Test hangs with TSAN #5117
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This was referenced Mar 16, 2023
Merged
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As far as I found, google/sanitizers#498 is the most closest problem in terms of that pthread_cond_wait is releated. But it's very old so I am not sure it's the same problem |
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It reproduces with a small c++ code outside CCF takurosato@takurosato-virtual2:~/misc/tsan$ cat main.cpp
#include <iostream>
#include <thread>
#include <algorithm>
#include <vector>
#include <mutex>
#include <memory>
#include <atomic>
#include <condition_variable>
namespace threading
{
using ThreadID = uint16_t;
static constexpr ThreadID MAIN_THREAD_ID = 0;
static std::atomic<ThreadID> next_thread_id = MAIN_THREAD_ID;
uint16_t get_current_thread_id()
{
thread_local ThreadID this_thread_id = next_thread_id.fetch_add(1);
return this_thread_id;
}
void reset_thread_id_generator()
{
next_thread_id.store(MAIN_THREAD_ID);
}
}
int main() {
std::mutex assigned_ids_lock;
std::vector<uint16_t> assigned_ids;
const auto main_thread_id = threading::get_current_thread_id();
// REQUIRE(main_thread_id == threading::MAIN_THREAD_ID);
assigned_ids.push_back(main_thread_id);
std::mutex all_done_lock;
std::condition_variable all_done;
auto fn = [&]() {
{
std::lock_guard<std::mutex> guard(assigned_ids_lock);
const auto current_thread_id = threading::get_current_thread_id();
assigned_ids.push_back(current_thread_id);
}
{
std::unique_lock lock(all_done_lock);
all_done.wait(lock);
}
};
constexpr size_t num_threads = 20;
constexpr size_t expected_ids = num_threads + 1; // Includes MAIN_THREAD_ID
std::vector<std::thread> threads;
for (auto i = 0; i < num_threads; ++i)
{
threads.emplace_back(fn);
}
size_t attempts = 0;
constexpr size_t max_attempts = 5;
while (true)
{
{
std::lock_guard<std::mutex> guard(assigned_ids_lock);
if (assigned_ids.size() == expected_ids)
{
all_done.notify_all();
break;
}
}
// REQUIRE(++attempts < max_attempts);
std::this_thread::sleep_for(std::chrono::milliseconds(50));
}
// REQUIRE(assigned_ids.size() == expected_ids);
for (auto& thread : threads)
{
thread.join();
}
const auto unique = std::unique(assigned_ids.begin(), assigned_ids.end());
// REQUIRE_MESSAGE(
// unique == assigned_ids.end(),
// fmt::format(
// "Thread IDs are not unique: {}", fmt::join(assigned_ids, ", ")));
}
takurosato@takurosato-virtual2:~/misc/tsan$ cat run.sh
#!/bin/bash
clang++-15 -g -pthread -stdlib=libc++ -fsanitize=thread -std=c++20 main.cpp && ./a.out |
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part of #4994
It happens in
Virtual MultiThreadTsanCIhttps://dev.azure.com/MSRC-CCF/CCF/_build/results?buildId=67000&view=logs&j=7944d106-e7da-5d45-12ec-6dfc8e3f5a03&t=564afb6e-c35d-5add-8e9b-52387eab437a
Reproduce
Also you can reproduce it locally.
Note that the tests you see this bug are different depending of clang version.
If you use clang-12, you don't see this in
ds_test, but still do ine2e_logging_cftetc.In which test cases does it happen?
ds_test and many E2E tests.
Smallest test to reproduce it.
ds_test is the handy one to reproduce.
Looks like it happens in "Unique thread IDs" test case in thread_messaging.cpp. The ds_test passes without it.
In other terminal,
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