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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_stoptheworld.h"
#include "sanitizer_common/sanitizer_platform.h"
#if (SANITIZER_LINUX || SANITIZER_WINDOWS) && defined(__x86_64__)
# include <atomic>
# include <mutex>
# include <thread>
# include "gtest/gtest.h"
# include "sanitizer_common/sanitizer_common.h"
# include "sanitizer_common/sanitizer_libc.h"
namespace __sanitizer {
static std::mutex mutex;
struct CallbackArgument {
std::atomic_int counter = {};
std::atomic_bool threads_stopped = {};
std::atomic_bool callback_executed = {};
};
void IncrementerThread(CallbackArgument &callback_argument) {
while (true) {
callback_argument.counter++;
if (mutex.try_lock()) {
mutex.unlock();
return;
}
std::this_thread::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 = callback_argument->counter;
for (uptr i = 0; i < 1000; i++) {
std::this_thread::yield();
if (callback_argument->counter != counter_at_init) {
callback_argument->threads_stopped = false;
return;
}
}
callback_argument->threads_stopped = true;
}
TEST(StopTheWorld, SuspendThreadsSimple) {
CallbackArgument argument;
std::thread thread;
{
std::lock_guard<std::mutex> lock(mutex);
thread = std::thread(IncrementerThread, std::ref(argument));
StopTheWorld(&Callback, &argument);
}
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_NO_THROW(thread.join());
}
// 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
struct AdvancedCallbackArgument {
std::atomic_uintptr_t thread_index = {};
std::atomic_int counters[kThreadCount] = {};
std::thread threads[kThreadCount];
std::atomic_bool threads_stopped = {};
std::atomic_bool callback_executed = {};
};
void AdvancedIncrementerThread(AdvancedCallbackArgument &callback_argument) {
uptr this_thread_index = callback_argument.thread_index++;
// Spawn the next thread.
if (this_thread_index + 1 < kThreadCount) {
callback_argument.threads[this_thread_index + 1] =
std::thread(AdvancedIncrementerThread, std::ref(callback_argument));
}
// Do the actual work.
while (true) {
callback_argument.counters[this_thread_index]++;
if (mutex.try_lock()) {
mutex.unlock();
return;
}
std::this_thread::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] = callback_argument->counters[j];
for (uptr i = 0; i < 10; i++) {
std::this_thread::yield();
for (uptr j = 0; j < kThreadCount; j++)
if (callback_argument->counters[j] != counters_at_init[j]) {
callback_argument->threads_stopped = false;
return;
}
}
callback_argument->threads_stopped = true;
}
TEST(StopTheWorld, SuspendThreadsAdvanced) {
AdvancedCallbackArgument argument;
{
std::lock_guard<std::mutex> lock(mutex);
argument.threads[0] =
std::thread(AdvancedIncrementerThread, std::ref(argument));
// Wait for several threads to spawn before proceeding.
while (argument.thread_index < kStopWorldAfter) std::this_thread::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 (argument.thread_index < kThreadCount) std::this_thread::yield();
}
// Signal the threads to terminate.
for (auto &t : argument.threads) t.join();
}
static void SegvCallback(const SuspendedThreadsList &suspended_threads_list,
void *argument) {
*(volatile int *)0x1234 = 0;
}
# if SANITIZER_WINDOWS
# define MAYBE_SegvInCallback DISABLED_SegvInCallback
# else
# define MAYBE_SegvInCallback SegvInCallback
# endif
TEST(StopTheWorld, MAYBE_SegvInCallback) {
// Test that tracer thread catches SIGSEGV.
StopTheWorld(&SegvCallback, NULL);
}
} // namespace __sanitizer
#endif // SANITIZER_LINUX && defined(__x86_64__)
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