diff --git a/Lib/asyncio/unix_events.py b/Lib/asyncio/unix_events.py index 7623f789d31..b4e269924d5 100644 --- a/Lib/asyncio/unix_events.py +++ b/Lib/asyncio/unix_events.py @@ -167,23 +167,25 @@ class SelectorEventLoop(selector_events.BaseSelectorEventLoop): def _sig_chld(self): try: - try: - pid, status = os.waitpid(-1, os.WNOHANG) - except ChildProcessError: - return - if pid == 0: - self.call_soon(self._sig_chld) - return - elif os.WIFSIGNALED(status): - returncode = -os.WTERMSIG(status) - elif os.WIFEXITED(status): - returncode = os.WEXITSTATUS(status) - else: - self.call_soon(self._sig_chld) - return - transp = self._subprocesses.get(pid) - if transp is not None: - transp._process_exited(returncode) + # because of signal coalescing, we must keep calling waitpid() as + # long as we're able to reap a child + while True: + try: + pid, status = os.waitpid(-1, os.WNOHANG) + except ChildProcessError: + break + if pid == 0: + break + elif os.WIFSIGNALED(status): + returncode = -os.WTERMSIG(status) + elif os.WIFEXITED(status): + returncode = os.WEXITSTATUS(status) + else: + # shouldn't happen + continue + transp = self._subprocesses.get(pid) + if transp is not None: + transp._process_exited(returncode) except Exception: logger.exception('Unknown exception in SIGCHLD handler')