[Boost-users] TSan error with boost::interprocess::message_queue on macOS ARM

Hello List, I'm using the boost::interprocess::message_queue in a project and to verify everything is working I created a test case. In that test case I'm sending and receiving data via threads. The test passes on Linux, Windows with no sanitizer and also with AddressSanitizer and ThreadSanitizer. I recently added Apple Silicon (M1) to the test matrix and now the test run with ThreadSanitizer enabled fails. Is boost::interprocess::message_queue thread-safe? Can the reported TSan error be an false-positive? If it that case, what test can I run to verify that? I looked at code of atomic_cas32() and it uses the legacy built-in __sync_val_compare_and_swap(). Can it be that that built-in isn't supported on ARM? Is there a newer built-in which should be used? The reported TSan error: -- snip ================== WARNING: ThreadSanitizer: data race (pid=4146) Atomic write of size 4 at 0x000104af4028 by thread T2: #0 __tsan_atomic32_compare_exchange_val <null>:81245684 (libclang_rt.tsan_osx_dynamic.dylib:arm64e+0x57854) #1 boost::interprocess::ipcdetail::atomic_cas32(unsigned int volatile*, unsigned int, unsigned int) atomic.hpp:581 (tsan_boost:arm64+0x100005b30) Previous read of size 4 at 0x000104af4028 by thread T1: #0 boost::interprocess::ipcdetail::spin_mutex::try_lock() mutex.hpp:100 (tsan_boost:arm64+0x100006eb0) #1 void boost::interprocess::ipcdetail::try_based_lockboost::interprocess::ipcdetail::spin_mutex(boost::interprocess::ipcdetail::spin_mutex&) common_algorithms.hpp:62 (tsan_boost:arm64+0x100006e28) SUMMARY: ThreadSanitizer: data race atomic.hpp:581 in boost::interprocess::ipcdetail::atomic_cas32(unsigned int volatile*, unsigned int, unsigned int) -- snap Here is a code example which demonstrates the test case -- snip #include #include <iostream> #include <vector> #include <thread> #include <memory> struct MessageQueueImpl { MessageQueueImpl() { boost::interprocess::permissions file_permissions; file_permissions.set_permissions(0660); queue = std::make_uniqueboost::interprocess::message_queue(boost::interprocess::create_only, "tsanqueue", 10, 15, file_permissions); } std::unique_ptrboost::interprocess::message_queue queue; }; class MessageQueue { public: MessageQueue() : m_impl(std::make_unique<MessageQueueImpl>()) {} void send(const std::vector& buffer) { m_impl->queue->send(buffer.data(), buffer.size(), 0); } void receive(std::vector& buffer) { boost::interprocess::message_queue::size_type received_size = 0; buffer.resize(m_impl->queue->get_max_msg_size()); uint32_t prio; m_impl->queue->receive(buffer.data(), buffer.size(), received_size, prio); buffer.resize(received_size); } private: std::unique_ptr<MessageQueueImpl> m_impl; }; int main() { auto uut = std::make_unique<MessageQueue>(); std::thread sender([&uut]{ for(uint8_t i = 0; i < 3; ++i) { const std::vector send_buffer = {i}; uut->send(send_buffer); } }); std::thread receiver([&uut]{ for(uint8_t i = 0; i < 3; ++i) { std::vector receive_buffer; uint32_t prio; uut->receive(receive_buffer); std::cout << "buffer received:\n"; for (const auto i : receive_buffer) { std::cout << i << '\n'; } } }); if(sender.joinable()) { sender.join(); } if(receiver.joinable()) { receiver.join(); } return 0; } -- snap Cheers, Jens