C++ catch块内执行Boost yield引发线程崩溃问题排查

正在排查C++环境下，因在catch块内执行Boost yield操作导致的线程崩溃场景，以下是稳定复现崩溃的核心信息：

• 必须使用thread_group中的多线程才能触发崩溃
• 需同时运行2个协程（coroutine）
• 在catch块外执行yield时功能完全正常
• 该问题可在Mac/Win平台稳定复现（Linux未测试）
• 调试时崩溃调用栈指向catch块内的yield操作
• 曾找到提及类似问题的旧论坛讨论，但对其解释理解不清

稳定复现代码 #

链接Boost 1.83-1.86版本即可直接运行：

#include <boost/asio.hpp>
#include <boost/asio/spawn.hpp>
#include <boost/thread.hpp>
#include <iostream>

namespace asio = boost::asio;
using namespace std::chrono_literals;

void TimerCatchYield(asio::steady_timer& timer,
                     const asio::yield_context& yield) {
  boost::system::error_code ec;
  try {
    throw std::runtime_error("");
  } catch (const std::exception&) {
    // async_wait(yield) here - causes crash
    timer.async_wait(yield[ec]);
  }
  // async_wait(yield) here - works as expected
}

void coroutineA(asio::steady_timer& timer, const asio::yield_context& yield) {
  std::cout << "Coroutine A: Starting timer...\n";

  timer.expires_after(500ms);
  TimerCatchYield(timer, yield);
  std::cout << "Coroutine A: 1\n";

  timer.expires_after(500ms);
  TimerCatchYield(timer, yield);
  std::cout << "Coroutine A: 2\n";

  timer.expires_after(500ms);
  TimerCatchYield(timer, yield);
  std::cout << "Coroutine A: 3\n";

  std::cout << "Coroutine A: all timers expired\n";
}

void coroutineB(asio::steady_timer& timer, const asio::yield_context& yield) {
  std::cout << "Coroutine B: Starting timer...\n";
  boost::system::error_code ec;

  timer.expires_after(500ms);
  timer.async_wait(yield[ec]);
  std::cout << "Coroutine B: 1\n";

  timer.expires_after(500ms);
  timer.async_wait(yield[ec]);
  std::cout << "Coroutine B: 2\n";

  timer.expires_after(500ms);
  timer.async_wait(yield[ec]);
  std::cout << "Coroutine B: 3\n";

  std::cout << "Coroutine B: all timers expired\n";
}

int main() {
  asio::io_context io;
  asio::steady_timer timerA(io);
  asio::steady_timer timerB(io);

  auto strand = make_strand(io);

  boost::thread_group threads;

  spawn(strand,
        [&](const asio::yield_context& yield) { coroutineA(timerA, yield); });

  spawn(strand, [&](const asio::yield_context& yield_b) {
    coroutineB(timerB, yield_b);
  });

  for (int i = 0; i < 4; ++i) {
    threads.create_thread([&io]() { io.run(); });
  }

  threads.join_all();

  std::cout << "Main finished\n";
  return 0;
}

内容的提问来源于stack exchange，提问作者Zohar81