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//===-- sanitizer_stoptheworld_test.cpp -----------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Tests for sanitizer_stoptheworld.h
//
//===----------------------------------------------------------------------===//
#include "sanitizer_common/sanitizer_platform.h"
#if SANITIZER_LINUX && defined(__x86_64__)
#include "sanitizer_common/sanitizer_stoptheworld.h"
#include "gtest/gtest.h"
#include "sanitizer_common/sanitizer_libc.h"
#include "sanitizer_common/sanitizer_common.h"
#include <pthread.h>
#include <sched.h>
namespace __sanitizer {
static pthread_mutex_t incrementer_thread_exit_mutex;
struct CallbackArgument {
volatile int counter;
volatile bool threads_stopped;
volatile bool callback_executed;
CallbackArgument()
: counter(0),
threads_stopped(false),
callback_executed(false) {}
};
void *IncrementerThread(void *argument) {
CallbackArgument *callback_argument = (CallbackArgument *)argument;
while (true) {
__sync_fetch_and_add(&callback_argument->counter, 1);
if (pthread_mutex_trylock(&incrementer_thread_exit_mutex) == 0) {
pthread_mutex_unlock(&incrementer_thread_exit_mutex);
return NULL;
} else {
sched_yield();
}
}
}
// This callback checks that IncrementerThread is suspended at the time of its
// execution.
void Callback(const SuspendedThreadsList &suspended_threads_list,
void *argument) {
CallbackArgument *callback_argument = (CallbackArgument *)argument;
callback_argument->callback_executed = true;
int counter_at_init = __sync_fetch_and_add(&callback_argument->counter, 0);
for (uptr i = 0; i < 1000; i++) {
sched_yield();
if (__sync_fetch_and_add(&callback_argument->counter, 0) !=
counter_at_init) {
callback_argument->threads_stopped = false;
return;
}
}
callback_argument->threads_stopped = true;
}
TEST(StopTheWorld, SuspendThreadsSimple) {
pthread_mutex_init(&incrementer_thread_exit_mutex, NULL);
CallbackArgument argument;
pthread_t thread_id;
int pthread_create_result;
pthread_mutex_lock(&incrementer_thread_exit_mutex);
pthread_create_result = pthread_create(&thread_id, NULL, IncrementerThread,
&argument);
ASSERT_EQ(0, pthread_create_result);
StopTheWorld(&Callback, &argument);
pthread_mutex_unlock(&incrementer_thread_exit_mutex);
EXPECT_TRUE(argument.callback_executed);
EXPECT_TRUE(argument.threads_stopped);
// argument is on stack, so we have to wait for the incrementer thread to
// terminate before we can return from this function.
ASSERT_EQ(0, pthread_join(thread_id, NULL));
pthread_mutex_destroy(&incrementer_thread_exit_mutex);
}
// A more comprehensive test where we spawn a bunch of threads while executing
// StopTheWorld in parallel.
static const uptr kThreadCount = 50;
static const uptr kStopWorldAfter = 10; // let this many threads spawn first
static pthread_mutex_t advanced_incrementer_thread_exit_mutex;
struct AdvancedCallbackArgument {
volatile uptr thread_index;
volatile int counters[kThreadCount];
pthread_t thread_ids[kThreadCount];
volatile bool threads_stopped;
volatile bool callback_executed;
volatile bool fatal_error;
AdvancedCallbackArgument()
: thread_index(0),
threads_stopped(false),
callback_executed(false),
fatal_error(false) {}
};
void *AdvancedIncrementerThread(void *argument) {
AdvancedCallbackArgument *callback_argument =
(AdvancedCallbackArgument *)argument;
uptr this_thread_index = __sync_fetch_and_add(
&callback_argument->thread_index, 1);
// Spawn the next thread.
int pthread_create_result;
if (this_thread_index + 1 < kThreadCount) {
pthread_create_result =
pthread_create(&callback_argument->thread_ids[this_thread_index + 1],
NULL, AdvancedIncrementerThread, argument);
// Cannot use ASSERT_EQ in non-void-returning functions. If there's a
// problem, defer failing to the main thread.
if (pthread_create_result != 0) {
callback_argument->fatal_error = true;
__sync_fetch_and_add(&callback_argument->thread_index,
kThreadCount - callback_argument->thread_index);
}
}
// Do the actual work.
while (true) {
__sync_fetch_and_add(&callback_argument->counters[this_thread_index], 1);
if (pthread_mutex_trylock(&advanced_incrementer_thread_exit_mutex) == 0) {
pthread_mutex_unlock(&advanced_incrementer_thread_exit_mutex);
return NULL;
} else {
sched_yield();
}
}
}
void AdvancedCallback(const SuspendedThreadsList &suspended_threads_list,
void *argument) {
AdvancedCallbackArgument *callback_argument =
(AdvancedCallbackArgument *)argument;
callback_argument->callback_executed = true;
int counters_at_init[kThreadCount];
for (uptr j = 0; j < kThreadCount; j++)
counters_at_init[j] = __sync_fetch_and_add(&callback_argument->counters[j],
0);
for (uptr i = 0; i < 10; i++) {
sched_yield();
for (uptr j = 0; j < kThreadCount; j++)
if (__sync_fetch_and_add(&callback_argument->counters[j], 0) !=
counters_at_init[j]) {
callback_argument->threads_stopped = false;
return;
}
}
callback_argument->threads_stopped = true;
}
TEST(StopTheWorld, SuspendThreadsAdvanced) {
pthread_mutex_init(&advanced_incrementer_thread_exit_mutex, NULL);
AdvancedCallbackArgument argument;
pthread_mutex_lock(&advanced_incrementer_thread_exit_mutex);
int pthread_create_result;
pthread_create_result = pthread_create(&argument.thread_ids[0], NULL,
AdvancedIncrementerThread,
&argument);
ASSERT_EQ(0, pthread_create_result);
// Wait for several threads to spawn before proceeding.
while (__sync_fetch_and_add(&argument.thread_index, 0) < kStopWorldAfter)
sched_yield();
StopTheWorld(&AdvancedCallback, &argument);
EXPECT_TRUE(argument.callback_executed);
EXPECT_TRUE(argument.threads_stopped);
// Wait for all threads to spawn before we start terminating them.
while (__sync_fetch_and_add(&argument.thread_index, 0) < kThreadCount)
sched_yield();
ASSERT_FALSE(argument.fatal_error); // a pthread_create has failed
// Signal the threads to terminate.
pthread_mutex_unlock(&advanced_incrementer_thread_exit_mutex);
for (uptr i = 0; i < kThreadCount; i++)
ASSERT_EQ(0, pthread_join(argument.thread_ids[i], NULL));
pthread_mutex_destroy(&advanced_incrementer_thread_exit_mutex);
}
static void SegvCallback(const SuspendedThreadsList &suspended_threads_list,
void *argument) {
*(volatile int*)0x1234 = 0;
}
TEST(StopTheWorld, SegvInCallback) {
// Test that tracer thread catches SIGSEGV.
StopTheWorld(&SegvCallback, NULL);
}
} // namespace __sanitizer
#endif // SANITIZER_LINUX && defined(__x86_64__)
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