master(ModelAction *act)
+/* Swap back to system_context and terminate this execution */
+void ModelChecker::finishRunExecution(Thread *old)
+{
+ scheduler->set_current_thread(NULL);
+
+ /** Reset curr_thread_num to initial value for next execution. */
+ curr_thread_num = 1;
+
+ /** If we have more executions, we won't make it past this call. */
+ finish_execution(execution_number < params.maxexecutions);
+
+
+ /** We finished the final execution. Print stuff and exit. */
+ model_print("******* Model-checking complete: *******\n");
+ print_stats();
+
+ /* Have the trace analyses dump their output. */
+ for (unsigned int i = 0;i < trace_analyses.size();i++)
+ trace_analyses[i]->finish();
+
+ /* unlink tmp file created by last child process */
+ char filename[256];
+ snprintf_(filename, sizeof(filename), "C11FuzzerTmp%d", getpid());
+ unlink(filename);
+
+ /* Exit. */
+ _Exit(0);
+}
+
+uint64_t ModelChecker::switch_thread(ModelAction *act)
{
if (modellock) {
static bool fork_message_printed = false;
}
DBG();
Thread *old = thread_current();
- scheduler->set_current_thread(NULL);
+ old->set_state(THREAD_READY);
+
ASSERT(!old->get_pending());
if (inspect_plugin != NULL) {
}
old->set_pending(act);
- if (Thread::swap(old, &system_context) < 0) {
- perror("swap threads");
- exit(EXIT_FAILURE);
+
+ if (old->is_waiting_on(old))
+ assert_bug("Deadlock detected (thread %u)", curr_thread_num);
+
+ Thread* next = getNextThread(old);
+ if (next != nullptr) {
+ scheduler->set_current_thread(next);
+ if (Thread::swap(old, next) < 0) {
+ perror("swap threads");
+ exit(EXIT_FAILURE);
+ }
+ } else {
+ if (handleChosenThread(old)) {
+ startRunExecution(old);
+ }
}
return old->get_return_value();
}
-static void runChecker() {
- model->run();
- delete model;
+bool ModelChecker::handleChosenThread(Thread *old)
+{
+ if (execution->has_asserted()) {
+ finishRunExecution(old);
+ return false;
+ }
+ if (!chosen_thread) {
+ chosen_thread = get_next_thread();
+ }
+ if (!chosen_thread) {
+ finishRunExecution(old);
+ return false;
+ }
+ if (chosen_thread->just_woken_up()) {
+ chosen_thread->set_wakeup_state(false);
+ chosen_thread->set_pending(NULL);
+ chosen_thread = NULL;
+ // Allow this thread to stash the next pending action
+ return true;
+ }
+
+ // Consume the next action for a Thread
+ ModelAction *curr = chosen_thread->get_pending();
+ chosen_thread->set_pending(NULL);
+ chosen_thread = execution->take_step(curr);
+
+ if (should_terminate_execution()) {
+ finishRunExecution(old);
+ return false;
+ } else {
+ return true;
+ }
}
void ModelChecker::startChecker() {
- startExecution(get_system_context(), runChecker);
+ startExecution();
+ //Need to initial random number generator state to avoid resets on rollback
+ initstate(423121, random_state, sizeof(random_state));
+
snapshot = take_snapshot();
+
+ //reset random number generator state
+ setstate(random_state);
+
+ install_trace_analyses(get_execution());
+ redirect_output();
initMainThread();
}
}
return false;
}
-
-/** @brief Run ModelChecker for the user program */
-void ModelChecker::run()
-{
- //Need to initial random number generator state to avoid resets on rollback
- char random_state[256];
- initstate(423121, random_state, sizeof(random_state));
- modelclock_t checkfree = params.checkthreshold;
- for(int exec = 0;exec < params.maxexecutions;exec++) {
- Thread * t = init_thread;
-
- do {
- /* Check whether we need to free model actions. */
-
- if (params.traceminsize != 0 &&
- execution->get_curr_seq_num() > checkfree) {
- checkfree += params.checkthreshold;
- execution->collectActions();
- }
-
- /*
- * Stash next pending action(s) for thread(s). There
- * should only need to stash one thread's action--the
- * thread which just took a step--plus the first step
- * for any newly-created thread
- */
- for (unsigned int i = 0;i < get_num_threads();i++) {
- thread_id_t tid = int_to_id(i);
- Thread *thr = get_thread(tid);
- if (!thr->is_model_thread() && !thr->is_complete() && !thr->get_pending()) {
- switch_from_master(thr);
- if (thr->is_waiting_on(thr))
- assert_bug("Deadlock detected (thread %u)", i);
- }
- }
-
- /* Don't schedule threads which should be disabled */
- for (unsigned int i = 0;i < get_num_threads();i++) {
- Thread *th = get_thread(int_to_id(i));
- ModelAction *act = th->get_pending();
- if (act && execution->is_enabled(th) && !execution->check_action_enabled(act)) {
- scheduler->sleep(th);
- }
- }
-
- for (unsigned int i = 1;i < get_num_threads();i++) {
- Thread *th = get_thread(int_to_id(i));
- ModelAction *act = th->get_pending();
- if (act && execution->is_enabled(th) && (th->get_state() != THREAD_BLOCKED) ) {
- if (act->is_write()) {
- std::memory_order order = act->get_mo();
- if (order == std::memory_order_relaxed || \
- order == std::memory_order_release) {
- t = th;
- break;
- }
- } else if (act->get_type() == THREAD_CREATE || \
- act->get_type() == PTHREAD_CREATE || \
- act->get_type() == THREAD_START || \
- act->get_type() == THREAD_FINISH) {
- t = th;
- break;
- }
- }
- }
-
- /* Catch assertions from prior take_step or from
- * between-ModelAction bugs (e.g., data races) */
-
- if (execution->has_asserted())
- break;
- if (!t)
- t = get_next_thread();
- if (!t || t->is_model_thread())
- break;
- if (t->just_woken_up()) {
- t->set_wakeup_state(false);
- t->set_pending(NULL);
- t = NULL;
- continue; // Allow this thread to stash the next pending action
- }
-
- /* Consume the next action for a Thread */
- ModelAction *curr = t->get_pending();
- t->set_pending(NULL);
- t = execution->take_step(curr);
- } while (!should_terminate_execution());
- finish_execution((exec+1) < params.maxexecutions);
- //restore random number generator state after rollback
- setstate(random_state);
- }
-
- model_print("******* Model-checking complete: *******\n");
- print_stats();
-
- /* Have the trace analyses dump their output. */
- for (unsigned int i = 0;i < trace_analyses.size();i++)
- trace_analyses[i]->finish();
-
- /* unlink tmp file created by last child process */
- char filename[256];
- snprintf_(filename, sizeof(filename), "C11FuzzerTmp%d", getpid());
- unlink(filename);
-}
projects / c11tester.git / blobdiff