From e76ee1a72b9e3f5da287663ea3daec4bb3f67612 Mon Sep 17 00:00:00 2001 From: Victor Stinner Date: Fri, 6 Dec 2019 16:32:41 +0100 Subject: bpo-38982: Fix asyncio PidfdChildWatcher on waitpid() error (GH-17477) If waitpid() is called elsewhere, waitpid() call fails with ChildProcessError: use return code 255 in this case, and log a warning. It ensure that the pidfd file descriptor is closed if this error occurs. --- Lib/asyncio/unix_events.py | 15 +++++++++++++-- .../next/Library/2019-12-05-18-21-26.bpo-38982.W3u-03.rst | 5 +++++ 2 files changed, 18 insertions(+), 2 deletions(-) create mode 100644 Misc/NEWS.d/next/Library/2019-12-05-18-21-26.bpo-38982.W3u-03.rst diff --git a/Lib/asyncio/unix_events.py b/Lib/asyncio/unix_events.py index 97198ea..28fb491 100644 --- a/Lib/asyncio/unix_events.py +++ b/Lib/asyncio/unix_events.py @@ -930,9 +930,20 @@ class PidfdChildWatcher(AbstractChildWatcher): def _do_wait(self, pid): pidfd, callback, args = self._callbacks.pop(pid) self._loop._remove_reader(pidfd) - _, status = os.waitpid(pid, 0) + try: + _, status = os.waitpid(pid, 0) + except ChildProcessError: + # The child process is already reaped + # (may happen if waitpid() is called elsewhere). + returncode = 255 + logger.warning( + "child process pid %d exit status already read: " + " will report returncode 255", + pid) + else: + returncode = _compute_returncode(status) + os.close(pidfd) - returncode = _compute_returncode(status) callback(pid, returncode, *args) def remove_child_handler(self, pid): diff --git a/Misc/NEWS.d/next/Library/2019-12-05-18-21-26.bpo-38982.W3u-03.rst b/Misc/NEWS.d/next/Library/2019-12-05-18-21-26.bpo-38982.W3u-03.rst new file mode 100644 index 0000000..b591209 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2019-12-05-18-21-26.bpo-38982.W3u-03.rst @@ -0,0 +1,5 @@ +Fix asyncio ``PidfdChildWatcher``: handle ``waitpid()`` error. If +``waitpid()`` is called elsewhere, ``waitpid()`` call fails with +:exc:`ChildProcessError`: use return code 255 in this case, and log a +warning. It ensures that the pidfd file descriptor is closed if this error +occurs. -- cgit v0.12